Perrin Crank Pulley now available
 

http://www.perrinperformance.com/brz...z-crank-pulley

Have any of the tuners swapped out this part yet? Do we need to cut the belt and replace it?

First question, will it not ruin my warranty with Toyota/Subaru? It seems like there is no need to cut anything or replace anything bu the crank pulley. Check out Jeffs blog on your provided link for pictures of the pulley installed.

Ismt the pem part a harmonic dampener though?

If I do the math in reverse (weight:power ratio) they'd have to be adding a little over 7hp for that claim to be true.

FRS stock weight:power = 2758/200 = 13.79
Minus 100 lbs = 2658/200 = 13.29
stock weight and 207 hp = 2758/207 = 13.32

Am I missing something?

I think that would be correct. I wonder how much more weight could be saved by reducing the weight of the other pulleys?

Just remember removing rotating mass won't make much difference on a dyno just like removing your passenger seat won't make any difference different on a dyno. It will however rob less power especially in the first gear or two.

That's probably first gear. As the gears go higher, the engine's proportion of rotational inertia as a part of the total rotational inertia of the drivetrain decreases.

We have done this a couple times recently with mixed results. We have NOT done this on the BRZ yet. We have only been doing long term testing making sure there are no negative effects. Which there isn't. The next time we are on the dyno, this part will be installed and tested back to back. It may not show anything, but for sure you can feel this on the road.

This is partially why it this part is so popular on the WRX/STI engines. Its noticeable, inexpensive, and a piece of cake to install (on a manual).

So thats the same for a under drive pulley kit aswell? Lets say a company claims 8 hp, are they usually claiming that from 1st gear?

Hey Jeff,

Are these lightweight pulley go well w lightweight flywheel?

I know that lightweight pulley & flywheel doesn't go well together

Perrin said in the thread where they posted a million pictures of components in the car that it's not underdrive, it's same as stock diameter. So no, you're not actually gaining power, but you are reducing the rotational inertia of the engine.

As for advertising, I'd guess that most companies would advertise 1st gear since that's where it makes the biggest difference.

They should go very well with them. Sometimes both can cause misfire codes, but not actual misfires. We don't know if this will happen yet as there isn't too many of these out on cars. If you have a lightened flywheel, please hit us up! I would love to get this on your car for some testing.

To give you an idea. Only some EJ20 motors had issues with misfire CEL's from both being installed. Other than that, the 2.5L engines almost NEVER have this problem. I have had about 4 of these with some kind of light weight flywheel and pulley with ZERO misfires, and ZERO problems.

Yup not under drive at all. In the past, we would find situations where this messed up other things like PS, and battery voltage. So we have NEVER made our crank pulleys underdriven for this matter.

On this new engine, there is no PS pump, but now its driving the water pump. There is no way, I would want to slow this down!

Thanks! Currently looking at the all the options of mods. I don't wanna jump the gun... yet lol

I just remembered my friend's GM8 (coupe Impreza w swapped JDM wrx engine) & when he installed both lightweight pulley & flywheel, it gave him misfire, so that's why I asked.

Thanks.

To clarify I did understand this was not a under drive pulley. I was just comparing under dive kits to lighter weight pulleys if the hp gains were greater in 1st gears than say 4th for a under drive kit( crank/alternator or whatever).