Performance chip and pulley question

lattard

Registered User
I have a 1995, automatic SC. I am interested in the installation of a performance chip and changing the pulley. How do I find out what size pulley and which chip I need to do it properly so I dont have any issues later?

Any help would be appreciated
 
As far as the pulley is concerned. Buy an early style pulley. It works out to something like 3% OD. You don't want to go higher than that without doing something to the exhaust, and intercooler. Exhaust because it relieves pressure and allows it to flow better. (Downtubes, hi-flow cats at a minimum.)

As far as an intercooler, a good route is to go with a Double Intercooler, with a small puller fan attached to it to run constantly. This will/should stop the Air Temp.'s from climbing high enough to command the eec to pull timing.

If you get exhaust, and intercooler, you could possibly go as high as 10% if you wanted, although I wouldn't recommend it. Reason being, your car has the late model M90. Total OD with a 10% pulley is supposed to work out to 12-13%. That's too much for a double intercooler to handle.
 
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Also, if I may add. If you're going to go through the trouble of buying downtubes and hi-flow cats, just finish the whole exhaust. Don't let anyone tell you that you cannot fit true duals underneath the car. And if you get a full exhaust system made, make sure it has mandrel bends and not that crimped BS.

A rule about the exhaust on SC's is, they usually sound like complete crap without a resonator and mufflers.
 
Total OD with a 10% pulley is supposed to work out to 12-13%. That's too much for a double intercooler to handle.

That statement is untrue. I was running 10% OD on a late model blower, then 15% OD on an MPx all thru a double intercooler with a fan. There are plenty of people running 10%+ OD on a double intercooler with no problems. If built correctly they can be truely effective.
 
That statement is untrue. I was running 10% OD on a late model blower, then 15% OD on an MPx all thru a double intercooler with a fan. There are plenty of people running 10%+ OD on a double intercooler with no problems. If built correctly they can be truely effective.

I stand corrected. But, on a stock longblock, with at the moment, a stock exhaust and intercooler that isn't a very good idea.
 
On the 94/5 SC's running more than a stock 89 pulley will result in the knock sensor pulling all timing out and therefore no power increase. If you have a non-functional knock sensor then you can make more power but you will be flirting with detonation on a continual basis.

In the old days no one offered a chip for the 94/5's mainly because they did not understand why they would not respond to tuning changes. We now know why. The 94/5's have a better supercharger capable of more boost combined with higher compression, a different camshaft, and a more restrictive exhaust. These things combine to make the 94/5 SC non-responsive to pulley/chip changes. Even with an opened up exhaust and double IC we found that going from an 89 pulley to a 5% resulted in more torque at low rpm but no more power in the higher ranges due to the knock sensor pulling timing out very aggressively.

Upgrading the exhaust is a good place to start but don't go too far and make the car loud and obnoxious. This is one case where a little is good and a lot isn't any better.
 
I agree with Dave on the exhaust. With everything mine has done, the car isn't loud or obnoxious. I may be able to get a soundclip of it since I can't really drive it until the insurance adjuster comes to look at it.
 
On the 94/5 SC's running more than a stock 89 pulley will result in the knock sensor pulling all timing out and therefore no power increase. If you have a non-functional knock sensor then you can make more power but you will be flirting with detonation on a continual basis.

In the old days no one offered a chip for the 94/5's mainly because they did not understand why they would not respond to tuning changes. We now know why. The 94/5's have a better supercharger capable of more boost combined with higher compression, a different camshaft, and a more restrictive exhaust. These things combine to make the 94/5 SC non-responsive to pulley/chip changes. Even with an opened up exhaust and double IC we found that going from an 89 pulley to a 5% resulted in more torque at low rpm but no more power in the higher ranges due to the knock sensor pulling timing out very aggressively.

Upgrading the exhaust is a good place to start but don't go too far and make the car loud and obnoxious. This is one case where a little is good and a lot isn't any better.

David is referring to my car.It made 20 hp less with the 5% pulley vs the 89 pulley,although it made more low end torque with the 5%.The exhuast is free flowing and it has a D i/c with fan.
 
Also, going above 5% usually leads to the rotors shedding their coating which drops the efficiency of the blower at that point... at least mine did.

A chip can help out to keep the car running cooler by lowering the cooling fans on temperature so the motor will run cooler.... best matched up to a 180 tstat in this case. You can also gain a couple of ponies at the wheels by having the air/fuel mixture leaned out and a few other tweaks that will help out.

PM me if you want more info on a chip, or email me with the link below.

Fraser
 
It seems like the coating flaking off at high rpms isnt consistant. Ive been driving for awhile at 10% OD and I saw caseys blower with even more OD than me and his coating was fine also. Maybe yours were getting hotter because of the stock IC?

Corey
 
I dont know if you have inspection there or not, heres a clip of mine, no cats 3in mid section and borla's. Naturally the more power, the more noise. A stock sc with this setup might be a bit quiter. I think my setup is good enough for a decent ammout of power, a big improvement over stock thats for sure.

http://videos.streetfire.net/video/thunderbird-sc-exhaust_206655.htm

Corey

wow that sound pretty damn good! imo

whats all done to this exhaust! i picked up no cats 3in mid section and borlas

whats the spec
piping size
and all thanks
 
It seems like the coating flaking off at high rpms isnt consistant. Ive been driving for awhile at 10% OD and I saw caseys blower with even more OD than me and his coating was fine also. Maybe yours were getting hotter because of the stock IC?

Corey

Mine seemed good with no chipping or anything.. now this was a stock 94 blower rotors, not the GTP ones, but once I started OD'ing at 10% the coating ended up in my IC. You should have seen my face when Dave pulled the rotors out :eek:... not a month before the coating was there but now was totally and absolutly cleaned right off.

Fraser
 
wow that sound pretty damn good! imo

whats all done to this exhaust! i picked up no cats 3in mid section and borlas

whats the spec
piping size
and all thanks

Typically running without cats and a resonator leans to a very annoying sound inside the car, and sometimes its bad enough you can't hear the stereo.

Fraser
 
wow, I guess Im having good luck, I think theres over 150k on this late model Im using. The snout hasnt been touched either. I guess Im waiting for it to kill itself so I can put something nifty in its place :D

Corey
 
wow, I guess Im having good luck, I think theres over 150k on this late model Im using. The snout hasnt been touched either. I guess Im waiting for it to kill itself so I can put something nifty in its place :D

Corey

Could have something to do with not zip tying vacuum lines :D:p.
 
Do not run the cooling fan constantly w/o going with a heavy duty inline fuse bypassing the fuse box unless you want to have a melt down in your fuse box.
 
Frit Im getting tired of you letting out my race secrets like that. How am I supposed to get 1st at the shootout for 3years in a row if I cant keep my go fast tricks to myself.:p OK lets get this thread back on topic.

Corey
 
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