Help Please!

turtle64b · 03-26-2018, 10:28 AM

Quote:

Originally Posted by MoulaZ

Couple of personal observations & questions mate.

1. Are you on a hybrid MAF/SD tune or SD only? If SD only, MAFs having an issue is far less likely.

1a. If you're on an SD only tune, what MAP sensor are you using and where have you tapped into the intake manifold?

2. Whenever me and Seb tried to do a hybrid tune, it always ended with all sorts of hesitations and idling issues. Going back to SD resolved it.

3. I've never seen good equal flow with the A2A pipe, but like I said earlier, it's kinda a non-issue if you're SD only and nothing wrong with your MAP Sensor setup.

4. A suggestion I could make is what my previous Tuner did earlier on which was to bridge the MAF voltage output to each other. Single cable. Effectively makes the MAF voltage signal identical accross both. A good Tuner should still be able to make it work and if nothing else, it'd be curious to see what effect it may have for you. When I was attempting a hybrid tune, this little trick helped quite a bit.

5. I've even gone so far as to chop up my A2A pipe and add 3 honeycomb air straighteners, before the Y & just before the MAFs. Still never saw equal airflow, the airflow just stabilized, but on average I see approx 45-50% more air flowing past the 'outside' run, to the 'inside' run while under low throttle conditions. Under medium to heavy throttle they quickly even out. It definitely helped while attempting a hybrid tune, but SD still won for 'around-town' drivability. The difficulty achieving equal flow across the MAFs was a pet peeve of mine from day 1.

6. Long shot, but way early on, I was getting all sorts of sh*t AFR readings from one bank only. Long story short, it turned out the gasket between Intake Manifold & Lower Plenum had a minuscule tear leading into Cylinder 6. I did pressure test as well, but I didn't find it. Anything past the TBs I usually attributed to air leaking into Cylinders and back out the exhaust. Changed the gasket and it was a night & day difference. AFRs were 100% back on point.

1. On a hybrid tune, talking with Seb about potentially going straight speed density if the flow/MAF issue can't be resolved and significantly impacts the engine performance/safety.

1a. I have the Omni 4-bar sensor recommended by Seb for this application in the stock MAP sensor location, back driver's side of the manifold.

2/3. Looking in to straight speed density.

4. The only issue with that is the running really rich if you send the higher-flow signal to the ecu. Since flow is not balanced, you really need the average flow from both branches for it to be accurate. Could splicing the wires together cause damage since the voltages would not be equal? Once you get into electronics that small, even small voltage irregularities where they are not supposed to be can be bad.

5. I didn't really look into the logs until now since the car seemed to be running fine. The MAF disparity existed even while the car was running fine under previous tunes, which is weird. I'm thinking that maybe the increased airflow from the 9lb pulley and the Si trim impeller may have caused the greater disparity and therefore made the car perform worse?

6. How did you find the tear? I am trying to avoid tearing down if possible... Trust me, I ill not hesitate to do what must be done, I just feel like an air leak happening all of the time would show in the car idling higher or something like that.