Improved throttle response

[NicBowman]

Hi All, many people complain about the S's throttle response at low revs. I noticed that the throttle butterfly opeing is controlled by a cam, and opens very slowly initially and very quickly over the last bit. This would make the low throttle response slow, okay for Granada's? This would be fairly easy to change, a revised cam profile with linear opening. Has anyone done this, or know any more?

Nic

[GreenV8S]

At low rpm you get something like 80% of the torque in the first 20% of the throttle rotation. It is very sensitive to small throttle openings at low rpm. The snail cam is designed to make the throttle response more or less proportional to throttle pedal position. If you replace it with a plain pulley I suspect you would find it harder to control the revs accurately, for example when pulling away from standstill. Changing the throttle pulley wouldn't make much difference to the throttle response when you have the throttle wide open so there's probably no advantage.

[S3Swiss]

The non-linear opening of the throttle helps with 'around town driving'. Used to have a rally car with twin Webber carbs which we experimented on with various set-ups, mostly learning what we didn't like!
A fast and direct throttle response is a nightmare to use when creeping along in traffic - once the flywheel has momentum (from accidentally pressing too hard), it takes a few moments to lose it, by which time you've backed off the throttle and the revs die below stall speed! Makes for interesting driving on bumpy roads as well, as every pothole causes weight of foot resting on pedal to increase revs! If you do go for a more 'direct' linkage - my advice is to increase the return spring pressure as well. This helps reduce the above unwanted side-effects!

[mycroft]

I have read an article on this ,someone who has made a new cam to altar the throttle characteristics.
I tried to have a look on here but can`t get into the search section at the moment, but i think it might have been an old sprint, I Will have look through some back issues if i get a chance later.

[foxy600]

There is a replacement throttle linkage available, I'm having one fitted to my S2 at the moment, try Guglielmi Motorsport 01327 878425