I thought the same TBH. Not sure where the problem lies, or even if there is a problem. The exhaust could be restrictive as it was originally designed for a 2l twin cam. Just because it's loud doesn't mean it's free-flowing!! I do want to do something about the exhaust anyway and was planning on fitting something bigger and quieter. I'll try and get another power run with a new exhaust before mapping the blower, as I suspect both jobs will get done at the same time.
Comparing wheel HP figures from different RRs is a mistake though I think. Far too many variables for it to make any sense whatsoever. The only truly accurate way is an engine dyno of course.
It would have been nice if we'd had the time to muck about with a few things like making sure the air filter/inlet piping wasn't causing problems but after a late start and the problem with the valve on the wheel we where running late. Maybe next time.....
The Zetec engined Westfield I took there a month or two back made 168bhp, which was pretty much spot-on where it should be for the spec of the motor, hence my feeling that these figures are as accurate as they are likely to get using rollers. The purpose was mapping though - the car now drives really nicely (much better than it did on the Motronic by the way) which is all that matters for me really. Power figures are much abused IMO, but then having achieved such a poor one, I'm bound to say that, aren't I
Maybe after a few more miles it'll loosen up a bit more too.
Anyway, I'll come back with some more once I get around to putting the blower on.