Thread: Why is my.. Top swapped car so damn slow?

Ok, I have been searching since yesterday for topics that would give me a general direction other than main. items to look into reguarding the slowness of this vehicle.

MY SITUATION
I traded my probe gt (yea you read that right) for this grand prix "gtp". I have since taken a deeper look into this vehicle and have figured out that it isnt a real gtp. Someone has either performed a top swap on this car, or has swapped the whole motor. I dont think it matters at this point. The car runs great. No problems, hesitations, smoke, missfiring, or anything like that. Other than how slow this thing is, it seems to be an awesome car. I just got back from a few hour trip and the car gave me no issues. Other than getting beat by a newish jeep rubicon.. (embarrassing to say the least). Anywho... I was told the car has the following mods, keep in mind the previous owner swears he thought it was a gtp

-180 thermostat
-zzp 1.0 tune
-1.9 rocker arms
-crow push rods
-dynomax exhaust
-CAI

Perhaps some other things that I am forgetting to list. Once I got back into town I stopped at a gas station and removed the supercharger belt. I was told to do so by another member in my other noob thread. I thought I would have the control to keep my foot off the gas but after the jeep situation I obviously dont. Anywho.. I got to the gas station and while I was filling up ( I swear cruise ships get better gas mialage) I removed the sc belt, untill I get a set of headers and a scan gauge. The thing that made me think, when I was on my way home I gave it a 2 gear pull and I didnt notice much of a difference in the performance of the vehicle, which is odd. I would think that the motor trying to pull air past a non functioning supercharger would hinder performance greatly.

THINGS I AM GOING TO LOOK AT TOMORROW
-first I thought there could just be a gutted sc on my car. Maybe for some reason a previous owner took the rotors out. But when the car is first started the pulley turns (keep in mind the belt is removed) and when you give it a little rev it spins. Makes me think the rotors are still in the sc

-Perhaps a boost leak of some sort? there isnt a boost gauge in the car at all so I supose this is a possibility.

- I will look over the vacuum lines and see if I can find something that looks off, even though I dont have a ton of experiance with these cars.

-Or, maybe the car isnt really that slow. All I know is my probe would have spanked this thing. Ive owned one other gtp and from my understanding a top swapped car should be a tad quicker than a stock gtp, but mine has some bolt ons, and my other gtp would have owned this thing.

Sorry for the long post but I dont want to be one of those noobs that makes a crap load of threads without searching, and thats how I feel. I am not retarded when it comes to cars. Just need some direction. Thanks a ton for anyone that can help.

8th digit in the vin is a K, let me know the car wasnt a gtp. But if read a top swap should be 5% quicker than a gtp, which this is not. I dont believe it is a problem with the motor at all. Its like... the supercharger isnt even there.

Originally Posted by KeithGTP03

If it were N/A it should still beat a probe. What's your boost/ kr/afr's/ltft's reading at?

Doesnt have a boost gauge, a scan gauge, and I dont know what ltft is. So im kinda in the dark with this right now. I can get a boost gauge and get it hooked up but I dont wanna push my luck with no scan gauge. But while I was searching around I happen to stumble on the thread that tells you how to top swap you car and at one point they said how to hook up the boost bypass valve. Top nipple goes to the supercharger tree (which im assuming is the three vacuum port thing on top of the sc itself. And that the bottom should be vented to the atmosphere. When I look at mine assuming I am looking at the right thing, the top goes to that tree looking thing and the bottom one goes to an electric solenoid of some sort and from there it goes back into the supercharger. Should I switch this? Or should I wait till I get the proper gauges to go messing with things?

You need to take pictures of your motor first and post them on here.

Second- You need to buy a scanning tool or find someone who can scan your car right now.

Third- Stay off the gas until you know more.

Too small a pulley and no headers?

The pulley is stock sized. Im gonna get an aeroforce before I look into anything further. But im leaning towards not getting any boost. Maybe the lines for the boost bypass valve arent hooked up correctly.

Originally Posted by Explicit_Spade

-zzp 1.0 tune I think I found the problem.

Thats BS, I have a zzp 1.0 tune and have had NO issues whats-so-ever.

Originally Posted by matt5112

Too small a pulley and no headers?

^^^ This.

THANK YOU, I DO NOT HAVE A SCAN GAUGE. I will be ordering one soon, and untill then the supercharger belt is off. I will look into local tuners.

-Can the ecu that is in my car be tuned?
-If it cant, what should I be looking at as far as another ecu?

Where do you guys get your aeroforce gauges from? I found one on ebay for $200 and areoforce's site is like $250 I planned on spending around $200 for one. Just wanted to make sure there wasnt a better place to be looking.

I am going to search for some answers, I wanted to start slow with the modding process but it appears I got thrown into the **** pretty quick. Aside from no one on here being able to read you guys have been pretty awesome.