I'm interested in doing a 15% supercharger pulley upgrade (either the Ultrik or Alta) on my '04 Cooper S, since it sounds like a pretty low cost way to get 20 more horsepower. I live in California, so I'm wondering if a supercharger pulley reduction, which will increase boost and horsepower, will also increase emissions and potentially cause a problem when I need to smog the car for registration.

Any California Cooper S owners out there who have done the pulley upgrade and can vouch one way or another? Also, which pulley upgrade did you do and did you replace the belt as well?

Many thanks.

 

Are you in California's Smog Check I or II areas? I'm in a Smog Check II area in northern CA. The Smog test I have to do involves testing the on a dyno at two speeds. Also, for those not familiar with it, there is an equipment

My car is new. It's a 2006 so it will be 4 years or so before I have to go to the Smog Check. I had the supercharger pulley installed at a pulley party. I asked the installer and the other guys about their experiences with Smog Check. The vendor said a few guys went to Smog Checks just to see what would happen well before they needed to test. They blew clean, but as far as he knew, they were all Smog Check I tests. A couple of the guys told me their cars were too new so they hadn't needed to test, yet.

The pulley I have is from Webb Motorsports and does not require a belt different other than OEM.

 

If you go with a 15% reduction pulley, you are within ~.4% of the JCW reduction pulley; so most likely, you will pass even SMOG II. Greater reductions and there could be problems. If memory serves, the SMOG test results for the MCS straight from the factory is on the high side of allowed emissions for the S/C 1.6 liter engine.

 

Many thanks for the reply. I too am in Northern California, so I guess I'm in a Smog II zone. Is the Smog II check more stringent?

Also, are you happyu with the performance of your Webb Motorsports supercharger pulley? Is it a 15% reduction?

 

even smog check II only tests percentages, not volume, so the car should do fine. These aren't wide open throttle tests, they are steady state at fixed speed. If you really dive into the motor to change things around, this may not be the case.....

Matt

 

It depends on where in Northern California you are located. The S.F. bay area is definitely SMOG II territory. Mendocino - I don't think so. You can find out fairly easily with a quick look-see at service stations that display the SMOG test placard. If there is a set of rollers in the bay that does the SMOG test, then you are in SMOG II territory.

 

I personally wouldn't take a chance on a 17% or higher reduction pulley. The concern I have is in regard to the additional fuel that is being burned with the higher reduction pulley. (Even at a fixed 2,500 rpm sample; with a 17%+ pulley, the s/c is putting that much more fuel-air mix into combustion.) If memory serves, the MCS is on the high side of HC emissions. Put on a 17%+ pulley, and you could bump into exceedance territory for HC. The only way to conclusively know whether a 17%+ pulley is not going to cause problems is to run a car with a 17%+ pulley through the test and see. Anyone out there that has done so????