The old slide valves of the old Lucas/Webber/Marelli competition
injectors of the sixties and seventies did this, but that would require
a complete re-engineering (and certification) process.
Shaun.Hendricks@bergenbrunswig.com wrote:
>
> Been watching things for a bit on the whole TB mod issue. DMLer X vs DMLer
> Y vs DMLer Z vs Standard Production... etc. It seems to me that you can only
> do so much before you've hit the wall. No matter what, with each different
> approach you're going to get different preformance benefits. It's a great
> thing, but what about a single TB mod to fit variable needs.
> An idea for the truely experimental ones of you, take some lessons from jet
> aircraft. You need a variable geometry TB follower plate. Essentially a TB
> is just an air intake orifice and the butterfly valves control the amount of
> air allowed through the orifice. The problem with "enlarging" the orifice too
> big is a loss of torque because the air velocity into the cumbustion chamber
> is decreased. The problem with them being too small is that a horsepower loss
> happens due to a smaller amount of fuel/air being available. This is just
> general talk, I don't need a full technical detail made to me, I'm in
> conceptual mode.
> You can't have a variable orifice because the butterfly valves can't adjust
> sideways. An iris valve isn't as fast as butterfly valves for response so
> they're out. In order to keep the butterfly valves and a large orifice TB,
> you need to have a post TB adjustment plate, something that can "narrow down"
> or "enlarge" the opening as necessary for different sections of the power
> curve. The idea is to take the design from a jet which controls it's thrust
> by a set of vanes that open and close to change the geometry of the thrust
> (it's called a thrust cone). A small set of these just under the TB, mounted
> on a separate plate (so it becomes a mod unto itself) with a solenoid or cable
> controller could adjust the airflow for high velocity at the low end and as
> more horsepower is needed, open to allow maximum air flow.
> Obviously this is not a simple toy, but it is possible. For you "gotta
> squeeze every last ounce of power" guru's out there, it might be a cool item,
> but me personally, if I modded for horsepower and then went to tow, it would
> be a great thing just to engage with a pull knob. Have a matching buddy in an
> expanded exhaust system to provide the needed backpressure for max torque and
> you have a great combo for developing torque on demand... It would be
> interesting to see if something like this could be made, and just how
> effective it would be.
>
> Shaun H.
-- Shadowcatcher Imagery http://members.tripod.com/~shadowcatcherimagery/index.htm
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