Juha G

As some of you know, I bought the Motec M600 engine management system last spring but haven't gotten around to installing it until now due to too much work lately, which is good I guess. I was also very close to purchasing a GT3 engine but was swayed away by a Porsche mechanic. Air cooled should stay air cooled... =)

A little background on the project; I dynoed my car in Fall 2009 to get a base line hp/tq before my top end rebuild. The car showed 279hp/339Nm with a very spikey torque curve which led us to believe the car was running a bit lean and the ignition a little too much retarded. White tail pipes after track work confirmed the lean condition.
Later on the oil burning was found out to be user error (too much oil in the sump...) and not due to worn out valve guides.
As a result I did not go trough with the top end rebuilt but opted to get the Motec engine management system to get the fuel and ignition maps corrected.

My aim is not to make more hp/tq but just to make the engine run better and safer on the track. Obviously there will be some power to gain as well by optimizing the fuel and ignition maps.

I did not want to touch the original engine wiring harness so I built a adapter harness that plugs into the original 88-pin connector.
It was a lot of research and some help from Colin from 9meister but finally the harness is ready and working.
It is all open now but once everything is working, I will seal it properly into a box.
Switching between the original Bosch Motronic 5.2 and the Motec M600 requires only unplugging the motronic box and plugging in the motec. i.e. 15seconds when the drivers seat is removed.

Now we are in a situation where the Motec is connected and functioning well. All sensor inputs (TPM, RPM etc.) are working, we get ignition and fuel. We tried to start the car this morning but found out the spark was too weak.
A little further research of the wiring diagrams showed that on the Bosch 5.2 the ignition control unit (spark amplifier) is integrated on the ECU whereas on the older (up to 95) cars with the Bosch 2.10 it is a separate unit in the engine compartment.
The Motec does not have this function so I have to get an external amp that will be installed below the driver's seat as well and the ignition wiring (of the adapter harness) needs to be run trough the unit.

I am really anxiously waiting to get the car running and tuned. I will post an update when we have done this.

Some photos:

http://m3supercar.1g.fi/kuvat/993/Motec/

Adapter harness:


Almost there:

V

Looks great Juha, keep up the good work buddy !

haygeebaby

Nice project.
Why did you go the M600 over the other models JG ?
Will you be installing larger fuel injectors and a cone air filter ?
Who will be tuning the Motec for you ?

I'll be watching to post as I have too been looking into a Motec conversion.
Very interested to see how it goes for you.

Regards
Ken

Juha G

The M600 is for 6-cylinder engines and I don't see any benefit to get the more expensive M800.
We will see if the stock injectors are big enough, if not then I'll get bigger injectors.
I don't think a cone filter will help anything though.
A friend of mine will tune it, he has tuned road race and rally cars for his entire life. The 993 is in good hands!

I will keep you posted.

trophy

Hey Juha, Looking good... I have been doing the same work with a ViPEC computer (Also from Australia)
I have made the adapter harness just as you have. I also ran a MAP sensor as well as a WideBand O2 sensor.

I have got my car started and idling very nicely, still working on some of the ignition mapping (Managed to get an original complete map from the car) if you need it i can send it to you. Need to spend some time on cold start etc as the temps here in canada are starting to drop working on the car that won't cold start will be a problem.

Make sure when you install the ignition module you put it as far from the ECU as possible, they can cause interference with the ECU.

Looking forward to some more updates.....

Juha G

Steven,
Vipec should be great too. Let us know when you get the car tuned.

I agree with you on the cold starts; it is not easy to get it right because you can only try different adjustments when the car is actually cold. It will take some time (read weeks) to get it correct.

We didn't install a MAP sensors. I am under the impression that MAP correction is really not that accurate at all. Instead we are using the alpha-N method. (reading the throttle position against the rpm.)
The manifold absolute pressure is commonly used on forced induction cars but alpha-N is better suited for a naturally aspirated engine due to greater accuracy.
Since I'm using the car mainly on the track, I want the engine to respond to throttle inputs as accurately as possible.

beentherebaby

Fun project.

Engine mapping without an engine dyno is always the challenge as you can't control any of the variables.

MAP and alpha-N systems both work well if the resolution is good on the sensors.

Hope it works well when you're finished.

trophy

I can set up the ViPec with both Map and Alpha-N, without issue. A lot of the guys I have spoken to they like the MAP especially if the car is run at altitude (i am at 3500ft) It is easy to switch between the two or have both working.

Once the car is starting, running and responding to all inputs the car is off to the Dyno for proper tuning....

matt777

and then you can think about marketing some conversion harnesses

trophy

That has crossed my mind......

NineMeister

Juha,
You need to fit a MAP sensor and use it with a correction table for the fuelling. This way, when the idle valve opens & closes to stabilise the idle speed, the engine will "see" the variation in manifold pressure and adjust the fuel accordingly. Without MAP correction it will not idle sweetly with the idle valve working. Use the MAP correction table in the Motec file I sent you and do not be tempted to change it as it is set according to the laws of physics w.r.t. air density (and likewise with the AT fuel correction table).

You can use the 993RS ignition amplifier & heat sink which should bolt directly onto the ecu mounting plate - all 993's had a twin output amp under the seat, it's only the 964's which had dual amps mounted to the coils in the engine bay.

NineMeister

The downside is the availability of the 88 pin socket which are required to make them on a commercial basis. AFAIK these are only available from AMP and the minimum order quantity is in the order of 200 units. If someone can tell me otherwise & suggest where to buy them from in limited numbers I would be more than happy to make up looms to order.

trophy

This is what I bought for my loom, it makes it look very tidy..... and reasonably priced.... It's for the 55pin, I cannot see one for the 88pin sorry.

http://www.diyautotune.com/catalog/d...pin-p-415.html

shanepotter

Juha, I enjoy watching the progress your car has takes. I still remember this car as my first 993 "ride along" aka "hot lap". I'd venture a guess Chuck P. continues watching your threads with happiness. All the best!

Juha G

Thanks for the heads up Colin! We didn't even think about the idling (my friend is used to race cars and usually they don't idle that well or at all...)

With regards to the 88-pin socket, I have another friend who has fabricated many custom ECU's for BMW's that have the 88-pin socket. He also ran into the same problem, the 55-pin socket you can get easily but the 88-pin is only available on 200pcs minimum order.
What he has done is buy used 88-pin Bosch ECU's (and automatic transmission boxes etc.) from ebay for anywhere between 30-50euros/piece.
That's not that much after all when you count in that you get a very good enclosure as well.
If for some reason you ended up buying 200pcs of those 88-pin connectors, I'm sure my friend would buy 50pcs from you.

You mentioned that all 993s had the dual output amp below the driver's seat. You must mean all cars up to 95 with the Bosch 2.10!?
My car has the Bosch 5.2 and the amp is built-in in the box it self.

So you know Chuck? It's a small world!
He surely is watching his old 993 like I am watching my ex-GT3. (we traded cars in 2008)
His heart skipped a beat when I posted my crash video on the racing forum two weeks ago. Just to find out it was the BMW race car I crashed during a enduro race, not the 993...hahah!