[Land-speed] Carb Lean Out Help Needed.

[gary_ellen at q.com]

His air scoop could be pressurizing his float bowl through the vent.

Gary

----- Original Message -----
From: "Larry Mayfield" <drmayf at mayfco.com>
To: land-speed at autox.team.net
Sent: Sunday, February 9, 2014 5:25:08 PM
Subject: [Land-speed] Carb Lean Out Help Needed.

Not for me, of course, I run EFI. But one of my associates in the Sunbeam
Tiger world races his car on circuit tracks and is having a lean out issue.
He runs a Holley carb not by choice but by rules. B He has a small hood scoop
whichis forward facing and is about 8 squares inches in opening size. And it
is sealed to the carb or the carb is in a box, so to speak. B This is on a
Ford 289 motor. B It B is built. B He uses an Innovate AFR wide Band system
to
monitor his fueling. B He says that when he launches in low that AFR is low
12, maybe 12.0 or so. Second, it starts to lean out, ditto third at around
140 mph, it is running more than a full point leaner, a tad more than 13.0.
So he is either getting more air or less fuel, but he does say that his fuel
pressure is rock solid. B I asked him about the appropriate size of the power
valve and also if he might have a vacuum leak that manifests under load. He
said he didn't think so. B 

So, I am asking, on his behalf, the folk who run a carb on the salt or EM
and no other power adders, if they have experienced anything like this, and
if so, did you find a solution that I might pass along to him. B Or any
additional trouble shooting ideas. He is not a noob at this so I am sure he
has checked all the normal rational things. B 

Any help out there?

mayf

_________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
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