All well and good but it applies to 2004 and earlier MAF configurations. Also, "The change in calibration is a direct result of the fact that the air velocity through the MAF housing is reduced when a cone filter is mounted directly on the end of the unit, and the end result is a lower voltage output for a given volume of airflow measured." They also use this effect when talking about larger units. However, the sensor is not measuring velocity, it's measuring mass flow. Something is hinky.

 

Yes. I know. But that shows that the change in pipe diameter changes velocity and volume of air coming through the pipe. There's nothing else to factor. If velocity or volume didn't matter, you wouldn't have to tune it. Think about it... A smaller diameter will pack more air into the pipe. It will move faster which will yield a higher concentration on the hot wire. If you blow more air on something hot, it will cool faster. It does not read velocity. But it does play a factor here because it will throw off the change in temperature.

 

Mass flow is normally driven by throttle position, volumetric efficiency and rpm variables. It shouldn't change appreciably by enlarging the MAF throat. Smaller diameter WILL increase velocity but moves a smaller volume so that air mass is the same as with larger, slower-flowing MAF. The MAF hotwire voltage/current change is directly correlated with MASS flow, not velocity.

 

Lolol Okay... Explain MASS FLOW now.

Edit: you're right. Velocity has nothing to do with Mass air flow, volume, or intake temps. I'm done. I'm gonna go drink now. Happy late cinco de mayo fellas lol

 

The MAF does not measure 100% of the airflow. Is samples a portion (maybe 5%) of the air flow and uses a "look up table" to determine airflow based on the stock diameter of the tube where the MAF is located.

With the AAM intake, the MAF diameter is larger, but it is sampling the same amount as stock, so the overall MAF measurement is low. (More air is entering the engine resulting in a leaner air:fuel ratio)

 

I want you two to read this. Look that that graph... I apologize for starting an argument in the chat thread... Again lol

People don't go bigger in MAF diameter and it just magically lowers the voltage somehow. Slowing down the air pulls the hot wire temp closer to its set constant which negatively affects the change in temp. This leads to a lower output signal which in return lowers the duty cycle of your injectors. Now you're lean beyond no return (Considering the factory correction limits). It is voltage signal (change in temp) VS Intake air mass (g/sec). That's the issue with boost. You pack all that air through the charge piping and it cools the hot wire beyond its ability (past 5v). Same reason GTR's do larger MAF piping after full bolt on to fix being near peak voltage signal. They enlarge MAF diameter so The air doesn't move as quickly through that part bringing the voltage signal back down (the hot wire is closer to its constant temp now). I don't understand what the confusion is anymore. A lower rate of air through the piping does effect the MAF reading. A lower velocity does not mean less air though. Thats why people compensate for MAF diameter increase with larger injectors. A weaker signal (caused by increase in diameter) leads to a lower duty cycle, then people up the size of injectors to balance it out. A lower duty cycle but a bigger injector... More air. More fuel. Same MAF but lower signal (Hotwire temp is closer to its constant temp). I think we're stressing different points? Anyways. Note to members: make sure you tune for change in MAF diameter lol

 

Hello Gents, it's been a while since I've posted in the chat thread. I'm way behind by like 100 pages on what everyone's been up to. Been very busy so that's the reason for my absence.

However I drove a Q50 Red Sport tonight posted a review here in case you guys are interested:

https://www.myg37.com/forums/g37-sed...est-drive.html

 

Damn, awesome review man. I know I'll want one later but I think I'll be too deep into my car by then haha. How did it feel interior wise compared to your g37? Smaller or cramped? I've yet to even sit in a q50. I might be in for a test drive too

 

Thanks man! I am starting to see them showing up on dealer lots but no forum write ups yet. I was shocked that I was the first one to drive their car. Interior wise, I feel like the size is perfect. The G37 is definitely smaller and I'm tall at 6'3" and have broad shoulders so the Q50 is like the Goldilocks of the lineup. A few years back, I had an M37/Q70 for a day and honestly it felt too big for my liking. I like it to feel sporty without feeling cramped, but also not swimming in the thing so to speak.

I'll go back and catch up on the chat thread posts. I was quite active here a while back and I miss the chatting back and forth.

I currently have a smoking deal worked on a new '15 Q50S that I'm very close to pulling the trigger on. The RS 400 test drive really blurred my vision with regard to making that decision. I'm still torn and the decision is going to be difficult to say the least. However, I want to see what happens with the aftermarket for the VR30...and that's going to be a while before we see anything.

 

I'm sure it will be a while! But someone with deep pockets will take the fall pretty quickly lol. I'm hoping we get another surprise at Zdayz this year. Last time I went was in 2014 when they unveiled the 2015 370z Nismo. Can't wait to drive the dragons tail again

As for the q50s I would think it's well worth it. I've only had my G for a year. I don't plan on getting rid of it... Ever lol but going and driving the Q50s will result in another impulsive buy. So I keep my distance. Im now on the hunt for something that holds boost. It will be gutted to the bone as well. I'm pretty much done with the v36 other than some wheels and coils. Maybe some baby boost if my plans work out.

 

This. I couldn't find this datum on the page Gregor linked but really wanted to address it.

 

This is a strange perspective.

 

Right... Because the MAF location is the restriction for sure, it has nothing to do with negatively affecting the hot wire temp triggering, lower voltage signal output causing the ecu to pull fuel from the table. It's just the fact that the diameter is bigger causing huge amounts of extra air to entire and the MAF is only sampling the same amount of air as stock and air is just sneaking through! Because changing MAF diameter does nothing to the amount of air being "sampled". It just moves more air through but it samples the same. So it changes but it doesn't Change therefore the change is unseen. Now air gods have snuck into your engine avoiding the sampled portion of air....

If the diameter was so damn restrictive and you were actually getting that much "more air" in your motor then you would push your injectors way beyond 85%. My cars a/f was at 16s because the MAF was sending a lower signal. When in fact there wasn't less air coming throug.. After rescaling and adding fuel I'm still only near 86% duty cycle at redline. There wasn't much air to compensate for over the stock Intakes.... Goes to show that I'm not even really bringing that much more air in over the stock intakes. I just went through all this when tuning my car with the bigger diameters. Hence the let down in power gains from the "larger diameter intakes" I did nothing but slow the air down near the MAF which dropped voltage signal leaning out my car beyond return... It's not all because the engine is finally free from its highly restrictive stock intakes... Even is they were, the throttle bodies would be next assume that the weak point isn't the intake manifold. Which also explains why the power band looked almost identical until bout 6000 rpms... Which is the only place we had to add fuel to compensate for more air coming in... More air was coming in up top... Not across the board. Which is just where the stock intakes and my purolator classics became restrictive apparently.

Flow rate is equal to the area times the velocity of the flow. Air is compressible. Just because you enlarge the MAF diameter doesn't automatically mean you're bringing in more air. This is where the flow is altered by change in diameter at the same engine speed throwing off the hot wire temp. All these play a factor with the MAF. Just because it doesn't measure certain parameters doesn't mean you can just do away with them. They're not independent of each other. Lots of good info that was dug up though. Not only does it make sense but it's been proven. I'm officially done though. Wasn't trying to argue just really wanted to get to the bottom of things.

 

Indeed it is John! Is this your car? I'm way behind on what everyone is up to mod wise but I don't remember you having that shifter on your car, unless you've changed since I last read.

 

Yep. My car, in prep this afternoon for Monday's install... TWM Short-Throw Shifter, and Z1 Motorsports poly transmission mount. That **** in the pic, it's my OEM **** with the leather rippied off from the time I removd it.

I just thought that picture was an interesting perspective on the car. Very raw and ripped open without the center console.

Getting the console out was actually pretty easy. I was expecting more PITA factor, but it all came right apart very easy.