15% pulley questions

[cam213]

Hello, I'm new to the site and tried to do a search for this info but didn't find what I was looking for.

I have a 2003 Cooper S w/ about 84,000 miles on it. I just purchased about 1 month ago. I've been looking into doing the 15% SC pulley reduction. Not sure which brand yet, maybe Alta. Probably won't do any other mods besides changing to cooler plugs and changing the belt for fit.

Here are the questions:
Will I have any issues running 91 octane fuel? BMW already recommends 91 from the factory- I'm thinking more boost= possible higher octane needed.

What will this modification do to my gas mileage? My wife drives highway to and from work each day and I'm not wanting to kill the mileage we get doing that. I'm not so concerned about when I go out to play and hammer down- I would assume more fuel would be used then but what about just normal driving?

Will there be any problem adding boost to an engine with this many miles? I don't want to be blowing headgaskets or anything?

Thanks in advance. Any other helpful info regarding this mod would be appreciated.

[MINIAC]

I run 91 octane gas and average over 30 MPG on the highway in my 2002 MCS with a 210 PS Works Kit.

[Jaw_F430]

Quote: Originally Posted by cam213 (original)

Hello, I'm new to the site and tried to do a search for this info but didn't find what I was looking for.

I have a 2003 Cooper S w/ about 84,000 miles on it. I just purchased about 1 month ago. I've been looking into doing the 15% SC pulley reduction. Not sure which brand yet, maybe Alta. Probably won't do any other mods besides changing to cooler plugs and changing the belt for fit.

Here are the questions:
Will I have any issues running 91 octane fuel? BMW already recommends 91 from the factory- I'm thinking more boost= possible higher octane needed.

What will this modification do to my gas mileage? My wife drives highway to and from work each day and I'm not wanting to kill the mileage we get doing that. I'm not so concerned about when I go out to play and hammer down- I would assume more fuel would be used then but what about just normal driving?

Will there be any problem adding boost to an engine with this many miles? I don't want to be blowing headgaskets or anything?

Thanks in advance. Any other helpful info regarding this mod would be appreciated.

I wouldn't worry about running 91 octane fuel as that is equivalent to the UK's 97 octane fuel which everyone runs

In the US I think they use MON and the UK use RON thats why the numbers are different

[cam213]

In your opinion, Is this modification worth the time and money?

[Jaw_F430]

Quote: Originally Posted by cam213 (original)

In your opinion, Is this modification worth the time and money?

I would say yes, Its the first mod I did and I am still running 15% pulley now and my car puts out 270+BHP

[DaFlake]

Quote: Originally Posted by cam213 (original)

In your opinion, Is this modification worth the time and money?

Best first mod that you can do for the money. I run a 15% on 91 with a tune and have not had a single problem. I noticed a slight increase in fuel consumption under normal driving conditions.

[cam213]

Quote:

Best first mod that you can do for the money. I run a 15% on 91 with a tune and have not had a single problem. I noticed a slight increase in fuel consumption under normal driving conditions.

Meaning you get slightly worse gas mileage? Or slightly better? Wasn't sure which you meant exactly.

[DaFlake]

Slightly better to be honest. The car seem to use fuel more wisely. A lot of people have reported this. However, it is quickly lost as you will want to press the gas more.

[cam213]

Well, from that info, it sounds like a go for sure. I don't really plan on having any kind of tune put on it though. I'll be doing the mechanical work myself, and after looking at the instructions, I didn't want to screw with it if it wasn't going be signifant but it's sounding pretty good. Are the NGK 1 heat range cooler plugs the ones that everyone uses? Are any of the pulleys that much better than the next? I really couldn't tell that much difference in the 2 Alta pulley's other than 1 was black and had a fancy little cover that I'll never see.

[DaFlake]

Quote: Originally Posted by cam213 (original)

Well, from that info, it sounds like a go for sure. I don't really plan on having any kind of tune put on it though. I'll be doing the mechanical work myself, and after looking at the instructions, I didn't want to screw with it if it wasn't going be signifant but it's sounding pretty good. Are the NGK 1 heat range cooler plugs the ones that everyone uses? Are any of the pulleys that much better than the next? I really couldn't tell that much difference in the 2 Alta pulley's other than 1 was black and had a fancy little cover that I'll never see.

The Alta pulley is nice as the coupler is the same for both 15 and 17 making it easier to swap to a 17 later down the line if you want. Being in Arkansas, you will be dealing with heat a lot so a better intercooler and plugs are a good start to deal with heat soak. I am using NGK Iridiums that I bought from MINI-Madness and they run great. I also run the MINI-Madness pulley and of all of them that I have installed, the Alta was a pain but probably the least problimatic of them. I say this mainly due to the way that the coupler grips the supercharger shaft.

That being said, they all work about the same when you get down to it and it is just a matter of choice.