e30 m3 tach converter

[atomic]

What exactly does this do since this thread is based over a year period and with a ton of confusing statements along with the videos.... Is that all this does is sweep the tach needle at start up and a test mode at 500rpm increments ?? Please clarify Thanks

[Jason89i]

i just sold the m3 4 days ago......but i will probabily buy one for backup.

the tach converter is very simple.

problem: the 6 cylinder motors (m50, s50) have a different tach signal that gets sent to the cluster. you can use the e30 325 cluster and everything will work fine. BUT.....if you put a 6cyl into an e30 m3 or 318 (originally a 4 cyl), the tach will be off. for the 318 its an easy fix. just pop in a coding plug from a 325. the 318 and 325's have the same tachometer, just different coding plugs. HOWEVER......the e30 m3 has a different faceplate .... so the coding plug trick will still not be accurate. so, you need rev's little signal converter to get the 6cyl engine to work with the stock e30m3 cluster.

cheers, jason

[ericzz]

Or just install a 6 cylinder plug and tach face and be done .

[Jason89i]

Or just install a 6 cylinder plug and tach face and be done .

correct. but for those with euro motors.....the 8k tach is useful. cheers, jason

[atomic]

Or just install a 6 cylinder plug and tach face and be done .

Yeah this is what I did but I am only running a m20 so I kinda figured this was more for the s50/52 (or euro) swaps that would have a higher rpm redline than the m20.

Looks like a great product for those who need one....I subscribed just in case down the road I end up with a s50/52 motor

[87-325ic]

great work. like to see some techno savvy individuals out here.

mpg rate gets a pulsed / length signal from the injectors. with the 3.2 and 24# injectors.....obc says 84mpg = 24.5 mpg actual.

to calculate actual speed vs. speedo readout is quite simple. set cruse on the intersate (lets say at 70) then use your obc timer to find exactly how long (in seconds) it takes to go 1 mile (use the milemarkers for exact reference.) cliffnotes for the math challenged.......take 3600 divided by the seconds (lets say 54.9s) and viola.....your going exactly 65.93mph. to get a more accurate reading take 7200 divided by the time (109.8s) it takes you to go exactly 2 miles.

ive used a combination of speedo readout, police road-side radar signs, the OBC, and GPS to calculate the error in my e30.