Carrera 3.0 deceleration valve

[Davster75]

I have just bought a 1977 Carrera 3.0 from an enthusiast, who kept it in great condition. He told me that he removed the deceleration valve because he thought it would improve throttle response. I wondered if anyone can confirm this and whether there are any side effects?

Cheers, Dav.

[Longman66]

As far as I know it only controls how fast the engine goes to idle , its was probably removed due to a fault , as long as he blocked the vacuum hoses to it it should be good , not all cars had them iirc , have a look on impact bumpers , lots of info there

[Davster75]

Thanks. I will definitely check out impact bumpers. 👍

[belfry]

Is the car a US import? My German 1977 3.0 did not have a decel valve but my US 1982 911 SC does. I was told that many americans were not familiar with driving a manual gearbox and that they kept stalling the cars so Porsche fitted a decel vale to make this easier for them.

I removed the vacuum hose and plugged it on my SC as I don't like the way that it keeps the revs from dropping, for example when coming up to a roundabout and the decel valve keeps the revs higher than I'd like. My car felt like it was surging slightly when I actually wanted some engine braking. Maybe experiment with both and see what you prefer?

Edited by belfry on Monday 29th April 14:15

[Davster75]

That’s interesting. Mine is a UK car. I am really happy with the way that it drives, so will probably only investigate if things change. Good to know that it is fine with or without the valve. Thanks for posting 👍