OK, here is an attempt at some clarification....

Underdrive means to slow down.
Overdrive means to speed up.

Putting an underdrive crank pulley on a supercharged car would slow all accessories down, including the supercharger which is also an accessory itself.

putting an overdrive crank pulley on a supercharged car will speed up the supercharger and increase boost. another method of getting more boost would be to replace the pulley on the SC itself with an overdrive pulley. This pulley on the SC is the one that is the so called tamperproof pulley.

So what do we do if we do not want to mess with this tamperproof piece? We get an Overdrive Crank pulley kit. Like the one mentioned earlier from www.NonStopTuning.com

And I can tell you from first hand experience, an overdrive crank pulley will not speed up the water pump or any other accessories so much that anything bad will happen as a result. ask the hundreds of Supercharged MR2 owners using overdrive NST pulley kits for the past 2 decades!

 

You guys won't regret it - Boost changed my life

 

im too lazy to read to see if anyone put the same thing im about to, but good luck with it. i hear alot of bad things about the TRD sc. friend had it and it lags alot. doesnt really kick in till about 3-4k rpm, not sure why, but it was wierd. you may want an over sized pulley for more boost, and a top, or front mount intercooler to help it along. good luck though

 

Was this on a tC and did he get the reflash done?

 

interesting that they call it an overdrive pulley. I have always heard them referred to as underdrive, but regardless of the name, the idea is, the pulley increases the speed at which the belt is being turned per engine revolution, which thus increases the spool on the turbine, thus increasing boost.

Hell, for all I care, they can call it a "tea-bagger" pulley. As long as it does the job, I don't give a crap

 

 

it was on a corolla S but still i heard lots of similar responses from all trd sc kits

 

yeah saw that.

 

That's isn't correct. It just needs to be broken off to be replaced, in which case Toyota will know it's been tampered with and be able to void warranty. If Toyota needs to take the pulley off for some reason, I am sure they would put a new cap back on it.

 

Maybe I wasn't **** enough with my response. It should have read...