I have an 88 GTA Firebird. It has the 350 TPI setup. It has been modified, but still only does a 14.3 @ 97mph. The GTA's are heavy cars, but I've seen heavy cars run low 10's. My situation is that I'm thinking about selling my car. I love the way it looks so much and all. I don't have a lot of money right now, but I could save up when I get out of college to make it fast. I need to know if I should give it up and get a LSI when I have the $, or can the TPI in a GTA be made to be a real power house? I know the stock 3.27 gears, a stall conv, and a power adder are about the only things left for me to do. Below is some pics of the car. Please help in my decision! I will post a list of current mods if needed.

 

You can easily get it into the 12's, like they did in Chevy Hi Perf! Keep it and learn how to drive it better, then you can win by skill and familiarity. There's a lot of guys out there that red light with 10 second cars!

 

I'm not really sure what mods you've done, but it must be a lot since you can only do gears/TC and a power adder. Since you're only running 14.3, I'd say that there's a LOT more you can do. Right off the bat...you can get a new intake. I love the long tube setup too, and it CAN be fast, but you're losing all kinds of top end....even with oversized runners and manifold.
What kind of heads are you running? Heck, without knowing what you've done, we could be here forever, but my stock L98 runs mid 14's and I'm NOT a good driver. The L98 is easily capable of mid twelves without getting toooooo crazy. Sure, it's more than a set of headers and a chip, but don't let anyone tell you that you can't be fast.

 

Is that TPI powdercoated?

 

I have:
58mm TB with K&N and wide mouth intake
ported plenum and large runners from TPIS
Large TPIS intake manifold
Edelbrock ZZ9 street/strip cam with roller rockers
L98 aluminum heads off a vette (ported and polished)
bored .30 over with flat-top pistons (forged)
Bigger fuel pump, rails, and injectors
Hotter firing coil
transmission cooler, and bigger oil pan
Edelbrock "shorty" headers, with duel exhaust cats pulled (changing to a 3" pipe with cat)
slicks when racing
both headers and TPI are powder coated
That's about all I can think of right now. I believe that's all.

 

you can also do pulleys, custom chip, stroker kit, lots of suspension mods...u can do a lot of stuff still.

 

I just ran 13.783 with my GTA and I have alot less mods than you. It's all about matching everything properly.

I have unported vortec heads with upgraded springs, an unported SDPC TPI base with untouched runners, plenum and TB. I have the stock L98 cam, Edelbrock TES headers feeding into my garbage stock Ypipe(soon to be replaced), into a 3" mandrel bent exhaust(no cat) feeding a 2002 Camaro SS muffler.

Right now I beleive my Ypipe is holding back some top end power so I've only run 99.6 mph. But I beleive that when I replace my Ypipe and with some more chip tweaking I will be at the 102-103 MPH range.

Are you scanning? I was getting a lot of knock and was running 14.2-14.3s. After playing with my spark table to eliminate knock with 30-31 degrees total timing I ran my high 13s with a best of 13.783.

I am getting alot of usefull information from scanning and logging my runs via the ALDL port & Moates software. You can too.

The next investmant should be into an ALDL to serial adapter along with a old laptop to scan your car. Then setup to burn your own proms.

I gained .5 second on the same day from chip tuning. I am sure you can benefit from it as well.

 

I'd say your l98 heads are your bottleneck, stock ones don't even exceed 200 cfm on the intake, unless your absolutely sure they were ported and polished by a great port and polisher, they would be the downfall in the combo.

 

They're ported vette heads.

 

A TC and gears would definitely help you. Do know if you do much reading, but a while back CHP magazine did a story on a '87 (?) Iroc that ran 12's with the combo your using and the all ready mentioned gears and TC. I think there was a holley ignition in it too. You have a stout combo, that sounds like there is more in it. Have you tried a custom prom like poncho said? Hell if you sell the car I'll buy it, because there is way more left in it besides a 13.

 

you should be running faster than that with your mods.
but here's my suggestion.

PROCHARGER :hail:

 

Yeah, I do have a custom level 5 chip from TPIS, and March underdrive pulleys. I know I could still charge it, Stall Conv, and gears... but it should already be running way faster than 14.3.

I guess after the time and money and tuning that's been put into this car, it's a little frustrating to run only 14.3 when a lot of guys are running low 13's and 12's in only a couple of months and mods in mustangs. I guess that's all.

 

I'd hate to make a vague statement but something is wrong - I would first do a fine comb over of the vehicle to find where my half second is going to waste... cause thats about where you should be - 13.5 - 13.7

BTW, how far above sea level are you at when you go to whatever track you go to? If you are about 3,000ft or more then you can clip about .4 off your time as a rough adjustment. In Vegas LVMS sits 2,200ft above sea level and NHRA correction makes my 14.51 a 14.21... just for example

 

Yeah, let's focus on the real problem. Not what to do next, but what's wrong NOW. A "fast" stock L98 should be runnin' low 14's. No not all, but some are just faster than others. I think it's time to go over what you got now, before you go any farther. You should be WAY faster.

 

I am going to go out on a limb and say that you need a good lock-up converter to maximize your combo. Get some stall engine speed and I think you will like the results. I am considering Precision's Vigilante converter for my TPI Z28, it worked wonders for my Grand National. Good luck.

 

yeah
, you should be running low 13's if not better with the mods you have.

 

You have a combination that has some hidden problem that is holding you back. Your combination is very similar to my combination on my corvette and I was running 12.60's at 107 MPH. I had the ZZ-9 cam, large tube TPIS runners, Big mouth manifold, Trick flow heads, and TPIS headers, and a 2300 RPM stall, 350 CID, 52 MM throttle body, stock injectors. The vette with me in it weighs 3400 LBS. I would expect a slightly heaver GTA to run high 12's with the same combination. Check all the basics like intake restriction, exhaust restriction, fuel pressure at WOT, Look for a bottle neck.

 

How many times have you raced it at the track? The first few times I ran my GTA, I was in the 15's. After racing a few more times, I have a best of 14.4 at about 95 mph. That was stock with a K&N air filter. I would NOT sell that car, with what has already been done to the engine, and the shape it is in. You should definately be running quicker though. Aren't those TPIS chips expensive as hell?

 

Can you post all the times off the time slip? Like it was mentioned earlier there has to be something mechanically wrong with the car. I see you have had machine work done to the block, is it all the stock bottom end besides the pistons? What size injestors? What kinda shape is the trans in? There is something wrong with the car in a major way. I run 14.2@96 all day N/A with a 305 with stock everything besides a LT1 cam. One last thing how was the weather at the track when you made the runs, I see you are in Fa, it may be heat and humidity related.

 

somethins fawked up man! but id get rid of that 58mm TB, put ur stock one back on. lets see some time slips, im baffled! btw...just curious as to what ur base timing is set at, and do u have an adjustabel fuel pressure regulator? if so what is that set at?

 

His car is already in the TGO classified, I guess he is over it.

 

Thanks guys for all your help. I adjusted the fuel pressure, the timing, and coil. It is definatly a LOT faster!! I had no idea what a difference timing would make lol. I kinda felt imbarrased that I hadn't done it sooner. I unfortunatly do have to sell the car now though. You can find it in the classified section of this board. Don't worry, I will be an F-body owner again! Again, thanks for all the help.
-Blake

 

If you love the way it looks and listen to these guys, you will be glad you kept it when it runs high 12's low 13's in a matter of weeks.

And best of all your car is most likely paid off, whereas with an LS1, you'd be paying at least $4-500 a month for it for the relatively same performance.

So again, keep it, tune it, stall and gear it, and then love it!

 

??? umm.. you brought up this OOOOOLLLLDDDD post to comment on something some one wanted to do 2 years ago??

 

NO!


Holy $hit your right. LOL!! Well, I should definately stop going through thread pages. Geez, after the 89th page you'd think I would realize they were getting much, MUCH older than yesterday, huh?

I did a search and replied to the first thread I read. Muh-bAd!

 

Okay, now that was funny

 

91 GTA

only mods : SLP catback and 24# injectors

My own personal tune that I did

Best run:

GF driving and 2.3xxx 60ft at 14.4 at 94mph letting off thru the traps lol

Was hitting 97 plus mph with a 105 heat index


Dynoed as above 225rwhp and 315 ft lbs

later
Jeremy

 

just giving you a hard time..

 

I am running 13.5 at 99 with all the bolt ons. I got 245wrhp, and 325rw torque. So at the fly wheel its equal to about 306hp. Not sure if a bolt on L98 can get low 13's at least I dont think mine can. With your mods you should be running alot better than 14.2's. You should be into the high 12's.

 

What's your 60' times?If your not below 2.0 traction off the line is your problem.I'd upgrade the stock suspension w/ subframe connectors,better LCA's etc.Hell I'm running better times with my n/a 305

 

SEE SIG

 

Seeing as this thread has come alive again. See my signature.