Does anybody have these installed yet?Have anybody dyno tested them to see gains in HP?I was wondering how much HP will I see and how hard is the install?

 

Yeah we have plenty of clients with them on the car. You see about 9 HP but mainly quicker throttle response. Will have some pictures and install stuff up on our site at www.vividracing.com

 

I'm having a hard time with the horsepower gains. Explain to me how lighter pulleys, which are not underdrive, give you more HP. Quicker throttle response, OK, but more HP is BS. Prove it, please.

- An interested Engineer.

 

Check the 5 posts by a variety of tuners specifically telling you NOT to use them

 

You do the math engineer. say the torque stays constant but the work can be done faster due to less reciprocating mass. Plug that into the old HP equation and blamo a small risky amount of HP

 

MP5 -

Pulleys are not reciprocating mass, but are rotating mass, when I last checked. A light pulley rotating at 5000 rpms doesn't require less horsepower than a stock pulley rotating at 5000 rpms, does it? So where is the horsepower gain? Prove it, please, and show your math.

An Interested Engineer

 

You are absolutely right and caught me in a brainfart. I dont do math bro try this get a two equal diameter washers one with a small hole one with a larger hole (would be better to epoxy 4-5 together) and roll them both down a slight incline side by side. The lighter (One with the bigger hole is faster though now we are also dealing now with the effects of angular momentum and moment of intertia) So do I think that a few measley HP is worth it? Nope Do I think the concept is sound? YUP

 

I can see how the engine can speed up more quickly due to less rotating mass. Better throttle response same as a lighter flywheel. I can't see increased horsepower on a brake dyno unless the pulley changed the speed of the accessories and reduced parasitic losses.

 

I hope you're wrong, robert5995. Otherwise Volk and Fidanza customers are going to be very upset when they find out that lightened rotating mass doesn't free up torque. Curse that new physics!

 

Gentlemen, gentlemen - we're on the same side here. What we're saying is that less rotating mass = quicker revving up, better throttle response - the same as having a lighter flywheel. Agreed! I was only contending that horsepower testing on a dyno is (largely) static testing - and less rotating mass isn't a factor. Now, I've seen Shiv do dyno testing, and it's not exactly static testing, but it is close enough to static testing that any reductions in rotating mass I don't think would show up on an HP/TQ curve. Anyone have any thoughts on this?
Dale K - this little debate is about NON-underdrive pulleys which are lightened, and which, as you have already surmised, don't increase horsepower.
Ez76 - I've put lightened flywheels on cars before and the results are great, but HP isn't increased - there is just less stuff for the engine to spin up, and the butt dyno feels it. It's like lightening your car - it still doesn't make any more HP, but it certainly goes way better!

 

werd...

 

yeah!

 

Anyone want a set of dirt cheap to do a install with pics and post of results for everyone. We also need them on our site.

Price is $100 shipped. I have black and polished.

 

Horsepower is a measurment of torque VS time. Less rotaing mass can equal more horsepower, but not more torque...

 

you guys still looking to have this done?