[Chief Orman]

I know this has been addressed before, but I would be curious to know how much max boost folks are generating from the turbos. According to torque pro I am maxing out at 26.5. My Snow boost gauge is closer to 30 psi. This is with 50/50 water meth, Forge charge pipe and ChipExpress tuning box.

[Thecastle]

Originally Posted by Chief Orman

I know this has been addressed before, but I would be curious to know how much max boost folks are generating from the turbos. According to torque pro I am maxing out at 26.5. My Snow boost gauge is closer to 30 psi. This is with 50/50 water meth, Forge charge pipe and ChipExpress tuning box.

It's going to be variable. Boost is a measure of flow resistance. Measured peak boost will generally change with outdoor temp, humidity and altitude. Basically the engine wants a certain amount of air, and it will increase or decrease the turbos output to meet requested air mass, thus varying the measured air flow resistance in the intake, denser lower humidity air will generally result in lowered boost pressure.

Torque and boost gauges are notoriously inaccurate. Most people calibrate a mechanical boost gauge to get an accurate read.

The stock car peaks at 26.8 but it may do less depending on temperature as the car isn't running to a target boost pressure so much as a target mass air flow. It will vary turbo output to a limit to reach targets maf.

[TDIwyse]

Originally Posted by Chief Orman

... According to torque pro I am maxing out at 26.5. ...

Is this with DWR's Torque PID's, or with Torque's approximation where it uses your VE estimate, engine displacement and MAF to calculate a boost number?

[larrysing]

BPC posted this today:

http://www.e90post.com/forums/showpo...5&postcount=41

[Chief Orman]

Originally Posted by larrysing

BPC posted this today:

http://www.e90post.com/forums/showpo...5&postcount=41

Helpful...thank you. According to DWR's PID I am maxing out at 26.8 psi exactly.

[Chief Orman]

Originally Posted by Thecastle

It's going to be variable. Boost is a measure of flow resistance. Measured peak boost will generally change with outdoor temp, humidity and altitude. Basically the engine wants a certain amount of air, and it will increase or decrease the turbos output to meet requested air mass, thus varying the measured air flow resistance in the intake, denser lower humidity air will generally result in lowered boost pressure.

Torque and boost gauges are notoriously inaccurate. Most people calibrate a mechanical boost gauge to get an accurate read.

The stock car peaks at 26.8 but it may do less depending on temperature as the car isn't running to a target boost pressure so much as a target mass air flow. It will vary turbo output to a limit to reach targets maf.

Any sense of what water meth does to boost pressure? If I follow your logic it seems line spraying water meth in the charge pipe before the IAT would lower boost due to the cooler intake temps.

[QUIKDZL]

Chief, I don't see how spraying water/meth in the intake affects boost pressure at all. Boost is controlled by a MAF sensor (and limited by a pressure sensor) in the intake. If you do anything to change the pressure there, the car will compensate by regulating the wastegate. Spraying w/m in the intake downstream of the MAF sensor will, however, make the air charge denser. Putting more oxygen molecules in the cylinder will allow the tuner to put more diesel molecules in there, as well, since he will be targeting an air/fuel ratio.

If you were to look at an instant in time at the w/m injection point, you might find a static pressure of 25 psi (boost already generated, MAF already reported) in warm, dry air. If you now introduce some w/m, you have added mass and therefore pressure. If the w/m evaporates, you have lowered density at the same mass and volume, so pressure again increases. But you have also lowered the temperature. P1 x V1 / T1 = P2 x V2 / T2. What's the net effect? You won't know without knowing the amount of w/m mix (and the ratio) that evaporates and how much it drops the temperature.

Dynamically, this air column can expand or collapse back through the turbo and MAF sensor, so if the air column expands, the MAF will report lower readings and cause the system to raise the target boost (up to its programmed limit pressure). The opposite is true if the air column shrinks. In this MAF-controlled scenario, you would want the column to expand for maximum power. So you would want to minimize evaporation and temperature reduction (of the w/m) in the intake. You want the evaporation to occur in the cylinder after the valves close!

The best classes you will find are delivered by Professor TDIWyse. Read through his "lectures" in this forum to get a fuller understanding (and appreciation) for all the dynamics involved in our fun little cars.

[TDIwyse]

Originally Posted by QUIKDZL

...
The best classes you will find are delivered by Professor TDIWyse. ...

I yield the indepth analysis of this area to DWR. He's posted some really great technical information on this...

[QUIKDZL]

Thanks for the correction, TDIwyse. I WAS thinking of his posts when I made that comment, although yours are generally at the same elevation. I have learned a lot from both of you, and enjoyed doing it.

DWR, I find you to be a thorough, articulate, and patient teacher (and student). I appreciate your sharing. My omission/mistake was unintentional. TDIwyse, I also appreciate your research, practical applications, and articulate sharing.

[Chief Orman]

Originally Posted by QUIKDZL

Thanks for the correction, TDIwyse. I WAS thinking of his posts when I made that comment, although yours are generally at the same elevation. I have learned a lot from both of you, and enjoyed doing it.

DWR, I find you to be a thorough, articulate, and patient teacher (and student). I appreciate your sharing. My omission/mistake was unintentional. TDIwyse, I also appreciate your research, practical applications, and articulate sharing.

DWR has spilled a good amount of ink trying to educate me on these issues. And it hasn't been for lack of trying on his part. Now that my car is running normally I've been taking a look at the impact of water meth on boost pressure and temperatures. After a couple of high speed runs up to 130 miles per hour it appears that running water meth, using measurements from DWRs Torque Pro PIDs, boosts turbo pressure from 26.8 psi to 27.8 psi...and pre DPF max temperatures only increase approximately 70 degrees from 1218 to 1288. So much for thinking I was going to melt my motor running a 50/50 water meth mix. That said I have two fire extinguishers in my car. finally the car definitely loses top end pull when I am not running water meth.

[Bob@BPC]

Originally Posted by Chief Orman

DWR has spilled a good amount of ink trying to educate me on these issues. And it hasn't been for lack of trying on his part. Now that my car is running normally I've been taking a look at the impact of water meth on boost pressure and temperatures. After a couple of high speed runs up to 130 miles per hour it appears that running water meth, using measurements from DWRs Torque Pro PIDs, boosts turbo pressure from 26.8 psi to 27.8 psi...and pre DPF max temperatures only increase approximately 70 degrees from 1218 to 1288. So much for thinking I was going to melt my motor running a 50/50 water meth mix. That said I have to fire extinguishers in my car. finally the car definitely loses top end pull when I am not running water meth.

What size nozzle are you running?

[QUIKDZL]

That was my question...Bob beat me to it.

[Chief Orman]

3

[Chief Orman]

Originally Posted by Bob@BPC

What size nozzle are you running?

375 ml/min first stage progressive and 625 ml/min power second stage full blast. Snow Power Max kit.

375 starts spraying at 18 psi and 675 at 24 psi...no quenching

[QUIKDZL]

I'll let Bob, DWR, or one of the other experts report the exact number, but I'm betting that "top end pull" you talk about losing when meth is off is because of the 50-60 ponies you lose when the button is off.

[Chief Orman]

Originally Posted by QUIKDZL

I'll let Bob, DWR, or one of the other experts report the exact number, but I'm betting that "top end pull" you talk about losing when meth is off is because of the 50-60 ponies you lose when the button is off.

totally agree

[DWR]

First, Chief believe what you are measuring. It is real.

Second, thanks for the kinds words.

Third, QUIKDSL, no apology needed.

Fourth, why does everyone thing TDIwyse and I look alike, lol?

[TDIwyse]

Originally Posted by DWR

...
Fourth, why does everyone thing TDIwyse and I look alike, lol?

I haven't heard that one ... But I offer a hypothesis that it might be because we're both exceptionally handsome?

[Chief Orman]

Originally Posted by TDIwyse

I haven't heard that one ... But I offer a hypothesis that it might be because we're both exceptionally handsome?

Excuse me while I barf in my pocket