I'm Stumped Here

455Poncho

455Poncho

Registered User
I raced a buddy's modded GTP the other day. Lost by 3 car lengths up to 95 mph. I added a 10% pulley, and took the back half of the exhaust off past the resonator, and i tied a car that he tied. Car felt fast and strong. Last night and today i changed the gears to 3.55's, raced him again and lost by the same 3 car lengths again. He hasnt changed anything. How can my car run the same with gears, pulley and less exhaust as it does stock?!?!? It has only seemed to have gotten slower since the gears, but they are installed properly. I have no idea wtf is going on. What could cause the car to be down on power?!?!?! The only problem is a leak in the thermostat housing, since i installed a 180 when i did the pulley. Frick, i couldnt even pull from a stock prelude today at speed. Something is definantly wrong :mad: :(
 
Maybe you should stick to the Grand Prix. an just keep showing the SC. was that your SC in the Three Hills show?? if it was i have a pic i can send ya of it.
 
devlin said:
Maybe you should stick to the Grand Prix. an just keep showing the SC. was that your SC in the Three Hills show?? if it was i have a pic i can send ya of it.
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Wasnt mine. I couldnt make it to 3 hills because of work. My SC isnt nice enouhg to show unfortunantly. Although I might think differently ;)

This is making me crazy. I mean who's car goes the same speed after pulley, freer flowing exhaust, and gears. Makes no sense, something else must be wrong
 
Based on info from some other threads around here I'd be pointing fingers at that 10% pulley. The idea I get is that without other fuel and computer mods, like a Tweecer or something, they make the car slower. This is just from reading threads, I haven't done any real research so it may be wrong.
 
Parker Dean said:
Based on info from some other threads around here I'd be pointing fingers at that 10% pulley. The idea I get is that without other fuel and computer mods, like a Tweecer or something, they make the car slower. This is just from reading threads, I haven't done any real research so it may be wrong.
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Definantly something to consider. Im gonna get it in to get tuned by a local guy here soon. The problem i have, is that it ran strong before the gears with the 10%, but now after the gears, it about as good as stock.

Im banging my head against the wall here. mother ford :mad:
 
It seems that you 'Bird is stock except for the 10%, the back half job on the exhaust, and gears.

I do know it's said that the 10% isn't to good with ANY of the stock exhaust still in place but another thought vcomes to mind too. At what RPM are you shifting? I understand that stockers don't get to much acceleration done after about 4300rpm so shifting higher than that hurts ET's. Perhaps you were shifting higher than usual with the new gears? Just a thought.
 
If you have a 10% and only took off the exhaust after the res, that will not be good enough. There is pretty much no change at all unless you take it off in front of the res. And if you have a 5-speed the 3:55's do not run very well. My car always felt slower with the 3:55's. It keeps the car in high rpms too much and makes you have to shift to often and makes first gear useless. Go to a 3:08 or 3:27's and I am sure you would close the gap some. Then ditch the factory downtubes and resonator.
 
I would clock your car 0-60 a few times to get a baseline,reinstall your stock pulley,reclock your times at the same spot, and see if your 10% pulley is the problem.You cant go by seat of the pants because the quicker boost spool up with the smaller pulley will make the cars part throttle response better.You havent dealt with the main source of backpressure with your stock exhaust which is the resonator forward.When I added a 5% pulley to my 95sc auto with the stock exhaust the car felt noticeably stronger at part throttle but ran .4sec slower consistently 0-60.With all the traffic in cowtown ,finding a place to run 0-60 will probably present some challenges. Good luck.
 
kws6000 said:
I would clock your car 0-60 a few times to get a baseline,reinstall your stock pulley,reclock your times at the same spot, and see if your 10% pulley is the problem.You cant go by seat of the pants because the quicker boost spool up with the smaller pulley will make the cars part throttle response better.You havent dealt with the main source of backpressure with your stock exhaust which is the resonator forward.When I added a 5% pulley to my 95sc auto with the stock exhaust the car felt noticeably stronger at part throttle but ran .4sec slower consistently 0-60.With all the traffic in cowtown ,finding a place to run 0-60 will probably present some challenges. Good luck.
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A fellow calgarian?? I've gotta meet with some of you guys :D
 
more food for you...

I love to just beat the guy I am playing with, that way you can always get him again and most of the time for more $$$. Nothing will kill you more than what you are tring to work out right now.. Are you sure your buddy is not playing with you and your mind??? Get some real times then go looking for your answers. Just the thoughts of one of those street racers that loves to play the crowd for ALL the $$$ when you can..... Good luck.....Rich
 
Re: more food for you...

pro street rich said:
I love to just beat the guy I am playing with, that way you can always get him again and most of the time for more $$$. Nothing will kill you more than what you are tring to work out right now.. Are you sure your buddy is not playing with you and your mind??? Get some real times then go looking for your answers. Just the thoughts of one of those street racers that loves to play the crowd for ALL the $$$ when you can..... Good luck.....Rich
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Definantly not one of those guys. His car ran 14.7.

The problem is that i lost the exact same to him stock as i did with gears, pulley, and less exhaust.

Obvious improper shifting, heat soak, and not that much help from the exhaust all contribute, but im still mistified as to how the car can be faster with 2.73's than with 3.55's
 
10% + stock resonator = bad for backpressure, power, and especially headgaskets!

The resonator is said to go down to a 1 inch opening, and is the main source of backpressure in the factory exhaust. Replacing or removing it should definatley produce a difference. I believe the next most significant source of backpressure after that is the factory cats, with their 90 degree bend after the manifolds. Upgrading these to high flow will also improve things.

Otherwise, definatley remove that pulley!
 
Too much shifting, RPMs stay way to high keeping the car out of its powerband. Sure 3:55's might work well in a mustang but not in the SC. I had them for a month or two until I changed them out. I went to 3:08's and they were much much better. 3:27's might have been better but I do to much highway driving. But even if the car was a 1/4 mile car only, I would still not reccomend 3:55's in a 5-speed SC. Way to much shifting for way to little movement.
 
i think these cars have peak horse between 2 an 3 grand
i hardly ever shift above 3500 i like the 2.73 these cars are made for it unless racing i would try 308 or 343 gears and skip first i was thinking if i ever raced i would try skipping 1st with the 273 gears lol with 355 you could prob skip 2nd
 
Yes you can start in third. When I had the 3:55's i started in 2nd most of the time unless I was on a big hill. And when I had the 3:55's launching in second still produced a ton of wheel spin. They are just too steep for the 5-speed. They have no real use unless you have a built motor that is able to run up to 6500-7000 RPM's.
 
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