Originally Posted by PontiacDad
I belive Dbtk2 has that very year and model, you should shoot him a pm?
My understanding is the car is somewhat rare and is considered special.....but talk to Shawn first.
The 4-door "TSTE'*" are much rarer than the 2-door "TGP'*" (which were converted SE models). The '90 - '93 Grand Prix STE'* are somewhat rare to begin with. Only 1,000 of the STEs got the turbo package, and only in '90. The only ways to tell them apart from their n/a counterparts are the badges, and the massive hood louvers (same kind used on the 2-door TGPs, and optional on '91 - '93 2-door GPs). They only came in maroon or white, and while I've seen tan interiors in STE'* before, I have yet to see anything other than gray on the turbo versions. The wheels are the same STE specific design, but all turbos were key-colored. Almost all the killer features are standard. The only options are CD player, leather and a power sunroof.
: The turbo version GPs produced 205 hp/ 225 tq from the factory. They were tuned extremely conservatively (see "Stock chip" section under common problems for reasons why). The Garrett T-25 turbo used were way too small for a 3.1L V6. The excuse by Pontiac was to limit turbo lag, but I suspect the real reason was to stop the potential of a V6 family car beating out the 'Vette and the likes. The prototype used a bigger turbo (unknown which) with some other variations, and produced 305 hp with a 1/4 mile time of 14 seconds flat. The magazines from the era had the production 2-door TGPs running anywhere from 15.3 - 16.3. Most of them run low to mid 15'* stock even today, 17 years of wear and tear later, so I don't know how accurate those magazine figures are.
: The easiest mod to do is get a chip. This will cure drive-ability problems, as well as dramatically increase performance. The Jeff M "Top Gun 160" chip kicks the fan on at 160°, requires a 160° thermostat, and pushes the hp up to ~240. Most TGPs run ~mid 14'* with this chip. Kenney'* chip (TGPilot on the boards) is supposed to go well beyond even that in power. Beyond that, several people have gone with bigger turbos, bigger injectors, rising rate fuel pressure regulators, 3x00 top end, etc. A member in Canada is shooting for low 12'*/high 11'* with his latest set-up. There is a lot of potential for these cars if you're willing to spend the money on a bigger turbo.
: Perhaps the biggest plague of these car. If it'* the original one, it'* almost guaranteed to be cracked, most commonly in the flex bellows on account of the poor quality materials used. Replacements are over $1k from GM, and are the same, poor quality, worthless garbage. Jeff M and TGPilot from the w-body and TGPForums sites make MUCH better/more reliable x-pipes for MUCH less. This would definitely be the way to go.
: McLaren was given 2 weeks to "perfect" the chip for these cars, and it shows. Normal running/drive-ability is an issue, let alone performance. The chip was programmed extremely conservatively, most likely to be on the safe said and avoid any tranny issues since they didn't have a chance to thoroughly test it. Again, Jeff M and TGPilot make terrific chips for these cars, with TGPilot'* chipping pushing the performance even beyond Jeff M'* top chip. Both will also cure your drive-ability problems.
Powermaster III ABS
: Not so affectionately referred to as "Walletmaster III", this is the most expensive common problem on these cars (or any car of that era that got ABS). They work decent at best when they're functioning, but most often are not. Luckily, a new ABS accumulator (the brakes are hydraulic like the first SSE'*, not vacuum) takes care of any charging/stopping issues a good portion of the time. You can get one for around $200 from GM, or $100 from Prior Remanufacturing. Should you need the whole unit, be prepared to plop down over $2k at the dealer for a rebuilt one. Otherwise, you have a couple other options. Prior Remanufacturing rebuilds them for ~$800, with some improvements to minimize future failure, or you can convert them to non ABS (cheapest, and most reliable option).
Any other questions?