The Two/Twin/Double/Dual/Cold Air Filter/Cleaner Intake/Scoop/Snorkel/Tube/Hose...

[BabyBlueBenz]

...Modification Narrative

Two years ago, shortly after purchasing my 1986 560SL, I read everything I could find regarding performance improvements for this car. There are very few bolt-on parts available, and there aren't many How-to's that a shadetree mechanic like myself could perform with confidence and without armloads of money. Given the decent production numbers of the R/C107 chassis, you can interprete the absence of performance parts as a compliment to Mercedes Benz, who built their vehicles so well that there was nothing to improve. More likely, there just wasn't any demand for performance parts by the rich folk who originally bought these cars...beyond those wealthy enough simply to by an AMG-tuned model.

I think the situation has changed. With many worn (some still "cherry") but loved cars still on the road now in the hands of a younger generation, the desire to improve these cars is strong. The availability of replacement parts via online sources makes maintenance as easy as any other car out there. With a genuine Service Manual on hand and the prolific assistance provided by forums such as this one, intimate knowledge of these machines abound. Lots of ideas are to be found, but few DIY'ers are willing to pioneer them on their cars.

ShopForum member "Greg in Oz" is one pioneer who deserves recognition for work on his early-vintage R107: See his efforts at Improvements to M116 in early 107 (true cold air intake)

So, here's my experience in converting the stock 560SL single-intake air filter to a dual arrangement. The basis of this change the dual-snorkel air filter housing from the SL's big sisters, the 560SEL sedan and 560SEC coupe. All three vehicles have the same M117 engine, but the SL's is rated at 227 horsepower while the SEL & SEC make 238 HP. One of the few differences between the installations of this engine is the air filter configuration. With the convenience of (but potentially risky) online auction sites offering used parts, I tackled the challenge with the steps detailed below. I have no proof that this modificaton will increase your car's performance, and the details provided below are for entertainment purposes only. Altering the components of any road vehicle is potentially dangerous to the occupant's health and might be illegal where you live. Only those individuals comfortable with modifcation procedures, knowledgable enough to engage them, and qualified to deal with their potential _unsuccessful_ outcome should engage in such practices. Consider the mantra: "If it works, don't fix it".

Now, here's what I did to my perfectly good 560SL...

[BabyBlueBenz]

One good look at all of the equipment tucked in the engine compartment of the 560SL suggested to me that in order to add something into it, something had to come out to make room. Residing in a fair-weather state and considering existing problems with the climate control system in my car, I decided that a long term goal would be to remove the heating, ventilation and air conditioning (HVAC) system entirely. This decision was reached prior to, and independently of, the air filter modification. The dual-snorkel setup may very well be executed without such a drastic deletion, but I would expect it to be more difficult.

Here's a "before" photo of a typical R/C107 engine bay/compartment, with items-of-interest called out...



Photo Credit: ShopForum member "derryb' at http://www.peachparts.com/shopforum/vbpicgallery.php?do=view&g=101

[BabyBlueBenz]

At the beginning of my HVAC-purge, one of the first modifications to my car was to bypass the heat exchanger, its plumbing and associated fixtures. In relation to this task, I installed a digital temperature gauge in the center console and a new water temperature sender within the section of new/bypass hose.



No longer needed, I removed both the Monovalve and the Auxiliary Water Heater from the passenger side firewall.

Another system sacrificed for the benefit of this project was the windshield washer (labeled "WW Tank" in the first photo). I removed the tank with its built-in pump, the hood-mounted nozzles and the interconnecting washer-fluid delivery hoses. Related electrical wiring, which terminated in multi-pin plugs, were sealed with silicone caulk and, once cured, gently tucked into and under the wiring-spaghetti passing over the passenger-side fender.

P.S. The Anti-theft Alarm Horn was also deleted, and the Control Unit (located behind the glovebox) was unplugged.

[BabyBlueBenz]

The coolant expansion tank is a necessity for the stock radiator, and was relocated with an improvised adapter to mount upon the vacated Monovalve bracket on the firewall. This required extending the larger coolant line that branches from the lower radiator hose ($24.95 @***.com), as well replacing the smaller overflow hose ($12.95 @***.com plus about $20 for brass couplers from the local home improvement store). The old expansion tank's mounting bracket, which is welded to the fender, was hammered flat.

[BabyBlueBenz]

The relocated expansion tank arrangement is considering temporary, as the mounting method is not ideal. The larger, lower hose partially supports the weight of the tank at an inconvenient location...the large electrical junction block of the cable connecting the battery to the starter.

The plan is to eventually replace the stock expansion tank with an aftermarket unit, such as this one made by Moroso:



Photo Credit: http://www.moroso.com/catalog/categorydisplay.asp?catcode=29766

[BabyBlueBenz]

Here's an example of the environment under the hood of a 560SEL:



Photo Credit: http://www.dragtimes.com/Mercedes-Benz-560SEL-Timeslip-5608.html

A used dual-snorkel air filter taken from a 560SEL was acquired via eBay with a winning bid of $81.



Photo Credit: eBay Seller "Sevag"

As you can see, the two snorkels on the SEL's air filter are not identical in dimensions. The left side snorkel is equivalent to that found on the SL. The SEL's right snorkel is slightly smaller in diameter. To maximize air flow, the SL and SEL parts were "kit-bashed".

[BabyBlueBenz]

First, the SEL's small snorkel elbow was removed from the housing by drilling out the rivets that affixed it to the air filter housing.



Next, the SL's snorkel elbow was removed in the same manner. The SL's old filter housing was discarded while the best-looking housing cover was retained.

[BabyBlueBenz]

The SL's snorkel elbow was attached to the SEL's vacant (formerly smaller) side with machine screws secured by washered nuts. The gap between the housing's opening and the larger elbow on that side was filled with silicone caulk.

[BabyBlueBenz]

The SEL's air filter, with its modified dual-snorkel elbows, was installed onto the engine and all surrounding clearances were scrutinized.

A few aftermarket air intake hoses were purchased (including the mis-purchase of an oval 560SEL hose) and the best fitting sections were added to route the new/passenger side snorkel toward the front of the engine bay ($26.35 @***.com). On the driver's side, the SL's stock intake hoses were mated to the existing forward intake "mouth" piece.

[BabyBlueBenz]

On the passenger side, where the new snorkel reached the radiator cowl, it was decided that a dedicated/custom mounting point or "mouth" would not be needed since the snorkel hose fit snugly between the ABS hydraulic unit and the radiator cowl. This forward-looking photo shows how a section of snorkel hose fits into position.



Previous HVAC removal efforts (Auxilary Fan and Resistors, Evaporator and Dehydrator) revealed an opening in the cowl adequate for the new snorkel to "breath" in cooler air.



This opening may be further enlarged in the future by drilling additional holes in the cowl as demonstrated by the thread at Improvements to M116 in early 107 (true cold air intake)



Photo Credit: ShopForum member "Greg in Oz" at http://www.peachparts.com/shopforum/attachments/mercedes-benz-performance-paddock/25190d1112767654-improvements-m116-early-107-true-cold-air-intake-w107-cold-air-front.jpg

[BabyBlueBenz]

These images show the driver's side snorkel mouth from inside and outside perspectives:

[BabyBlueBenz]

...is a unique 560SL engine bay modification, which hopefully yields a minor improvement in available horsepower.

[BabyBlueBenz]

Some measurements and calculations revealed an interesting relationship between the cross-sectional area of each snorkel on the stock SEL air filter and the M117's Air Flow Meter:
large/passenger snorkel's intake diameter: 72mm
large/passenger snorkel's intake cross-sectional area (pi*r^2): 4072mm^2
small/driver snorkel's intake diameter: 53mm
small/driver snorkel's intake cross-sectional area (pi*r^2): 2206mm^2
sum of both snorkels' intake area: 6278mm^2
air flow meter's diameter: 130mm
air flow meter's cross-sectional area: 13,273 mm^2
So, the sum of the two 560SEL snorkel's cross-sectional area is less than half of the cross-section of the air meter?!

Perhaps someone will be willing to install a Velocity Stack to take advantage of the full area of the Air Flow Meter. Explained at http://en.wikipedia.org/wiki/Velocity_stack

Is anyone willing to punch a hole in their hood for one of these?


...as seen at http://www.rjays.com/Engine%20Parts/air-cleaners-01.htm

[jplinville]

Nice write-up. I'd love to see a MOD sticky this thread

[Deltacom]

Originally Posted by jplinville

Nice write-up. I'd love to see a MOD sticky this thread

Ditto that!!


Excellent mod narrative BBB, and great pics. You’ve just shown it can be done and how. Great work. I just wonder whether the gains would justify the undertakings.

Originally Posted by BabyBlueBenz

Is anyone willing to punch a hole in their hood for one of these?

Some have taken it a step further, though……
As per pics posted by other forum members below......