I have a 2008 non-S, and I've been looking some ways to increase the horsepower in my car. One of the things I've come across is the lightened crank pulley. I don't know much about how cars work, so this might be a dumb question, but does the lightened crank pulley only work with a supercharger? I've found them on a few websites, OutMotoring and MiniMania I believe, and the product descriptions have been a little confusing to me. The link to the pulleys usually says something like "Cooper & Cooper S," but the description usually only talks about using the pulley on the S.

If it CAN be installed on a non-S, has anyone ever done it? Improvements? Gains? Some sort of review would be nice.

Thanks!

 

A lightweight crank pulley can work on any engine.
-The lightweight material lets the engine spin more freely, allowing more power to be sent to the wheels.
-Sometimes these pulleys are underdriven meaning less energy spent turning the AC, alternator, and power steering pump.

A downside to these aftermarket pulleys is that they don't have harmonic dampening. All engines (except for inline-6s and flat engines) exhibit some type of vibration. The stock crank pulley is harmonically dampened. The lack of harmonic dampening with lightweight underdrive pulleys causing engine failure issues has been heavily debated. Right now with the Z32 (90-96 Nissan 300ZX), it is one of the suspects in at least 4 cases of crankshafts breaking 800+HP engines. There have been no documented cases for catastrophic engine failure with < 800HP for the Z32.

Another downside is the under-driving: less coolant flow for the water pump (if the water pump is driven by the crank pulley, I'm not sure on the Mini, I haven't really looked) and less current generated by the alternator.

 

Thanks. So would you recommend it or not? Sounds like it's probably not worth it.

 

The MC/MCS doesn't have an accessory belt driven water pump, nor are any of the lightened pulleys on the market under-driven, so that's really a non-issue. The stock pulley has a rubber layer, but it's hardly an active dampner, the lighter & better machined pulley should be just fine. There are a couple points throughout the RPM's where the engine resonates and you'll feel some additional vibration & noise, just don't make it a habit to hold the engine at that speed for a long time, stock pulley or lightened.

As for power gains, the main reason for changing the pulley, they will be small, a bit quicker acceleration doing 0-60 due to the reduced rotating mass, but you're not actually increasing HP, so as your speed increases (like a typical 4th gear dyno pull), the gains decrease. A lightened flywheel has a much greater effect because it has a larger rotating diameter.

Another downside is that you're 'modifying' the engine, giving the dealer an excuse to blame your parts in the event that you want some repairs made under warranty. The hassle from your dealer is more likely to be a problem than any real damage ever occuring.

 

The 1 or possibly 2 hp gain that could happen with a lightened crank pulley is a side effect of what it is there for. Its been already that it reduces rotational mass and that in turn increases your throttle response. So its your call you should see any major problems with getting one unless you get some ebay knock off. The only horror story is from a guy by the name William Perdigan was making pulleys for Titans, Frontiers and Spec Vs that were not properly balance and they were causing catastrophic engine failures. Just stick with a reputable company.

 

If you have a turbocharged car, I would recommend it after intake, exhaust, and intercooler.
If you have a non-turbo, I guess you can get it after an intake.

And I would always recommend staying away from eBay knock-offs when buying parts. Please support the innovators and engineers that make the real thing. In this difficult economy, it's tough to come out with something innovative and new when there's someone around the corner ready to copy and undercut the price of your new product.

 

and I would recomend buying this one:
https://www.northamericanmotoring.co...ct/4882/cat/28