You sure about that ? Unless you have the ECU MAF Kfactor tweaked earlier for a MAF on only one intake side. Then it should be set for ADD. So it takes into account the total air volume of both MAFS
From a theoretical standpoint, wouldn't a MAX function be more beneficial. That way the side that is pulling the most air is the determinator for target AFR and the other runs a little rich. AVG causes one side to run leaner than desired and one richer, and ADD would do the same. Do any of them come with that function? And does what I'm saying make sense? /tired thoughts
Just tune it with a wideband up both exhausts, what sort of difference in AFR would you expect anyway? I wouldn't think a difference of more than 0.1AFR.
A Max of one side or the added combination of both? The MAX function of one maf would be silly. The MAX function of both Maf`s (Added together?) would be the same? What are you getting at? For the AVG function would be a bit silly for idle. If the car is taking in 100 units of air at idle.. all from the left hand side, you have one MAF giving 100 units and one MAF giving zero units. The car requires 100 units worth of fuel to match, the ADD would supply correctly.. but the AVG would half the fuel to a LEAN idle.
Max and doubled output in ECU obviously. Arbitrary numbers. 450 / 550 Ecu supplies fuel equivalent to 550 at both. Right side runs at target AFR, left side runs rich by ~22% Average 450 / 550 Ecu supplies 500 to both. Right side runs ~9% lean. Left side runs ~10% rich That's fine when the car is running "normally". What happens when there is a large differential between the two sides due to some issue. Blocked intake piping or something that can't be balanced by balance tube?
And how often would that happen? It's a one in a million chance that should be discounted by anyone who works on their car in a reasonable manner and doesn't leave rags in the intake pipes... You won't get a large differential between the banks unless something is seriously wrong.
An identical situation occurs to the stock nissan setup.... nobody has had a problem with that? I challenge the 20% airflow difference between sides.. that is assuming a broken turbo or stuck valves.
Hey Graham , This is what i did , With the nistune i was able to correct some timing /mixture peaks/ troughs , (you end up in different parts of the maps if not 100% load ) But most of the time i wouldn't know there is a second maf fitted . And the safc does read different left and right values at idle/low throttle openings as per normal. [/url][/IMG] [/url][/IMG] [/url][/IMG]
This is the bit that wont work if you average. I will just use some arbitary numbers to get my point across. If on a 1 MAF car at full throttle the output of the MAF is say 100. If you use 2 MAF's each MAF at full throttle will read 50. If you average them its 50+50 divided by 2 which is 50 or half the reading it should have. Therefore the car runs lean. You really need it to ADD so that 50+50 =100units Even of they are unbalanced by 10% it is still way closer to correct to ADD them. Now if you tweak the MAF K factor of the ECU like if you are using a one MAF setup. Then you can AVERAGE the signals and the mixture will be sort of correct But will not neccesarily be accurate as it doesnt reflect the actual air flow.
Continuing on from tektrader. As long as you are using 2 AFMs you will still get total air into the engine. Using the AVG function you would double the MAF value in the ECU, so you'd get 50 + 50 /2. The ECU would only see 50, but the K factor would compensate for that. Using the ADD function, you would get 50+50 = 100. I would prefer that ADD function because you are getting better metering resolution. Problem though, regardless which function you use, the air supply to each bank is completely independant but the fueling is only controlled from 1 source. So if you have an inbalance in air flow there is no way to compensate, unless you have an awesome ECU capable of running two banks independently.
Thats not correct with your AVG function explanation. The ECU would see 100 in both cases. The change comes with ADD and AVG when there is a change from equal air pulls each side. And the stock nissan system also does not compensate for an air imbalance, so this is not a deviation from stock.
Nah I don't agree with that... the flow speed past the TB's is considerably less than on your intake piping because it's the same amount of air moving through each, but at the TB's it might be at double atmospheric pressure (well that's when you care ie full throttle etc) At double the pressure, the air moves at half the speed Pressure drop is a function of air speed So improvements in intake piping are most important between the air filters and turbo inlet, cos the air is moving fastest in that section
True, mathematically, you should only be looking for restrictions pre-turbo. ie if the total area of the inlet piping to the turbo is bigger than the AFM, then a single AFM will become a bottle neck as demands on air are increased with bigger turbo's. Don't ask when, cause I don't know, although I saw slightly better spool and top end breathing on HKS 2530's with the split mod.
