Adding Horsepower!!!

Hello there;

To start off I have a 98 grand prix GTP with 98k miles on it. I have three questions a) What are some of the best ways to keep my car running well I do not want my transmission to break down tomorrow
b) How many miles do you think I have left until my car is done with, I do all the normal matiences to make sure the car is running well. Since I have a few miles on my car I do not know if it would be a good idea to add some horsepower to it if so c) What can I do to add about 50-60 horsepower
Also, what is the stock horsepower on a 98 grand prix gtp....

Thank You for all your replies

a) Do supercharger oil replacement annually. Service tranny with ATF replenishment and screen filter - every 50K miles or less. Unless already done, changeout struts. It will help keep rest of steering and suspension system from wearing out prematurely.

b) 98K miles is nothing. I have a '97.5 GTP with 91K miles and drag race every season. I see no problems with modding with the mileage you have. I run low 13s @ 104 mph with my mods.

c) Stock hp is 240 and 280 ft-lbs torque. A 3.4 - 3.25" SC pulley, CAI/FWI and re-programmed PCM is a good way to pickup 50 hp.

The horsepower rating is in the 240range stock. If you want to add horsepower to the car there are some fairly inexpensive ways to do that. If you want to keep the stock exhaust then you can just have the ubend deleted. This is the funky u-shaped piece on the back side of the resonator, it restricts exhaust flow and decreases horsepower. If you want to do more to the exhaust you can spend about $800 and install a set of headers, good for about 20 to 30 extra horsepower when connected to a freeflowing exhaust. A reprogrammed PCM is a good investment for more power too.

If you want get some additional horsepower install a smaller pulley on the supercharger. A 3.4 or 3.25 inch pulley will increase power and not cause any drivability issues. You should also install a cold air intake system for more air flow into the engine. With these mods alone you should be able to get the majority of the horsepower you want.

As for your transmission they are a wild card in these vehicles. The one in my GTP lasted to 138K before it went totally out and had to be rebuilt and it was hot rodded a lot. Changing the fluid and filter regularly will help keep it in good operating order but remember nothing lasts forever.

As far as longevity goes these engines with proper maintenance can go 250K miles with no problems. One thing you may want to do as far as maintenance is to change the coupler in the supercharger as the stock ones fail after many miles but GM does not sell one. Go to ZZperformance for one. Also change the supercharger oil regularly which will keep it operating well over the years. Finally, use synthetic oil in the engine. This will lubricate much better and help the engine last longer. It really doesn't matter if you have used only dino oil over the years. I hope this answers your questions.

How do I go about chaning the pulley to a smaller one and also how do I change the supercharger coupler?

Any tutorials....

Also, was looking at thermostats at zzperformance I want to get a 160 but it says something about PCM commands to rich of fuel. Should I just stick with a 180?

How do I go about chaning the pulley to a smaller one and also how do I change the supercharger coupler?

Any tutorials....

Here is the procedure to remove the snout and replace the coupler:

http://www3.sympatico.ca/aepa/blowerinstall.html


Here is the procedure for a pulley swapout:

http://www.pulleyboys.com/swap.html

I recommend getting a modular pulley system that way you can swapout pulleys without a puller later on.

I would not go to a 160 degree thermostat unless you get a DHP or Intense PCM. They have programming to compensate for the lower temp. thermostat. Also, the fan turn on points are altered to turn on cooling fans at 185 degrees. A 180 will probably work fine in the interim.

Good luck!

Am I able to rent a pulley swap out, and if so where am I able to rent one from? I just want to change the pulley out this one time and later on actually purchase one for keeps.

Am I able to rent a pulley swap out, and if so where am I able to rent one from? I just want to change the pulley out this one time and later on actually purchase one for keeps.

You can check with places like Autozone or Advanced but I doubt they rent the SC pulley tool. I had to purchase mine a few years ago. I found out later that a local speed and custom shop rented them. But since then I installed a modular pulley system and the puller is no longer needed.

I recall one GTP owner on the forum had a auto mechanic cut his off so he could install his undersize pulley but I wouldn't recommend this route if you plan on keeping the old 3.8 pulley. Good luck!

Went to grandprixstore.com and saw a pulley they sell and was thinking about getting the 3.4. Now I haven't made any modifications to my airfilter at all. But, was thinking about purchasing a k&n filter cone and then installing and remove the box all together. Would that be the smart thing to do or do you recommended something else?

Went to grandprixstore.com and saw a pulley they sell and was thinking about getting the 3.4. Now I haven't made any modifications to my airfilter at all. But, was thinking about purchasing a k&n filter cone and then installing and remove the box all together. Would that be the smart thing to do or do you recommended something else?

The 3.4 is a good all around pulley. On air intake mods, I've got a Thrasher CAI but there are several options for intake mods. It depends on your budget. Which intake kit were you looking at? Just about all kits will require removal of the stock airbox. With the airbox removed you'll have to make a provision for mounting/securing the PCM module. Intake mods are beneficial when you install an undersize pulley and will help reduce knock retard (KR).

BTW:
I forgot to mention the coolant reservoir is mounted on the driver's side of the engine on 97 - 98 models so it may be in the way of your intake mod. To correct this you'll need a coolant reservoir from a '99 and up model. It mounts on the passenger side strut tower.

How do I go about adding more torque to my vechile? I want to add about 40 lbs more.

The pulley will add plenty of torque. With just a 3.4 pulley/intake my car pulled over 300 ftlbs of torque at the wheels.

How about changeing out the PCU? On my GTX that was the first thing I chaged, the went to the 3.4 pulley, then the cold air box. That was the first weekend.
As long as you change the oil and trans fuild, I don't see why you wouldn't get allot more miles out of your car.

Update:

Well, I just went ahead and purchased a 3"4 pulley and puller, 180' thermostate, gatorback belt, supercharger oil, and upgraded to 8mm spark plugs and a new fuel fitler so hopefully I won't have a bad knock.

The PCU will bring everything together. Maybe it's just because it made one of the biggest differances.
Well read up on them. I think you will agree. Good luck.


http://img.photobucket.com/albums/v425/kustomkid54/evil.gif

Update:

Well, I just went ahead and purchased a 3"4 pulley and puller, 180' thermostate, gatorback belt, supercharger oil, and upgraded to 8mm spark plugs and a new fuel fitler so hopefully I won't have a bad knock.

Well I recieved my pulley and my supercharger pulley puller from zzperformance. Now I seem to have a problem I can't seem to get the large bolt into the center shaft... Do I need to hammer it lightly to get it all the way in? Next concern I didn't purchase the anti-seize lubricant and one of the steps says that you need to apply this lubricant and not to skip this step... Can I purchase some lubricant at like autozone? Also does anyone have a link online on how to disassemble the pulley using the puller that I purchased from zzperformance?

Well I recieved my pulley and my supercharger pulley puller from zzperformance. Now I seem to have a problem I can't seem to get the large bolt into the center shaft... Do I need to hammer it lightly to get it all the way in? Next concern I didn't purchase the anti-seize lubricant and one of the steps says that you need to apply this lubricant and not to skip this step... Can I purchase some lubricant at like autozone? Also does anyone have a link online on how to disassemble the pulley using the puller that I purchased from zzperformance?

Oh, the ZZP puller? Yeah, a lot of people have problems with it and their instructions. Can't help you there. I would not take a hammer to it. I have a Pulley Boys and it works great to include re-installing the pulley. I only have instructions for the Pulley Boys puller.

The anti-seize compound is a must. It is available at all automotive stores. Use a lot of it on the sleeve, bolt and shaft.

Problem now........
Put the whole pulley together and now I have a problem hooking everything up. The 15mm socket that helps to remove the supercharger belt is now in my way because, of the studs sticking out of the screw makes it impossible to completely rest the tool against the stock pulley so now i have a big gap so inserting the screws with that gap doesn't look right at all. Do I need to remove the 15mm socket on the stock pulley before continuing or do I have to remove something else in order for the stud to rest against the pulley?

Thank you in advance for your help