[dave67]

Why do most efi fords have such an extreme dashpot?

When I let off the gas pedal, I like my engine to get to the desired idle rpm quickly. (~670 rpm sounds good even with a decent cam). But good ol factory efi takes forever. I bet on most vehicles if you snap the throttle sitting still it will take 3 or more seconds to get back to desired rpm. And what's worse if your deceling and pulling into a parking lot or something, idle will hang around 900 rpm or so till your almost completely stopped. And if your a hot rodder, you wanna hear your lumpy cam, not a sticking idle.

I understand this is to prevent stalling, but it seems overboard to me. Back in my carb days when you snapped the throttle shut, there was no dashpot, and I don't recall any stalling issues.

Now a little dashpot is good, but I don't think it should be anything like the stock settings. In fact this is part of the reason I got interested in tuning.

Anybody else agree with me on this?

[decipha]

on a carb theres a closed throttle return rate that gives you dashpot

dashpot also reduces emissions

if you have a large enough cam you need about as much dashpot as you can get returning to a stable idle

I think 3 seconds is fine and thats what I shoot for, IMO it doesnt bother me and i like it

the minimum dashpot clip is to prevent bucking on slow creeps

[dave67]

on a carb theres a closed throttle return rate that gives you dashpot

Agreed. A lot of factory carbs had a little canister with a diaphragm and spring to slow the linkage right before idle. However aftermarket carbs don't have this and I don't know of many people to add it. The throttle blades close just as quick as you could get your foot off the gas.

if you have a large enough cam you need about as much dashpot as you can get returning to a stable idle

What is the reason this is required? Does closing the air off too quick cause a temporary rich spike or something and the eec can't adjust quick enough? Or is it just some mechanical thing like the engine is slowing down so quickly that it wants to keep slowing down?

the minimum dashpot clip is to prevent bucking on slow creeps

What? You mean you don't like the classic "slowing down in a high gear and the car start lurching back and forth rapidly, u-joints clanging, motor mounts breaking, possible whiplash and your girlfriend looking at you like you can't drive."

That's just cool in my book. Haha. Jk

[decipha]

ahh, yea the lost appeal of hot rods

big cams have a lot of overlap, at low airflow the mix is often diluted with exhaust gases (mechanical egr due to the cam) and it doesnt help that they draw very little vac so in those cases its difficult to get good combustion, in order to prevent the engine from clunking out you have to give it quite a bit of air to make it decel slower and help it stabilize no different than backing off the throttle slowly rather than letting it go