----------
> From: Boog318@aol.com
> To: dakota-truck@buffnet.net
> Subject: Re: DML: Throttle Body Mods, Theory
> Date: Friday, July 17, 1998 10:24 PM
>
> I agree with your theory Mike, but I took "calculus for non math majors"
in
> college so I never had to derive my own equations. Now I wish I did. Oh
> well. Your theory seems correct if your temp and humidity stays
constant.
> What constant values did you use anyway?(too lazy and too far out of
college
> to derive) You might think of putting a thermometer inline with your TB
to
> measure more exact incoming air temps. Id say put a barometer in there
too
> but......:) The thermometer would compensate for engine temps
contributing to
> overall air temperature, thus eliminating a variable. Someone on the DML
had
> a TB thermometer set-up, maybe they will see this and get back to you.
> Boog
Yes, I read about the temperature sensor that someone managed to rig up.
I'm not expecting the weather to change all that much here in New England
over the next two months or so. That really isn't a significant variable, I
don't think. From July to august, we can pretty much count on "hazy, hot
and humid" weather. Ask any Boston meteorologist. They'll tell you they're
sick of repeating that phrase.
When it comes to the constant values you mentioned, I'm assuming you want
to know what I was using for air density, pressure drop across the throttle
body, throttle body length, etc. Well, as it turns out, I didn't have to
decide on a value for any of these, since algebraically, these terms merely
cancel out.
Also note that I am not claiming that a stock throttle body flows 500 CFM
and a modified one will flow 600 CFM. The 500 CFM statement is only a
shot-in-the-dark guess, to be used as an example only. Really, I have no
idea what the flow capacity of the throttle body is. I'm just predicting
that the modified throttle body could flow as much as 22% more air. I could
easily be wrong. That's why I'm doing dragstrip testing. I'm sure that
everyone out there really only wants to know one thing: "If I port out my
throttle body, will the truck run the 1/4 mile faster?" That's what I'm
setting out to prove. My analysis is grossly simplified. If I turn out to
be wrong, well, that's a valuable lesson to me as an engineer.
Like I said, stay tuned...
-Mike Miller
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