Subject: Location of Injectors
From: Paul
Date: 4/17/2000, 6:12 AM

Ken Powell wrote:

Hi Paul,
1.  First of all, sign me up for a 6-port intake kit.
2.  No one else has brought this up and I am afraid of looking foolish,
 but ...
It would appear that if you located the fuel injectors a long distance
from the engine that the fuel would have a tendency to 'puddle',
especially as the mixture made the turn from the top of the engine to
the intake ports (I am picturing a manifold that runs over the top of
the engine to a plenum, like is being recommended by almost everyone).
Also, the intake tubes will be cool which will promote this tendency.
At least we do not have a venturi to promote icing.  It seems to me that
the injectors should not be located over 3" to 4" away from the block.

Thanks,
Ken Powell

Tracy, Bill and I had that discussion at the camp site. 
Puddleing with four pipes and four injectors would,
I think, not be a problem. Once the puddle is full
all the fuel will then eventually go down the intended pipe.
That may be a good reason to keep the pipes downhill
all the way. You have a lot of air going down that
pipe and gasoline is volatile so it probably would
evaporate and be carried down the pipe.

It might be a problem in a low power car engine.

One carb with two or more pipes is a different situation.
In that case one pipe may get more fuel than the other pipe.
This is the classic carb/intake manifold scenario and why
it was real hard to design a carb manifold for a multi
cylinder engine in the old days.
 
There is some evidence that super high pressure injectors
help the situation. I have heard rumors to that effect.

Renault built a Formula one engine with the injectors outside
the bells pointing straight down the pipe. You could see at 
a glance if all the injectors were working.

Paul Lamar
 
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