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99 GT Mods: Where to begin???

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Pandion28

New member
Hi All,
I have a stock 99 GP/GT and I want to change that. It's my daily driver, so I'm not wanting to do anything crazy, but I want tighter suspension with less roll & better feedback/response; and I want it to have snappier acceleration. I'm NOT a car guy, I know enough to have basic concepts down, but I've read so much that the details have me overwhelmed. And since I don't have any hands on experience doing this, I can't distinguish between hype or whether the subtle differences would matter in my case. So, here's what I have in mind as far as order of events goes: Please advise if you something out of order.
1) New cold air intake with a new PCM, at the same time I'm thinking new front & rear sway bars.
2) My end game would include a drop of 1" or so; nothing overly radical, just to improve the stance & improve handling a bit.
3) Cat back exhaust & bigger brakes.

Should I change any of that up, or am I missing something I should have included?
I've read a lot about different struts, sway bar sizes: diameter/hollow/solid, strut braces: both for & against, etc & my brain hurts!!!
Lastly, specific products. I have a great mechanic to handle any install work for me; but I kind of want to buy the parts & deliver them along with the car. I don't have the knowledge or inclination to buy things piecemeal, so I was thinking of buying everything from 3800performance.com, andysautos.com, or pfyc.com; but I'm sure there are other/better/cheaper places that I don't know about.

I know this is long, but I figure the more info you have now, the less you'll need to ask me. But feel free to ask. And thanks for the time to respond.
 


Start with the Cold Air Intake AKA HAI (Hot Air intake/Open Cone... that explanation is for another day) You can make one yourself for like 60$ bucks and build from there. Leave the new PCM/Tune for last and check out this thread

http://www.grandprixforums.net/safely-modding-your-3800-powered-car-17482.html#post204598

it will tell you everything you need to know also get to know the search function on youtube basically anything you want to do to your car someone has made a video to help give ya an idea of where to start!
 
None of that will do much.

Being a maf based system leaves you with some delay.

Engine doesnt make much power so after 60/70% tps, it will all feel the same.

Only thing you can do without sacrificing low end would be opening up your lim.

As far as handling, youd want sway bars in there too, lowering isnt good for handling. Throws the suspension geometry off.

Higher the spring rate, the less body roll you'll encounter.

But the ride will get worse as you go, even with quality struts.

Any higher than the spring rates you find with lowering springs and youd probably end up floating over irregularities in the road. Not good lol.

Stb's arent worth it to me, the chassis is still too loose even after both stb's have been installed.

For sway bars you might want to consider the gmpp kit as its the least expensive. After that you have the dorman front bar with an addco rear. They're both solid, larger than stock yet smaller and cheaper than slp bars from 3800 performance.

I have vogtland springs with bilstein hd struts. Great feedback from the road yet its not overbearing or unpleasant. Alao note that combo results in stock ride height.

Catback is 110% waste of time.

Wont sound pleasing nor will you net any power from it.
 
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Depends on how fast you want it. if you want real fast car, get a GTP. Or you don't really care that much then by all means stay with the gt. Just read the thread link above. Its just easier to make a GTP go faster than a gt obviously cause its boosted
 
DanPrixGTP said:
Depends on how fast you want it. if you want real fast car, get a GTP. Or you don't really care that much then by all means stay with the gt. Just read the thread link above. Its just easier to make a GTP go faster than a gt obviously cause its boosted
Click to expand...

Gtp's arent fast nor even quick haha.

easy go fast would be a z3 turbo kit.
 
Thanks Matt,
I've read a lot of your other posts prior to registering & posting mine. If I may, a couple of specific questions for you:
1. I'm going to take your advice on the SB kits; the rears give a choice in size, I believe it was 7/8 & 1 1/4. Suggestions?
2. You mentioned your combination of springs/struts yiled the same ride height, which is appealing as I don't really want to deal with the skewed geometry. I didn't
didn't see a Bilstein option on a website for my GP, and the Vogtland's were labeled as lowering springs. Do the struts offset a lowering spring or am I looking at the wrong thing? And, do you have a site you like for both those items.
3. Lastly, thoughts and recommendations on cold air intake. One of the other threads said it's easy to make your own but I don't have the inclination, or the ability. I'm willing to spend the money to buy something but I see so many different options & don't know the pros/cons of any of it.

Lastly, I don't know what MAF, TPS, or LMI are. I'm really the guy who enjoys sport driving, but knows nothing about the mechanics. I read a lot when I'm interested in something, but for me the details on this stuff just don't set in & I end up just getting overwhelmed.

Again, thanks for all the help.
 


Addco offers a 7/8ths solid or 1 1/4 hollow.

Given the lack of clearance I had and still have between my 7/8ths bar I wouldnt recommend any larger.

Since the larger one is hollow its probably a little lighter while being just as stiff. Also note its much more costly.

Go to allshocks.com , iirc thats one of the better prices for bilsteins in the states.

They incorrectly list comfort valving as hd and hd valving as sport though. You'd probably want comforts or "hd" as allshocks advertises them.

They raise the car a little so using springs that lower it slightly result in stock ride height.

Lim is the lower intake manifold.

Gm didnt seem to do a quality job when casting them. You could have a machine shop open it up to 1.9" by 0.88- 0.89".

Seems to provide a good increase all around without sacrificing power at all.

My comment about the maf was in regards to the method used to measure air going into the engine.

Most dont have any issues with these cars.

The tps is the throttle position sensor. My point there was after a certain point, pushing the pedal down further will have hardly and percievable difference in power.

For the intake id suggest one of the two zzp sells with an amsoil filter that cheapo aem filter on ebau right now.

Not a fan of oiled filters. Sacrificing filtration for power isnt a good idea for any engine.

An exhaust mod would be a good idea. Like a plog or down pipe.
 
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I like the HV3. If you can find a used one, id pick it up. I still thought it was worth the 200 when i had it, but eh. You could get a downpipe or some headers and get some more top end power and a little nicer sound.
 


Quick by 1997 standards...there are non boosted...smaller engined cars nowadays running faster times by a long shot.

Matt is right.

If you have a GT with a solid transmission; Z3 intercooled kit is the way to go...keep the boost around 6-10psi...somewhere in that range...all bolt on. All easy to do.

Bam, 300+ FWHP. In a few hours.
 
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