Re: [T3] Injector interchangability?

["David V.N." <rmcevoy1@twcny.rr.com>]

Hmmm.More possibilities........
Thanks for the post!

"....the whole world , Chico. And everything in it."

David V. Nelson
1969 Fastback FI (no matter what!)


----- Original Message ----- 
From: "Martinez, Leon B Civ 203" <leon.martinez@navy.mil>
To: <type3@vwtype3.org>
Sent: Monday, December 01, 2003 4:31 PM
Subject: Re: [T3] Injector interchangability?


>
> All this talk about injection got me thinking and remembering about a Baja
squareback racer 2 years ago
> the guy who had the racer was selling it for 3000 down in Mexico , , he
told me he had frankensiened the
> D-jet EFI , he had turbo on it and custom made the runners and throttle
body , since the car was a 2300 ,
> he put the green porshe/volvo/mercedes injectors, mercedes brain, (cuz of
big heatsinks and mixture adjustment
> ) internally modified the pressure sensor to move mechanically in a wider
range , take one apart you can
> see the adjustments and the springplates.He told me that the PS only cared
about vacume, the key was
> vacume for the sensor at the intake behind the throat , fuel pressure was
the same. He told me that the
> original runners were really not the problem at all , he demonstrated a
giant chrysler engine (8L )that had
> a tiney tiney carb like thos big vw ones on his monaco . He told me that
air velocity would suffer at
> high speeds because the throttle body intake was barely enough for a
bigger engine at higher engine speeds .
> He told me all engines with different cams and airflow designs would make
the task of adapting the D-jet
> efi difficult , each engine had to be set up differently and yes you need
an air/fuel ratio meter or exaust
> analyzer to make the adaption correct for slow medium and high speeds.
Possibly adjustment of the PS
> may be required for the mixture but one must check the entire RPM range to
see if the internals of the
> PS is set up for the engine, different bellows have different pressures ,
they have numbers on them ,
> spring plate stiffness and adjustments may take a long time to get right ,
writing data down at every change will ensure
> that you do not repeat mistakes . Some PS have just the bellow others ahve
a bellow plate that
> is part of the enrichment circuit on the brains newer than the c brain ,
when this ps is placed on the c brain that
> uses the throttle switch with the  enrichment circuit , you get a very
enriched throttle pump action ,
> kind of like drilling the throttle squirter in a car.
>
> The hard part is making the engine work properly at all speeds, usually
big engines have big cams and
> different toys attached to it, like bigger ported heads , vacume
characteristics change and the main thing
> is to get the PS to use it properly and dinamically or your car will run
like a dog , kind of like a carbed
> engine with a big cam .
>
> The system only lengthens the time of of injection of the injectors , the
injectors have a flow characteristic that
> is pretty wide and uniform , the brain only does what the PS tells it ,
lengthen the injection time .
>
> I have frankenstiened my efi a bit and works beautifully except for the
melting plugs , but it took months of
> trying to get every speed and condition corrected. It purrs and runs very
smooth .
>
> I am building a 2100 right now and it will have to adapt a D-jet system to
it , ithink later I will turbo it , I have the
> turbo but the exhuast system will have to be custom made  , I will see
what I use for a throttle body.. Still in the
> junk stage for the 67 fasty , engine in peices machined by rimco .
>
> LEON MARTINEZ
>
>
>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org
>