Obervations of ECU controlled wastegate on OM606
Obervations of ECU controlled wastegate on OM606
04-24-2015, 05:17 PM
#1
Out of curiosity, I instrumented the PWM signal driving the variable vacuum valve that, in turn, pulls the waste-gate closed. Effectively this tells me how hard the ECU wants the turbo to work.
Here is what I found:
- Idling while stopped: 100%closed
- Accelerating briskly: 100%closed until speed is reached, briefly opening at each (automatic) shift.
- At higher speed/load: Waste-gate moves according to load.
- Loafing in slow traffic: Varies between 40%-60% based on throttle.
- Quick press of pedal from steady: Snaps closed (100%).
- Quick lift of pedal from steady: 20% closed.
- Decelerating from high speed: 20% closed, moving to 100% closed as vehicle comes to a stop.
It seems like this signal could be used to drive a VNT turbo. Any thoughts?
This post was last modified: 04-24-2015, 05:19 PM by AlanMcR.
This is on the OM606 factory installed in my G-wagen. It uses nearly the same control system found on the 98-99 E300DT. From the exhaust note it seemed like the ECU was playing around with the wastegate quite a bit.
Out of curiosity, I instrumented the PWM signal driving the variable vacuum valve that, in turn, pulls the waste-gate closed. Effectively this tells me how hard the ECU wants the turbo to work.
Here is what I found:
- Idling while stopped: 100%closed
- Accelerating briskly: 100%closed until speed is reached, briefly opening at each (automatic) shift.
- At higher speed/load: Waste-gate moves according to load.
- Loafing in slow traffic: Varies between 40%-60% based on throttle.
- Quick press of pedal from steady: Snaps closed (100%).
- Quick lift of pedal from steady: 20% closed.
- Decelerating from high speed: 20% closed, moving to 100% closed as vehicle comes to a stop.
It seems like this signal could be used to drive a VNT turbo. Any thoughts?
04-25-2015, 12:48 AM
#2
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
Seems pretty perfect but only trying will decide.
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
04-25-2015, 01:43 PM
#3
I'll probably try to fit a GTB2260VKLR if i can get one cheap.
I will also try the EGR-Delete mod and potentiometer fuel mod.
Or maybe remap/chip if the local tuning guy can do it.
As long it dont throws fault codes i will be happy.
I also want to try this on a W210 300TD.
I'll probably try to fit a GTB2260VKLR if i can get one cheap.
I will also try the EGR-Delete mod and potentiometer fuel mod.
Or maybe remap/chip if the local tuning guy can do it.
As long it dont throws fault codes i will be happy.
04-27-2015, 09:31 PM
#4
(04-25-2015, 01:43 PM)lajuz I also want to try this on a W210 300TD.I've long ago removed the EGR, the plumbing and gutted the mixer. This is challenging on the G300 because the ECU actually measures the movement of the EGR valve. I built some electronics to fool it (design available for free, for anyone who wants it).
I'll probably try to fit a GTB2260VKLR if i can get one cheap.
I will also try the EGR-Delete mod and potentiometer fuel mod.
Or maybe remap/chip if the local tuning guy can do it.
As long it dont throws fault codes i will be happy.
Just this weekend, I tried the resistor fix (on the IP). Even set at 7K ohms, it provided a nice boost in hill climbing power. That extra power is addictive! 7mm IP plungers are getting tempting.
This post was last modified: 04-27-2015, 09:34 PM by AlanMcR.
(04-25-2015, 01:43 PM)lajuz I also want to try this on a W210 300TD.I've long ago removed the EGR, the plumbing and gutted the mixer. This is challenging on the G300 because the ECU actually measures the movement of the EGR valve. I built some electronics to fool it (design available for free, for anyone who wants it).
I'll probably try to fit a GTB2260VKLR if i can get one cheap.
I will also try the EGR-Delete mod and potentiometer fuel mod.
Or maybe remap/chip if the local tuning guy can do it.
As long it dont throws fault codes i will be happy.
Just this weekend, I tried the resistor fix (on the IP). Even set at 7K ohms, it provided a nice boost in hill climbing power. That extra power is addictive! 7mm IP plungers are getting tempting.
04-28-2015, 05:36 AM
#5
u seem to be more on the electronics than i do, so the million dólar question???
I´m on the mechanichal IP , and i can say that me and my friends we kind of can make what ever pump delivery we want ,
but i was asked by somebody to change elements in a EDC pump, something i did not done.
and the reason is the "Rack position sensor" like many theres no way of doing something if u can´t do it well.
Do u have any idea on how to measure the "rack position" , usually the actuator can be moved with a power source of variable intensity, at 7volts the actuator should be at maximum position, and it starts to move at 2v.
the hell is with the position sensor , how can i know where it is, well a easy way of knowing.
rregards.
FD,
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Alan, just a question,
u seem to be more on the electronics than i do, so the million dólar question???
I´m on the mechanichal IP , and i can say that me and my friends we kind of can make what ever pump delivery we want ,
but i was asked by somebody to change elements in a EDC pump, something i did not done.
and the reason is the "Rack position sensor" like many theres no way of doing something if u can´t do it well.
Do u have any idea on how to measure the "rack position" , usually the actuator can be moved with a power source of variable intensity, at 7volts the actuator should be at maximum position, and it starts to move at 2v.
the hell is with the position sensor , how can i know where it is, well a easy way of knowing.
rregards.
FD,
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04-28-2015, 05:51 AM
#6
(04-24-2015, 05:17 PM) pid=\72783'Overall, it seems to manage the waste-gate based on load, the only exception is the slow traffic mode where it seems to be using the waste-to build back-pressure to enhance EGR flow.
- Idling while stopped: 100%closed
- Accelerating briskly: 100%closed until speed is reached, briefly opening at each (automatic) shift.
- At higher speed/load: Waste-gate moves according to load.
- Loafing in slow traffic: Varies between 40%-60% based on throttle.
- Quick press of pedal from steady: Snaps closed (100%).
- Quick lift of pedal from steady: 20% closed.
- Decelerating from high speed: 20% closed, moving to 100% closed as vehicle comes to a stop.
It seems like this signal could be used to drive a VNT turbo. Any thoughts?
i´m not contesting your find´s , just to be clear on that.
i´ve been looking at the vac schematics on the w202 2.5 TD wich comes with a 605.96X and a gt25 WG.
by looking at the schematics, theres no way that ECU can control the waste gate partially open. and when the engine is in low idling the waste gate is open.
when the engine increases speed at certain point it closes. and will stay closed depending on the EGR protocol.
observation of this car, basically in this particular car, the waste gate or it is closed or it is open. but there are times when it is forced to open by exaust pressure, and in this case is when Max boost is reached around 3k rpm, and from that point on it opens more or less depending on load, but this openig is forced by EGP, instead of the actuator.
what i suggest is for u to observe the vac actator for the waste gate, it is suposed to be a 2 wire actuator, or it can be a double device
with 4 wires, u can shunt a lamp to it and take it inside the car , and watch the lamp lighting, if for any reason your car is able to open partially the waste gate this will be by means of pulses, and in this case u´ll see the lamp blinking.
regards
FD,
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(04-24-2015, 05:17 PM) pid=\72783'Overall, it seems to manage the waste-gate based on load, the only exception is the slow traffic mode where it seems to be using the waste-to build back-pressure to enhance EGR flow.
- Idling while stopped: 100%closed
- Accelerating briskly: 100%closed until speed is reached, briefly opening at each (automatic) shift.
- At higher speed/load: Waste-gate moves according to load.
- Loafing in slow traffic: Varies between 40%-60% based on throttle.
- Quick press of pedal from steady: Snaps closed (100%).
- Quick lift of pedal from steady: 20% closed.
- Decelerating from high speed: 20% closed, moving to 100% closed as vehicle comes to a stop.
It seems like this signal could be used to drive a VNT turbo. Any thoughts?
i´m not contesting your find´s , just to be clear on that.
i´ve been looking at the vac schematics on the w202 2.5 TD wich comes with a 605.96X and a gt25 WG.
by looking at the schematics, theres no way that ECU can control the waste gate partially open. and when the engine is in low idling the waste gate is open.
when the engine increases speed at certain point it closes. and will stay closed depending on the EGR protocol.
observation of this car, basically in this particular car, the waste gate or it is closed or it is open. but there are times when it is forced to open by exaust pressure, and in this case is when Max boost is reached around 3k rpm, and from that point on it opens more or less depending on load, but this openig is forced by EGP, instead of the actuator.
what i suggest is for u to observe the vac actator for the waste gate, it is suposed to be a 2 wire actuator, or it can be a double device
with 4 wires, u can shunt a lamp to it and take it inside the car , and watch the lamp lighting, if for any reason your car is able to open partially the waste gate this will be by means of pulses, and in this case u´ll see the lamp blinking.
regards
FD,
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04-28-2015, 08:35 AM
#7
W124 om606 HX40 finished and it's a beauty 450bhp/456ft-lbs
maxypriest
04-28-2015, 08:35 AM #7In the next week or so I’ll be testing my OM606/HX40 setup on the road. I have installed a GFB boost controller which of course is nowhere near as clever as the the original merc set up, however it will enable me to tune the turbo to get max spool and min flutter. I’ll report back on this.
W124 om606 HX40 finished and it's a beauty 450bhp/456ft-lbs
04-28-2015, 01:24 PM
#8
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
You will not have any flutter on an HX40. That is a big boy Turbo.
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
04-28-2015, 01:46 PM
#9
The ECU monitors all of this by watching the intake manifold pressure. It calculates the pressure it wants, then adjusts the wastegate until it gets that pressure.
On the question of how to monitor the position of the fuel control rod. There are two variable reluctance sensors in the IP. The ECU sends an AC waveform to both and figures out the position by comparing the two responses. That is way out of the realm of amateur electronics. Also, note that the fuel control solenoid is very fast. Supposedly, the ECU can alter fuel volume on a cylinder by cylinder basis below 2000RPM. That is about 160 adjustments/second.
The signal to the vacuum modulator is PWM, or pulse width modulated. This is a square wave, probably around 10kHz. The width of the squares changes from 0% duty cycle to 100%. The vacuum modulator is very slow though. At best it opens/closes in 1/5th of a second. So, as far as it is concerned the signal it is getting is a variable voltage from 0-12v. It turns around and applies an amount of vacuum based on that voltage. So it can move the wastegate into any position it wants. (http://en.wikipedia.org/wiki/Pulse-width_modulation)
The ECU monitors all of this by watching the intake manifold pressure. It calculates the pressure it wants, then adjusts the wastegate until it gets that pressure.
On the question of how to monitor the position of the fuel control rod. There are two variable reluctance sensors in the IP. The ECU sends an AC waveform to both and figures out the position by comparing the two responses. That is way out of the realm of amateur electronics. Also, note that the fuel control solenoid is very fast. Supposedly, the ECU can alter fuel volume on a cylinder by cylinder basis below 2000RPM. That is about 160 adjustments/second.
04-28-2015, 02:48 PM
#10
as i said dont understand much of electronics, i´ll try puting a AC current through the wires and measure what is coming out. one thing that makes me some confusion is why there´s only 3 wires, so as u say one receives 10hz ie and the the other 2 have a dif wave lenght, wich varies with the position? in this case what would be the frequency and intensity to use?
if its the case it will fit my purpose.
About the WG actuator and ECU , just now i realise u were talking about the w210, over 98 correct? well that has nothing to do with the w202 95, wich does not have boost sensor.
in that case that hardware(as long it produces VAC pulses) should be able to control the VNT device , but maybe u´ll need to write a new map for it.
FD,
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hy ,
as i said dont understand much of electronics, i´ll try puting a AC current through the wires and measure what is coming out. one thing that makes me some confusion is why there´s only 3 wires, so as u say one receives 10hz ie and the the other 2 have a dif wave lenght, wich varies with the position? in this case what would be the frequency and intensity to use?
if its the case it will fit my purpose.
About the WG actuator and ECU , just now i realise u were talking about the w210, over 98 correct? well that has nothing to do with the w202 95, wich does not have boost sensor.
in that case that hardware(as long it produces VAC pulses) should be able to control the VNT device , but maybe u´ll need to write a new map for it.
FD,
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04-28-2015, 05:11 PM
#11
(04-28-2015, 02:48 PM)barrote hy ,
as i said dont understand much of electronics, i´ll try puting a AC current through the wires and measure what is coming out. one thing that makes me some confusion is why there´s only 3 wires, so as u say one receives 10hz ie and the the other 2 have a dif wave lenght, wich varies with the position? in this case what would be the frequency and intensity to use?
if its the case it will fit my purpose.
About the WG actuator and ECU , just now i realise u were talking about the w210, over 98 correct? well that has nothing to do with the w202 95, wich does not have boost sensor.
in that case that hardware(as long it produces VAC pulses) should be able to control the VNT device , but maybe u´ll need to write a new map for it.
One line is just ground. On an engine with a working ECU, you'll need to watch the other two lines with an oscilloscope. If I remember correctly, this is a sine wave of ~3v at 10kHz. One line will have a stable voltage - that is the reference line. The other line changes voltage with the position of the fuel control rod.
The coils in the IP are only part of the circuit that makes the 10kHz signal, the rest is inside the ECU.
This post was last modified: 04-28-2015, 05:15 PM by AlanMcR.
(04-28-2015, 02:48 PM)barrote hy ,
as i said dont understand much of electronics, i´ll try puting a AC current through the wires and measure what is coming out. one thing that makes me some confusion is why there´s only 3 wires, so as u say one receives 10hz ie and the the other 2 have a dif wave lenght, wich varies with the position? in this case what would be the frequency and intensity to use?
if its the case it will fit my purpose.
About the WG actuator and ECU , just now i realise u were talking about the w210, over 98 correct? well that has nothing to do with the w202 95, wich does not have boost sensor.
in that case that hardware(as long it produces VAC pulses) should be able to control the VNT device , but maybe u´ll need to write a new map for it.
One line is just ground. On an engine with a working ECU, you'll need to watch the other two lines with an oscilloscope. If I remember correctly, this is a sine wave of ~3v at 10kHz. One line will have a stable voltage - that is the reference line. The other line changes voltage with the position of the fuel control rod.
The coils in the IP are only part of the circuit that makes the 10kHz signal, the rest is inside the ECU.
08-11-2015, 07:13 AM
#14
One problem I see with driving a VGT vane actuator with the original Mercedes control protocol is where is shuts wastegate 100% with maximum load request. you do not want VGT vanes closed at WOT because EGP would go sky high and slow you down / break engine through high EGT.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
Very interesting.
One problem I see with driving a VGT vane actuator with the original Mercedes control protocol is where is shuts wastegate 100% with maximum load request. you do not want VGT vanes closed at WOT because EGP would go sky high and slow you down / break engine through high EGT.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
08-11-2015, 07:14 AM
#15
(08-11-2015, 07:13 AM)Hario Very interesting.
One problem I see with driving a VGT vane actuator with the original Mercedes control protocol is where is shuts wastegate 100% with maximum load request. you do not want VGT vanes closed at WOT because EGP would go sky high and slow you down / break engine through high EGT.
Perhaps a manifold pressure referenced override on the vane actuation arm: An additional actuator which forced the vanes open as desired boost is achieved, sprung on the VGT actuator arm so they do not conflict.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
(08-11-2015, 07:13 AM)Hario Very interesting.
One problem I see with driving a VGT vane actuator with the original Mercedes control protocol is where is shuts wastegate 100% with maximum load request. you do not want VGT vanes closed at WOT because EGP would go sky high and slow you down / break engine through high EGT.
Perhaps a manifold pressure referenced override on the vane actuation arm: An additional actuator which forced the vanes open as desired boost is achieved, sprung on the VGT actuator arm so they do not conflict.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
08-11-2015, 07:59 AM
#17
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
It also opens up the wastegate when good boost is reached. It doesnt keep it shut the whole time.
87 300SDL OM606 swapped HE351VE 722.633 swapped, Crower cams, KM valvesprings
76 300TD custom lots of stuff
06 Mercedes CL65 AMG 619 WHP, http://TurboTims.com
08-11-2015, 01:19 PM
#19
(08-11-2015, 07:59 AM)Tu rboTim It also opens up the wastegate when good boost is reached. It doesnt keep it shut the whole time.
Exactly. This is a virtuous cycle. There won't be a lot of power until boost is achieved, so there also won't be a lot of backpressure. Once boost is achieved, the vanes begin to open, and the risk of excessive back pressure is reduced.
(08-11-2015, 07:59 AM)Tu rboTim It also opens up the wastegate when good boost is reached. It doesnt keep it shut the whole time.
Exactly. This is a virtuous cycle. There won't be a lot of power until boost is achieved, so there also won't be a lot of backpressure. Once boost is achieved, the vanes begin to open, and the risk of excessive back pressure is reduced.
08-12-2015, 06:35 AM
#21
(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
08-12-2015, 07:11 AM
#22
(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
Indeed, the VGT/VNT turbos need a vacuum source, I am tempted to upgrade my actuator on the stock turbo to a boost actuated one which would mean that it will always be ready to boost, the other option would be to use the OEM vacuum system for VGT/VNT turbos, its a shame that in the UK the Holset VNT turbos aren't the cheapest.
(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
Indeed, the VGT/VNT turbos need a vacuum source, I am tempted to upgrade my actuator on the stock turbo to a boost actuated one which would mean that it will always be ready to boost, the other option would be to use the OEM vacuum system for VGT/VNT turbos, its a shame that in the UK the Holset VNT turbos aren't the cheapest.
08-12-2015, 08:59 PM
#23
(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
08-13-2015, 06:33 AM
#24
(08-12-2015, 08:59 PM)AlanMcR(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
I have a spare stock KKK K14 turbo in the garage, although I have used to to try and create a hybrid turbo using a larger turbo off a Landcruiser, decided instead to just bolt on a GT35 - will still look into what mods could be done on the stock turbo though.
(08-12-2015, 08:59 PM)AlanMcR(08-12-2015, 06:35 AM)Hario(08-11-2015, 03:52 PM)m1tch Its probably just cheaper and more effective to change it to a boost actuated actuator rather than vacuum as then you can use the electronic boost controllers, although I am still looking at a VGT option.
I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
I have a spare stock KKK K14 turbo in the garage, although I have used to to try and create a hybrid turbo using a larger turbo off a Landcruiser, decided instead to just bolt on a GT35 - will still look into what mods could be done on the stock turbo though.
08-13-2015, 07:22 AM
#25
(08-13-2015, 06:33 AM)m1tch(08-12-2015, 08:59 PM)AlanMcR(08-12-2015, 06:35 AM)Hario I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
I have a spare stock KKK K14 turbo in the garage, although I have used to to try and create a hybrid turbo using a larger turbo off a Landcruiser, decided instead to just bolt on a GT35 - will still look into what mods could be done on the stock turbo though.
Die-grind wastegate hole & fit bigger flapper.
I have yet to install an EGP gauge but I think that is what it will tell me to do..
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
(08-13-2015, 06:33 AM)m1tch(08-12-2015, 08:59 PM)AlanMcR(08-12-2015, 06:35 AM)Hario I actually only pointed our about the vanes closed causing high EGP issue because if you use a normal boost actuator for vane control, at constant cruise speed boost will tail off and cause the actuator to close the vanes, boost would then build again. Anyway some american on PerformanceDiesel doccumented his trial it and it didn't work because of that problem.
A simple control system will have problems with the VNT. The factory ECU manages boost with a PID loop that predicts the mechanical response of the turbo to the control input. That PID is using parameters based on the KKK turbo. Realistically, the tiny KKK turbo may respond similarly to the VNT at light and moderate loads. At the top end things might get weird.
Question: Has anyone tried to increase the size of the KKK wastegate? That might make for a meaningful improvement in freeway mileage on my G. Half the exhaust is trying to fit itself through that tiny mouse hole.
I have a spare stock KKK K14 turbo in the garage, although I have used to to try and create a hybrid turbo using a larger turbo off a Landcruiser, decided instead to just bolt on a GT35 - will still look into what mods could be done on the stock turbo though.
Die-grind wastegate hole & fit bigger flapper.
I have yet to install an EGP gauge but I think that is what it will tell me to do..
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
08-14-2015, 07:59 AM
#27
(08-13-2015, 01:30 PM)baldur increasing the wastegate flow will only do one thing, it will enable you to run lower charge air pressure at high RPM. This may help fuel economy if you are seeing high boost levels when cruising.
I think the guy meant at WOT & high rpm the stock wastegate was causing EGP to rise due to being small and shit.
But good point, I get manifold pressure creeps up to about 5psi when I'm fast motorway cruising, perhaps it would help cruise mpg also.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
(08-13-2015, 01:30 PM)baldur increasing the wastegate flow will only do one thing, it will enable you to run lower charge air pressure at high RPM. This may help fuel economy if you are seeing high boost levels when cruising.
I think the guy meant at WOT & high rpm the stock wastegate was causing EGP to rise due to being small and shit.
But good point, I get manifold pressure creeps up to about 5psi when I'm fast motorway cruising, perhaps it would help cruise mpg also.
Installed:
OM606/722.6, big IC, W220 brakes.
Planned:
DIY manifold, compound, 722.6 controller, built IP.
[i]Less rust.. [/i]
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