[Diy_efi] Why I asked about the GM V-6 MPFI

[Arby]

Dakota Digital makes a box that will adjust your PPM's to what ever you 
need.  I've seen them for about 80 bucks.  Haven't used one yet but plan to 
in the near future.

Arby

----- Original Message ----- 
From: "Joe Boucher" <boucherj at prodigy.net>
To: <diy_efi at diy-efi.org>
Sent: Sunday, August 13, 2006 8:27 AM
Subject: [Diy_efi] Why I asked about the GM V-6 MPFI


>I have a '89 325i.  I also came across a turbo just right for a 2.5 liter
> engine.  Turboing the 325i is a big temptation plus playing with the fuel
> and spark maps.
>
> BUT, as best I can tell, no one has hacked the Motronic 1.1 FI computers 
> to
> any kind of detail like the GM ECU's.  Which surprises me, as the size of
> the memory chip used in the Motronic is really small.  2k or 4k?  And that
> is the size of the maps and programming.  But I could be wrong.
>
> So, the voices in my head keep telling me to piggy back a GM system onto 
> the
> 2.5.  The list of road blocks to do this are short.
>
>
> Engine timing.
>
> The MPFI system would require some kind of crank trigger.  The spacing of
> the disk slots on the crank could be copied on to a computer controlled,
> laser cut disk and the disk sandwiched between crank pulley and the 
> harmonic
> balancer.  The BMW crank position sensing system (60 minus two knobs) is 
> on
> the harmonic balancer and the bracket could be useable for mounting the GM
> sensor or maybe the BMW sensor would work.
>
> Or, use a TBI system.  There is a lot of room in the BMW distributor cap. 
> I
> haven't looked at the details, but mounting a GM HEI reluctor ring (the
> pointy thingies) might be easy.  But turboing would be easier with 749 ECM
> code.
>
>
> Speed input to the ECM.
>
> The hardest part of converting my carbed '81 Suburban to an '89 TBI system
> was the speed sensor situation.  The 700R4 on the back of the TBI engine I
> bought had the electronic sensor and not the cable drive.  After 
> installing
> everything, successfully running the car down the road, THEN figuring out
> the output of the tranny speed sensor needed conversion to a step wave, I
> should have pulled the tranny and had the output shaft converted to a 
> cable
> system and bought the in-line speedometer cable sensor.
>
> The BMW uses a sensor on the differential which detects the pinion ring
> teeth.  I doubt the number of teeth will equal 2000 or 4000 pulses a mile.
> Some kind of converter circuit is possible, but I can't do that.
>
>
> Knock sensing.
>
> BMW didn't start using knock sensors till 1991.  Mounting a GM knock 
> sensor
> on the bimmer block might be a challenge.  I have a Bosch knock sensor off 
> a
> Volvo, but am not sure it operates the same as a GM sensor.  I don't HAVE 
> to
> have a knock sensor, but it sure would be nice.
>
>
> Any thoughts would be appreciated.
>
>
> Joe B.
>
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> Subscribe: http://lists.diy-efi.org/mailman/listinfo/diy_efi
> Main WWW page:  http://www.diy-efi.org/diy_efi