How to get RPM on BMW E30 M42 DIS.

General Q&A specific to RaceCapture/Pro. For app related questions post in the RaceCapture App forum. also see the <a href="http://www.autosportlabs.net/RaceCapture">RaceCapture Information Page</a>

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sbarton
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Post by sbarton »

I'm assunming the brake light switch 'sensor' is safe to connect to one of the Analog Input 1-7? I think it may be 12v so not sure of that would hurt the race capture. Also I just want it to be on/off. How would I set up and configure that?

-Scott
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brentp
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Post by brentp »

It would work on an analog input channel, but I'd recommend hooking it up to one of the digital i/o channels and save the analog channel for something else in the future. The default jumper setting configuration should be set as input, so you should be good to go there. Configure the channel name and a sample rate, and you should be good to go!
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sbarton
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Post by sbarton »

Brian, can you give me the color wires and wire numbers for the back of the gauge cluster for Water Temp, Fuel Level, and RPM?

-Scott
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TrackRat
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Post by TrackRat »

An easy place to grab the RPM is on the negative lead on the ign coil - the DME pulses the negative to fire the coil. I use this on other systems and it works fine. It's also really easy to get to!
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Post by brentp »

Warning: This negative lead connected to the ignition coil has a 500v voltage spike that RaceCapture/Pro isn't designed to handle.

Additionally, the signal is very noisy and would not provide a good RPM signal without proper conditioning.

We are working to release a small adapter board that can safely interface this coil signal to RaceCapture/Pro's pulse input. The technical information can be found here:
https://github.com/autosportlabs/coilx
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TrackRat
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Post by TrackRat »

brentp wrote:Warning: This negative lead connected to the ignition coil has a 500v voltage spike that RaceCapture/Pro isn't designed to handle.
...
We are working to release a small adapter board that can safely interface this coil signal to RaceCapture/Pro's pulse input. The technical information can be found here:
https://github.com/autosportlabs/coilx
Good to know - thanks.
Shawn Waggoner
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Lake Worth, FL
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blalor
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Post by blalor »

brentp wrote:Warning: This negative lead connected to the ignition coil has a 500v voltage spike that RaceCapture/Pro isn't designed to handle.
*zzzzzzap!*
Brian Lalor
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blalor
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Post by blalor »

sbarton wrote:Brian, can you give me the color wires and wire numbers for the back of the gauge cluster for Water Temp, Fuel Level, and RPM?
coolant temp -- br/vi; pin 26 on C1 and pin 4 on C101
fuel level -- br/gn; pin 4 on C2
engine speed -- bk; pin 7 on C1
Brian Lalor
Autosport Labs

sbarton
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Post by sbarton »

Hey Brian,
Can you give me the scaling values for fuel and coolant on your E30?

-Scott
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TrackRat
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Post by TrackRat »

sbarton wrote:Hey Brian,
Can you give me the scaling values for fuel and coolant on your E30?

-Scott
Yes, about to do an install on an E30 - that would most helpful!
Shawn Waggoner
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Lake Worth, FL
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sbarton
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Post by sbarton »

For fuel, Brian's settings was close but not great. So I removed my fuel sender from the tank and with it still plugged in I read the value at 0, and then flipped it over to get the reading at full.
My values:
0.55V=100%
2.9v=50% (Filled car up till my fuel gauge read ~1/2)
4.3v=0%

I did this with a battery tender on so you get similar readings to when car is running at high RPM (alternator full charging).


FYI, Brian's settings were:
0.50v=100%
1.25v=75%
2.0V=50%
2.75v=25%
3.5v=0%


-Scott
Last edited by sbarton on Tue Aug 20, 2013 6:48 pm, edited 1 time in total.
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barkerdm
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Post by barkerdm »

Has anyone notice that the RaceCapture reads the 200-300rpm higher than the stock gauge? I'm getting my signal off the back of the cluster. I also have firmware 1.1.13.

Denny

sbarton
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Post by sbarton »

Yep, mine is like that too Denny. Its a known issue and Brent is looking I to it.


http://www.autosportlabs.org/viewtopic. ... 9535#19535
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MichaelDrost
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Post by MichaelDrost »

Hello all,

Just to add a little of my experience: we run e30 325is and the brakepedal has the brakelight trigger at the top of the pedal. This sends the 12v to the rear brakelights. What we've done, is to tap of the positive, back to our logger (for obvious reasons), but along the way split it off to a led, positioned in full view of the onboard cam (Go Pro mostly). Now my post race process is to take the onboard video, the collected data and mate it, using DashWare.

Synchronising video and data is done in seconds that way and as an added benefit, I always have a graph on screen that shows the brake signal graphed against time. This helps me helping the driver get to grips with braking points and such, because you can see the spike approach in the graph, without having to go back and forth in the video. The graph trick also helps spotting patterns, while reviewing onboards (current kit is Race Logic Driftbox w/ input module and GoPro Hero2 and kit to include RCP as soon as possible).

Hope this helps!

Michael

sbarton
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Post by sbarton »

Matt D. wrote:Awesome information, by the way. I've just installed RC/P into our E36 328i and have been pouring over the wiring diagrams for a week. I looked at the fuel gauge plug first because it seemed the most simple, and what was said up above concerning the E30 is exactly how the E36 looks.

I'll start an E36 thread in the next week or two to share what I find.
Hey Matt, any update on your E36 install?
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