Does anyone here have the GP's supercharger pulley dimensions?

 

So guys finally, shall we MCS stock owners consider changing to a 16% or 15% smaller pulley or not??

 

The GP pulley is one and the same as the JCW’s.

 

It is pretty funny... because I put a set of calipers on the pulleys at Dan's shop and did the math and came out with the same result and Dan and k-huevo - and when I claimed it most folks didn't believe me, either. People believe what they want to believe...

 

Thanks again Keith. Someone had told me they were different and the ETK didn't show a p/n for the pulleys to compare. Looks like everything else in the engine kit (other than the larger intercooler) is the same too. I guess the only difference is the ECU program?

 

I´m about to buy the M7 16%pulley. What do you think about it?. Did you try it?

 

i read in the magazine JCW pully is 13.8

 

That's the exact figure Eric @Helix will tell you and show you at his shop.

 

And we should believe every thing we read, right? The actual measurements are posted here, and elsewhere. Do the math. I see this thread is going in the same circles as the rest of them, and there is no point in arguing it, its not a religous or political debate...its math.

 

This post is blasphemous!!! First of all he read it... it's not TV therefor it's totally believable as things that are written in magazines are fact. Second of all... how dare you bring logic onto this website...

 

or worse: math

 

Just measured an '05 OEM pulley at 65mm.

I'll try and get my '05 JCW measurement this weekend and everyone can do their own math

 

just out of curiosity, could some of the confusion be between some people calculation the difference in diameter while other are doing circumference? Just a thought, didnt do the math, but after years of the debate, just wondering... Beecher

 

65mm is pretty much equal to k-huevo's 2.56" - and that's what I measured as well. So far we're all in agreement.

Which is actually good - means we're all measuring the same dimension...

 

If I was a bettin' man, my money would be on a 65mm stock pulley, and a 58mm JCW pulley. But that is just me.

 

Wouldn't make a difference -- the ratio would not change.
Would only make a difference if someone was comparing surface areas of the respective cross-sections as that is not a linear relationship -- but that would really be silly

 

Could make a material difference if anyone measured from the "shoulder" vs the pulley surface. Might make a TINY difference if folks compared the bottom of the grooves vs. the top of the grooves... but shouldn't be material.

 

+1 Ecellent. Encore Encore!

And what is the super secret flash?

 

ok, never thought about that, hahah. Beecher

 

For what its worth, I made my measurements where the belt would ride ... on the top of the groves on the center of the pulley using a calibrated (traceable to NIST) digital caliper. However, the measurements were not made at 20°C (68°F) which is the International accepted standard temperature for linear measurements ... sorry guys

 

I measured the diameter at the land top and when I get some time I’ll measure diameter at the groove. I did measure the OEM Gates (JCW) and the Conti (stock) belts rib height/groove depth and they were both identical, if that means anything on its own. I’m all for repeated measurements and I will revisit a comparison again in a couple weeks.

nafffets, it’s no secret flash, it is from LDG, and I “lucked” (clue) into a version with torque management features before ECU shipping was discontinued.

 

After that we should look into which pulley material will have the greatest lose of boost due to thermal expansion.

 

No Answers??

 

I was in the same boat ,when first got my car last year and the guru's on this board suggested to me to leave the JCW pulley alone . The old threads are here somewhere.

 

OK, so now for a stupid novice question. If you reduce the SC pulley in question do you need a shorter SC drive belt or is there sufficient play in the belt tensioner to accommodate the slack?

Or do you install a proportionately larger SC drive pulley at the other end of the loop?