EGT monitor on a bike?

[Honclfibr]

I've been poking around the import tuner sites since I got my eclipse, and one thing I noticed is that many of them use an exhaust gas temperature gauge to map out the air/fuel mixture in their cars. Got me wondering if it would be feasible to do this with a bike as well.

I've got a jet kit here that I want to use to cure a flat spot around 7k, and rather than dragging my bike to the dyno and shelling out $$$ to have someone tell me my mixture settings, I was thinking I could set up one of the DAQs we have at work to monitor one of our thermocouple meters hooked into the exhaust output and check out the mixture myself. Figure it'd be handy if I can get engine RPM in there as well.

Has this been done? Is it totally unfeasible on a bike? Just curious...

[TLRMan]

It's been done, but your EGT can vary.
Better just to shove a sniffer up it's ass.....
or do you plan to monitor all the cylinders?

[PinHead]

Originally posted by TLRMan

Better just to shove a sniffer up it's ass.....
?

Just as ya think you know someone

[Honclfibr]

Originally posted by TLRMan
It's been done, but your EGT can vary.
Better just to shove a sniffer up it's ass.....
or do you plan to monitor all the cylinders?

Yeah, I was a bit suspicious about how accurate the EGT would be with the small exhaust flow of a bike cylinder. And I probably don't have the resources or the knowledge to convert exhaust temp into a/f for my specific bike either...

Sniffer sounds good but I don't have one of those, I got thermos coming out the ass

I could monitor all four cylinders, if that would help. It's just another thermo/receiver and a channel on the DAQ, plenty of those.

Not sure how to grab engine RPM though. I could run the coil pack wires into digital inputs, but converting the ignition pulses into RPM would be a bit of a pain in the ass...

[Honclfibr]

Originally posted by Honclfibr
Not sure how to grab engine RPM though. I could run the coil pack wires into digital inputs, but converting the ignition pulses into RPM would be a bit of a pain in the ass...

Actually I take that back, I don't think it would be hard to do at all. It's just 1 / (Time of Current Pulse in ms) - (Time of Last Pulse in ms) * 1000 / 60...A C program to take the digital input and output an RPM channel would take like 15 seconds

But gotta make sure and sample enough not to miss the ignition...so say 13krpm max, that's 216 pulses per second, dunno what the duty cycle of one ignition pulse is gonna be though...10%? That'd be a sample rate of at least 5khz...eh, not so bad with 5 channels, I think it can be done....

Err wait, mebbe I'm going about this the wrong way, what kind of signal does the tach get for engine rpm? *That* would certainly be a lot easier...