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2007 SLK55 AMG
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116 Posts
Discussion Starter · #21 ·
Ok, that is a marvelous article! Very interesting, truly.


But.. NUMBERS!! :D :D

We’re going to have to get rollig road numbers :). How much does it actually do? It’s a lot of work (and money!) if it only give ”a few” extra ponnies.

Which seems to be the case. Your #1 looks remarkably identical to over-the-counter intakes that’s out there, and numbers on those indikate less than 5hp (2-3 is the last number I’ve seen) improvement..
You are correct! Unfortunately I won't have numbers until I do a back to back OBD data calculation from the 3 intakes.
 

· *Premium Member
2008 SLK55 AMG
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812 Posts
Not sure your goal of improving intake design will have any noticeable beneficial effects on your SLK55. Immediate beneficial effects may be improved throttle response, more power or torque, or fuel consumption. But what have you been measuring, right from the start, so that you have a comparison once you have completed your modifications. Mercedes have a big research and development department. But still have to work within the compromises of the vehicle. You have put these different air filters on, but even if the flow rates are better, what is the end benefit to the user? Then, as someone else has pointed out, you have the ingress of water through the bonnet louvre problem. And the T section intake tube where it goes into the MAF sensor, not giving a straight entry for good flow characteristics. I drove my (standard) SLK55 to France last year, where the daytime temperatures were 38 degrees centigrade, and the engine ran faultlessly, for the whole 2 weeks we were out there. If I was looking to improve the power of the engine, with minimal cost, my money would be with the tuned exhaust headers. They (in my opinion) give the best bang for your buck. But even then, THE ONLY WAY TO CONFIRM THIS IS TO DO A DYNO RUN, BEFORE AND AFTER FITMENT. The problem even with fitting these, is, there isn't much room down the side of the engine, to actually bolt them in. Good luck with your experimenting.(y)
 
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· *Registered
2010 SLK55 AMG
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2,521 Posts
Agree.

It HAVE been proven, over and over, that there’s little to no change in modifying the intake.

It HAVE also been proven several times that this engines problem is breathing OUT. Not in..

Without before and after numbers from a rolling road, I find this very interesting read (from a sientific standpoint), but nothing other than that.


As for the intake air temp, the air flows so quickly through those ducts that there is little time for the air to heat up.

But also, the way thermodynamics work, which I grant is a bit of a dark art still, given a heat source and you remove SOME of the radiation and convection, the heat source will actually produce MORE heat - ”heat insulates heat” somehow. I didn’t quite understand that bit in school, so can’t explain it better than that.

But my point earlier is still valid - you remove SOME of the heat with those vents, but the exhaust still produce copious amounts of it, so the net is probably as bad, if not worse!, than before. And as you say, opening up the original vents might just have made things worse..

Insulating the exhaust, even a bog standard one, will give more (in terms of lowering the intake air temp) than trying to insulate the intake.
 

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2010 SLK55 AMG
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2,521 Posts
Please don’t take it the wrong way, I applaud you tenacity and scientific rigor! You obviously understand this better than me, I only have a basic/rough understanding of thermodynamics.

But I do see my own fallicies in this (I also studied a bit of psycology - not much, but enough to see and understand why I do certain things :) ), once I get an idea stuck in my head, I have problem ”breaking out” of it. Which is why I (and others here) think that you’re approaching this from the wrong end..
 

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Post #20 shiny T is pretty much what I would've choose, if I was to improve.

On the matter about heat, the fiber...cloth and aluminium, you have the aluminium warmed once and it will still "keep" the fiber underneath heated.

We all know the cooler the air intake, the better. And as mine is SC an intercooler is a must. On that note you seem to have no space for re-routing the air intake, but keeping it cooler as long as you can.
Have you seen this:
Nickel Cylinder Rectangle Composite material Circle
K-flex, Arma-flex ...who knows what brand you can find in HVAC store near by. The aluminium is reflective for the radiation but the "rubber" is low conductive (can not say if less than the fiber you mentioned) and the "closed cell" structure is a very good insulation (general thing, right).
But it is about 1cm thick, that means space!?! You know better, how much you have, but fiber...cloth plus "rubber" and aluminium reflector... would've been better. Imagine 2 layers of insulation before the house of yours is exposed to heat cold weather outside...plus 1 reflective coating on the outside for the radiation...

And about the Airflow that Turbo mentioned along with thermodynamics we have dynamics of fluids and friction.
The different flow (change of direction) has specific resistance, that means friction, the friction is a heat source (put your both hands together press and slide, is this how you warming up your hands when cold) imagine high speed air flow that has layers, more friction? Why layers?
Well, water was mentioned as fluid and river bed has "slow" motion/speed near the shore and higher flow/current speed/motion in the middle, imagine 2 river beds on top of eachother (mirrored) - there is your air intake, lower air flow on the ends (pipe wall itself) then friction and higher flow in the middle! And one brutal (general term - contrasting speech) out of shape T piece to "force" both air flows clashing first and then going the right way.

Pardon my inaccurate explanation (far from engineering language) just I started 4 am UK time to BHX Airport, to get delayed flight, time on the airport, lack of info... finally started with nice delay, landed at the destination and currently have 2 more hours (out of 6-7 hours - total of 500km bus ride) with nothing but a coffee in the morning...the headache is...the bus stop was to a place that was having only WC working and outside coffee machine...
 

· *Registered
2007 SLK55 AMG
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116 Posts
Discussion Starter · #26 ·
Not sure your goal of improving intake design will have any noticeable beneficial effects on your SLK55. Immediate beneficial effects may be improved throttle response, more power or torque, or fuel consumption. But what have you been measuring, right from the start, so that you have a comparison once you have completed your modifications. Mercedes have a big research and development department. But still have to work within the compromises of the vehicle. You have put these different air filters on, but even if the flow rates are better, what is the end benefit to the user? Then, as someone else has pointed out, you have the ingress of water through the bonnet louvre problem. And the T section intake tube where it goes into the MAF sensor, not giving a straight entry for good flow characteristics. I drove my (standard) SLK55 to France last year, where the daytime temperatures were 38 degrees centigrade, and the engine ran faultlessly, for the whole 2 weeks we were out there. If I was looking to improve the power of the engine, with minimal cost, my money would be with the tuned exhaust headers. They (in my opinion) give the best bang for your buck. But even then, THE ONLY WAY TO CONFIRM THIS IS TO DO A DYNO RUN, BEFORE AND AFTER FITMENT. The problem even with fitting these, is, there isn't much room down the side of the engine, to actually bolt them in. Good luck with your experimenting.(y)
Thank you very much for your feedback. The interesting thing is 90% of the time we are using our vehicles for cruising, not so much full throttle. So my experimentation was to see visually what the temperature reading differences were when cruising right around 2000 RPM and around 65 mph, all else being equal across the three intake designs.

Obviously I did not take hard measurements but I did take notes during the times when I tested them out, and the temperature readings I have written in my original post we're using the intake air temperature red from my OBD port using the OBD link OBD reader, as well as comparing this to the outside air temperature on our dashboard.

What makes me curious is if there will be testing differences between my readings at cruising speed, versus doing full throttle at the dyno. Any sort of temperature reduction is going to help, however I do agree it is mostly going to help when going at full throttle. Then again according to other people's experiences this is only between 1 to 5 horsepower, whereas replacing the crappy exhaust manifolds is going to yield the best benefits (and I have currently MBH headers ready to be put on I just have to make a day or a few days for this task).

In terms of the tee pipe Yes it is not the most optimal design because you have literally 180° of both banks smashing against each other before they go 90° down into the maf sensor tubing. This is not ideal in any sense, however it is not much different from the stock intake as the stock intake also has 180° opposition from both banks, then exactly 90° down into the maf sensor tubing. If I can somehow create a smooth 90° bend from both pipes while doing all of this in a 3-in height area (The space from the mouth of the maf sensor to the bottom of the hood) then that would be perfect.

Again thanks for your feedback!
 

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For the 90°, would it be possible to ”lay it down” somehow?

As in, a 90° bend from the center line into the MAF, and just before that, the Y instead of the T?

It would mean that the tubes need to go ”on the inside” of the head, over the intake manifold, as opposed ”on the outside”.. ?
 

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2006 SLK55 AMG
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3,048 Posts
Take a look at the E55k y-pipe. It's a much cleaner junction compared to a hard T-pipe. (see attached picture)

Also, there's been a couple threads on this. It's not plug and play, but it's very light modification, and there's 2 ways you can make it fit.

Hood Vehicle Car Automotive design Motor vehicle
 

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Discussion Starter · #29 ·
I wonder why Mercedes designed the engine in a way where the intake manifold opening is in the rear rather than from the front. For instance my Corvette's intake manifold opening was in the front, making intake modifications much easier.

Then again as others have said, the intake isn't the main focus of the inefficiency, but rather the exhaust system.
 

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Discussion Starter · #30 ·
For the 90°, would it be possible to ”lay it down” somehow?

As in, a 90° bend from the center line into the MAF, and just before that, the Y instead of the T?

It would mean that the tubes need to go ”on the inside” of the head, over the intake manifold, as opposed ”on the outside”.. ?
I have thought about that as well and actually rested the Tee pipe on the intake manifold to figure out if we have enough clearance from under the hood. I think the maximum clearance is around 2 or 2 1/2 inches... So having a round y pipe or t-pipe is not going to work.

If I had a welder I could have experimented with round to oval transition pipe and making a y pipe out of that, because I haven't seen anything like that yet.

I will say though, the most optimal design would have been a tunnel ram or hood scoop intake with simply a large filter in the maf sensor housing. This way the air doesn't get affected by any of the engine and headers heat, although many would be reluctant to cut their hoods and install an actual hood scoop.

Automotive design Synthetic rubber Automotive exterior Composite material Auto part
 

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I wonder why Mercedes designed the engine in a way where the intake manifold opening is in the rear rather than from the front.
It's so the cars have space for the air filters on the sides of the engine and a straight path for the air to flow. With an intake at the front, you end up needing a remote air filter, or some sort of S shape tube.
Car Motor vehicle Vehicle Hood Automotive design

Motor vehicle Automotive design Car Automotive air manifold Personal luxury car
 

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Yeah, I prefer our way than that.. Yes, it covers up that beautiful engine, but...
It doesn't have to cover up the engine.

This is mine
Motor vehicle Hood Vehicle Automotive design Automotive exterior
 

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2004 SLK320
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177 Posts
Post #20 shiny T is pretty much what I would've choose, if I was to improve.

On the matter about heat, the fiber...cloth and aluminium, you have the aluminium warmed once and it will still "keep" the fiber underneath heated.

We all know the cooler the air intake, the better. And as mine is SC an intercooler is a must. On that note you seem to have no space for re-routing the air intake, but keeping it cooler as long as you can.
Have you seen this:
View attachment 623647 K-flex, Arma-flex ...who knows what brand you can find in HVAC store near by. The aluminium is reflective for the radiation but the "rubber" is low conductive (can not say if less than the fiber you mentioned) and the "closed cell" structure is a very good insulation (general thing, right).
But it is about 1cm thick, that means space!?! You know better, how much you have, but fiber...cloth plus "rubber" and aluminium reflector... would've been better. Imagine 2 layers of insulation before the house of yours is exposed to heat cold weather outside...plus 1 reflective coating on the outside for the radiation...

And about the Airflow that Turbo mentioned along with thermodynamics we have dynamics of fluids and friction.
The different flow (change of direction) has specific resistance, that means friction, the friction is a heat source (put your both hands together press and slide, is this how you warming up your hands when cold) imagine high speed air flow that has layers, more friction? Why layers?
Well, water was mentioned as fluid and river bed has "slow" motion/speed near the shore and higher flow/current speed/motion in the middle, imagine 2 river beds on top of eachother (mirrored) - there is your air intake, lower air flow on the ends (pipe wall itself) then friction and higher flow in the middle! And one brutal (general term - contrasting speech) out of shape T piece to "force" both air flows clashing first and then going the right way.

Pardon my inaccurate explanation (far from engineering language) just I started 4 am UK time to BHX Airport, to get delayed flight, time on the airport, lack of info... finally started with nice delay, landed at the destination and currently have 2 more hours (out of 6-7 hours - total of 500km bus ride) with nothing but a coffee in the morning...the headache is...the bus stop was to a place that was having only WC working and outside coffee machine...
Regardless of incidentals…great job on this!
 
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