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914World.com _ 914World Garage _ Megasquirt question

Posted by: spare time toys Feb 19 2005, 05:58 PM

Is there a web site for this. I am thinking that may be the way to go with the 928 swap over using the 928 comp.

Posted by: SirAndy Feb 19 2005, 06:10 PM

QUOTE (spare time toys @ Feb 19 2005, 03:58 PM)
Is there a web site for this.

http://www.bgsoflex.com/megasquirt.html

Andy

Posted by: lapuwali Feb 19 2005, 06:26 PM

There's also a message board:

http://www.msefi.com

There's a LOT of information out there, and a very active community is keeping it pretty much up to date.

Posted by: fiid Feb 19 2005, 06:56 PM

Uh - what's the question?

Sound be pretty easy to get the MS going on the 8.

Fiid.

Posted by: scott thacher Feb 19 2005, 09:48 PM

why not use the stock computer, should be easy enough to get it to work. i mean after doing the obd2 on the suby, the 928 would be easy.

send me a wiring diagram so i can look at it, and maybe save you some time

Posted by: fiid Feb 19 2005, 11:34 PM

you must have brass balls to get the stock computer running on that thing. :-)

didn't the 928 have mechanical fi???

Posted by: rick 918-S Feb 20 2005, 12:16 AM

MHO, If it ain't broke don't fix it. Porsche spent a small fortune one the factory injection and it works. You just need to get a pair of reading glasses and stair at speggetti on paper for about a week.

Posted by: lapuwali Feb 20 2005, 01:04 AM

The early 928 used CIS (aka K-Jet), but I think the later ones went to Motronic. If this is any early K-Jet engine and there are any electronics involved at all, it's CIS w/Lambda, which used a servo valve alter the "control pressure", and thus the fuel mixture. The valve was controlled by a simple ECU that read an O2 sensor, but getting MS to make that work would be nearly impossible, so if that's the case, keep the stock ECU, add an O2 sensor, and leave the engine unmodified. Or, be prepared to switch to EFI of your own making (using a later EFI manifold and injectors, and something like MS).

Adapting MS to Motronic hardware should be much easier, though you'll need to do fuel AND spark, which is a somewhat more "advanced" thing to do with MS in its current form. It can be done, but the learning curve is a lot steeper. Doing the EDIS setup would be the best bet here. You won't be using the airflow meter with MS.

Posted by: spare time toys Feb 20 2005, 08:09 AM

One of the things I need to figure out to make the stock computer work is a flywheel sensor. They use it to pick up rotation to turn stuff on and with the adaptor I no longer can mount it in a way for it to work. I may be able to move it to pick up one of the cam pulleys and let it count those notches. I dont think it being half of crank speed would be an issue for that, or mount it down by the crank drive.

Posted by: MecGen Feb 20 2005, 08:23 AM

Hi Guys/galls
Thumbs up on the swap, I always loved the idea.
The crank sensor might be a huge deal, the ecm see everything at the wrong speed, half speed, all calculations will be off, I doubt it would start.
I need the exact year of your motor or injection you have, I will look through some documentation at the shop. I am sure it could work.
Let me know if you need a long distance hand.
WBR
Joe

Posted by: rick 918-S Feb 20 2005, 09:53 AM

QUOTE (spare time toys @ Feb 20 2005, 06:09 AM)
One of the things I need to figure out to make the stock computer work is a flywheel sensor. They use it to pick up rotation to turn stuff on and with the adaptor I no longer can mount it in a way for it to work. I may be able to move it to pick up one of the cam pulleys and let it count those notches. I dont think it being half of crank speed would be an issue for that, or mount it down by the crank drive.

Crap! I thought I remember asking you if you had a crank sensor! I thought I recall you telling me you didn't have one.

Post some photos of the flywheel part of the sensor. (trigger Wheel)

What is the diameter?

Where does the sensor attach?

I have an idea....

I have a 928 flywheel here. Send the trigger wheel to me and I'll figure out how to attach it to the back side.

Posted by: lapuwali Feb 20 2005, 10:58 AM

If there's a flywheel sensor, it's definitely Motronic. The flywheel sensor adapting is done regularly by 911 guys putting Motronic engines in early cars. You'll very likely need to notch the bellhousing to fit the sensors.

Posted by: scott thacher Feb 20 2005, 11:19 AM

here is a what maybe a stupid question... how many notches does the pick up need to see, i mean if it is like a ford edis, which has 32 teeth ( i think i am wrong but go with me here ) and 2 teeth missing for it to pick up on, if you made a wheel that had 64 teeth with 4 missing teeth, that would correct the speed varation from crank to cam, or it as simple as that, just double the pick up notches.

Posted by: MecGen Feb 20 2005, 11:32 AM

Hi
The ecm looks at the number of triggers (teeth)
And the time it takes to make a revolution.....so
logic tells me, one rpm is one rpm, shouldn't matter here, where it getts the right signal/speed, is not important.
But why does my gut tell me its more complicated then that. I would check out the sites mention before, I am sure it can be modified to fit the trans, safer.
What year is donor ?
WBR
Joe