Does my 87 300E have a Mass Airflow Sensor? If so, where is it located and what does it look like?

Regarding K&N:
Did anyone mention gas mileage?
I have been using K&N air filters for years and always notice an increase in MPG.
The larger the engines displacement, the bigger the MPG gain. 6mpg difference in my full size pickup and 3 in my 300E.

Angel

I truly find that hard to believe.

Come one people, Back Me Up Here..... I have been installing them in every car I own/owned for the last 15 years.
Always get an increase in mileage.

Logic won't allow me to accept your statement. If true, you've single-handedly discovered a way to reduce our dependence on oil for transportation by roughly 10 to 30%. Auto manufacturers go through Herculean efforts just to squeeze 1% more mileage out of a car. I don't think they'd ignore something as simple as installing a $(50?) filter to achieve a 10 to 30% gain.

No your fuel injection system is KE. The mass airflow sensor is a component of LH & HFM injection systems.

Just try one Kestas. If not in one of your vehicles then buy one for a friends. I am quite sure that they will notice a difference if they do an accurate mileage comparison.

I know that I'm not the only one who has noticed a gas mileage increase :cool:

Just putting in a clean filter of any description can restore your mileage to the proper figures. Driving around with a filthy one, then changing to K&N can distort your perception of what the K&N is really doing for you, both in power and mileage. Just my $.02.

Sorry to post this so late . .
 

but if you haven't seen this, read it with interest . . .

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

I have removed my K&N filters for good-old-paper!

Greetings Jim,

Appreciate the link to this interesting whitepaper.

I want to share a maximum airflow formula to use when determining whether the air filter is really the bottleneck in your intake system. The background for this discussion is my previous experience tuning forced-induction V6 engines. Effective displacement of those engines was comparable to any respectable V8, and the tuning requirements arguably more complex.

Unfortunately most of my "black art" tuning models were developed using output from the MAF/MAP as measured by an OBD-II compatiable scanner. My 1995 E420 more or less leaves me "blind" to engine performance tuning at this point. One of the sacrifices I made by choosing a pre-1996 model Mercedes... anyhow, back to the formula:

(eng speed * displacement) / 3456 = xxxx cfm * VE

where units are standard, and VE is engine volumetric efficiency.

Let's use the 5.0L 119.974 as a working example:

The maximum engine speed for an unmodified 119.974 is 6000 RPM. Displacement is 4973 cubic cm, or 303.5 cubic inches. Maximum horsepower is measured at 5700 RPM, the stock full-throttle (WOT) shift point. Our question is whether the filter affects ability to reach peak engine output at the highest shift point.

(5700 * 303.5) / 3456 = 500.56 CFM

This figure represents the theoretical airflow through the engine without restriction and without accounting for thermal issues. The volumetric efficiency (VE) factor allows us to account for limiting factors (material, thermal, etc.). The M119 mostly suffers from underhood thermal issues, especially with an aluminum block that soaks up ambient heat.

If we use the common 85% VE factor, estimated airflow at 5700 RPM becomes 500.56 * 0.85, or 425.47 CFM. The 119.974 engine attempts to pull a maximum of 425 CFM through the filter and intake, assuming no underlying mechanical problems that would decrease peak airflow.

It seems to me that most stock (paper) filters are tested to flow at least that much air, if not more. My interpretation is that you will never encounter a need with an unmodified 119.974 to flow more air through the air filter than a stock paper element allows.

It also goes without saying that a comparable K&N product flowing 3000 CFM allows more dirt, oils, woodland creatures, etc. to pass through the filter than the paper filter. This has been demonstrated using empirical methods like those described in the whitepaper, and through basic oil analysis from engines where a free-flowing intake filter is used (higher silica content and other particulate matter). I wonder just how many performance engine failures are due to oil breakdown once too much airborne junk passes the filter barrier.

Agreed with Jim -- make mine a quality paper filter!
-DM

Funny my car runs better and accelerates better with the standard paper filter than it does with the K&N! I am talking about my 190E not my C class. The C class I would never put a K&N in due to the MAF and me not wanting to need to buy a new MAF for it!

Anecdotal
 

I've had KE filters in my 400E for over 100K miles. No problems. Can't comment on before and after mileage but car does get 27 mpg in hot weather interstate driving at 70 mph. Car has 128K on it.

I've had a KE filter in my 944turbo track car for over 55K miles. No problems. I installed the MAF system 8 years ago. It came standard with the system.

This argument goes on and on and probably will never conclude. It's almost like an argument about religion. No one will have their mind changed....

BTW, I also use green antifreeze. My SL is 25 years old. The green stuff has not harmed it or allowed it to be harmed. But I do change antifreeze every 24 months.

I was wondering if that article would show up. I'm sure it's correct, or close. If people want to say that a paper filter doesn't flow quite as well, but "good enough," then I say a K&N filter doesn't filter quite as well, but "good enough!" :D

DangerMouse:
It's not quite that simple... Even a carb/EFI mfg will tell you need more than the calculated # at 1.5" vacuum or you're screwing yourself. (We are talking 1.5 right?) A good 50% larger is a nice start ;)
I bet the oem EFI on my little 320 is capable of flowing 4 times or more what your formula says. Shoot, even my 2.3 4cyl intake system is huge, the motor could never flow that much. I'm a fan of flow and all, but I wouldn't go that big.

benzfan:
I agree 100%, that's how Split Fire spark plugs made $$. Guaranteed to perform better! They never said guaranteed to be better than a new plug, because it can't.
One key factor for me on the K&N is that it still flows well when it's dirty. So keep your paper, just remember to change it constantly if you want those flow #'s.
I see a lot of dust in my truck and would need a new paper filter every 20 miles. Paper would start out with degraded performance from square one, but would go down hill quickly from there. My K&N always flows fine.

My 190E was kinda sluggish and I installed a K&N air filter and it actually helped. I didnt feel a difference in power, but it helped.


I feel a difference with a K&N air filter on my ATVs. But they dont filter good at all. Foam filters are the way too go.

Greetings Chevota,

I have to disagree regarding theoretical airflow calculations: it really is a simple matter of physics. That formula is a longtime staple of internal combustion engine physics taught from Stanford to Stuttgart. I think it is mentioned in every ICE design text on my bookshelf, and one of the first taught to automotive engineering students.

If you have an open mind to learning about this subject, please continue reading. The theoretical airflow calculation results in the most *optimistic* value possible under normal atmospheric conditions, based on physical dimensions of the cylinders. I would be glad to recommend engineering texts to anyone who wants to take this subject seriously.

I presented a simplified version of a more accurate equation for determining intake requirements. Here is the original formula version, using the 119.974 for reference:

bore * stroke * pi = cylinder volume
3.79in * 3.35in * 3.141... = 39.88 cubic inches

cylinder volume * # of cylinders = total displacement
39.88 cubic inches * 8 cylinders = 319.04 in^3 (cid)

cubic inches / 1728 = cubic feet (we are calculating cfm)
319.04 / 1728 = .18463 ft^3

displacement (cf) * engine speed (rpm) = airflow (cfm)
.18463 * 5700 = 1052.39 cfm

Looks like the old DangerMouse goofed, right? Wrong.
We still need to divide that value in half because any beginning student knows that a four-cycle engine breathes air every other revolution:

1052.39 / 2 = 526.19 cfm at 5700rpm

Remember the message earlier about volumetric efficiency. Everything about tuning a forced induction setup has to do with increasing volumetric efficiency of the end-to-end system.

Forced induction systems function by increasing the intake charge pressure above atmospheric ('xx psi boost'). The same thing would happen if your naturally aspirated car exceeds some absurd vehicle speed.. air molecules would compress, increasing your effective atm. Back to physics 101, heat is generated by friction whenever air molecules are compressed.

Theoretical volumetric efficiency thus exceeds 100% as engine displacement has not changed, but is brought back to reality because of heat-induced efficiency loss at the intake manifold and supercharger housing. Note that this is the basis for all thermal management via intercoolers... decrease the pressurized intake charge temperature before it reaches the cylinder.

Anyhow, the well-designed street engine (na) realizes 80-85% volumetric efficiency at maximum engine speed.

This means that the 119.974 on a good day is sucking in 526.19 * 0.85 = 447.26 cfm at 5700rpm.

447 cfm is still far below the capacity of a K&N 33-2678 panel filter; any reputable paper element (Hengst, Knecht, etc.) can handle those flow requirements without breaking a sweat. My last car with a six-inch K&N cone filter flowed 405 cfm in good conditions under maximum boost pressure; much lower than the filter rating and stock throttle body limitations with room to spare.

If someone wants to select a free-flow / low-restriction filter for reasons other than performance gains (K&N marketing spin), more power to you. I think you will run the risk of introducing particulate compounds (esp silica) that can eventually damage the cylinder walls.

I also think you run a higher risk of damaging the delicate MAF element with the K&N filter oil. I had to replace mine twice in three years because the wire element was destroyed by filter oil blowby. Just something to consider.

Regards,
-DM

Chevota,

For a dusty environment have you considered an oiled foam filter (with specialized oils) such as used on motocross bikes? They provide excellent filtration and flow and are infinately re-usable although they do have to be cleaned thoroughly and often.

Jorg