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Author Topic: upgrading turbos, keeping same stage 3 tune? (ko4 -> rs6/k24)  (Read 17613 times)
erykv1
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« on: August 08, 2014, 03:00:09 PM »

Hello Nefmoto,

I've asked this question in various forums and PM'd various tuners all with different responses.

If I currently have a k04 tune, and change out the k04 turbos for some k24/rs6 hybrid turbos (keeping everything else the same)... will there be any significant problems?
I was under the impression that the n75 would control the boost levels, and of course there would be some power left out on the table. I am ok with that as my block is not built, and I rather not have k04's running at their limit.

What is the verdict on this?

Thanks!

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phila_dot
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« Reply #1 on: August 08, 2014, 04:11:54 PM »

Charge pressure control will not even be close.
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erykv1
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« Reply #2 on: August 08, 2014, 04:19:41 PM »

Could you elaborate?
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nyet
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« Reply #3 on: August 08, 2014, 05:25:51 PM »

The PID will have to be retuned.
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erykv1
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« Reply #4 on: August 08, 2014, 05:55:12 PM »

Will i damage anything running the k04 tune?
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ddillenger
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« Reply #5 on: August 08, 2014, 06:20:55 PM »

Will i damage anything running the k04 tune?


Depending on what K04 tune it is, absolutely. If it was tuned to ride the map the ecu won't know it's overboosting. The SRM's running K04 level wastegate duty cycle will be 30+ psi.
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erykv1
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« Reply #6 on: August 08, 2014, 07:23:48 PM »

It is an 034 motorsports tune.

So the n75 on the k04 tune wont be able to regulate boost levels correctly?

Is there any way i can modify this tune myself for rs6 wastegate duty cycle?
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_nameless
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« Reply #7 on: August 08, 2014, 07:59:46 PM »

you can use a manual boost controller in parallel to control over boost... its not the right way but its a cheap effective way to avoid a retune if thats what your trying to do by the sound of it.
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erykv1
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« Reply #8 on: August 08, 2014, 08:35:36 PM »

thanks Marty.

I want to get a proper rs6 tune, but not until my block is built. I do not want to throw a rod.

When you say run a MBC in paralle, i would run it like this pic?

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_nameless
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« Reply #9 on: August 08, 2014, 08:40:43 PM »

thanks Marty.

I want to get a proper rs6 tune, but not until my block is built. I do not want to throw a rod.

When you say run a MBC in paralle, i would run it like this pic?


yes sir
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ddillenger
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« Reply #10 on: August 08, 2014, 09:31:15 PM »

There is no risk to your rods with a proper tune and pump gas on the SRM's.
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Lost
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« Reply #11 on: August 09, 2014, 12:26:38 AM »

Depending on what K04 tune it is, absolutely. If it was tuned to ride the map the ecu won't know it's overboosting. The SRM's running K04 level wastegate duty cycle will be 30+ psi.

34psi too be precis.
A friend of mine did it, and at first run he blew his clutch.
Than the tuner here in Sweden did something that is absolutely Nono.
He reached down and turned on the wg screws a couple of times, and fucked it all upp.
The car is impossible too tune now.
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erykv1
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« Reply #12 on: August 09, 2014, 03:12:38 AM »

There is no risk to your rods with a proper tune and pump gas on the SRM's.

I would love that but due to time constraints I need to have my car running and i dont think ill know enough about nefmoto to have a proper tune. Im trying to learn as much as i can
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diagnosticator
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« Reply #13 on: August 25, 2014, 12:05:10 AM »

Since the K24/26 hybrid turbos are larger machines, running on K-04 boost maps, should result in about the same boost pressure as the K-04s with slower spool up response time, not excessive boost. The boost controller is a 3 mode PID controller, (Proportional/Integral/Derivative) with actual boost pressure feedback for comparison to the requested boost, for offset/rate/reset response to drive the N75 control pressure output value accordingly. the N75 control voltage PWM duty cycle is adjusted by the PID controller output to achieve the necessary boost pressure and associated torque development.  Therefore I don't believe there is any risk of excessive boost pressure or out of control boost regulation. With torque demand base engine management two main factors are used as inputs for boost pressure control, the MAF meter output is used for engine load determination, and the MAP sensor output is used for boost pressure measurement. Boost pressure is one of the main torque control variables used by the ECU to match torque achievement with the sum of the torque demands at any instant. If the ECU uses drive by wire throttle, the engine management is based on torque demand. Mechanical  throttle control uses a different boost control model in the ECU software, but is also a PID controller  configured in software. In the specific boost pressure control  for mechanical throttle control, the larger turbos running with  K-04 tune, would most likely not boost as much as the K-04s due to the larger turbine and reduced spool up response. Given enough time, the larger turbos should develop about the same boost as the K-04s. I don't know of any way the larger K-24 based turbos could accelerate out of control, developing excess boost pressure when controlled by the K-04 tune, with everything operating normally.
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ddillenger
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« Reply #14 on: August 25, 2014, 12:19:42 AM »

Since the K24/26 hybrid turbos are larger machines, running on K-04 boost maps, should result in about the same boost pressure as the K-04s with slower spool up response time, not excessive boost. The boost controller is a 3 mode PID controller, (Proportional/Integral/Derivative) with actual boost pressure feedback for comparison to the requested boost, for offset/rate/reset response to drive the N75 control pressure output value accordingly. the N75 control voltage PWM duty cycle is adjusted by the PID controller output to achieve the necessary boost pressure and associated torque development.  Therefore I don't believe there is any risk of excessive boost pressure or out of control boost regulation. With torque demand base engine management two main factors are used as inputs for boost pressure control, the MAF meter output is used for engine load determination, and the MAP sensor output is used for boost pressure measurement. Boost pressure is one of the main torque control variables used by the ECU to match torque achievement with the sum of the torque demands at any instant. If the ECU uses drive by wire throttle, the engine management is based on torque demand. Mechanical  throttle control uses a different boost control model in the ECU software, but is also a PID controller  configured in software. In the specific boost pressure control  for mechanical throttle control, the larger turbos running with  K-04 tune, would most likely not boost as much as the K-04s due to the larger turbine and reduced spool up response. Given enough time, the larger turbos should develop about the same boost as the K-04s. I don't know of any way the larger K-24 based turbos could accelerate out of control, developing excess boost pressure when controlled by the K-04 tune, with everything operating normally.

Best case scenario:

Boost will overshoot, the throttle will close, you will hit limp mode. The issue isn't with the turbos so much as its with the fact that the K24's use actuators that are 2-3 times stiffer than regular K04s.

Add to that most tuners disable, or severely numb overboost detection, and the fact that you're already near the map limit so there isn't enough headroom to sense an overboost condition, let alone for the PID to work, and you are asking for trouble.

Worst case scenario (and the one that will likely occur)

Boost will overshoot. You exceed the map limit so the ecu cannot accurately detect an overboost condition. It sees 22psi and is happy. It continues to allow the N75 to run at 85 percent duty cycle (which, for the typical K04 is 21psi). 85 percent duty cycle on the K24's is closer to 32psi.
« Last Edit: August 25, 2014, 12:24:10 AM by ddillenger » Logged

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