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Done my MAF relocation this afternoon. Not sure if I'm have a pulley upgrade but a cheap & easy mod to do, so why not!!! Cost £59 ($90) for the post facelift pipe and after some cutting of the original pipe, the mod was done. Not sure if I've noticed a difference yet but time will tell.

If anyone interested, the part number is 1111410904. The only peice of this part number needed is the clamp that goes onto the intercooler, the flexible hose and the rest comes from the cut done "old" pipe.
 

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sorry if this is a noob question ...

very new to these forums so sorry if this has been answered elsewhere but is it necessary to relocate the MAF on the post facelift version?

I have a 2004 230 and was wondering if this was something I should be looking at doing?

many thanks

Scitru
 

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very new to these forums so sorry if this has been answered elsewhere but is it necessary to relocate the MAF on the post facelift version?

I have a 2004 230 and was wondering if this was something I should be looking at doing?

many thanks

Scitru
No you do not need to do relocate the MAF.
 

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MAF relocation accomplished:

I did the relocation and have driven the car now for about a week, so I am convinced that the improvement is not a figment of my imagination.
The acceleration is much smoother now and when driving slowly the car does not jerk back and forth. All in all, I would say the improvement is definitely worth the time and small expense.
As an aside, I wondered why there is an improvement, since the only difference is the volume of air in the tube between the MAF and the butterfly valve.
After a little thought, I have the opinion that the volume of air introduces a resonance effect that fools the MAF into thinking there is more or less air flowing into the engine. This could account for the "bumpy" acceleration experienced before the mod. Why it fixes the jerking is not clear to me.
I wonder if anyone has any knowledge on the subject?
Chuck
 

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I believe that it is rather turbulence than resonance that causes "bumpy" acceleration. Any bend or change in pipe diameter and/or shape will create some turbulence in the flow and the flowmeter (MAF ) can be "fooled" to give a wrong measurement and since the turbulence is not stable the reading may be going up and down even if the air flow is actually constant. I suppose that this could even cause your jerking.

To avoid such errors, it is good engineering practice to install flowmeters with a certain lenght of so-called "straight run" piping both up- and downstream. The requirements of straight run varies between different flowmeters but around 5-7 pipe diameters upstream and a little less downstream seems common. So if the air pipe is 3" in inner diameter, there should preferably be no bends or other flow disturbances 15-20" upstream and 10-15" downstream - difficult to adhere to in an engine bay! I guess the basic philosophy is: little is better than nothing and do the best you can. As I recall, there is a perforated plate in front of the MAF in our cars - this may assist in reducing turbulence over the MAF.

I hope the above made a little sense.

Thanks for posting your experience with this mod. I have some bumpy acceleration myself and will be doing this at some point (probably when they start pouring salt on the roads here in DK :mad:)

Raindog
 

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Cause of MAF errors:

Hi Raindog:
Thanks for the precise explanation, I like to know why things are the way they are and your analysis is very illuminating.

I am originally from Chicago Illinois, where we put salt on the roads and now the damage to the infrastructure is obvious, add to that the rusting of the automobiles. The actual cost of using a "cheap" solution is not so cheap after-all.
Thanks again for your comments.
Chuck
 

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I am happy you found my words illuminating.
It seems we think alike on many points and I certainly agree with your analysis on the "cheap" solution of salt on roads.
 

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Part number for stock pipe

Any one know the part number for the stock pipe that you modify during the maf relocate process? Looks like mine was botched and need to order a new stock pipe. Thanks!
 

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Part number etc..

The part number is: 1111410904.
I also bought an extra clamp because the pipe has a flat spot that is a little trouble to seal without double clamping. There is another post on the forum that deals with the relocation and has a lot of pictures etc.
My only comment beyond what he did was you should be careful when cutting the pipe and maybe make more than one cut and then try the fit.
Good luck, I think you will notice a smoother running engine as a result.
Chuck J
 

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Hi Chuck -

Thanks for your response. I am actually looking for the part number for the old piece that is in the SLK before it is modified. The relocation in my car wasn't done correctly and I need to start from scratch. Any chance you have that number? Thanks,

Derek
 
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