Tuners Rejoice! Free Tuning For M4.4!


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Attention: The first 30 or so pages of this thread are outdated. Please refer to the M4.4 Wikia article where all the relevant information is currently being collated. Before asking any questions p

Crush it.

After alot of testing and rewriting code, we finally got a useful new mod working. As we all know, some time ago my dad Piet found out how to convert to bigger maf housings with the maf factor. Conver

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I'll make a write-up on the logging part. It's a pretty simple script anyway. But I can imagine people would like to receive something that they can just plug in, instead of having to design and solder their own circuitry.

they can still have that, but then there are other such as myself that would rather diy and use/modify the design you created... everybody wins

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they can still have that, but then there are other such as myself that would rather diy and use/modify the design you created... everybody wins

Just a little patience, it will be allright....

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So... big oops today. Checking for vac leaks I accidentally bumped the Bootloader switch while the car was running. Car died and doesn't start. Reflashed ecu and nothing, Reflashed a spare ecu and still nothing. Didn't work with the spare before flash either when I know its worked before. Clueless as I know you aren't suppose to touch the switch while the car is running. (I don't think any one has done this) DD and work tomorrow so I'm lost. Anyone got any ideas? Car just cranks and cranks.

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So... big oops today. Checking for vac leaks I accidentally bumped the Bootloader switch while the car was running. Car died and doesn't start. Reflashed ecu and nothing, Reflashed a spare ecu and still nothing. Didn't work with the spare before flash either when I know its worked before. Clueless as I know you aren't suppose to touch the switch while the car is running. (I don't think any one has done this) DD and work tomorrow so I'm lost. Anyone got any ideas? Car just cranks and cranks.

What pins does the bootloader short out? That's what you need to look at

I don't know for sure that that would change with a different MAF table, load does decrease in the upper rpm's, even though HP does not :D . It will be interesting to log once I have a table for the 3.75" ID housing

10170759_10151931795191370_218847377_n_z

Many thanks to Piet, Justus and Maarten for the formula, lessons and help with Excel :) I have a preliminary table developed for the 3.75" ID inlet/MAF housing. 2322kg/h max flow

Screenshot2014-04-11181959_zps0e3022b8.p

Stock area (2.5" ID housing) is 4.9063"sq, area of 3.75" ID housing is 11.0412"sq which is 125% larger? 2.2504x larger? >Last time I tried to figure out this math, I failed

I have loaded it into a bin, so this weekend I will test it out

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Hussein, do you have a air straightner pre MAF?

I do. Bosch supplied version in the current housing, and the honeycomb version in the aluminum 3.75" ID housing going in.

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Hussein

I did some recalculations and an estimate of the conversionfactor of 2.57 for the 3.75" ID instead of 2.7) with a mass airflow of 2123 kg/hr at 5 volt might be somewhat closer. (it's good to realise that it is still an estimation though, but it might be a good starting point to begin with, tweaking the conversionfactor until a good result is obtained). it may varies with the exact position of the sensor in the mafhousing.

Just with lowering or raising the factor you should come up with a good result. (if fuel trims are raised try raising the factor and vice versa)

I'am very curious what your results will be!!

The other MAF's i have measured, the values of the 3.75" MAF are calculated from this, so it is very interesting for me to know how far off (or hopefully not) these values will be.

Interesting to know is that the 3" audi maf, the only maf without an airstraightener, is the only maf i measured that won't exactely fit in ( the caculations). So the airstraightener could really play an important role.

The suface area of a 3.75 is 2.25 times that of a 2.5 inch maf so 125% bigger, that's correct.

Edited by Piet
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Thanks, Piet

I redid the table using the factor of 2.57

I'll give it a try. I may have to reduce the curve below 1.2v to closer to your 2.75" table, as that is the area that caused much problems with warmup in freezing ambient temps.

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Also in that area the ouputvoltage will drop significantely with the substantial bigger 3.75 ID maf, with a tendency to go to lean.

You will have to tweak it a bit until you see the same airflow in your log as before, I think, in that area.

GOOD LUCK!

Edited by Piet
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Did some more testing with the 3"ID audi maf which would't fit in the calculations.

This is a 3" audi maf of with I first centralized the sensor with a shim of 5mm between the sensor and the mounting flange for the sensor, the maf has no airstraightener.,

With several measurements in the car with the audi maf in front of the airbox I found a conversion constant of 1.43, not that much bigger then the conversion constant of 1.34 I found for the 2.75"ID S90 maf.

The conversion constant according to calculations in comparison with the stock, S90 and 3.25ID Mafs should, however, be 1.6.

So, I took the test and mounted the audi maf as primary maf and drove with it.

First with the conversion constant of 1.43, with this the LTFT_P raised.

Next I tried the calculated constant of 1.6 and that one appeared to be spot on, got the same LTFT as with the stock 850.

Apparantly the lack of an airstraightener while mounted before the airbox is of greater influence then when mounted in the normal primary maf position.

That's what probably made the measurement off.

I have so say that with the audi maf in the normal position and with the right constant of 1.6 the fuel trims were ok but idling was quite rough due to the absence on an airstraightener.

Edited by Piet
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Thanks for the additional research, Piet.

That MAF did come with a straightener, I just didn't send it as I was using it with my aluminum housing...

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3" ID compared to 3.75" ID

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Installed. Various lines may need some adjustment once it's settled in.

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Initial tests with the 3.75"ID housing & 2.57 conversion factor table are pretty good.

First start - this is the values I was seeing with the 3" modified MAF table - never got much closer to zero on the I trim, or the PL trim.

Screenshot2014-04-12154721_zps0af81f7f.p

since it felt quite good - I did a little low speed WOT - 1392.75Kg/h / 387g/s around 6800rpm. Have to see what it records up over 8K rpm. Load still drops off after peak torque, as I would expect.

Screenshot2014-04-12153851_zps2a853fae.p

after a few miles gentle driving - PL trim varies +/- 2, so significant improvement there, and I trim is around 20, so that seems very good, so far.

Screenshot2014-04-12154616_zps092512ca.p

Cold start/warmup will the be acid test, since that's where I've had all the problems in the past.

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