Atomisation Re: Intake manifold construction, intercoolers

[Mos]

On Tue, 11 Dec 2001, Dave Williams wrote:

> -> So do "conventional"[1] port injectors at any point in the rev/load
> -> range produce better fuel delivery then carbs?
> 
>  "Better" in the sense of "more appropriate for the driving conditions
> at hand?"  Yes; port injection (more particularly, timed or "sequential"
> port injection) can give better cold start and cold idle emissions and
> driveability than a TBI or most carburetors.  The old side
> constant-vacuum SUs and the like with appropriate manifolding would come
> danged close, though.

I was thinking "better" in the sense of getting more power for the amount
of fuel delivered. (But come to think of it's probably an ignorant
question... ).

>  There are people who believe that port injectors shoot at the back of
> the intake valve, which is hot and vaporizes the fuel, but in most
> engines this is not true; the injector simply squirts a stream on the
> port wall or floor, where it's picked up by passing air,
> catch-as-catch-can.  Take a look at any 5.0 Mustang or Tuned Port Chevy
> and note the injectors are nowhere near the valves.  A few new-design
> engines *do* shoot more or less at the valves, but they're still a
> minority on the road.

No access to a 5.0 Mustang engine, sorry :) But a Toyota 4AGE engine
initially had single pintle injectors that seemed to squirt at the ridge
between the ports to each intake valve. Later 4AGEs had twin pintle
injectors which directed the fuel more into the ports themselves, as did
all variants of the supercharged version.

Mos.

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