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slowpoke
08-01-2007, 11:45 AM
hey all, i just installed a 10% overdrive pulley on my 90sc 5speed, everthing else is all stock. any1 know what the hp gain to rear tires might be?

sccrewzer
08-01-2007, 11:57 AM
You do got an upgraded exhaust dont you? cuz if you don't yor gonna blow a head gasket. if you do i'm guessing 10hp more than what you got now just a guess.

Merlon
08-01-2007, 12:01 PM
its all a guess till you get it dynoed...and if it is o/d 10%, stock, you may want to look into new HGs soon.

your going to be needing them...this is a caution.

get better downtubes and HF cats. the intercooler wont be able to handle your pulley on a hot day...put a fan on it, or better yet, get a better intercooler. and use some royal purple and mix it in with the coolant.

as for hp..like i said, what is it worth if someone guesses.
you car is probably pulling timing like crazy in the summer heat...

slowpoke
08-01-2007, 12:01 PM
still running both cats but as for the rest its all costom with flowmasters:cool:
boost is 13psi now with the od pulley to, is that about what is should be?

Merlon
08-01-2007, 12:09 PM
no cats, 2.5 downtubes no resonator, 2 magnaflows and got 14psi...no pulled timing, no changed hgs...i had a good fan on the intercooler, the LS fan was on all the time, and i ran 60/40 water coolant....and watter wetter. never overheated. this was in a 90..and overdriving in a 94/95 is going to be worse for you if its still that stock...like a 14% o/d

what year is your car?

but different supercoupes make different power with the same mods.
i myself blew a few oil seals...was on my 3rd s/c...yours might need rebuilding., or buy a spare now..

slowpoke
08-01-2007, 12:17 PM
mine is a 90 sc 5speed, the cat bodies are there not sure if they have been punched or not, i havent checked them yet. the only other mod is a k&n filter in the stock box. in 90+ heat it'll run at normal temp with stock cooling system. however i dont really get on it very much due to my 1 year old son is usually in it with me. if the cats r not punched would it help to punched them and also would that cause for any problems with the o2 sensor or will it be ok with the reduced backpresure?:confused:

thunderkid84
08-01-2007, 05:27 PM
ok, so just to recap, u have the 10% OD, a flowmaster cat-back and a K & N panel filter, correct ?

your next upgrades should be :

an IC fan
custom downtubes to change the angle (with or without cats)

like everyone has said, your SC is making too much heat for the stock intercooler to handle and the EEC is pulling timing because of it.

i just think slapping a 10% OD on an otherwise bone stock SC is really asking for it.

hell, i have full exhaust, ported heads and intake, FMIC, raised top and im only OD'ing my 94 blower 8%. (prolly should be more but we'll see)

slowpoke
08-01-2007, 07:42 PM
i just tossed the sc up on jacks to get a clear look at it all, it has what looks like lil headers with the downtubes going in a 45% angle into the cats, 2.5 pipes from tubes into cats then from cats to a single 3 pipe to the back then into duel 2.5 pipes and 2 flow masters. now the baby headers at a 45% angle is that what u r saying or is there some better manifolds to use?:D

btw: is there a good sight to go to for the IC fan? and also i just got this car not to long ago so yes the exaust is something im just now looking at since it appears that it is somewhat critical as per the heads from what all r saying so far :)

deepbluesc
08-01-2007, 07:55 PM
And gals;) You need to understand that every motor is different. I don't think it's fair to tell everyone they're gonna blow HG. I'm still on the original engine with now 98k on the clock. I put a Flowmaster Force II system w/stock cats and went to 10% od on the blower and I STILL have the original HGs!

I'm sorry, but it's beginning to remind me of this administration and 'terrorists'!

Ironsam63
08-01-2007, 08:30 PM
Those stock exhaust manifolds are just fine for the "STOCK" engine that you have. You outta change those original cats with high flow cats to release the heat. As far as the 10% od pulley I would not do it even with new exhaust, with stock heads and stock motor,still asking for trouble. The rest of your exhaust is good. With the stock supercharger you will have to rebuild it soon ( bearings, couplers and grease). I learned from an old SC guru in northern IL, that if you change the other pulleys from cast iron stock pulleys to lighter in weight pulleys (water pump,jackshaft, alternator,powersteering pump) that you will get the same if not more hp from freeing up all that power it took from spinning those heavy stock pulleys, and keeping the stock sc pulley. Without the worry of blowing your heads. Same HP - less problems. A little 4 inch fan from autozone is perfect for IC cooling.

fturner
08-01-2007, 09:06 PM
You might want to say 8" fan. The IC is about 8" wide ;).

Schiller park eh! I'm headed there twice this month on business.

David Neibert
08-01-2007, 09:49 PM
hey all, i just installed a 10% overdrive pulley on my 90sc 5speed, everthing else is all stock. any1 know what the hp gain to rear tires might be?

Around 15 if the belt doesn't slip.

David

Merlon
08-02-2007, 11:00 AM
and buy a fan from http://www.spinningwheels-sc.com

S_Mazza
08-02-2007, 01:01 PM
i just tossed the sc up on jacks to get a clear look at it all, it has what looks like lil headers with the downtubes going in a 45% angle into the cats, 2.5 pipes from tubes into cats then from cats to a single 3 pipe to the back then into duel 2.5 pipes and 2 flow masters.

This does not sound like a stock exhaust. So if those are really 2.5" downpipes, then I doubt that the stock cats are still on there. So everyone can stop warning him about them.

Tickler
08-03-2007, 02:23 AM
If you think the stock HG's are going to hold with a pulley, you havint driven your sc long enough. I blew mine at 100k miles with no pulley, its a fundamental design flaw, not luck of the draw.

I'm not a total nay-sayer I do have these suggestions;
1. Insulate your lower IC tube somehow, be careful with fiberglass it'll soak up fluids and catch fire at the least convenient moment.
2. Switch to colder plugs & gap them appropriately.
3. Get some more air moving through your rad & IC, thier undersized and overworked.
4. Get your fuel system "tuned up", do a cylinder balance test or something, leaning out is no fun at all.

These should help with pinging alot, if you ever and I mean ever hear it ping, back off the gas & hit up the forums yo'.