[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]

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 .


List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]