Boost Control Setup

[andreas27s]

I need help with the setting of the table in the boost control tab. I am running the MAC valve as specified for applications with single wastegate and the engine is a 3sgte in an MR2. First I want to make sure that I have the solenoid hooked up properly. I have the top port of the wastegate going into port #2 on the solenoid, with port #1 going to the left side of the t-fitting, bottom port of the t-fitting going to the bottom of the wastegate, and the right side of the t-fitting going to the intake manifold.The #3 port on the solenoid is the vent. If this is not correctly, can someone tell me how else to hook it up?

I am trying to set up the open loop boost control, and that is what I will be dealing with exclusively at this point. I am trying to set the ems to 17psi as that is what the car was tuned to when I got it professionally tuned with all of the same components on the car right now. The solenoid was not in place yet and I had a manual boost controller at the time. I bought a solenoid after and hooked it up using the stock boost control wires as specified by my mechanic since they are still active, but now just need the figures which will set the boost to my desired pressure.

Help as soon as possible would be greatly appreciated. Thank you.

[Simon]

Hi

Plumbing wise that will be ok assuming the T piece is big enough. It is better to run two lines back to the manifold if possible.

In open loop mode just remember the bigger the duty cycle the more boost.

[andreas27s]

Yes, the t-piece is definitely big enough. I believe it is a 1/4" one because the small one I had on the Manual Boost controller split, so I got a brass one to do the job instead.

As for the boost, just adjust the values in the table all the way around, or should it be in increments of some kind?

[Simon]

You can start with a single value (start low and work up)

This will get a good starting point.

Then you might find you need to taper the values based on boost and RPM to get a smooth boost level.

Often if you are using a 3d table you will drop back the duty cycle on any boost levels above the target so as to avoid over boost.

[andreas27s]

Still need some help figuring everything out with this. What are the values for the rpm, time (whatever its called), as well as the other values in the settings before you get to the duty cycle table? Once you get to the duty cycle what values would be acceptable to input?

What was is there to setup the fittings so that you get the most consistent boost values or get the system to work the best? Is there a diagram or some place that I can find the correct way to hook it up, because I have seen multiple setups for routing the boost lines

[EFMotor]

Earlier there was a a chapter on boost control solenoid wiring and how to hook it up to both external and internal wasegates in the Vi-pec manual. But I can't find it now. Looks as it has been removed by some reason. Maybe some of the Vi-pec tech guys can tell us why this are not present in the manual anymore.

[EFMotor]

Here is a map of the lines for external wastegate.

[andreas27s]

I will have to check my setup again to see if I have it wired like that, but thank you for the schematic of how it is supposed to be hooked up since I know there are multiple ways. Another question I have is what if I do not have the port on the turbo like shown and I am using the intake manifold as a pressure source instead? Is there a different way to hook it up or will it still work like this one?

Lastly, what are the typical numbers that you would put in the table to get the boost where you want it? I want to set it to 18psi as that is what the car was tuned for when I had the manual boost controller on it, although I bought the new electronic boost controller after it.

Thanks for any help too.

[Dave Kriedeman]

Hi,

have you setup a boost table yet.

Normally you would use RPM on your X axis and TPS or MAP on your Y axis.

I normally use RPM and MAP.

SETTINGS :

BOOST MODE = Open loop

RPM ACTIVATION = dependent on turbo charger as to when it will make boost.

I normally set this value low to make sure the solenoid is active before the turbo starts to build boost, just my preference).

1500 - 2000 rpm.

MAP ACTIVATION = 100 Kpa.

DEACTIVATION TIMEOUT = 0

Under the auxillary output that you have assigned to boost solenoid, set the frequency to 20 Hz.

Create a boost table with the Y axis set to MAP,

Add MAP values to the AXIS to the value of the boost pressure you wish to run,

EG:

MAP Kpa

99 = 0 TO ALL RPM LOAD POINTS

100 = 0 to rpm points below 1500 and make the rest of the cells 10

120 = 0 to rpm points below 1500 and make the rest of the cells 10

225 = 0 to rpm points below 1500 and make the rest of the cells 10.

Do the same for all of the remaining RPM / MAP points all the way to your desired final boost level, of 18 PSI. (224 Kpa absolute) or 124 Kpa if your using MGP as your AXIS.

You need to then do a pull on the dyno or road test the boost.

YOU MUST DATA LOG YOUR RESULTS.

Look at the data log and see at what rpm the turbo starts to make boost and also where the turbo actually achieves your boost level you are chasing.

If you find you do not achieve your desired boost level, keep making the duty cycle value higher in steps of 5 to 10 at a time.

EG: if you find the turbo is laggy down low in the RPM band you can try to add to the duty cycle in that load area.

So if 10 % duty is too lazy step it up to 20% and see if this aids the low end response ( NOTE, big turbos will be laggy even with a high duty applied).

As the turbo becomes efficient and develop boost rapidly you may find that you have to reduce the duty value in your table to control the desired level and to avoid overboost.

You may end up with a table that has a value of 45 in all cells from 2000 rpm to max rpm and upto 150 Kpa to achieve your boost level down low and have a value of 20 in the higher MAP areas of your table, to help stabilise the boost to 18 psi.

Basically it is an adjust and test exercise, and data logging will help greatly reduce the time it takes to achieve your goal.

There are no magic numbers anyone can give you that will work straight up, to many variables exist.

Remember to keep an eye on the AIR FUEL ratio and monitor the ignition for detonation.

Tuning your boost curve doesn't mean that the boost charactoristics will be the same as when it was tuned previously.

EG the engine may make more boost earlier than before and that part of the ignition or fuel map may not be tuned correctly for that particular boost level.

Hope this helps.

Regards

Dave.

[andreas27s]

Dave,

Thanks for the help as that helped tremendously! I was able to set it with the values you gave me and finally be able to achieve boost for a change. The values for boost by gear were at the standard setting as well, with alternating -99% and 64%. Are you able to explain the boost by gear option as well? I know there is more load on the engine when in 3rd and 4th gear, so the engine will achieve higher boost in those gears and with the log it seems like 1st and 2nd gear does not allow for boost at the same RPM levels as the higher gears. I would like to at some time be able to use this feature to have everything be consistent when driving the car.

I looked at the log and it gave me some good data, but the turbo was not entering boost until a lot higher RPM for whatever reason. I increased the DC numbers down low and declined after I saw a consistent boost level on the log, which was in the higher RPMs. I will only be trying to make it up to 17psi though, since I know it was tuned at 18psi and the engine can handle it with ease, I just want to be safe with the engine. It's not going racing or anything like that, more of a regular driver with a lot of fun driving it.

Are you able so show me what a DC table looks like so I can get an idea of how much the decrease would be to stabilize boost? This would help so I know what it would look like since it seems a little weird to have a bunch of high values and then lower values later. I understand the theory, would just like an example so when I do my own, I know my values aren't ridiculous.