Motec M8: connectors and info for re-wiring.

[ale.agos]

Hello everybody,
one of mine costumer asked me to make a new loom with the goal to interface its M8 ECU with a Judd V8 3500cc engine (ex. Lotus F1).
Actually he has the original loom but it is in a bad condition so he would like to replace it with a new one that will fit on the car's chassis / components.
Usually I don't build engine's loom because my work is focalize on data acquisition so I've build loom for that purpose in the past but I would like to do that for this costumer.
On Motec web site I've been able to find a scheme who explain what are components that need to be connect to the ECU and give info on connectors pin-out so that could be a good start for my job. What I haven't found on web site is a detailed scheme of Ignition System ( the scheme that I have refer to another drawings ) so could someone of you provide me this scheme? About connectors on ECU I will need to re-use the oldest two or I will be able to find them new? Someone of you know their part number / manufacturer ? About ECU I've seen that it has an old software write to work with DOS O.S. called E.M.P. software so any chance to use a new one software that could be run on system without DOS O.S.?
Thanks to all for collaboration.
Alessandro

[Chris Wilson]

Which Judd V8 is it? I have wiring diagrams for my Mugen Honda F3000 engine, and it may be very similar, as Judd had a large input with this unit, Has it got a distributor, with a crank position sensor on a chopper wheel on the nose of the cam, and cam position sensor inside the distributor body? I want to put my engine onto an M800, from its original Zytek ecu at some point.

[ale.agos]

Hello,
Engine is model CV, 3500cc ex Lotus F1.
I haven't see it so I can't confirm anything about its configuration.
If you know it any help or information will help me!

[Chris Wilson]

I am pretty sure this follows the Mugen Honda pattern as far as ignition triggering is concerned, I have recently rebuilt my engine and it's sat on its trolley awaiting me finishing painting the Lola tub its going back in. I'll grab some photos for you. I have regular contact with Judd (Engine Developments) here in the UK, and I original Mugen manuals, and I have wiring diagrams. I should have enough info to help somewhat. I also have contacts at Zytek who probably did the original ecu for you engine.

[Chris Wilson]

I have taken some photos of the crank and cam position sensors on my Mugen Honda V8, I think you will find your F1 Judd CV very similar to this. Now, I am going from memory when I say they are magnetic sensors, and not Hall effect or photo cell type, so want to check tonight in the manual. The cam sensor is driven off the 1/2 crank speed quill shaft that drives the distributor and the alternator. Photos are at:

http://www.chriswilson.tv/sensors/sensors.html

Hope that helps a bit, let us know how you get on. I could probably scan the wiring diagrams if you need them, has the engine got its original loom on it still?

[MarkMc]

The detail drawings we have for ignition systems depend on the particular ignition system. Our ECUs can generally run any ignition system. You would really have ot be able to give me some idea about how the original system worked. Was it inductive or CDI.

The M8 was replaced by the M800 about 10 years ago so the latest softeware (version 6.0) is the last development for the M8. The M800 has Windows software and would probably be much easier to work with tham the M8.

Does the engine have a synchronization sensor on the cam or in the distributor?

[Chris Wilson]

The CV has a disi quill shaft drive at 1/2 engine RPM, and the cam position sensor is on one end of this shaft, just as in the Mugen. The stock ignition was Lucas Opus CDI in a separate box, of notorious unreliability The disi merely distributed HT to the relevant cylinder. HTH the original poster a bit. A friend has a CV for sale right now, if necessary I might be able to grab photos, but I think it's still in a single seater tub.

[ale.agos]

Hello everybody,
As explained in previous post I'm going on with the design of a new harness to use for connect Judd engine and M8 ecu.

With the goal to understand how the ecu has been connected with the previous harness i did a scheme of it and, doing that, i discovered that the ecu was connected in a wrong way for that concern firing order and injectors.

So with the new harness i will redo connections in the right order, also I have some questions about coil box and its connection to M8

Actually the ecu has coil unit connect with a 12 pin connector. Connector's pin-out should be the standard one due to the fact that the previous owner of the engine said that coil unit could be replace without any change with that one who is used on Zyteck KV engine. About this point effectively the connector is the same of Zyteck connector so I guess that also its pin-out should be the same.

It is an ITT Cannon 12 pin connector, its p/n should be: 6026-14-12SN, connection between ECU and coil box / car's harness are:

A = Motec M8 pin 3A - IGN1
B = Motec M8 pin 13A - gnd
C = not connected
K = Car's harness + 12 Vcc
F = Car's harness + 12 Vcc
L = not connect
M = Gnd

On Zyteck's engine connections of that connector are identified as:

A = IGN Trig 1
C = IGN Diag 1
K = +Ve supply
F = S/W supply
L = Engine Gnd
M = IGN Gnd

Basically seem that connections are OK, Zyteck has on pin F a 12 Vcc supply who came from Ignition switch, on my Judd's cable 12 Vcc is not under switch and also I don't have the Ign Diag 1 connection on pin C who I guess is a diagnostic signal for the ecu...

What do you think about above connections? Do you think that they are OK?

About the alternator I will need to connect it in some way to the ECU? For that I have seen on the car seem that it has just 3 wires who are independent of all and that connect it to a device who will recharge car's battery (this last one device is connected to car's battery positive e negative poles).

About ECU way of work I have some questions on sensors that are connect at know and that ones that I should connect as optional.

Actually ECU has:

- Ref sensor, - Sync sensor, - Air pressure sensor (connect on pin 28A that in Motec's scheme is label as MAP sensor); - Throttle position sensor; - Air Temp sensor; - Engine Temp sensor (Water Temp); - Oil Temp (connected on Aux temp 1 - 8B pin).

What about Lambda sensors? I've seen that ECU has 2 different input for use 2 sensors. Do you think that if I will fit them I will have an improvement in engine control / performances? Doing that I will need to remaps ECU or it will be able to use immediately "information" that will come from sensors? I've seen that Lamba sensors are 2 wire sensor so I guess they are the simple one type that don't read constantly the lambda value but that one who has just an "on/off" output dependent of status of lambda ratio. I'm right in my supposition? Do you suggest to add lambda sensors or not?

About knock sensor what do you suggest? Add it or not?

Last one question is about traction control feature of the ECU... I've noticed that on the original harness there was 3 wheelspeed sensors connected to pins 16A, 15A and 4A. Has the ECU a real traction control feature? How it works? Do you suggest to keep it or reply it with a more sophisticated model? (Actually on the others F3000 cars that we have there is fit a traction control unit made from Racelogic uk).

Hope that someone will be able to give me some suggestions, i asked around but at now anyone has answered me...

Regards to all!

[Chris Wilson]

Hi Alessandro, sorry for delay getting back to you by e-mail. I had trouble finding the copy of the spark box wiring diagram. Now, when you say the Zytek spark box is it actually a Lucas CDI unit? A big alloy box with a steel base plate? I have linked to a photo of the inside of mine below. I am not aware of Zytek doing their own CDI unit for these engines. I attach a pdf file, hopefully, showing how the Lucas CDI box is wired up. This should help.

Is the car for hillclimbing? My F3000 has no real traction issues in the dry, once it gets some speed up, these things have loads of downforce, especially early cars like mine before they reduced downforce with silly car planked bottom rules

It is of course a bit of beast in the wet, but F3000 never had traction control in period, and as far as I know the M8 doesn't have traction control ability internally. I have used Racelogic stuff on plenty of road cars and it's OK, but you would have to seek advice as to how a real high revver will like injector cuts, I have only used it on road car engines. It should be fine, but I would check it out first.

If you think my Lola chassis loom diagram will help I'll dig that out, too. I have excellent contacts at Zytek and Judd, and have contact details for the man here in the UK that actually designed the Lucas CDI box, and now in retirement repairs them. He also offers a very costly modern equivalent of it using modern internal components. There's no reason you can't use a Motec CDI box if the budget permits, but ther are hundreds of historic F1 and F3000 engines still running on the Lucas boxes.

I can't upload the image files to the forum until later, my FTP app is flat out downloading 8 gigs of Bosch data via my pitifully slow line, which it's been doing all day I have therefore also e-mailed them to you direct

[Chris Wilson]

Oh, re the alternator. The alternator outputs AC from the three stator coils for rectification and regulation externally. The stuff for this is inside the Lucas CDI box. Many people fit an external rectifier as it keeps the box a lot cooler. Demon Tweeks here in the UK sell them, as do www.raceparts.co.uk. I use the external rectifier on my Lola as I bought it like that, although the original stuff is still in the Lucas box.