Homemade Boost Controller with Diagrams - Is this possible?

[ACCLUDE91]

Delima: I want to electrically control the boost from the driver seat without spending $300+ on a digital boost controller and without running vacuum lines for the cheaper manual boost valve

Objective: To be able to go from low boost to high boost (and vise versa) at the flip of a switch from the driver seat for as cheap as possible (less than the manual boost valves).

I think I'm gonna go with my own homemade boost controller. I'm sure I'm not the first person to think of this but it makes sense and it's cheap (I like cheap things). I hope this works like I think it will. Please correct me if you see any issues with this setup.

Here are the cheapest prices I've found so far. If you can find any of this for less, please PM me and I will edit this list.

Required Parts:
12V 2 wire Boost Solenoid - $5-10 at your local junkyard
(2) 12V Adjustable Boost Pressure Switches - $30 shipped for both on ebay - http://motors.search.ebay.com/boost-...h_W0QQfromZR40
(2) SPDT 12V Switch - $2.29 Radio Shack (I have one laying around) - http://www.radioshack.com/product/in...entPage=search
(3) Diodes - $1.79 Radio Shack (I have some laying around) - http://www.radioshack.com/product/in...entPage=search
Vacuum adapter tee adapters - $4.29 NAPA (I have some laying around) - http://www.napaonline.com/MasterPage...ption=Hose+Tee
about 5' of vacuum line - $6.25 ParagonPerformance (I have some laying around) - http://www.paragonperformance.com/Silicone%20hose.html
(3) Tri-Color LED's - $2.98 Radio Shack - http://www.radioshack.com/product/in...entPage=search
(5) 330 ohm resistors (for LED's) -$3.96 Radio Shack (I have some laying around) - http://www.radioshack.com/product/in...entPage=search
about 35' of wire - $4.99 Radio Shack (I have some laying around) - http://www.radioshack.com/search/ind...4.00+-+%245.99
(5) Ground spades - $1.69 Radio Shack (I have some laying around) - http://www.radioshack.com/product/in...entPage=search

So grand total if you were to purchase everything from scratch - $65.44

My cost since I have a lot of this already - $37.98 (the $30 pressure switches being the biggest expense)

As far as I know, this could be the cheapest way to electrically control boost. Best of all it's a homemade kit.

Like I said, if anyone can find cheaper prices on any of these items, let me know and I will update this thread.


Here's a diagram of the Vacuum lines:

Basically, instead of running the line from the intake manifold to the external wastegate (or manual boost valve for you guys that have them), it gets tee'd off and runs to the two pressure switches and to the boost solenoid. Then from the solenoid to the wastegate. Pretty basic and it can be done with less than 5' of vacuum line and some tee adapters. Each pressure switch is adjustable from 4-25 PSI. I figure one can be set at about 8 PSI for daily driving and the other around 12 PSI for those "spirited" driving moments. It follows the usual wastegate operation. The wastegate will stay completely closed because it will not see any pressure in the vacuum line until the solenoid is activated. The wastegate I have is a 35mm external set to 7 PSI. Anytime the solenoid is activated and supplys the wastegate with 7 PSI or more of pressure, it will open and vent the extra exhaust pressure. Once the solenid closes, the wastegate closes and stays closed until the next time the solenoid is activated.

Here's a diagram of the electrical connections:

Basically, there is a manual switch that allows you to chose from one pressure switch (8 PSI) or the other (12 PSI). Depending on which pressure switch is chosen determines what boost level I can hit (pre-set switches) There are three LED's that can display 3 colors each. One is a power indicator and will light up green if the 12V source feeding the entire circuit is good, or it will light up red if the circuit fails for some reason (uses the relay to do so). Another LED is for Hi/Low boost indication and will light up red if the low boost pressure switch is selected or it will light up green if the high boost switch is selected. I'm choosing red for low and green for high because at the track it will always be in high boost and I'd rather have all the LED's lighting up green so that incase the power cuts out, the red LED will stand out more to alert me of an issue. The third LED (does not have to be tri-color) is simply used as a wastegate activation notification. Anytime the boost solenoid is supplied with voltage (activated) the LED will light up using the relay to isolate circuits. (I have a blue single color LED laying around so mine will light up blue any time the wastegate gets activated). That's basically just another safety precaution. If at any point in time the boost gets higher than the set level and the blue LED does not come on, I know something is wrong whether it's a pressure issue, wiring issue, whatever.



Overall layout inside the car:
No pictures yet. I'll update this thread when I actually get around to doing this.
The hi/low switch is going to be mounted in a custom panel below the radio (where the cubby pocket is).
T he 3 LED's will be mounted at the top of the gage cluster for easy driver viewing and also hiding them from others.
The two relays will be bundled together for ease of installation and to make troubleshooting easy and they will be placed behind the dash/center console area.

Overall layout under the hood:
Again, no pictures but I will update later.
The pressure switches will be mounted in fairly close proximity to the manifold for accuracy.
The boost solenoid will be placed within close proximity to the wastegate but away from the turbo heat.


That's pretty much it. It's not a digital controller, but it is an electrically selectable boost controller that will change between pre-set boost level at the flip of a switch and provide the driver with visual feedback about what the system is doing. I'd personally reather spend $37 on this setup instead of on a manual valve.

Like I said, I can't be the first person to think of something like this, but I have not seen it posted anywhere so figured I'd take the innitiative. Let me know what you guys think, possible problems, and any info you can give on this setup. I will be doing this in the near future and will keep you updated. PLEASE FIND CHEAPER PRICES ON THESE PARTS! This kit may be do-able for less than $45 with the right prices on parts!

[ACCLUDE91]

Ok, after talking with some guys on HMT, I got the idea to use a comparator chip. Still working out the details, but a rough diagram is:



Here's the chips internal specs:



And it really seems do-able and cheaper!

Another idea added on to the basic boost controller operation is to use cheap LCD that uses the MAP signal converted to milivolts to display the boost value. Since the MAP is linear this shouldn't be too hard to do.

Let me know what you guys are thinking.....

[ACCLUDE91]

OK, another update.

You know we can afford boost spikes on our hondas, so the way it's set up so far won't work because it will cause boost spikes. I'm working on a simple circuit board with some of the guys from HMT to use MAP input, TPS input, Injector Pulse, and RPM input to send a pulse width modulated signal to the solenoid based on the boost pressure selected and the engine load. If anyone on here has experience with electronics and computer chips, please help out in any way you can. It seems like it's do-able but some kinks need to be worked out.

[cp[mike]]

not knowing TOO much about boost, both diagrams look good. the first diagram looks to be designed correctly, and theoretically should work.

post up more details about the pulse generator circuit, i have electronics experience and id love to see your progress, and i may be able to contribute some

[92ex]

yeah, so if you manage to get this thing working correctly, I definitely want one

[ACCLUDE91]

I'm trying to plan out a basic circuit board with a standard Serial connector. That way programming it in the car would be pretty straightforward. It might have to be microcontrolled and I'd have to pull out all my old programming books to make it work but it is possible. If I'm going as far as microcontrolled then I might as well add some RAM to be able to datalog through the serial connector. If I can keep it simple enough it shouldn't be too expensive. I will keep this thread updated.

Again, if anyone wants to help develop this thing, just say something. If it works good and its cheap, it may be a good business opportunity down the road.

[d112crzy]

whoa. I was reading your thread in hmt. damn, im uber confused now. lol.

[ACCLUDE91]

It keeps getting more complex.

I just wanted to use a few things I had lating around a few small dollar items to try to piece together an effective boost crontroller that I could change from the driver seat without using the manual valve. But now its turning into a an all out project.

It went from
- throw a few things together and easily wire them up -
to
- build a circuit board complete with processor and PC interface, program it to work with the board, the PC, and all the connections to the car, install it in the car, program the proper values for proper operation based on its input, and so on.... -

If it gets too expensive then I'll just break down and get the Jaycar controller. Right now it looks like a budget of less than $100 which is pretty good being the prototype and all. I'd rather build it than buy it so that's what I'm trying to do here.

If it does get done and it is successfull, I'm sure it could be sold in "kits" for well under $100 and I'm sure you know that no other electronic boost controller could touch that price.

[92ex]

If it does get done and it is successfull, I'm sure it could be sold in "kits" for well under $100 and I'm sure you know that no other electronic boost controller could touch that price.

Word. If you need help, I can, but I will let you know, I am not very electrically inclined.

[ACCLUDE91]

It will take the effort of many people to get this to work right.

I just registered www.homemadeboostcontroller.com

Anyone know the absolute cheapest hosting company and some free forum software? I want to get this thing going soon.

[gloryaccordy]

I think you'd need to run more than one fuel and ignition table to play it safe. I've thought about stuff like this too...but I'm not turbo yet...

[cp[mike]]

i love dreamhost.com, i originally signed up for 77cents a month, but its 12 a month now... another great option is Doteasy.net which offers very nice free hosting, i used to use them all the time.