I'm running both of those combos without issues.
I don't like the idea of such a small pulley on the SC because of the amount of material cut off (is it still safe) and for the increased possibility of slippage.

 

Interesting thread. I have thought the same thing but dismissed it. Maybe I missed something but going a little larger on the crank pulley and keeping the C3 or just getting a 185mm and selling the C3 seems to make a lot more sense. It might cost more but the exploding or seizing C3 could cost huge bucks.

I look forward to the end of this story.

 

the cost is miniscule in comparison to the 181 or 185 coming off the crank from improper install. check the c32 forums and e55 section. more than a few have killed the crank by bad installs. the c3 is a simple install and works like a charm. crank pullies have more power but fueling issues abound there also

 

Yeh, and a volcano could go off and kill the guy. My comment presumed someone other than an idiot would be installing the crank pulley. It was never a debate on crank vs. supercharger pulleys. It was on the wisdom of milling the C3. Just for the record, I chose the C3 over the crank pulley.

 

let's not get "cranky" here...but anytime you push something close to the max...sooner or later something will give....each to their own...but, you can't push it past the fuel needed, or you are back to the lean issue...you just have find that happy middle...where everything comes together...

 

You put cranky and max in the same sentence. I'm calling the ACLU.

 

I know, I am a race ist....lol

 

With all those modifications I would hope so.

 

Hi John, just wanted to know what happened in the end. What amount did you turn down the stock pulley (if indeed that was the route that you chose)? I found a good machine shop that can turn down my original SC pulley. What mm do you suggest I aim for? Is 65mm realistic? Thanks.

 

Hey James, I didn't go that route because I couldn't organize the machinist, I just stuck with my Code 3.

If your going to machine it I'd personally go down to 62mm. The last Code 3 pulley they made which I've got is 65mm which is pretty much on par with the 175 crank pulley.

Now if you machine it down to 62mm you'll be producing boost numbers close to the 181 crank pulley which would be awesome.

If you don't mind me asking how much is your guy charging to do the machining?

John.

 

Hey John,

Now if you machine it down to 62mm you'll be producing boost numbers close to the 181 crank pulley which would be awesome >>> If it can go down to 62mm I will, but I'm not sure it can?? I've been on the forums all night to try and find out. Some think you can't get to 65mm because of a groove inside the pulley. If so, I may just go for 68mm and think about stacking a 178mm later.

If you don't mind me asking how much is your guy charging to do the machining? The owner gave me a 'couple of hundred' as a verbal today while I was with him. (left it with him for a 'day or so' for him to work out). He thinks he can fix up the loose rivets on the backing plate too! Hope so. That means I'll mod the original and keep the one you sold me as the fall-back / spare.

Cheers,
James

 

Sounds like a solid plan. I would mod the original also. If you screw in up, oh well, it's just going to take up shelf space anyway.

 

there was a member who used aircraft quality rivets and repaired his oem pulley. with the groove on the inside of the pulley 62 mm isnt likely. 65mm may be doable

 

Luckily I have a spare to experiment with!

Yes, I'll try for 65mm and see how that holds up.Thanks.

p.s Managed to acquire a tin of Mobil Jet Oil 254 from SkyGeeks.Com recently. 1 x Quart tin. Great service from those guys. MB here in Oz wanted $157 for 125ml (4.22 fl.oz). I got 946ml (31.99 fl.oz) landed for under $50! Go figure.

 

What's this groove you guys keep talking about?

I was curious, so I went over to the closet and pulled out my stock pulley. I couldn't see / feel any groove inside of it. I even snapped a couple photos.




I also grabbed my calipers and did some measuring. I measured the inside diameter of the pulley to be 2.04 inches (51.8 mm) and the outside diameter of the pulley to be 2.92 inches (74.2 mm) and the depth of the belt grooves to be 0.14 inches (3.6 mm). So that means you've got 7.6 mm between the inside wall of the pulley and the bottom of the groves. If you machine that down to a 65 mm pulley, that takes 4.6 mm off each side, leaving 3.0 mm of material between the bottom of the grooves and the inside wall of the pulley.

I'm no mechanical engineer, but I do know that's getting thin. I don't know if you can go any thinner and still maintain structural integrity. Of course, the belt grooves might not need to be so deep. I'm not going outside to measure my belt ribs.


I'm thinking that what we need to do is get someone to shave the supercharger shaft down a few mm's and give us some room to put a smaller pulley on it. Though, that would require fabbing up a whole new pulley assembly, which wouldn't be cheap. It would probably be cheaper to just go with a 181 or 185 crank pulley.

 

James I think you were meant to get Mobil Jet Oil II rather than the "254".

John.

 

Good work on the measurements!

The whole 'groove thing' came from the following:

https://www.crossfireforum.org/forum...c-pulley-5.jpg

It looks as though there is a non-metal / plasti-rubber ring where the bearing sits...although this would I assume be shielded by the thicker width of the pulley's bulbous head...no **** joke intended!

CrossfireKat (who posted the pic) stated that his stock pulley had been turned down to 66.8mm but that a groove he identified prevented turning down further to 65mm. I'll have to ask him/her for an update.

That caused me to search further last night to find any evidence of a minimum structural boundary, but I couldn't find one.

So, I'm thinking of turning down the stock sc pulley to 67mm based on no other solid evidence to the contrary. I've scoured all the threads here and over at MBWorld. This, and your measurements, are the best data I have to go on.

Of course, I have 2 stock pulleys, so I can 'afford' to sacrifice one

 

Mobil Jet Oil 254 is the replacement for Mobil Jet Oil II. I researched this thoroughly before buying

 

Here's an image of a cross section. You can see the groove inside up where the bearing would sit - at the top, adjacent to the belt grooves. There don't seem to be too many spare millimeters at that point! The second image is of a turned down 68.5mm pulley. I am unsure if they are related images. Turning down 3.1mm each side from 74.2mm stock will yield 68mm. I'd be reticent to go farther than that. If the cost of turning down is not too high then I'll sacrifice one pulley to the cause. (If I can find the owner of this image of course, I will ask them the dimensions of the cross section).

C32superchargerpulley_crosssection.jpg

turneddownoemscpulley685mm-1.jpg

 

Might be able to weld up the groove, then have it ground/smoothed out.