An R55 is a Clubman.

 

I have discovered a characteristic of the SB that I personally don't like, but others may not be so bothered by it (given the posts here, I'd guess I am certainly in the minority--of one, perhaps.)
Without the help of diagrams, let me characterize the stock throttle response (TR) map as being more convex: it rises slowly, then quickly to WOT. The TR map for the SB rises quickly at first then tapers off to WOT. The input range and the output range are identical, it's just the shape of the response curve that differs.
The steeper SB curve is responsible for the feeling of "quicker acceleration" but there is a downside for me. And that's what happens when you lift off the accelerator to shift gears. The top part of the SB response curve produces a slower response, and hence the engine remains at higher revs for slightly longer after pedal lift compared to the OEM throttle response. In fast-shifting situations, like drag racing, this can lead to over-revving and clutch slip when shifting up through the gears.
I found it requires quite an "adaptation" to get used to the new response curve of the SB. And more so thanks to the lift-off response rather than the push-down response (which I whole-heartedly love!)

 

Gen 2 Turbo engine.....

I thought I saw something over at the gen2, SB, can't find it.... or mistaken

 

Interesting.... The gen 1 is linear, or seems so. I found shifting up or down easier right from the get go..... could be age. Lift off is just as quick... matching gears is easier, but I've had 3 years with it, so.... a side by side would the true tell.

 

My experience and comment is speculative--as the TR maps published on the SB website are obviously only there to suggest TR curves, and are not actual maps for specific vehicles. And what the stock TR curve looks like is also unknown (to me.) What I am suggesting is that *relative to each other* the curves must have the shapes I proposed.
The issue of how the car responds to throttle lift off is also quite complicated. It's quite possible that the response of the engine to throttle lift is not linear or symmetric with how it responds to throttle push. Since the TR curve of the accelerator pedal is *but one* input to the system, I cannot prove that what I am experiencing is due solely to the DB TR map, but it must be influenced by it since my car behaves differently with the SB engaged verses when it is disabled. These type of systems are highly non-linear. Even if each component is linear--which they may not be--any error in any component (which there could be given that many are electro-mechanical devices) could produce non-linearities in the system.
btw, I'm not criticizing the SB, I'm simply pointing out a characteristic of it --as it manifests in my car--that I have analyzed and of which I have suggested a possible cause.

What I would really like is a SB TR map that is SB for throttle push, but OEM for throttle lift. This would be relatively easy to program, but might reek havoc in reality. Of course, electrons move way faster than feet, or throttle butterflies, or pistons even.

 

This is truth. I broke mine testing the SB at the Dragon (courtesy of Way - THANKS!).

The base of my pedal now has a beautiful screw holding it so it doesn't come loose on the track (which would suck...)

FWIW - I definitely "get" what this thing does now... it's kinda fun and addictive... but after driving with it on Hellbender for half an hour while watching the Throttle Position sensor values on the ScanGauge, it was apparent what it was doing... making the throttle much more "binary"... and I like the amount of modulation I have now... doesn't "feel" as fast... but I had more throttle control with thing turned off. I know some people love it. For me, it would be a gimmick. And I already have too many of those on the car.

 

More interesting..... there seems to be some difference from gen 1 - gen 2 SB other than adjustability. Reading the scanner, TPS, looks almost the same as the cable control on my other blower car........

 

You know Paul, I don't know why I haven't been doing my own monitoring. I have a Scangage as well. Mine is used primarily for water temps, but monitoring the TP sensor readings would be an interesting thing to watch for on my morning and afternoon commutes to anne from work.

 

What's the difference between the stock "Sport" button and using a Sprint Booster type controller? Nobody ever mentions the Sport button in these discussions.