If you were wondering, I'm considering having it done, and wondering how difficult it is to do. Flow (Charlotte, NC I think) has offered to install one, and short of that, I'd have to drive to Philly!

You guys have reassured me that it's not rocket science, but that you can't take your sweet time either. (I wonder if you could put together a two-piece stop to help with alignment, so that you could slide the pulley on until it butts up against the stop. Just a thought.)

Randy said it in another thread, for me the magic combo is the pulley and intake. Great bang for the buck. The other thing that has my attention is intercooler mods. Living in Atlanta, dropping the intake temp would be a great thing.

Jeff

 

We must have different keyboard cleaner mine will make ice form if you spray if in one place long enough. Mabey I had an old can that had freon proplent. I dont have any right now to say what was in it. About heating the pulley as hot as I need too to make it slide on its a .003 interference fit, I think I will check, and does the aluminium care what heat you get it up to?
I found the post about the pulley swap its called questions about pulley swap.

 

kite-surfer,

Hopefully you're now using CFC-Free aerosols and cleaning products! :smile:

Okay, time to get technical. The coeficient of thermal expansion of aluminum is 0.0000133 inches/inch/degree F. That means that for every inch of pulley inside diameter, that diameter will grow 0.0000133 inches for every 1 degree F increase in temp. If the pulley ID is 1.5 inches (guestimating here), the ambient (starting) temp is 60 degrees, and you heat the pulley to a uniform 500 degrees, the pulley ID will grow 0.009 inches.

1.5 inches x 440 degrees F x 0.0000133 = 0.008778 or about 0.009 inches

So this should be more than enough to overcome the 0.003 inch interference. If I have the pulley ID wrong, just plug in the right number and recalculate; but I don't think I'm way off. 0.009 sounds like a lot more than you need, but remember, the aluminum pulley will cool very fast in ambient air and you need 0.002 clearance minimum for an easy sliding fit. If the starting interference is 0.003 then you want at least 0.005 of expansion throughout the install process.

As for damaging the pulley, the annealing of aluminum (the process of removing any material stresses and heat treatment) is done in excess of 800+ degrees F and for extended periods of time. So at home-oven temps there's no risk of removing any heat treatment the material may have. I wouldn't leave it in a 500 degree oven overnight, but the ten minutes it will take to heat through is no problem.

Again, best of luck to you,

James

 

>>If you were wondering, I'm considering having it done, and wondering how difficult it is to do. Flow (Charlotte, NC I think) has offered to install one, and short of that, I'd have to drive to Philly!
>>

friedduck,


If you go to Flow MINI (a helix dealer), Dan Zipken is the tech you want to talk to. A good guy and a great tech, a combo that seems hard to find these days. While your there say hello to Bookie Binkly , he is a MINI salesman that has one of our pulleys (and a few other goodies )on his MCS and has been ripping up the blacktop @ VIR on the weekends.