we presently have 28 x 10.5 x 15 slicks, TH350 tranny, 4.33 gears 9 inch , 355 ci small block, 85 camaro which is stripped out which sometimes uses 175 - 210 hp NOS our best NA run was 12.6 - and our best 60ft was 1.663 - there is still some tuning in the suspension as its unloading after the initial launch and fishtailing slightly - the 1st and 2nd gears run quite long - with 2nd gear going well past the 1/8 probably nearer the 990 - and the overall snap between gears seemed quite soft after initial launch - The snap improved with a timing advance to 35-36 which made the engine more responsive with the combo but I feel we are overcompensating with timing for a weak overall gear ratio I use to run 26 x 8.5 x 15, 700R4, 4.10 10 bolt, with the same 355ci - we would run 12.0 - 12.1 all day NA with varying 1.6 60 ft times - With the old combo the 1st and 2nd gears were strong sharp and quick and we would be in 3rd by or just after the 1/8 I am contemplating a gear swap to get me to repeat my 12.0 and maybe 11.9combo NA Do you think a two teeth step up on the gears to 4.56 is a good increase in ratio over the 4.33 (given what the 4.33 is giving me now) - or should I go further try the 4.71 which I recently discovered is an option gear for the 9 inch - a 33-7 gear set ?? I really dont know what it will do on nitrous - but on the old combo we got 11.169 on one pass where I lifted off before the end - and a 6.944 1/8 best - same pass The engine will do +7400 - whether its making power there I dont know - but it usually runs strong right through 6500 up to 7000 what do you think - is a 4.56 cog of much effect over 4.33 given what I have been experiencing

no ideas - tips on what I could be looking at or try??

If you are using spray I would not add more gear. What about your converter and is the trans in good shape?

sounds like a converter or trans issue...i picked up ET after swapping from 700R4 to TH350

your combo is somewhat like mine....
what is your 1/8 et & mph on motor alone?
what kind of heads/compression does the motor have?
what kind of converter are you running?
whats the suspension setup?

Most of my combo's info is in my sig ;
355ci TRW-L2252AF forged 11cc dome pistons World Products iron 2.02/1.6 milled to 60cc - we figured it should be 11:1 if not above

ProSystems re-worked 650DP, Victor Jr , Crower sld 244/250 -.503"/.518"-106*

I run a TH350 (freshly built with manual v-body) and a Protorque 8in.converter

stock setup - boxed stock control arms and panhard bar using steel plate
+ subframe connectors

I dont have a 1/8 time yet on new combo - just the 1.746 60ft and 12.691 1/4 e/t came up on my slip at T&t weekend

I did get a 1.673 60 ft later in the evening - but the car fishtailed slightly just after the 60 ft and lifted off and stepped again - that got me a 13.022 1/4 et

sounds like your shocks are weak and bouncing back up too fast instead of squating and slowing rising back up. What stall is your converter and what rpms are you turning when you cross the finish line in the 1/4? that will tell you if you need more gear or not.

yup, but i think the first 2 things i would do with that car is get a torque arm and relocation brackets.
my car is really soft launching on motor i am getting 1.55 60's. the converter just does not work well at all unless im spraying it. 1.32 60's with 125 shot.

although that 9 inch cost more power to run, I couldn`t see it killing that much et. The new traction problems are understandable, the weight of the 9 inch over the the 10 bolt is considerable and I had to change my shock adjustments also to control the extra weight. what are you using currently? you could try some comp engineering three ways set to 50/50 and no sway bar with a bag in the passenger side for cheap... pinion angle and relocation brackets also change instant center points and can be had for not a ton of coin too.
If it were me I would be looking at the trans first, converter second. Your gear ratio is perfect for 28`s IMO...you should be trapping 68-7,000 rpms with it and a good verter... Going to the 4.56 or .71`s will cause more tire spin in the 60` I`d bet it would help et but not with your traction problems at the bottom end. Are your rpm`s the same at the traps as they used to be with the old combo?

I don’t know why you’re so surprised that it’s leaving softer, between the taller rear tire and the smaller first gear, you just dropped your effective first gear ratio 25%, you’d need to run 5.41 gears (donno what’s available in that range) with the 350’s first gear and a 28” tall tire to get it to leave as hard. Even if that wasn’t the case, the shifts won’t feel as aggressive because you don’t have the extreme rpm drop between gears that you had with the 700.

If it was me, I’d probably run a looser converter in the 350 to cover up some of the lack of gear in first, but for the most part I wouldn’t worry about it, you’ll run fastest with the gearing optimized for the times you’re running… In other words, figure out what RPM you want to cross the line at (usually a few hundred over where your hp peak is, a little bit over where you shift when you run fastest), estimate what mph it should be capable of running in the ¼ (I usually add a few mph just to make some room for more power), and then choose the gear ratio that will get you to cross at that point.

Crossfire - I figured out as much - I used a TCI calculator for optimum rear gear - and got 4.579 - using 28in as tire height, 118 mph, 7200 rpm, 1.00 trans final gear ratio, and 11 % slip not sure if my inputs are right - but its a good start I hope

my buddies have a 4.56 gearset as a spare for their car - so we figured we would put it in - see how it runs - so we are doing that as we speak and do a back to back with the same stock suspension setup

I am planning to put some suspension upgrades in the near future - trick front springs, 90/10, 3 way adjustable rear shocks - and a single anti roll bar from Wolfe Racecraft - these have all been ordered but will not be here for a couple weeks.

I will keep you guys posted - I am heading to a dynojet facility which was recently set up on island

I will decide on the way forward when we get some results from the dyno and another few passes on the stock setup

Thanks all

sounds like a step in the right direction... 11% slip is a lot, but that will give you some room a the top end...

Simply put, you have a serious, serious convertor (almost sure that is the culprit) issue and possibly a tranny issue. With your combo you dont need anymore gear...you get your convertor/tranny issue fixed, you will be plumb out of rpm when using your juice-I promise, and you will see if you get these things fixed.

A loose convertor will take alot of the hit away on the shifts, they just do that due to slippage, most guys get all bent out of shape thinking the tranny is going south when in fact it's just the convertor "absorbing it". Who makes Protorque convertors?? I've never heard of them, and am imagining this unit was cheap-meaning under $300. If so, beg/borrow a convertor from a fellow racer and I bet you will have a different car...I've seen too many of these cheap convertors hold cars back from doing what they can...and yes, convertors are everybit as important as heads when your trying to go fast quickly/effeicently.
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Also, for giggles, have you put a timing light on the motor to see how timing is acting when at idle, holding at 3-4 grand...is it jumping around or is it rock solid at where you have it set at when it's all in? Are the internals of the dizzy all in good condition? The same motor that gave me the numbers in my sig came out running consistant 12.00 passes every pass, we knew something was wrong and the dizzy was the problem, 1st pass after swapping it out for a new complete unit netted a 11.23...timing is that drastic if not right.

IHI - I sent the converter off today for a general check and a stall check.

Cheap is not I would call a $850 converter. It is an 8 inch converter by the way. They are an outfit that was recommended to me in the new york area - they do a lot with the 4th gen / grandnational scene and seem to be pretty good. They have a website protorque.com

We went through a whole lot of info before ordering - they seemed to be on the ball with queries

I would feel better if they found a problem with converter rather than I just got a mismatched converter

I agree that the 1-2 and 2-3 shift is almost seamless when I was using it - probably a result of the slippage you mentioned

I really thought that by going to an 8 inch with the TH-350 that I could get a better/higher stalling converter near 4000 rpm like as I DO NOT have a transbrake without loss of efficiency - to get me over the loss of the 700 R4 deep 1st gear


Your distributor observation is a really on the ball - I was just about to do a new thread on this - I dont have a dial back - but when we did the timing light on full advance - it was jumping between what I thought was 35 and 32

Its a MSD pro billet 85551 - not more than 6 months actual usage in race trim

Do you think I need to get it checked - the only mod I made to it was to install the 2 lightest silver springs

I intended to go back to the 2 heavy springs and see if that was the problem

will keep you posted anyway

I was just wondering about the convertor company, seems to be more and more of them popping up every week you paid good, so hopefully they are good...you can get it tweaked (most reputable companies let you run it first, see where it's at, then offer a free "tweak" to get it where it needs to be for a final product. Either way, what did the convertor flash to? meaning when you actually were at the track and then went WOT where did the tach needle jump upto and hold for a split second?? THIS is your true convertor stall speed...NOT what you can foot brake to, big misconception and I dont mean to insult you if you know this already, I just hear about that phenonminom waaay to often so figured I'd throw it out there. If you have a transbrake you can find true stall speed by pulling the staging chip, hitting the transbrake button and going WOT for a second to see what it reads. FWIW, I run a 10" TCI, the way it's set up I can "footbrake it" to 35-3800rpm, depends on air that day, but it will flash to 5K on the hit....so you could call it a 5000 stall, but it was "rated" at 4600, but it was right where I needed it to be regardless.

The dizzy, if it's jumping around THAT much there could be a number of things happeneing. First and foremost, grab one or maybe even 2 other know good timing guns, standd timing lights or the advanced timing lights, it wont matter...but double check agains the gun you seen the timing variation with first and foremost before moving on. If timing is still acting funny, I would ask what type of plug wires are you running? We've had trouble in the past with the thick racing wires Moroso Ultra 40 wires to be exact, they would give us funky readings and we concluded it was the insulation and wire wrapping throwing it off, so we have a standard, regular ole OEM plug wire we use to set/adjust/check timing, then put the race wire back on when we're done. Just another quick simple idea/thing to try.

Check for the typical arching/shorting out just cuz, seperate 5 and 7 wires best you can since in some cheaper wires and high output ignitions they like to arc since they fire at the same time basically.

If it's still jumping around that much you can pull the dizzy out, pull the cap/rotor off and take a good look at the bushings in the end of the centrifical weights, make sure they are still in place, and not cracked. There will also be some glides that these weights rest of (kind of a white plastic "button") check to see that those are still in place-mine was missing both and both bushing were toast as well. Check the end play to make sure there is'nt excessive slop in the distributor shaft by moving it up and down. If this feels tight (I dont know clerances off hand but it should be snug) check distributor gear mesh pattern to be sure your getting full contact against the cam.....if cam is'nt secured in place or has excessive movement the cam will walk forward, but that usually leads to a big problem with skipping a tooth and throwing everything out of whack...not just jumping a few degrees when checking timing.

Hopefully it's one of those simple things, the numbers just aint jiving on the track for what you have in the car....Unless it's an 1/8mi car I've neer seen anybody use that short of a tire and that high of a gear unless they're trying to spin some little storker to the moon by the finish line....good luck and keep us posted.

Josh

Protorque is a decent co…

Wow, looking back at your original post I think I missed the fact that you lost over a second in the ¼ there… IHI, good catch there. That was something that was bothering me with my response, that with faster cars, a “softer” hit with a higher stall speed and not as steep gearing usually results in a faster, easier to drive car.

Just thought I would UPDATE on my combo tweaking

CONVERTOR:

Well I sent out the 8 inch convertor for inspection and tweaking of the stall by the makers Protorque

They said the convertor was in good shape and they tweaked the stall as much as they could without affecting efficiency

Installed it - Now I can foot brake to 3000 (thats as much I was willing to try at the test and tune -as track was not well prepped) so thats a significant improvement over what I had before where at 2000rpm the body of the car would start torque twisting up on the rear right side before pushing through the brakes

So I have made some improvements there

REAR GEAR

I swapped out the 4.30 gears out of the 9 inch for 4:56

I now have a stronger 1-2 shift feel and a better response through the gears on the passes I made

With 28.5 x 10 x 15 - and the TH350 - I still feel that it could take a notch more gear - to keep the engine up in the band like the 700R4 did on the 1-2 shift

I think there is a 4.60... something gear ratio I saw in Jegs which I am willing to try or a 4.71 but my friends say they are happy with the response of the engine for now

FUEL PRESSURE GAUGE
I took this suggestion that I might be laying down with fuel pressure in middle of track and bought new Autometer gauge for on the hood placement and a new small gauge at the carb for cross referencing when setting pressure

Holley Blue and regulator holds steady at 8 psi but there was some slight bobbing of the pointer between 7 and 8 pounds in the late part of the run

I cant really take set it up past 8 as it is rather constant at idle and I dont want to flood the carb

RESULT

My comeback NA pass on the 4:56 gear turned out a 12.355 which is some improvement over the 12.6 passes I was getting on the 4.30 gear

I will try to tune from here with timing and launch settings to see if I can get back to 12.0 or even better

Then I will be bolting up the bottle for a 175hp pass and will keep you posted on the results

Thanks for all the help so far