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Re: I wanna big throttlebody!!



>Rich Garrett
>12/20/96 12:40 PM
>
>
>>Modify the existing manifold - the manifold itself is pretty open, the
>plate that the t-body bolts to is the restrictive part.
>
>Got it!
>
>>Well, you're right, basically, but think of it this way - an engine is an
>air pump, the more air (fuel) it can process, the more >power it makes.
>So, a throttle body is conceiveably useless on an otherwise stock engine
>because no more air is trying to >get through it.  Think of a supermarket
>with 15 cashiers but one tiny door.  All the cashiers are busy, so
>management adds 3
>>...
>>Make sense?  Kinda silly analogy, but.........
>
>Makes great sense, thanks!
>
>>...
>>What can you do to make the engine flow more air?  Right!  Bigger valves
>would work,  that's like a bigger door -OR- >opening the door
>wider......the valves open .403" stock (roughly, something like that), so a
>bigger cam might open the >door/valve .423" per revolution. Make sense?
>That's *really* remedial, but the idea is there - also, cams are measured
>in >duration, IE 268 or 272 - that's how many degrees of rotation the valve
>is open.  More duration, the door is open longer, lets >more air in, with
>drawbacks being lack of low end torque, lumpy idle, etc. So, a cam can let
>more air through the engine, >making the throttle body more effective. If
>you have any more questions, I'd be happy to try to answer them.  Hope this
>>helps!
>
>So, installing a better cam would also involve adjusting things like
>timing, possibly driveshaft (powers the pistons?), etc. so that the longer
>duration integrates with everything else? By opening the valve more, the
>duration is longer, anyway, so the timing of the entire piston cycle
>changes.

Well, sorta.  The typical aftermarket cam can be installed just like the
stock one, but advancing/retarding the cam can help emphasize power low or
high in the rpm band.  This would be done with an adjustable cam sprocket.
You pretty much have to adjust the timing to r&r the camshaft, but stock
specs should work, although advancing the ignition timing seems to help in
some cases.  No adjustment to the {driveshaft} crankshaft is necessary with
the typical aftermarket cam.  You've got a pretty good idea of what's going
on so far, maybe some discussion (even without Meze) on this will sprout
up.  I left the rest of the article this time, big snip next time!  TTYS,
happy holidays everyone........


Mannix

>
>Thanks for the info! Hopefully, I'm not the only one out there learning
>something...... >;->
>
>Rich


Heh, did'nt realize it was you, Rich!


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