Pulley effects on power?

T-bird Tim

Registered User
If I used every available pulley upgrade for my SC; any idea of how much more power that would be? 10% for the MP2 blower and underdriving all the accessories and using the MP jackshaft pulley. Seems like it would wake it up pretty well. Your thoughts?
 
Wow, 41 views and no one has any input on this? I was hoping there would be some folks on here that had experience with this and could give me some insight.
 
for me

i have a 5% JS and unederdrive + ported exhaust and borla res and it dont make much diffference for me the best thing to do before upgrading blower pulley is to get a double IC or at least a fan and a good exhaust upgrade too!!!
 
Sorry. I guess I should have stated what I have on the car already. MP CAI, 75mm T-body, 76mm MAFS, S-port with MP plenum, raised top, double IC with fan, 38 lb injectors, long tube headers with SCP exhaust. Chipped and custom tune. All current pulleys are stock.
 
I'm not sure about how much power increase you'll have but when I put my accessory underdrive pulley set on I was .1 second quicker in the 1/4mi. The 5% sc pulley would probably be another .1 sec quicker than the stock pulley.
 
At dyno 2 years ago.
Mild cam, ported heads, DIC, exhaust and s-port. Stock TB and plenum. '94 Automatic.

5% OD - 282 rwhp, torque 360
10% OD - 287 rwhp, torque 367 mostly low end gain, probably some belt slip.

Couldn't run 10% before porting and cam due to detonation. 5% was marginal, maybe less than than marginal, considering the hg job soon followed by spun rod bearing and expensive rebuild.
 
call up victor with spinningwheels-sc and get his 7% power pully.. u will get the best bang for ur buck..

if u go throw him tell him ironworker sent u there and he will know
 
If I used every available pulley upgrade for my SC; any idea of how much more power that would be? 10% for the MP2 blower and underdriving all the accessories and using the MP jackshaft pulley. Seems like it would wake it up pretty well. Your thoughts?

20% OD and 38lb injectors? Boom.
 
First you call it a MPII, then you call it a s-port, and now you are calling it a MPII. Which one is it?

Would the MP2 blower hold up to that much boost?

The blower will hold up to that much boost. It may not hold up to that much overdrive/rpms. That would depend on the how good of rotors are in it.
 
It is an s-port, To me basically the same as an MP2. Doesnt compare to the Stegmeier ported one I had on my 35th. Since we are splitting hairs should I change the post to ask if either of these types would hold the boost? And of course due to the number of SCs I have owned each with different levels of upgrades; I may at times get confused as to what is on this one versus the one I had before it. Anyone that has owned a few could probably attest to this.
 
Last edited:
It is an s-port, To me basically the same as an MP2. Doesnt compare to the Stegmeier ported one I had on my 35th. Since we are splitting hairs should I change the post to ask if either of these types would hold the boost?

If we really want to split hairs is it a true s-port?

An S-port is a 94/95 blower that was ported by Magnason (an Eaton Distributor). There are a lot of members here that think if they have a ported 94-95 it is a S-port, that is not the case.

A MPII is a 89-93 blower case with the outlet ported and had the back cut off and a new back glued on to resemble a 94/95 inlet.
 
When I bought the car from the previous owner I was told is was an s-port. I later found the receipt from magnuson while going through them after I purchased the car. It's amazing to me how much money can be dumped into these cars and you get next to nothing when you sell them. I added all the receipts together and it topped out over 20k but I bought the car for 3k. Great deal for me but I have been on the other side though.
 
So 60lb injectors first, Should be ok then right? Would the MP2 blower hold up to that much boost?

It's not the blower you have to worry about, it's the air fuel ratio, intake charge temp, coolant temp and timing (aka the Tune) that you need to be concerned with at 20% OD.

I was overdriving my MPII about 23% with a 10 rib ESM pulley system for several years but was only getting around 17 or 18 pounds of boost with ported heads, oversized valves and a somewhat agressive cam. Belt slip becomes a big problem when trying to spin the blower much more than 15% OD.

Overdriving from the crank pulley or the jackshaft pulley will improve the belt slip situation because of the larger surface area. If you want to use underdrive pulleys, you can't use the MP 10% crank pulley and will have to overdrive the blower using the jackshaft and blower pulley, and this will require the use of upgraded tensioner springs.

Increasing the injectors will only help if you have enough pump to support them..suggest switching to a 255 lph high pressure Walbro.


David
 
If it's from Magnuson, then it's an S-port. The Sport is no good past 15% OD as it will generate too much low rpm boost and too much heat. On an internally stock motor any more than 10% OD with that blower is a recipe for trouble, especially in the Texas heat.

At 10% OD the 38's will be ok.

Suggest you forget about overdriving the blower and get heads and cam first.
 
Back
Top