1 or 2 O2 sensors for a V8 using MSII

SuperV8 · Post by **SuperV8** » Mon Aug 09, 2010 3:58 pm

I'm using MSII extra for my 4.6RV8. Currently have one WBO2 sensor in the nearside exhaust.

Is there any performance advantage using 2, one left and one right? Or would it be more for fault detecting?

Tom.

kiwicar · Post by **kiwicar** » Mon Aug 09, 2010 4:15 pm

Hi
If you have the cylinders as split banks on the injection then you could tune and log both banks using the the two seperate sensors. How much advanage that is is another matter.
Best regards
Mike

SuperV8 · Post by **SuperV8** » Wed Aug 11, 2010 11:43 am

Thanks, that's what I thought. MSII will take two WBO2 signals input but I don't think it would use two different fuel maps for each bank?

For now i'll continue with 1 and maybe look into it when more funds are available

Tom.

kiwicar · Post by **kiwicar** » Wed Aug 11, 2010 12:25 pm

Hi
I don't know the state of tune of your engine, but to get any gains I would recon you would be looking at 20 to 30 hours on a rolling road developing the maps, I can think of easier ways of gaining 5 to10 BHP for an outlay of a eight to twelve hundred quid. If you are running production saloons then it might be worth it but on a rover??

Best regards
Mike

daxtojeiro · Post by **daxtojeiro** » Thu Aug 12, 2010 1:02 pm

This is a common question I get asked a lot. The answer I always give is theres no point in running 2 lambda's over 1, as you need 8 lambdas or 8 EGT probes.

The problem with one is that the O2 sensor averages all the cylinders it gets fed from, so if one is leaner than the other 3 (on one bank) then you will have richened up 3 to compensate for the lean one. The same can be said if you compare the 2 banks, one of the other cylinders could be richer than the others and youll think that the whole bank is different and adjust all 4 on that side. Before you know it youll have what you think is a perfect setup when all your doing is compensating for the odd bad cylinder.

The answer is fit one and swap them over from each bank, if you find any issues then you will need to check the injector flow rates then start EGT tuning using something like an MS3 that runs sequential fueling.

I've just done all this and its not the easiest thing in the world to do, and to be honest, it didnt make any difference that I can notice as far as power goes, just a little smoother at idle.

So to conclude, Id recommend you stick with one and dont worry

Phil

SuperV8 · Post by **SuperV8** » Fri Aug 13, 2010 11:37 am

Thanks Phil, perfect answer. Well anything that saves me money is perfect...

Tom.