5% SCP overdrive on 94-95 supercharger

spada

Registered User
SCP doesn't really specify, but does the 5% aluminum overdrive pulley that they sell mean 5% overdrive for the early style blowers?
I searched for a thread on this, and I saw a post with diameter measurements. If their measurements were right, the SCP 5% overdrive pulley is more like 11% overdrive on my 1995. Which would explain why I peg the stock boost gauge now. I installed a double intercooler at the same time, so maybe I gained a slight amount of boost from that too (less pressure loss)
 
So if wanted a true 5% overdrive, i should have went with a 5% jackshaft pulley, and left my supercharger pulley stock.

ok, just wanted confirmation...thread can be closed now, lol.
 
the thread i found ( http://www.sccoa.com/forums/showthread.php?t=21145&highlight=pully+calculations ) shows this:
SC pulleys:

94-95 3.275"
89-93 3.135"
5%OD 2.935"
10%OD 2.850"

So the early style blower pulleys are more like 4.5% overdrive, and the 5% overdrive is 11.5% overdrive on the late model blowers, and 10% is 15%

so.......anyone have a 89-93 pulley they want to sell?
Or, Charlie, are you ready to sell that 94 Pearl white Auto SC back to me??? haha
 
max boost before the changes was around 12-13psi. just 73mm maf and 70mm throttle body as mods...

then i installed the SCP 5% pulley and ken wagner double intercooler. max boost is now past 15psi...

i need to get rid of the stock y-pipe immediately!!!! it's winter, so i won't be driving the car, so i have plenty of time.
 
What pressure are you aiming for? 14psi?

If I were you, I'd stick with the stock setup until there are no other worries. Why push the perceived limits now, if you plan on upgrading the exhaust later anyway? :) I would estimate that the difference in power between the stock late model and stock early model pulley on your setup would be around 5rwhp - probably not worth the risk, if you think it's there.

Save the 5% and just wait until you have the car (exhaust, etc.) where you'd feel comfortable with the 5%OD. :D
 
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point taken...yeah, i'll be leaving the 5% (11%) overdrive on the car. I don't expect it to cause any problems.
 
What pressure are you aiming for? 14psi?

If I were you, I'd stick with the stock setup until there are no other worries. Why push the perceived limits now, if you plan on upgrading the exhaust later anyway? :) I would estimate that the difference in power between the stock late model and stock early model pulley on your setup would be around 5rwhp - probably not worth the risk, if you think it's there.

Save the 5% and just wait until you have the car (exhaust, etc.) where you'd feel comfortable with the 5%OD. :D

well that ended up being real good advice. last night making some spirited runs, the cooler air was too much for my injectors I think, I had some bucking in 2nd and 3rd gear.
I swapped the stock pulley back on today and went for a test run. I still pull between 14 and 15 psi, thanks to the intake mods and double intercooler, so I figure the 11% overdrive it's too much at this time without a tune. everything is back to running smoothly at WOT
 
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