Thread: Time for a spring tune-up and some basic mods

I have a 2002 GTP with 109,000 on the clock. The motor has all new intake gaskets upper/lower, valve cover gaskets, a new MAF, fuel filter, brakes/rotors, and some other minor things.


The weather is getting nicer and I'd like to take my first jump at some basic mods..I ran the car 100% bone stock at the end of last season and it went 14.6 @ 94mph.

First I'd like to drop the tranny pan and change the filter/fluids. + add a drilled 180* t-stat

Next, I'd like to change out the plugs this oil change and go a heat range colder, 605, or would going 2 ranges colder be a better bet to the 104's? Keep in mind after a small list of things I'll be adding a 3.5" pulley, so maybe the 104's would be a better bet..

I'll be adding a FWI made by me of course. I'd like to get a the front PLOG but they seem to be out of stock. I've looked into pacesetter and getting them welded but this is my DD..if I went that rout with the pacesetters after everything is done I'd prob step down to the 3.4 and skip the 3.5 drop..

If I can find a plog I'll be getting a catted 2.5 in DP..I've looked into the 1.9 rockers but I'll have to pay labor on an install like that..also I've looked into the blower porting offered here but im not sure how deep I want to dig into this...If I can I'll get a catless DP and keep my stock one 'just incase'..

Lastly right before the pulley drop I will get the car tuned..then throw on the 3.5"..

Sound about right guys??? This is my DD and the car see's about 28-31mph on the highway and around 21mpg city if I dont boost it too much

One thing that does bug me is the way my car sits..It just looks funny so I've looked into some basic springs to drop the car but ehh it's just my DD..saving for a c5 zo6 Vette for the weekend beater. Please and thank you for any advice you can give me!!

P.s I did read the 'how to mod your GTP' thingy but I'm unsure of how far I should take this..I'd like to see 13's but safely..

Get SSAC headers. $350 to your door sound good?

Yes I do think the SSAC headers seem like a better buy..I've looked into them and think I might go that rout. I just checked the website and it says nothing about hardware + how they remounted the heat shield.

I'm not worried about the header install but the rockers on the other hand kinda make me iffy..I don't know much about em but if its just a matter of swapping them out and torquing them to spec I'm game...That already sets me back about $600..another $100 for a tune, and about another $100 for some other odds and ends(tranny filter, plugs, t-stat, ect..)..add the pulley at the end and I'll be around $900 with the puller rental.

A bit more than I wanted, I was shooting for under $500..but the extra cost to keep it safe is well worth me NOT blowing the motor lol..

I understand the exhaust work part of it for sure!! And I think the headers sound like a MUCH better deal now..I don't mind doing the install at all. I did the full exhaust on my old fox body notch..it was a walk in the park..The pulley swap will be the last thing on my list besides the tune..I won't even order the stuff until everything else is on the car so I'm not temped lol..

I see you have a 04 but can you give me any other details about the rocker install?

I really do appreciate the advice, my next question would be about the headers throwing a cel until I have the tune done..will that matter besides the annoying light??

So I've been reading and doing a lot of thinking..I'm still about 1 month away before the car will be ready for even a 3.4-3.5" drop. I want to get all the little things done I listed in my first post done before I pull the trigger on a pulley..

I decided I'm ordering the headers and 1.9 rr first..Because I'm going cat-less and I'll have supporting mods to safely run a 3.4"..I think lol...but I was thinking..stepping down to a 3.3" pulley with the rockers will be the same as running a small cam, no?? I know that with the 3.25" a cam & the inter-cooler are must have items..but this is where I'm thinking you're going to tell me I'll have to scan the car to find out how much it's knocking with the 3.4 after the supporting mods..

What I'm getting at is every .1" drop is ~1psi right..If some guys can run the 3.4 knock free with headers and other supporting mods, than why cant you drop another .1" with the 1.9rr and a good tune?? Is it that much of a difference that it makes our cars knock like crazy, I never put anything less than 93 in the car now so I have decent gas..I used to be able to get 94...

Another things I've been pondering about is E85...I can get it right by my house for about $0.50 cheaper than 93..should I get larger injectors and tune the car for that?!?! with E85, 1.9rr, headers, and all supporting mods above that will the 3.3" be safe or just pointless..how about this set up on the 3.4"..should be much better and zero knock right?!?! I REALLY like the idea of paying $2.50 a gallon again lol..

Any E85 users on here??!

it ALL depends on the car. All of them are different so they all respond differently to boost.

It was my understanding that you needed a cam for a 3.35 and for a 3 and lower it was I/C.

Originally Posted by superv6

im impressed bro. it sounds like youve been doin ur research. i hope it works out for you. ive got the basic 3.4 pulley setup in my car, you know plugs, plog, dp etc. and my car ran a best of 14.1 at the track here in kc. this is also considering that my car felt like a flat 15 second car stock. so id say youde be in the 13's easy if you do all the right ****. good luck man.

Thanks man!! I would of thought your car would of trapped higher than 97mph with those mods? When I ran mine it was still heat soaked from the ride there. and it trapped 94mph. Although I did pull the front head light lol??!..

But anyway yeah I've had the car for a while and last season I wanted to mod it but I went ahead and did all the gaskets, maf, full breaks, ect. Now it's time to change the tranny fluid and filter and should be good to mod.

I know different cars will react differently to more boost but I just had it in my head that adding 1.9rr would be the same as a small aftermarket cam..with that being said I would think with good gas, all supporting mods for a 3.4, and a great tune, the 3.3" would be achievable knock free..

I guess I'll only know by doing all this stuff, then adding the 3.4", and scan it..If it has 0 knock maybe I'll step down to the 3.3 and re-scan..

The time I ran in the 1/4 normal for a stock GTP?? I think I could get an idea of if my car is knocking now if it was slower..