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RE: Fw: dyno running lean

To: "'Chuck Arnold'" <chuck.arnold@oracle.com>,
Subject: RE: Fw: dyno running lean
From: "Mike Munson" <fasttrs@mindspring.com>
Date: Sun, 6 Mar 2005 19:51:09 -0500
Chuck,

One bit of info you left out of the equation; the choke size. In the
SCCA we are limited to a choke size of 28 mm. Sounds like you may be
running a larger choke if you needed 145 mains. When we used mains that
big we were running 34mm chokes f16 e-tubes and 210 airs. 

All these settings are fine tuned depending upon the air density that we
read at the track on any given day.

The Weber books recommend f2 and f11 e-tubes, however we always found
that f16 e-tubes gave us better torque throughout the range and allowed
better fuel emulsification for more hp at top end(6000 and up).

Mike 


What are you using for: 1. Main jets; 2. Air correctors, 3. Venturies?

I have the webers in my hot 6 [40 over forged, 12:1; 300 degree cam].  
At the dyno we used up all my main jets to get it rich -- finally we 
drilled out the 115 mains I had to something like 145.  That now causes 
the car to run to run rich all the time -- right up to 6500 RPM.  I 
started with 160 air correctors, went to 180, and now am at 200 -- still

too rich!.  I have ordered 140 mains and will install them before my 
next track event [Saturday the 18th].  Will let you know the results.
Chuck

rob wrote:

>----- Original Message -----

>
>
>Hello folks  I have just spent some time tunning. I can get a good
Air/fuel
>curve and power all the way up to 5500rpm  At 5500 she is still making
power
>but the A/F is shooting up into the high 15's --16's and i just have to
back
>out   The fuel pressure remains at 4 lbs  the gage has be ckecked
aganst
>another >>   the jet changes will only make me rich at the lower rpm
she'll
>stummble to get cleaned out but still goes lean . We have been all over
the
>board with jetting .With aprox 30 hours  of tunning  We have not been
able to
>get a way from the high A/F  at the higher rpms Drilling the pump jet
helped
>but only put off the  running  lean >>Its a Tr-6   Moss's 40 over
pistons
>stock thre out except for Good parts 1.55 roller rockers  with 40
dcoe's
>11.5 to 1 c/r >>aluminum fly wheel  stock clutch and 4 speed curently
at 155hp
>to the wheels

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