Well I took my car to th local 1/8mile today and I am not pleased at all. Firs here is a list of mods.

355cid 10.1comp
afr 190s flowed 260ish int
cam comp her 276 224-230 dir @ 50 530-544 lift with 1.6 rockers
HSR intake port matched to heads
stock 48mm t/b
flow matched 24lb inj
new bosh maf with k/n on end of intake tube
custom chip// wot- timing at 34 deg
crane ign
msd wires, cap and rotor
headman shorty headers
flowmaster exh.
stock 3.27 gears
raptor 700r4 trans
2800 stall non lockup.

The bad thing is I had to run my drag slick from my race car which I new would hurt it a little but this was bad. They are 28x9x15 et drags

Best time in the 1/8 was a 8.87 at 78mph witha 1.92 60ft. The car was a damn slug out of the hole and finaly started to pull once I got out of the 60 ft, but the car just did not seem to go. It seems to run great driving around town and so forth though thats what is wierd

Now here is the other wierd thing I sprayed a 100 shot of juice on it and the damn thing went 7.69@ 90mph with a 1.69 60ft
That is a little much to pick up with a 100 shot with my previous exp with NOS.

Needles to say I knew the times would suffer with the tires but this is just plain bullshi@. I am going to have some diacom runs made this week and see what the hell is going on. I hope I can find something or I am going to freak!!!!!

ANy help here would be great.

ps my stock tpi with 188k on it had a 2800 stall, flowmaster, egr walls removed, and k/n and it went 8.82 in the 1/8 at 78mph with slicks! and only went 8.10 with a 100shot.

Drew

 

somethings not right dude...... that thing put's out some hp...

dd2000, gave 482hp at 6000 and 469lbs at 4500 rpm........

more than enough for low 12's high 11's

with a 2800 stall and slicks you should have been getting 7's in the 8th....

and nos, fuuggedabout it......

are you sure you got traction??? you will defanantly need the tests........

slipping tranny???

 

Dude, your running 28" Tall tires with 3.27 Rear gears.



No wonder its a slug out of the hole. All your ET loss is in that 60'

The reason you got so much gain from the N20 was cause spraying off the line got you out of the hole way faster, with that compression ratio the nitrous is going to build massive low rpm torque to get you going.

That would be my guess, anyhow.

 

You probably need to bring the timing in earlier. While tuning in my MiniRam, I found it to be much stronger out of the hole by having total timing in by 3200 rpm. I also increased timing below 3200.

www.goecities.com/dzperf

 

I'm with Bort. 3.27 gears don't seem steep even enough for your combo with regular size tires, but then to add some 28" slicks with them has to be killing it off the line. I think some 3.73's are needed.

 

I understand the tires are to big. I knew that going to the track, but do you guys thing it would have hurt me that bad. I mean my mph was slow as ****. only 79mph?????? I am going to get some 26x10x15s soon. I just used my 28's cause they are brand new and my race car is taking a nap for a little while.

My timing is at full 34 deg by 2800-3000. I am also thinking need 36 deg at full throtle and not 34.

I appreciate anyhelp here this has got me mad and I will be at bristol this weekend for the year one bash. Anyone else going?

Drew

 

I'm with you there. I am having similar woes. You do need more gear, especially with 29" tires. I run 26" DR's & 3.89 gears & it still runs the same 60' times as with my old setup. I had some lean spots on the datalog & attributted it to the 22 lb injectors. So I put in 30lb SVO's & reset the advance to be all in at 3000 rpm, 38 degrees total. Check this thread out for my times, before & after the HSR, AFR's & cam. I am planning to go back to the track this Saturday to see if there was any improvement.
https://www.thirdgen.org/techbb2/sho...&highlight=HSR

 

I'd vote for tires/gear being the main problem as well. Bogging it to death off the line like that, as well as the drag of the big gumballs the whole way down the track could easily be stealing a couple mph from you.
Other than that there's always the chance you need a lot more tuning too. You seem very fixated on total timing. Did you even play with your fueling at all?

 

with those tires, your gear ratio is reduced to 2.99...i'd say that in itself says a lot.

A 2800 stall converter with 2.99 gears is gonna dog it out of the hole, and it's not enough gear for you to shine in the 1/8th mile either. You're gonna barely be warmed up in 2nd gear and you're going through the traps with your current setup.

And your combo i'm assuming is meant to build it's power in the 3000 - 6500 rpm range, correct?

If you're shifting at 5000 or something, of course you're gonna be slow as all hell. are you letting the car shift itself or are you shifting it? because a good theory as to why your nitrous run was a LOT better is that with the nitrous added power beating on the tranny, it shifted at a higher rpm from 1-2 which was drastically to your advantage if you were shifting far too early.

 

Despite the lazy gears and tall tires, 1.92 isn't a horrible 60'.
I don't think the launch is killing you.
The gears and tires hurt the rest of the run more, probobly keeping you out of your powerband.
Like mentioned above, try shifting higher. Overrev first a little so the drop to second won't be as bad.

 

1.92 *IS* a horrible 60' time for a 12 second car. He should be turning at least 1.7s if he was taking advantage of his power, if not better.

 

I agree its not the best 60, It could be alot worse however, and that would better explain the ET. I think he should be able to turn a better ET despite his launch, that is what I meant. The trap speed is also low. If the car has the power to turn 12s, it should pull a better mph.
For a loose comparison, here is one of my time slips.
I had an even worse 60' of 2.09 (street radials)
though in the 1/8 i ran a 8.55 @ 83.
For a 12 second car, his trap speed would be what worries me, not so much the et. either he's not making the power, or the gearing and tall tires are killing the run, which we all agree that they are.
I think they hurt his mph more than his 60' though. And if that's not the case, then the power isn't there.
He's pulling the same mph as his old setup, I'd say something's amiss.

 

Here's what i'm saying though. That tall combo is basically bogging him to death off the line. If you figure the tune is a little off it's really easy to see how it could just not make any et or mph all bogged down.
Especially when you factor in the relatively extreme traction for the power level. Tires cost power. I'm really leaning towards drag radials being one of my main 'problems' my last trip to the track. I was cutting consistent mid 1.8 60's in the spring on regular tires, and running in the low 95 mph. Now with a siamesed base, running much stronger IMO i could only do mid 1.9 60's and high 94mph. I was running the drag radials at 26 b/c the track was packed so i didn't want to lose time getting air. Next time i'm trying more.
But the point of that long anecdote is, sticky tires are bad when coupled with a handicap like a 305 ortall tires and 3.27 gears

I figure he's off at least 2 tenths on his 60' alone. And 2,3, hell even 5 mph wouldn't be outrageous for letting the car run it's powerband. And thats not counting the tune once again. If it was my car i wouldn't take it to pasture and shooot it yet, lol.

 

Yeah I played with the fuel press a little about a 2-3 lb increase and it did nothing at all. ran the same. I am going to put my 9in with 3.70s in this week and borrow a set of 26's from a friend and see what happens. I am going to doa diacome run tomm night and see wahts going on as well. I am not to good with reading the numbers and what I should look for besides o2 voltage and knock retard though.

Drew

ps thanx for the help

 

I was shifting at approx 5500-5800 all motor and about 5800-6000 on the bottle runs. Right at about 6000 the car seems to fall off a little so thats why I decided to shift at the above rpms. I manually shift everytime.

Drew

ps thanx for the help.

 

I would like to say thanx so far for the replys. That is why I like this board people are always willing to try and help.

Drew

 

Something is way off if you're noticeably falling off at 6k. I'd think you could get a little more out of it than that.

An interesting thing to check on would be the MAF reading. Perhaps you're maxing it out. Or perhaps it just doesn't read rigt at high speeds.

 

What type of converter do you have?

 

Ed, I see what you're saying. It just bogs so bad there's no chance of making it up throught the top half.
I thought the maf didn't have an effect at wot, so how it reads shouldn't affect performance under full throttle??

 

I'm running a similar combo with the same cam & valve float above 6k is a very distinct possibilty. That cams powerband is 2000-5600 according to Comp.

 

I think its just valve float. Hyd Rollers dont like going above 6 grand unless you have a stout sprind or a rev kit. The springs that come witht he afr 190s are ok just not able to keep up at high rpm.

The one thing that worries me is my mpg more than my e/t. I can understand getting killed of the line but 78 and 79 seems way off. Or is it just that since I was bogging off the line I am now playing catch up like what was said earlier.

Drew

 

I am running a 2800 stall 10 in converter non lockup.

Drew

 

You know, I doubt the problem is gear ratio related. I’ve got a very similar combination (355, HSR, 2500 stall) and I’m pulling 1.80 60 ft times with a TH350, 3.27 gears, and 26” tall ET Street tires - no bog (totally stock 144,000 suspension). My effective gear ratio with the TH350 and 3.27 gears is 8.27 (2.53 x 3.27). The effective gear ratio for a 700r4, 3.27 gears, and 28” tires (compared to 26” tires) is 9.27 (3.06 x 3.27 x 26 x 28). I'm not saying moving to a 3.70 gear with your combination won't help,, it will with the RPM band of the HSR. However, I feel something is off - probably timing and or air/fuel.

Don’t know how much this will help, but I’m running a stock 1988 350 chip (22# injector constant) with 24# SVO injectors and I have the base timing at 16 degrees. I’m probably getting better air flow with the gutted MAF, 52mm T/B, and “cold” ram air induction. However, if you’re burning your own chips once you get something close minor fuel changes (especially with an AFPR) should be relatively easy.

On a side note,,,, I’m very pleased with the HSR performance - and that’s comparing it to a fully ported and custom length SLP induction system it replaced.

 

Well to me it sounds like your converter is killing your track times. As per your example it sounds way to tight and inefficient for running normally aspirated. I think once you get the 3.70 gear installed, that should help, but I think most of you time will come when you install a good converter matched to the new combo. IMO, a Vigilante TC in a 2800 would be your best bet. With your modifications, this converter would probably flash to 3000 NA and possibly a tad more on the nitrous. Your sixty foots should be easily low 1.7's on motor alone. On nitrous I would expect low 1.6's possibly 1.5's. Also, why a non-lockup?

 

I am runninga 2800 stall now though. The only diff in the vig and mine is a10in versus a 9.5 in... I run non lock up because I have had better luck with them. The price is also better.

Drew

 

 

Depending on what brand your converter is, there could be a big difference in it compared to a Vigilante or other high end converter.
What David was getting at is that some converters are way better at putting your power to the ground than others, they describe this in efficiency %. This can really affect your mph.
IMO, I'd still be looking at tuning more than your 60'. It just seems like your underpowered.

 

hey nosfedgta.... if the engine doesnt work... ill take it off ur hands... dont worry about it..... just give it to me... all ur problems will be solved.. dont listen to the other guys... they just dont know what there talkin about... what u need is a nice 305 tpi.... we can trade? sounds good to me.... hehehehe

 

As 87 FakeIRocZ mentioned I'm actually trying to point out that some converters are much more efficient than others. Most people go the cheaper route on a torque converter only to find dissapointing 60 foots. With the right converter matched to the applicaton such as yours, your 60 foots should be well into 1.7's possibly 1.6. Another area to look at is the torque multiplication factor. This is what makes the car launch. The Vigilante, Yank, ect. all have outstanding torque multiplication factors. Again, from the sound of it your hp is there....just not getting transferred to the ground. Good luck!

 

Don't forget the basics. Holley openly admits that low-end torque is lost with the HSR induction system, and according to their dyno testing, the stock TPI is better for torque up to about 4,400 RPM. Sounds like you need a really tiny converter to make up that kind of loss...

There's nothing wrong with the traction and gearing theories, but don't overlook the powerplant. Then again, I'm only a 13-second guy.

 

Thanx for the help so far guys. I am on my way this morning to put my ford 9in in with some 3.70 gears.

For the converter I am running it is a Pro Torque 10in 2800. not cheap either. its not as much as the vigilante but it is up there. on my old 383 which had afrs, super ram etc the car went mid 1.60 60ft times with the converter and would occasionaly pick up the left tire about 2in.

I hope the gears and some 26in tires help me out alot. I will find out this weekend at bristol.

Drew

 

Pro Torque is one of the "good ones", so I've heard. Those were some good 60' you were pulling before.
Can't wait to see how the gears and tires help.

 

Well its official. I hate cars!!!! I put in my ford 9in with 3.70 gears and my 26x10.5x15 tires and did not pick up ****! I went to bristol and went a whoping 13.90 at 97mph!!!!!!!! wtf is going on...... I sprayed it and went 12.50 with a 100 shot!!!!. my 60ft was in the 1.80 range. I have no idea what else to check. All know is that I am pissed. the diacome is not showing any bad knock, my o2 seems to be reading fine. Its about 850-900mv wot. For know I just dont know....

Drew

 

Hmm, I might be tempted to put a vacuum gauge on the plenum and see how hard the engine is pulling on the MAF. Looking at the setup I see the MAF as an intake restriction and the 24# injectors as a fuel restriction (good to ~326HP). From the injector PW's you should be able to calculate the amount of fuel being injected. From that the HP level.

May explain why the larger-then-normal HP increase with the funny gas. Bypasses both restrictions.

RBob.

 

Drew,

I’ve worked on performance cars for a number of years – usually the cars that people have trouble getting to run right. I’d rule out the big stuff first and do a compression test on the engine – preferably a leak down test. How the plugs look coming out usually gives a pretty good indication if something is wrong. If that checks out, it’s probably a combination of things.

There are a few things that if off can cause pretty serious power losses and still look good scanner wise. One is cam phasing. It might be that the cam is retarded - that could explain for the lack of low end power and why the nitrous is producing about 20% more power than it should for you. Did you use a new timing chain and degree the cam?

How much preload are you running on the lifters? Did you set them with the engine running? If you’re falling off at 6,000 rpm, I’d suggest going 1/8 turn for lifter preload – that’ll help if you’re having a lifter pump-up problem,,, which is possible.

Did you use the stock timing chain cover and balancer so you know the timing is “really” where you think it is? If you used an aftermarket cover, timing tab, or balancer, did you set the tab on zero with the engine at TDC? The HSR likes more initial advancement than my old LTR set up – 16 degrees compared to 10 degrees.

Another area that really effects power for the MAF cars is the air tract. I picked up over .2 seconds by gutting the MAF sensor and another .25 seconds by running a home-made ram air system – almost half a second for labor and $18 from Home Depot.

I wouldn’t get discouraged yet. If nothing is mechanically wrong with the engine you should have a minimum of 1.5 seconds hiding in that combination.

 

I used a new billet timing set from rollmaster. The cam went in straight up dot to dot.

I went a 1/2 turn with the lifters when I set them.

I used the stock timing cover and tab. I bought a new oem balancer also. I put the motor at tdc and made sure it ws a 0 on the timing tab.

I have a custom chip from dave emanual. My initial was 6deg for the advance curve that was in the chip. Total was 34 deg. I bumped it up to 8 deg initial to get a total of 36 deg at wot. All my advance is in by 3k.

I took the screens out of maf and have an open element filter on the end. I ran no filter when I raced.

i will try to get a compresion test and leak down to see if anything is there.

Thanx for teh help.. I appreciate it more than you know.

Any other ideas?

Drew

 

Don’t get discouraged. When you make a lot of changes at one time and it doesn’t run to expectations --- you pretty much have to take one thing at a time and rule it out,, or fix it.

I’d say do the leak-down compression test and see what’s going on there. Even if leakdown is “OK”,, post your cranking compression reading. It can tell you a number of things to look for depending on where it’s higher or lower than it should be for the combination you’re running.

 

that sux, I was hoping the gearing would help some.
How were your 1/8 miles compared to the last ones? any improvent there?
Just start going through stuff with a fine tooth comb. Eventually you'll run into something thats not right.

 

my 1/8 mile times were right around the same. 8.80's.. i jut wish i had a little more knowledge on what else to check. I am going to do the compresion check next week some time. i just hope all goes well there. Then i will just have to see what else to go through.

Drew

 

I did the copression test today. Here are the numbers.

I will list them by cylinders

1-- 152 2-- 150
3-- 150 4-- 160
5-- 152 6-- 152
7-- 150 8-- 178

The seem ok to me but you tell me....

Drew

 

Are you sure you tested #8 the same way as the others?

If so, then #8 is a 18% difference between the lowest cylinder.

Does it fall on it's face above 6k?

What lifters are you using?

What exhaust?

Do you have access to your .bin file?

 

Are you sure you tested #8 the same way as the others?

If so, then #8 is a 18% difference between the lowest cylinder.

Does it fall on it's face above 6k?

What lifters are you using?

What exhaust?

Do you have access to your .bin file?

 

Drew, please verify that #8 is not a typo (148?),,, or as 89 suggested that the throttle opening was the same for all tests before I spend a lot of time typing what to check for. Thanks.

Kev

 

Nope not a typo. All the numbers are correct. The only diff is in the amount of time it took me to do them and when I got to eight is quite a bit later than the rest. Not to sure how much lifter bleed down affects these tests...

I am using new gm oem roller lifters

Headman 1 5/8 headers with 3 in flowmaster

Yes after 6 it does not pull anymore.

I am going to do some diacome runs today and I will save them.

Drew

 

I have a few diacom runs if anyone wants to see them. I can e-mail them. I am not to good are reading them and fully understanding whats going on yet. I am learning though.

Drew

 

If you can send it as an excel or text file, I will take a look at it.

micdoctr@yahoo.com

Is it a full throttle run? Send me one of those.

 

First, I’d run the car for a little while then recheck the passenger side bank starting with #8. It’s possible a lifter is bleeding down – rule that out first. With the plugs out,, see if #8 looks “wet” (oily) – could be a vacuum leak from the bottom of the intake. But recheck the compression and see if you still get a high reading on that cylinder. If so,, I’d get the car ready to crank, get it running and spray some carb cleaner up top around #8 port to see if there could be a vacuum leak up top of the intake manifold. Spray where the plenum joins the intake on #8 and #4 also just to make sure. If the engine idle did not change, I’d pull the valve cover and measure the amount of thread showing from the top of the stud to the nut, or if you have lock nuts, gauge how deep the Allen lock is for both the intake and exhaust (they’ll be different). If there is a significant difference between any of the intake or exhaust, readjust the rocker arm with the engine running. If there is still a significant difference then make sure the pushrod(s) are not bent or a different length. If all the intake and all the exhaust are the same, then the cam is OK - or a stud is not working it's way out - which could also cause a vacuum leak. If all that checks out OK my vote would be an intake leak from the bottom. Holley has or at least did have a problem with the intake flange being slightly warped (on the driver’s side though) and at least one person has reported that the machine angle wais bad on his - the angle was OK on mine though. I know Wieand (Holley) has always had a problem with quality control and I’ve had to have a number of Wieands resurfaced / machined. My StealthRam was slightly warped and borderline whether to machine or not. I did not, but it has presented no problem for me.

Still,, even with any of those problems,, fixed it’s not going to give you .8 seconds (or more) in the 8h,, and that’s about what you’re off. It’s probably a number of small things that add up. The only things that really jumps out at me is I picked up about .25 with a homemade ram air (over just a gutted air box) and I think you’re really hurting with the open filter at the radiator – there’s probably a good bit hiding right there. Also, I’m running 16 degrees initial timing with a stock 88 GM 350 chip – the customized SLP runners liked 10 with this chip. Single planes like a lot of timing down low. I’ll drop you an e-mail so you can send me your data runs – I’ll see if anything jumps out at me there.

 

Thanks Badss. I will check that. The one thing I noticed on diacom is when I shift I am dropping like 2000rpms versus a friends run who is only dropping 1000rpms. He has 3.23 gears and I have 3.70 gears. Now that does not seem right at all....I wonder if my converter is going away.>?< along with my other problems,

Drew

 

Drew,

Just read through this and had a couple questions....

Are you maxing out your MAF sensor?
Is this the stock bottom end or all new?

My HSR equipped ZZ4 w/mild ported Vette heads and a cam very similar to yours(.509/.528 222/230) is turning 13.77s @107 with a little tuning. I have a crappy GM Corvette Convertor and was getting 2.3 60s on street tires. I also nabbed 288 hp @ 5100 rpm on the dyno(my max should be higher I think...so I think I have issues too...) ON the dyno I noticed that after the convertor locked up I was getting much better power to the back tires...so I started locking my convertor very early. I gained 20 hp and 20 ft-lbs...you can check the dyno chart out here...blue is unlocked, red is locked.

[350 Dyno Run]

Click on the dynorun902.jpg link. Geocities won't let me link to it directly.

I see that chart as a testament to crappy convertors and how much power they rob.

GregF
87 IROC

 

Did anyone question the 48mm TB?

I believe they can barely flow enough
to feed one of the HSR intake ports.

Another possibility that would show
much improvement on the juice..

mike