Plans for 4 Channel O2 WB expansion board?Plans for 4 Channe

If you have ideas for a new board, for new features for existing boards, or want to suggest new applications for the I/O Extender, this is the place to post.

Plans for 4 Channel O2 WB expansion board?Plans for 4 Channe

Postby mill383 » Mon Sep 01, 2014 1:00 pm

The US Nationals are in town this weekend. I made it out there for an evening and enjoyed walking around the sportsman pits, looking over all the different setups. I notice quite a few of them have ditched their multi-channel EGT systems for multi-channel O2 wide bands. Speaking to one of these races, I noticed he was still running a carberator, but supposedly he was somehow able to adjust fuel mixture between cylinders. Regardless, he was using "RacePack" as the data acquisition system, and a "tip" he gave me was that he buys the Bosch O2 sensors from Napa, bypassing the mark-up that the Wideband aftermarket folks add on.

This got me thinking how one could more cost effectively add multi-channel WB O2 to MegaSquirt. On my MS3Pro drag car project I'm using one NGK Wide Band Powerdex AFX controller and doing a quick ebay search, it now costs around $320 (I think the price has gone up over the last couple of years?). The LC2 from Innovate is around $200 per sensor/ controller. I really like their minimalistic design (ie no display, small signal conditioner), but to do 8 channels it would get pretty expensive.

I really like your EGT-CAN unit and have one on my car. The only change I would make would be a smaller 4-channel unit that could fit into a very small aluminum Bud box, similar to what Top Fuel cars do.

So along those lines, it would be pretty slick to make a 4-channel O2 WB controller that directly reads the Bosch O2 sensor(s), conditions the signal, and spits it out on CAN for interface to MS products. One unit would satisfy the 4-cylinder crowd, while the V8 crowd would buy two units. I personally think left bank, right bank units install more neatly on V8s anyways, assuming the units could handle underhood temperatures.

Just putting this out there to see if there is any interest and/or consideration of such a product.

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Re: Plans for 4 Channel O2 WB expansion board?Plans for 4 Ch

Postby jbelanger » Mon Sep 01, 2014 1:05 pm

It is something I am considering. I already have an add-on board that can be used with the IOx that can have up to 8 SLC-OEMs (from 14point7):


I do need to do a few tests but this one could be a stand alone version with a TinyIOx (the picture shows an early version which is slightly different).

I was thinking of having a 4 channel version that would fit in the small waterproof Cinch ME case (same one I used for my rugged ECU). That has definite advantages for those who need a sealed box but it does add cost and possibly is a bit larger than a simple non-sealed aluminum box. But in either case, the electronics is not rated for automotive temperatures so it would still to be put away from heat sources (but could still be underhood for the sealed unit as long as it's kept under 85C or 185F).

I'm interested in your opinion and anyone else's. That could help me decide which way to go.

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Re: Plans for 4 Channel O2 WB expansion board?Plans for 4 Ch

Postby mill383 » Mon Sep 01, 2014 3:11 pm

I see. 14point7 is the ticket. Pretty neat. All that is needed is a back-plane board to stitch it all together with a TinyIOx squirting it over CAN, and packaging. I would think most folks that are reading these forums have these skills.

Well, no rush from my perspective. I'm locked in with my 8-ch EGT setup. I need to focus on getting the car done and back to the track and start tuning. My main interest is to resume cylinder balance testing on my LT1 engine. 20 years ago I had a homemade 8-ch EGT data logging system (DOS based) which showed me the back 4 cylinders were running cooler (richer) than the front 4. Am wanting to repeat those tests with this new EGT-CAN setup, and then modify individual cylinder fueling with MS3 to optimize things.

No real plans for me to convert to 8 ch WB any time soon. It was just a fun mind exercise.

If you do decide to package something, my vote would be for a 4-channel system, for the reasons I mentioned earlier. It's friendly for the 4-bangers and bikers, and the V8 crowd would just need to buy 2 units.

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Re: Plans for 4 Channel O2 WB expansion board?Plans for 4 Ch

Postby Rod S » Wed Sep 03, 2014 6:27 am

jbelanger wrote:I'm interested in your opinion and anyone else's. That could help me decide which way to go.

OK Jean, my thoughts.

First, for Dave's benefit, as Jean knows I now use the 14point7 SLC-OEM modules on my own carrier PCB (which takes up to four of them) and sits in a standard metric case (like the full size IOx case but I use a slightly longer one) next to another carrier PCB with an IOx-OEM and all the other I/O circuits I need.

So, thoughts.....

Case - plain, like the IOx etc. 95% of end users will have it in a non-aggresive environment and the 5% who don't will figure out their own way of sealing it. Lets face it, all of the mainstream MegaSquirt products remain in un-sealed cases with computer style DB connectors, only the more expensive models use OEM automotive type cases and connectors.

4 vs 8 - 4 is plenty IMO. 4 is obviously going to be more cost effective for those who only want 4 but if the boards were made modular so that two could be stacked in a short tall case or connected end to end in a longer shallow case then presumably you could omit the tiny IOx chip on the second board (just use I2C inside the case) to keep costs down for those who want 8 and don't mind them all being in the same box (rather than two boxes one each side of the engine) ?
But otherwise, two boxes, individual IOx chips and presumably just two different CAN IDs.

Other thoughts -
For a non-sealed case, stick wth the molex 6 pins connectors for the LSUs so the connections match Alan's stuff, your other board, and, strangely co-incidentally, my home made one, so cables are interchangeable.

For either case option, add some additonal pins on the connector(s) and take them to a proto area (as much as room will allow) and provide access to some of the other Tiny IOx pins for the DIYers who might want to use some of the other IOx's potential.

Rod S
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Re: Plans for 4 Channel O2 WB expansion board?Plans for 4 Ch

Postby tpsretard » Sat Sep 06, 2014 7:10 am

Just thinking out loud here. But i think 75% or maybe more installs are 4 cylinder engines. A board with 4 egt's and 4 lambda's all integrated. I can think ofn2 cars i would uses this on right now.

Might be a seller, not sure just tossing the idea out there.
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