Has Anybody Run a Larger Pulley?

[Junkyard Dog]

The Whipple Stage 1 pulley is 3.875" - has anybody run a larger pulley, e.g., 4", 4.25", or 4.5"

Whipple's install manual has a chart showing that going from 3.875" to 4" drops the boost from 11 psi to 10 psi.

I am guessing maybe we could get it down to 8 with the 4.25 and maybe 6 with the 4.5"?

Has anybody tried this out?


(before I get "WTH would you do that?" the idea here is extra horsepower for track days without overheating - maybe with headers and E85 and a great tune keeping the fuel and timing in the best places while being aware you may be at 700 horsepower instead of 800 horsepower, but still far more than 480, 486, or 500 (depending upon which car you have and which exhaust) for more fun at the track but none of the downsides of trying to track a supercharged car that is going into limp mode)

The idea is not really all that different from turning down the boost on a turbo car, although swapping a pulley is harder than an electronic waste gate. Once you get the right set up, you can swap the pulley prior to the track day and drive to the track with 700 horsepower (or maybe more, who knows?) ready to go attack the asphalt.

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[robvas]

If you're having heat problems on the track I don't think lowering the boost by 2psi is going to do much

The problem is you're making a couple hundred more HP than the cooling system was designed to handle

The question becomes does the larger pulley physically fit. Is it going to run into other pulleys or the blower or the throttle body or anything else.

 

[Junkyard Dog]

If you're having heat problems on the track I don't think lowering the boost by 2psi is going to do much

The problem is you're making a couple hundred more HP than the cooling system was designed to handle

The question becomes does the larger pulley physically fit. Is it going to run into other pulleys or the blower or the throttle body or anything else.

Ugh. I was not aware of these clearance issues.

 

[Junkyard Dog]

@LethalPerformance posted in the 6g forum that a 4" would fit.

https://www.mustang6g.com/forums/threads/whipple-winter-mode-largest-pulley.92272/

See post #9.

Maybe that is why the chart in the manual starts at 4" instead of 4.25 or 4.5.

That only gets the boost down one psi to 10 psi, though, according to Whipple's chart. I can't see that avoidng a whole lot of heat on a track day, although it might help a little.

 

[Junkyard Dog]

Swift answer straight from Whipple:

"The largest that would fit would be the 4.0, however, we would recommend the oversized heat exchanger to help with temps as well."​

This is specific to the Gen 6 3.0 Whipple, information I included in my question.

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