[Lexc269]

I have been helping a friend on a 363 aluminum heads TF R intake and a hyd roller comp cams cam kit. It is as big of a street cam one could possibly use and expect drivability. Spec 578 lift 245°of [email protected] 0.50 lobe separation is 110° i talked him into purchasing MS 2 on the pretence that i would install it and tune it good enough to take it to a dyno.ive spent a lot of time on it and trying to make sure this firing orfer issue is not a take away power part. I spec a ford letter to cam designed for EfI and as in other things he chose a different cam.
im concerned about his builder spec a cam with the old firing order to pre EFI. My thoughts are ford changed the firing order for a reason and loosing power is just not going to cut it. Leaving fuel setting on a intake valve because it was injected out of time to early or to late is not optimal. Please correct me if my reasoning is wrong. I do not wish to chase in my tail anymore than needed learning curve for the old old school guy is testing my patience.
Next question with a 8 cylinder engine setting in MS2 and a single wide ban 02 sensor does the ms 2 figure the AFR with the asumpttion my other 4 cylinders are the same AFR . (in other words left bank x2) = total engine AFR) or do i need two 02 sensors. Thanks in advanced for the help . Fyi im using the DIY PNP MS2

 

[89LX 5.0]

MS2 is batch fire, not sequential, so its going to inject on the back of a closed valve no big deal.
Yes it assumes the other bank is the same, you can run 2 O2's if you want.

 

[Lexc269]

Thanks for your help, can you or anyone tell me why ford changed the firing order when they started EFI . I am familiar with optional 5, 7 swap it on chevrolet and dodge and wandering if it was a performance mod. Some where in my head it feels like old ford firing order used on EFI is not the best way to go. Will you explain batch fire to me so i can see why it makes no difference to EFI what firing order is used. I Don't intend to be or seam redundant in my questions. Ive always been the one that says but why is it like that even ad a kid.

 

[GTO44]

Thanks for your help, can you or anyone tell me why ford changed the firing order when they started EFI . I am familiar with optional 5, 7 swap it on chevrolet and dodge and wandering if it was a performance mod. Some where in my head it feels like old ford firing order used on EFI is not the best way to go. Will you explain batch fire to me so i can see why it makes no difference to EFI what firing order is used. I Don't intend to be or seam redundant in my questions. Ive always been the one that says but why is it like that even ad a kid.

apparently the HO firing order was adopted with the 351w to lessen the load on #1 main bearing. I’ve also read it was to make the engine run smoother and/or sound better.

Also remember... EFI vs Non EFI makes no difference on firing order. The only thing that sets the firing order is the camshaft. There is no “optimal” efi firing order, just as long as the injector and ignition events match the firing order on the camshaft for a given engine.

 

[Lexc269]

Thanks GTO44
AS IN batch fire how is that figured in every 90°x2, 180°x4 of cam/ rotor rotation injectors are spraying and what injectors are grouped together per batch fire event. Im wondering if these are any ryme or reason to how injectors are batched
(grouped ) together. Thanks guys these are questions that when answered will give me a better understanding of Ford EFI Batch fire injection.

 

[GT Madness]

The 351W firing order also purportedly eliminates the possibility of crossfire between two of the cylinders.

There's some confusion of terms here. "Batch-fire" is when all the injectors fire at once. Standard MSII-based systems are not strictly batch-fire. They have two injector channels that either fire at the same time(batch) or alternating, which is called bank-to-bank injection. They can also be fired multiple times per engine cycle in either mode to improve low-rpm running, but the more squirts per cycle you command, the more important it is to have the injector dead time and voltage correction spot-on.

They can also be upgraded with expansion boards that allow semi and full sequential injection.