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230 Kompressor Airbox

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18K views 45 replies 10 participants last post byĀ  LeonardoDaBenz Ā 
#1 Ā· (Edited by Moderator)
Mod edit-any videos in this thread if not available have been removed by youtube, not OP.

I'm sure this may have already been covered before on here but couldn't see it with a quick search.

Quick spoiler: there's free Throttle response to be hadšŸ˜‰

So anyone with a 230k car whether Slk or any other variant maybe interested in this, I thought I would do a little video on the design of these airboxes because anyone who hasn't pulled their car apart might want to see just how flawed the stock intake is.


When I started the video I didn't have any intention of doing what I actually did and I did know these clipped apart, especially as I have had so many of these cars and engines but always assumed that it would be difficult and damage parts.... I was wrong with barely any effort at all it all pops apart, the only tough bit is the metal ring that holds the main retaining clips in place that has to be deformed to release it.

After doing this I popped the airbox back together and back on and after I realized I didn't plug the Bypass valve back in šŸ¤£, I took the car for a spin it had improved the throttle response so much. The top end is so much better to aswell as my idle speed had picked up.

Reason? Well due to the silencer in the intake for the bypass valve the actual intake is restricted to about 50mm šŸ˜®. Imagine a 50mm intake on a 2.3 Supercharged engine, all I can think is mercedes maybe deliberately did this? Either way it's easy to undo and don't worry if you don't like the Supercharger howling, it still sounds stock you can hear it but it's far from overwhelming.

Some of you may already know this trick there's got to be no way on the planet I'm the first person to do this. But I wanted to show and explain it to anyone who may not know.

So once again I hope this is useful to some of you šŸ˜ƒ

Thanks for reading and watching
Alex
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#3 Ā·
Well I can understand the Venturi effect but not the 50mm intake šŸ¤£.

One reason I can understand for them doing it is so that all the charge pressure is lost so it doesn't cause run on when off throttle.

I am coming up with a free flow quiet performance intake, I'm halfway there with the design and I actually have most of the stuff to fabricate it already. I want to keep the stock bypass valve but I think I'm going to have to baffle where the valve vents to avoid run on. But the concept will have to be made of steel to start with nothing like using a performance lightweight material like that šŸ¤£.
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#6 Ā·
Alex, now that it's been a few weeks, any problems with this mod? Did you keep it or revert to stock?

Thanks
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#7 Ā·
Hey @Solchris so far no issues at all, very faintly you can hear the Supercharger but it's only very slight. Performance is still good even with the engine being a bit poorly (unrelated issue) throttle still nice and sharp. The good thing about this mod if your careful it can easily all be refitted into the airbox, but so far I think it's absolutely fine šŸ˜ƒ
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#8 Ā·
I had an airbox lid in my hand at the wrecking yard a few days ago but I got distracted and didn't buy it. If I get back down there again I'm going to grab it and pull all the baffles out so I can do back to back runs.
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#9 Ā·
That's a good idea I noticed definitely sharper throttle I also am missing a muffler though, so my exhaust is straight through flow wise other than cats. Im not sure if it's that or the air box mod that's helped the top end so much. But I'm sure you will notice similar gains to me.
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#14 Ā·
For anyone else interested I have also made a second airbox modification, this modification I may have even already seen on here at some point but I believe my way is a slightly more effective method.


Now don't expect miracles from this mod but it really helped the top end instead of choking the now pulls all the way to the red line.
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#31 Ā·
Alex.M-oneeleven said:
For anyone else interested I have also made a second airbox modification, this modification I may have even already seen on here at some point but I believe my way is a slightly more effective method.


Now don't expect miracles from this mod but it really helped the top end instead of choking the now pulls all the way to the red line.
Click to expand...
Alex, do you have any guesses as to what would happen if I drilled out the box on my 03 facelift? There isn't much room on the wing side (or 'fenders' as we say here) but there is a fair amount of room behind the headlight. TIA.
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#16 Ā·
Interesting that Alex. It would also be interesting to see how it's performs with just the holes in the box and the main inlet pipe blocked off. I ran V12 Jags for many years and the standard mods for the early injection models were additional air pipes to the filter boxes plus of course bigger throttle bodies, low loss filters and a re chip. It certainly made a difference but I was never sure which bit if any had the greatest effect.
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#17 Ā·
That is certainly would be something easy to try see how much of the overall volume is now being drawn through the holes. The main thing I'm trying to prove with this is how much more spritely you can make the 230, without actually spending any money and so far most of it is due to the airbox. I have also ordered a Pipercross panel filter for it see how much that helps.
PIPERCROSS AIR FILTER PP1385 MERCEDES C180 C200 C220 C230 C240 C250 C280 CDI D T | eBay
Although this car is remapped, it is worth remembering that the map does not aid the throttle response and so far I would say I've increased the throttle response at least twice what it originally was. To start with you would blip the throttle it would rev up between 1-200rpm with the 1st mod that increased it to between 2-350rpm each time you blipped it, now with this mod its between 4-650rpm this is just a quick tap on the throttle pedal and it is instant. And I also now don't run out of boost up the top end the car pulls all the way to the red line now where as before it backed off after 4000rpm.
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#19 Ā·
Right guys so today I got round to sort of flow testing filters I use that term loosely, the reason for that it was a visual test rather than scientific test.


So I got myself a nice Pipercross panel filter to go with my airbox mod, but I wanted to side by side test them. Now I didn't bother trying to show a performance difference as it's a very minor improvement, I also have no suitable roads to show how much better the top end is.

However there is an improvement, but as you would guess there is also a increase in sound levels so you can hear a lot more of what's going on in the airbox. Now I know a few of you won't want to hear the Supercharger screaming, but that's not an issue if you have the airbox without the second mod .
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I recommend this filter and will leave a link below for any of you guys interested. This was the cheapest available one I could find and it arrived very quickly.

PIPERCROSS AIR FILTER PP1385 MERCEDES C180 C200 C220 C230 C240 C250 C280 CDI D T | eBay

There's only three more available from there so be quick šŸ˜‰. The part number is Pipercross PP1385.

Thanks for reading and watching guys šŸ‘šŸ˜ƒ
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#21 Ā·
First ride was promising (or wisfull thinking...)
When the compressor is kicking in the whining is louder (big plus)
Below 2500 rpm the engine looks like to run calmer. Above 2500 rpm it seems to pick up faster with less throttle.
Thinking of restriction. The air intake from filter to engine is "doubled" . The air flowing trough the filter is now restricted by the intake from the outside. Next mod......?
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#22 Ā·
JohanWT said:
First ride was promising (or wisfull thinking...)
When the compressor is kicking in the whining is louder (big plus)
Below 2500 rpm the engine looks like to run calmer. Above 2500 rpm it seems to pick up faster with less throttle.
Thinking of restriction. The air intake from filter to engine is "doubled" . The air flowing trough the filter is now restricted by the intake from the outside. Next mod......?
Click to expand...
Exactly what I expected to hear the car seems less laboured to pick up, now you could do what I did to the side of the air box but I must warn you the SC noise gets substantially louder by doing that. If you watch or have watched both of the videos you can hear how much louder the SC is you also can hear the bypass valve venting. But yes at this point you start becoming restricted buy the cold air intake, if you do the holes in the wing side of the air box exactly as I did you will feel that the car just keeps pulling after 3500rpm. Where are before the car seems to run out of power around 4000-4500rpm.

You could also try a Pipercross panel filter before going as extreme as making 32mm holes in the airbox.
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#25 Ā·
I was shocked today. On the way home this afternoon I wanted to see how far it would rev. Normally it start to stutter as it passes 5000/5500 rpm with full throttle. Now it keeps on going! I chickened out when it passed 6000 rpm, then I shifted to 4th....
I am impressed that such a small mod makes such a big difference. Wonder why Mercedes didn't come up with it themself.
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#26 Ā·
JohanWT said:
I was shocked today. On the way home this afternoon I wanted to see how far it would rev. Normally it start to stutter as it passes 5000/5500 rpm with full throttle. Now it keeps on going! I chickened out when it passed 6000 rpm, then I shifted to 4th....
I am impressed that such a small mod makes such a big difference. Wonder why Mercedes didn't come up with it themself.
Click to expand...
šŸ¤£It's surprising how much better it can breathe isn't it, it gets even better with some form of secondary cold air feed. That's why in the video you see my genuine shock I put my foot down and it pulled all the way, and due to how the supercharger works you feel it pull harder the higher the engine is revved. Which is polar opposite to how these cars start out with power dieing off as low as 4k. This is why I recommend doing these mods because it is quite literally free power or at least that's how it feels šŸ˜ƒ.
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#30 Ā·
Seems to be A1110981083. You can just read it from the photo. Interesting that it gives the performance. There's some sort of balancing act....i e replacing a "cold intake" through a smallish aperture with a warmer intake through a wider pipe and a bend. It is what it is I suppose.....
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#42 Ā·
I did a rev-out through the gears. Needs shifting at 6000 rpm before stutter begins. When shifting to 4th it was hitting 160 km/h :sneaky:

I was thinking, would it be worth the trouble of building two seperate 50 mm cold air intakes?
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#44 Ā·
Installed the modified air box today. Went for about a 15 mile run on a variety of two lane and highway. There was a bit more whine from the supercharger but if you weren't listening for it, I don't think anyone would notice. I had the top down so it would be noticeable. I can't say it was like night and day, but it seemed that there was more punch everywhere, especially at the top end. The throttle was more responsive. I don't think there is any drawback to this mod and there seems to be more power throughout, but without a dyno, I couldn't say how much. I'm going to leave it in place.
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#45 Ā·
I like the idea of extra air vents in the lower part of the air box however warm air will always be drawn in from the engine bay! my answer would be to make a baffle plate fixed to the inner flitch panel and somehow shielding that side of the inner wing and also to channel air from behind the headlamp which would be mainly cold air compared to the under bonnet (hood) temp. My car is mothballed for the winter but give me a few months and I'll be making up one.
The yellow outline in the pic shows the area to be shielded. As you can see I have already drawn air up from this area. By the way I'm liking the way this thread has thrown up good solid working ideas.
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