Question on Innovate inductive RPM Clamp

May 21, 2009 | 11:36 PM

carbonRX8

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Question on Innovate inductive RPM Clamp

I picked up an innovate LMA-3 and am totally smitten by it. Will be using it to run my boost, fuel and AFR gauges as well as record those parameters and 2-axis acceleration, a temp channel and RPM. I will be using the RPM to sync my data logs from the innovate group to my AccessPort logs (My computer will not talk to my AP dongle.)

Any way. Innovate sells an inductve clamp. I am wondering if anyone has run it or can speak from actual experience of one used on an RX8. It is part number 3727. My worry is that, like the crappy pick up on a dyno, I will not have a good signal or worse it just will not work. From the LMA-3 manual

Quote:

The inductive clamp measures the magnetic field created around a spark plug wire when spark
current flows. If a metallic shield covers the spark plug wire, the inductive clamp may not work
because the shield would short out the magnetic field. Like all inductive clamp rpm pickup
devices, some ignition systems like Capacitive Discharge Ignition (CDI) or multi-spark ignition
systems may not work properly with the inductive clamp pickup because the pulses created may
be too short in duration. Multi-spark systems confuse the ignition timing measurement because

the RPM converter cannot distinguish which ignition pulse belongs to which crank rotation

. The

LAM-3 will work only on the tach output of the ignition system in this case.
The inductive clamp must be clamped around ONE lead only. Clamping it (for example)
around all wires of a coil-on-plug pack does not allow it to work because the magnetic

fields of the wires most likely cancel each other out.

It is only $20, so I might ought just buy it and try it out.

Thanks in advance.

May 22, 2009 | 03:28 AM

swoope

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you trailblazer.

cant wait to hear how it works. it would solve lots of problems for many if it works.

beers

Jun 22, 2009 | 10:22 AM

carbonRX8

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Well, it is a little noisy at idle (not sure why) but the inductive clamp sold by innovate works very well with the LMA-3. So now I have an independent measure of RPM.

I have been told that this unit will not last forever in the heat.

I will post a trace or two later this week.

Jun 24, 2009 | 06:48 PM

Joe RX-8

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From: Johns Creek, GA

I would be interested to know how closely you check the readout compared to the tachometer in the instrument cluster. I am installing a Traqmate in my car, and when I used one of the coil ECU lines as my RPM input, the display on the Traqmate was low by about 12.5% (the Traqmate read 8300 RPM at the 9500 RPM redline). On the Traqmate you can set the number of cylinders to adjust this, but I would need to set it to 1.75 to get it to read correctly (and the Traqmate can only accept integers).