Well, free to the ten most helpful people. When I finish designing and do a prototype run, the most helpful, knowledgeable users will be selected to test them out.

I'm developing a boost controller/gauge and I need feedback, etc...

Nice to meet you all. I'm a fiero nut myself, but I figured this was the place to go to get feedback and advice on a boost controller / gauge I am developing. I hope I can get feedback from some of you guys on my design ideas, hear what you would like to see in a controller, and I may send a free prototype to those who prove most helpful!

As a disclaimer, I want to point out that I am in no way trying to sell anything to anyone, or attempting to advertise. I am designing a product, and want insight from experienced boosters to make sure I don't design a lemon. I currently own my first turbocharged car (gm 3800 v6, aem water/meth, turbonetics t04e, 309ftlbs of torque (haven't tuned past 10 psi yet, have to add an intercooler to someone else's previous setup on this car)

I was appalled by the prices of digital gauges and the more simple boost controllers (I.E. Tru Boost) and decided I would develop something myself for it; given my electronics background.

Let me know which part of this forum would be best to post my design specs and get discussion going on what you guys would like to see, and in four or five months after I make the first prototype I will likely send 10 of these boost gauge/controllers to the people who were most helpful to get an honest review/feel for the product before I begin real production.

I appreciate the help!

Here's what I have so far.

\Here's a google sketchup of what the gauge will look like, currently.



I think I will be able to fit the pcb like this, giving a 1" depth to the gauge at 2 5/8" diameter.



For those of you who are technically oriented, I am using Microchip PIC16F818 MCU and coding in C using MikroC compiler.

The current design relies on a multiplexed 7 segment display array to display the pressure readings.

In my current design (and this is one of the areas that will likely change,) the gauge displays ABSOLUTE pressure, not relative pressure. I.E. if you have twelve points of boost and pressure at your sea level is 14.6, then you would show 26.6 on the gauge. It can work with any bar rating of MAP, I currently have it programmed for a 3 Bar GM map, but the signal is simple enough to change based upon whatever individual car it is going into. The two buttons on the left and right of the face control up and down for the pwm duty cycle sent to the electronic boost controller. Limits of 10% and 90% are established as the minimum and maximum duty cycles. The center **** is a potentiomter which, when turned, displays your chosen "safety psi," I.E. the most boost level you want. This controller will adjust the boost control solenoid down every 5 milliseconds in the event that you exceed your safety psi setting, and this duty cycle is updated and sent to the electronic boost controller 32 times a second. That means in just over 1 second the controller can completely clamp your boost solenoid if there's a problem. The controller scales the boost down, but you have to scale it up manually. It will never exceed your safety psi due a section of the computer code that ensures that duty cycle cannot be increased if you are at the psi you chose manually. I used a physical **** for the safety psi setting, because electronically stored data is not 100%. There is always the rare chance the setting could be lost or corrupted, and the most important setting in a boost controller should be your max safe boost.

This is not a full blown boost controller that does boost by gear, etc... Just a simple controller that will be much more cost effective and dead simple to set up. The only time you would have to alter the boost level, after having set it and obtained it, would be if you significantly changed elevation.

Let me know what you think, very open to logical suggestions.

Here are key areas to discuss:

1) Methods of boost control, safety features you'd like to see
2) Needed response time for boost adjustments (this controller can be adjusted on the fly.)
3) Gauge size, I.E. 2 5/8", 3", 4", etc...
4) Aesthetics suggestions, I'm not artistic.

After this controller is finished, I can begin work on creating digital gauges tuned to individual senders. Suggestions on those would be helpful as well. I'd like to start full digital gauge production within a year.

 

1. boost cut at a set range so if a wastegae fails or something it cuts or alerts
2. Instanly within a sec or two, MBC are a pain but simple , but you still have get out to use.
3. 2 5/8 is what alot of gauge pods hold and dont take up space
4. I personaly like very little clutter and simple. No overly out there gauge that lights up 900 diffrent colors and can put on a laser light show. Just simple.. Just include a good manul that is VERY step by step and user friendly.

 

Excellent idea! I hadn't thought about #1 there. I'll have to think of how to do that. I'm guessing I should put in some kind of counter that alerts if the controller is unable to adjust boost down within a three or four second window. What are your thoughts? That would signify that there was a mechanical problem with the wastegate.

As for #2, adjustments to the boost are perceivable instant. I've slowed the buttons down so that you can go from full closed to full open in less than 4 seconds. Is that fast enough?

I like the 2 5/8 as well. I need to find a supplier that sells that size housing. I also dislike gauges that are too bright, cluttery. It's hard to drive at night with them.

 

If you could make the Thickness of the gauge thin, that would be a plus.

Like 52mm diameter, but from front to back, maybe one inch.

I hate fat gauges.

 

Okay, I'll adjust the seek time on the buttons to make it faster. 2 seconds sound good?

Making it thin should be pretty easy. I'm only looking at a circuit board with 10 resistors, 3 transistors, and three 18 pin dip sockets. That's incredibly small. Should I leave the back open or vented for any heat buildup?

 

actually don't change the timing on it, I reread it say from min boost to max boost adjustment in under 4 seconds right? that sounds good

 

Well, wasn't sure. I thought four seconds was pretty good to put your solenoid wide open. I've set the microchip up so it won't open the solenoid ANY FURTHER after it reads a match between your MAP sensor and the Center **** PSI setting. You could hold the up button all day long and it won't go over the setting you made with the center ****.

 

Thank you both for replying.

 

Most controllers hold the gate closed until the last millisecond then go wide open and modulate from there to control target boost.

4 secobds, even 2, is way too slow for the controller to open the wastegate to control target boost, you'd almost always have a huge spike/overrun before target boost could be controlled

 

Head light wire for auto dimmer

 

You're misunderstanding, somewhat. The 4 seconds was the speed for manual adjustment of boost, if the solenoid needed adjusted. Once you've set your max safe boost, then turned the controller up to that level during a run, it will then remember that setting and only make adjustments down if it sees more boost than your maximum. You would only lose your setting, somewhat, if your elevation changed drastically.

On the other hand, I do like the idea of making it fly wide open then go down very fast to get the controller to auto adjust. The reason I did not set it this way to begin with is I heard there was a problem with controllers overshooting, then undershooting, perpetually.

 

Hmm... I've put some thought into this.

I have two options, use the dimmer circuit from the car to drive it, or set up the gauge with a photoresistor so it adjusts itself without needing a connection to the car.

Which do you guys like more?

Unfortunately, either one of those is going to require a small secondary circuit to make the brightness adjustment linear to the human eye. Not the end of the world, but could make space tight.

 

Updated the sketches to 2 5/8" by 1".

 

Could you simply do gauges, leaving out the controller portion?

I think we could make some awesome things happen at a reasonable cost.. some of the gauges I need are over 400 dollars from westach and they're analog.

 

1) Methods of boost control, safety features you'd like to see
2) Needed response time for boost adjustments (this controller can be adjusted on the fly.)
3) Gauge size, I.E. 2 5/8", 3", 4", etc...
4) Aesthetics suggestions, I'm not artistic.

1. Audio and visual alerts for set amounts of boost. Perhaps an alarm and LED notification if spiking occurs.
2. I think four seconds should be fine.
3. Can't go wrong with 2 5/8" its a very common size and it would make the ease of installing one in the typical pod pillar or gauge holder more simple.
4. Maybe for aesthetics you could include (or sell with) different faceplates and rings to go around the gauge. If someone has a color scheme and they would like your gauge but it doesn't match, then they could easily swap out the faceplate and ring around the gauge to match.

My 2c.

 

Wow, that's crazy spendy.

I *can* make a gauge that has an analog needle, but I need a few more months to research the control method for the particular stepper motor that is used in automotive analog gauges. Most of today's "analog" gauges are actually digital gauges swinging a needle; not joking. They have't been truly analog since the transistor revolution.

If it's just digital gauges, I can do those now. I need to look into the more difficult gauges such as tachometer and speedometer a little more, but boost, fuel pressure, egr, etc... those are very easy to make.

Still, I'd like to finish this project because it involves all the different technologies in one. After that, if I make a little money doing it, I will set up to make regular and digital gauges and start taking orders. That's like a year down the road though.

I agree, gauges are too expensive, and there really isn't anything all that special about the technology. There is more complicated electronics in my coffee maker. It just requires a knowledge of analog & digital electronics, computer programming, and auto repair. Three things I happen to enjoy.

 

1) Audio alert could be *somewhat* difficult, but visual would be super easy. I don't know how you'd see a boost spike with a controller that can clamp the solenoid shut in 1 second, unless the wastegate failed. As mentioned previously, a warning for mechanical wastegate failure is a great feature I need to add.
2) good stuff
3) good stuff
4) I like the idea; I need to find a supplier for 2 5/8 housings, maybe they will have something.

 

5v output to ecu would be nice, also an input for an external scramble boost button would be cool! My big question is why are most boost controller settings in duty cycle as opposed to just setting it to the required boost level?

 

Scramble mode is bad for your turbo.

Boost control solenoids, what a boost controller controls, are a valve that opens and closes 31 to 32 times a second. The period it stays open and the period it stays closed during each of those 31 to 32 times is called the duty cycle.

Required boost level is a function of a number of details. You have a set pressure you would like to see, I.E. boost above atmosphere pressure. At two different elevations, you would have to have the boost control solenoid operate at two different periods of open/closed. A boost controller is like a piece of electronics that herds cats. Atmospheric pressure can change, things can go wrong with your car, etc... It's not as simple as the name implies. It would be more accurate to call them "Electronic Wastegate Actuator Pressure Limiting Device Based Upon MAP Sensor Data Input," but that would confuse people and the product would never sell.

As for the 5v output to ecu, do you mean a 5v signing showing the duty cycle, of a 5v signal showing the boost pressure. The MAP sensor already sends the boost pressure, just add another wire to the ecu. As for the duty cycle, that could be done pretty easily with a linear amplifier.

 

Thanks for clearing that up for me. The 5v output would be to send to the ecu, to prevent the need for either a second map sensor or splicing wires.

 

Not a terrible idea, but I personally would rather splice a wire into the original map sensor connector on my wiring harness than change the way my wiring harness is routed.

Personally, I have a spare map sensor on my car.

 

Sorry to keep adding to this but an output for an optional over boost alarm.

 

I don't need analog per say. I need a few digital, like temp gauges (intercooler in/out which would use 2 k type thermocouples or some common IAT sensor) as well as a digital wideband gauge that would display 4 sensor values at once and some other cool ideas I have.

I simply suck with the electrical side of things lol

If you want, pm me and we can toss ideas around without cluttering your thread, I'd love to help you with a line of quality affordable gauges ranging from widebands to pressure/temp/etc gauges. The car scene really needs a range of gauges that perform well without costing an arm and a leg. The sky's the limit

But I also agree, there's nothing about the technology that would make a temperature gauge 400 dollars, unless the cost of the digital stepper motors for the needle is high but I find that doubtful given the bulk manufacturing of such products, especially overseas.

 

you could use either an LDR or a switched tranny with sig from the dash light circuit
But....
LDR's do cause problems in the car enviroment as light is not fixed and will cause flashing display ( previous experience )

 

I think the majority of people would like it to dim with the rest of the cluster, as opposed to having this one really bright gauge.

The photoresistor is a cool idea but at night inside a car the light the photoresistor sees will be minimal meaning a gauge at full brightness.. and on the highway or a multiple lane road at night means that cars driving past would cause the gauge to randomly dim and brighten, bouncing back and forth. Same thing with a car behind you... the same thing would also happen with street lights, other light sources like signs, light from buildings (especially in a place like downtown Atlanta) would cause all sorts of havoc with the gauge lights.

While a novel concept, I think just having a circuit with a wire you can tap into the dimmer is just the simplest, most reliable thing to do. And the photoresistor would just add complexity and another component that could potentially fail.