Post trackday thoughts:
On Thursday, Oldtimer and myself travelled down to Castle Combe for the annual 928 trackday. On the way down the springless throttle was a pleasure to use. Light on the foot and it seemed very responsive. Very useful in those convoy situations where you get separated by a numpty that wants to get in the middle and then have to accelerate quickly to catch up the gap.
On track at CC there were again no issues and there was definitely a better feel when adjusting the car on the throttle. In the afternoon I refitted the spring so that I could make a comparison of with and without. Immediately the throttle felt stiff and comparatively unresponsive. However, on track, it made no difference in how fast I went round. Not that there was any timing of course [
]. On the long journey home the throttle definitely made harder work for me and after 2 hours of motorway cruising, some numbness in my right foot was creeping in (which didn't happen on the journey down).
Now the science bit. Melv's cup car, which of course has a plastic inlet, was on hand for a comparison. The pictures below show the difference between his throttle arrangement and mine. Melv's has a single beefier main spring whereas mine has a more delicate main spring with more turns and a second spring. So my guess is that later cars did away with the return spring when the main throttle position spring was beefed up? Also, I found that the throttle pedal on Melv's car was softer than mine when it has the return spring fitted but was stiffer than my pedal with the return spring removed. i.e. pedal feel on Melv's car is somewhere in between.
Pic of throttle arrangement on Melv's cup car (no return spring as standard on his car)
Pic of throttle arrangement on my early car (with return spring removed).
