If I understand this right there is a spring that pushes a ball into the feed line to the wastegate and keeps pressure on the intake side until the intake pressure overcomes the spring pressure. Once this happens the ball moves and the high boost hits the wastegate and then the wastegate slams open.

Once boost starts to decrease bellow the spring pressue the ball falls back into place and the wastegate still sees the high boost because the pressure is trapped between the wastegate and the ball. As the boost slowly seeps out of the bleed hole the wastegate starts to close. I'm not sure how slowly it really is. Once boost builds back up the process starts all over again.

Does this seem right?

The reason that I'm asking is that this seems to be a pretty much like a switch. If it is I could use a solenoid as the switch and controll it electronically. I believe my DFI has an auxillary output that I can set to go off at a certain map sensor voltage. I'll have to double check that one though. If this is the case I can make myself my own electronic boost controller pretty easily.

 

Well, I looked into my DFI software and there is an optional out put for, the this, VTEC. The great thing about this is that the output can be controlled by TPS, RPM, and/or MAP%. All you have to do is check the box that you want it to look at. And there is a turn on and turn off value for each. The MAP% also has a reverse function that I can tell it to turn on below a value and turn off over a certain level.

So if I tell it to Turn on when MAP% is below 15psi. It not let boost to the wastegate until it sees 15psi, and then it will switch. It will stay like this until the boost goes below the preset value of what ever, 14psi lets say. Then it cuts the boost off to the wastegate again.

This sounds great until I stop at the end of my run and the map sensor see's vaccume and the boost from the pipe gets cut off to the wastegate. Having a BOV should take care of this, but you still want the wastegate to open up to slow the turbo as much as possible. So you throw in the other constraint that the TPS is over 60%(50% off).

So basically it drives at low boost levels when you are normally driving, like you see real boost then anyways. Once you slam on the gas the solenoid cuts off the boost going to the boost gauge since the tps was over 60% and the boost was less than 15psi. Once it goes over 15psi it opens and bleeds off boost until you get to 14psi and then it closes off the boost again. And anytime you let off of the gas it will also open the boost to the wastegate.

The other nice thing about using the map sensor as the refrence is that you are regulating the exact boost going into the engine, not reading boost before the restrictions of the piping, intercooler, and maybe even throttle body.

 

No Comments??? I'm sure somebody has a good idea how this stuff works and how far off I am.

 

So essentially you're trying to make your manual boost controller into an electronic boost controller by using the output of your DFI to control it correct?

Only real difference between electronic and manual is that a elec. has a electric solenoid that opens/closes the "referenced" line before the controller at a pre-set boost level. Only benefit is that the wastegate doesn't creep open slightly in the beginning, which affects spool time slightly. Fancy electronic boost controllers have "fuzzy" logic chips that can do more etc. but that is the basics.

They also make "dual" stage manual boost controllers that have an electronic solenoid to switch between two control units. I'd incorporate something like that so you could have two "preset" boost limits at your fingertips.

Seems like it could work in theory. Try it out and tell us the results.

Mike

 

I'm not trying to make a manual boost controller into an electric, I'm trying to use only an electrical solenoid as a boost controller. I know I'm missing that fuzzy logic, but I'm not sure what exactly it does. It might be the key to making it work, I was hoping someone knew for sure.

As far as the dual stage boost, I was planning on having that as well. I was going to have the power to the solenoid go through a switch that I could turn on or off depending on if I want stock boost levels or the level that I can program into the DFI.

 

Well, I just got off the phone with the Accel Tech line and they said that people do this and it works fine. They also told me that I should try using the nitrous output instead of the Vtec output because it is done in actual kpa instead of %map. Once the engine gets put back togther and on the dyno I'll try it out.