Thread: Dyno results of ic pump failure before/after
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Old Jan 18, 2014 | 12:47 PM
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JEFASOLD
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Default Re: Dyno results of ic pump failure before/after
Originally Posted by RL67037
OK - I'm going to show my ignorance here. A 65mm pulley is for the S/C I'm guessing which is smaller than the OEM pulley, right?

The 185mm pulley I've seen mentioned in other posts is the crank pulley? And is harder to change and won't net as big of gains as the 65mm as a stand alone mod?

Does the 65mm pulley require a different belt or a pulley saver kit (PSK) that I've read about?

I've seen smaller S/C pulleys mentioned (maybe a 62mm?) but does that make a huge difference from the 65mm? Also, what is the size of our OEM S/C pulley?

Sorry for all the questions but after seeing all of these mods mentioned, I'm a little confused.

Thanks - RL
The disadvantage of the crank pulleys is that the water pump, idler and alternator now run at a higher speed and stress the bearings, hence the pulley saver kits. There are several crank pulleys, the 185 being the biggest, then 181 and 178, while stock is in the lower 170 range, not sure exactly. The 185 will give a gain equal to the best SC pulleys providing boost in the 22 and up range. The 181 gives about 20 psi boost, stock is 14.2. Changing the SC pulley wont require a new belt. I have the 181 crank pulley and that didn't need a new belt, the belt tensioner has a pretty good range of slack that it can take up. It was no more difficult to change the crank unit than the SC unit but, then again, I have a lot of tools, including a short but powerful air impact driver. Oh, a change of 3 mm on a SC pulley is much more significant than a 3 mm change on a crank pulley. It's a percentage thing.
 
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