Do i need to change the r201 in my aan ecu

[UrS4boy]

Again, apologies for being so pig-headed. You were right.

[prj]

Phew, I was starting to get worried
If you look at the compressor map and assume equal flow with only a change in pressure ratio (as I graphed it), then you will see that the turbo efficiency is affected by less than 1% as well so IAT difference will be negligible.
And this is with screens completely removed. I'd assume the difference is less with the honeycomb in place...

[UrS4boy]

Just to illustrate how little 6 inches of water is:
1 inch of water is 0.036 psi or 0.00248 bar.
6 inches of water is 0.216 psi or 0.015 bar. .

I really have to apologize. . My eyes read "inches of water" but the brain thought "inches of mercury (Hg)" which is obviously more significant (S.G. of Hg is 13.546 compared to water a 1.0). So when I checked your math this morning (based on 1 cubic ft. of water (i.e. 1 ft of water on one square foot of solid surface (144 sq. inches)) weighing 62.4 lbs), one inch of water is as you say, 0.036 lbs/in2 (psi) and 6" is only 0.216 psi. The light bulb *FINALLY* went on. Sorry. As you said, that is not significant. My mercury-addled brain was thinking closer to 3 psi (2.93 psi) which would have been significant.

Thanks for the extra effort to kick the mercury out of my brain.

Now my brain hurts. I think I might have to go see a brain specialist, maybe these guys:

http://www.youtube.com/watch?v=IIlKiRPSNGA

[prj]

Just to illustrate how little 6 inches of water is:
1 inch of water is 0.036 psi or 0.00248 bar.
6 inches of water is 0.216 psi or 0.015 bar.

Here is the compressor map of a K24-7000 on a chipped car boosting 1.4 bar with two characteristic lines plotted with 0 pressure drop and 0.015 bar pressure drop:


Here is the difference in % between the pressure ratio at various RPM, assuming a straight 6 inches of water restriction reduction at every RPM (which is of course not true):

RPM      %
2000	1.14
2400	0.98
2800	0.8
3200	0.62
3600	0.63
4000	0.64
4400	0.66
4800	0.67
5200	0.7
5600	0.71
6000	0.73
6400	0.75
6800	0.76

Maybe now you see how that article is completely wrong?
Your boost is going to oscillate way more than 0.015 bar between pulls, and there is no way in hell you are getting 28% increase in acceleration from losing 6 in/h2o pressure drop.

[UrS4boy]

No sense arguing with ein Besserwisser.

[prj]

The only one that I *might* buy is No.3, e.g. cooler air temps on the no screen test day. Where did you pull No.1 and No. 2 out of ? Your....***?

From experience of what happens to MAF readings when you pull the screen and because boost control is adaptive on AAN. If you load the car from different spots, you will get different numbers.

You know, I have mapped over 50 of these now, I don't need some bodged internet article to tell me what happens and does not happen with the MAF

P.S. Go into 2nd gear, floor the car at 2000 rpm, record acceleration. Now floor the car at 4000 rpm, record acceleration. Now floor the car a couple times in 5th gear from 2000 rpm, and go again into 2nd and floor it.

[UrS4boy]

The increase of acceleration on that car is because:
1. The MAF underread, so timing was increased and mixture was leaned due to fooling of the ECU.
2. The Boost pid overshot.
3. The test was not carried out in the same conditions.
Not because the screens were removed. That entire article has a lot of wishful thinking.

The only one that I *might* buy is No.3, e.g. cooler air temps on the no screen test day. Where did you pull No.1 and No. 2 out of ? Your....***?

[prj]

But yet you say an AAN runs better with a larger, i.e. less restrictive, MAF.

No, it runs better mostly because the larger MAF can read higher and does not peg.
I also said the RS4 MAF is less restrictive due to a better design, yet it STILL has the normal screen.

[UrS4boy]

But yet you say an AAN runs better with a larger, i.e. less restrictive, MAF.

[prj]

Prj, are you saying that Force = mass times acceleration and Work = Force times distance and Power is the rate of doing work, i.e. Work/unit time, does not apply here and that the increase in acceleration was NOT due to an increase in horsepower?

The increase of acceleration on that car is because:
1. The MAF underread, so timing was increased and mixture was leaned due to fooling of the ECU.
2. The Boost pid overshot.
3. The test was not carried out in the same conditions.

Not because the screens were removed.
That entire article has a lot of wishful thinking.

About maf "restiction": As long as you get the boost you want it doesn't matter. If MAF is to small the turbo has to work harder, but race engines with much smaller restrictor then the MAF is easily producing 500+ hp so you need a lot of HP before the MAF becomes a serious restriction.
Just my $0.02

Thank god at least someone understands what I keep trying to say

[Audi_CQ]

About maf "restiction": As long as you get the boost you want it doesn't matter. If MAF is to small the turbo has to work harder, but race engines with much smaller restrictor then the MAF is easily producing 500+ hp so you need a lot of HP before the MAF becomes a serious restriction.
Just my $0.02

[vidar skotheim]

I have seen the previous owners car in action , and it was extreme fast .. and i have run with this a half year now without problems , mostly street driving ..

[UrS4boy]

I did now, and even with screens removed there is not much difference at all....PS: The acceleration difference in the "Negative Boost" article is just total ********.

From the article http://www.autospeed.com/cms/article.html?&A=0652

RPM..Total Pressure Drop Total Pressure Drop Screens Off.... Improvement
.......(inches of water)......(inches of water).......................

3000....... 10........................10...................... ............... 0%
4000....... 16........................14...................... ............... 13%
5000....... 26........................20...................... ............... 23%
6000....... 32........................26...................... ............... 19%
7000....... 29.6.....................24.8..................... .............. 16%

"...Up until 4000 rpm there was no change - which is to be expected because the flow restrictions at low rpm aren't much anyway. But from there upwards, an improvement could be seen. The peak pressure drop was reduced (and that means the flow improved!) from 32 to 26 inches of water, a 19 per cent reduction. But unfortunately 26 inches of water is still a helluva restriction - I hadn't found and killed the chief honcho negative boost.

But - hell - I'd still made a measurable improvement. Slowly, slowly catchee monk-, er negative pressure. And what I didn't tell you is that last week I measured the actual on-road acceleration of the Audi through second gear. Using an accelerometer, you can measure how hard the car is accelerating every 1000 rpm, giving you a really good picture of what's going on with the actual on-road performance. And did it go better with the airflow meter screens removed, as you'd expect given the reduced pressure drop? Yes it did. At 7000 rpm the car could previously pull 0.25g - with the screens removed that increased 28 per cent to 0.32g. And that new-found top-end grunt was obvious on the road."

Prj, are you saying that Force = mass times acceleration and Work = Force times distance and Power is the rate of doing work, i.e. Work/unit time, does not apply here and that the increase in acceleration was NOT due to an increase in horsepower?

[prj]

It is your choice to believe in fairytales

[vidar skotheim]

Well . my chips are made to a ecu with 19.09kohm between 7 and 25 and rs2 maf. and the chips are made with a lot off work . got 10 pair of chips and the last chip that was maid was working very good on the car that the previous owner of the chips had . He was talking at about 600+ with 2.2 bar boost ..