BTW, Here is one piece of advice when you experience a= power loss at high throttle. All engine systems are under maximum str= ess at full power and it is often the case that if you ask a bit less of the= m, they might work better. I understand the urge to firewall the thro= ttle when power sags at takeoff but TRY reducing throttle momentarily to see= if you get better engine performance. This has saved me from at least= three aircraft accidents. When that clogged inlet filter caused a po= wer sag in the RV-8, backing off on the throttle lowered the fuel demand of t= he engine and the fuel pressure recovered enough to let the engine run norma= lly at reduced throttle. Same thing applies to other situations. &nbs= p; When my Rotax powered Twinstar started loosing power on climb out I reduc= ed throttle and the engine recovered. Piston seizure was the problem b= ut reducing throttle let the piston cool a bit and total seizure was avoided= . I replaced rings & scuffed pistons after nursing it 80 miles to= home.

Sent from my iPad

On Aug 31, 2011, at 9:50 AM, "Al Wick" <alwick@juno.com> wrote:

<if there is not a method to bleed down the rail the risk of vapor l= ock=20 exists

So you are saying every car built since 1990 has this "vapor lock" prob= lem?=20 We would see thousands of cars unable to start at every desert truck stop. T= his=20 concern for fuel rail is a myth.

Vapor lock is not a myth. It occurs at the fuel pump inlet. Very import= ant=20 to minimize pressure drop there. You can actually measure how far your desig= n is=20 from vapor lock. You don't have to guess.

The bleed helps if you totally blew the plumbing from tank to fuel= =20 pump. But much better to fix that plumbing error.

-al wick

----- Original Message -----

From:=20 Dave=20

To: Rotary motors in aircr= aft

Sent: Tuesday, August 30, 2011 9:14= =20 PM

Subject: [FlyRotary] Re: CG Product= s=20 Intake Manifold

HOWEVER..... if there is not a method to bleed down the rai= l=20 the risk of vapor lock exists, as the rail heats, the fuel boils, and the=20= vapor gets trapped in the line.

If you DO put the regulator upstrea= m of=20 the rail, its imperative to be able to be able to flow fuel past the injec= tors=20 and to a return line to avoid any possibility of vapor lock. The easiest w= ay=20 is simply to put the regulator downstream of the rail and injectors, but=20= again.. this arrangement is more about preventing vapor lock, not ensuring= =20 adequate pressure.

Chris and I were forced into the upstream appro= ach=20 by the Mistral fuel rail configuration, and I didn't want to mess with=20 drilling out the pinhole and then running a regulator downstream - Mistral= was=20 hard enough to get the intake from, and we didn't expect getting a replace= ment=20 part if we had an OOOPS would have been easy. As others have now found out= ,=20 Mistral isn't selling parts.

So... anyways.. just wanted to clarif= y=20 previous post. 1) can regulate pressure anywhere in the fuel circuit= =20 between pumps and injectors. 2) Must provide for mechanism to flow fuel pa= st=20 injectors to prevent vapor lock.

Dave

On 8/30/2011 11:06 PM,= =20 Dave wrote:=20
No... at the= flows=20 and pressures we are using (and barring any major obstructions between t= he=20 regulator and the injectors), the regulator can be anywhere in the circu= it=20 and adequately regulate the pressure.

On Chris Barber's install, I= =20 purchased the Mistral intake for use on his engine. The fuel rail was a d= ead=20 end tube with a pinhole on the end. Presumably the pinhole was to preven= t=20 vapor lock in the fuel rail. The regulator HAD to be upstream of the=20 injectors when using the intake. We had stable fuel pressures and no=20 problems getting fuel to the engine.

We had return lines from th= e=20 pinhole end of the rail, as well as from the pressure regulator, that fe= d=20 back to the sump tank. Since there were not check valves running from th= e=20 wings to the sump, there was no chance of pressurizing the sump.=20

Dave

On 8/30/2011 10:30 PM, CozyGirrrl@aol.com wrote:=20

Ed, I must have mispoke to give this impression, I thought the=20= pressure reg HAD TO be last in line to maintain pressure in the fuel=20= rail?

Chrissi=20 & Randi
www.CozyGirrrl.com
C= G Products, Custom=20 Aircraft Hardware
Chairwomen, Sun-N-Fun Engine Workshop

In a message dated 8/30/2011 10:13:53 P.M. Central Daylight Time,= e= anderson@carolina.rr.com writes:

If the pressure regul= ator is place before=20 the injectors then there is less fresh fuel flowing through the=20 rails.

= --Apple-Mail-73--646760266--