Calling on the experts, What is my Next Mod?

rickbtbird

Registered User
A question for the experts here....
I have a 1990 SC mostly stock except for exhaust.
I've done the modifications on my exhaust system.
  • Ported and coated Manifolds
  • High Flow Cats with down tubs
  • Magnaflow Resinator
  • Force II Flowmaster exhaust system
What's my next steps? Please put them in order, add, delete, and explain why..
  • Underdrive Pulley(s)
  • Light weight jackshaft pulley
  • IC fan
  • 3.73 gears
  • Cold Air Intake
  • PerformanceTransmission Upgrade (What's the best Streeter)
  • Drive Shaft and ujoint upgrade
  • Over Drive pulley (optional]

Thanks in advance
 
Last edited:
Mods

Over drive the blower, make sure the air intake silencer is removed (if you add a cold air intake it will have to come out anyway) Underdrive pullies, and gears (3.27 is 5 speed, 3.73 if auto).

Dave
 
Big Cat Davo said:
Over drive the blower, make sure the air intake silencer is removed (if you add a cold air intake it will have to come out anyway) Underdrive pullies, and gears (3.27 is 5 speed, 3.73 if auto).

Dave
Thanks Dave. The silencer has been out since last spring. I was thinking that the 10% pulley would be a good next step but I wasn't sure if it was better to do the 70mm TB first before hand to allow more air in the intake. Since I got one coming next week, I should have it on and off within an hour. I've already got the steel idler pulley too.
 
Tb

Some pretty impressive times have been run on the stock TB, you need to be moving some serious air before it becomes are restriction.

Dave
 
Big Cat Davo said:
Some pretty impressive times have been run on the stock TB, you need to be moving some serious air before it becomes are restriction.

Dave
That’s great to hear. I guess I'm making the right choices so far.
  • Since I'm getting a 10% blower pulley, I'm thinking that the underdrive pulley would be a bit much for the heads :eek:.
  • I was thinking that a performance transmission/converter should follow and then gears. I currently have a stock AOD.
  • I guess I'll hold off on any intake parts until after the above is complete.
 
Last edited:
Underdrives

Underdrive pullies are for the accessories. The Alternator, and water pump, as well as the crank. It resuces the amount of power the engine uses turing the accesories and allows the power to head to the wheels, it is a fantastic mod, and bang for the buck , one of the best.

Dave
 
Big Cat Davo said:
Underdrive pullies are for the accessories. The Alternator, and water pump, as well as the crank. It resuces the amount of power the engine uses turing the accesories and allows the power to head to the wheels, it is a fantastic mod, and bang for the buck , one of the best.

Dave

Well thanks Dave, it all makes perfect sense to me now. So I guess I'll rework my list, see first post.
 
rickbtbird said:
What's my next steps? Please put them in order, add, delete, and explain why..
  • 10% Blower Pulley
  • Underdrive Pulley(s)
  • PerformanceTransmission Upgrade (What's the best Streeter)
  • Drive Shaft and ujoint upgrade
  • 3.73 gears
  • Cold Air Intake

Thanks in advance

I'd probably do a 5% jackshaft pulley, instead of the 10% OD pulley. If you are still using a stock IC, the 10% will most likely generate too much heat. Even with my Spearco (bigger than stock) IC, my car seems quicker initially with the 10%, but slows down on the top end. Plus the aluminum jackshaft pulley will be lighter than the stock jackshaft.

Underdrives and gears will be the best bang for the buck, I'd at least put the underdrives at the top of the list.

The driveshaft can be moved to the bottom of the list, unless you are planning on some bonsai highway passes at high speed after the gear install, the driveshaft can wait.
 
Kurt K said:
I'd probably do a 5% jackshaft pulley, instead of the 10% OD pulley. If you are still using a stock IC, the 10% will most likely generate too much heat. Even with my Spearco (bigger than stock) IC, my car seems quicker initially with the 10%, but slows down on the top end. Plus the aluminum jackshaft pulley will be lighter than the stock jackshaft.

Underdrives and gears will be the best bang for the buck, I'd at least put the underdrives at the top of the list.

The driveshaft can be moved to the bottom of the list, unless you are planning on some bonsai highway passes at high speed after the gear install, the driveshaft can wait.

Kirk,
Thanks for the advice on the pulley application and I'm thinking things over here.
  • I live in New England and is heat as much as an issue here then in the south?
  • The under drive pulleys are lighter and may make me change my priorities around. I can see your point here.
  • Once the under drive pulleys are added, if I was to convert to a 5% overdrive blower pulley, wouldn't that put me in the same heat situation. So what I’m interrupting is you don’t recommend at 10% over driven blower at all with the stock IC.
  • My AOD is 15 years old. Would gears in the rear put my tranny at risk?

Thanks in advance…
 
Last edited:
Modifications

If you plan on to Overdrive the blower


I would also reccomend installing an Intercooler fan

this will help lower the boost charge temps and will help HP gains
 
I agree with Kurt...gears and underdrives are still the best bang for the buck SC mod. I also agree that if your going to overdrive the supercharger, the best place to do it is with the jackshaft pulley. Start with a 5% overdriven aluminum jackshaft pulley, and if you still want more blower speed you can always add a smaller supercharger pulley.

The gears will place less strain on your transmission, so no it isn't going to hurt anything to add them to a car with a high mileage transmission.

David
 
David Neibert said:
I agree with Kurt...gears and underdrives are still the best bang for the buck SC mod. I also agree that if your going to overdrive the supercharger, the best place to do it is with the jackshaft pulley. Start with a 5% overdriven aluminum jackshaft pulley, and if you still want more blower speed you can always add a smaller supercharger pulley.

The gears will place less strain on your transmission, so no it isn't going to hurt anything to add them to a car with a high mileage transmission.

David

Ok then it's set.. relisting the mods by priority in post 1. Thanks for the advice.
 
Folks,
I got a quote from SCP today on pulley sets.
The Aluminum Jack Shaft pulley is $140.
3-Piece Accessory Under Drive Pulley Set $180.
The aluminum 3-piece Under Drive pulley set is $260.

I also got quotes from ASP
1989-94 3.8L S/C Street Pulley Kit 25% Reduction Crank Pulley, 29% Water Pump, 3" Alt
Part# ASP520425, 182.40 shipped.

I might go for the SPC Aluminum Jack Shaft pulley. I'm thinking that the aluminum under drive set would be real light but would they last very long?

What's your experience?
 
Last edited:
Scott Long said:
Why wouldn't they last long? If you can afford it, buy it.
Well here’s what I’m thinking. Aluminum being a much softer metal then steel would have a tendency to wear easier. Being that a pulley is moving all the time with a belt wrapped around it causing a lot of friction would wear aluminum much faster then steel. Does that make any sense? I'm all for lighter pulley set under driving the system but I'm thinking that these aluminum under drive pulley sets are for strip application only.
 
255lph Pump
Underdrive Pulley(s)
Light weight 5% jackshaft pulley
76mm mass air (perhaps 42lb injectors)/Dyno tune/chip
Cold Air Intake
IC fan

Do a valve body upgrade via Lentech

Based on what you had listed this is what I'd do
 
WinnipegSC said:
the stock tensioner pullies are made of plastic.. i cant see ur fear of aluminum wearing out fast?
Yes the stock ones are plastic, mine are steel. They have ball bearings and weight isn't an issue with Tensioner pullies. It's the first thing I replaced on the car. You may be right, could be I'm concerned about nothing. I have a set (25% Crank 29% Water Pump 3" Alternator 950 RPM )coming from ASP (p/n:ASP520425), $182.40 shipped. I can't see paying the extra $80.00 on an aluminum under drive pulley set because I don't see the real bennifet on the street. I think the gain is minimul. The Jack Shaft replacement on the other hand as far as I can tell doesn't have a steel after market replacement.
 
Last edited:
Actually teh reduction in rotating mass going from steel to aluminum is a great benifit. The ASP pulleys hav ean aluminum crank and alternator pulley I believe and a steel waterpump pulley.

The factory crank pulley is very heavy and that alone make steh UD pulleys worth it.

As for the Jackshaft it is also very heavy as well. Get the 5% and you should be happy..In aluminum of course..And wear isnt an issue
 
DamonSlowpokeBaumann said:
Actually teh reduction in rotating mass going from steel to aluminum is a great benifit. The ASP pulleys hav ean aluminum crank and alternator pulley I believe and a steel waterpump pulley.

The factory crank pulley is very heavy and that alone make steh UD pulleys worth it.

As for the Jackshaft it is also very heavy as well. Get the 5% and you should be happy..In aluminum of course..And wear isnt an issue

What if I was to get a standard size aluminum jack shaft pully and a 10% blower pulley?
 
Back
Top