Ideal tool for A/F Mixture Monitoring
 

OK, we've had many discussions here about using O2 sensors and other ways of monitoring A/F mixture for tuning. I just saw a great device on "Two Guy's Garage" on SPEED, the Innovate LM-1 Digital A/F Meter:

http://www.innovatemotorsports.com/

This device uses a Bosch wideband O2 sensor, can handle 5 inputs (e.g. rpm, sensors, etc.), and has 44 minutes of memory at 12 samples/sec, with full playback on your PC. Cost from the manufacturer is $349.

They used the tool on the show to analyze a lean mixture condition problem with a supercharged car they were working on, the graphs looked great and the data clean.

It would be interesting to see if you could somehow connect one of these G-Tech Pros to it to have hp vs. rpm info as well as A/F ratio information throughout the rev range.

You could connect the data at review time by time synchronizing it. The combination of the two instruments would be nearly equivalent to having your own dyno and gas analyzer (though you only get effective CO).

Mentioned before, on this and other boards. The Innovate also does time, I believe, so with time, rpm, and the known gearing of the car, you can calculate speed over time, so actual at the road HP is only one equation away. Compensate for any other factors (aero, rolling resistance, etc) you care to for better accuracy. No need for the G-tech doodad at all.

I'd not be at all surprised if the Innovate PC software doesn't already take advantage of this, and if it doesn't, then it needs to be suggested to them.

You're right, I missed your reference to it in the other thread we just had, or I simply didn't go and look at what you were talking about. Have you actually used one of these units?

Hi,

The LM-1 is available through Pelican.
I work for innovate and am the inventor of the LM-1.

Regarding accell. logging:

I am working right now on the final stages of completing our Auxbox. This box plugs into the LM-1 and adds the following capability:

1. RPM logging
2. Dwell/Injector timing log (built-in sensing)
3. EGT/CHT logging (built-in Thermocouple amp)
4. MAP logging (built-in MAP sensor to 2.5 bar absolute)
5. Acceleration logging (up to 1.5 g, variable range).

For each of the inputs you have a choice to use external signals from other sensors or the internal sensor equivalent.
You can also switch each input to Thermocouple sensitivity for multiple external type K-Tk's.

HP/Torque calculations will be built-in in our Logger software (called LogWorks), incl. possibly calculations for aero and friction compensation.

A beta version of LogWorks (incl. sample log) can be downloaded at:


LogWorks Download

Regards,
Klaus

Cool! Do you own a 914?

I'm not sure (as in I don't know) how accurate Lapuwali's method to calculate speed, distance and hp using gearing and rpm is but if you can measure acceleration accurately at say, every 0.0025 seconds, then the math (Simpson's Rule) to numerically integrate the acceleration values to calculate speed, distance and hp is simple and very accurate. I wrote such a program a few years ago.

What would the max time be for recording? Could it be for a 30 minute race session and then download to a laptop for analysis while comparing the time line to a video playback? That way I could see what the engine was doing during shifts, turns, braking, etc. Looks like a good christmas present for me.........

John: OT...do you have any wide 4 lug wheels for saale or? PM me, thanks

Is there a way to calculate CO% based on AFR or vice versa?

There's a chart rattling around that shows the relationships between HC, CO, O2, NOx, and AFR. However, while the chart shows general trends, I believe they're all semi-independent, so you can't get exact measurements.

CO falls as mixture goes from too rich to stoich, but I can't remember now if it rises on the lean side of stoich, levels out, or keeps falling. As I recall, 3% is very roughly 13:1.

If you have gearing and RPM, you have speed, within the limitations of how accurately you can measure RPM and things like wheelspin and tire growth.

As for "very accurately" calculating HP, you can certainly get a number, and you can even get a reasonably consistent number, useful enough for tuning and knowing if you're gaining or losing power with tuning changes. Getting within 1% has you beating most dynos. There are significant limitations in this method, however, that mean you shouldn't get too hung up on high accuracy, however. Aero effects, for example, will make it appear you're losing power even though you're not. Simply pulling up (or going down) a slight incline will affect the numbers (and would affect numbers with a one-axis acceleration system, too, like the G-Tech).

No, but another VW-Porsche (Porsche Habanero ;)
It's a 68 Westfalia Camper with an 81 3.0 911 SC motor which I am in the process of converting to EFI and possibly turbo.

The LM-1 records 6 channels of data at 10 bit resolution each at ~12 times/second for up to 44 minutes internally for later download to a PC.

Regards,
Klaus

Habanero? Schweet! Another friend of mine had a 2.2L MFI'd (I think) 911E (I think!) motor in his Bus. He called it the "911 Avant", in reference to the various Audi wagons. (He's an Audi-phile, too.)

--DD

Oh, I forgot to mention:

I also own one of the fastest accelerating (zero to top speed < 2.2sec) production Porsches ever produced.

Regards,
Klaus

The Bosch emissions tech guide:

http://www.wrenchead.ca/pub/Bosch-Emissions.pdf

...shows the CO - AFM relationship on 12th page (page 10). Past stoich, it drops rapidly and does not increase.

Among other useful topics, this guide has some very good descriptions of how various types of lambda sensors work, and their limitations.

Whoa, lots of good information in there. I'm going to print the entire document. Thanks for pointing it out.

Hmm, a couple guesses on this one!!

Porsche Junior (the Diesel tractor)
Porsche Design apparel of some sort--did they make running shoes?

...I think the bikes take longer than that to accelerate to their top speed.

--DD

Bingo, you win!!! :D

Drive-wheel hp is easy enough to calculate from the car's mass, speed and acceleration but how do you calculate the torque? Do you use the equation

torque = hp*5252/rpm ?