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Author Topic: Tighter wastegates  (Read 26256 times)
phila_dot
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« Reply #30 on: August 21, 2013, 11:28:12 AM »

I think most people here are still getting confused about WG cracking pressure and preload.... changing the preload (shortening the stroke) doesn't actually change the cracking pressure on the WG as much as effectively shorten the WG arm travel and possibly causing higher EGTs due to a half open WG flap.

China actuators cranked all the way FTW
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NOTORIOUS VR
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« Reply #31 on: August 21, 2013, 11:51:46 AM »

China actuators cranked all the way FTW

I wouldn't have it any other way Tongue
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Bische
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« Reply #32 on: August 21, 2013, 12:54:19 PM »

It has alot to do with VE also.

Same turbo, same 18psi actuator on 2 different 1.8t's:
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automan001
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« Reply #33 on: September 10, 2013, 08:37:47 AM »

Find a column (for a given RPMs, I chose to hone on it at 4k and 5k) where cell value starts exceeding value from PSPVDKUG table as you move towards right.
I think if we choose the threshold column (of column where cell value starts exceeding value from PSPVDKUG) in that way, ECU will use it even when vpssplg_w is slightly less (but greater than axis value of previous column). Taking this into account, shouldn't we take axis value of previous column and make all scalings basing on it? Then ECU would go towards WOT & PID regulation only when vpssplg_w would really exceed the choosen threshold pressure ratio. There is almost no difference which column to take as basis, but IMO choosing and scaling previous column to the column where cell value starts exceeding value from PSPVDKUG makes the pressure threshold more sharp and exact.
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julex
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« Reply #34 on: September 11, 2013, 06:51:01 AM »

I think if we choose the threshold column (of column where cell value starts exceeding value from PSPVDKUG) in that way, ECU will use it even when vpssplg_w is slightly less (but greater than axis value of previous column). Taking this into account, shouldn't we take axis value of previous column and make all scalings basing on it? Then ECU would go towards WOT & PID regulation only when vpssplg_w would really exceed the choosen threshold pressure ratio. There is almost no difference which column to take as basis, but IMO choosing and scaling previous column to the column where cell value starts exceeding value from PSPVDKUG makes the pressure threshold more sharp and exact.

I can't concentrate today so I don't get your point, sorry. Easiest way to redo the table to get it to work is just redo X-Axis with your wastegate cracking pressure to replace stock cracking pressure. This has to be done regardless of any other changes you want to make as the compression ratios in x-axis are only suitable for very low cracking pressure.

If you want to alter the table otherwise, go ahead but the X-Axis alterations have to be done anyway.
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automan001
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« Reply #35 on: September 11, 2013, 08:47:29 AM »

the X-Axis alterations have to be done anyway.
You are absolutely right. The question was raised about which point of X axis better suits as base point for rescaling of the whole X axis for new WG cracking pressure.
On my opinion (let's discuss it) it's better to choose previous point of X axis (from previous column), the point where cell values haven't started to exceed the PSPVDKUG threshold yet. In other words, this has to be right-most column where cell values still do not exceed PSPVDKUG. Because our goal is to define in X axis exact threshold (= WG opening pressure) below which ECU doesn't go WOT. This means in the cells under choosen point of X axis you still have to see cell values which do not exceed PSPVDKUG. Remember how ECU searches axis values, it finds the least greatest value. Therefore if in column with your new WG cracking pressure there will be cells with values greater than PSPVDKUG, ECU will go WOT earlier, when vpssplg_w is less the axis value.
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20VTMK1
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« Reply #36 on: October 08, 2013, 12:18:13 PM »

From what I understand by reading the installation instructions is the cracking pressure on the Tial gates is ~18.5 psi, and that is what you are suppose to verify and set it to using a dial indicator and a pressure tester (which is what I did before installing them).  With it setup like that I saw a base boost of approx 22 psi w/ 0% WGDC on the N75.

I think most people here are still getting confused about WG cracking pressure and preload.... changing the preload (shortening the stroke) doesn't actually change the cracking pressure on the WG as much as effectively shorten the WG arm travel and possibly causing higher EGTs due to a half open WG flap.


I did exactly this on the bench with my spare K04-23 , the stock actuator cracked open at 4 psi ! And this was a new actuator from BW ! I verified the results with a second KKK actuator for this turbo and the same . Now this is 0.3 bar , so 1030/1300 = 0.792 , which is where the first point over VDKUG appears ... Correct ?
« Last Edit: October 14, 2013, 01:19:28 PM by 20VTMK1 » Logged
20VTMK1
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« Reply #37 on: October 08, 2013, 12:31:29 PM »

You are absolutely right. The question was raised about which point of X axis better suits as base point for rescaling of the whole X axis for new WG cracking pressure.
On my opinion (let's discuss it) it's better to choose previous point of X axis (from previous column), the point where cell values haven't started to exceed the PSPVDKUG threshold yet. In other words, this has to be right-most column where cell values still do not exceed PSPVDKUG. Because our goal is to define in X axis exact threshold (= WG opening pressure) below which ECU doesn't go WOT. This means in the cells under choosen point of X axis you still have to see cell values which do not exceed PSPVDKUG. Remember how ECU searches axis values, it finds the least greatest value. Therefore if in column with your new WG cracking pressure there will be cells with values greater than PSPVDKUG, ECU will go WOT earlier, when vpssplg_w is less the axis value.

What to do if from stock in PDKSD , all values already exceed VDKUG ? CWPLGU is set to zero ?

Comments highly appreciated - thank you
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nyet
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« Reply #38 on: July 15, 2015, 11:06:59 AM »

What to do if from stock in PDKSD , all values already exceed VDKUG ? CWPLGU is set to zero ?

Comments highly appreciated - thank you


bump
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