Subject: [Fot] High Altitude racing

From: "Robert Johns" <[email-masked]>
Date: Wed, 30 Jan 2013 16:59:02 -0500

Hi guys,
Tyler wonders who has raced a Triumph  at high altitude?  I will offer this
submission.  In the fall of 1956 I was racing what ever SCCA was running that
I could reach.  A hill climb came up to be run at Los Alamos.  I went up on
Saturday from Roswell, where I was stationed, and spent the afternoon tuning
for the altitude. Come Sunday morning, I lined up and went off.  I came back
down after the run to line up again, for another try.  The starter came over
and said, Your time is some much better than others, why take another run,
wait and see what the later times are.   It ended up that I was second fastest
run of the day.  The only car faster was a 120 or 140 Jaguar from Los Alamos.
There was a C3 or C4 Cunningham there, but he was way too rich.  From memory,(
that is a long time ago)  Los Alamos is 10,00 feet and tuning for that
altitude made the big difference.
Robert Johns
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From: Bud R <[email-masked]>
Date: Wed, 30 Jan 2013 16:58:18 -0700

In theory if you're running a constant depression carb like a ZS then  
altitude should not make a difference since the less dense air should  
pull less fuel. In practice many cars that have come from lower  
altitudes have found they run too rich at Colorado altitudes (5280  
ft.) and above. Usually leaning the mixture helps.

If you run Weber carbs or something similar then you have to do  
correct jets and venturies to get it right. Yes it makes a big  
difference since we have about 5psi less air pressure (inches of  
mercury) than at sea level. So a supercharger (with 5 psi of boost) in  
Denver would just about make up for how my TR6 ran at Galveston TX, or  
Jekyll Island where I was in heaven with the kick in the pants the  
accelerator gave me at those sea level venues.

Bud Rolofson

71TR6 CC57365 (Good 6)
71 Spitfire MK IV Race Car #3
66TR4A CTC57529 (The Project)
71F-250 Camper Special (Triumph Support Vehicle)
Z-50A Hardly Davidson 1977 Honda Mini-Trail Bike (Triumph Pit Bike)

On Jan 30, 2013, at 2:59 PM, Robert Johns wrote:

> but he was way too rich.  From memory,(