I had 12 passes on Friday. Ranged from 16.0 to 15.6's

Engine - 350 bored to 357
Edelbrock RPM Performer Heads
1.6 RR, Stock cam, BBK 52mm throttle body
1.5/8 exhaust , flowmaster 50 series x2
24 lbs injectors.

I had the computer reprogrammed 1 month ago and everything seemed to run pretty good. But all the other TA were cruising right past me down the strip.

I keep hearing that I should be in the low 14's, but I couldn't pull that off with my motor, not even close.

ANy suggestions. Thanks

 

More info is needed. What year is you car ?

 

it's a 89 Trans AM GTA, with 5 speed manual. 3.42 posi in rear. This was the first night out but I was definitely getting my *** handed to me.

 

My 305 auto runs faster than that and its near stock!!! This may sound stupid but (no offense) do you know how to drive stick? Alot of people don't know when they are doing it "wrong".

 

Is your entire intake system stock. If so that is holding you back, but not that much. How much are you spinning. Is there a chance your clutch is slipping.

 

The clutch is brand new and doesn't slip at all. I have tons of spin if I want but I found that to get the best 60' times I had to start off alittle less agressive.

I can drive the car fine. I had a old chevy truck pull away from me at about 75-80 mph when were down the track, it had a stock 400. I was always able to get a good jump on the competition of the line and for the first 60' I was usually ahead. After that nothing seems so powerful.

 

Did you have the 350 installed? because you couldnt get a 350 with the 5-speed from the factory. And maybe its spinnin hard out of the hole. What are your 60ft times? I have a friend whose 85 305TPI IROC went 15.15 in the quarter with very few mods at the time.

 

Installed the 357 in Nov. kept the trans. My best times
1) reaction - .152
60' - 2.506
E.T. - 15.658
MPH - 88.450

2) reaction - .098
60' - 2.483
E.T. - 15.743
MPH - 87.403

I should taken more notes on each individual race but after 4000 rpm I lost lots of power. I felt that the tires may have been spinning a little much but I was getting better as the night went on. My ET's weren't getting better but my 60' best was - 2.369

 

I have a very close to stock GTA that runs very low 14's before the 2500 stall. I think you have some issues in the prom and the cam and itake are holding you back. I think a cam with a little more lift and duration( I have one I am going to put in my new motor that is said to put me close to the 12's, .458/.472 and 212/218 duration @ .050) and a stealth ram or slp runners and some port work would gain you alot. You have RPM heads but the cam and itake will not match the capabilities of the heads. You will actually lose power because the runners are to big not giving enough "vacuum" to pull in the air. If you read some articles in Chevy High performance mag or others like it, they will not use very big heads. The biggest I have seen on a motor like yours is 170cc intake runner. I am not sure ehat yours are but I think the RPM's are bigger. One thing you could do is buy the Edelbrock base and runners then do some port work to them as well as the plenum, like knocking the "walls" behind the throttle body done. Sorry for the long post everyone. If you would like to talk more about this this feel free to email me anytime, I will answer you as soon as I get it. Thanks

 

there some issues here that may not be solved by tuning alone.
my bone stock l98 with prom tuning hit 99MPH(95MPH before) in the 1/4 with all emissions and stock mainfolds intact. whats the actual compression ratio? roller block? what exhaust setup do you have? more details please.

 

Your 60' times suck. No offense, mine sucked last time I was out too. I was pulling 2.4x 60's and running 14.7s @ 97mph on a 75 shot. That MPH would've been good for 14 flats or so.

There's something wrong with your car though besides that. What was done to this "chip" that you had programmed? What have you changed since then? What's your fuel pressure like at WOT? Is the car pulling timing because of detonation? etc.

 

the compression with the heads should be stock, 9:1. The local TPI specialist here went for a ride with me in the car and changed the fuel curve until we couldn't feel and more power gains.

Exhaust is 1 5/8 headers and flowmaster dual 50 series. no cats.

 

Triple check everything mechanical and electrical.

Then get a wideband and your own tuning stuff. U dropped thousands on the car spend $500 more to do it right yourself..

Its well worth it in the end and will pay off for power and mileage.

Stock 91 GTA, had 24# SVO injectors and a SLP catback running 14.40's on a 2.3XXX 60 ft with my gf driving and she let off thru the traps and only clocked 94 in the qrtr.

Lots of power to be had doing your own tuning and investing in a wideband.

later
Jeremy

 

You need a T U N E!

 

Who built the engine, and what is the C/R. If the wrong pistons, with the wrong heads, and head gaskets were used, you can be down on compression big time. You gotta look back and get all the specs on all of this stuff. This happening is not rare. A guy builds an engine, to find out it has 8.5:1 C/R. BTW, get some sticky tires too.

Also take 3.8TransAms advice. You very well can be very rich, with little spark advance at WOT, that will also make the engine "lie' down.

 

What exactly is the "stock" cam you've got, I take it was a 350 swap into the car so what stock cam are you using? If it's a peanut cam or similar your power will be non-existant...

Also, a 2.4-2.5 sixty foot sucks, you can get down to a low 15/15.0 if you really cut that down to around a 2.0 60' with no other changes... But you're obviously really down on power if that is a low altitude track. Which I didn't see mentioned what track you running at/what the altitude/density altitude were but that can greatly effect your times as well...

 

better 60's will help alot. you might also be shifting late, the TPI intake/cam dont allow for much power after 4500rpm

 

Yep. That 60 foot is awful. Get some decent tires on there and look into tuning a chip for it.

 

first try gettin your 60 foot down

i ran a 1.97 60 foot and pulled a 14.1

next run i spun and did a 2.28 and ran a 14.7

 

Something is very wrong with your car.
Here is what my 86 T/A LG4 (165hp version) 5 Speed ran with a carb swap,


My 88 Formula in my sig was running 15.2 @ 89mph with only a gear swap from 3.23 to 3.73. I converted to a T5 and put the StealthRam on but haven't been to the track with that combo yet.

 

yeah but that was in virginia in late september...makes a difference

 

Has anyone looked at his trap speed? It is terrible, he just plain has no horsepower. No matter how bad his 60ft is he should still trap at least 95mph. You have a major tuning issue or something in the motor is messed up.

 

i was trying to say just that, but not so boldly.

 

I'm kind of having the same issues...it feels like more power should be there.

I recently swapped in an SDPC 360hp vortec tpi engine...put slp runners on and 24# SVOs...along with a holley AFPR and hooker 2055s. i have a built 700 and 3.42 rear. mind you when i ran it was damn near as humid as it could get, and 94 degrees...but i could only trap 86. then again my built 700 was holding gear until 6000 rpms..and it wouldnt shift until i let off the gas (the governor is set too high).

However, this was on a somewhat f-ed up tune...we retuned and it felt pretty good once it began to cool off. didn't get another chance to run it when it was retuned, due to rain.

i still feel there should be more power...any ideas?

 

Really? It morphed from an '88 S15 POS truck into an '89 GTA?

 

It was still warm outside though.
I did a cam and TPI swap on the LG4 with headers and full exhaust and ran a pretty decent time with ECM in limp home mode,

 

actually running a 15.7 @ 87mph is right on par with what i have when i dont get a good 60ft...i dont have a way to scan my timeslips on but here we go
BOTH RUNS ON 3-20
BAD 60' GOOD 60'
60ft - 2.4 2.079
594ft - 9.58 8.978
1/8ET - 10.22 9.611
1/8MPH - 69.54 71.08
1/4ET - 15.8339 15.06
1/4MPH - 88.43 91.09

were at 3700ft, on a good day DA is about 5200ft. so how do you figure that 15.7 @ 87 is terrible? the BEST i have done is 14.88 @ 92.98. A 2.0 60' time WOULD put him in the 14's

 

He shouldnt need a tune. Theres nothing above stock except injectors and a better set of heads to tune with. Get a stock TPI Maf 350 chip and put it in. Set timing to 6* and see what happens. I bet your chip is holding you back.

 

[B]

He can benefit from a tune. Larger injectors, better flowing heads all change the VE of the engine. The engine is probably just too rich, with a conservative SA. One thing though. GET SOME STICKY TIRES! Then race several more times, and get the 60 ft down. THEN, worry about the engine if nothing changes. I bet it will though. Then you can tune.

 

Its a MAF motor, he will be fine. I ran LT4 cam TF heads and superram with the stock 89 chip. Ran fine. Sticky tires wont help. There is no MPH

 

do you have the 1/8 miles times and mph as well?
post those if you do so we can see how the car looks halfway down the track.

And remember, MPH shows you HP, Low ET shows a good launch.

 

[B]

Yea, your right, I forgot he has a MAF. With the small changes he made, the MAF should have no problem correcting for it. Might be a bit rich with the #24s, if he is set up for #22s. Should not be that slow though.