I'm pretty sure those reed valves are used as a check valve against air
or air/fuel travelling backwards through the intake manifold and out the
TB bores. They use tham a lot on 2 strokes like dirt bikes,
snowmobiles, etc. I wonder if they would serve any value on a 200-400
cid 4 stroke V-8?
Cale Bargen
Bob King wrote:
>
> I think some Yamaha motorcycles had what they called a "reed valve" that
> functioned in a similar manner to what you describe to give more torque down
> low and still open up big for horsepower at the high end. I think it was a
> passive type system though ( not 100% sure). Don't know if a similar setup
> could be fabricated for a Holley TB. Remember the motorcycle carbs are
> sidedraft. Don't know if this would have an impact on feasibility or not.
>
> Bob
> Pennsville, NJ
> -----Original Message-----
> From: Shaun.Hendricks@bergenbrunswig.com
> <Shaun.Hendricks@bergenbrunswig.com>
> To: dakota-truck@buffnet.net <dakota-truck@buffnet.net>
> Date: Tuesday, August 10, 1999 4:29 PM
> Subject: DML: Throttle Body Mod idea
>
> > 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.
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