The V8 Owners Forum -

I'm running an MS2 V3 on an originally flapper injection 3.5 RV8, at the moment MAP only. I picked up a hotwire AFM from a 3.9 and wondered if if would be suitable to use for MAF or combined MAF/MAP system? And is it worth the effort?

Not worth the effort, stick with Map

katanaman wrote:Not worth the effort, stick with Map

Interesting. There appear to be opposing views here.
It's a road car and I'm interested in economy as well as performance.
I've got the second bit OK...

From all I've understood about EFI, the reason for using a AFM system is that it is resilient to production variations, stick it on any engine and for a given flow through it at X revs it gives you a certain air fuel ratio regardless. So for production engines it is basically fit it on the line, tweek the idle so it runs and it should be consistant, rather than accurate. A Map based system requires a certain amount of tuning and setting up, but having said that it can be tuned far more accuratly to an engine over a wider variation of conditions (depending on sensors) and rather than giving a single air fuel ratio at a given engine speed then modifying it for throttle position etc, it can give several AFRs based on throttle position, revs and manifold depression. Also manifold depression against throttle position is a much better measure of load on the engine than air mass against throttle position as it is indinendent of instantaneous volumetric eficiency. Also you don't have the restriction in the inlet.
Best regards
Mike

DaveEFI wrote:I'm running an MS2 V3 on an originally flapper injection 3.5 RV8, at the moment MAP only. I picked up a hotwire AFM from a 3.9 and wondered if if would be suitable to use for MAF or combined MAF/MAP system? And is it worth the effort?

It can be done using the extra code in MS2. I have done it for a few engines that needed better control than TPS can give, but that had no plenum (2 stroke bike engines, etc) .

Personally I wouldn't think you will gain in economy if thats your worry, but its worth it if you want to have a play with the setup, if you do it let me know how it goes as I have a guy who also wants to use MAF on an RV8,

Phil

daxtojeiro wrote:

DaveEFI wrote:I'm running an MS2 V3 on an originally flapper injection 3.5 RV8, at the moment MAP only. I picked up a hotwire AFM from a 3.9 and wondered if if would be suitable to use for MAF or combined MAF/MAP system? And is it worth the effort?

It can be done using the extra code in MS2. I have done it for a few engines that needed better control than TPS can give, but that had no plenum (2 stroke bike engines, etc) .

Personally I wouldn't think you will gain in economy if thats your worry, but its worth it if you want to have a play with the setup, if you do it let me know how it goes as I have a guy who also wants to use MAF on an RV8,

Phil

Thanks Phil. Coming from the horses mouth says I shouldn't bother.