4-port Boost Control Solenoid
04-22-14, 01:13 PM
#28
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Not sure that's how open loop works.
Put 100% DC up to your desired boost. At your desired boost level use a different DC to control boost.
100% dc from zero to 15 psi
at 16 psi put 35% dc. You may over shoot 15 but settle back down. If over boost a lot increase (lower DC number) the DC.
closed loop, you put a start DC at a set boost.
Anther plus to going with a lighter spring is the valve moves further off the seat then with a heavier spring. I had a 12 psi spring in my gate and the valve movement was limited. Misplace my 5 psi spring so I cut two coils off the 12 psi spring and not I get move movement from the valve off the seat. Now my gate flows.
Found my 5 psi spring and measured it collapsed height and that would have work the same.
Put 100% DC up to your desired boost. At your desired boost level use a different DC to control boost.
100% dc from zero to 15 psi
at 16 psi put 35% dc. You may over shoot 15 but settle back down. If over boost a lot increase (lower DC number) the DC.
closed loop, you put a start DC at a set boost.
Anther plus to going with a lighter spring is the valve moves further off the seat then with a heavier spring. I had a 12 psi spring in my gate and the valve movement was limited. Misplace my 5 psi spring so I cut two coils off the 12 psi spring and not I get move movement from the valve off the seat. Now my gate flows.
Found my 5 psi spring and measured it collapsed height and that would have work the same.
04-22-14, 04:05 PM
#29
Haltech has a step by step setup process in their help section, it shouldn't take more than 3-4 passes or a few pulls to get one boost level dialed in. If you are doing boost by gear or varying boost it will take a little longer to get the start duty cycles dialed in.
OP, those DC do seem a bit high to me as well. 25% got me about 20psi, 45% was over 44psi
OP, those DC do seem a bit high to me as well. 25% got me about 20psi, 45% was over 44psi
I was under the impression that everytime I want to run a different boost pressure, I had to set everything up under the closed loop boost settings; and it wasn't a matter of saying a specific amount of pressure.
04-22-14, 04:46 PM
#30
So, lets say I have closed loop boost control set to 15 psi, working properly, and now I want to run 20psi. Where do I set the boost pressure to 20psi?
Are you talking about the haltech section on this forum? I've read/used Crispeed, Cludwig, and Arghx guides for setting up open/closed loop; and failed at finding any info on the haltech site (other than the open/closed loop video) If its on the haltech site, could you post a link?
I was under the impression that everytime I want to run a different boost pressure, I had to set everything up under the closed loop boost settings; and it wasn't a matter of saying a specific amount of pressure.
Are you talking about the haltech section on this forum? I've read/used Crispeed, Cludwig, and Arghx guides for setting up open/closed loop; and failed at finding any info on the haltech site (other than the open/closed loop video) If its on the haltech site, could you post a link?
I was under the impression that everytime I want to run a different boost pressure, I had to set everything up under the closed loop boost settings; and it wasn't a matter of saying a specific amount of pressure.
It's in the help section of the ecm manager software, i found it by accident. If you want to run different boost levels (once all the start duty cycles are enter for different boost levels) all you have to do is change the target boost and that's it. You can also use the trim pot or boost by gear to do different boost levels.
"Description
The wastegate of a turbo is operated when the manifold pressure acting on the diaphragm within the wastegate actuator overcomes the return spring allowing exhaust gas to bypass the turbine. With electronic boost control, the object is to use a solenoid to bleed off the manifold pressure signal seen by the waste gate unit so that it can see only a fraction of the manifold pressure. The solenoid operates at constant frequency and the duty cycle is altered to control the drop in pressure signal through the device.
WARNING:
Adjusting the boost levels for a turbo engine can alter its fuel requirements drastically. If the fuel requirements are not tuned simultaneously with changes in boost characteristics, engine damage could result. To avoid engine damage, watch your Air/Fuel ratios very carefully when increasing boost. Also check that your fuel system will be capable of delivering the required fuel for the increase in boost.
Open Loop Tuning
The Open Loop table allows boost to be increased over the standard boost that the turbo and wastegate combination provides. The turbo wastegate solenoid will only activate when it sees positive manifold pressure.
To setup the Open Loop table, it will be necessary to iterate through several trial and error runs to ensure safe boost conditions. Use the following steps as a guide to setting up your Open Loop table:
Always start with small duty cycle settings and increase until the desired boost level is reached. Start with a flat map (same duty at all loads and speeds) at low duty settings and drive the car noting any increase in boost level.
Watch you’re A/F ratios very carefully when increasing boost for the first time as this part of the map will not have been tested if this engine has not been mapped at this boost level.
You can setup a flat map easily by selecting all the necessary cells, then typing in the duty value. Make sure you run the engine at the engine load and RPM at which maximum boost is typically reached. This is usually in the mid range of the RPM range of the engine.
Adjust the duty of all the cells of the table if necessary, increasing duty to increase boost, decreasing duty to decrease boost and apply load to the engine to check the resulting boost level. Again, make sure that your fuel maps are adjusted to ensure safe A/F ratios at every step. Repeat until the desired maximum boost is reached.
Now that you have set the Open Loop table to achieve the maximum desired boost at the peak operating range, you can increase the duty cycle at all engine speeds and loads at which the boost pressure is below the desired maximum boost. This will help the engine reach its desired boost pressure quicker. This will alter the fuel requirements at these engine loads and speeds so watch you A/F ratios carefully and adjust your fuel maps to compensate if required.
Similarly, if a lower target boost is required at certain operating ranges of the engine, such as high RPM where injectors may be near 100% duty, it may be necessary to lower the duty at those points to reduce boost levels.
Closed Loop Tuning
Basic Closed Loop Setup Procedure
The Basic Setup Procedure is a guide on how to get some basic parameters in place to allow the closed loop boost controller to operate.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Choose Closed Loop for the Control Type.
Set the frequency of the Turbo Waste Gate solenoid in the ‘Frequency’ setting. The Haltech waste gate solenoid runs at a frequency of 20 – 30 Hz.
Disable the controller by setting Proportional – 0%, Integral – 0% and Derivative – 0%.
Set the ‘Control Point Before Target’ to the default value of 20 kPa (3 PSI).
Set the ‘Delay till Boost Control’ to the default value of 0.5 sec.
Set the ‘Target Boost’ table at the boost level that you want to run across the whole RPM range.
Set the ‘Start Duty’ to a duty cycle that should get you close to your boost target. Start at a small duty, then slowly increase to avoid overboosting.
Put the engine under sufficient load (i.e. on a dyno) to get it to reach the target boost level. Watch to make sure it does not over boost. View the duty cycle of the wastegate, by displaying the Duty channel of the output that the boost controller is setup on. E.g. If boost control is setup on DPO1, then view Digital Pulse Output 1 Duty. If the boost level exceeds the target boost level reduce the ‘Start Duty’, if the boost is far away from the target boost level, then increase ‘Start Duty’. The final value should allow boost to come close to, but just below the target boost level. If Start Duty is set too high, the controller will spike when coming on boost. If it is set too low, then it will start low and slowly rise to the target.
Once you are satisfied with your Start Duty setting, turn on the controller by restoring the Proportional, Integral and Derivative to the following settings:
Proportional - 50%
Integral - 0%
Derivative - 0%
Adjust Proportional until your boost starts to oscillate. Once you find this value, set the Proportional to about half this value. While tuning this value, your boost may still not hit the target boost exactly. This is normal at this stage.
Once you are satisfied with your Proportional setting, start increasing the Integral value until the target boost is close enough to the target level that you wish to run.
Once Proportional and Integral are set, check to see if you have any overshoot when hitting the target. If you have some overshoot, then increase Derivative until that overshoot is minimised. Use caution when increasing Derivative as this setting is very sensitive and should be increased very slowly otherwise, unstable boost control may result.
Setup of the Start Duty Map
If the Target Boost is varying over RPM, or by either a boost trim or gear boost correction then it is a good idea to setup the ‘Start Duty’ table. The Start Duty is closedly related to the target boost, so a different Start Duty for each Target Boost will allow better control over boost levels.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Firstly leave the ‘Use Start Duty Table’ un-ticked. Set the entire ‘Target Boost’ table to the lowest desired boost level that you wish to run.
Use the above procedure for setting up Basic Closed Loop Setup Procedure and stop at step 8. Record the ‘Start Duty Cycle’ and the corresponding Target Boost. Increment the ‘Target Boost’ by about 20 kPa (3 PSI) and repeat steps 6 to 8 and record the ‘Start Duty Cycle’ and the corresponding Target Boost again. Repeat this procedure until you reach the max boost that the engine is going to run. You should have a table of Start Duty values against Target Boost levels every 20kPa or 3psi.
Fill out the ‘Start Duty’ table with the data recorded. For the Target Boost Level columns above the highest target that you wish to run, use the highest value Start Duty that you have recorded. For the Target Boost Levels below the lowest target that you wish to run, taper off the Start Duty values below this column until you reach zero duty when at the wastegate spring pressure column.
In the example above, the maximum boost was 140kPa, with the Start Duty values levelled off above this Target Boost. 100kPa is the minimum Target Boost and the Start Duty values below this are tapered off down to around 50kPa.
Tick the ‘Use Start Duty Table’ in the closed loop boost control setup.
(Optional) To fine-tune the ‘Start Duty’ table, setup a closed boost control trim under the analog input function page and load up the engine at different boost levels to make sure that the boost control runs smoothly"
04-22-14, 05:01 PM
#31
https://www.rx7club.com/haltech-foru...s-work-950758/
specifically posts 7 and 8 .
Basically, what I recommend is setting the entire curve to the same value and ramp it up. Then adjust by rpm to reduce boost tapering off. Then tweak by load for desired throttle response. Then make your gear or throttle based corrections, with air temp correction coming towards the end of the process.
That's for open loop control. If you are using closed loop, dial in proportional gain after setting up all that. Do the integral gain last, and derivative gain is usually not used. The idea is to run it "dumb" like an MBC first, so it's simple, and then tweak it in a logical way. There's more than one to set the closed loop parameters, and every system works differently. For example, on some systems your gain is set based on error rather than a single value. So you can adjust how strong the gains are based on the difference between target and actual boost.
Keep in mind that OP is using an older Motec. I've helped him with it before, but I don't think I have the software working on this computer.
04-22-14, 06:53 PM
#33
Yes, arghx has helped me in the past (thank you very much), and I'm also using the MoTeC webinars. For those that aren't already expert at it, I think they're useful.
Open Loop:
Closed Loop:
I'll finish setting up my open loop table, then start working on closed loop.
Open Loop:
Closed Loop:
I'll finish setting up my open loop table, then start working on closed loop.
04-22-14, 07:05 PM
#34
3lb springs may be a little low, i would recommend a spring that's maybe 2lb less than the lowest boost you plan on running. You may also try pulling pressure straight from the compressor housing. I don't know what ECM you are running but it could also be possible to play with the control start points and the start duty cycles. IE you can have it where it starts the boost control 3psi before the target and enter a start duty cycle appropriate for a lower than target boost. Doing that would start the control sooner and bring it in more gradually. hope that makes sense.
The lowest boost I plan on running is only 3psi. Since my system won't go any lower, I guess I'll have to settle for 5 psi. I want the low boost level so I can get better throttle modulation -- both when I'm cornering on a road course and when I'm launching the car from a standstill.
I'll see if I can get it to act the way I want with the current springs. If not, maybe I need stiffer springs or a larger dia exhaust.
And yes, I do understand your logic regarding an artificially low DC set point so the system will gradually build to the target boost.
04-23-14, 06:00 AM
#36
It's in the help section of the ecm manager software, i found it by accident. If you want to run different boost levels (once all the start duty cycles are enter for different boost levels) all you have to do is change the target boost and that's it. You can also use the trim pot or boost by gear to do different boost levels.
"Description
The wastegate of a turbo is operated when the manifold pressure acting on the diaphragm within the wastegate actuator overcomes the return spring allowing exhaust gas to bypass the turbine. With electronic boost control, the object is to use a solenoid to bleed off the manifold pressure signal seen by the waste gate unit so that it can see only a fraction of the manifold pressure. The solenoid operates at constant frequency and the duty cycle is altered to control the drop in pressure signal through the device.
WARNING:
Adjusting the boost levels for a turbo engine can alter its fuel requirements drastically. If the fuel requirements are not tuned simultaneously with changes in boost characteristics, engine damage could result. To avoid engine damage, watch your Air/Fuel ratios very carefully when increasing boost. Also check that your fuel system will be capable of delivering the required fuel for the increase in boost.
Open Loop Tuning
The Open Loop table allows boost to be increased over the standard boost that the turbo and wastegate combination provides. The turbo wastegate solenoid will only activate when it sees positive manifold pressure.
To setup the Open Loop table, it will be necessary to iterate through several trial and error runs to ensure safe boost conditions. Use the following steps as a guide to setting up your Open Loop table:
Always start with small duty cycle settings and increase until the desired boost level is reached. Start with a flat map (same duty at all loads and speeds) at low duty settings and drive the car noting any increase in boost level.
Watch you’re A/F ratios very carefully when increasing boost for the first time as this part of the map will not have been tested if this engine has not been mapped at this boost level.
You can setup a flat map easily by selecting all the necessary cells, then typing in the duty value. Make sure you run the engine at the engine load and RPM at which maximum boost is typically reached. This is usually in the mid range of the RPM range of the engine.
Adjust the duty of all the cells of the table if necessary, increasing duty to increase boost, decreasing duty to decrease boost and apply load to the engine to check the resulting boost level. Again, make sure that your fuel maps are adjusted to ensure safe A/F ratios at every step. Repeat until the desired maximum boost is reached.
Now that you have set the Open Loop table to achieve the maximum desired boost at the peak operating range, you can increase the duty cycle at all engine speeds and loads at which the boost pressure is below the desired maximum boost. This will help the engine reach its desired boost pressure quicker. This will alter the fuel requirements at these engine loads and speeds so watch you A/F ratios carefully and adjust your fuel maps to compensate if required.
Similarly, if a lower target boost is required at certain operating ranges of the engine, such as high RPM where injectors may be near 100% duty, it may be necessary to lower the duty at those points to reduce boost levels.
Closed Loop Tuning
Basic Closed Loop Setup Procedure
The Basic Setup Procedure is a guide on how to get some basic parameters in place to allow the closed loop boost controller to operate.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Choose Closed Loop for the Control Type.
Set the frequency of the Turbo Waste Gate solenoid in the ‘Frequency’ setting. The Haltech waste gate solenoid runs at a frequency of 20 – 30 Hz.
Disable the controller by setting Proportional – 0%, Integral – 0% and Derivative – 0%.
Set the ‘Control Point Before Target’ to the default value of 20 kPa (3 PSI).
Set the ‘Delay till Boost Control’ to the default value of 0.5 sec.
Set the ‘Target Boost’ table at the boost level that you want to run across the whole RPM range.
Set the ‘Start Duty’ to a duty cycle that should get you close to your boost target. Start at a small duty, then slowly increase to avoid overboosting.
Put the engine under sufficient load (i.e. on a dyno) to get it to reach the target boost level. Watch to make sure it does not over boost. View the duty cycle of the wastegate, by displaying the Duty channel of the output that the boost controller is setup on. E.g. If boost control is setup on DPO1, then view Digital Pulse Output 1 Duty. If the boost level exceeds the target boost level reduce the ‘Start Duty’, if the boost is far away from the target boost level, then increase ‘Start Duty’. The final value should allow boost to come close to, but just below the target boost level. If Start Duty is set too high, the controller will spike when coming on boost. If it is set too low, then it will start low and slowly rise to the target.
Once you are satisfied with your Start Duty setting, turn on the controller by restoring the Proportional, Integral and Derivative to the following settings:
Proportional - 50%
Integral - 0%
Derivative - 0%
Adjust Proportional until your boost starts to oscillate. Once you find this value, set the Proportional to about half this value. While tuning this value, your boost may still not hit the target boost exactly. This is normal at this stage.
Once you are satisfied with your Proportional setting, start increasing the Integral value until the target boost is close enough to the target level that you wish to run.
Once Proportional and Integral are set, check to see if you have any overshoot when hitting the target. If you have some overshoot, then increase Derivative until that overshoot is minimised. Use caution when increasing Derivative as this setting is very sensitive and should be increased very slowly otherwise, unstable boost control may result.
Setup of the Start Duty Map
If the Target Boost is varying over RPM, or by either a boost trim or gear boost correction then it is a good idea to setup the ‘Start Duty’ table. The Start Duty is closedly related to the target boost, so a different Start Duty for each Target Boost will allow better control over boost levels.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Firstly leave the ‘Use Start Duty Table’ un-ticked. Set the entire ‘Target Boost’ table to the lowest desired boost level that you wish to run.
Use the above procedure for setting up Basic Closed Loop Setup Procedure and stop at step 8. Record the ‘Start Duty Cycle’ and the corresponding Target Boost. Increment the ‘Target Boost’ by about 20 kPa (3 PSI) and repeat steps 6 to 8 and record the ‘Start Duty Cycle’ and the corresponding Target Boost again. Repeat this procedure until you reach the max boost that the engine is going to run. You should have a table of Start Duty values against Target Boost levels every 20kPa or 3psi.
Fill out the ‘Start Duty’ table with the data recorded. For the Target Boost Level columns above the highest target that you wish to run, use the highest value Start Duty that you have recorded. For the Target Boost Levels below the lowest target that you wish to run, taper off the Start Duty values below this column until you reach zero duty when at the wastegate spring pressure column.
In the example above, the maximum boost was 140kPa, with the Start Duty values levelled off above this Target Boost. 100kPa is the minimum Target Boost and the Start Duty values below this are tapered off down to around 50kPa.
Tick the ‘Use Start Duty Table’ in the closed loop boost control setup.
(Optional) To fine-tune the ‘Start Duty’ table, setup a closed boost control trim under the analog input function page and load up the engine at different boost levels to make sure that the boost control runs smoothly"
The wastegate of a turbo is operated when the manifold pressure acting on the diaphragm within the wastegate actuator overcomes the return spring allowing exhaust gas to bypass the turbine. With electronic boost control, the object is to use a solenoid to bleed off the manifold pressure signal seen by the waste gate unit so that it can see only a fraction of the manifold pressure. The solenoid operates at constant frequency and the duty cycle is altered to control the drop in pressure signal through the device.
WARNING:
Adjusting the boost levels for a turbo engine can alter its fuel requirements drastically. If the fuel requirements are not tuned simultaneously with changes in boost characteristics, engine damage could result. To avoid engine damage, watch your Air/Fuel ratios very carefully when increasing boost. Also check that your fuel system will be capable of delivering the required fuel for the increase in boost.
Open Loop Tuning
The Open Loop table allows boost to be increased over the standard boost that the turbo and wastegate combination provides. The turbo wastegate solenoid will only activate when it sees positive manifold pressure.
To setup the Open Loop table, it will be necessary to iterate through several trial and error runs to ensure safe boost conditions. Use the following steps as a guide to setting up your Open Loop table:
Always start with small duty cycle settings and increase until the desired boost level is reached. Start with a flat map (same duty at all loads and speeds) at low duty settings and drive the car noting any increase in boost level.
Watch you’re A/F ratios very carefully when increasing boost for the first time as this part of the map will not have been tested if this engine has not been mapped at this boost level.
You can setup a flat map easily by selecting all the necessary cells, then typing in the duty value. Make sure you run the engine at the engine load and RPM at which maximum boost is typically reached. This is usually in the mid range of the RPM range of the engine.
Adjust the duty of all the cells of the table if necessary, increasing duty to increase boost, decreasing duty to decrease boost and apply load to the engine to check the resulting boost level. Again, make sure that your fuel maps are adjusted to ensure safe A/F ratios at every step. Repeat until the desired maximum boost is reached.
Now that you have set the Open Loop table to achieve the maximum desired boost at the peak operating range, you can increase the duty cycle at all engine speeds and loads at which the boost pressure is below the desired maximum boost. This will help the engine reach its desired boost pressure quicker. This will alter the fuel requirements at these engine loads and speeds so watch you A/F ratios carefully and adjust your fuel maps to compensate if required.
Similarly, if a lower target boost is required at certain operating ranges of the engine, such as high RPM where injectors may be near 100% duty, it may be necessary to lower the duty at those points to reduce boost levels.
Closed Loop Tuning
Basic Closed Loop Setup Procedure
The Basic Setup Procedure is a guide on how to get some basic parameters in place to allow the closed loop boost controller to operate.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Choose Closed Loop for the Control Type.
Set the frequency of the Turbo Waste Gate solenoid in the ‘Frequency’ setting. The Haltech waste gate solenoid runs at a frequency of 20 – 30 Hz.
Disable the controller by setting Proportional – 0%, Integral – 0% and Derivative – 0%.
Set the ‘Control Point Before Target’ to the default value of 20 kPa (3 PSI).
Set the ‘Delay till Boost Control’ to the default value of 0.5 sec.
Set the ‘Target Boost’ table at the boost level that you want to run across the whole RPM range.
Set the ‘Start Duty’ to a duty cycle that should get you close to your boost target. Start at a small duty, then slowly increase to avoid overboosting.
Put the engine under sufficient load (i.e. on a dyno) to get it to reach the target boost level. Watch to make sure it does not over boost. View the duty cycle of the wastegate, by displaying the Duty channel of the output that the boost controller is setup on. E.g. If boost control is setup on DPO1, then view Digital Pulse Output 1 Duty. If the boost level exceeds the target boost level reduce the ‘Start Duty’, if the boost is far away from the target boost level, then increase ‘Start Duty’. The final value should allow boost to come close to, but just below the target boost level. If Start Duty is set too high, the controller will spike when coming on boost. If it is set too low, then it will start low and slowly rise to the target.
Once you are satisfied with your Start Duty setting, turn on the controller by restoring the Proportional, Integral and Derivative to the following settings:
Proportional - 50%
Integral - 0%
Derivative - 0%
Adjust Proportional until your boost starts to oscillate. Once you find this value, set the Proportional to about half this value. While tuning this value, your boost may still not hit the target boost exactly. This is normal at this stage.
Once you are satisfied with your Proportional setting, start increasing the Integral value until the target boost is close enough to the target level that you wish to run.
Once Proportional and Integral are set, check to see if you have any overshoot when hitting the target. If you have some overshoot, then increase Derivative until that overshoot is minimised. Use caution when increasing Derivative as this setting is very sensitive and should be increased very slowly otherwise, unstable boost control may result.
Setup of the Start Duty Map
If the Target Boost is varying over RPM, or by either a boost trim or gear boost correction then it is a good idea to setup the ‘Start Duty’ table. The Start Duty is closedly related to the target boost, so a different Start Duty for each Target Boost will allow better control over boost levels.
It is assumed that all the target boost levels are above the wastegate spring pressure. The electronic boost controller cannot control boost below the wastegate spring pressure.
Firstly leave the ‘Use Start Duty Table’ un-ticked. Set the entire ‘Target Boost’ table to the lowest desired boost level that you wish to run.
Use the above procedure for setting up Basic Closed Loop Setup Procedure and stop at step 8. Record the ‘Start Duty Cycle’ and the corresponding Target Boost. Increment the ‘Target Boost’ by about 20 kPa (3 PSI) and repeat steps 6 to 8 and record the ‘Start Duty Cycle’ and the corresponding Target Boost again. Repeat this procedure until you reach the max boost that the engine is going to run. You should have a table of Start Duty values against Target Boost levels every 20kPa or 3psi.
Fill out the ‘Start Duty’ table with the data recorded. For the Target Boost Level columns above the highest target that you wish to run, use the highest value Start Duty that you have recorded. For the Target Boost Levels below the lowest target that you wish to run, taper off the Start Duty values below this column until you reach zero duty when at the wastegate spring pressure column.
In the example above, the maximum boost was 140kPa, with the Start Duty values levelled off above this Target Boost. 100kPa is the minimum Target Boost and the Start Duty values below this are tapered off down to around 50kPa.
Tick the ‘Use Start Duty Table’ in the closed loop boost control setup.
(Optional) To fine-tune the ‘Start Duty’ table, setup a closed boost control trim under the analog input function page and load up the engine at different boost levels to make sure that the boost control runs smoothly"
Don't mean to highjack this thread, but that method causes boost spike and oscillation in my setup. I am guessing is because I have a fairly fast boost response/spool, and I am not intending to run much more boost than the wastegate spring?
04-23-14, 07:45 PM
#37
The gate has to crack open before intended boost level unless you are willing to tolerate noticeable overshoot. There is a basic time lag in the system for the solenoid, diaphragm in the gate, and poppet valve in the gate to operate. Now, you can still tweak the wastegate spring, boost control plumbing and duty cycle etc so that you can open the gate at the last possible instant.
04-26-14, 08:43 AM
#38
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[QUOTE=KNONFS;11723681
Don't mean to highjack this thread, but that method causes boost spike and oscillation in my setup. I am guessing is because I have a fairly fast boost response/spool, and I am not intending to run much more boost than the wastegate spring?[/QUOTE]
What's wrong with a little more boost before and after peak boost rpms?
Don't mean to highjack this thread, but that method causes boost spike and oscillation in my setup. I am guessing is because I have a fairly fast boost response/spool, and I am not intending to run much more boost than the wastegate spring?[/QUOTE]
What's wrong with a little more boost before and after peak boost rpms?
04-26-14, 10:44 AM
#39
I've been setting up my open loop boost table. It's based on RPM vs throttle position, and I started at the lower boost levels and worked upward. It's been going well, but with the cold temps here (in the 40's), I'm losing traction in 3rd gear at anything over 13 PSI. It's wait until it warms up or put sand bags in the back.
At approx. 10 PSI, the system requires a significant increase in duty cycle to maintain it as the RPMs rise.
At approx. 10 PSI, the system requires a significant increase in duty cycle to maintain it as the RPMs rise.
05-18-14, 09:06 PM
#42
It's been cold and rainy here in Michigan, plus with business travel, I haven't been able to tune for over two weeks, but this weekend things improved enough for me to make headway.
I set up my open loop duty cycle table and found that the max boost I could maintain across the rev range with my 3 PSI springs was 16 PSI. I was able to hit 20 PSI or more at 4K RPM, but it would steadily decline at the higher revs, and even at max effective solenoid duty cycle (which seems to be about 90%), it wasn't enough to maintain the boost all the way to 8K RPM.
I decided that it felt pretty fast at 16 PSI, so I set up my closed loop table to gradually increase boost with throttle position from 5 PSI base boost (0% thru 50% throttle position) to 16 PSI at 100% throttle position.
The result is steady 16 PSI across the rev range at WOT. But what's even better is that now I can modulate the power when I launch the car. Beforehand, I had a 9 PSI spring with a 3-port solenoid, and as soon as I got past 3500 RPM, the rear tires would light up in 1st or 2nd gear. If I backed off the throttle enough to stop the wheels from spinning, I would lose all boost. It was like a light switch.
Now, I can give it part throttle, and I get part boost. It feels more like I'm driving a big NA engine as far as the modulation is concerned -- but it's like a big NA engine that continues to make power past 8K RPM. This is very nice. Wish I'd done it years ago.
I set up my open loop duty cycle table and found that the max boost I could maintain across the rev range with my 3 PSI springs was 16 PSI. I was able to hit 20 PSI or more at 4K RPM, but it would steadily decline at the higher revs, and even at max effective solenoid duty cycle (which seems to be about 90%), it wasn't enough to maintain the boost all the way to 8K RPM.
I decided that it felt pretty fast at 16 PSI, so I set up my closed loop table to gradually increase boost with throttle position from 5 PSI base boost (0% thru 50% throttle position) to 16 PSI at 100% throttle position.
The result is steady 16 PSI across the rev range at WOT. But what's even better is that now I can modulate the power when I launch the car. Beforehand, I had a 9 PSI spring with a 3-port solenoid, and as soon as I got past 3500 RPM, the rear tires would light up in 1st or 2nd gear. If I backed off the throttle enough to stop the wheels from spinning, I would lose all boost. It was like a light switch.
Now, I can give it part throttle, and I get part boost. It feels more like I'm driving a big NA engine as far as the modulation is concerned -- but it's like a big NA engine that continues to make power past 8K RPM. This is very nice. Wish I'd done it years ago.
05-27-14, 08:13 PM
#43
The issue is this: When I launch the car with my current 9psi spring, I light up the rear tires uncontrollably in 1st and 2nd gear. If I back off on the throttle, I don't get any noticeable reduction in power unless I back off so far I don't have any boost.
I want to setup a boost table based on throttle position and RPM that will give me more boost as I feed in more throttle. To make this useful, I need to be able to run less than 9psi at small throttle openings and still be able to run upwards of 15psi at WOT?
I want to setup a boost table based on throttle position and RPM that will give me more boost as I feed in more throttle. To make this useful, I need to be able to run less than 9psi at small throttle openings and still be able to run upwards of 15psi at WOT?
In my late / dead 1st gen turbo I was using a 3.636 2-way LSD final drive with 205 50 R15 Yokohama A050 Circuit radials and I could still spin all through 1st gear at half throttle even using tyre pressures like 18psi on prepared drag strip.
With my setup I came to the conclusion that the solution was a 3.9 or 4.1 diff combined with an OSGiken close ratio transmission because the real problem is 1st gear's ratio and the 1-2nd gear step.
05-27-14, 09:08 PM
#44
What rear end ratio are you using?
In my late / dead 1st gen turbo I was using a 3.636 2-way LSD final drive with 205 50 R15 Yokohama A050 Circuit radials and I could still spin all through 1st gear at half throttle even using tyre pressures like 18psi on prepared drag strip.
With my setup I came to the conclusion that the solution was a 3.9 or 4.1 diff combined with an OSGiken close ratio transmission because the real problem is 1st gear's ratio and the 1-2nd gear step.
In my late / dead 1st gen turbo I was using a 3.636 2-way LSD final drive with 205 50 R15 Yokohama A050 Circuit radials and I could still spin all through 1st gear at half throttle even using tyre pressures like 18psi on prepared drag strip.
With my setup I came to the conclusion that the solution was a 3.9 or 4.1 diff combined with an OSGiken close ratio transmission because the real problem is 1st gear's ratio and the 1-2nd gear step.
I'm running a 4.10 Torsen rear end with an early FC trans . . . but things have improved dramatically:
1) I dropped the pressure in my Kumho V700s (225/50-15) to 20 PSI (was 28)
2) I now only get about 5psi of boost at 1/2 throttle (vs. 12 or more)
3) I changed the angle of the trailing arms on my 3-link to get better anti-squat
4) It's up to 80 degrees ambient here now
I've been on many road courses, and only one drag strip, so I'm not an expert at launching a car, but it's much better than it was. I plan to go to a strip this summer and see what she'll do.
Also, I don't think I want a close ratio trans because I like to make high speed runs, and my current 5th gear ratio is just about perfect.
05-27-14, 09:21 PM
#45
FB RIP
I'm running a 4.10 Torsen rear end with an early FC trans . . . but things have improved dramatically:
1) I dropped the pressure in my Kumho V700s (225/50-15) to 20 PSI (was 28)
2) I now only get about 5psi of boost at 1/2 throttle (vs. 12 or more)
3) I changed the angle of the trailing arms on my 3-link to get better anti-squat
4) It's up to 80 degrees ambient here now
I've been on many road courses, and only one drag strip, so I'm not an expert at launching a car, but it's much better than it was. I plan to go to a strip this summer and see what she'll do.
Also, I don't think I want a close ratio trans because I like to make high speed runs, and my current 5th gear ratio is just about perfect.
I'm running a 4.10 Torsen rear end with an early FC trans . . . but things have improved dramatically:
1) I dropped the pressure in my Kumho V700s (225/50-15) to 20 PSI (was 28)
2) I now only get about 5psi of boost at 1/2 throttle (vs. 12 or more)
3) I changed the angle of the trailing arms on my 3-link to get better anti-squat
4) It's up to 80 degrees ambient here now
I've been on many road courses, and only one drag strip, so I'm not an expert at launching a car, but it's much better than it was. I plan to go to a strip this summer and see what she'll do.
Also, I don't think I want a close ratio trans because I like to make high speed runs, and my current 5th gear ratio is just about perfect.
You can apparently put the 3rd gen 0.719 5th gear in the FC3S transmission. My box is a jap import so it had the 0.806 5th gear.
I was using a 89-91 FC3S transmission (the only difference is the V shaped mount) and the harmonic balancer on the output shaft of the late ones.
12-23-15, 01:41 PM
#46
FB RIP
I'm running a 4.10 Torsen rear end with an early FC trans . . . but things have improved dramatically:
1) I dropped the pressure in my Kumho V700s (225/50-15) to 20 PSI (was 28)
2) I now only get about 5psi of boost at 1/2 throttle (vs. 12 or more)
3) I changed the angle of the trailing arms on my 3-link to get better anti-squat
4) It's up to 80 degrees ambient here now
I've been on many road courses, and only one drag strip, so I'm not an expert at launching a car, but it's much better than it was. I plan to go to a strip this summer and see what she'll do.
Also, I don't think I want a close ratio trans because I like to make high speed runs, and my current 5th gear ratio is just about perfect.
I'm running a 4.10 Torsen rear end with an early FC trans . . . but things have improved dramatically:
1) I dropped the pressure in my Kumho V700s (225/50-15) to 20 PSI (was 28)
2) I now only get about 5psi of boost at 1/2 throttle (vs. 12 or more)
3) I changed the angle of the trailing arms on my 3-link to get better anti-squat
4) It's up to 80 degrees ambient here now
I've been on many road courses, and only one drag strip, so I'm not an expert at launching a car, but it's much better than it was. I plan to go to a strip this summer and see what she'll do.
Also, I don't think I want a close ratio trans because I like to make high speed runs, and my current 5th gear ratio is just about perfect.
I have the same problem with lack of traction at part throttle and have been thinking about mapping boost vs throttle position so I'm interested how this worked out for you.
12-29-15, 05:57 AM
#48
The 4-port solenoids seem to have a narrower range of duty cycle where they are effective. A MAC 3-port works well in the 20-80% range. A MAC 4-port more like 30-80%. The ultimate in control, IMO, is using two 3-port solenoids, one for each side of the gate, and using an ECU that is capable of independent control of each in closed loop. Not many ECUs are doing that though.
12-29-15, 11:04 AM
#49
It's been a while since I messed around with my car (weather and other priorities), but my drag strip experience was very educational. Even with the new 4-port, I still had traction problems. My 60-foot times were terrible. As an example of just how bad, my friend's 2012 C6 (only mod is a catback exhaust, on street tires) jumped out to a 3 car length lead. I was eventually able to run him down and win by two car lengths.
I'm going to mess around with traction control in the spring. There's just too much of a rubber band effect with throttle inputs to modulate it effectively.
I'm going to mess around with traction control in the spring. There's just too much of a rubber band effect with throttle inputs to modulate it effectively.
12-29-15, 03:02 PM
#50
Senior Member
The 4-port solenoids seem to have a narrower range of duty cycle where they are effective. A MAC 3-port works well in the 20-80% range. A MAC 4-port more like 30-80%. The ultimate in control, IMO, is using two 3-port solenoids, one for each side of the gate, and using an ECU that is capable of independent control of each in closed loop. Not many ECUs are doing that though.
I say this because if I had known in advance, I probably would have gone with a 4 port. We are running a PT6266 with max boost set to 20psi. This makes it so we have to run a 12 psi spring, and even with the boost solenoid powered down, that 12psi is a hand full. It would be great to be able to run the spring at 9psi, or even lower. That way if the wife, or valet, or anyone else ends up in the driver seat, it wouldn't be such a scary experience.