I got an SAFC II installed in my G,,
and I found out that my MAF voltage reading can be very usefull for measuring air flow and testing different intake mods...
Tests were done during 1/4mi runs at full throttle. I did found out that Max air flow can be tested leaving car in 1st gear, tests in 1st gear were also performed and confirmed , no fluctuation was noted on readings.

Test 1: ebay Ztube (smaller diameter compared to stock but smooth) with stock air box, : Max air flow is at 72.4%

Test 2: Same setup as above but I taped main intake area, air snorkle/ram was left open : Max air flow is at 71.8%

Test 3: I swapped ebay ztube for stock intake tube with resonator removed and sealed off, stock air box : Max air flow is at 73%

UPDATE:
Test 4: cut out a hole on the bottom of the intake box where a aluminum dryer hose is routed to the front of the bumper. Max air flow is now close to 75%



safc AIR flow reading seems very useful for testing intake mods. Planning to test in future : 5/16 spacer and after market intakes.

If anyone wants to donate some intakes for testing I will be happy to do it for them.

 

Do you have your 1/4 times? Although not 100% definitive, it would be interesting to have those on the end of the airflow readings.

 

I did those with Gtech, from the worst air flow with main duct taped to the best with stock tube there was a .25 change, from around 15sec to 15.25
but I'm not sure that there would be an imidiate change because ECU takes time to adjust to new air flow numbers.

 

ECU time to adjust is instantaneous for MAF voltages. Don't confuse the fuel trim with air flow.
The short term learn is adjusted within 1 second and long term trim is > 1<2 minute.

Otherwise the engine would misbehave coming down a mountain where each 333 feet is 1% or each 11F air temp change is 1%. Sudden rain storm can change air density 2-3-4%.

Ecu must tolerate Denver vs LA where the air density is ~~ 18% different all measured and corrected from MAF voltage.............actually ecu allows a 25% from sealevel [preprogrammed] density before it throw a code.

All in all ecu resets for mild aftermarket air mods are mostly urban legend

 

Did you figure things out with yours? I still haven't figured mine out...

-Sean

 

Well after researching a while I was able to find ECU pin out, it is not the same on my G as 350z ECU it turns out.
SAFC is hooked up and all functions work like they should, at first after a hook up I had wrong settings and my car threw like 10 engine codes, so I cleared those out reset the setting and its perfect now.
Have not tunned it yet , researching my options right now, I might just get a wideband and tune it myself instead of having to go to a dyno for every little mod.

Do you have SAFC or SAFCII?

 

S-AFCII

I need to go have a dyno tune...haven't had one in over 3 years.

-Sean

 

UPDATE: I was able to get up to 73.3 % yesterday without any changes to intake
you guys have an idea if intake temperature would effect how much air is going in or should volume stay the same?

 

just get a wideband installed and you will be able to tune it yourself and see if your car is running lean or rich

 

UPDATE:
Test 4: cut out a hole on the bottom of the intake box where a aluminum dryer hose is routed to the front of the bumper. Max air flow is now close to 75%

 

Each 11F change is a 1% change in density.

Engine are usually rated at 60-70F air going into MAF.
So 120F MAF air is a ~~~ 4.5% potential decline in torque/hp.

 

i posted SAE compensations a while back, can be more significant than 4-5%.
it works the other way round too, cold temps make a heck of a lot more power. (on a really cold day,-31 C, a 260HP G could be making as much as 300HP, in theory)

 

Im aware of the corrections, especially at see level and in cold temps engine could be making some serious numbers.

Now would the temperature have an effect on the actual volume of flow which I am measuring off the MAF. I personally think that volume should stay the same when density changes which would make MAF voltage measurement a very accurate way to test mods for air flow. If someone know any different please shed some light on this subject.

 

volume should be the same. density is going to be different. oxygen content in a given volume changes with temp.

 

ok thats great!

this means I can test any air intake mod and be able to see an instant result.
Anyone got anything specific for testing in mind?