My Intake Quest May Have Ended.....

[ILM35XDriver]

While researching the issue of our M35 MAF location and the requirment we have that others do not in relocating it, I found this article. I am now very hesitant to to use anything other than the factory box.

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One critical design feature of this system, which differs from those used on most other vehicles, is the installation of the Mass Air Flow (MAF) sensor into the Upper Air Cleaner Case - instead of its own housing which has been traditionally the case with MAF equiped vehicles. It is primarily due to this design feature that problems may arise from modifying the factory air cleaner system.

When changing the factory air cleaner system out for an aftermarket system, you are required to relocate this MAF sensor into the new system. Due to this relocation, we have now opened up the potential for problems to occur.

The Mass Air Flow (MAF) sensor is a critical sensor used by the engine management system. The job of the MAF sensor is to monitor the Mass of air that is entering across the intake system. This is important because all of the fuel, timing and other critical engine management decisions are based primarily on what the MAF is reading. If this reading is off, then so will the fuel, timing, etc which has the potential to cause poor driving conditions or worse, engine damage.

MAF Sensor Housing SizeThe MAF sensor only samples a small portion of the air coming into the system. From that sample measurement, the engine management system can calculate how much air is actually entering the system because it knows the inner diameter of the MAF sensor housing it is sampling from.

If the MAF sensor housing inner diameter changes in any way, the calculation performed by the engine management system will be incorrect. This means that the amount of air actually entering the system will be different from what the computer thinks is entering the system. This is critical because the computer determines how much fuel and timing to run based on this value of air. When it's wrong, it can cause the engine to run richer, or leaner, than it should.

With aftermarket intakes, it's extraordinarily common for the piping used to have a different inner diameter than the MAF sensor housing incorporated in the factory air box. This is due to the fact that the exact inner diameter of the factory MAF sensor housing is different than what's commonly available in the standard metal piping used for aftermarket intake systems.

It is true that some aftermarket intakes show an increase in power when installed on a stock vehicle. This power increase is due to the fact that the aftermarket intakes have a larger inner diameter for the MAF sensor housing to mount into which in turn leans out the Air/Fuel mixture because of this error in calculating how much air is actually entering the system.

Please note this is NOT due to the fact that the aftermarket intake is so much less restrictive than the stock air box and therefore more air is getting in but rather that the computer does not know it's now sucking from a larger tube and therefore more air is getting in.

So to recap, whenever the MAF sensor housing size is increased compared to stock, more air will enter the system than the engine management has been calibrated for and you will run leaner. If the MAF sensor housing size is decreased compared to stock, less air will enter and you will run richer.

TurbulenceIn order to accurately measure the amount of air coming into the system, it is important for the air to flow smoothly across the MAF sensor. Any turbulence in this air flow will create errors in the amount of air measured versus what is actually entering the system.

In the factory air box, engineers utilize internal ribbing on the inner sections of the cases to dampen pressure waves and promote a laminar air flow into the MAF sensor housing. The MAF sensor housing itself is straight and smooth internally and positions the sensing portion of the MAF sensor properly in the air flow stream (ie: not offset to any angle left/right or up/down).

For aftermarket intake systems, turbulence across the MAF sensor is an all too common occurrence. Often times the MAF sensor is placed in close proximity to a bend, pipe joint, or weld. In the case of some hot air intakes (ie: Short Ram), the MAF sensor is mounted directly after a conical intake -- well before the air has a chance to smooth out.

When this turbulence occurs, the MAF sensor will suddenly see more or less air then it had previously. This will cause the engine management system to respond by making the engine run leaner or richer for as long as the error from turbulence occurs. The most noticeable driving characteristic associated with this would be a hesitation or flat-spot in the engine's power deliver. A worse case scenario would be the engine suddenly leaning out while under full throttle that resulted in engine damage.

Unlike the errors created by the different size of piping, there are no corrections one can make for an intake design that allows turbulence across the MAF sensor.

[fiveliterbeater]

which is why i custom made my own CAI. i just cut away the entire MAF housing section away from the airbox with a hacksaw, went to home depot, took about a foot and a half of PVC piping and some turbo hose from freightliner parts department, along with hose clamps and put together my custom CAI. (and of course cut away a section of the plastic undercarrage to allow fresh air to enter the filter)making your custom CAI isnt rocket science, you just have to be creative. my car is constanly drawing in cold air from outside the eninge bay which gets kinda hot after awhile.

[cruzad3r]

While researching the issue of our M35 MAF location and the requirment we have that others do not in relocating it, I found this article. I am now very hesitant to to use anything other than the factory box.

can you please post the link where you found this article? thanks

[ILM35XDriver]

Does not sound like a bad idea.. just hate loosing the option of ever going back to stock if I needed to. If I can find a used box some where cheap to hack of the MAF area, I might go that route. Thanks for your thougths!

[ILM35XDriver]

I did not save the site in my favorites so let me dig through my history to see if I can find it through all the sites I have been on.

[svard75]

I second your findings ILM35XDriver. These intakes are designed for race cars that have an external engine management system with active tuning capabilities. Installing this onto a stock E.M.S. would throw off everything mentioned in this article and eventually codes indicating an issue.

The filter is another problem point. Oil based filters do not filter sufficiently for our stock engines. They were originally designed for off-road use where the engines are rebuilt often.

If you REALLY want something like this and don't care about anything we say at least go with the AEM DryFlow universal air filter. It's a reusable washable air filter that doesn't need oil.

[ranman63]

I wonder if this would work?

http://www.racinglab.com/taked....html

[cruzad3r]

i'm not sure anyone here actually have a k&n filter on their M35 for a long time and actually got an error or issue with their maf but coming from the German car and having a K&N filter (oil based) on my TT for 60K+ miles, i still didn't go through or have any issue with my MAF. Also, when my brother had his 350z, he installed a cold air system from AEM, not sure if that was oil based filter but he had it on for at least 2 years and nothing happen to his MAF neither.The key with reusing K&N filter is that when you wash it, make sure you use the cleaner from the recharge kit. Wait till it completely dry, then lightly spray the oil onto your filter. Again, KEY DO NOT over spray with the oil and you'll be good. SInce this is my very first Infiniti (other than my brother I30, my dad Qx4) which i don't really care for or did any mod, i'm still learning and reading on what works and what doesn't work for the M35. I think that unless anyone here have first hand experience on things, we shouldn't spread false info.

Jake

[RONSM35X]

I have a K&N filter on my car. I put it in at about 10k miles and now I'm up to 62k and no problems. My car is only a 08 but as u can see i Love 2 drive and had no engine problems . Knock on Wood but with me talkin about it.....

[jonlex99]

i'm not sure anyone here actually have a k&n filter on their M35 for a long time and actually got an error or issue with their maf but coming from the German car and having a K&N filter (oil based) on my TT for 60K+ miles, i still didn't go through or have any issue with my MAF. Also, when my brother had his 350z, he installed a cold air system from AEM, not sure if that was oil based filter but he had it on for at least 2 years and nothing happen to his MAF neither.The key with reusing K&N filter is that when you wash it, make sure you use the cleaner from the recharge kit. Wait till it completely dry, then lightly spray the oil onto your filter. Again, KEY DO NOT over spray with the oil and you'll be good. SInce this is my very first Infiniti (other than my brother I30, my dad Qx4) which i don't really care for or did any mod, i'm still learning and reading on what works and what doesn't work for the M35. I think that unless anyone here have first hand experience on things, we shouldn't spread false info.

Jake

I had a short ram intake for a month or so. And a MAF sensor later the oe air cleaner is back on... If any one is interested in a Intake for their M let me know...

[cruzad3r]

I had a short ram intake for a month or so. And a MAF sensor later the oe air cleaner is back on... If any one is interested in a Intake for their M let me know...

so is your filter made by k&n? how long was it on the car?

[rgb129]

I have had mine on the car for ~10K without any problems. I have had them on previous cars 100k+ without any problems. The key is not to over oil them with cleaning.

[jonlex99]

I have the Fujita intake and filter. If anyone is interested let me know..

[jonlex99]

so is your filter made by k&n? how long was it on the car?

No.. I have the Fujita short ram intake.

[jgarci321]

i have a k&n on my 03 m45. its been on for over 30k. no issues...

[DeanM45]

I wonder if this would work?

http://www.racinglab.com/taked....html

I can't respond to your PM as they are not enabled for you. You can email me at dm19959 at aol dot com regarding the speaker question.

Any intake will "work" but how good (or bad) depends on your set up (tuning) and brand to some extent.