Under drive Crank Pulley

[Wayne G.]

What is the general consensus on these? Was looking at the Unorthordox
Racing crank pulley. Now from what I can find seem there are those that say
that they are fine no problems (Old school Supra website) then there are those that say NEVER use one (Sonic Supras webpage).
A search of this site did not turn up any info---
What do you guys think??

 

[mkiiSupraMan18]

I'm sure the price would immediately eliminate it for me......... But I'm cheap..... :icon_razz

 

[mkIIIman089]

I can tell you that the General consensus (sp) on them is that they mathematically can cause main/rod bearing failure due to crank harmonics that are not being dampened by the Pulley. From what I know; there are no 100% posotive cases that link the pulley DIRECTLY to bottom end distruction. It always could have been something else as well. If you ask Unorthodox they will swear up and down that their pulleys do not hurt the engine due to the fact that they do not dampen. Believe who you choose.

What other say is probably true. it's easier to run like 1lb more of boost then to risk it with the crank pulley.

 

[Wayne G.]

I can tell you that the General consensus (sp) on them is that they mathematically can cause main/rod bearing failure due to crank harmonics that are not being dampened by the Pulley. From what I know; there are no 100% posotive cases that link the pulley DIRECTLY to bottom end distruction. It always could have been something else as well. If you ask Unorthodox they will swear up and down that their pulleys do not hurt the engine due to the fact that they do not dampen. Believe who you choose.

What other say is probably true. it's easier to run like 1lb more of boost then to risk it with the crank pulley.

Well said. Probably better to safe than sorry. But looking at the "Old School
Supra Website" This guys car is heavly modified and says he has 49,000 miles
with the pulley with no problems????

 

[figgie]

It all depends.

Now oldschool is Larry_A out on SF if i recall.

Toyota and even Dinan (the BMW tuner) has showed what happens in an I6 motor specifically and if you think about it. Not good to eliminate the damped pulley.

Now with that said. Under driving. Absolutely pointless. Slower alternator and water pump speeds. Two of the most CRITICAL components that you DO NOT want to under drive. To do a damped lightweight pulley RIGHT it is going to cost money BUT it has been done before.

 

[souprat]

what about underdriving the ps? i understand why you wouldnt want to underdrive the alt or wp but you can run with the ps totally removed. would that even be worth it?

 

[figgie]

what about underdriving the ps? i understand why you wouldnt want to underdrive the alt or wp but you can run with the ps totally removed. would that even be worth it?

you can't under drive the ps THAT much. UNless you get a 100% custom made damper then you just shot the price up through the roof.

 

[mkIIIman089]

From what i understand anyway; the PS in our cars at speed it taking virtualy no HP at all since its variable force. So thats not even worth it.