Is this pretty easy to do if you're already in the engine bay doing the reduction pulley install? Will I need a new belt with this and the 15% pulley? Has anyone kept their harmonic damper on there, or is it okay to leave off, as stated on the detroit tuned website. I assume it would be if they say so. Just trying to get some input.

 

I used the stock belt with my 15% and 2% Alta pullies.

 

The crank pulley is rather easy to install (much easier then the SC), but you do need some special BMW tools to do it. (About $60 worth). The only similarity in changing the crank pulley and SC pulley is the removal of the belt. You won't be saving time or work if you do them together.
Crank pulley "replaces" the harmonic, so it must come off (if that was your question.
I use the JCW belt as it is a bit shorter and helps keep the tensioner away from my 3% crank pulley.
Oh, and yes, I would recomend the JCW belt with JUST the 15%, but it's not nessasary and I would bet that 90% of the people using JUST the 15% are on stck belts.

 

many thanks for the input

 

onasled,

Is your setup a 15% sc with a 3% crank pulley?

How much was the JCW belt?

Thanks

 

Onasled
I am using the JCW belt too 16%/2% M7 combo. Hope this belt will out perform the Napa belt.

 

Yes, I use the 15% + 3%.
I don't remember the cost of the belt as I just order it without asking ...
Think it's in the mid $20 range.

 

Saddan
I too paid $25 for the belt.

 

Onasled,

I'm planning to use a -16%/+3% combo. I'm gathering that if I switch to the JCW belt, that will help with clearance, right? Also, are you running the stock tensioner?

 

Yes, stock tensioner. Is there something else out there? I know that GT makes that retainer part which is a good idea. Don't know if it works with a 3% crank though.
A JCW 'might' be tight with a 16+3.

As some may know I have already lost a belt during a track run. It was gut-wrenching to hear that tensioner grinding away the Alta aluminum pulley. This was due to a loose crank pulley and was my error when installing.
Had a new belt on and cleaned up the pulley with a ladies emery board and was out for the next run. ...
By the way .... the video if you haven't seen it.

 

onasled,

Where did you get the crank removal tools? I called my local dealer and not only did they not have the parts but he quoted $160 and wasn't sure how to order it.

Would a regular pulley puller work? What's special about the MINI specific tools? Could you post some pictures of the tools?

Thanks for the help. I hope to install my 2% pulley this weekend if possible.

 

I'm using a factory belt with mine. My install was done at the same time as the 15% pulley- took about 3 hours for everything.

 

Well I tried Classic BMW, (NAM vendor), and their price was $65 for the puller and $58 for the install tool. They also don't have them instock, I guess not too supprising considering they are tools the dealer wouldn't expect the average owner to need.

Any help out there for finding the source for the $60 tools? If not, it's time to make something that will work. I hate to spend almost as much for the install tools as the crank pulley cost.

 

I got mine for a low price at the Hartford CT dealer.

 

Which item gives a bigger performance gain, the 15% SC pulley, or the 3% crank pulley?

A 19% pulley would give MORE boost than the 15% pulley, and thus more power right?

And at what SC/crank pulley %'s do you need to consider other mods, like bigger injectors etc., beyond the standard intake/exhaust, to actually see the 16-19% pulleys show an increase in performance over the 15% (assuming the 15% is kind of the baseline pulley size upgrade).

 

If you are looking for the most effective combo use a 17% sc pulley and a 0% lightened crank pulley. Some are going to say different but thats ok.

 

Or a 15% SC pulley and a 2% crank pulley.

Maybe a little easier on the belt as the 15% pulley is bigger in diameter. Should be the same performance (17% total).

Does anyone have a picture of the factory install tool?

 

nope I would go with a 17% and a 0% there is reasoning behind it, the power gained by the oversised crank pulley seems to be negated by the drag from eveything spinning faster, I have clearly seen it on 2 different cars, mine being one of them.

 

Wow, that's the first time I've heard of that. Not contesting what you've seen, just haven't heard of that effect before. It certainly puts a 'different spin' on things, doesn't it?

 

The alternator would be spinning faster all of the time but the AC would only affect output when it's on. The water pump is run off the SC so that's a push between these two variations.

How could the parasitic loss from spinning the alternator be that much HP? At least 3hp to 5hp as a guess? Sorry, doesn't sound quite right.

In my case I already have the 15% pulley and it's one of the early versions that are pressed on so no easy way to change it. It would be interesting to do a direct comparison. Any volunteers? :smile:

 

I cant tell you why but I can tell you what I saw twice. My car actually pulled LESS with the 3% than without it.

Do the math any way you want but these are the real world #'s I have seen personally.

You would be surprised to know what other car saw the same results with the crank pulley.

 

O.K., so tell us already

 

not this little red hen how's it goin greg? Jock

 

Ya know I would love to say but it sould only cause a shi*t storm.

 

thats ok sheit storms happen here aaaaalll the time, jus wouldnt b "NAM" w/out them!!!!