Hoping some of you can provide some thoughts on these SC Pulleys.

I have an 2003 S and would like to install a pulley or have one installed next week. This is a daily driver 30 miles one way with 1/2 freeway and 1/2 city. While I would like to get it on the track some time I doubt that will ever happen.

I'm thinking 15% - 17% Alta v2 but the M7 at 16% looks like it might be the ticket for protecting the supercharger and waterpump and still getting a nice bump in power at lower rpm. A search provided a ton of hits but very few related to the M7 pulley's. Any thoughts or opinions positive and negative would be appreciated.

Thanks for your help!
DobsOnly

 

Alta alll the way!

I'm ordering mine next week, and installing it next weekend! I'm kind of in the same boat as you. Same year, same driving conditions, but I do take mine to the track. I was a little skeptical at first, but once i got into it, it was all over! I say go with the 15%

 

I love the M7! a lil extra power, no ill effects

 

Here is my question. I'm undecided between 15% and 16%. I know there's very little difference between the two, but which is the most efficient? I know Webb says 15%, and most agree, but is that just the result of only one 16% option out there (and therefor not usually tested for effic.)? On an efficiency curve where would the two be placed? 16% just a tiiiiiny bit off of the peak?

(I feel like throwing in some more percentage signs... %%%%)

 

Supercharger efficiency is only an issue when running near the top of the RPM range. If you read Randy Webb's comments on this, he explains that the efficiency of the super charger reduces only when it (the supercharger) exceeds a certain RPM. His comments agree with the manufacturer specs. If you're driving on a track, you spend a lot of time in this less efficient RPM range. If you're driving on the street, this shouldn't be much of an issue (unless of course you're driving like you're on a track, in which case it's time to give your head a shake!!!).

 

Understood. And I guess asking for the difference between the two is asinine, given the slim difference.

 

I had a 17% on my 02 S and I clocked 1500 miles a week between highway, City, back roads and the Drag strip on Friday nights. I would also autocross it occasionaly.

Why not go with the guy's who pullied Mini's first HELIX

 

Thanks for the comments here and all that have been posted in past threads!

Being a little conservative and limited as far as disposable income. I opted to just go with the Alta 15% pulley but also ordered the Alta CAI. My decision was based on pricing more so than any discussion or thoughts on a particular brand of pulley or reduction size. I'm figuring that will kick the fun factor up and keep the engine and drive train in a configuration to allow a lot of miles to pile up before a failure.

What I learned was everyone is right

There are a ton of people that say the 15% pulley is best bang for the buck and stays within the tolerance limits of the other components.

Many swear by 17% but it seems it can put you on the edge of the envelope and requires a little closer attention to belt wear etc.

A few less, but still a devoted bunch love their 19% pulley and insist that driving style will determine the impact it has on the systems of the car but there seems to be no question on the potential to cause a problem being very real if the car is improperly run.

As far as one maker verses the other? Well, I've seen very little that would indicate other than marketing there is much difference in performance between manufacturers. Each makes good points on what makes their design better than the competition.

The M7 16% seemed very attractive to me for my application. Had it not been for the difference in price and the availability and pricing of the Cold Air Box at the merchants that carried it I certainly would have had one. The $40 or $50 I saved going the route I did made the difference.

Disclaimer: Take what I say with a grain of salt, I'm not a mechanic, engineer or much of a driver. I’m just another Mini owner having fun.


Thanks again!
DobsOnly

 

One difference between a 15% pulley and a 16% pulley is that the 16% should really be used with a shorter serpentine belt, whereas a 15% pulley can re-use the stock belt if there aren't many miles on it.

 

Yep, I have 44000 on mine so it will definately get a new belt with the install.

DobsOnly