Motronic conversion

[Anth73]

Hi,

Another decison point with my 3Lt V6 conversion is whether to stay with the stock L-Jetronic setup or convert everything over to the newer and better Motronic fuel injection as used on later 75 3Lt V6's. Whilst the engine is on the shop floor we're going to bring it up to Potenziata / 164Q specs by shaving the heads to bump compression up to 10:1 and fit S cams.

It seems logical to also update the ECU to Motronic and thankfully my engine block has the castings for the crank sensor.  Things get a little complicated with the different versions of Motronic used on the standard 75, 75 Potenziata, 164 and 164Q. This is what I understand:

- The 75 and 75 Potenziata used Motronic ECU 0.261.200.141 with one of two possible chipsets, 1.267.355.737 (9AE3) used mainly in standard 75's and 1.267.356.097 (BF43) used mainly in Potenziata's. I understand the 097 chip can be tuned for higher octane fuel by grounding pin 11. This chipset is likely going to be impossible to find now given the limited number of 75 Potenziata's sold here.

- The 164 used two versions of Motronic ECU, 0.261.200.117 in standard spec and 0.261.200.130 in 164Q (164S in US market). I don't know the differences between these ECU's. I gather with the number of unloved standard 164's around that the 117 ECU will be far easier to source.

I also understand that the airflow meter from a Motronic 75 or 164 is far less restrictive. There are also differences with idle control through the use of the Auxilary Air Valve on 75 Motronic  V6's compared to a newer idle control system (can't remember what it's called) on 164  motronic engines.

So wondering what ECU and related kit like airflow meter I should be targeting? Otherwise do I not bother and just go a programmable ECU like megasquirt? This will be a road car only so the later may be a little harder to justify on a cost basis.

[Duk]

Just go for a decent programmable computer.
There's nothing about the 12v spec Motronic systems that makes them worth trying to impliment, except for the crank angle sensor (for your programmable computer).

[105gta]

Anh73, it certainly a worthwhile conversion if done correctly, both of the 75 systems are not the best choice as they retain the factory idle aux air system, I suspect the diff in part no.s is for the markets. Like the USA using a ecu controlled valve for the evaluation emissions.
The 164Q uses a different ecu but not worth the extra expense as hard to find. The best for a conversion of the standard 164 ecu and afm and use the idle valve in place of the factory 75 aux air valve. As it has proper idle speed control and if a/c is fitted use that wire as well to the ecu and it will idle up with ac on. Always has a silky smooth idle, better throttle response, it's easy to use the complete engine harness from a 164 only need to connect a few wires or you can convert an old Ljet harness if you want to go down that path.
Ben

[carlo rossi]

go the whole way
3X 42dnf webers
cant beat the power and the sound
or the 6 carbies of the old alfa 6

[GTVeloce]

Fully agree with Ben. As you know I am going the same way, using 164 Motronic. It's much smoother especially at idle and it won't be hard to hookup. Much quicker and easier than custom. It is also possible to play with the factory settings in a Motronic ECU as per Festy's work on AlfaBB if you want to squeeze a little out of the engine with your additions.

And plenty of bits floating about so sourcing is easy/cheap.

[julianB]

With all the work you're doing, you're still staying in the late 80s...
Any particular reason you're avoiding going to a modern ECU?

[Anth73]

With all the work you're doing, you're still staying in the late 80s...
Any particular reason you're avoiding going to a modern ECU?

Ignorance probably! I just thought the Motronic option would be functionally okay, easier and less costly for what I'm after than an aftermarket ECU like a megasquirt.

What would I expect to pay for an aftermarket ECU?

[ALFAAA]

You can use a Gotech Pro X stand alone ECU
I will be using this ECU on my 3.2 conversion


Have look at the Youtube link below

https://www.youtube.com/watch?v=dLIYSET-3Bc

[Anth73]

Interesting video and seemingly great value to buy. I will discuss it with a Hugh at Monza Motors, it also takes the restrictive AFM out of the equation too.

[julianB]

mega squirt wasn't really what I had in mind.
You could buy a Haltech E11v2 for $500 on eBay....
If you've got extractors and cams or a head port, you'll actually realise some gains.
You can run sequential injection on 6 cylinders.
Yeah you're going to have to spend time tuning it to get it run right- dyno sessions,
maybe some road tuning to smooth it out.
The biggest gain is ditching the air flow meter....

A newer Haltech that can sequentially run 6 cylinders is a bit more.
I got a second hand Motec M84 for a very reasonable price.

I can't fathom the amount of effort you're going to, to have a flashable motronic that still uses 80s technology and an AFM, that won't allow to really tune the engine in real time.

At least if the Haltech breaks, you can get it fixed....

Just my $0.02

[GTVeloce]

It might be 80's tech but Motronic engines still run very well (and reliably) 30+ years later. It is also very easy to install and requires no dyne time or finessing to get it running well. It will most likely come with the V6 if you buy a standard 164 donk but if not it would be very easy and cheap to source. You could have it installed and enjoying your GTV6 in no time. Then, down the track, if you wish for a bit more, it would not be much more work to install a programmable ECU (than doing it now while the engine is out).

FWIW, Singer Porsche offer the base engine in their cars with Motronic...

[Duk]

The version of the Motronic that Alfa used for the 12 valve engines, must have been the cheapest, nastiest version available.
1 injector channel for all 6 injectors, a throttle position switch, ignition via a distributor and 5 kilometres of HT ignition leads and they still persisted with the ancient vane/flap type air flow meter.
If you were working with the 24v engine, they had a much more capable computer and wiring loom to match the sequential injection and distributorless ignition system.

[poohbah]

Spotted this on a Busso group's facebook page, and thought it might be of interest to Anth73.

Not cheap at 300 Euros though.

ECU for Alfa V6 12V AR16101 Phase 1

Worked flawlessly until expansion. Immobilizer can be deactivated.
€ 300 shipping with DHL and tracking
No photo description available.

www.facebook.com/photo.php?fbid=2802992319798665&set=gm.2791530207568872&type=3&eid=ARDqyuWu2mmbGonf_35N4BBXodsAcI0tamOT4Izfp-OV8QCGsJQh9oQwY5kSIUA44HgYjUTMBS7Z767p

[festy]

- The 75 and 75 Potenziata used Motronic ECU 0.261.200.141 with one of two possible chipsets, 1.267.355.737 (9AE3) used mainly in standard 75's and 1.267.356.097 (BF43) used mainly in Potenziata's. I understand the 097 chip can be tuned for higher octane fuel by grounding pin 11. This chipset is likely going to be impossible to find now given the limited number of 75 Potenziata's sold here.

Getting hold of whichever chip you prefer is not a problem, and negligible cost. PM me if you go ahead with the Motronic conversion, I know a bit about these systems.

- The 164 used two versions of Motronic ECU, either 0.261.200.117 or 0.261.200.130. I don't know the differences between these ECU's. I gather with the number of unloved 164's around that eihter of these ECUs will be far easier to source.

The 164 ECUs are effectively the same as the Potenziata/SZ ECU, but from memory the one difference is that the 164 ECUs support an IAC whereas the 75s don't. The 75 chip works fine in the 164 ECUs, but I would expect IAC related DTCs running a 164 chip in a 75 ECU.

[alfahaze]

I would stick with L-jet on the V6. On the 4 cylinder Motronics Alfa used an Idle Control Valve, but on the V6, for some reason the Idle speed is set by varying the ignition advance. Having driven many miles in GTV6 and 75 3.0 with both systems, I can tell you they drive exactly the same, except for one tiny issue, you are more likely to stall the motronic 3.0 when pulling away from lights. I can only assume this is due to where the ignition advance happens to be when you start to move. I think the 164 V6 has the ICV, so that would be the way to go.