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I changed my air filter and was surprised there is no maf sensor. I thought maybe it was hidden somewhere in the charge air cooler area so I read through the self study and there isn't one.
I changed my air filter and was surprised there is no maf sensor. I thought maybe it was hidden somewhere in the charge air cooler area so I read through the self study and there isn't one.
Yep, they seem to go away with blown motor designs. Though I though my Mini turbo still had one in their design.
My 2.7t has one as well as my 1.8t. Cummins 6.7 also had one. It would be interesting to hear from the engineers why they did away with it on the 4.0t.
Also the K&N fans can have at it. Although I doubt they will see any gains. That air filter is pretty impressive. If someone wanted to flow more air they could simply install the S8's second air box and plumbing.
My 2.7t has one as well as my 1.8t. Cummins 6.7 also had one. It would be interesting to hear from the engineers why they did away with it on the 4.0t.
Also the K&N fans can have at it. Although I doubt they will see any gains. That air filter is pretty impressive. If someone wanted to flow more air they could simply install the S8's second air box and plumbing.
Agreed on K&N's. Certainly great MAF killers and saw it on my C5 4.2--as probably did a lot of C5 owners when over time Audi finally recalled them for it. Back in the day I used to study the paper filters, and found the pleat count varied depending on specific manufacturer by a fair amount. I would go for the ones with more. Harder to check out in this era of so much web buying. And ever since I had twin boxes (both recent D bodies) I moved beyond it anyway. Flow rate on these I expect is very good; biggest issue on D3 W12 or S8 was more keeping the bugs and debris crap cleaned off filters (like every 20K) since it was almost straight in ram air feed with only about a 12 inch total path to boxes head on. Turbos have more convoluted air paths in general, but not remotely like some of the pedestrian or miles long stuff I have seen on GMs, Chryslers, Toyota, Mini,etc. Also on a turbo, basically motor sensors look for a certain boost level anyway so it just keeps pumping till it gets there. Might affect responsiveness a tiny bit, but shouldn't affect absolute flow rates. And again, factory has thought this through far more than K&N's one size fits all marketing spin.
Makes sense that they can calculate flow using the other sensors. I also suspect it relies heavily on knock and O2 sensors. That is why higher octane fuel bumps HP so much. Not sure if you have looked at the filters in your D4 yet but they are a 2 stage design. Also it's a joy to remove and replace. The D3 air box was a nightmare.
On another note I did notice that the rubber seal around the engine compartment is cooked and brittle at the back above the turbos. I'll have to have that fixed next time i'm at the dealer.
09-26-2016, 02:01 PM
4.0t No Maf Sensor
