IROCZman15

iTrader: (25)

Figured I would start a separate thread from my other threads(listed below at the bottom of all this mess of typing) because this topic is strictly for a specific goal that I am hoping to achieve. Basically, over the course of the 22 years that I have owned the car, I have always dreamed of pulling a wheelie that I can be proud of. I have achieved almost every other goal I have ever had for the car (run 10's, win big awards at big car shows, handle its own in autocross, etc) but the elusive wheelie has yet to be conquered. I know that the car is launching really well, and when I am truly racing or looking for my best timeslip, I WONT want it to wheelie, so I would like keep it setup exactly as is with a timeslip goal in mind. It is currently cutting a 1.44 in the sixty foot and lifting only the driver's side tire just 1" inch or so off the ground. The goal would be a 8-12" high wheelie that I can get a photo of, print it out on a large scale, and have it up on the garage wall. Somewhat juvenile of me, but I am determined to make it happen.


Currently, to get that 1.44 sixty foot I am launching off the foot-brake with a ramped-in progressive nitrous shot that comes in at 3,500 rpms. I do not have a trans-brake, so foot brake is what I am doing, and right around 1,800-2000 rpms is when the car starts to creep and push through the beams, despite a 3400 converter. I do have a line lock, but launching off of that is soft and lazy, so I only use the line lock during the water-box burnout.

The transmission is the top-dog that Dana at ProBuilt automatics offers and it has really been "put through the ringer" but is in very perfect condition. Probably close to 100 dragstrip and nitrous passes (10s 11s 12s), about 70 autocross runs and close to 11,000 miles; the trans has been astonishing fantastic. I have been reaching out to Dana at ProBuilt Automatics for the past 4 weeks, but have yet to hear back from him. I did speak with Mike, who assembled my awesome transmission 5 years ago on behalf of Dana and he didn't have any transbrake recommendations for the 700r4 that would be up to snuff. When I did the engine upgrage back in the winter of 2020, I spoke to Dana and Andre (at Edge Racing converters) and we wanted a street/strip friendly stall, so we went with a 3,400 Street STR converter. http://www.edgeracingconverters.com/...ions-p-35.html Andre knew nitrous was coming and anti-balooning plates are in the converter too. On almost all of my naturally aspirated datalogs (well over 100 datalogs), the converter seems to flash right around 2800-3000 rmps; on a nitrous launch, it flashes almost right when the nitrous comes on, around 3,400 rpms. I am wondering if either having this converter re-worked for a higher stall rpm would be good, OR keeping this converter while occasionally swapping it out for a higher stall drag race converter which MAY get me those wheelie shots and a slightly better launch/timeslip (maybe). I would then swap in the edge 3,400 converter for autocross season and if I won't be drag racing for extended periods of time. I have modified a lot under the car in order to get access to the trans, so pulling the trans backwards from the engine to swap a converter out is really not a terrible job at all. I called Andre at Edge racing today and we chated for a bit. I am having a mental brain-block about how to make all this work in relation to the "torque multiplcation" effect that the converter gives. He said I have teh best chance of pullign a wheelie by snapping the car WOT from an idle or high idle. yet when i do this, teh converter still flashes around 2800 rpms and the car leaves good but not violently. He did agree that something liek a 4000 rpm converter would be better for drag racing only, but he said it would kill the car in autocross and street driving would be comprimised a bit. He was adamantley against any sort of transbrake, for a multitude of reasons.

As for the transbrake, I know that Dana is not a fan of them, and I now know that Andre at the converter shop is also not a proponent, and yet so many people will say a t-brake will be fine, BUT just not on a 700r4. Yet, I have the 700r4 and I am NOT changing tramsmissions; not an option whatsoever. TCI seems to be the only company selling transbrakes for a 700r4 but I have read mized reviews on this thirdgen forum and across the web about it. I also don't want to have a reverse valvebody because I like having my shifter go PRNDD21 and would NOT like it to be PRN12DD. The heat that gets put into the transmission fluid while using a transbrake is not something I am fond of,and the hassle of having to hold down the transbrake button while putting the car in reverse, steering, and backing up also seems to be not worth it for me since I do VERY often street drive this car. I think I am 95% going to cross the transbrake option off of my list.

My throughts were to maybe give another converter company a shot, perhaps vigilante or Yank. Lots of people have success with Yank, especially their Yank ss3600 converter. I am almost thinking a 3800 or 4000 converter would be what I would need for that elusive wheelie though? But, related to "torque-multiplciation" and snapping the car to WOT from an idle at the starting line, would the converter flash to 4000-ish rpms and give me that twist to the driveline, or what am I missing. For some strange reason, I seem to have my brain clouded up on how to make sense of all this.



Car details: 1987 iroc-z street/strip/autocross/show/no trailers
- weighs 3420 pounds without me, and 3620 with me in it.
- 406 gen 1 sbc with holley efi and single stage of nitrous (up to a 175 shot)
- engine made 531 hp at 6000 rpms and 513 torque at 4800 rpms
- comp cams hydraulic roller 245intake 245 exhaust at .050 and .600 lift with a 110 lobe seperation
- 700r4 prostreet elite trans with 3400 edge racing converter
- moser 12 bolt with 3.91 gears and detroit trutrack and 33 spline axles (edited to say 3.91 gears not the typo of 2.91 gears)
- mickey thompson et street SS drag radials 275/60/15 which are 18" tall (the old setup was a 26" tall tire on the iroc wheels, but thats all gone now, I am on 28" tall tires forever)
- front suspension is lakewood 90/10 drag struts with moog oem replacement springs and UMi a-arms
- rear is umi and founders tube/adjustable everything, koni adjustable shocks set on medium , cut-down moog iroc replacement springs, and airlift- drag bag air bags 6 psi drivers side and 11 psi pass side.



build/engine/racing thread: https://www.thirdgen.org/forums/tech...g-install.html
nitrous thread: https://www.thirdgen.org/forums/powe...ous-406-a.html
old COTM thread for details on the rest of the car: https://www.thirdgen.org/forums/auto...tm-winner.html




and a video (no audio) of the above 10.60 run, if you look closely at the hood, you can see the hood shake when the front drivers side tire comes down from this very very small wheelie.


naturally aspirated datalog, RPM is the dark red trace, and from waht I have been told, that little "bend" as the red rpm line climbs first gear is whent he converter flashes, right around 2900 rpms on that pass. :

mw66nova

iTrader: (13)

put a 4.10 gear in it and have a converter built to stall about 5000 rpm and hold on for dear life. no transbrake required.

i bet it runs 10.30's with these 2 things too

IROCZman15

iTrader: (25)

true, that would do it! Glad to hear from you Matt, much thanks!
I initially had 3.55 gears in the rear and decided to change to a 3.91 ratio, which I was pretty sure would get me to have the wheels come up (before nitrous), and I was definitely disappointed when it did not. I really love the 3.91 gears that are in it now, and my tire height for drag racing and street and autocross is perfect with these 3.91. I am going through the finish line beams at 6,100 rpms(ish) and I have no plans to ever change from the 3.91 rear gear ratio. the 5,000 converter would work! but whew thats giving up a lot of street manners, and this car is first and foremost a street-car to the core.


I called yank converters today and chatted for a bit. he mentioned that something in the 3800-4000 range would give me the torque multiplication that I am looking for, but he wanted to review some of my car specs and engine tech info so I sent him a (long detailed) email a little while ago.

Oh, and one more thing that I forgot to mention in this first post of this thread... is that the converter MUST have a lockup feature. Especially for all the highway driving I do, I do need, and very often use the converter lockup. I have it wired to a toggle switch that I control, there is no computer control, just me.

mw66nova

iTrader: (13)

2 things:

1) your original post said 2.91 gears. i was thinking 1.44 60 with 2.91 gears was pretty good, but is why i suggested the 4.10s. 4.10's over 3.91 would not be a big jump.

2) with today's converter technology, we are driving 6500 stalls with no lock up and no overdrive for 1000's of miles on drag week with n/a combos. 5000 stall speed will feel sluggish but once locked up on the highway, it'll act like stock. with the cam you have and the torque peak at 4800, you will want a 5000+ stall speed to get you to your goals.

the big problem i see is that the 700r4 and other lock up converter cores simply don't have the space for the fin angle required for that high of a stall speed, and it may be impossible to get there. so if you're dead set on keeping the 700r4 you may be limited anyway. 4600 may be all the more you can get. either way it needs a LOT more converter if you want it to wheelie.

I'll be at a track rental at Cecil on October 2nd with my car. Try to come down with the car. it should be a good time!

Orr89RocZ

iTrader: (20)

How do you autocross the car with 90/10 fronts? Or do you swap shocks and springs? Sorry if i missed that.

Steeper lca bar angle, shorter torque arm, lower rate front springs can help

biggest thing imo would be higher stall and hitting the nitrous off wot immediately. Hit it off the converter flash point so it hits the car hard as possible. It may come up then

seems relatively heavy, how is the front rear bias? Anything you can do to lighten front weight?

even low 1.40 60 on my nitrous 383 3600 stall never lifted front end. My turbo car in the low 1.20’s never did either its just too heavy and not enough suspension working on the front end with the old long arm and flat bar angles.

skinny z

I can't argue with any of the above.
Your rear gear with the TH700 1st gear gives a pretty steep launch ratio. 3.06 x 3.91 = 11.95. That's like a TH350 with a 4.74! So I would think you have that covered.
Although I haven't put it into practice myself, other than an off the shelf 10" convertor (which I have to say provided a night and day difference), I'd go straight to Yank and get their spec.



With a potential 4400 stall and lockup, you're most of the way there.
The problem I've seen is that you simply can't footbrake to 4400 RPM (which by what I've read of your build is just about where you make peak TQ). I've watched my convertor flash stall on a chassis dyno to 4000. (at least as witnessed by an in car video) and yet the max is about 2200 footbraking before I push through the beams.
You'd mentioned contacting Dana at ProBuilt. I'd be of the same mind. See what a transbrake might involve. It used to entail a manual/reverse shift valve body. (Is that right?). Something you'd have to consider for sure if that's the case.
Anyway, that's my two cents. The two posters above have miles on me in terms of drag strip passes. I look to both of them for advice by following what they've accomplished. Although in one case it's an 8000 RPM stick car and the other is twin turbo BBC,. Yikes! A little old NA 350 doesn't stand a chance (unless we're index racing...).
Watching with interest as always.

skinny z

I hadn't even thought about how the nitrous plays into any of this.
A convertor spec's for nitrous as I understand it is quite different from one that isn't. Sounds like a hard decision would have to be made one way or the other.
other.
As mentioned, you go forgo the transbrake and hit it with the juice WOT at the launch but that would take a convertor that's designed to handle that. How it would translate to the street is something I can't comment on.

LB9GTA

iTrader: (1)

My 2 cents.
If you are set on the 7004r, then you have some options left.
Spray nitrous quicker and more of it.
When I had my 383 with 7004r with 3.73 gears, I couldn't lift the tires either (1.5 60ft)
Then went to a 400 with a th350, 3.73 gears with a 3500 edge converter with 150shot of nitrous at WOT (foot braking) Got a 1.4 60ft, and lifted one tire 6-8".
More rear gear would help.
Moroso drag springs in the front would help.

In saying all this, wheelies are cool...until you start breaking stuff on the landing.
I had to get to a 200hp shot on stock front suspension in the low 1.3x's when I did a big wheelie.

vorteciroc

Why in the world would you want to Wheel-Stand the Car???

It will slow you down... and most of the time damages the Car!

I have Customers spend fortunes to prevent Wheel-Standing...
LOL! and yet... you want to do it!

skinny z

The money shot!

LB9GTA

iTrader: (1)

And here's another thing you need if you want to do a wheelie.
SLR!
http://www.wallaceracing.com/calc-slr.php
The more you have - with traction - the faster your 60ft will be.

vorteciroc

Well then some Slicks...
and adjust the Rear Suspension to keep the weight on the Rear Tires with minimal Leverage from the Front-End.

Buy yourself some protection/ Jimmies (Hans Device/ Neck Brace for your Back and Helmet) for what I call the Sex Swing...
You'll get the Wheel-Stand Bug! Like the Clap from a Pro!

Just be Ready for the inevitable... Flipping the Bitch on Her Back is not as much of a good time as it sounds!!!


=Weeeeeeeee! Now we're having fun!


=I Think She broke my Dick!

skinny z

I can appreciate all of that Vortec but you have to admit, any Super Stocker worth his weight carries the front wheels.

This is the stuff I grew up with and it's when most of these cars were new! The bug had bitten.


That said, my chassis building friend said he always tuned the chassis so the car was "on it's toes" for the trip. 40 years building cars and NHRA racer. I took him at his word. (Saw a lot of the "new" Nostalgia Gasser class cars going through his shop.)

IROCZman15

iTrader: (25)

first of all, thank you guys for your input on this topic. pretty much everyone here has some real-deal knowledge on drag racing and I appreciate any/all advice. So, thank you.

I'm definitely not changing transmissions and not changing rear gear ratios; gotta keep this car "as is" for the street and autocross realm of things, especially converter lockup feature for my multi-hour long highway drives to and from shows, races, events. However, dragstrip/launches/wheelies I still seek MORE.

I spent a lot of time digging through threads on this site, and even though some of the stuff is from the mid 2000's it is still pertinent to me and my wheelie goal. One of the more valuable threads was the "post your best 60 foot" which included descriptions on how some guys got their fast 60 foot timeslips and wheelies. link: https://www.thirdgen.org/forums/orga...uspension.html also, some other good info in various racing threads and I used the google search to find, as well as infinite scroll feature.

mw66nova:
I am glad you caught my major typo regarding teh gear ratio numbers. I totally goofed there, it should have said 3.91 gear ratio, not 2.91. Definitely 3.91, I put them in last spring. I'm interested in hearing about the 5000+ stall number you suggested, and I have been hearing numbers like that more often. Lockup is a key feature for me to have. I would like to use all the power that the engine has (and the nitrous) and optimize it with a good converter, and I feel that my current converter is hurting my timeslip/wheelie a bit. I have never been down to Cecil, and would freaking love to go. I am waiting to hear form some of my NJ guys if they are doing the usual track -rental at Atco in the late fall. If I find out that they are not doing it this year, I might take you up on that Cecil trip instead!

Orr89RocZ:
sorry, I didn't clarify that, but for autocross I run koni yellows on all 4 corners and they are working fantasitc for that. However, for drag racing events, i swap out the front koni struts for the lakewood 90/10 struts. Super quick and easy, maybe 30 minutes in total. As for the suspension stuff, I think I am almost at my max adjustments for what I currently have on the car. LCA's in the lowest spot, I do have the S&W torque arm that is short and goes to its own crossmember that connects the right/left subframe connectors, and the drag bags. I've considered the moroso trick springs, people have had luck with them... but it takes a while to swap front springs on my car (drop spindles with stock height spring) and its not something I could do the day before a drag race event. I'd have to leave them on the car for weeks, and that might kill its street manners. As for spraying the nitrous early, thats kinda what I have been sneaking up on doing. When i first installed the system (fall of 2021) I had it only activate up int eh 4,000 rpm range. however, as of my last dragstrip pass on May 1, 2022 I let the nitrous come on (progressive ramp) at 3400 and thats when it lifted the front tire just a little bit (see video in post 1 with hood shaking ). I have always been cautious about spraying too much nitrous at the hit and in "lower rpms" as I was afraid of bending rods etc. Here is a screenshot of the datalog from that pass on May 1st, and I ramped in the 175 shot over 1.2 seconds, so it started as like an 87hp shot ish that ramped to 175. on that pass I was able to foot-brake hold the car and launch at 2,000ish rpms. red data-line is rpms and you really cant see any converter flash because 1st gear wicked up so quickly. The car is heavy, but not much more I can do to lighten the front end without cutting out the oem bumper area and building a tube frame deal. I have the battery in the back and engine bay is relatively empty and streamlined. Not interested in a tube K-member, just not going to put on in this car. I know you had the nitrous 383 setup in your car for a while, so lots of my current dragstrip goals are things you have conquered earlier on.


skinnyZ:
as always, thanks for the advice you bring to the table. So I remember calculating the STR and all those ratios back when I was in the research phase of planning my rear gear ratio swap (from 3.55 to the 3.91) I remember getting the results and thinking to myself, dang...this is sure to pull a wheelie. When it didnt, I was surprised, and even a set of skinnies, the lakewood 90/10s and some other mods still didn't lift the nose up so i got disappointed. However, the car was launching pretty good and running nice timeslips, so I wasn't really deeply bummed out. I do remember calculating the STR though. I have been on yanks website a bunch and I am waiting to hear back from Dave there with his thoughts and advice also. I see that you mention hat I would still have difficulty in keeping the car stationary at the starting line if I foot-brake beyond 2000ish rpms, even if I did have a loose 4000+ converter? You think that would still be the case? I don't know the science behind why this would be, so if you or anyone wants to expand on that topic for me, I would certainly appreciate it. If thats true, than I might certainly be stuck where I am at, in small-wheelie-ville.

LB9GTA: I hear ya about the more nitrous early on, and if you guys think its safe to bang a 100or125 shot at launch, ramped up to a 170or200 shot, thats what I could do. I know your earlier powertrain was also similar to my current one, so your experience is valuable to me big time. Just above I discussed the trick springs, gears, and whatnot, so i don't want to re-type it tot his already long thread. Your wheels up avatar/signature (and Diggler) are some of the ones that keep me itching for that wheels up photo. Of course the reality of doing a wheelie is coming down to the track and breaking stuff, so I am prepared for that as much as I can be. That's kinda why I only want to do it a few times (maybe a big one on a full nitrous launch) and then dial-it-down from there where I can find the optimal launch scenario.

vortechiroc: yea man, I hear ya indeed. As mentioned, im my first post, the big wheelie moment is for pure selfishness and almost a lifetime goal type accomplishment. having a nice photo of the car I've owned and built since high school (22 years of ownership' I'm 38 years old now) would just bring a smile to my face every time I see the photo. This car is with me for life, and I just freaking got to get that wheelie photo that i grew up seeing in my dad's friends racing garages, car magazines, and wheelies all over the internet. As skinny said... its the "money shot" and that's really the truth of it! I do have one of those Simpson neck-collars that I used to use for the few road-course racing events that I competed in with the Optima Batteries ultimate street car shootout. I don't ever plan on attending the Byron Wheelstand competition or something like that, those guys are WILD! but a clear foot of air under the nose of the car at the launch would be freaking awesome for this street car.

DIGGLER

iTrader: (1)

moroso drag springs up front with loose shocks
hit the nitrous right away with no progressive. converter needs to flash to at least 3500+
more nitrous

it will eventually go on the rear bumper and you will never want to do it again. lol

mw66nova

iTrader: (13)

this isn't a 4000 hp pro mod. i don't think he's going to have problems with it getting out of shape pulling the wheels 12-18". and yes, stock eliminator cars that run 9" wide tires will ride the ring gear hard, to get the car up on the tire and not lose it. those cars are INCREDIBLY efficient. they will 60' harder than cars seconds faster than them, then run very low MPH for their ET due to a lack of power. (that's OK, MPH doesn't win races).

anyway, IROCZman15, find me on Facebook if you haven't already and we can chat about the track day. depending when the atco track rental falls (if they have it) i may be interested in making a trip up as well.

Orr89RocZ

iTrader: (20)

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honestly i may say its not lack of power, but they run the proper et for the mph because they use the power most efficiently. Everyone else like my turbo car is very inefficient and dont use the power efficiently and lose ET lol.

QwkTrip

iTrader: (22)

I'm a little worried what can happen here....

There are tricks that can be played with suspension to get the nose of car to travel but won't the car come crashing back down if he doesn't have the power to carry a wheel stand? In other words, if the car doesn't really want to wheel stand, and you make it wheel stand with suspension tricks to flick the nose up, then it's unlikely to return to terra firma softly. Is that right?

mw66nova

iTrader: (13)

in my experience, if it doesn't have the power to keep them way up, it won't go way up to begin with. when i say way up, i mean up far enough to actually be a problem with it coming down.

the damage on my car, which is a stick shift car, was done due to 2 things. 1, the height. it was way higher than i see irocz's car going. 2, i lifted...in a stick shift car, with the car in gear. so instead of just floating back down like would happen in an auto car, or a car out of gear, it got mechanically driven into the ground. i lifted because the car was going left.

skinny z

With blasting the nitrous on green would that mean that a nitrous specific convertor would be needed? And if that's the case, how would that convertor behave in a more traditional sense. As in street driving or autocross? Don't forget the lockup feature.
I'm asking for myself as much as the subject line.

mw66nova

iTrader: (13)

so it'll be tighter on motor, meaning that if anything, it'd drive nicer.

but it'll be slower on motor as well. that may be a problem, or might not be. that's up to IROCZman

IROCZman15

iTrader: (25)

Thanks fellas. These long and detailed tech threads that I start up are very helpful to me, and hopefully to others for years to come. Matt, unfortunately I don't have facebook or any of the big socialmedia accounts, I do have youtube and I subscribe to your channel (and do watch all the videos). I met you back in 2015 at the Carlisle event and bought one of your steering shafts on-site that day. its been in the car ever since. I am excited to get to either Atco or Cecil this fall, and I gotta do whatever I can to make it happen! I can keep in touch with you here via PM's and perhaps emails as time gets closer. For the next months, I am bouncing around to a few car shows on weekends, and then once the new converter is ordered and arrives, I will then install it and get back on the dragstrip (Island dragway 20 minutes from my house) for some testing.

Anyways, yes, I don't think that I will ever put this car that high up where it would hit rear bumper and then come crashing back down to earth. I know that big big wheelies are problematic, so I am looking for what I guess I would call a "middle height wheelie" if thats a proper descriptive term! One of my thoughts, was if I feel the wheelie coming up "too high" I would stay full-throttle, but just let off the nitrous button. I know that coming completely off power will send the car crashing back down, so finding a way to bring it back down is important. Staying full WOT while letting off the nitrous was my first thought. Or, another option would be to simply shift into 2nd gear and take some rpms out of the powertrain? or both?

I am waiting to hear back from Yank converters and I may give them a phone call on Monday or Tuesday to see if they had a chance to look over the specs and info I emailed them. I will also ask about their build/shipping timeline. If one of their off-the shelf converters fits my needs, that would be ok. It would probably be the Yank "SS series" in a 4000 or 4400 . link: https://www.converter.cc/93_97_F_Body_s/64.htm . Surprisingly, the Yank "pro series" only comes in 3200 rpm or 3600 rpm options, or at least thats what is listed on their website. The SS series drop down option only goes up to 4000 but on the STR chart page, they do have a listing for the SS4400. link: https://www.converter.cc/STR_Chart_s/82.htm also. I have to make sure they understand that I do need/use lockup for highway driving.


*** One BIG question I still have, is aside from the converters changing the "flash stall" rpm,, how do we put a number/value on what the new "FOOTBRAKE stall" will be? For this wheelie adventure, I know flash stall is important, but I am thinking that footbrake stall is even more important. It has been mentioned to me that even with a looser converter, my footbrake stall rpms might stay about the same, and I might be stuck still launching from a 1800-2000 rpm footbrake launch and then banging in the nitrous (all at once as you guys recommend). How can I get a higher footbrake rpm launch, say in the neighborhood of 2800-3000 rpms so I can bring in the nitrous right away and that will really bring in the converter flash? What variables need to change to increase footbrake-stall?

skinny z

I've experienced two different phenomena when trying to get the highest foot brake stall. One is the locked front tires are literally skidding through the beams. The other is that the clamping force is insufficient to prevent the car from rolling forward.
I found that after the burnout, blipping the throttle a few times will boost the vacuum and keep the brake booster fully charged. This appeared to help with the clamping force.
As for the skidding, this changed with the track prep somewhat.
That said, my current convertor is TCI's Super Street Fighter. As seen in the chart below, it's expected stall is 3500-3800. Indeed, on a chassis dyno, I've observed the tach swing well past 3500 instantly at the hit. While not a true indication of what happens at the track, it's pretty close.



Notice though what happens with the same convertor is behind a big block. More stall. This would trickle down the foot brake stall too. To some degree anyway. The point is, in reference to to your question, is besides the convertor itself (and Yank will give you better insights into this) is that the stall is a function of torque. More torque equals more stall.
If your new convertor allows for more RPM when holding the brake on, (that's the if you have to confirm) and you get more into the meaty part of your torque curve, then it will allow even greater stall.
A transbrake would allow for greatest application of throttle. The transmission is locked up against itself and the only thing between it and the engine is that fluid coupling.
S/S class allows a transbrake. The Stock class does not.

mw66nova

iTrader: (13)

more footbrake stall (not really that important) would be obtained by better rear brakes.

we messed around with a 2-step on my cousin chucky's car. he can go WOT on the footbrake with the 2-step. we've tried all the way up to 4500 rpm launch speed without creeping forward, but he's got strange engineering drag brakes all the way around. it's more consistent this way, and it sounds cool. but he didn't really pic up much ET since flash speed is still the most important part of this.

skinny z

Interesting. I'd thought about trying to apply the parking brake to get all four wheels locked but the logistics are difficult. And impractical.
That said, you mention not picking up much ET. That would mean there was some gain right? But being on the limiter, I was always felt was unnecessarily hard on parts.
But leaving AT peak torque rather than running up from just off idle TO peak torque would seem quicker, and more consistent as you've said more or less. There's obviously an adjustment needed in reaction time too.
How this might translate into a wheelie I still think goes beyond the converter as stated. Gearing and weight transfer all play equal parts. But as an all round performer, and a pretty good one at that, IROCZman has got to understand the limitations.

Orr89RocZ

iTrader: (20)

Strange offers a dual caliper rear kit for footbrake classes

could also setup a proportioning valve and set more to rear with a soft pad to increase cold clamping force for the strip

in my experience i always got best 60’s the higher i could foot brake it. But i can see converter spec and design could have more influence than starting footbrake rpm lol who knows. But trans brake set to max stall speed should always leave hardest so rpm on footbrake should matter

IROCZman15

iTrader: (25)

just typing this quick reply tonight, will type more of an update tomorrow instead if I have enough free time!

As for more rear brake bias. I should explore that. I have a nice Wilwood adjustable prop/combination valve that pretty much set to the "sweet spot" after some street testing, but this was back in march 2020 when i redid the engine bay and installed the engine. I adjusted it once from there during an autocross event back in June 2020, but have not touched it since. I think (correction, I know) I can give it a LOT more rear brake if needed) but I think I was cautious about having too much rear brake and possibly causing the rear of the car to get a little unsteady at speeds if the front brakes aren't pulling the nose of the car down. So, if you guys also think I could crank up the rear brakes via my wilwood in-line valve, I am certainly willing to try it.

As for the two step feature. I have that feature with this Holley Sniper EFI system, and in fact I tried using it for better launches back in October of 2020 on several different dragstrip test-n-tune events. Almost every time, the car would bog, as the 2-step was giving the oxygen sensor crazy readings, and therefore the +/- fuel compensation went haywire, and it would really put a hurting on my base fuel tables. Even when I tried to keep the lower rpms in open loop, the 2-step just made the oxygen sensor very unhappy. I was real hopeful that this would work, maybe I missed something in the overall tune file, as I was in the very early stages of learning the holley efi and tuning in general. I am also willing to give the 2-step feature another go around, and that I can try out on the street a little bit before going to the track. I wired the 2-step to a momentary button on the top corner of my brake pedal, so that when had my foot on the top corner of the brake pedal and the button was pushed down, the 2-step rev limiter was activated. So when i launched (and got off the brake pedal) it would also release the button and therefore remove the 2-step rev limiter, sadly it just bogged. The last video listed below is a perfect example of the issue with pushing through the brakes fail and a 2-step fail! I had the 2-step limiter set for 2,000 rpms, at the line it began to creep forward as it pushed through the brakes, so I just decided to launch, and then it bogged after coming off the 2-step. Whew, these old videos are tough to watch and things have improved a whole lot, but the tech info still applies.. thoughts?

2 step testing (october 2020):

2-step testing to 5,000 rpms (October 2020):


Bogged launch using 2-step (October 2020)

Another bogged launch using 2 step whichw as set at 2,000 rpms (same day October 2020)
(also, pushed through the brakes and pushed through the starting line)



Spent 51 minutes on the phone with Dave, the owner of Yank Performance Torque converters today... will type all that out tomorrow.

Camaro71

Weld a piece of threaded bar as far as possible in the trunk, add lifting weights when on the track, fasten the weights and let nature forces do the rest.

mw66nova

iTrader: (13)

i don't run a brake proportioning valve at all on my car.

Orr89RocZ

iTrader: (20)

holley should be dropping out of closed loop when on the two step. Mine does. But i also dont use learn. I just have correction when needed but it’s usually a few % if needed. Once your tune is solid, and correction is low, disable learn and limit o2 correction values. Also can limit the correction advance level so its not as sensitive.

IROCZman15

iTrader: (25)

yea, I think that I was too early on in the beginning stages of learning efi that I realized I was not initially having success and gave up on the 2step situation. Since it was October of 2020, I just gave up on it for the year and in 2021 and currently in 2022, I had better success with the car and never re-visited the 2-step idea. However, now I am ready to give it another shot. I must have had something awry in the closed loop and compensation parameters back then, but I can re-visit that now. I usually always keep my closed loop comp numbers between 0%-5% correction in my lower rpm range (up to about 2000 rpms) and then 5%-15% from about 2000 rpms to 5000 rpms, and then a little higher up top. I have the speed at which the O2 sensor and ecu communicate and make fueling changes at moderate/slow, (this was discussed in my long exhaust thread from this winter time). I think thats what you mean by "correction advance", and I did that because I moved the o2 sensor bungs almost 12" downstream from where they used to be on my shorty dyno dons headers, to the straight portion of the y-pipe I made that's after the long tube headers. The tune should be good now, but back in October 2020, the tune was not dialed in, so perhaps that was another part of the problem back then.


So, as for the converter, I ordered a TCI Street-Sizzler with an 1800 rpm stall.
Just kidding; yesterday I talked to Dave at Yank on the phone for just short of an hour and we discussed all aspects of the car and its uses. I had initially been thinking about their SS4000 converter, but then we discussed that having the car launch like an animal, and have a very quick 60 foot, 8th mile and 1/4 mile e.t. is much more important than top end mph. I'm not a bracket racer, but just a guy with some E.T. goals and personal car racing goals on my lifetime checklist. He stressed the importance of "shift extension" (rpm drop between gear shifts), which he likes it to be no more than about 700 rpms.. yet mine is always about DOUBLE that. I have datalogs going back to march 2020 showing the huge rpm drop in between shifts while naturally aspirated, and also on nitrous. Almost all these datalogs can be viewed as screenshots which are posted on my main build thread (link above in post #1). Dave explained that his Power Adder Series converters can improve my shift extension tremendously. And, as it says on the website, "the Power adder converters will couple up quicker and multiply torque harder"

The converter is the PAS-3800.
link: https://www.converter.cc/product_p/pas-lt.htm

Its a 9.5" diameter converter and its fully billet, so there will be no chance of it ballooning out. The single disc clutch is apparently quicker reacting than the triple disc, so I went with single disc. Even though the webpage says "LT engine family" it is just the websites name, it is fine for my sbc 406. The stall speed is 3800 which I think should be a great blend of street manners and hard hitting launching, especially on the nitrous. Yank offers a one-time FREE re-stall during the first year of owning the converter (just pay shipping costs) so, if any adjustments are needed, I can send it back in. Since I have ruled out ever doing a transbrake on this car, the 3800 rpm flash stall in addition to bringing the 2-step rev limiter back into action and adjusting rear brake bias better) should get me the ability to footbrake-stall the car up to about 2800-3000 rpms. Dave said the car will cut down my N/A 60 foots from a mid 1.6 to probably a low 1.5 or high 1.4 range. On nitrous, he said I should definitely be seeing some 1.3 second sixty foot launches with the wheels up, if all other variables with the car work properly of course. He definitely said the same as you guys all did.... to spray more nitrous and sooner, so I can do away with the soft progressive nitrous ramp, and probably spray a 150 shot out of the hole (above 3000 rpms) off of a footbrake. This will let the engine start climbing the "meaty" part of the torque curve quicker....and get great torque multiplication too. The converter will have full lockup functions also, which is very important for some of my long long highway drives to shows and events. Odds are that this converter will be better than the edge converter in many ways, so I will probably end up selling the perfectly good/working Edge converter, maybe over the winter to help offset some of the $1050 cost of this Yank converter.

Its about a 3-4 week waiting period for it to be built and shipped, so I am going to hit some car shows in the next few weeks.

If anyone has any comments or questions that might be of importance, please let me know and I can contact Dave back before my order is slated to be built. Thanks again everyone.

Orr89RocZ

iTrader: (20)

My 383 would 1.55-1.57 on motor with 3600. The 150 hit off the launch went 1.41. So it will improve. Just need the front end to travel up which is gonna be combo of spring rate, shock rebound and rear suspension geometry frm torque arm length and lca angle etc

TTOP350

iTrader: (8)

Maybe silly if me to ask but I've seen no mention of the front sway bar. I'm assuming it's not on the car right?

IROCZman15

iTrader: (25)

Good stuff Orr, hopefully my suspension components are up to the task, and if not, hopefully they can be adjusted to do so. I never expected this car could potentially go in the 1.3x sixty foot, (and it has not), but to hear that it is somewhat possible...man that makes me excited!

TTop350: good catch, I should have included that in the first post. FOr Drag racing, I take the front sway bar off the car completely. Been doing this since mid 2020 and thats probably the only reason that the very small 1" wheelie I occasionally do get, is possible. I bet if I left the front sway bar on, the car wouldn't lift that driver's side tire up at all. Its the oem sway bar that comes off, and I put it back on the car for autocross and if I am not going back to the dragstrip for a few weeks, I will put it back on the car. Oh, and the rear sway bar (oem iroc) does stay on the car all the time for street, dragracing and autocross its obviously always on.

I was initially curious why yank would not recommend a converter in the 4400 stall rpm range, but he explained a few reasons to me and essentially, since this street car will always be a street car, the 3800 is what got the go-ahead for the order.

As for my holley efi tune files, the fueling and torque curves of the engine will be the same right? The target air fuel ratios and timing I didnt plan on touching. This whole converter deal will only multiply the existing engine torque differently (better), and it shouldn't require me to plan on making fueling/timing/afr adjustments, right? I always datalog dragstrip passes, but I am just trying to think ahead .

Orr89RocZ

iTrader: (20)

It shouldn’t change much. Different loading of engine can change fueling slightly but not enough to really be worried imo with closed loop corrections. Leave it to correct plus minus 10% and it will cover any scenario

IROCZman15

iTrader: (25)

The new torque converter arrived today, after a 5 week wait, but I was not worried, despite being excited and impatient! But its here now and I am hopeful to install it tomorrow afternoon after my half-day at work. In recent weeks I did a good amount of driving and did some car shows with the car. In fact, I went to a local car show on Sunday and won the 1980-1989 vehicle class, then came home and immediately pulled the transmission and converter in the car because I knew the yank was coming this week. The Edge Racing 3400 converter with lockup served me very very well up until I removed it on Sunday, and I am not sure what I plan on doing with it yet. It is in perfect working order, and would be killer for someone to upgrade to if they have a stout small block chevy and 700r or 4l60.

I hope to get to the dragstrip this upcoming Sunday....... SO I have to get everything installed and go for a 150 mile break-in drive! Whew. That makes for a long day/night on Friday! Then if all goes well I will also have to switch over to the drag wheel setup and pack/load all my gear and tools.

Question about the fluid. For 5-6 years I have run a combination of AMSOIL Signature Synthetic ATF and the CAT (Caterpillar) ATF (non-synthetic as far as I can tell from its info) that is recommended by Dana at ProBuilt. Have had zero issues whatsoever. But now in the Yank beak-in paperwork, it says they do NOT recommend any synthetic fluid. I have just bought a different style of ATF that I was going to try, by AMSOIL, it is the "Super Shift" synthetic ATF for high horsepower applications. Should I still plan on using this, or not anymore now knowing that Yank says they don't recommend synthetic. What's the best thing to do here, keeping in mind that I plan on putting 150 miles on this car tomorrow evening and then drag racing on Sunday? Can I mix some non-synthetic Dex3 atf with some of the new AMSOIL super chift synthetic while also following Dana's instrictions to use some CAT brand ATF?
link to the AMSOIL Super Shift ATF: https://www.amsoil.com/p/super-shift...d-sae-10w-art/

vorteciroc

In 150 Miles or so...
You are going to remove the Oil-Pan, change the Oil-Filter/ Pick-Up, and ATF.

For NOW, just use some Dexron-III-H or Dexron-Mercon Non-Synthetic ATF (of any Brand).

mw66nova

iTrader: (13)

agreed.^

Also, depending on price, i may have some interest in that converter for another project i started. check it out here if you get some time.

IROCZman15

iTrader: (25)

Thanks for the replies fellas!
I do have an update for this thread, as I was able to get to the track on sunday for a a few quick passes and just when I was going to lean on it, the rain storms came and the track was done for the day. I have videos/photos/datalogs that I am still working on finding time to upload and then I will type up my re-cap of Sunday with the new converter, I just haven't had time after work these past few days. Perhaps tomorrow. I gotta do it soon, as I am planning on going back to the Dragstrip this Sunday. And, after that, I'll have to do another re-cap when I can find time for that!!

Anyways, Matt, yea.. my plan was to sell the converter once I established that the new Yank converter was doing good in the car, and so far so good. I will know for sure after this weekend. I would be willing to sell it to you for sure! I have your videos of that new build on my youtube 'watch later" list, which I also hope to get to find time to watch in the coming days.

So, stay tuned for a new post here in the coming days, but I'm impressed with the new Yank PAS 3800 converter so far !








Filling up trans fluid with the little buddy!

mw66nova

iTrader: (13)

keep us posted. as for the converter, i actually found a 3k stall 10" for cheap locally so i think i'm good, for now, lol.

IROCZman15

iTrader: (25)

Man, it took me a while to find the free time to type this up, sorry about that. Busy with work, newborn baby, yard/house projects, etc. Anyways, its a good update for a quick test session with the new torque converter, and I hope I can get more tracktime in ASAP before the weather turns too cold locally.

After getting the converter bolted in, trans back in, driveshaft, y-pipe, new spark plugs, fixing a stripped header bolt into the Dart 215 aluminum cylinder head, and topping off trans fluid, I went out at 11pm last friday night and put 121 miles on the car, making sure to lockup the converter manually probably more than 100 times, under light loads in several gears. The 3800 Yank converter takes a slight bit more throttle input than the 3400 Edge to get it going from a stop, but its not anything drastic or bothersome. Fluid temps stayed normal the whole time during this drive, but ESPECIALLY when I had it locked up. Wow, in OD (4th gear) on t he highway I was taking the unlocked rpms to about 3200 or so and then activating lockup, and it would take 900to1000 rpms out of it! The old edge converter took about 400-500 rpms out of it in OD, but this is double that. It engages with a solid feel and totally feels like I have a 5th gear; incredible. Got home around 12:45 am, well pleased. Put another 11 miles on the converter the next day while fueling up and whatnot, and then for the remainder of the 150 mile break in period I counted my slow and easy drive to Island Dragway as part of it on Sunday morning. This meant that I arrived at the track with no heavy-footed brake-stall testing or knowledge of how things would react under heavy load. Oh well, that's why I was just doing the Test-n-Tune portion of the race day and not the brackets.

After the usual safety-tech inspection I got the care prepped related to tire pressure and suspension settings.
** SIDENOTE; the tech guys confirmed some of the rumors that I had been hearing about most tracks starting to switch their big and medium sized race events over to 8th mile only. Only a few events and some test-n-tune events will remain 1/4 mile. I think a lot of people watched it happen elsewhere, and they said most north eastern tracks are doing this in 2023. Anyways, there was not that many cars and bikes there at the track, so I was hopeful that I would get a good 7or8 runs in, but we all knew that rain was on its way in the early afternoon.

Set front tires to 50psi, rear tires both to 18.4psi, rear shocks D: 2.5 and P: 3, rear air bags D: 7.2psi and P 10.2psi. I went off of the settings that were close to where I have had luck in the past, but I think I am going to soften up the bags, shocks, and tires in the future, just a little bit.

mid-typing photo break.





Pass 1:
Did a 6 second burnout, but I had the rpms too low and not sure if it was sufficient. Staged, and got on the footbrake while throttling up, but it revved past where I intended it to be, and slow pushed through the beams. So, I just launched and took the red light rather than restarting the process. The tires spun (track was glued but had no heat in it whatsoever yet). Pedaled it very quickly and it hooked and pulled the front drivers tire up a few inches! (Unknown about the converter flash on this pass due to the pedaling). Shifted at 6512 (rev limiter) and it dropped to 5138. Shifted from 2-3 at 6181 and it dropped to 5275. Crossed the finish line at 6042, but I was very tender on the throttle for my first pass with the converter, and I never went full WOT (see upper green line on the datalog, that's the TPS sensor. Normally it would be 100% the whole pass). Glad to not have any noises, weird vibrations, shakes, or issues after the whole converter/trans project; got the jitters out of my brain. DA was 1,441 and the temp was 64deg with 72% humidity. my mph was slow, but the sixty foot was better than I had EVER done wit the old converter, and again, this was with tire spin off the line!



Timeslip:



Datalog screenshot:



GoPro camera:



Dashcam:








Pass 2:
After a very brief look at the datalog, I jumped back in the lanes because there was talk of rain coming inbound. I kept the shocks and air bags the same, but lowered the rear tire pressure to 17.4 psi. Did another 6 second burnout, but had the rpms higher this time and got some heat into the tires. Footbraked the car to 18811 rpms and think I can go more in the future, but 1800 was my number last time or else it would push through the beams. Launched and according to the datalog, it looks like the converter flashed to 4773 rpms?! Datalog shows it went rich (9.6 afr) at tip in, so I will have to sort that out. It definitely lifted the front up on this pass, and that felt good. I short shifted it though, at 6267 which dropped to 5227 and then shifted the 2-3 at 6319 which dropped to 5365 in 3rd gear. Crossed the finish line at 6-63 rpms. It felt fast, despite the rich dip at the launch and the short shifting, and only being at a max of 91% throttle instead of 100% wot the whole pass, it went my fastest 1/4 mile e.t ever, of 11.67. Mph was slow, but I think I have an idea why. Most importantly,. the launch felt great, and the timeslip showed that It went 1.491 in the sixty foot, which is by far my fastest N/A sixty, and real close to my best ever nitrous launch sixty (which was 1.44). Dave Meyers at Yank had told me back in august, that my days of bring in the 1.6x second sixty foot zone were over and assured me I would be in the low 1.5x to high 1.4x sixty, and he was dead on, even on my first outing. WOW! Got a nice photo of it too. DA was 1412 and 64deg with 74% humidity.








Timeslip:


Datalog screenshot:


GoPro camera:


Dashcam:




Pass 3:
Decided that I was going to try an easy progressive nitrous pass, so I turned on the bottle. Small rain sprinkle came in and I had the bottle heater off. They dried the track quick and called us to the line, and I had no heat in the bottle so nitrous pressure was only 825 psi, very not-optimal. I had the 150 hp nitrous jets in there but had the shot ramped in from 50% of 150 hp over a 1.2 second sweep. So basically it was a 75 shot at the hit and then it would ramp to the 150 hp in 1.2 seconds. Did another 6 second burnout. Footbraked on the line to 1691 and launched. Car hooked and with the nitrous hitting, it looks like it flashed the converter to 5130 rpms. I short shifted 1-2 at 6297 which dropped rpms to 5717 in second gear (woah, only a 600 rpm drop! nice) Took second gear to a short shifting 6208 rpms and this dropped it to 5574 rpms in 3rd. I had set my high-side rpm limit on the nitrous to turn the nitrous off at 6300 so at the top end of the track it hit that nitrous rev limiter a few hundred feet away from the line, so I got off the nitrous button and finished all motor at 6263 rpms. Timeslip was pretty good, again, testing only today. DA was 1560 at 66 def and 74% humidity.





Timeslip:



Datalog screenshot:





GoPro:


Dashcam:




Was super motivated to get another pass in, and I had changed the nitrous settings to be a fixed all-in 150hp shot which would come on at 3,200 rpms in 1st gear. I heated up the bottle to 975 psi in the lanes, and just as they were running the motorcycles it began to rain with no chance of it stopping anytime soon. So, just when i had my confidence boosted up, the track closed for the day. Packed up the car in the rain and chatted with a few of my buddies before hitting the road. Drove the car home in the rain with zero issues. Overall a good first test outing, but I know I would have benefitted from a few more test passes. I am elated about some of the numbers I am seeing, especially the less severe rpm drop in between changing gears, which is something Dave Meyers said his converter would resolve! I had left the whole 4" mufflex exhaust system off the car when installing the converter/trans and I am definitely going to put that back on (later today probably) and do an oil change. I want to check spark plugs too, and a few other things, but I am super excited to get back out to the dragstrip for some more passes. Was planning on going tomorrow, but this rain from hurricane Ian is now here in NJ and it might wash out the whole weekend. Nonetheless, I am going to prep and pack the car to go race tomorrow anyways.
***Oh, and the photos I took of the photographers online photos, I DID buy two color printouts from him, but they will take 2 weeks to be delivered, so I didn't really steal these from his website, since I paid for prints.. I just don't have them yet.

So, some more track time, and a nice 150 fixed nitrous shot launch looks promising for getting both wheels up high in the air and a nice photo! And some real quick sixty foots I hope are also in store!

DIGGLER

iTrader: (1)

very cool! have you ever left with the all in 150 shot before? if not, i would back it down to a 75 for the first time and move up from there.

NoEmissions84TA

iTrader: (1)

That YANK converter really worked as promised.
Nowadays, it's a rare occurrence when that actually happens.
Congratulations.

Orr89RocZ

iTrader: (20)

Nice runs. Seems to be working out for you.

what you think is killing the mph on top end? Third gear is a long pull lol
95 in 1/8 should be more like 118-120 in 1/4 for a na car. I think my 383 was 92-93 1/8 and 117-119 1/4

skinny z

New power adder?

skinny z

This is what I was talking about with a properly spec'd converter.
That RPM split is awesome.
Flash stall equally impressive.
Now this gives me more motivation to proceed in this same direction. My shift RPMs are targeted to be about 6200(+/-) and that should suit the gearing. (That focuses in on my cam spec too with a well defined RPM band for a track engine.)

What do you calculate your converter slip to be at the stripe? 10%?

IROCZman15

iTrader: (25)

Diggler: yes, As far as my racing log book/notebook shows, I have done about 6 nitrous launches with a "fixed" shot and the rest were different progressive shots. Some were before I had the proper tire pressure range figured out and some before I added the rear drag-bag air-bags. I'd say most of em were successful, but heres what I came up with:
- September 24, 2021 (nitrous just installed weeks prior) Pass #5 a Fixed 125 shot. Went 10.993 at 122 mph with a little tire slip and the sixty foot time didnt print.
- October 10, 2022 Pass #4 Fixed 125 shot went 11.14 at 121mph with 1.48 sixty
- October 10, 2022 Pass #5 Fixed 125 shot went 10.93 with a 1.47 sixty
- October 10, 2022 Pass #6 Fixed 125 shot went 10.97 with a 1.50 sixty.
- November 14, 2021 Pass #2 a Fixed 150 shot tire spin showed a 1.76 sixty and an 11.23@124 mph.
- April 15, 2022 Pass #2 Fixed 150 shot (on a very cold friday night track session) went 10.87 at 126 with a 1.555 sixty

So I am hopeful that on a hot track surface I might have some luck. Would like to see how the converter reacts too, and if it doesn't take it, I can dial it back.

NoEmissions:
Yea man, I had such good hopes for this converter, and so far its really impressing me. Dave Meyers is very smart and I am glad that he didn't just b.s. with me, he took the time to tell me why he would build the converter in a certain way. Hoping tog et some good seat time in during the fall, it pulls much harder. Make's me certain that it was all worth it.


Orr:
yea, I think the top end Mph is a combination of me not being wot, short shifting, maybe having only the headers and y-pipe on and no mufflex 4", and also I think I mixed in far too much of the ACES IV fuel additive. https://bndautomotive.com/aces-formu...oline-formula/ Dave was very supportive of this stuff for guys running nitrous and I ended up talking to the creator of this stuff for a long time on the phone. I think I eyeballed it and didnt increase any ignition timing as I was more focused on the launch stuff that day. If I had more passes in before ht rain, I think I would have added some timing, looked at plugs and datalogs, and kept more timing in the tune for when nitrous was on. Also, probably since I am on the rev limiter well before the finish, thats killing top end mph. But you are 100% correct, my previous n/a passes are usually 11.70's 11.80s at 116-117 mph (95-96 mph in the 8th) and the nitrous passes are generally 1 second quicker and 10 mph faster, with my previous best being 10.601 at 127.7mph (and 105-106 mph in the 8th) I am ready to redeem myself!



SkinnyZ:
yup! you hit the nail on the head many months ago by describing the benefits of a properly spec'd converter, and I thank you for that advice, big-time! I'm really digging the stall and less drastic drop in rpms between shifts! I'm going to post a bit more on that just below here. Not sure how I would calculate converter slip? and yes, I bring the little fella outside as often as possible!


This past weekend I wanted to get more passes at the track, but the remnants of Hurricaine Ivan came to Nj and basically the wind/rain was too much so the track was closed saturday and sunday. Instead, I put the mufflex exhaust back on now that I am confident that the converter/trans is all-good and I wont need to get in there. Did an oil change with valvoline VR1 20-50 and a filter. Took the car out for some fresh 93 octane Shell gasoline and did a dozen miles of driving. I plan on going to the track this upcoming Sunday for the Nostalgia Fall event, and they are tossing some vintage funny cars in the event since that "funny car reunion event" was rained out earlier this year. Therefore, I KNOW the track prep will be good, and I know there should be some good heat in the starting line. I have to make sure I get a good burnout in order to get the launches perfect. Not sure if I will do test and tune that day, or enter the N2 bracket. If I enter the bracket I would only run n/a, but Test-n-Tune I could experiment with nitrous launches.






so,


Anyways, here is a screenshot of my foot-brake stall during Sunday's little drive:

looks like I can foot-brake successfully to around 3,000 rpms and the old converter I could only hold 1800-2000 on a footbrake:




.


And here is a screenshot of me holding a steady rpm and then going WOT to see flash-stall, for this one I was almost coasting in 3rd gear at 2,000 rpms and went to about 3/4wot, where it zingged up to around 4,700 or so.



On this one, I was in 2nd gear, right at 2500 rpms and went 3/4wideopen throttle again and it flashed to about 4,800. I then stayed in the throttle, made the shift and this log also shows a real nice/tight rpm drop between 2nd-and-3rd gear. It used to look massive on the old converter, this is cool. Its right in the meat of the torque .





lets hope Sunday does not rain and I can get some track time in!

skinny z

You can use your MPH and RPM and reverse calculate it using your final drive gearing when you cross the line. That and tire diameter.
I use this calculator:
http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php
Then take your theoretical RPM and divide it by your actual and there's your percent slip. Your RPM will be higher than the RPM calculated if you input 0% into the calculator.

mw66nova

iTrader: (13)

Wallace actually has a converter slip calculator as well. takes some of the long math out

http://www.wallaceracing.com/converter-slip.php

Orr89RocZ

iTrader: (20)

oh thats 100% it then. I didnt realize that. Need a gear change especially if you are spraying it