98 GP Engine Overhaul

[agaylord]

Hello all, I've got a plan for my 98 Grand Prix GT and I was hoping for some criticism, advice, etc. I recently had the upper plenum go out and had 600 dollars worth of work to replace the intake and get my car running again, which lead me to start thinking of a more long-term solution to keeping my car alive. Here's what I want to do (this 3800 series II engine has 157k miles on it, the tranny has been rebuilt and has close to 70k):
Hone the cylinders
New pistons, rings
Clean cylinder heads
Add supercharger w/ smaller pulley (diy rebuild?)
Cold air intake
Possibly a cat-back exhaust system
I want to do this work because I feel its cheaper than buying a different car, plus I know that its going to last a long time, and it'll boost my power which never hurts. (oh and i love the leather and the automatic-everything, i don't want to lose those). So...how does this sound? Do I need to do any computer mods? Any other advice/tips?? I greatly appreciate any help you can give me. Thanks!!

[richtazz]

There are many discussions on the forum about supercharging the base GT. It will require a lot more work and parts than most imagine, and isn't worth the expense and trouble. The 4T65-E transaxle isn't made to handle the torque of the supercharged engine, so a 4T65E-HD from a GTP (or an aftermarket performance trans) would be highly advisable.

[agaylord]

okay thanks good to know, how about the rest of the mods?

[OJ_]

Originally Posted by agaylord

how about the rest of the mods?

I had just answered a question like this but it was on a GTP. However some of the modding advice I gave applies here as well. I will cut and paste a small section that you can use since the rest of it is on GTPs.


1.) Open the intake, get a nice Cold Air Intake. K&N make good CAI's but they are pretty expensive. Make sure you shop around and read forums.
2.) Open the exhaust, at least remove the ubend and get a nice magnaflow cat. Doing a 3in downpipe with ubend delete and magnaflow cat is a good start to the exhaust.
3.) Get a performance PCM to replace your stock PCM. A performance PCM is tuned to tap into your car's unused potential.

There are a couple of sites you can use:
http://www.zzperformance.com
http://www.3800performance.com/


I suggest shopping around and getting to know the sites before you choose who to use. Just looking at different items and reading about them will teach you the basics you need to make informed decisions. Always ask questions before you move ahead with an upgrade.

There are a few other things you can do, but you are kind of limited. If you are looking to supercharge you are better off buying a GTP. It will cost you alot of money in parts and labor getting your engine up to spec before you can safely run a supercharger. The money spent in that respect is better spent on an actual GTP.

Please dont take my criticism as negative, but I think you should reconsider the planned upgrades on your current car. The money you would save if you chose not to upgrade your GT + money made by selling it would put you pretty dang close to buying a decent GTP, that is my


Good luck.

[duffman87]

what do you think about of putting a GTX grand prix V8 motor in a 2002 grand prix gtp. I know it will cost alot but is it possible. and if it is about how much and how much work. i want to scare those teenage mustangs when i pull up next to them. i know the new 2007 or 2008 gtx have 305 horse with there V8 so i want to know if it would fit

[richtazz]

There are soooooo many obstacles to swapping in the v-8 that you need to forget that pipe dream. A properly modded GTP can whup a mustang, Right Bnaylor?

Remember, the GTP supercharged engine isn't just a Series-II 3800 with a blower bolted on. It has better flowing cylinder heads, different pistons, etc... that will still outperform a GT block/heads with a supercharger mounted. Another alternative is an aftermarket turbo for the GT engine. One forum member had a video clip of one runnng a 9.83 1/4 mile and stomping a Dodge Viper in the process, all still running through the front wheels. The performance potential is there for the GT, but it costs. The GTP's are so much easier and cheaper for the average Joe to mod up.

[duffman87]

what should i do to beable to get the GTP to at least 11 secs 1/4 mile and a great 0-60 speed that would waste a mustang and camaro