'88 325is M30 street car-->S54 -->S50 -->M54 Enduro Race car

[matthugie]

For the tach I think you might be able to use the e30 M3 tach with a 6 cylinder coding plug, but I'm not 100% sure on that. I'd go with a Stack or AIM unit, but I'm also biased because I want one pretty badly.

[Jb325is]

I'll look into the e30 m3 cluster, but I'm not into paying stupid prices for m3 stuff, and $300-400 for a stock cluster seems a bit stupid. The Race Technology dash is $900 I think, and is programmable to most sensors. It's not quite as nice as the AIM but it's not far off. AIM is $1200 and up, STACK is $1300 and up. I'm more inclined to go in this direction because I don't care about the stock look.

I'm not sure on the headers. I know that the Kromer Krafts were going to require a small notch on the subframe, sway bar mount spacers, and THR control arm mounts (I already have these). I doubt these will require that much work, but we'll see.

[nando]

the stock tach will work, but it will sweep past the end of the tach at the S54's redline.

you can just print a new face using the M3's pattern, and swap in a different coding plug. the M20 coding plug won't work. the tachs are physically identical.

I bet those aftermarket gauge panels support CAN which is nice because you can hook that right up to the DME to get all the data directly without extra wires or signals.

[Jb325is]

the stock tach will work, but it will sweep past the end of the tach at the S54's redline.

you can just print a new face using the M3's pattern, and swap in a different coding plug. the M20 coding plug won't work. the tachs are physically identical.

I bet those aftermarket gauge panels support CAN which is nice because you can hook that right up to the DME to get all the data directly without extra wires or signals.

They do, you have to buy a CAN interface adapter thingy, but I think that's only like $150 extra

[FredK]

the stock tach will work, but it will sweep past the end of the tach at the S54's redline.

you can just print a new face using the M3's pattern, and swap in a different coding plug. the M20 coding plug won't work. the tachs are physically identical.

Yup.

You'll need an E28 M5 coding plug, 62111377664. You'll have to remove it from its plastic casing because the E28 housing is shaped differently than the E30 housing.

[nando]

I think I read it was NLA, but there's a euro E28 coding plug that also works?

[FredK]

Oh, I'm not sure. I got one last year.

[gills]

Same coding plug can be used on M cluster?

[gills]

jb, what are you going to do with your intake?

Sent from my SCH-I535 using Tapatalk

[The Dark Side of Will]

the M20 coding plug won't work.

Won't work with the S54 or won't work with the M3 tach?

[FredK]

An M3/8K tach will read incorrectly when used with an M20 coding plug.

[The Dark Side of Will]

An M3/8K tach will read incorrectly when used with an M20 coding plug.

Duh... yeah, the coding plug has to take both the cylinder count and the max RPM into consideration.

[dude8383]

I think I read it was NLA, but there's a euro E28 coding plug that also works?

Yeh, Guten bought the last few. We managed to purchase one as well. I would love to hear about the euro coding plug though...

[nando]

I'd really like to reverse engineer the coding plug, it's likely very simple. But finding a data sheet on the HML 087 is basically impossible. :(

I think its just a 8 bit serial PROM.. But i have no pinout and no idea how to talk to it..

[The Dark Side of Will]

I haven't looked at a BMW coding plug yet, but I've recalibrated GM tachs. Those are just an RC oscillator (change R, C or both to change calibration) and a crystal oscillator as a reference. BMW being BMW, they may have used a timer chip to produce an extra clean calibration signal instead of the raw output of the RC oscillator.

So does the coding plug have an IC, a resistor and a capacitor in it?

Here's an outfit that claims to have a few in stock:

http://www.seekchip.com/icstock-H/HML087.html

However, the link to the .PDF on that page goes to some other chip's datasheet.

http://www.seekdatasheet.com/SearchPartNo.html

There's a surprising amount of static on the google for that part number.