Manny...Why do you

RonzSC

Registered User
Hey dude...
Noticed that you are now signing that you are overdrving the crank pulley. Just wondering why would you want to overdrive that particular pulley?
 
RonzSC said:
Hey dude...
Noticed that you are now signing that you are overdrving the crank pulley. Just wondering why would you want to overdrive that particular pulley?
no belt slipage + i can use a 5% or 10% with it for more boost but mostly because it dont slip belts.
 

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How does that work exactly?

Manny..
School me Obe Juan...
When I use the 5% my pulley is smaller than stock and with a smaller diameter pulley on the crank it would seem to greater the potential for slippage.
You are the Master. I was going to go with a shorter belt for the slippage issue.
 
RonzSC said:
Manny..
School me Obe Juan...
When I use the 5% my pulley is smaller than stock and with a smaller diameter pulley on the crank it would seem to greater the potential for slippage.
You are the Master. I was going to go with a shorter belt for the slippage issue.
ahh misconception smaller pulley,

my pulley is bigger than stock same size as outer pulley,

bigger means more area to grip belt aslo more area means more belt turned per revolution,

I get over 1 inch more belt travel per revolution than stock pulley,

now 5% dont really slip much but a 10% does slip,

so use my crank pulley with your 5% and get muncho overdrive without the slipage. :eek:
 
Wouldn't that be under driving the crank pulley, then? Less turns on the crank, more turns on the blower pulley.

Not doubting that it works, but I believe whenever the blower is over driven, it's slipping at the blower pulley.
 
Teehee, never mind, I just realized the crank is going to spin at whatever revs regardless of the size of the crank pulley :p

*puts down crack pipe* *picks up heroine syringe*
 
the reason the blower pulleys slip is less contact area on a small pulley,

what ive done is the same as the jackshft method it speeds up blower without the smaller blower pully so less slipage, now use a 10% blower pulley a over drive jackshat pulley and my crank pulley and you can roast a chicken on the ic. :D
 
Anytime the ratio is greater than 1:1 you are overdriving the SC. IE the SC is always overdriven regardless of the configuration on the supercoupe.

Jeff
 
The post was to clarify overdrive for others.

I already figured it out for you in the post where you made up the pulley. member?
 
J57ltr said:
The post was to clarify overdrive for others.

I already figured it out for you in the post where you made up the pulley. member?
yeah but I lost it ! so rather than make a fasle claim I just said I didnt know .

and really I dont know I wrote it down and then lost the paper I wrote it on go figure id lose it you said i just found it and edit my post lol
You end up with a 2.793:1 based on a 89-93 pulley.

Stock is 2.77:1

Since you measured with a piece of string (I assume) between the grooves the ratio could be as high as 2.818:1

Jeff
__________________
"The Warnings, Cautions, and Instructions discussed in this instruction manual cannot cover all possible conditions and situations that may occur. It must be understood by the operator that common sense and caution are factors which cannot be built into this product, but must be provided by the operator."
my head if it was not bolted on
 
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J57ltr said:
It's bout 1%

Jeff
are you sure you said the stock pulley is 6.9909 but mine measures 7 3/4 inches across stock and modified 8 1/4 inches across,

the measurement around is stock 22 1/2 inches around flat tape measure layed on top of grooves ,
and 24 1/4 inches around modified :D
 
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You may want to check my math it's in that thread. I came up with those numbers based on what you gave me. I could have screwed up, I've been known to swap a number or leave one out.

Jeff
 
I dont know 22.5 inches + 2 1/4 inches is 7% added dia

I got 24.25 and subtracted 7% that left me 22.55 close 6.5% - 7%
 
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I'm a little tired, but I think that would take a different calculation for using FPM (feet/minute). I do quite a few calculations for FPM in my line of work. I don't have my cheat sheet in front of me but I'll get it later.

My measuements were from what Dave and I both came up with and his measurments were within a few thou of mine. I measured at the peak of the ribs on all the pulleys I have measurments for (except 5%, not sure where that measurment came from).

Jeff
 
Ouch...I hurt myself.

So you are overdriving the crankshaft pulley 1% and you are getting a noticeable improvement in the slippage of the blower? Cool.
I've just gone through a project of my own on the accessory drive pulleys and that was my the catalyst for my interest. I would like to share information with you on machining of the pulley.
 
RonzSC said:
So you are overdriving the crankshaft pulley 1% and you are getting a noticeable improvement in the slippage of the blower? Cool.
I've just gone through a project of my own on the accessory drive pulleys and that was my the catalyst for my interest. I would like to share information with you on machining of the pulley.
well I dont know about 1% it makes more boost than my 5% and less than my 10% maybe due to less slipage? :D

magnum powers is offering to make 10%crank pulleys from alluminum.
 
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you're gotta see my new custom crank pulley

What material did you choose Manny? Did you go with a 3-axis or bridgeport?
Wait until you see my little babies! They are finished and ready to put on the SC for a dyno run.
 
RonzSC said:
What material did you choose Manny? Did you go with a 3-axis or bridgeport?
Wait until you see my little babies! They are finished and ready to put on the SC for a dyno run.
you talking bout the lathe dont know its my next door naighbors. I have a few tricks up my sleave see non tech manny furious/me= faster.
some pics of a old prodject resurected .done this week i hope had to fix some things change others and add a better ic . system,

preliminary testing has 170 deg f air blowing into ic and iced water flowing thru it air exiting ic is 77 deg f now to try it in car bench top testing is never as good as real world testing.http://www.sccoa.com/forums/showthread.php?t=63199
 
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