DIY_EFI Digest V3 #439

[talltom at espace.dcl.com]

>
>From: Matt Bossard <mbossard at bigfoot.com>
>Date: Thu, 24 Sep 1998 14:36:37 -0700
>Subject: Re: Caddy 472-500
>
>- ---MrCad472 at aol.com wrote:
>>
>>   Yes, I have seen the Cadillac DPFI system on a couple of cars. It
>was
>> available from 1975-76 on the 500ci engine. It had a 2bbl throttle
>body
>> mounted in the center of the intake like a carburator and a fuel
>injector for
>> each cylinder. I really don't know that much about the system's
>particulars,
>> though.
>>
>> Scott
>>
>>
>
>Scott, I suspect from the name that you might be doing something with a
>Cad motor...?  Just curious.  I am adapting a '95 5.7L truck TBI to a
>Cad 500 (also using the 4L80E trans).    I was planning to use the
>Edelrock aluminum intake with an adaptor for the 2-bbl GM throttle body.
>
>However, I wonder if I could use that '75-'76 Cad DPFI intake instead?

Yes you could, but I'm not sure it's necessarily the best option.

>Are the injectors actually located at the intake ports? 

Yes.

  I wonder if
>the runner-design on that intake is better than on the stock carb
>manifolds (wasn't too great).

They look largely similar, but that's an assumption I wouldn't make. I 
do know that 425 manifolds have smaller ports than 472-500's. (I have
both.)

>Now if only I could find one of those DPFI setups....
>
>Matt

Well now, just how bad ya want one??

>
>------------------------------
>
>From: "Gary Derian" <gderian at cybergate.net>
>Date: Thu, 24 Sep 1998 17:30:51 -0400
>Subject: Re: Caddy 472-500
>
>I misspoke a little.  The Bosch D-Jet is based on original Bendix patents
>from the 50's.  I once interviewed at Bendix in 1974 and saw a Cosworth Vega
>in their lab.  I know the Vega injection used Bosch parts for sensors, etc.
>The Caddy systems I'm not so sure about.  Even if they did use some Bosch
>components, I would not be at all suprised if a Bendix guy claimed it was
>all Bendix, after all, Bendix did invent it.
>
>Gary Derian <gderian at cybergate.net>

They look a lot alike, use bosch components, but are NOT the same. The 
Caddy runs 37-42# fuel pressure and the (d-jet)Mercedes uses 29.5#.
Further the Caddy uses the same part no# for coolant and manifold sensors
with resistance that's different from either of the sensors the (d-jet)
Mercedes uses, which are two separate designs.

>
>From: mrvette <mrvette at bellsouth.net>
>Date: Thu, 24 Sep 1998 18:57:43 -0400
>Subject: Re: Caddy 472-500
>
>Al of those systems are rather rare, the most common was i the  Seville series
>using the olds 350 engine....a
>the sedan devile with 425 caddy engine was very rare,

I wouldn't go quite that far...

 and the 500 inch version I
>have never even seen,

I've seen several.

 and only heard of two people in ten years that have seen
>one,

Better make that three...

  noone that has actually worked on one or owned one....    very very rare
>indeed......GENE

Well if I remember right the r value depending on temperature varies from
300-2600 ohms for ALL the sensors, and the manifold pressure sensor
is in the ecu, similar to a v-12 jag, as compared to a d-jet system
having a separate manifold pressure sensor.

Better change that from noone to one...
>
>From: mrvette <mrvette at bellsouth.net>
>Date: Thu, 24 Sep 1998 19:00:48 -0400
>Subject: Re: Caddy 472-500
>
>The multi-stage switch on the t-body (position sensor)  was, and the water
>temp/air temp units may have been, Bosch....but that was all, far as I can
>tell....GENE

That seems possible to me, with the addition of the fuel pressure regulator.

>
>Gary Derian wrote:
>>
>> I misspoke a little.  The Bosch D-Jet is based on original Bendix patents
>> from the 50's.  I once interviewed at Bendix in 1974 and saw a Cosworth Vega
>> in their lab.  I know the Vega injection used Bosch parts for sensors, etc.

I believe Mercedes started using d-jet's in about 1970.(Mine's a 72)

>> The Caddy systems I'm not so sure about.  Even if they did use some Bosch
>> components, I would not be at all suprised if a Bendix guy claimed it was
>> all Bendix, after all, Bendix did invent it.

Caddy didn't use it until 1975.

>>
>> Gary Derian <gderian at cybergate.net>
>>
>> >When I was playing with that system some 8 years ago, and putting it on the
>> >Pontiac,  I talked to the original Bendix engineers in Newport News Va.
>> they
>> >said it was their own system developed for GM...and specifically done for
>> those
>> >engines....the Olds 350, caddy 425, & 500...
>> > totally differant than anything VW/Bosch could have done....

The interesting thing to me was that ALL of the above eng's used the SAME
injector... 37#/whatever

>From: dave.williams at chaos.lrk.ar.us (Dave Williams)
>Date: Thu, 24 Sep 1998 17:02:00 -0500
>Subject: Re: assmeblers and disassemblers
>
>- -> Scott, I have a few questions for you,  I see by your bi-line that
>- -> you must be driving a 472-500 ci caddy engine.....Do you know for a
>- -> fact that these engines EVER came from the factory with that old
>- -> analogue Bendix DPFI system on them? have you seen one with your own
>- -> eyes?
>
> Let's see, it was 472, 500, then down to 425, and down again to
>something like 368, which was the one with the Bendix FI, right?
>Anything from the 368 ought to be useable on the 500.

Uh-huh. The 368 I think used a super mini cheap throttle body, and there
were two sizes amongst the rest I believe.

> True, it's a different system.  But there are strong similarities
>between the DFI and the Bosch D/L-Jet - Bosch licensed Bendix' injection
>patents and derived technology in the mid '60s, where it was basically
>gathering dust from the vacuum tube days.  Bosch took advantage of the
>advent of the transistor and developed the Bendix system into a
>marketable product.  In the late '60s Bendix foresaw a renaissance for
>EFI with the coming of smog legislation and did their own modern
>interpretation of the Electrojector.  The system they delivered to
>Cadillac in the mid '70s was much simpler than their development models
>in order to cut the lead time and price, which was a factor even for
>Cadillac.

Well that and they had to do something to try and catch Mercedes...:-)
(Which in 76 went back to mechanical fuel injection.)
>>
>There has been a Caddy 500 CI intake kicking around our shop for about 10
>years or so, was used as a training aid. I cant remember the story on it,
>but believe it to be new. It was complete with injectors, throttle body
>and TPS and IIRC the ECU was also with it. I will try and remember to look
>for it next week.


There is also another alternative. There was an outfit out of Utah I think
that made a adapter that fit between the block and heads of the caddy and
the intake manifold that mounted a 385 series Ford intake manifold. This
has a much wider support in aftermarket and factory configurations, including
port fuel injection.

I think they were trying to get about $300 for it. (the Ford ports are oval,
the caddy rectangle, and the transition takes place in the adapter.)

>
>From: mrvette <mrvette at bellsouth.net>
>Date: Thu, 24 Sep 1998 20:35:36 -0400
>Subject: Re: Caddy 472-500
>
>Jim, I want that system,  the manifold, and rails, and the distributor are
>important, t-body and sensore also.....If I can pay you for it, lemme know....IF
>it all fits the 500 ci caddy engine that is.....GENE

Well if ya don't do any good there and still want one I can probably
rumage one up.(I think I got one, and I know one that's in service..)