[Fot] FW: False or skewed EGT readings in a TR4

[Jim Gray]

  _____

From: Jim Gray [mailto:toodamnfunky at comcast.net]
Sent: Sunday, October 25, 2009 12:59 PM
To: Friends of triumph (fot at autox.team.net)
Subject: False or skewed EGT readings in a TR4



I think Im getting false EGT readings due to airflow over the #1 header
tube.

The probes are about 1-1/4 from the flange in #s 1 & 4 tubes.

Im using Mikuni HSR cabs. When jetting, needle settings and pilot air screw
settings

are equal front to rear I get equal EGT front to rear while static. As soon
as I drive the car

or turn on the electric fan then my front EGT reading drops. Thats why I
believe its air

flow over the exhaust and not jetting. By the way, I dont use a fan shroud,
with the Griffin

radiator I dont need it. I fabricated a small shroud for the front tube,

it only had a mild effect.

At wide open my AFR reads 14.6  14.7   In order to keep the rear temps from
going over

1,250  1,300 I have to run in my rear pilot air screw to within = - > turn
from bottom

it really wants to be 1 to 1.5 turns out.

Another bothersome thing is I am using the fattest jet needles made for
those carbs and

I race at 5,000 feet( Colorado). Before I went to the larger

jet needles my temps were 1,300 -1,400 unless I ran the pilot air screw in
to within < - =

from bottom. Im going to the Topeka race next year which is 800 ft above
sea level

so I need to get it worked out by then.

I really dont know what my EGTs are at wide open or at least I dont trust
the readings Im getting.

Does anyone else have this problem and if so how are you dealing with it?





Oops sent to soon,

Thanks for any input,



Jim G