MRC Tuning no longer tuning 5 Cyl 20v Turbo engines... who to go to?

[prj]

ABY/AAN/ADU, excluding AAN 551A ecu, all others are OK.

[newsh]

ABY/AAN/ADU, excluding AAN 551A ecu, all others are OK.

Why not 551A?

[prj]

Why not 551A?

Only AAN 551A is not supported. ABY 551A is fine.

Why not? Because it has a 87C64 and not a 87C257. I think it is possible to solder a couple wires to convert, but I don't own any AAN 551A ecu's to check.

[newsh]

Only AAN 551A is not supported. ABY 551A is fine.



Why not? Because it has a 87C64 and not a 87C257. I think it is possible to solder a couple wires to convert, but I don't own any AAN 551A ecu's to check.

Ah ok, my ECU is a 895-907-551-A
So an ABY unit [emoji106]

[Error404]

Ready and waiting

[kj6304]

MRC Tuning no longer tuning 5 Cyl 20V

Ah ok, my ECU is a 895-907-551-A
So an ABY unit [emoji106]

Now I am worried and wondering if my 1994 URs4 US version AAN ECU is supported or not by PRJ? As per the following quote from Quattroworld with reference to PRJ.
Have to pull the ECU and check the part# against this list.
BC

Quote:
Nov, 2009.
Our C4 UrS-cars have an AAN engine that is controlled by a Bosch Motronic ECU (computer). This AAN Motronic ECU has had a number of part numbers, depending on the location and year. Here is a list compiled by Dmitri ("prj") on the S2Forum (who has cracked most of the Motronic codes)

"AAN Motronic ECU Part Numbers:
551A early UrS4 with pseudo dizzy and 8k boost chip
551AA UrS4 non-immo, Europe and America
551B UrS4 same as 551AA, but auto
551C UrS6 incorporates all software updates from RS2, different codebase, more diagnostics
551D UrS6 same as 551C but auto (see photos at the end of this post)
551E UrS6 has a small tweak to fuel on cold start
551F UrS6 same as 551E but auto.

Unquote.

[prj]

1994 is supported for sure, the 551a was fitted until MY1992 on urS4.

Most likely it is possible to convert them, I just never looked into it.
Realistically on the 87c257 A14 is just wired high, so it works like a 87c128 (which does not exist).

I think the only difference between those two ECU's is one trace on the PCB - A13. Probably have to solder one wire and cut a single trace for it to take the later chip.

---

Andy (Sonic) pointed me to one of his friends who has experience with embedded, and he gave me some good ideas.
I ordered a dev board for a newer style ARM MCU - going to test if it is fast enough to emulate the 27c512 with just the one micro. The 80C535 MCU's are clocked at 12mhz and machine cycles are at 1/12 that, so 1mhz. It fetches two bytes from the ROM per machine cycle, and the timing is 1/6th of a machine cycle, So I have to hit a target latency of max. 166ns. I think in a tight loop it is possible to hit approx. 60-100ns on the ARM.

If that turns out to be the case, it will be possible to real time map. It will also significantly decrease the complexity of the system, as only 3 chips will be required for the entire thing to work.

[kj6304]

MRC Tuning no longer tuning 5 Cyl 20V

Thank you Sir and now seeing the light at the end of the tunnel. Rock on.

[AquaS2]

Has there been any more progress on this?

[prj]

Unfortunately not. I made an initial board layout and that's where it is, due to just having to devote too much time to my business.
Because I do not really tune these cars anymore (there are so few) and I fit standalone ECU's on them most of the time because it saves time, I will probably release all the info to the public once I get time for it.

I am not making any money off it anymore, so it makes no sense to keep it under wraps.

[Error404]

Hey Dmitri, glad you are still lurking here
You should let someone in the UK have your 2.3.2 toolbox and then take a commission on a tune
I am sure there are still a few bucks to squeeze out of your hard work

[prj]

I don't think it's commercially viable at this point - can just release it out to the wild.

[macspring]

Dmitri, what stand-alone ECU(s) do you like to use ? Just curious.

Thanks.

[prj]

From the cheaper end of the scale - My company is the regional dealer for the Ecumaster brand.
The Ecumaster Classic costs 690 EUR and it can run everything in the engine without issues, incl. the stock trigger setup.
A PnP adapter is available, and that costs an extra 135 EUR. Using that the ECU plugs into the stock connectors.

From the higher end of the scale, we are also dealers for Autronic and Link.

[Greg_S]

Prj what is the difference between them? I assume the higher end ones have more mapping points, faster bus speeds etc?