skandalis,

I never doubted what your car was reading. I believed you all the time, I just didnt know why your car was running different pressure than ours. Turns out they are the same. Good to know though that APR's software runs less boost than GIAC and the car's still faster.

That was the exact reason i boost tested my car...i was faster than other 997TTs here and i was running 1bar while others 1,2 or 1,3bar...

Matt, I have a suggestion that will easily put the entire boost issue to a rest. Next flash you guys do or during the next dyno session, bring along a mechanical boost gauge (cheap Autometer gauge will do) and just tap into a vacuum line coming out the intake manifold. It doesn't have to be installed a all. Someone can just stand there and hold it or use a long enough line to bring into the cabin (even if its outside the vehicle) and just look at it in real time. It's really an easy and cheap solution to one of the central arguments surrounding the APR tune.

I'm weary of trusting a stock boost gauge as they are notorious (at least in other car makes) for showing inaccurate readings. Going by what has been said in this thread and others I suspect the factory gauge (and in turn maybe even the ECU datalogging) shows a given boost not matter what the actual peak boost is.

Now, I realize that skandalis reports that he used an actual gauge and saw 1 bar, but as that did not quench the discussion (on the contrary it stoked the fire) then it falls to the hands of APR's dealer on these forums.

Perhaps i can do that and video tape it...at first time with mech gauge max boost was 1,05bar...

For the benefit of everyone here (particularly Matthew GMP and Skand) the cars boost gauge will only read up to 15 psi in both SC and normal modes. It will read up to 1.2 bar in SC and 1.0 in normal. How do I know this? Ive tested the gauge in my own car with my Proto tune. Dont forget that APR has already specifically said there is only one tune setting hence the boost gauge defaults to the normal mode gauge setting.

Skand i also think you are imagining a different throttle sensitivity in SC as how can that be when APR have only the one tune setting. APR would again need to reclarify this point else perhaps some of your customers Matthew can help here with their experience....you too as well as you say you have driven these cars.

Matthew if your customers are telling you that they had higher boost readings with Giac and other tunes then they are seeing imaginary things.

I have been advised by my tuner that there is a separate program available from a manufacturer (AA- Automobilt technic) that will allow the cars boost gauge to read higher. To his knowledge this program is not part of anyones tune and is available as a separate modification to the vehicles ecu softaware.

There is no new revelations here at all with the thinking now that APR does use only one bar boost. Skand at this stage you are not correct with the 1 bar up until such point you provide hard copy to prove it. Again, if you prove it then that allows the question to be shifted back to APR for answers as they have been specific with this tunes boost details.

Please dont forget that APR HQ clearly and formally stated that this tune uses from 18 to 20Lbs boost to acheive its maximum output.

Ok so is there another way to tell what its really making PSI wise? Durametric?

As per my suggestion above, the easiest would be with an actual mechanical gauge.

Matthew you already know this is the best way. The cars gauge with the APR tune will only ever show 1 bar regardless of which stting you are in.

And also a durametric data log too.

leousm thankfully you are on the same page. Its nice to know someone out there is actually paying attention. Reps to you for that.

Anyone care to describe how this is done?

To be honest bbywu i have no idea on how to do that. When i spoke with Todd K on this boost issue it was he who said a durametric data log will show the boost. Thats why i have asked for one way back. Skand has said he has done one of these previously so he must know how its done too i imagine, although in saying that he never furnished the hard copy. I will email Todd and ask for further clarification and come back on that tomorrow morning. Todd also gave me the info on the company that produces the software to get the cars gauges to show the true boost readings for cars with tunes producing boost levels beyond 1.2 which as he said applies to pretty well every tuner he was aware of.

Boost on demand during WOT is not directly measured.

You need to calculate the value based on ambient atmospheric pressure using Durametric v5 (6.0B variable seems to be labeled differently.)

"Boost pressure of sensor" is an actual value, and it is displayed in mbars. Ambient pressure needs to be recorded as a constant. Under acceleration, the sensor reading needs to b e corrected with the ambient pressure constant.

ie

990 mbar at idle

At 6734 RPM WOT, I will record 2178.75 mbar.

2178.75 - 990 (reading at idle) =1188.75 mbar / 1000 = 1.18 BAR

Now...the real question is how accurate is the Y pipe sensor?

Its all a little dutch to me. Todd didnt elaborate his procedure to me so im assuming he knows a way to do it. He also has all the cables, piwis etc etc so i'll ask him exactly how he sees it as being done. If he gives me an email answer by tommorow i'll let you know. If i get up early tommorow morning i'll phone him up.

Crazy... wouldnt you think APR would help out here!! Its their tune. They have all the equipment. Surely they have hard copy data to draw upon from their own testing and development of this tune. Matthew i think its time you as an official APR agent stepped up and put the pressure on APR to clear this mess up once and for all. They simply cannot say they have retained no data on this tune and if they do..well.....that pretty says it all for me.

This getting way beyond a joke.

And Matthew, dont worry about moderators deleting any of APR's posts. Why would any one do that when so far everything they have come up with is flawed nonsense. Retaining this garbage for everyone to see would only helps those board sponsors with tune products out.

My understanding is the Y-pipe sensor is fairly accurate at least from what my tuner has told me in the past. Do you think otherwise?

I feel they are pretty accurate, however, they are a bit sluggish in sensing changes.

Thanks. I've never recorded my boost level. Maybe I'll do that. I don't have SC, so it will interesting to see what I'm running.