I realize that a 15% pulley is considered to be a very standard and safe upgrade on these cars. However, the majority of owners don't ever get their cars on a road course. I know that GRM popped a head gasket with a 19% pulley on their MCS project car. What are peoples experiences concerning reliability utilizing a 15% pulley in 20 minute road course sessions, where weak points are more likely to rear their ugly head than in short street blasts.

And what about tuning? With people utilizing chips or AFC's to lean out the A/F ratio to somewhere in the neighborhood of 11.5:1 to gain a little extra horsepower, does this generate too much heat in the kind of conditions that one sees on a road course to remove a significant margin of safety? 11.5:1 is still fairly rich but a FI engine running 1 BAR of boost in the summer heat in road course conditions is a different story than driving on public roads.

 

I have 15% plus a bunch of other stuff ( 209 whp ) and last time at the track we were running 30 min sessions. I had a co driver driving in a different run group so my car was on the track for 2 seccions in a row ( roughly an hour at a time ) and it ran like a champ !! I have already been on the track 4 times this year with the 15% and no problems so far. And I drive a little more than 1.5 hours to get to the track and back.

Definatly dont sweat a 15% pulley.

 

Good to hear, I assumed as much but wanted to get some real world feedback.

So what about tuning on your car? I'm assuming at that power level you've got something done to the engine management. What kind of A/F's are you running? And what kind of temps have your track days been done in?

I'll be doing the first track day for the Mini in August, and in Alabama that means extreme heat. I'm wondering if by leaning out the A/F some I will create more problems than the extra HP is worth. Obviously i'll track temps when I tune it, but I won't be able to simulate track conditions.

 

moderate days, the car was tuned on the dyno using an apexi. I dont remember the a/f ratio. Since the last dyno I have added more stuff so I have to go back and tune again.

 

I also have a 15%, the only other performance mod is the Alta intake. The car ran perfectly! I kept my eyes on the temp gauge, it never budged, even on a 40+minute run. No wierd sounds or smoke except from the brakes . If I may offer some advise. The pulley is nothing to sweat over...watch the brakes. I run the Ferodo DS2500 and cooked them. Also, keep a safe distance between you and the car in front of you (I had a very close call when somebody lost control, they 180'd, right in front of me). Sorry for that, I know you didn't ask-but I wish somebody had told me those two things before my first DE. Have a blast!

 

Thanks, i'm less worried about the pulley than tuning the A/F leaner with the pulley and running it on the track as such.

And I have done track days in the past, i'm well aware of the etiquette and how to prep a car. Just haven't tracked me Mini yet since it is new. But I appreciate the concern.

 

Detlman, thanks for he reply. I'm guessing since it was Apexi tuned for HP, then the A/F was probably around 11.5:1 give or take. The summer heat is the only other issue I suppose.

 

I have the 15%, Unichip, intake and other misc (plugs/wires) and after 2 track days with a total of 11 20 min sessions and the only failure so far was the aftermarket oil pressure sender. I called Autometer about that and they said that the sender failure is common when leaning hard on a 4 cylinder car. They sugguested remote mounting the sender to reduce the vibration it would see. I think I will change to an oil temp gage instead. I also tended to shift a little early, 6000 rpm, rather than clear to redline most of the time. Also, I have been running the unichip on the B map with pump gas without throwing any codes. I will change to the A map as the ambient temp goes up this summer. Previous track days were in the lower 60's to 70 deg.

 

15% pulley, ECU, ect.. and a stock intercooler.

Over 25+ track days (4-6 20 minute sessions/track day)

The hottest track day was at Thunderhill, Willows California during the summer.

128°F track temp and 100°F air temp.

The engine saw normal water temperatures and never missed a beat.

 

Over 30 track days and 92K miles, JCW upgrade @ 18K so 74K miles with JCW and 30 track days with no issues.

JMHO a 15% should present no issue.