MS and SINGLE Extrudabody.

So, I was looking at the extrudabody site and at Moe$ TEmpo conversion and wondering if a single extrudabody would be a nice way to make a TBI unit. 1-3/4 = 44.45mm, so you could slap a 45mm throttle body right on a head and have a pretty smooth flow, and I'm fairly certain that a single injector could handle the needs of a typical loghead 200. If not, they also make standoffs to add a second injector above the throttle plate. http://www.extrudabody.biz/servlet/the- ... %29/Detail

Wouldn't be too expensive, either:

Extrudabody unit, w/air horn and adapter plate: $159
Injector: $75
TPS: $40
Fuel rail w/ fittings:$75 (or you could make one cheaper)

Not sure that there would be any advantages over a TEmpo unit, but it sure looks cool

They certainly do look nice.

The hurdle would probably be with injector sizing. You need to be able to flow about .5lbs of fuel per HP/hr at about 90-95% duty cycle. For a six cylinder engine, that roughly equates to six 14lb injectors for a 150hp engine.

If you try to do that with only one injector, you'd need a single 84 lb (6x14) injector. Getting the pulse width short enough to idle well on such a large injector would be an issue, though not insurmountable. If you could add a second injector, or even a third, it would be easier to deal with.

That's one of the biggest issues with TBI.

Yes, so I have have surmised with my recent research on whether the tempo TBI would be suitable for a performance engine. Big difference between having one injector or two, which makes the common GM TBI a much better choice.

However, back on the issue of the extrudabody I think this would make a great unit for a triple setup, either with the offy manifold or custom as many here have made. I'm fairly certain you could program the Megasquirt to not activate the injector on the outer two TBs until the TPS was past a certain point, thus you could have a progressive triple injection setup. That would be a very cool modernization of this classic hot rod setup and would allow a small, accurate injector for smooth running and economy on the main carb with no shortage of fuel when the secondaries open up.

falcon fanatic,

It would be better for fuel distribution to have all three TBs running all the time as opposed to a progressive system. The injectors can handle the increased fuel demand better than carbs.

And with a single fuel mixer (carb or tbi) on the log head, wouldn't you still have the god-awful distribution issues at idle and cruise?

i didn't say it was a "good" idea. i just said it would be "cool" 8)