Hello ,

I wanted to know if there was a way to gain power on my 5.7l TPI engine (Trans am GTA from 1991).
I have already removed the catalysts ...
Thank you
Mike

 

Yes. There is a way.

GD

 

There is lots of ways! Search the forum and Google... Lots of info.
Cheers

 

Hello,

I tried to search on the forum, the problem is that I am in France and I do not know what to write in the search engine.
Also on Google I do not find much on American cars ...
Thank you for your help
Friendly
Mike

 

There are literally so many ways we couldn't count them all.

It would help to have an idea of what your specif goal is to help point you in the right direction.

Some basics to get started that will help with any L98 based Combo.

Long Tube Headers, 3.42/3.45 rear gear, A good tune up, and scan tool to make sure things are running properly

 

Assuming your car is stock except for catalytic converters, here’s some basic things:
Basic tune up with new performance ignition coil, spark plugs and wires
New rotor and cap
Cold air intake kit
TPI throttle body foil
Under drive pulley kit
Headers
Performance catalytic converter
Cat back exhaust
performance chip along with cooling thermostat
Sub frame connectors
Wonder bar

that should give you around 40-50 extra HP at crank so around 30-40 at wheel. If automatic i believe there is less parasitic losses.
The sub frame and wonder bar will straighten your chassis for better handling and steering response

If you want more, you are looking at swapping cam heads and induction. Way more money and tuning involved

Cheers

 

Eh, that bang for buck is in the gear, headers, subframes, and wonderbar and toss a strut tower brace in there... though again what condition is the car in and where do you want to go?

The performance chip is snake oil until you do some changes and get a CUSTOM tuned chip.

Leave the thermostat alone. Unless you use a chip to exploit lower fan temps and more timing... it is just snake oil.


I can not repeat this enough, the L98 cast manifolds are so bad the LT1 Cast manifolds are considered an upgrade! Do headers and a 3.4X gear first!!!

Also consider a higher stall converter if automatic.

 

Good evening,

Thank you for your answers, so I will study all of this ... The car is original except for the catalysts that I removed.
It has 240 hp, my idea was to get closer to 300 hp but living in France and not having a specialist in American cars around,
I wanted to see if I could make modifications by myself.
Thanks again .
Friendly
Mike

 

Mike,

First off, that is AWESOME you have a Firebird in France! These cars are getting more rare here in the States, but in France, you're straight up driving an "exotic" piece of motorsport history.

I think an easy place to start would be what kind of budget. If money is no object, let's check it out:

Since your exhaust is now more free flowing, maybe look into an aftermarket air filter. That will help your engine flow better. SLP makes this kit:
https://www.ebay.com/itm/NOS-90-92-C...QAAOSwQJ9e3sNI

After that, look into cams: https://www.hawksmotorsports.com/sbc...ic-roller-cam/ This will also make your engine sound different.

If you want to keep modifying from there, let me know. We can talk about it.

Your friend,
Recovering

 

Good evening,
Thank you for your propositions.
So I'm going to study all of this and set aside a budget so that I can make some changes.
Thank you for "recovering" for your clarification on the trans am GTA I did not know that they were in danger in the USA.
It is true that we do not see many firebirds in France there are many Mustangs but I wanted to stand out.
Thank you also for the parts link
Friendly

Mike

 

How did you get on with the mods on the car I have a gta in the UK I’m interested in updating to 300 or so hp for a reasonable cost I have a feee flowing exhaust and hooker headers already .

 

Hello thirdgenuk,

So for now I haven't made any modifications to my engine.
The only thing that is not original is the catalysts that I removed.
The next modification will be I think an air box to get more fresh air from the engine.
Friendly
Mike