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Re: your mail

To: Shane Ingate <madmax_xx@hotmail.com>
Subject: Re: your mail
From: "Robert M. Lang" <lang@isis.mit.edu>
Date: Tue, 4 Dec 2001 12:14:58 -0500 (EST)
Hi,

Just for the record, you do not need a cam and lots of compression to make
Webers work. The beauty of DCOE40's is that they can be tuned nearly
infinitely. So, if you're closer to stock you use one setup, if you're
going radical you can tune accordingly.

Don't ever buy the argument that Weber DCOE 40's are "too much carb" for a
stock engine. It's just not true.

Another very important aspect of going to Webers is that if you are
starting from scratch with them, you need to make sure the motor is in
perfect tune first, otherwise, you'll get false positive readings when you
change stuff... and if you eventually realize that the motor needs
attention, you'll likely be starting over again once you fix things.
Believe me, there are plenty of people that give up on DCOE40's due to
problems encountered because of a motor in a poor state of tune.

Most people conclude that the carbs are too big when they get "reversion"
(gas spitting back out), falsely assuming that the motor is rejecting the
fuel. This is usually due to factors like choke tubes that are too big
(causing air velocity to be too low to properly aqtomize the fuel/air) or
improper air correctors - factors that effect the way the fuel/air mixture
occurs. Or they tune the idle jets way too rich to get the car to idle
(usually this is done incorrectly, BTW).

Now, to tune for more power, you need to get the car on a dyno and check
things out and then change the jetting according to what you see. This
means you have to read the plugs, get an exhaust gas analysis, check the
exhaust gas temperature etc.

And to really take advantage of the Webers, you do need to pay attention
to the way the exhaust gasses are expelled from the motor. This is really
important!!!

By way of example, a stock TR6 with 2 Z.S.'s checks in at 104 HP. With
Weber DCOE40's, port matching and a tuned exhaust, you can get over 120
HP. If you diddle with the cam timing a bit and dump the crank driven fan,
that number can go over 130 HP. 

If you "do it wrong", you can actually take power away in certain
circumstances.

So, having the Webers by themselves is not necessarily a performance
enhancement, but because of the range of adjustments possible with
DCOE40's you can tune to any requirements. But you also need to know what
you are doing or you need access to someone that knows what they are doing
if you go this route.

Thanks for your time.
rml
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