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Some of you have probably noticed already and I think some have even ordered it, but we have now officially released our new 2-piece upper pulley option, also including the Grip-Tec coating. There are a few advantages to this setup - aside from the Griptec surface treatment which helps combat belt slippage as the belt wears.
The 2-piece design also helps with installation. The JLR upper pulley calls for a LOT of interference between the shaft & pulley to stay on. In the past we even had shops who determined that our pulley had too much interference and milled a couple thou out of the center bore, only to have the pulley come flying off. So this makes it challenging to install as it needs to be properly heated to a minimum temperature and not just in the contact surface but evenly throughout in order to expand fully. By using a 2-piece design, the amount of material that needs heating is greatly reduced and this makes the process much quicker, and easier to get the required heat throughout the entirety of the material.
This updated pulley is now offered in place of our previous 1-piece version on it's own, and also as part of our pulley & tuning packages, and is currently discounted as part of our Black Friday/Cyber Monday Sale.
I must be missing something on the dyno results. If I look at the peak horse power of 375hp at the wheels, and the tune plus two pulleys should yield 475hp this works out to a 27% driveline losses. Previous threads had this closer to 15%. What am I missing?
I must be missing something on the dyno results. If I look at the peak horse power of 375hp at the wheels, and the tune plus two pulleys should yield 475hp this works out to a 27% driveline losses. Previous threads had this closer to 15%. What am I missing?
Previous threads? Meaning prior dyno results we posted from other dynos?
Other dyno results are meaningless to compare in terms of losses or outright outputs. People like to go 'dyno racing' and claim that their car has XXX WHP but it's a foolish comparison. For example, some of our past dyno results for the crank pulley and tune on Lance's V6 were done on a Dynapack - that's a pod dyno bolted to the the hubs, so you have removed the rotating mass of wheels & tyres, probably 100lbs+ and you're not spinning rollers etc. Those types of dynos always show way lower losses. The local dyno we're using is a Superflow (loading dyno) and we've seen extremely consistent results on it.
Stuart, I am referring to something you wrote on another thread. I am not being difficult just trying to understand:
"Hi Guys,
Great results and thank you for going out and doing this on your own, to verify the gains for other people.
A couple of notes - the drivetrain loss isn't 20%. You can show a rough estimation of the drivetrain loss by dividing your 'before' measurement against the manufacturer's stated output. Yes, totally possible that the stated output isn't correct etc. etc. but we're talking about some reasonably accurate figures here so assume it is making 340PS (335BHP.)
335.35/290.54 = 1.1542. So assuming the output originally is as Jaguar stated, you need to multiply your WHP result by that number to get the crank output.
1.1542 x 367.89 would put you right around 424BHP, for a gain of 89BHP. I would say that's a little higher than I might expect to see but it certainly shows our conservative estimate/quote of 416BHP based on the XF-S we developed on is achievable.
Either way, 77WHP and 103WTQ at $995 for our regular price is probably the least expensive HP you will find anywhere. At our current launch special pricing of $697 - on offer until January 31st... well....
12-02-2021, 03:09 PM
VAP Upper Supercharger Pulley Updated Design
