throttle response?

[crashmy911]

I have a 1978sc. Is it normal for you to rev the engine and the throttle to hang up some before returning to idle. Also inbetween shifts is it normal for the revs to fall slowly? Is there a way to get them to drop off more like a modern car or is this something that I have to live with? thanks Jim this is a cis fuel injected system.

[Paulporsche]

That is normal/correct. You can eliminate this by plugging the top vacuum line to your decel valve, or adjust it by turning the adjustment on the top of the valve.

[jwetering]

Originally posted by Paulporsche
That is normal/correct. You can eliminate this by plugging the top vacuum line to your decel valve, or adjust it by turning the adjustment on the top of the valve.

Hey that's right...I remember bypassing my decel valve back when I first got my car. Seems like a long time ago but it has only been nine years. Man!

[FrayAdjacent911]

Doesn't a heavy flywheel affect this, also?

[pieterk]

Originally posted by Paulporsche
You can eliminate this by plugging the top vacuum line to your decel valve, or adjust it by turning the adjustment on the top of the valve.

Interesting. I always thought that flywheel weight changes would have the biggest influence. How much of a change will this yield and are there any risks or downsides to it? How does it compare to lightening the flywheel?

This is something I've been wondering about. Several of the 911s I've driven had what I think of as somewhat sluggish throttle response and I'd be interested in knowing how that can be addressed without building a really expensive, really high strung race engine.

[RoninLB]

deceleration valves get old and may need attention eventually. I plugged it when I ran CIS. It's a smog contraption.

[stlrj]

Several of the 911s I've driven had what I think of as somewhat sluggish throttle response and I'd be interested in knowing how that can be addressed

It's very easy to kill the throttle response on a DME 3.2 engine. All you have to do is have the mixture set too rich, beyond the range the 02 sensor can compensate.

To make things worse, the mixture control on the AFM is impossible to access and highly inadequate when compared to CIS.

Joe

[crashmy911]

I don't have to worry about smog, So how do I eliminate it? Does any one have any pictures of what I have to do?

[RoninLB]

Originally posted by crashmy911
I don't have to worry about smog,

can you install pistons, cams, & carbs ?

[stlrj]

Do you really want to devalue your 911 with these mods?

Joe

[RoninLB]

"devalue" is a subjective opinion.

One big hp pelican member wanted to buy my car if I ever sell it. Another P shop owner also wants 1st crack at it.

Either you like personalized 911's or you don't. Everybody's correct.