Can anyone tell me what the stock size upper Supercharger pulley is on the 2015 xkr 5.0?
I have to replace my coupler and therefore I’m going to need to put a new pulley back on. however, since spending the money anyway, I was wanting to go a LITTLE bit smaller than stock, SO NOT EVEN AS MUCH AS THE NORMAL 7.5 OR 10% SIZE DECREASE.I already have the larger lower crank pulley, I don’t want to get into overheating issues so I’m looking for some advice. And yes, I know most of you will say well, Stay with the stock size then, but I already have a higher flow pump and Paramount intercooler and and possibly going to be adding a meth/water kit down the road later if not sooner- and as soon as this is finished, I have a tune from VAP.
So the question is, does anyone make an aftermarket upper pulley or one that would interchangethat would fit and just be marginally smaller where I’ll only increase the boost slightly? I don’t need another 20+ HP or so but it would be nice that I get something for the money even it was only a couple PSI’s.. Living in Kentucky you never know when a little bit is going to come in handy, since we always run from the cops for at least a mile or so. It is an unwritten rule and accepted common practice that goes back to the bootlegging days. Most of the unmarked cars are black mustangs, so even though unmarked, they become instantly recognizable, and as you pass one, it’s almost like waiting for the lights at the drag strip to turn green. At the first glimpse of blue, you immediately take off for the first side street, gravel Road, or exit Into the backwoods. If they start to gain on you, you pull over. If they don’t and you’re pulling ahead they will stop after a mile or so and give up. And the last thing I want is a redneck Mustang catching up to me because I overheated. My pappy would tan my hide if I let that happen! And if I was running a meth kit here in Kentucky, they would probably get me for trafficking and I’d spend at least 90 days in the big house until these rednecks figured out that the meth I was running wasn’t the kind of meth they thought it was….

 

For the record, I’m leaving my 08XKR completely stock.
But I also find your experimental upgrades fascinating to read. Keep’em coming!

 

Well, I seem to be going down the rabbit hole and every time I’m told you can do this upgrade and it doesn’t cost much. There’s always something else that has to be done because of that upgrade or additional tools or belts, etc. at this point I might just go buy a rice burner like a Honda Civic, put one of those high shrill whining, exhaust on it and call it a day

 

I haven't subscribed to a thread in a long time, but, bootlegging, "my Pappy", running from cops, etc? I'm in..

 

IIRC, when you run both a smaller upper and lower pulley you probably need to look at upgrading your tensioner as well, as the lower belt wrap can cause slippage. I would have a think about pros and cons of changing from stock size as you will be adding boost and heat. What you've stated you're after somewhat contradicts - on one hand you want more boost and are getting a power tune, on the other you don't want any further cooling issues while running WOT.

I would say just go the whole hog and get 7.5% smaller pulley (which will only increase 1-2ish PSI anyway) and aim to get water meth. Your upgraded intercooler should help prevent some of the downside of extra power. Or just perhaps don't run from the cops!

 

Looks like the 3.0L uses a 62mm pulley stock. VAP has a 58mm version for around $320.
The stock 5.0L uses a 66mm pulley.

Good point about the uprated tensioner which also leads into the electric vacuum pump to replace the gear driven one on the front of the engine.
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the stock is 3.3” which is 83mm isn’t it? On an xkr

 

Interesting... If not an xkr, a Honda Civic... Haven't heard of that one before.