[Fot] Fuel Pressure

[John H. Hasty]

Interesting, although we run Weber's, as does Tony, 3 to 3.5 psi works fine on courses without long straights,  but the long straights at VIR, Road Atlanta, Summit Point & Savannah found us having fuel starvation problems near the end of the straight; so we had to up the pressure at the regulator to solve this as well.

-----Original Message-----
From: Fot <fot-bounces at autox.team.net> On Behalf Of Tony Drews via Fot
Sent: Friday, March 10, 2023 2:20 PM
To: fot at autox.team.net
Subject: Re: [Fot] Fuel Pressure

Rod, SU's without grose jets (don't use those) should be fine at 3 psi in my experience.  We were able to run them up to 6 or 7 psi when pushed.

If the regulator works fine for you, no issues.  A problem we ran into years ago was fuel shutting off at the end of long straights (like at Road America - 3 1/2 mile long straights).  Eventually we figured out the regulator was getting deadlocked - the differential between the input and output pressure wasn't enough to keep it cycling so we had to go to a higher pressure fuel pump.  There's actually a regulator in the pump as well and that can fight the downstream one apparently.  If it aint broke, don't fix it - but if you run into issues with fuel starvation after long pulls it's something to look into.

No input on the spark plugs.

Regards, Tony Drews

On 3/10/2023 11:22 AM, Rod Pierce via Fot wrote:
> I recently acquired a fuel pressure checking kit so I decided to check 
> the fuel pressure going into and coming out of the regulator on my 
> Spitfire.   I had about 6 psi going in and 3 psi coming out.  Just as 
> it should be, or at least that is what I have heard.  I have dual SUs.
>
> I'm looking for confirmation or thoughts about the fuel pressure.
>
> Also, what spark plugs to use with my newly rebuilt 1300 with a shaved 
> head and forged pistons.  I'm running 110 octane.  I don't doubt this 
> discussion has been had already so if somebody can direct me to a 
> thread that would be great.
>
> Thanks
>
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