N75 valves....good or bad?
12-17-2003, 06:13 AM
#21
+ input from S4 gurus:
"Stock ECU software isn't as much of a control freak as some people seem to think around here... thats why tweaking the N75, or replacing it, works fine on a stock car. In fact, the chipped software seems just as brain dead... its just got different maps. Thats why something like the "ECS" N75 causes so much trouble on a chipped car -- it appears to trigger the ECU's overboost control mechanism and cause the "pogo" effect with boost."<ul><li><a href="https://forums.audiworld.com/s4/msgs/1219872.phtml">https://forums.audiworld.com/s4/msgs/1219872.phtml</a</li></ul>
12-17-2003, 06:28 AM
#24
Gurus give thumbs down ON A CHIPPED CAR. :)
<ul><li><a href="https://forums.audiworld.com/s4/msgs/1098937.phtml">https://forums.audiworld.com/s4/msgs/1098937.phtml</a</li></ul>
12-17-2003, 06:35 AM
#26
Again, endorsement for stock, no to chipped.
<ul><li><a href="https://forums.audiworld.com/s4/msgs/1492979.phtml">https://forums.audiworld.com/s4/msgs/1492979.phtml</a</li></ul>
12-17-2003, 08:14 AM
#27
So, to summarize, it is allegedly good, but only on a nonchipped 2.7T (?)
Sounds like people with chips saw boost spikes that triggered boost shut-down so it see-sawed the boost.
AUJ has had no bad experience yet. AUJ, could you tell us what the performance difference was? Did you log boost levels? What did it show? How did the boost curve differ from stock? I've read enough to indicate that boost spikes can be undetected if they are very short; and spikes can do a ton of damage.
What worries me is that one chipped car said the performance was fine, but that the boost spikes were scary. Are you saying that the chip pushes boost up, and the N75 pushes it even further; and the combined effect is the problem?
Knowledge is power. Ignorance is bliss. Choose your weapon!
AUJ has had no bad experience yet. AUJ, could you tell us what the performance difference was? Did you log boost levels? What did it show? How did the boost curve differ from stock? I've read enough to indicate that boost spikes can be undetected if they are very short; and spikes can do a ton of damage.
What worries me is that one chipped car said the performance was fine, but that the boost spikes were scary. Are you saying that the chip pushes boost up, and the N75 pushes it even further; and the combined effect is the problem?
Knowledge is power. Ignorance is bliss. Choose your weapon!
12-17-2003, 10:03 AM
#28
I logged in block 204 and noticed about .2 Bar increase across the board. Surging reports have only
been on chipped cars which is related to the non-Audi tuner's boost remapping of the chip; not the valve. My set up is Bosch 114s ( TT BPV which piggie proved to be exactly the same as 110s after a cut down). I chose this mode of tuning for two reasons. The 1st was I wanted torque under 310 ft-lbs to be non-threateningto ZF's stated limits of the 01V Tiptronic transmission. The second was that I have not found a chip tuner that has been able to duplicate the smoothness and drivability of the stock chips. I wanted a non-chip alternative to getting more power because I did not want my small oil line fed K03s (I have an '00) getting overspooled or overheated because some tuner writes a program that rides the knock sensors with unsafe timing and runs bad A/F ratios for more power. So, this valve appeared to be the perfect solution. Audi programming with a little more boost. I logged EGTs as well and only found a mean of about 25 degrees C increase. Much better than the 200 degree increase with some tuner products. I realize this age doesn't appreciate anything short of a full electronic redesign via a chip, but this compromise to today's ideals maximizes performance with an electromechanical valve and the 114s enhanced boost control design addressing the surging issue via higher mechanical design tolerances. It may not be as fast as the 1.2 Bar chips out there that I have run on my 3 prior 2.7Ts, but I was after drivability and smoothness as a priority over max power. The $100 investment on TT BPVs and the UrS4 N75 and the $300 on a custom Borla exhaust has given this project a very happy ending. I am only sharing this discovery because of the pleasing endpoint and will get no benefit if others choose to follow this path. If people want to find out more hands on in depth info, they should call ECS tuning as they are selling this valve and have much more info on the topic than I have acquired for my personal transportation project. 
12-17-2003, 10:15 AM
#29
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I am ready to try this, as soon as you hit 3-400 miles with no CEL
an alternative between to higher power/higher risk strategy.
In addition, any time the car thrown an unrelated CEL - just jam the stock part back in
In addition, any time the car thrown an unrelated CEL - just jam the stock part back in
