I posted a while back about a running issue I was having with my 200 20v. I ran down boost issues, throttle switch, rpm ref sensor, etc, etc. Swapped ecus, and now no issue whatsoever. Reinstalled oe software in old ecu, and had bigger issues than with the MTM II software. Ecu blinked code 2224-overboost. Swapped the new ecu back in, and ran like the champ she is.

Just wanted to report back in case anyone else might experience similar issues.<ul><li><a href="http://forums.audiworld.com/v8/msgs/137011.phtml">Previous AW Post</a></li></ul>

And what was the max boost with the MTM mod? I ask all these questions because I rarely see a PT fail unless it's been whacked at over it's rated capacity routinely. Before you install those chips into the stock ecu, worth thinking about.

Scott J

Max boost with the MTM II is 25 psi. I am using a 'k' wgfv-I noticed a big difference with respect to how the boost 'comes on'. Much more linear in nature IMO. I agree that this would/should be the last item to check given the symptoms I was experiencing, but I had exhausted all the other options.

Then again, the car is almost 18 yrs old with 195k on her...

IIRC on the 200q20vt, MTM II is a 2.5bar PT (22psi) not 25psi you are confessing, that's MTM III with a 3bar pressure transducer. I don't see that many PT's fail, unless something like your 3bar Pressure Ratio repeatedly whacks a 2 or 2.5 bar PT. The stock 200tqECU will have "Bosch 200Kpa" on the PT, and IIRC my HerrMeyer-speak, MTM II should have "Bosch 250Kpa" on the PT, and your 25psi should have "Bosch 300Kpa" on the PT.

My bet is you have a 2.5bar PT, and your overboost code is correct. But, ck the box first.

Scott J

that you can use the stock OE PT. So Jim prolly has the stock one.
I have these same chips &amp; was told that I did not need an upgraded PT to run these chips.
But looks like you do need one.

I have the Ben S software with 2.5PT &amp; it runs great.
I was going to put the MTM chips in the ECU I have the ben S chips in with the 2.5PT to see if there was any difference in them from when I had them in the ECU with a stock PT... but I'm having way to much fun with the car as it sits now :-)

to try and duplicate the issue jurq is having. I just don't care to. Why mess with a good thing? The only other thing jurq's car has that mine does not is his Dalback BPV. I'm running the stock one. And his new 034 intercooler silicone hose.

IIRC my PT nerding from years ago, a Bosch PT has a .1-4.5volt output from 1bar vacuum to 1 bar boost. If a 2.0bar PT is installed in a box, that means at 2bar pressure ratio (~14.7psi boost) applied to the line, the max output from the PT to the board at that level is 4.5volts. By definition, it also means that a 2bar PT can't differentiate between 2 bar and 2.1 bar, or 3 bar. It's all the same = 4.5volts output.

Sooo... If you then whack a 2bar (15psi)PT with 3bar (24-26psi) levels of boost, from 15psi-25psi the ECU programming does not, and absolutely *can not* change any output parameters to the wastegate FV or to the fuel. To the computer ecu 15psi=25psi. I personally have never had the pleasure of seeing 25psi in a 2bar PT 200 ECU. That said, it doesn't sound right to me at all, and that's not my understanding of how MTM did their stage II boxes.

All that said, is it possible, if in fact jurq has been running 25psi thru a 2bar PT, the 2 bar PT is bad? Absolutely, that's almost double it's rated boost capacity!

If indeed this is a 2bar PT with 25psi, to me it's nothing more than first hand accounts that Audi builds one tough turbo motor. The fix to the problem identified seems more basic to me?

More .02 arbitraged thru the peso

Scott J

Because you should be able to without fear something is going to blow up. Geez boys, this is old stuff, like 15yo 10vt stuff. There is absolutely no reason to run outside the boost parameters of the Pressure Transducer. VMAP makes an excellent one, and 2.5bar PT's are easily available from the Scar guys that upgraded to the 3bar PT.

The part that surprises me more than anything, is that anyone runs this stuff, and doesn't know what it is? "Zero issues", does not mean it's right, safe or good. Any modified Motronic ecu running today should be sporting the proper PT for the boost levels of the car. If it's not, I claim it's assuming unnecessary risk (better than calling it a hack I suppose).

Let's apply KISS to this: A 2bar PT can safely measure up to 14.7psi. A 2.5bar PT can safely measure up to 22psi and a 3bar PT can safely measure up to 28psi. If you *exceed* any of these boost levels with a lower PT than the boost you are running, your computer cannot compensate for the difference.


Scott J

And if I don't need to **** can it, I won't.

Oh, and I am NOT one of the guys...

The reason I said that, was there is no reason a 20vt motor with the proper electronics can't be run to redline on a daily basis at full boost. If there is a problem with the chips, I'd sure want to know before I hit the crossover point.

I take all my cars to redline regularly, from my ABT v8 to my 83 urq WX with k24 conversion. I'd also argue, chances are good if there's a problem, it will manifest itself below WOT (closed loop) worse than a fuel dump WOT whack.

Scott J

beneath anyones hood, and the condition of it's motor contents (including ECU) that makes it run.

I have no issues with you red lining your cars, I just have no need to, NOR do I have to prove to you that my car runs fine. I prove that to myself daily, and have proven that to others that KNOW ME as well. Several on this forum have driven it, and a few others on other forums as well. I haven't really heard a complaint from them that my software and or ECU is pooched with the stock PT after driving it. Can't say that I know how many if any have redlined it or not either.

If you knock this girl down, she's gonna get back up...

As the folks I service cars for, *expect* me to know. Anyone should be able to take a 200tq20v in any ecu trim, and run it to redline without the fear of a strike from the Audi Gods.

This isn't anything personal, I could care less how you drive. I made it my point to know everything in my own cars for 15years, even when Ned put a couple bucks worth of resistors in my Mac11 16years back... And on occasion, jump in on these boards to advocate owner knowledge too.

I also think if anyone is running more than 14psi in their turbo car with a 2bar PT, that's assuming risk, and I could care less how it runs or feels. If your ECU can't differentiate between 14 and 16psi, what is it that anyone driving that car 'really' knows?

I confuse easily.

Scott J

...and just go ahead and redline it no matter what the condition of the car may be at that time? I know that you have owned a 5K back in the day. I'm sorry, but that just sounds silly. But on the otherhand a great way to find out some hidden issues and then some quite possibly.

I do find it interesting then since these MTM II chipsets have been floating around that just as of late 'some' talk about PT has come up...one would think it would be common knowledge across the boards no matter what software one is using. Especially on the handful of often used forums across the board for Audi...I'm sure I would have stumbled on it somewhere, besides now.

Then why not push it to redline? If you put in an ecu that adds unknown risk, why run it? "5k in the day"?! I'm gonna save that one! I'm an educator by nature, an audi nerd as my living.

If you take a moment to read *how* I claim a PT works in the ECU, I'm not sure I understand your claim in it's context. If you run a 2bar PT equipped box at 2.1 bar, the ecu can't compensate for the difference, period. Can you make the WOT tables dump more fuel for 2 bar (=4.5v) that will also make it run at 2.1 bar (=4.5v) or 3 bar (=4.5v)? I suppose, but the point is there is no difference in the fuel/timing tables between the two.

Take that more extreme, here we potentially have a 2 bar PT running double the boost level of the PT rating. I will make the claim there is no comfort in that, even if the car 'runs'. I'd use stronger words, but I'm just a boring nerd type.

"Back in the day" I ran a zener-diode ecu that stepped the voltage output of the PT to the board. It was a hack, and the car ran great. That said, I was also one of the first "back in the day" to advocate if you could program the chip to read the output of the PT correctly, it's a better way to skin the cat.

Reading this retroactive approach now, some 14 years after the 10vt boxes, on the 20vt Motronic seems silly to me. Especially since 2.5bar PT are easily available, and VMap PT were developed *specifically* for the 20vt Motronic.

At 171k with the proper chip/PT combination you can run that car to redline. To make the claim that 'all is fine' excepting no WOT runs... Only reinforces my claim that Audi makes a bulletproof I5 turbo motor.

I'm sure I just don't understand your point. I run my 17year old 4.2 motor to redline daily and my 25year old turbo quattro to redline daily as well.

Cheers
Scott J
93 v8 Abt 4.2
and a few turbo cars...