Breather setup on 3.5 EFI RV8

[Big Hyndy]

Just changing my SU's for a flapper system today and its all fitted minus the loom but what im needing to know is what are the 2 breathers on the underside of the plenum at the throttle butterfly? Can anyone help me out or help me or hook me up with a link to a diagram of the setup.

[paul c]

From memory it sounds like you are talking about the two connections to the cooling system

[ChrisJC]

Yes indeed.
One should go to a stub pipe on the inlet manifold near the temperature sensors at the front.
The other one goes to another stub pipe, this time I think it's on one of the pipes that runs from the water pump rearwards in the valley.

Chris.

[K4000JB]

In my view they are better left not connected unless you live somewhere very cold.
The hot water warms the inlet charge reduces power, just my opinion of course

[Big Hyndy]

K4000JB thats what ive done bud, the car is all done up and running and it is a great improvement on the SU's. I had it out for a good 30min on a test drive with no issues but since driving it home it has developed a miss that seems to be getting worse but ive not had a chance to look at it, going to change the plugs etc. I can live with some teething problems im just glad it fired up and ran on first attempt.

Next question, it ticks over pretty high, is there a way of adjusting this or is it a case of a sticky stepper?

[DaveEFI]

If it's a flapper, fast idle is via an extra air valve which has no clever control - it simply works on engine temperature (plus an electric shunt coil). The base idle speed is set by a screw on top of the plenum. This controls a throttle bypass bleed.

[K4000JB]

Maybe worth checking for an air leak in my opinion, ramon albon(sorry spelling) On here has a great site for the flapper system on the sd1 iirc

[Big Hyndy]

Cheers guy much appreciated I will let you's know how I get on! Is there a link to Ramons page or a name for his site?

[K4000JB]

Try this
http://www.vintagemodelairplane.com/