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Originally Posted by VipinLJ
Sweet baby Jesus. 252 whp and 270+ wtq is crazy. Not completely surprising though since BMW does have a tendency to underrate their engines.
I haven't been able to dyno my car since the ones near me (upto 1.5hrs away) are all 2WD dynos. I've used virtual dyno and my car's baseline (map 0 on JB4) was 225/246 and with map 6 (without EWG connector), it was 285/310. Runs logged on the same day, just a few minutes apart. With the EWG connector and updated map 6 (on a different day), it was 299/327 (all numbers are whp/wtq). Again, this was using virtual dyno and not an actual Dyno (though VD is supposedly pretty damn accurate if logged correctly and I did manage to get the tyre diameters, weight and gearing along with temperatures for the respective days online to set it up to be as close to an actual dyno run as possible). Smoothing was also set at a higher number since lower smoothing showed higher numbers and I don't believe I've hit 300whp on stage 1. I don't doubt those numbers much since it's significantly faster than my stock SQ5 (354bhp/369tq) and even my stock A7 (333bhp/325tq) even though they're heavier cars.
Fuel used is 93 octane for stock run and roughly E25 (3.5gallons E85 and rest 93 octane for a full tank) for the map 6 runs. No weight reduction. Those runs were done on a full tank, usually with atleast one passenger (excluding driver) in the car.
I had these numbers saved in my notepad but can't find dyno pics since it was on an old phone. I might have the logs I used to calculate those numbers. If not, I'll have to do one later when it is warm and post updated results.
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You really can’t compare VD vs an actual Dyno, hell, comparing between different Dynos is bad enough as is. Only thing one can really compare directly are the changes in power on the same car on the same dyno (or stretch of road for VD in as similar conditions as one can manage)
At the end of the day the best best comparison is something like 20-80mph or maybe 40-100mph since it largely eliminates traction and “skill” from the equation.
A BUNCH of stuff affects whp on a dyno.
The same car on a dyno with different set of wheels/tire which are same diameter but different weight can read 20hp different (this isn’t “fake” it’s real, you need to expend more energy to spin up the heavier wheel/tire combo so you ARE putting “less” power to the road).
If you run the dyno at 200kph vs 100kph you’ll also have an appreciable difference in whp holding EVERYTHING else constant. It’s actually a bit ironic that the “backed out” engine power figures are slightly more “accurate” IF AND ONLY IF the calculation is done properly (which is effectively impossible in an automatic transmission) which most new dynos are capable of doing but still requires the operator to do it properly which is surprisingly rare (you’re supposed to clutch in on the coast down and not leave it in gear in a manual, in an auto there really isn’t a “good” option, before anyone’s asks, no shifting to neutral is not the same thing).