o2 Sensor location - Magasquirt

[slippery]

I bought a PNP Megasquirt for my '87 325is with Bavauto headers and supersprint catback.

I want to install a wideband o2 sensor and I am not sure what the best route is. As I see it, I have three options:

1. Install the o2 in the current location, about 10" after one of the two collectors. I believe this would measure cyl 1-3 only.
2. Install the o2 sensor at the x pipe. Given how far back the header collectors are, the x pipe ended up closer to the rear wheel, where the door ends.
3. Install two o2 sensors, one on each header collector.

If I do #3, can Megasquirt run two separate o2 sensors?

Any input on this is appreciated.

[Jaxx_]

1 or 3 sounds best to me.

Isn't the msPNP microsquirt based? It can do dual WEGO.

[slippery]

This is what it says on the website:

”The MSPNP Gen2 ECUs are based on MS2 and allow us to offer you a powerful standalone ECU/EMS at an incredibly low price.”

[Reichart12]

What is your exhaust design after the Bav Auto headers, I'm not familiar with Supersprint? I have the same Bav Auto set and right after they turned towards the back of the car, I have them merging into a 2.5'" pipe. It's at this point, I have my wideband for MS2. Basically it's right near where the passenger's feet would be.

[Panici]

My previous M52B28 + MS3X setup was running a stock E30 x-pipe. Decided to run the O2 sensor on one pipe only.
Theoretically if the engine is running correctly and all your fuel injectors/spark plugs are even, there should not be much variation.

Extra cost/effort for dual O2 sensors isn't worth it unless you're in a racecar application. And even then I'd choose to run per-cylinder EGT sensors before I did dual wideband O2s.

[slippery]

What is your exhaust design after the Bav Auto headers, I'm not familiar with Supersprint? I have the same Bav Auto set and right after they turned towards the back of the car, I have them merging into a 2.5'" pipe. It's at this point, I have my wideband for MS2. Basically it's right near where the passenger's feet would be.

Sorry about the late reply. I was able to take a couple of -crappy- pictures last night. See next post

I think after reading the comments in the thread, I can just use the current location with a single O2 for now and go from there.

[slippery]

[digger]

A single o2 in collector will be fine as will it in the x pipe

[Austrianvespaguy]

Option 1 is just fine. It's far enough away from the ports it won't overheat and will give you a good mix of those 3 cylinders, which is plenty good enough. Really, you pretty much only need/use the wideband for tuning anyway. Get you VE dialed in nicely, do NOT use closed-loop EGO feedback (as doing so will invariably cause your car to run poorly in the event the sensor fails, which they do), and then after that you only need it if something 'changes' and then you can reference it to help figure out what's going on. But after you've got your tune dialed in, it's pretty superfluous, hence why an average of 3 cylinders is just fine.

[digger]

Option 1 is just fine. It's far enough away from the ports it won't overheat and will give you a good mix of those 3 cylinders, which is plenty good enough. Really, you pretty much only need/use the wideband for tuning anyway. Get you VE dialed in nicely, do NOT use closed-loop EGO feedback (as doing so will invariably cause your car to run poorly in the event the sensor fails, which they do), and then after that you only need it if something 'changes' and then you can reference it to help figure out what's going on. But after you've got your tune dialed in, it's pretty superfluous, hence why an average of 3 cylinders is just fine.

there are ways to cope with a failed sensor surely MS has the means. ive been running open loop WB for the last 15years as current ECU doesnt have this feature and while it works in open loop it isnt as precise to rely on normal corrections to get it to run as best it can. I would not hesitate to use closed loop WB if available. I do prefer NGK NTK sensors though