My thanks again to Gavin for his write-up yesterday; now here is the day from my perspective …
First, lots of MINIs to meet again, including Steves fabulously clean Electric Blue MCS – I first noticed his spotless carpets when I installed a MINI circuit for him, then later saw his engine bay.
But back to the dyno. GBMINI was first tested about 3/4 hour after I arrived … loaded on to the dyno and set up and tested by Yarrow:
The noise during the run is horrifying, with fans to keep the engine somewhat cool, the dyno and of course the noise of the engine being rev’ed up to its max! I recorded and uploaded the run – here is the audio only (you will hear Gavin comment on the low performance at the end!):
I have also uploaded a video of the run but it is over 20MB and not much more interesting than the audio!
The first run was surprisingly low at only 185hp – with JCW claiming 200! Yarrow decided “heat soak” from the drive down might be an issue, and GBMINI was left to cool with a fan blowing on it for a few hours.
Meantime other MINIs ran, with results from 170hp to 192hp depending on aftermarket parts – it was clear that without a reprogram, the pulley and/or exhaust alone do not perform so well. Check out the MINI2 thread for more discussions of the results.
After the other runs, GBMINI was given another chance and showed an improvement to 191hp – still shy of the claimed 200hp but a match for MINIs with aftermarket pulley, exhaust and engine reprogram. For fun, Yarrow and the other dyno guys did another run after “super cooling” the engine intercooler from a cylinder of compressed air (empty of nitrous) – this gave a more than 5% increase to almost 202hp!
So what have we learned:
Testing lots of MINIs together is great fun!
Yarrows dyno gives representative results for a stock MCS and of course reasonable comparitive results for MINIs tested on the same equipment and same day.
Dyno runs make a lot of noise!
Gavins BMP intake gave a reasonable 3-6 increase.
GBMINI showed results no better than a good aftermarket package, and significantly down on claimed JCW figures.
Super-cooling the air into the engine is a big help to maximum performance.
M&I / GBMINI 
Don’t get to down on the lower than expected numbers. Remember that the dyno gives you horsepower at the wheels, and usually the manufacturer specs horsepower at the crank shaft. That’s the difference. Besides that, 191HP is nothing to sneeze at! You still have me beat by 84…
Thanks … I am not much bothered by the numbers because I know how GBMINI drives 😉
Looks like you had fun that day. I wish I knew more MINI folks.
I know it would be nice to have more pony’s but for the cost of the JCW’s package I expected a lot more.
The movie was cool thanks Ian.
BTW…my wife did order the A4t Quattro with the Premium & the Ultra Sport package this weekend. That is if the dealer will come to her price. We noted the HP as you suggested but it’s fine for her.
…RB
I imagine the claimed 200BHP from JCW is “at the crankshaft.” JCW undoubtedly uses and engine test bench w/ dyno and gets their figures from there. Driveline “slop” and friction rob 10-15% (sometimes more) of you power “at the crank.”
Good numbers!
THose numbers are actually better than what JCW claims. Your getting about 214 at the crank.
Any chance you can explain that further – all these wheel/crank/hp/torque/rpm figures get me confused easily 😉
He’s talking about drivetrain loss.
The number represented by a chassis dyno is power at the wheels.
To ‘estimate’ crank horsepower, you do this simple equation:
BHP – driveline loss% = WHP
Generally, FWD cars get between 12 and 18% driveline loss (I use 15% as a standard)
So, let’s say you made 150whp. divide 150 by .85 (15% driveline loss) and you get 176.47bhp
Pretty simple, however all these numbers are estimates as there is no standard DEFINED driveline loss. What I do is divide by 12, 15 and 18%. Generally, it’s somewhere between there. I use dynos to see if the car is running right more than anything.