This is normal. If you increase the length of your post-throttle intake, you increase the amount of intake charge which must be consumed before the tract falls into vacuum and idle conditions. So when the throttle snaps closed it takes a moment to affect the engine speed.
I've assumed that your throttle is now before the S/C, whereas before it would have been at the manifold (in 4A-G) or at the carburettor (4A-C). Correct me if I'm wrong.
Fri, 26 March 2004 05:53
