Sc Pulley Size Questions

darkstar_one

Registered User
Hey, what is the stock diameter of a SC pulley?

89-93:
94-95:
5%OVERDRIVE:
10%OVERDRIVE:

thanks.

one more thing, were do you measure the size? on the ribs or the lip on the edge? thanks.
 
Would you measure at the top of the rib, or the gap in between? I've got a pulley that I've been trying to figure out what it is. We 'eyeballed' it next to my friends 10%, and it's noticeablly smaller than that.
 
JeffTBird93 said:
Just checked it with a set of digital dial calipers...best measurement I can get seems to be around 2.78-2.80...?

I'd say it is a 10%. My 5% isn't the size listed above, it is a little smaller. What was listed above is the sizes I have seen over and over on this site.
 
I was thinking it was a 10%, just never really seen exactly numbers like you posted before, so I figured I'd measure it up.

Is there any point in running a 10% on a stock engine? I mean I have a 5% now with no problems, but would a 10% just be pointless with stock heads? Headgaskets have been done so no problems there. So would I see much more of a difference with the 10%...I plan to have a full exhaust and intake within a few weeks for a little better airflow. Still a little new to modding these, lol.
 
so kool then, i guess i picked up a 10% pulley for 50 bucks, thats freaking sweet, i measured it at the ribs and i get 2.78 to 2.82, so it must be a 10% overdrive... nice... time to Powder Coat, muahahhahahahahhahahha, i guess harmonic balancer next then intercooler setup....
 
JeffTBird93 said:
I was thinking it was a 10%, just never really seen exactly numbers like you posted before, so I figured I'd measure it up.

Is there any point in running a 10% on a stock engine? I mean I have a 5% now with no problems, but would a 10% just be pointless with stock heads? Headgaskets have been done so no problems there. So would I see much more of a difference with the 10%...I plan to have a full exhaust and intake within a few weeks for a little better airflow. Still a little new to modding these, lol.

As long as you get the exhaust done, you'll be ok with the 10%. Just be aware that with a pulley that small, the chance of belt slip is always a concern. It will just bring the boost in quicker than the 5% does and maybe give you another 1-1 1/2 lbs. of boost.
 
nah its steel, its pretty heavy, i guess i can cross drill it to lose some weight, ima powder coat it, and put a bigger idler pulley, that 3inch idler pulley,

anyone know the idler pulley number for that 3 inch pulley?
 
JeffTBird93 said:
I was thinking it was a 10%, just never really seen exactly numbers like you posted before, so I figured I'd measure it up.

Is there any point in running a 10% on a stock engine? I mean I have a 5% now with no problems, but would a 10% just be pointless with stock heads? Headgaskets have been done so no problems there. So would I see much more of a difference with the 10%...I plan to have a full exhaust and intake within a few weeks for a little better airflow. Still a little new to modding these, lol.

Jeff,

You should get the exhaust freed up before you put on the 10%. Do a search on resonator. Once that has been replaced, you should be good to go.
 
Newb here - looking for info on these pulleys. What are some sources of the various sizes of pulleys and what is required to swap them. I know the M112's are press fit and require a puller / installation tool - how about the M90's?

Thanks in advance for any info you can give.

Bird963
 
90blkbrd said:
Jeff,

You should get the exhaust freed up before you put on the 10%. Do a search on resonator. Once that has been replaced, you should be good to go.

Yeah that's what I meant by I'll have one within a few weeks...should've said I would be waiting til then to put the pulley on. Setup is no cats, no resonator, with Flowmasters out back.
 
bird963 said:
Newb here - looking for info on these pulleys. What are some sources of the various sizes of pulleys and what is required to swap them. I know the M112's are press fit and require a puller / installation tool - how about the M90's?

Thanks in advance for any info you can give.

Bird963

Yeah, I three jaw puller works best.
 
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