Mega Squirt - How does it work?

[Ian Anderson]

Ok so if I was to fit megasquirt to the RV8 in the GT40 I would need O2 sensors / lambda sensors to be connected to sniff the exhaust gasses and make corrections by telling the ECu what it needs

With MS I believe it batch fires each set of injectors on each bank of cylinders

So now presuming 2 O2 sensors need to be used and presuming each sensor tells that side how much fuel is needed????

Now this is where I need help
My exhaust is a 180 degree crossover system with numbers 3& 3 from each side crossing over to the other bank at the collectors making it fire down alternate exhaust pipes.

So if I have an O2 sensor in the collector which bank will it control? As that collector will have 2 from each bank

Hopefully I will be kicked around the head a few times to enable me to get this thick skull around this bit

Thanks in advance

Ian

[ChrisJC]

I'm no expert on Megasquirt, but I would have thought that if you 'cross-wired' the injectors in the same pattern that you have 'cross-plumbed' the exhausts, then everything would be fine.

Chris.

[ian.stewart]

The batch fire in reality does not make that much of a difference, the pulse widths and amount of pulses would not allow the Lambda to dectect any difference, I only run one lambda for setting up, certainly the lambda would not see aything fast enough to have an issue with batch firing, but, Sequential is great, but expensive as you need more drivers to run the injectors, but in reality you make very, if any power from sequential firing if any, only a marginally better emmision figure
Ian

[kiwicar]

Hi Ian
"Standard" MS is meant to work with a single lambda sensor, although it batch fires on alternate banks it does not change the the fueling between banks (or at least it didn't when I was last looking at it 12 months ago) With your cross over manifolds you will be sampling off both banks so the set up should be ideal. I think there is a MS extra mod for 2 sensors but the cross wiring of injectors Chris sugests would sort that out if you want to go to two sensors. personally I would start with 1
Mike

[bill shurvinton]

As they said. Keep it simple on your first install. When you get to doing it for the second time you will know if certain of the fineries matter to you or not.

[Eliot]

Indeed. Std MS only uses 1 lambda. You can fit two so it corrects each bank independantly. Not many people use it, although my friend Matt has dual widebands in his 5L tvr with MS2 - which shows a slight difference between banks - but only a few % - and you have to wonder if thats down to the sensors themselves.

No harm in fitting a bosses in each collector (i have) but one is just fine to get started on.