"Technology for Tuners" Newsletter #6

This is Innovate Motorsports' "Technology for Tuners" Newsletter, Issue #6. These updates are intended to keep you informed of LM-1 tuning tips, firmware updates, application notes, new product releases, company news, and other useful information. In this issue:

1) LM-1 Firmware version 1.41 is released
2) New products: Carrying Case, Window Clamp, and Autronics Cable
3) Visit us at the PRI show
4) Testimonial T-shirt contest
5) LC-1 & XD-1 update
6) Tuning Tip- Ethanol content

LM-1 Firmware version 1.41 is released

This firmware update for the LM-1 fixes a random and rare bug that produces momentary lean spikes/glitches. If you’ve seen lean glitches in you log files, and you know that you aren’t experiencing missed ignition events, definitely install this firmware update.

New products: Carrying Case, Window Clamp, and Autronics Cable

The MTS (Modular Tuning System) Carrying Case is a durable plastic case, designed to hold the LM-1 and all accessories included in any configuration of the MTS kits. The Window Mount allows you to have the LM-1 mounted to your windshield. This will help provide a better view of the display while road tuning.

To better interface with Autronics’ ECUs, we’ve developed a custom interface cable. This is essentially a modified analog output cable that includes some active circuitry to precisely match the input expectations of the ECU. The SKU is #3745, and it’s available on our web site for $59.

Visit us at the PRI show


The PRI show in Indianapolis is part 2 of the annual show madness. We’ll be at booth #5214, showing off the new products, playing the new training videos, and meeting customers. If you’re coming to the show, drop by and say hi to Klaus, Cort, and Patrick.

Tuning Story Contest

Write a quick testimonial, take a cool photo (you and an Innovate product in use), and send it in to us (email or snail mail). Each month we’ll select the best ones, and send the winners some Innovate swag- long-sleeve T-shirts, hats, Polo shirts, etc. And you might even see yourself in a national magazine ad.

LC-1 & XD-1 update

The much anticipated LC-1 (aka “Lambda Cable”) beta units are scheduled to ship in the coming weeks, with full product release in January. But, as usual, until full release, we can't commit ship dates. The XD-1 Digital Universal Gauge (also much anticipated) is tracking basically the same. All of the new products will be in full production well in advance of the 2005 race season.

Tuning Tip: Ethanol Content

We've had a few reports where users could not “nail down” their tune on the street with the LM-1. The AFR's would jump about 0.5 AFR across the WOT band even in the same weather conditions in the space of a few days. Instead of holding a tune, the engine seemed to slowly “yodel.”

Naturally the first thing to blame was the LM-1. But it turned out that the users filled up at different gas stations, sometimes filling up on gas that had 10% ethanol mixed in. As expected, when Schnapps is mixed with cars, things get a little complicated.

If ethanol (stoich AFR of 9) is mixed with gasoline (stoich AFR of 14.7) the resulting gas has a lower stoich AFR than 'pure' gasoline. As the fuel injection is tuned to mix a certain amount of fuel for a given amount of air, the resulting mixture would be leaner when using a fuel with lower stoich AFR.

This can be calculated:

sAFR = (%ofAdditive * sAFRadditive + (90-%ofAdditive) * sAFRgas) /100

where:
sAFR is resulting stoich AFR
%ofAdditive is amount in % of mass of additive (ethanol) mixed in
sAFRadditive is stoich AFR of additive (9 for ethanol)
sAFRgas is stoich AFR of base gasoline (14.7)

For a 10% mixture of ethanol to gasoline by mass the resulting stoich AFR is 14.13

So, for an engine that's tuned to certain AFR at a certain load and RPM on straight gas, the resulting (gasoline equivalent) AFR when running the mixture can be calculated as:

new AFR = tuned gas AFR * (gasoline stoich ratio) / blend stoich ratio

An engine tuned to 12.5 gas AFR will run at the equivalent of 13 gas AFR with a 10% ethanol blend. This is what these people were seeing.

Of course, when running in closed loop, the engine will run at 14.13 AFR instead of 14.7. O2 sensors (incl. widebands) don’t measure AFR, but Lambda. Lambda is defined as actual AFR/stoich AFR. It's a ratio. In closed loop part throttle the engine is just running at Lambda 1.0, regardless of fuel. The same would be true for other Lambda values when running closed loop at WOT using a wideband. The engine would run at the tuned Lambda and everything would be fine. Open loop systems would need to be retuned for alcohol blends though.

Until next time... Keep On Tuning!

-Innovate Motorsports

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