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rzibilske77
02-24-2005, 02:31 AM
i'm just wondering if i went to far by adding a 10% blower pulley instead of 5%.
My only mods are k&n panel filter, removed silencer, and very free flowing exhaust, no resinator, or cats.
With my exhaust being so wide open, I would have to really get on the throttle to get boost between 5-10 psi
Now that i put on this 10% pulley, my boost just went sky high :)
The Engine is in gr8 shape, as it has 90k, so am I in danger of blowing the head gaskets??
Thanks for any input...................Robert.....

CMac89
02-24-2005, 03:10 AM
i'm just wondering if i went to far by adding a 10% blower pulley instead of 5%.
My only mods are k&n panel filter, removed silencer, and very free flowing exhaust, no resinator, or cats.
With my exhaust being so wide open, I would have to really get on the throttle to get boost between 5-10 psi
Now that i put on this 10% pulley, my boost just went sky high :)
The Engine is in gr8 shape, as it has 90k, so am I in danger of blowing the head gaskets??
Thanks for any input...................Robert.....
If you have a '94/'95 you need to go down to a 5% and if its an 89-93 then dont worry about it. You will eventually blow the headgaskets, so theres really not much you can do about it with a 89-93 SC, unless it already has fel-pro head gaskets.

David Neibert
02-24-2005, 10:01 AM
Those head gaskets are going to blow no matter what you do. Since you opened the exhaust you should be able to run a 10% without a problem. Rule of thumb....anything over 14-15 pounds with a stock cam and heads is counter productive.

David

92silverlx
02-24-2005, 01:37 PM
don't mean to get off topic but I have a question David, I recently blew the gaskets on my car and decided to port the heads and go with a milder cam, I cleaned up the short turn radius on both the exhaust and intake side, port matched the intake side to the manifold, smoothed out all the casting bubbles, and I also ported the exhaust manifolds to 2 inches. I went with a mild cam here are the specs.

grind#~259HR-115

lift~ .480
intake exhaust
duration~ @ .050 204 216

Lobe seperation 115

I've noticed that I'm only making around 10-11lbs at WOT with the 5% the car feels like it has quite a bit more power, I have noticed that it has lost a little bit of its "umph" off the line though. Is this cam supposed to be used with higher boost?

David Neibert
02-24-2005, 02:29 PM
don't mean to get off topic but I have a question David, I recently blew the gaskets on my car and decided to port the heads and go with a milder cam, I cleaned up the short turn radius on both the exhaust and intake side, port matched the intake side to the manifold, smoothed out all the casting bubbles, and I also ported the exhaust manifolds to 2 inches. I went with a mild cam here are the specs.

grind#~259HR-115

lift~ .480
intake exhaust
duration~ @ .050 204 216

Lobe seperation 115

I've noticed that I'm only making around 10-11lbs at WOT with the 5% the car feels like it has quite a bit more power, I have noticed that it has lost a little bit of its "umph" off the line though. Is this cam supposed to be used with higher boost?

I don't know how much boost the cam will work best with, but if your only getting 11 pounds then your leaving some power onthe table. I would add a 5% overdriven jackshaft pulley to increase the boost a couple pounds.

Whenever I change something on the car that lowers the boost (exhaust, cam, ported heads, fmic...ect) I overdrive the blower a little more to get it back to around 17 or 18 pounds. If I do something that increases the boost, I just switch to a larger supercharger pulley to lower the boost.

I can't tell by your sig what kind of blower you using...but you might want to consider an MPII or S port with the MP inlet before overdriving it much more. Those will produce more boost and require less hp to spin than a stock blower.

My car gained 50 rwhp and 70 rwtq by switching from an early style ported blower and plenum, to the MP II case and MP plenum.

David

92silverlx
02-24-2005, 02:42 PM
thanx for the info david, I'm running an early style blower that I ported ....it gets the job done for now, looks like I'm gonna have to look for some MP stuff or Dave Dalke's AR.

Joe

ThunderDave
02-24-2005, 07:21 PM
Hey David, I've got a question about boost, but from a different angle. I had gutted cats, no resonator, flowmasters and a 5% od pulley. Yesterday I had magnaflow cats and resonator installed and in thinking the boost would go up a little because the exhaust would be a little more restrictive (but not that much if any), the boost went down some instead. Does this make sense? I have the 10% pulley to put on that I asked you about. Before the change, I had about 13.5 psi and now so far after the change, I think it's around 12-12.5 psi. I not worried about running the 10, just wondering why the boost came down some. Any ideas?

Thanks!

David Neibert
02-24-2005, 11:31 PM
Hey David, I've got a question about boost, but from a different angle. I had gutted cats, no resonator, flowmasters and a 5% od pulley. Yesterday I had magnaflow cats and resonator installed and in thinking the boost would go up a little because the exhaust would be a little more restrictive (but not that much if any), the boost went down some instead. Does this make sense? I have the 10% pulley to put on that I asked you about. Before the change, I had about 13.5 psi and now so far after the change, I think it's around 12-12.5 psi. I not worried about running the 10, just wondering why the boost came down some. Any ideas?

Thanks!

Don't know why it would go down, I would have expected to current system to be slightly more restrictive. Maybe gutting the cats actually caused some turbulance with the pipe getting larger and quickly going back smaller and that might have slowed the exhaust down.

Who knows...just put the smaller pulley on and enjoy.

David

ThunderDave
02-25-2005, 05:34 PM
Don't know why it would go down, I would have expected to current system to be slightly more restrictive. Maybe gutting the cats actually caused some turbulance with the pipe getting larger and quickly going back smaller and that might have slowed the exhaust down.

Who knows...just put the smaller pulley on and enjoy.

David

Maybe you are right about the gutted cats causing turbulance and maybe the magnaflow resonator flows better than the two pipes coming off the cats and Y-ing into one did. I'll get the pulley on tomorrow and report back.

Thanks!