Dan Timberlake wrote:
> The throttle body FI had some advantages over carbs.
>
> Providing equal air-fuel ratio mixture to more than one cylinder
> drawing mixture at a variety of throttle settings from a remote
> source is real tough (maybe impossible). A manifold with design
> features to improve cylinder filling is even less likely to be able to
> provide even AF ratio over a wide operating. It is Best to keep the
> air distribution and fuel distribution functions separate, and port
> injection does that.
> Whenever emission regulated cars jumped from carburetors to fuel
> injection pretty much all the poor driveablity problems disappeared
> instantaneously.
And those tbi's had the injectors above the throttle plates.
>
> I figure that if the injectors are above the throttle plates, or
>
>>>anywhere<< but in the cylinders' individual ports, then the HUGE
>
It's still in the individual ports, just above the butterflies instead
of below them. The first instinct is to think the spray is going to
hit the throttle blades, puddle, and drip into the runners. I don't think
that is going to happen, at least, not in such a big way.
> advantage of guaranteed even fuel distribution is likely lost.
>
At part throttle I believe it will run fine. But i'm worried about
the idle quality. So far I've called 2 prof fuel injection organizations
to ask about this. One said they had already done that using a Hilborn
intake on a hemi and it ran great. The other had not done it but
thought it would be no problem. The more I think about it, the more
I don't think it will be a problem either. A lot of the CanAm
guys did it too, welding bosses directly to the ram tubes, but admittedly,
they didn't have to worry much about low speed driveability.
Still, the cars *had* to idle or they'd have never been able to
make it around the track on the first few laps waiting for the
green flag. . .
> If the goal is simply a good running engine (definittely a worthwhile
> goal) , then the hi mount injectors can be pretty rewarding.
>
> A full electronic control with accurate and appropriate fuel and
> ignition map is a wonderful thing, but does not come in a UPS box.
>
thanks!
B
> On Tue, 16 Oct 2007 21:26:15 -0400, Bill <edison@[EMAIL PROTECTED]
> wrote:
>
>
>>Hi-
>>
>> Have a few old FI intakes and want to convert one of them to EFI but
try to
>>avoid welding if possible. I notice that some throttle body injectors,
as well
>>as a few mechanical FI setups have injector nozzles *above* the throttle
blades
>>and wonder if anyone has tried this with EFI, and if so, how good or bad
did it
>>idle? This kind of setup would make it easy to make EFI adapters for
older
>>Hilborn and Crower type intakes by adding an intermediate piece (to
mount the
>>injectors) between the ram tubes and the throttle blades.
>>
>> Any thoughts?
>>
>>cheers,
>>Bill
>
>
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