RPM's not being read correctly?

[bcool]

Alright so i currently have my rev limiter set at 8K RPM and i haven't really gotten into full boost untill yesterday. I noticed something strange though. At 7500RPM in 3Rd gear i should be at 90MPH but when the ECU says im at 8000 RPM i'm only at 70 MPH and i know that i should be pulling some more RPM out of the car. Oh and in 5th gear at the "rev limiter" i'm only hitting 120MPH (my gearing should get me over 150MPH. Now because the engine runs great i'm assuming that all my timing events for the motor are dead on so why am i getting this odd tach signal?

Oh BTW if you haven't noticed by this point if something can go wrong with my VEMS it will happen to me. haha

[rob@vems.co.uk]

What are your datalog's saying about the RPM?

Rob

[bcool]

I havent even got my in-car tach hooked up yet. I'm just reading this of of Megatune and my datalogs say the same story. I'm assuming it may have something to do with how we set up my motor under 6 cylinder configuration.

[rob@vems.co.uk]

Go to Settings->Constants and tell me what the Constant for RPM calc value is.

[bcool]

3000

Here's my msq file for a quick look over if you need it.

http://myweb.cableone.net/mjbless/vems/3rotor.msq

[rob@vems.co.uk]

The calculation is:
rpm constant = 12000/ncyl

rpm constant = 12000/4 = 3000

But you havent got a 4 cylinder - I dont know WHAT you've got with a 2 stroke 3 rotor engine - its either a 3 or 6 cylinder engine:
rpm constant = 12000/3 = 4000
rpm constant = 12000/6 = 2000

Best that you give either one a try and see what the score is.

[Jorgen]

2000 is correct for a 6 cylinder and the 3 rotor would be the same.

You need to strobe the engine!!! For an install like this you should do it at several RPM's and at all rotors.

The command to lock 0deg advance is Manmda01, Manmda50 will lock it at 20 deg timing. Next time you cycle power the ECU will run the ignition advance from the map again.

Jörgen

[bcool]

Got it changed to 2000 and its dead on. Thanks guys, I knew that it was off i wasnt sure which way to set it though. Oh and i'll do the timing light with the timing lock this weekend to verify that everything is kosher.