Crankshaft pulley

[Galavoxx]

Supposed 9 hp gain on this pulley. I wonder how realistic that number is?

http://www.injectedperformance.com/V...t.aspx?ID=4277

I like the red. Should fit the Yaris. no?

[acrbill]

Originally Posted by Galavoxx

Supposed 9 hp gain on this pulley. I wonder how realistic that number is?

http://www.injectedperformance.com/V...t.aspx?ID=4277

I like the red. Should fit the Yaris. no?

OMFG. How the hell could they even advertise a 9hp gain. Thats an 11.5% gain in whp (assuming 78whp). The superchargers offer a 30% gain.

How much does the stock pulley weigh?

[Galavoxx]

Looks like the stocker is about 4.5lbs, maybe 5lbs since the pulley claims a 4lb weight reduction. Check the dyno run at the bottom. I know it's a TC but if even half of this is true...

http://www.vividracing.com/catalog/p...ducts_id/10126

[acrbill]

Originally Posted by Galavoxx

Looks like the stocker is about 4.5lbs, maybe 5lbs since the pulley claims a 4lb weight reduction. Check the dyno run at the bottom. I know it's a TC but if even half of this is true...

http://www.vividracing.com/catalog/p...ducts_id/10126

I don't believe that dyno chart for a second.

Also check out this link about undamped pulleys. http://www.suprasonic.org/public_htm...atedamper.html

I don't want to come off as a know it all prick but come on, 9whp out of a 78whp car?

I could believe it if we had a sewer cover bolted to the crank.

[Chris07LB]

Originally Posted by Galavoxx

I'm not that stupid. A lightened pulley wouldn't be as light as an aftermarket aluminum piece but depending on who you know, it would get done fast and definitely be just as strong. Actually, the Yaris pulley is so damn small... doesn't look like it can be lightened.

I didnt call you stupid.

But it looks as if you saw the light, no pun intended, on lightening the stock pulley.

Anyone want to buy a Scion one for 100 bucks?

[Galavoxx]

Originally Posted by acrbill

I don't believe that dyno chart for a second.

Also check out this link about undamped pulleys. http://www.suprasonic.org/public_htm...atedamper.html

I don't want to come off as a know it all prick but come on, 9whp out of a 78whp car?

I could believe it if we had a sewer cover bolted to the crank.

That dude has 700hp!! I can believe that sonic noice/vibration may decrease engine life but I don't believe that article applies to every car across the board. Sounds like he's talking about Supras. 400hz is a very specific number and since most everything in the universe (automotive and otherwise) resonates at a different frequency, it seems like it wont apply exactly the same way to our motor as it does to his. And yes, I read the article. Anyway... ever see that old movie of the bridge shaking apart? That does sort of make me think twice about getting a pulley. Could you imagine, you just sustain the rpms at exactly 4720 for a little too long and then... the motor shakes apart, flywheel and all!! ahhaha!!

As an aside, they sell these things... for those too feeble to go full aluminum: http://www.mythelogy.com/

And...

Read this:

People are getting their crank pulleys confused with the harmonic dampers found on some V6 / V8 engines. "Harmonic Balancer" is a term that is used loosely in the automotive industry. Technically, this type of device does not exist. The "balancer" part comes from engines that are externally balanced and have a counterweight cast into the damper, hence the merging of the two terms. None of the applications that we offer utilize a counterweight as part of the pulley as these engines are internally balanced.

The pulleys on most of the new import and smaller domestic engines have an elastomer (rubber ring) incorporated into the pulley that looks similar to a harmonic damper. The elastomer in the OEM pulley serves as an isolator, which is there to suppress natural vibration and noise from the engine itself, the A/C compressor, P/S pump, and alternator. This is what the manufacturers call NVH (Noise Vibration & Harshness) when referring to noticeable noise and vibration in the passenger compartment. It is important to note that in these applications, this elastomer is somewhat inadequate in size, as well as life span, to act as an effective torsional damper. If you look at the pulleys on some of the imports there is no rubber to be found at all. We have samples of these, mostly from Acura/Honda, the Nissan Altima, 1.8L Eclipse, 2.3L Fords, Chrysler 2.2L's, and 1.8L VW's, to mention a few. This is not to say that with our pulleys you will hear a ton of noise or feel more vibration from your engine compartment. Most who have installed and driven a vehicle with our pulleys will notice the engine actually feels smoother. This is a natural result of replacing the heavy steel crank pulley with a CNC-machined aluminum pulley. NVH is variable and unique to every car. NVH will increase with the installation of an aftermarket intake and/or exhaust, for example. Think of OEM intake systems in newer cars, they use baffles and resonators in the intake to quiet all the intake noise. Aftermarket intakes eliminate these resonators and create dramatic increases in engine noise from the throttle opening and closing. So to most tuners, certain types of NVH can make the driving experience more enjoyable.

The purpose of a traditional harmonic damper is to protect against crank failure from torsional movement. This is not necessary in most modern engines because of the many advances in engine design and materials. Factors such as stroke, displacement, inline, V configurations, power output, etc., do determine when and how these harmonics and torsional movements occur.

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. We hope that after reading this you will understand the crank pulleys better.

[Galavoxx]

Originally Posted by Chris07LB

Anyone want to buy a Scion one for 100 bucks?

Call me crazy but, hell yeah!!

[acrbill]

Besides that rubber ring that I have seen on a few stock pulleys, the actual cast iron plays some part in absorbing high frequency vibration. On the 1st gen Neon there was this huge cast iron block at the attachment point for the front motor mount. Its called a mass damper. Its there to absorb high frequency vibration that would eventually lead to metal fatigue at the attchment point for the FMM.

Don't get me wrong. I had an underdrive pulley on my Neon for over 50k miles.
It served me well. I am all for weight reduction anyway I can get it. I just don't buy the supposed HP gains.

I am far from an expert so take everything I say with a grain of salt.

[Galavoxx]

Originally Posted by acrbill

I am far from an expert so take everything I say with a grain of salt.

x2

I just want a few extra ponies. That dampened lightened flywheel looks pretty good though. Gains look more realistic: 3 to 5whp. Probably more expensive... didn't see a price.

[Galavoxx]

Extra weight on the pulley will also allow for slightly smoother, if not slower acceleration. The motor will also sustain engine speed/rpms more easily. Same effect as the flywheel but on a smaller scale. I little more engine braking would be nice. This car does not engine brake at all.

[PuntangRacing]

Does the yaris have 2 drive belts or 1?

[acrbill]

One belt for the a/c and alternator.

[Galavoxx]

Originally Posted by PuntangRacing

Does the yaris have 2 drive belts or 1?

Ooooohhh... what's that?!!! For Yaris?

[paultyler_82]

I've always used a dampened lightweight pulley, I'm way too paranoid to go undampened, looks like mythelogy is the way to go, unless Fluidampr makes something for us.