Modification for D-Jet M116 and M117

[Tomguy]

I forgot to mention that I took the rubber hood seal off a bit, and left it off so I could run the hoses without crimping them.

[j9fd3s]

wow those are interesting results. if you wanted to drill into the cowl thats what nascar uses, and its popular with the miata crowd too.

next test is to find a spot where there is positive pressure under the hood

[Tomguy]

There's positive pressure under the hood at the MAP sensor. You don't want to use that air though really because the air under the hood has been warmed by the radiator, thus one of the reasons you put in a cold air intake. Basically, any spot except where the air horn is would probably be better!

[yogiysh]

Tomguy, thank you, very nice test results & I like your methods too!

Greg,

I've given up on trying to devise of a away to get an air intake to area infront of the radiator as the computer and other items would need to be relocated. But where !!?? I'm not so sure about drilling holes through the firewall to get to the air intake cowl either.

I also believe that - "at speed, air passes over the front of the car at the hood seam, instead of into it. This passing over creates a lower pressure area inside the hood, at least at the air intake horn, much like the effect on the top side of an airplane wing."

On my efforts, I was just trying to get the other end of the flexihose into an area where there could be more lanimar airflow for that positive pressure in the airfilter housing hopefully so that the engine will get the sufficient air it needs rather than any forced induction. I've left the little hole on the airfilter horn open inorder to minimise this. This way I hopefully don't have to worry about altering fuel mixtures etc. or exceeding any original parameters set into the workings of the engine.

I took Tobias for a run on the freeway up the north coast this longweekend just past, to check the fuel consumption. I was worried that since the airsensor is getting cold air then the fuel mixture will be rich and hence guzzle but got a result of 216 miles on 50 litres which I'm really happy with. I kept to the speed limit of 110 kph(well, actually 70mph ~ 112kph) and only once opened up the throttle a little past 100mph. Lots of power and kept on accellerating !!

I did put a screen mesh over the flexihose opening to stop large objects that might find it's way up into the airfilter housing. I don't know if it will make too much of a difference in airflow.

I still haven't cut the tapering end off the airfilter housing but at this stage I don't like to have to relocate the air sensor in the process so I'll cut the horn just before the sensor and test for any difference - the cross sectional area there should already be greater than at the end.

Looking forward to any future test results!

Cheers,

ysmael

[Greg in Oz]

Tomguy,
Nice work with the water manometer. Great to see someone go and actually measure something to confirm any suspicions. Nice work!

Ysmael,
Good to see pics of the setup on your 108. I had forgotten that the ECU lives up the front there on the 108. On my 107 it is inside the car under the dash. It looks like you purchased the same 80mm flex hose as me only I think I got ripped-off! When I heard the price (almost $30) I nearly didn't buy it, and I only needed less than half the length in the package. At least the rest of my mod cost me little more than my time (and some black paint that my air filter desperately needed). I'm still pleased with the results of this mod on my 350SLC. Just wish I could find somewhere to really "try it out". You're brave even getting to the speeds you mentioned, especially on a "double-demerit points" long weekend. The authorities here are just so obsessed with "speeding". The days of seeing 210 or 220 (kays, not miles!) on the SLC seem so long ago now. Wonder what she'd do today?

Greg

[Damian]

Been reading your post and am very interested in doing this sort of thing to my 82 500 sl with K jetronic injection. Can you think of any problems that this may cause? Nice pics by the way Greg may do something very similar.

Regards

Damian

[psfred]

The only comment I have is that modifying the intake horn may cause flow problems, as will adding a hose to the horn.

That "restriction" is a venturi, I suspect purposely put there to increase the velocity of the intake air (and hence ram more through the filter) at large throttle openings. Removing it will cause a decrease in velocity and loss of mass flow at large throttle openings. This won't affect the mixture much, but it will DECREASE performance (so will bends of moderate or tighter radius in the tubing).

Someone posted some very interesting dynamometer curves from his 4.5L W108 with and without the air cleaner installed. Lost noticable (5% or more) hp and torque with the housing OFF .....

Peter

[Greg in Oz]

Originally Posted by Damian

Been reading your post and am very interested in doing this sort of thing to my 82 500 sl with K jetronic injection. Can you think of any problems that this may cause? Nice pics by the way Greg may do something very similar.

Regards

Damian

Damian,

This mod could be applied to your K-Jet version except from memory the 107 with K-Jet has the intake pipe on the other side of the engine bay. I remember seeing the charcoal canister located in the area where you would want to run the cold air intake so you may have to deal with this. Otherwise there should be no problem and you may even be able to use a mirror imaged version of the panel I fabricated for my 107.

Later models with K-Jet (eg. W124 & W201) had a cold air duct fitted standard from the factory. I also know of a 350SL that has a 5 litre alloy M117 engine from a W126 500SE retrofitted. This one has the air filter with two intake pipes and this owner has managed to run both from cold air intakes either side of his radiator. He would benefit from having cold air intakes and minimal restriction from the additional cross-sectional area of twin intakes.

Small diameter ducts may be used for tuned intake runners to inlet ports and for carburettor venturis where high velocity may be desirable, however upstream of an air filter element small diameters have no purpose other than induction noise supression. Increased cross-sectional area upstream of the air filter element should give some improvement in performance.

Many have tried this modification with good results. You may like to look at discussion also in some of the other forums (in the thread on this subject on the Aussie MB Club forum at http://www.mbcnsw.org.au/forum/viewtopic.php?t=16 and in threads in "Performance Paddock" and "SL Forum" here at MercedesShop).

Greg

[Damian]

Thanks Greg,
I will have a look at the threads on the aussie site.

You are right I would have to use a mirror image of the plate you made as my intake is on the other side. I have no canister though as my car is a euro version with the M117.962 which runs and open loop injection ( no Lambda control ego etc)
with not much in the way of pollution control.
To extend the intake pipe should be ok as there is nothing infront of it. I was just a bit worried if may cause it to run to lean?

What do you think?

Regards

Damian

[fever]

I wonder if this application would work for the W111 3.5? Seems that it would. Any thoughts?

[Greg in Oz]

Originally Posted by Damian

Thanks Greg,
I will have a look at the threads on the aussie site.

You are right I would have to use a mirror image of the plate you made as my intake is on the other side. I have no canister though as my car is a euro version with the M117.962 which runs and open loop injection ( no Lambda control ego etc)
with not much in the way of pollution control.
To extend the intake pipe should be ok as there is nothing infront of it. I was just a bit worried if may cause it to run to lean?

What do you think?

Regards

Damian

Damian,

You should have no problems with lean running as even open-loop systems still monitor air density or temperature in addition to flow or inlet manifold pressure (vacuum). Some K-Jet versions of your engine used one or even two ducts from behind the grille.

Greg

Originally Posted by fever

I wonder if this application would work for the W111 3.5? Seems that it would. Any thoughts?

Fever,

Several have had success with their 3.5 W108 so you should expect the same with your 3.5 W111. Engine-wise they are the same.

Greg

[Damian]

Thanks Greg,

I will have to give it a try then.

Being vice president of the NSW Club you wouldn't have seen a set of the older 16 hole deep dish Lorinser wheels to suit my car for sale up there somewhere? Would insert a pic of them but it's seems a bit hard my pic is a bit large and I cant seem to shrink it at the moment I will have to load Paint shop or some other software.

Regards

Damian

[Greg in Oz]

Originally Posted by Damian

Thanks Greg,

I will have to give it a try then.

Being vice president of the NSW Club you wouldn't have seen a set of the older 16 hole deep dish Lorinser wheels to suit my car for sale up there somewhere? Would insert a pic of them but it's seems a bit hard my pic is a bit large and I cant seem to shrink it at the moment I will have to load Paint shop or some other software.

Regards

Damian

Damian,

I think I know the style of wheel you refer to, but I haven't seen any for sale. You could try posting a "wanted" on the Aussie club forum.

Greg