Ok to run 10% OD pulley?

phils89sc

Registered User
My 89 SC runs very well, has a custom true-dual exhaust with a large Flowmaster muffler/resonator and no mufflers at the back. Headers are stock, piping size is 2.25 or 2.5", cannot remember (except at downtubes). The car only has 87K miles on it and is an auto. Could I safely run a 10% OD pulley? Is my exhaust open enough to allow this?
 
Kinda yes/no, you are going to over power the ability of your stock intercooler to cool the air charge and will actually slow you down in a 1/4 mile run.
 
it would offer a nit of an improvement, but from personal experience, i would just pony up and cash in on a double intercooler.

i ran a 10% on both my 94 and 95 sc's. 94 has 150k on the original gaskets, and i'm still testing the durability. just added an MP2 clone blower with stock overdrive, and plan on adding a double intercooler in the next couple weeks, and getting it tuned with quarterhorse to keep everything in check

on an otherwise stock motor, 10% will be fine, as i ran it for a long time, but be wary that its going to undoubtedly cause belt slip, so get a new belt, and you are going to gain some low end grunt, but your car will be pulling its full timing allowance on the top end, causing you to lose some power up there.

it certainly livens up your morning commute though... :D
 
My 89 SC runs very well, has a custom true-dual exhaust with a large Flowmaster muffler/resonator and no mufflers at the back. Headers are stock, piping size is 2.25 or 2.5", cannot remember (except at downtubes). The car only has 87K miles on it and is an auto. Could I safely run a 10% OD pulley? Is my exhaust open enough to allow this?

No, you will see minimal improvement in overall power with a un-ported early style blower.

I did see more power immediately off the line and it sure feels like a big improvement, but when I took it to the track my 1/4 times were the same with 5% and 10%. (same day same track) At the time I had a double intercooler with a fan.

IMO A un-ported early style blower makes so much heat that any improvements it may make down low in the RPMS it takes away in the high rpms when the EEC takes away timing due to high inlet temperatures.
 
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