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i always say toyota !
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Discussion Starter · #1 ·
i did a reseach, no match. i plan to get a aftermarket crank pully. and i found this OBX PRECISION UNDERDRIVE CRANK PULLEY for supra on ebay is a very good price compare to the Unorthodox one. anyone tried this brand? there is not much information posted on the OBX PRECISION UNDERDRIVE CRANK PULLEY there. and the Unorthodox one is saying its 20% smaller, about 60%-90% ligther for the Ultra S version.
 

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iSketch Master!
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9,044 Posts
I dont think its a wise idea to ever go with an underdrive crank pulley. Why do you want one anyways? If you want a different one go with a dampened one, which neither of the ones you listed are.

And something just strikes me as odd. How can something be 60-90% lighter? That's a HUGE difference

Alex
 

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Kirisute Gomen
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When it fucks up, and you're out a significant amount of cash is eBay gonna pay for your motor?
 

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i always say toyota !
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2,761 Posts
Discussion Starter · #4 ·
the aftermarket one will make some extra HP. and a dampened one is not important for my supra. if you know what they make out of a 60%-90% lighter is not a surprise.
 

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LEADED FUEL ONLY
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Never run an undamped pulley on an inline 6 motor. The *harmonics* will kill things in 30k miles or so.
 

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i always say toyota !
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2,761 Posts
Discussion Starter · #8 ·
aljordan said:
Never run an undamped pulley on an inline 6 motor. The *harmonics* will kill things in 30k miles or so.
what things would the harmonic kill? the belt? why never run it on the L6?
 

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Supra TT Senior
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1,886 Posts
GTR-33 said:
Never go with OBX anything on a Supra.
I agree...I thought they just made cheap intakes for civics. Even if I had a Civic I wouldnt use their stuff.
 

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iSketch Master!
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YaosAuto said:
the aftermarket one will make some extra HP. and a dampened one is not important for my supra. if you know what they make out of a 60%-90% lighter is not a surprise.
wha? I wasnt saying it's impossible to weigh 60-90 percent less im saying thats a huuge range for a single part. Do they all weigh slightly different or what. IMO though the extra 5-10hp or whatever it is isn't worth it.

And please tell us why your particluar car doesnt need a harmonic balancer? It puts extreme stress on the bearings in your engine making premature failure a surety.

Alex
 

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i always say toyota !
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2,761 Posts
Discussion Starter · #12 ·
Alx2785 said:
wha? I wasnt saying it's impossible to weigh 60-90 percent less im saying thats a huuge range for a single part. Do they all weigh slightly different or what. IMO though the extra 5-10hp or whatever it is isn't worth it.

And please tell us why your particluar car doesnt need a harmonic balancer? It puts extreme stress on the bearings in your engine making premature failure a surety.

Alex
by how many extra HP is really depending on how many HP is your car making. the harmonic balancer will help on the fan belt stress. i didnot know it helps the bearing stress. what bearing you talking about?
 

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iSketch Master!
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fan belt stress?? where do you get this from? I dont think all these people would say dont run one just to save your fan belt. And since the balancer is attached to the crank these would be the main crank bearings...

and even if it was 30hp gained, i'd rather not worry about when im going to have to rebuild my engine from not running one. Maybe thats just me though.

how bout this go search google for harmonic balancer, crank, crankwalk, lightened crank pulley. Any or all of those together. I think you will come back with far more cons than pros to running one.

Alex
 

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Damn Spaniards
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Main bearings mostly. You WILL destroy your ongine just to gain a couple RWHP? Come on. Don't be a cheap ass Honduh boi ricer.
 

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i always say toyota !
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Discussion Starter · #15 ·
you want what? i really did a reseach from googel with "aftermarket crank pully". and there was a supraforums thread showing there on the top 10 list, and thats the only list is saying there is a problem with the crank pully with no damper on the top 20 list. i didnot look at all the seach. there was no other user reported problems on that thread. as lagtime said its not enough information to prove the non-damper crank pully was the problem in that case. and its hard to understand the non-damper crank pully and light weight flywheel combo can cause problem like that ( clutch break apart ), and extra wear on the engine bearings. about the stress you are talking about. i think the underdrive light weight non-damper pully would free up some stress, cuz its underdrive, light weight, and non-damper. underdrive - it doesnot turn as much, light weight - it doesnot need to pull as hard as the heavy one, non-damper - it doesnot grab as hard as the damper one.



http://www.supraforums.com/forum/archive/index.php/t-4552.html
 

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iSketch Master!
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underdrive means it doesnt turn the accesories as much. Someone correct me if im wrong. Engine speed doesnt change. Lightweight is always good, but I have no idea what you mean by "it doesnt grab as hard as a the damper one."

The link you provided seems to have some good info, but all of it goes against what you are saying. Especially what DT posted. The only person with some kind of reasoning towards yours was tozer, but he himself said he can't prove or disprove whether it's the undampened pulley that causes this.

You can go ahead and put it on your car. If it destroys itself, we told you so. If it never fails, or you never notice any premature wear, then more power to you. Personally though id advise against it for it's minimal gains.

Alex
 

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i always say toyota !
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Discussion Starter · #17 ·
the grabbing i was talking about is the pully grabs the belt. its like a 300lb air pressure tire compare to a 30lb air pressure tire. the 300lb air pressure tire won't grab the ground as hard as the 30lb pressure one. you gain this minimal performance only at the moment you step on the gas hard. i don't think people can feel this, but we can image it. you are right, the crank pully itself would turn the same, but others would turn less. we can gain the HP by others are not working as much. lets say the underdrive is 20% smaller, we can gain back 20% HP of what we lost from the fan and P/S.
 

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Registered
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It's ovious that you have made up your mind to buy this part. We can continue posting reasons why not to use it, but you are just going to tell us why we are wrong. Buy it, and let us know how it works.
 

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iSketch Master!
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^^ exactly.

and why not just run every other underdrive pulley instead of messing with the crank pulley? Im just tryin to understand why you are so adamant on running one. I dont get your analogy though, but it doesnt matter at this point, maybe im just tired. :bigthumb:

Alex
 
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