The potential loss of the Harrop SC from the US market has me forlorn and considering other options. I've put together these charts to compare the boost in HP and torque that each unit has demonstrated with dyno data. I know this comparison is inherently flawed so save your rants, but it gives a ballpark for comparison. I initially included the Active Autowerkes SC on this list (Gen 2, level 2), but the only data I could find was at 93 octane and it was the worst performer of the bunch (IMO) so I dropped it.
All three SC dynos were done with 91 octane, which is what I have available locally. All 3 were DCT but gear was not always described. The VF620 is stock exhaust/cats while the Harrop and ESS G1 were with test pipes. So not exactly apples to apples but we use the data we have. The Harrop is a BPM tune.
Obviously HP and torque data will vary dyno to dyno. This variability is somewhat assuaged by analyzing the difference between the SC and base model, rather than raw numbers.
From a HP perspective, the ESS G1 and Harrop compare favorably from 4500 RPM and onward. The Harrop has a slight advantage early on. The VF620 lags behind the group, but it's with regular CATS instead of test pipes.
Again, torque comparisons show the ESS G1 lining up well with the Harrop at 4500 RPM. The early noise in the torque data on the harrop is due to the dyno of the base car showing a steep drop off of torque in that vehicle in low RPMs and not supercharged.
If anyone has VF620 dyno data at 91 octane and test pipes, I'd love to see it. For now, I'm treading water to hear whether Harrop will offer one last US production run - but considering the ESS G1.
Cheers -