Lightweight crank pulley

[wootwoot]

I received my first response about the pulley today. From Subaru no less!

Here it is:

Dear Mr. €|%{*

Thank you for taking the time to contact Subaru of America, Inc. with your message.

Our Technical Services Department has advised that the crank pulley in a WRX or BRZ is a pulley only. The following is Subaru of America's position on aftermarket products:

We do NOT recommend the installation of any aftermarket part into any of our vehicles. Doing so may affect your warranty, but only on related failures. Any problems caused by the installation or performance of an aftermarket product will not be covered by your warranty; thus, you would be responsible for the repairs. As we do not test aftermarket products, we are not in the position to advise as to how an aftermarket product may affect a Subaru.

Thank you, }^%*}^{, for the opportunity to be of service. If you need any future assistance, please let us know.

Sincerely,

John J. Mergen
Subaru of America, Inc.
Customer/Dealer Services Department
1-800-SUBARU3 (1-800-782-2783)
Service Request Number: 1-4733753783

[wlfpck]

This issue has been brought up repeatedly in the past.

It's a $100 pulley that is lighter than stock. Some people swear by these. Others say they'll cause engine failure.


Couple key things that you need to consider is this...

Companies like NST and such that SELL lightened crank pulleys all say they're safe.

There are racing companies that say they won't use lightened/undampened pulleys.

Emailing subaru and toyota will only get you a response from a low level tech/customer service person. They're not getting an answer from the senior techs or the engineers at Subaru/toyota.

Assuming we only go by the current debate... is a $100 pulley worth the risk? This is a moving part. It rotates at a pretty high rpm. An intake sits there and is a tube. It doesn't move. Is it worth the risk? Even if you say that the pulley is safe at 99% rate of success... is it worth it that in the case of that 1% failure, you just voided warranty?

http://www.atiracing.com/products/da...mper_dinan.htm

Now granted... if the original pulley is undampened like it has been mentioned in this thread, then there's not really an issue with replacing an undampened with another undampened. It could also be that Subaru/Toyota overengineered and that the dampening is not needed.

Regardless of what anyone else thinks, the choice is yours to make. Regardless of the evidence, sources, facts, anecdotes, etc. if there is engine failure, people on the forums are going to tell you "oh man, that sucks. Good luck with everything."

All the companies that make the lightened crank pulley are NOT going to give you a new engine. Their warranty covers defects in the pulley. If engine failure does happen, you'll get their we only cover manufacturer defects in the product.

For something like this... my personal opinion is that it is not worth it and I wouldn't get one. I believe that the $100 can be saved and put towards something else.

[Captain Snooze]

Originally Posted by wootwoot

Again, there is a lot of internet hearsay about the pulleys. When engine problems occur, too often people are quick to blame the pulley first, rather than taking the time to look logically into why there was a problem."

Confusing Cause and Effect is a fallacy that has the following general form:

1. A and B regularly occur together.
2. Therefore A is the cause of B.

http://www.nizkor.org/features/fallacies/confusing-cause-and-effect.html

[Captain Snooze]

Don't make any mods because the manufacturer would have already included the bigger engine,wheels,exhaust,turbo,brakes, foot well lights, 400 GW sound system, laser beam headlights. Actually, don't even bother putting fuel in the car because something might happen.

[Captain Snooze]

With apologies to Shakespeare

To fit the mods or not to fit, that is the question
Whether 'tis better in the mind to suffer
The slings and arrows of low lap times
Or to take the wallet against a sea of aftermaket parts
And by opposing the forums? To what gain?
No more posts,and let it sleep,to say we end.

[wootwoot]

From AWD tuning:

Hey Xxxxxx- While there is no well documented proof of the benefits, I'll
say that the results of lack of failures certainly speaks volumes. We
typically recommend having some form of harmonic dampening when revving past
the factory limiter. We have cars that have made over 600whp for years
running harmonic balancers and in combination with frequent tear downs and
analysis. $3-400 seems like a good investment to prevent excessive wear on
a $10k engine. For the most part the OEM pulley may not be intended as a
harmonic dampening device but more like a counter weight for the opposite
end of the crankshaft.

Hope this helps,

Xxxxx

[Captain Snooze]

Originally Posted by wootwoot

Hey Xxxxxx- While there is no well documented proof of the benefits, I'll
say that the results of lack of failures certainly speaks volumes.

This is a nonsensical argument. A does not prove B.
There doesn't appear to be anything substantive in AWD's reply.

[Apoc]

Originally Posted by Monogram

The lightweight crank pulley in the video gains about 200rpm's on the stock pulley from idle to 3,000rpm's At about 3,000rpm's the lightweight crank pulley jumps about 300? rpm's, and then both accelerate at the same pace to redline.

This is under a no-load situation.

Under the normal load of the vehicle, I still do not understand the benefit of a light pulley?

The heavier pulley, accelerating at the same rate as the light pulley above 3,000rpm's, provides more stored energy, which theoretically should improve vehicle acceleration above 3,000rpm's when letting out the clutch. On a manual transmission, the normal rpm range for taking off from a stop when aggressively driving is above 3,000rpm's.

Does anyone have any evidence that the light pulley has any performance gain potential on a stock engine, other than making it rev slightly quicker under no-load situations?

I would also think the heavier pulley would smooth out the power, giving the vehicle slightly better traction control over a broader rpm range under normal driving conditions.

Is there any evidence that the lightweight pulley is a performance improving modification?

I don't think anyone claimed a performance increase that I have seen just better throttle response. I would like to see some evidence of a heavy pulley providing more stored energy and acceleration at higher RPM as this seems to defy any physics I know.

[dave77]

I agree, saying that a heavier pulley will have more of this "stored energy" and then will accelerate faster is really pulling a hat out of the bag. I guess a heavy pulley would be better if the lightweight one weighed 0lbs.

Originally Posted by Apoc

I don't think anyone claimed a performance increase that I have seen just better throttle response. I would like to see some evidence of a heavy pulley providing more stored energy and acceleration at higher RPM as this seems to defy any physics I know.

[Captain Snooze]

I have a challenge for everyone. Read the following story then answer the question.

"Yesterday was a beautiful,sunny day. It was about 26 deg Celsius. My wife and I went for a drive about some twisty roads close to but out of town. I had my window down with the air-con on. (Yeah, weird huh?). I wasn't going fast, just enjoying the day, the car, the company. I was thinking it doesn't get much better than this."

Did I have a lightweight pulley fitted?

[wootwoot]

I get that some of you are finding this thread to be pointless. That's fine. Most threads on this forum fall under that category. But some people seem to enjoy the debate.... If you don't like the discussion feel free to not click on the thread.

[wootwoot]

From Perrin:


Thanks for your interest in PERRIN!

This comes up every once and a while. Typically its a new to Subaru customer, or a dealer that brings up the dampener aspect. For sure there are cars that have this problem and typically they are longer engines with long cranks. There is more vibration going on and twisting of the crankshaft. In the case of the Subaru, its a super short and super stiff crank that doens't have these kinds of issues.

What seems to happen for a specific engine, is people make a solid type crank pulley for a car, and then if there is a problem with removing the dampener (not balancer like some think), then it becomes one of those things you don't install. The Subaru engine has been around for more than 15 years and not only have we been making crank pulleys for 10 years for them, there were many Japanese companies making them prior to us. It really comes down to track record for that part. We have never had a problem. There are thousands and thousands of cars running them and many of them are track guys with ZERO problems.

Also keep in mind that the "Dampener" is tuned to a specific frequency. When you change a clutch, or flywheel, or pistons/rods, then the frequency its tuned to, doesn't apply.

What we say to customers looking to buy it, is the effect is just like adding a lightened Flywheel to the car, but not quite as drastic. Are there other parts that gain more HP for $100? Realistically the only other part i might suggest is an EBCS, but this requires ECU tuning to be able to use, making it cost a lot more than $100. I do think your choice is a good one for sure. If you have more questions, feel free to shoot them our way!


Chris Cone
Tech Services
PERRIN Performance™
AIM: altaperrinsales5
1-503-693-1702
www.perrinperformance.com
Become a PERRIN Performance Fan on FaceBook
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[Captain Snooze]

I much prefer Perrin's reply to AWD Tuning. Perrin's reply has some statements that are not ambiguous.
- "In the case of the Subaru, its a super short and super stiff crank that doens't have these kinds of issues"
- "There are thousands and thousands of cars running them and many of them are track guys with ZERO problems that can be attributed to the fitting of a lwp". My bold.
- "Also keep in mind that the "Dampener" is tuned to a specific frequency."

[tennisfreak]

I think that until I go forced induction I will be more than happy, and feel safe, with my lightweight pulley install.

I dont care if its placebo or not, I like the way my car feels with a full pulley kit on it.

If my engine blows up on me then I will gladly come on here and admit to being a dumbass and advocate not putting them on your car.