Re: personal D-Jet opinions (long)

[Dirk Wright <wright@pioneer.uspto.gov>]

On Wed, 28 May 1997, Gregory M. Merritt wrote:
> 

> 	D-Jet really isn't that bad.  I wonder if anybody can honestly say >
both "I understand f.i. as well as or better than carbs" AND "I hands-down
> prefer carburetion." 

I believe I can say that. Since I work at the Patent Office, I looked up 
as many of the early Bosch fuel injection patents and read many of them. 
I've also read a couple of books on Weber carbs. I prefer carbs, but not 
for any of the reasons you mentioned. I prefer carbs over D Jetronic for 
these reasons:

Documentation: There is no schematic for the ecu box - it's proprietary, 
so you can't repair it and you can't diagnose it. Weber carbs have lots 
of documentation for both diagnosis and repair. Additionally, if you want 
to increase the performance of your engine, you'll need to change the 
fuel system. Since there isn't much information on D Jet, you're 
basically guessing in order to get more fuel out of it (or change it's 
responsiveness). Jetting for Weber carbs is a well known science (and 
art). 

Cost of repair and availablity of parts: D Jet parts are becoming hard to 
find and are much more expensive than Weber parts. For example, both the 
wiring harness and the auxiliary air valve are unavailble new for my 914. 
After 20-odd years, the wiring harness in any engine will be a mess. 

If the law in your state allows it, I recommend switching to carbs. Fuel 
injection is great, it's just expensive and not well supported anymore. 

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Dirk Wright 		wright@pioneer.uspto.gov 	       1971 BMW 2002
"I speak for myself and not my employer."               1974 Porsche 914 2.0
"A real hifi glows in the dark and has horns."            1965 Goodman House
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