sc pulley slippage

supercharged95

Registered User
I've tried asking this before but nobody replied, so i'm assuming i worded incorrectly so i'll try again....
I have a 5% aluminum pulley on my sc and of course it's slipping. I have the smaller gates belt(k080390) and i was trying to also use the larger dayco(89016) idler pulley but it wont fit on that tensioner. anybody have any other suggestions(aside from getting a larger sc pulley of course). the only reason that i really give a rats arse is because (according to my 1/4 times) i'm losing a significant amount of hp(30-40) because of it.
 
What you want to do is buy the standard idler pulley that fits the accessory belt tensioner(alternator, power steering and so on) and mount that to the supercharger idler-that will give enough grip to the belt.
 
supercharged95 said:
I have a 5% aluminum pulley on my sc and of course it's slipping. I have the smaller gates belt(k080390) and i was trying to also use the larger dayco(89016) idler pulley but it wont fit on that tensioner. anybody have any other suggestions(aside from getting a larger sc pulley of course). the only reason that i really give a rats arse is because (according to my 1/4 times) i'm losing a significant amount of hp(30-40) because of it.

I believe part of your problem is you shouldn't use the shorted belt with the bigger idler pulley. I know your old belt is frayed, I have and stock belt you can borrow (old school thing, it's my trunk spare) to test this theory. Use it with the larger idler pulley and see if that works.

Since your car is a 1995, the pulley you are running is 10% for you.

Part of your problem with your 1/4 mile times might be because of your intake temps. If those temps get to high, the EEC retards the timing. I believe I have read a post by "XR7 Dave" where he got a better 1/4 mile time on a 5% over a 10% because of this, on the same day.

I would recommend a DIC and 1-2 IC fan's, and since I am spending your money a shorted AC condenser. :) :)
 
thanks for the help birdman. I thought about yanking off the tensioner, but wasn't sure if it was worth the time.
Mike- it's not because of the belt because i cannot put that idler pulley on the tensioner without the top of the pulley hitting the bottom of the tensioner. I'll try to take it off that tensioner tonight and see if i can't get it to fit!

i'm gonna toss my tranny cooler fan on my stock ic and call it good for now, screw the double ic. there's no way i'm gonna spend 400-500 on an age old design. i'll just save up 6-700 and fab my own fmic :)
 
If you have access to a sand blaster, you could rough up the pulley a little.

There is no way you are losing 30-40hp on account of a little slippage though. I'd just try a new belt. Belts never slip when they are new, it's just that they loose grip kinda quickly. Are you sure you aren't using a 10% pulley? You can't tell just by looking at it. Measure the diameter of the ribs. 2.85 is 10% 2.95 is 5%. Ive been running an aluminum 5% forever and don't have any measurable slip even on an old used belt.
 
I sold him that pulley Dave. It's a BTM aluminum 5%. Of course, according to you, what the hell do I know? :eek: :p
 
I'd get that belt off the car buy new good quality belt, like the GOODYEAR gator back, or the DAYCO poly cog. These are both good belts, and have cross cuts in them to help grip. I'm running a aluminum SC pulley and jackshaft pulley without any slippage. I have a 95, so I know what you are going threw. I used to run the form stocks belts, but they slipped really bad, with swapping in the belts, I never get slippage, even when I tried out a 10%.


Good luck.
 
the way i'm guessing my hp numbers (even though there might be more factors involved) is as follows.
last season (before pulley) I was consistently in the high 14sec range (14.8-14.9) with my best time was a 14.7@93 mph with a 2.2 or 2.3 60ft.
with the pulley i was consistently in the low/mid 15 sec range(15.0-15.3).my best time with the pulley was a 15.0@91mph with a 2.1 60 ft... i'm at work right now, but when i get home i'll check my slips and confirm those ##S tomorrow.
Anyways, I had a better 60 ft but still lost lots of time(in theory i figured i'd be running consistently in the 14.7-14.9 range with a best of like 14.6 or 14.6) and 2 mph in the 1/4, so i was exaggerating the 30-40 hp, but i think i was losing 10-20.

i have to admit that when i put the gates belt on i did notice a difference. One of my friend's cars is about as fast as mine and when we'd race (with my old belt) he'd be pulling on me pretty good(1-1.5 car lengths)and after i put the gates belt on he was not pulling.

I think as soon as i find a way to get a larger idler pulley on I wont have the slipping issues as I'm having right now because I'm still smelling a burnt rubber smell from my engine when I put my foot down for any long period of time.

I've also heard rumors that these aluminum pullies aren't all they cracked up to be.... mostly that their light weight causes lots of belt slipping issues. Is there any truth to this?
 
supercharged95 said:
I've also heard rumors that these aluminum pullies aren't all they cracked up to be.... mostly that their light weight causes lots of belt slipping issues. Is there any truth to this?

I'm also running aluminum pullies both on the SC and the jackshaft. I have no belt slippage problems. Typically additional OD won't make your car faster unless your boost is unusually low. For a stock IC anything over 14psi is generally a waste of time.

Other than your belt slippage, I think you are likely hitting some pretty high ACT's which may be killing your performance.
 
XR7 Dave said:
I'm also running aluminum pullies both on the SC and the jackshaft. I have no belt slippage problems. Typically additional OD won't make your car faster unless your boost is unusually low. For a stock IC anything over 14psi is generally a waste of time.

Other than your belt slippage, I think you are likely hitting some pretty high ACT's which may be killing your performance.


Thanks for the info Dave.... so basically you're saying I need to upgrade to an AR? :)
 
supercharged95 said:
Thanks for the info Dave.... so basically you're saying I need to upgrade to an AR? :)

ACT Air Charge Temperature (sensor)

I believe what he is saying is that you are feeding your car to hot of air because of the pulley.

The 10% pulley is the one that shouldn't be aluminum because of belt slippage. My mistake.
 
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