[pokeybritches]

I received my dynos back from TTFS, so I did a quick comparison as to the difference in power of an 8-9 psi Z4 3.0i versus a dyno-tuned ESS VT2-500 at various rpm, both with similar power adders (equal length headers, race cats, crossover).

***This is not a scientific comparison***

Don't get caught up in the horsepower numbers. They were done on a Dynocom dynamometer, which is great for tuning but will break your heart if you're used to Dynojet numbers. It reads up to 7% lower as compared to my baseline runs on a Dynojet.

The first % is the difference in power at the specific rpm listed. The second % is the "area under the curve" from 3000 rpm up to the specific rpm listed.

Surprisingly, a basic VF non-M will have 77% of the power of a dyno-tuned ESS VT2-500 Z4M (which was the supremely powerful Z4M for quite some time) up until 6500 rpm. Obviously the M then runs away, because power continues to rise for another 1500 rpm, while the non-M loses mechanical advantage of the lower gearing after the required upshift AND drops down into a lower part of its powerband. But, if you're driving a blown M and get caught with your pants down at 3000 rpm, a non-M that's in the proper gear will walk you up until triple digit speeds. Despite the car having over 500 horsepower, if you're lazy or inattentive, you'll get smoked.

The other thing to note is "torque wins races". If you're running from 3000 rpm to 8000 rpm, 50 extra horsepower at 3000 rpm > 50 horsepower at 8000 rpm (similar to how corner exit speed multiplies on the straights). This is where an ESS twin screw would shine. My G-Power Z4M only peaked 1 horsepower higher than my ESS Z4M back when the ESS car had a stock exhaust, yet the G-Power Z4M put bus lengths on the ESS Z4M due to 50+ horsepower in the midrange. That extra 50 horsepower allowed the G-Power car to be at 7000 rpm when the ESS car was still at 6000 rpm, further increasing the power disparity. It takes a lot of top end to overcome a car that's pulling away from you.