Interesting to note in case someone wants to make comparisons to other figures like in magazines.
The runs were done corrected to JHB altitude. I'm not sure the temperature was corrected and it was a hot day.
Just clicking on the software to change to sea level will increase the power figures by 20%. You lose about 3-4% per 1000ft, and were at 5443ft.
Remember this is wheel HP so the actual motor power (flywheel) will increase again by a value between 15 and 20%. I don't think the gearboxes and drive train are very efficient.
It would be nice to find a value for the drive train losses in the wealth of Mini info out there, but I haven't been successful.
The most important thing is to see the AFR under WOT conditions.
This is why everybody always says you must tune on a rolling road.
Under load the AFR should ideally be between 12.5 and 12.7 throughout the rev range, while little load should ideally be 14.7 This is what people fiddle with on those nice 3D graphs in modern ECU's, much easier than trying to match a needle diameter through the rev range.
You can also then match the timing to prevent detonation.
For us what happens to those little weighted plates in the distributor is pretty much a mystery. So clearly most cars on the day need mixture attention, and those that did well generally had it sorted.
For myself I had dirt in the needle and seat which was just annoying, so all the lower rpm AFR were out, but the final numbers compared within 1hp to those from 18 months and 6000km's ago, so that's cool.
I still have a lean mixture at top end, but will try sort that out with a new needle soon...
All in all it was great fun, and its quite a rush to hear your baby at over 7000rpm and hope it it hangs together!
The runs were done corrected to JHB altitude. I'm not sure the temperature was corrected and it was a hot day.
Just clicking on the software to change to sea level will increase the power figures by 20%. You lose about 3-4% per 1000ft, and were at 5443ft.
Remember this is wheel HP so the actual motor power (flywheel) will increase again by a value between 15 and 20%. I don't think the gearboxes and drive train are very efficient.
It would be nice to find a value for the drive train losses in the wealth of Mini info out there, but I haven't been successful.
The most important thing is to see the AFR under WOT conditions.
This is why everybody always says you must tune on a rolling road.
Under load the AFR should ideally be between 12.5 and 12.7 throughout the rev range, while little load should ideally be 14.7 This is what people fiddle with on those nice 3D graphs in modern ECU's, much easier than trying to match a needle diameter through the rev range.
You can also then match the timing to prevent detonation.
For us what happens to those little weighted plates in the distributor is pretty much a mystery. So clearly most cars on the day need mixture attention, and those that did well generally had it sorted.
For myself I had dirt in the needle and seat which was just annoying, so all the lower rpm AFR were out, but the final numbers compared within 1hp to those from 18 months and 6000km's ago, so that's cool.
I still have a lean mixture at top end, but will try sort that out with a new needle soon...
All in all it was great fun, and its quite a rush to hear your baby at over 7000rpm and hope it it hangs together!
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