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free lightweight pulley good or bad


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There are always two schools of thought on lightweight pulleys....First says that "oh thats not what was on it from factory so leave it alone." Second group says "you can get MOAR power from lightweight or underdrive pulleys"

 

Personally speaking on these cars, unless you need to swap in lightweight for a specific reason, extreme modding or race conditions, or your current pulley shit the bed somehow. I'd say leave it as it is. Subaru is one of the few manufacturers I've found that have as impressive if not better quality parts from factory than from aftermarket. But it all comes down to opinions and there are 100's of quotes about opinions and their usefulness.

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Well I put it on and have gone 200+ miles no issues. ive ran them on Hondas in the past did more research and underdrive or lightweight doesn't matter wont hurt your car at all. Its a urban legend. The only only problems people have is cel lights occasionally for misfire but its fake its a ghost misfire cuz its not during combustion. Do research and think about it. U put ligh fly wheel on its gonna change engine rotating mass and so would lighter cam gears. And adding/deleting a/c, power steering. I also read someone had a legacy that had light cheap crank pulley on and had cel once in awhile and then got a grimspeed one and it was fine. Its mostly people w no experience or buying 40$ eBay junk saying my buddy said or my uncles friends brother said. Do your research dont buy junk and do what remember its your car do what u want to it and learn contours mistakes
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Well I put it on and have gone 200+ miles no issues. ive ran them on Hondas in the past did more research and underdrive or lightweight doesn't matter wont hurt your car at all. Its a urban legend.

 

while im not against either lightweight or underdrive pulleys, they really arent urban legend. lightweight pulleys on an engine that has a harmonic balancer will not balance effectively, and will eventually cause issues with the engine, especially if it is operated hard, like while racing. most high end racing engines are balanced internally much better than a production engine anyway, so it may even balance out. underdrive pulleys are not to gain speed, horsepower, or anything like that, they are for allowing the engine to rev higher and not destroy the accessories. so, a sbc that normally redlines at 6500 could be built and tuned to run at 8000 rpms, but the alternator would burn up at that speed. underdrive pulley added, it can still run the accessory at 6500 rpm while the motor is at 8000 rpm. that is their purpose. the down side is that at idle, the accessories rarely turn fast enough to be effective.

 

not urban legend stuff, just not really universally understood.

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An under-drive pulley is smaller which in turn spins the accessories faster. That's why when you buy them in a set, the alternator pulley is bigger. That keeps the alternator from over spinning. Light weight balancer pulleys just reduce rotating mass. I don't have any experience with said pulleys on the H4's but I've used them extensively on sbf builds.
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Well the harmonic balancer is responsible for helping to balance the power pulses of your boxer engine going to the transmission

 

 

as long as you retain the balancer I don't see how any issues could arise other than the ghost misfire codes.

 

is it going to give you a performance or increase in fuel economy not sure maybe slight. let us know.

 

Sent from my SGH-I337M using Tapatalk

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while im not against either lightweight or underdrive pulleys, they really arent urban legend. lightweight pulleys on an engine that has a harmonic balancer will not balance effectively, and will eventually cause issues with the engine, especially if it is operated hard, like while racing. most high end racing engines are balanced internally much better than a production engine anyway, so it may even balance out. underdrive pulleys are not to gain speed, horsepower, or anything like that, they are for allowing the engine to rev higher and not destroy the accessories. so, a sbc that normally redlines at 6500 could be built and tuned to run at 8000 rpms, but the alternator would burn up at that speed. underdrive pulley added, it can still run the accessory at 6500 rpm while the motor is at 8000 rpm. that is their purpose. the down side is that at idle, the accessories rarely turn fast enough to be effective.

 

not urban legend stuff, just not really universally understood.[/QUOT

 

That sums it up... There will be alot of stress added tot he main bearings since the balance will be gone.

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If you want a true performance pulley you will want one of these. I just picked one up for the N/A build im doing. It is only about a half pound lighter buts its the best there is. ATI is used widely around the world on many racing engines.

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Well after about 1200 miles I do paper delivery in this beast 6 days a week I have noticed better mpg, quicker revs, very slight power/accel gain, and easier starts, And no cel or problems besides bad ball joint thats getting done ASAP lol. And I about have a my 5 speed swap parts just need info on electrical aspect of it
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For those who say and think undampened crank pulleys aren't bad for your engine your dead wrong. I've seen actual research in a lab of the effects of installing lightweight and any undampened crank pulleys and not having an harmonic balancer can cause major engine failures.

Each time one of the cylinder fires, a massive torque load is transferred down into the crankshaft causing vibrations and at certain frequencies this vibration can be multiplied tremendously. So much that it can and will cause the crank to break. Having a harmonic balancer reduces these vibrations to the point that the crankshaft can handle them continuously and safely. Do your research and see if any guys with big hp or racing engines for say F1 run undampened crank pulleys. They don't they all use dampened pulleys. ATI makes great dampeners and the one I have on my Supra has been installed for years without one issue.

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For those who say and think undampened crank pulleys aren't bad for your engine your dead wrong. I've seen actual research in a lab of the effects of installing lightweight and any undampened crank pulleys and not having an harmonic balancer can cause major engine failures.

 

i dont recall anyone saying there was no effects, so far everything ive read has been more like "acceptable downsides" than anything. comparing a 2nd gen 2.2L NA motor that will likely never see higher than 6k rpm, and will never see the harshness of a real track to a F1 engine is kind of comical as well, we dont have nearly the needs they do, and can get away with a lot more that they cant.

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You can find it comical all you want. The point I was making was you don't see them using lightweight pulleys to gain power or rev speed nor do any of us big power guys. It's doesn't matter the application all engines produce harmonics. I'm simply just trying to save a person from a headache and if you don't like that the that's your problem. Install all of the pointless mods you want.
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wow, sorry to step on your tail there sparky, i wasnt endorsing or damning the products either way, calm down. my opinion of them wasnt really the subject here, the effectiveness was. while "you big power guys" may not use them, these arent big power cars. they also are not high revving purpose built race cars. they also are a lot more forgiving to things that those purpose built cars will not tolerate. condemning someone because they are trying out things on their <200hp daily drivers that F1 or dragster builders cant use is pointless. getting mad over it is even more comical and pointless. have a beer and relax, brother.
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I personal don't think the subaru pulley on my Ej22 engine is a dampner-it doesnt have an interferience fit. Also in agreement the engine wont see over 6000 rpm. And as my crank pulley is almost 20 years old the rubber ring is almost shot. I have to do a timing belt, water pump,oil pump and cam seals replacment. I'm going to throw a grimmspeed pulley on. ATi makes probably the best racing dampner avaliable-just is way too much overkill for a flat NA boxer engine-just my 2 cents.
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All I hear you saying is blah. Lol

Like I stated and I think you missed it, I am simply trying to help people from having a headache.

Btw I don't drink, I shoot guns and drive my Supra to relax. Not at the same time of course. ;)

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What does the "fitment" of a crank balancer have to do with wither or not it will dampen engine harmonics? The fact of it having rubber and being balanced is what does the dampening. Also it doesn't matter if the engine only revs to 6k or 20k. They both will produce harmonics that need to be kept at a safe level. Even if the rotating assembly is blue printed and balanced more than it comes from the factory, it still will have harmonics because of the force being produced by each cylinder firing.
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What does the "fitment" of a crank balancer have to do with wither or not it will dampen engine harmonics? The fact of it having rubber and being balanced is what does the dampening. Also it doesn't matter if the engine only revs to 6k or 20k. They both will produce harmonics that need to be kept at a safe level. Even if the rotating assembly is blue printed and balanced more than it comes from the factory, it still will have harmonics because of the force being produced by each cylinder firing.

 

A true dampner has to be pressed on to the engine crankshaft to do any "dampening". If it just slides on "Non interferince "fit it will not do any dampening. Of course all engines produce harmonics, my model A doesn't even have throw weights on the crank and just a front pulley and is still running from 1929. with high compression head(6.5 to 1) and twin 97 carbs, produces 85 to 90hp@3500rpm.

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Wrong. Take for example my 2jzgte engine. My pulley can be pulled off without the use of a puller and I know for sure they have actual damper crank pulleys. About 10 years back there was a huge discussion about this subject on a Supra forum. There were a couple guys that had lightweight crank pulleys installed and they ended up having crank issues because of them. So imo your information isn't correct. Even while attending UTI this was a subject we learned about and this is where I seen the lab testing.
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Wrong. Take for example my 2jzgte engine. My pulley can be pulled off without the use of a puller and I know for sure they have actual damper crank pulleys. About 10 years back there was a huge discussion about this subject on a Supra forum. There were a couple guys that had lightweight crank pulleys installed and they ended up having crank issues because of them. So imo your information isn't correct. Even while attending UTI this was a subject we learned about and this is where I seen the lab testing.

 

Pretty sure the toyota engine isn't a boxer style engine.which with opposed cylinders that balance each other out. pulled my pulley off the subaru. after almost 20 years can see where it is starting to slip. and if it does the out come isnt good. Just to clarify the ford model A uses a very heavy fly wheel 65lbs, to balance out the harmonics of its four cylinders. Nice thing about these forums is we can all have different opinions. And I have learned over the years to keep an open mind.:)

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Subaru engines have "pressed fit" balancers. I've replace a few over the years at the shop due to the rubber dampening separating, which isn't uncommon with them. I do agree with your comment of cylinders helping opposing cylinders balance each other out but there's still harmonics.

I also think it is just a pointless upgrade. You don't see any real power gains, just a little faster rev speed but this is just my opinion. Mostly factual though. Lol

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