Today I joined 15-20 other MINIs for a “dyno day” at YarrowSport, organized by Rich who runs OceanStateMINI. Various MINI Cooper S were tested, equipped from straight stock through pulleys, intakes, exhausts and engine reprograms (and my JCW).
Gavin, who at the start of the day had a stock MCS, was the baseline MINI; I now hand over to Gavin for his write-up on the day and the experiences with his MINI:
Where to start with upgrades to the car..? I had been thinking about it for a while, I?d done the easy things ? change the runflats for Yokohama AVS100s, upgrade the rear sway bar to a 22mm UUC, but what about the drivetrain..?
I had decided that an intake was going to be the next thing, but which one..? I found one for sale on the mini2.com forums; a BMP with only 5,000 miles on it at a very good price. I read up what I could on intakes, but found the more I read, the more confused I became. There?s a lot of myth about what an intake can do for you, especially when it?s called a Cold Air Intake! My main concerns were would it be too noisy and would it contribute a noticeable increase in power. At the last minute I almost backed out of the transaction to buy the BMP when I read that it added more noise than power, but I?m glad I didn?t.
I waited until the MINI dyno day at Yarrowsport before I installed it, planning to do back to back comparisons to the stock intake. It?s a good job I did as mine was the only stock car there out of 12 (?) to go on the dyno and Yarrow needed something for a baseline. Yarrowsport has a load bearing dyno which is the most accurate kind ? guaranteed to be within 2% at the wheel which is then back calculated to a crank value (I think I?ve got that right). The baseline runs came in at 132 bhp at the wheels which worked out to 162.3 bhp at the crank against a claim from MINI of 163 so the dyno seemed to be running well.
Once the baseline had been done my car was returned to the parking lot and I went to work fitting the BMP intake. It was an easy job; unscrew two screws, unclip the hose to the throttle body, unclip the battery terminal from the stock airbox, remove the top half of the airbox and the stock panel filter, drop in the BMP shield and cone filter and reconnect everything. It took all of amount 10 minutes.
When my turn came around, I wasn?t expecting great gains, but I hoped for something more than just noise. After averaging three runs I was very pleased ? 140.2 at the wheels equating to 169.8 at the crank. 8 bhp from a new filter. Not bad at all. The dyno chart shows a gain of about 3 bhp from 4000 to the peak of 8 bhp at the redline. There?s also a modest increase in torque of about 3-6 ftlb across the midrange.
Having watched some cars get close to (and even on occasion, break) the 200 bhp barrier, I?m sure I?ll be doing some other mods, probably an exhaust next, and I?ll certainly be back to Yarrowsport to test their effectiveness.
The last part of the evaluation was the ride home. At normal highway cruising speeds, the new intake was not noticeably louder than stock, certainly not intrusive. The acceleration in gear from around 3000 rpm seemed a little better by the seat-of-the-pants dyno, but I didn?t need to convince myself ? I had the charts to prove it..!
Thanks to Gavin for that excellent write-up. Hopefully soon we will have graph plots to back up the numbers … and watch out for more about this day, including GBMINIs unexpected results …
M&I / GBMINI 
Gavin, I just didn’t want you to feel left out since people commented on Ian’s entry.
Good job, and good luck with that intake!
🙂
What a nice person … sorry I was not able to “come out and play” at MINI Peabody today!
I think Gavin did an excellent – and unprompted – write-up; I simply asked if he minded he mentioning his BMP experience 🙂
which tire is the best choice to swap for the standard performance runflat tire? I have heard many tires, i just want to know which set has the best grip-