legacycentral bbs

This may be of some help....or at the least be an interesting read.
http://www.main.experiencetherave.com:8 ... gement.pdf

This scan looks new and exciting... good find, Josh!

I have never found such a collection of relevant information on a single subject until I visited Legacy Central

Update:

I received the pressure sensor today, and actually got a chance to work the entire day on the project. I got the sensor hooked up and tested, then calculated a lookup table and now have it reading in PSI very accurately. I added a peak hold feature that automatically keeps track of the largest boost value read so far. Both current and peak boost are displayed simultaneously, and are way more responsive than necessary.

So far, so good!

Got the wastegate control solenoid out of the Legacy and into the garage, and am now preparing for a series of experiments that should result in a closed-loop boost control system.

Want a photo? Check out the peak pressure created by my solder sucker


^^^ This is the proto board setup. Lots of LCDs to try.


^^^ This is my favorite display, it's a vaccuum-flourescent. It's also very expensive, and I've only got one, but damn it looks good. Tough to get a good photo of it...

Anyway, I do believe tomorrow I will have more time to work on this. I've got the solenoid sitting here to experiment with, and really think I'll have something tested in my car tomorrow afternoon... you can bet I'll post if thats the case.

sweet lookin

That's awesome! So I take it LegaCU is the tentative name for it? What other LCD's have you got to test with?

Swwwwwwwwwweeeeeeeeeeetttttttttt

Yeah, I'm just calling the whole project LegaCU for lack of inspiration... even though the whole boost control system might be a completely separate product.

The other LCDs I've got to play with are standard displays, 4x16 char, 4x20 char, 2x8 char, and 1x6 char. The VFD is a 4x20 char and damn it looks good. Unfortunately, that display is $150 new, parts cost! The other LCDs range between $10 and $30, much more reasonable. But since I had the VFD lying around, I wanted to use it for the prototype. Freakin' sweet.

Oh, and I can make a boost bargraph on these displays I plan to use so this will also include a visual representation of the boost level eventually

Lookin' good.

Very nice Chris.

I took a video to show the latest progress... I had the wastegate solenoid hooked up to my garage air compressor and the new pressure sensor, and had the chip open and close the solenoid and read the resulting pressure from the compressor. Got the bargraph working, too. Works out to be pretty exact, at 1 psi per pixel, with 30 pixels wide. The characters are blocked off in 5 pixel sections, so it is very easy to read.

Unfortunately, I have nowhere enough webspace to post the video (MPEG 10MB, 640x480). Anybody have 10 MB of webspace for this video so I can post a link here?

By the by, I'm quickly and accurately reading in PSIg from the Subaru MAP sensor now. It has a usable range of 0-16.5 PSIg, or 0-33.2 PSIa, and matches beautifully with the Honeywell sensor within it's range.

So if you're planning on running more than 16.5 PSI on your Legacy, you'd probably want to invest in the Honeywell pressure sensor upgrade (0-30 PSIg), which adds approximately $35-$40 to the product.

If someone knows of a good, inexpensive, readily available automotive-grade pressure sensor that has a comparable range to this Honeywell I have here, please let me know a part # and source so I can get one for experimentation. For now, I will run a boost line through the firewall to the Honeywell sensor, as it is not rated for under-hood temps. Digi-key did not appear to have any options that included those temperature ranges, someone please correct me if I am wrong here.

Today we will be running final tests on the solenoid, and then we will begin the process of preparing for a run in the car with the closed-loop boost control installed.

I think the GM 3.5 bar sensors are pretty much the standard.

free5ty1e wrote:I took a video to show the latest progress... I had the wastegate solenoid hooked up to my garage air compressor and the new pressure sensor, and had the chip open and close the solenoid and read the resulting pressure from the compressor. Got the bargraph working, too. Works out to be pretty exact, at 1 psi per pixel, with 30 pixels wide. The characters are blocked off in 5 pixel sections, so it is very easy to read.

Unfortunately, I have nowhere enough webspace to post the video (MPEG 10MB, 640x480). Anybody have 10 MB of webspace for this video so I can post a link here?

http://thawa.net/gallery

If that doesn't work e-mail it to Blooough@comcast.net

This sounds interesting.

-K- wrote:I think the GM 3.5 bar sensors are pretty much the standard.

Cool - got a part number? Online source where I can obtain one? Perhaps a datasheet? Is that 3.5 bar absolute, differential, or gage? 5V sensor?


THAWA - thanks, thats a nice gallery site. If you don't mind I'll start putting prototype photos and demos up as I get things to show. How much room do I have before I'm bothering you?


http://www.thawa.net/gallery/LegaCU-Prototyping

Here's the link to my album so far, with high-quality versions of the two photos I posted already. It also has the ~10MB MPEG movie of the solenoid and Honeywell pressure sensor in action (demonstrates the boost bargraph too).

Update: with the solenoid on the workbench and compressor again, I changed the configuration to a controlled leak and successfully regulated the resultant pressure to within 1 PSI with no chamber (i.e. I regulated the pressure in the tube between the solenoid output and the pressure sensor. VERY impressive.)

I believe this will provide all KINDS of tight boost control for us.

I am now working on adding an adjustable throttle position threshold and a separately adjustable partial-throttle boost level.

Perhaps I will take a video of something impressive soon.

what kind of cost ballpark will we be looking at when all is said and done.

the megasquirt park?

or maybe the GReddy or perfect power parks?

If it's reasonable, I'd be all over it.

We're talking the $100-$200 price range, depending on display, pressure sensor, and casing.

Holy crap. That's awesome.

I'd be all over that.

Update: throttle position sensor is being accurately read from idle to WOT. I'm going to try and get an interface coded to allow adjustment of the throttle position threshold for full boost, as well as adjustment of the partial throttle boost level, before I go to bed tonight. Then, I think I can actually go regulate boost in my car exactly the way I want to. If so, I'll do my best to get someone to record a video of my gauges and the boost controller display as I burn through my first 3 gears and hope nobody with authoritah is watching.

free5ty1e wrote:THAWA - thanks, thats a nice gallery site. If you don't mind I'll start putting prototype photos and demos up as I get things to show. How much room do I have before I'm bothering you?

A lot.

http://www.thawa.net/gallery/LegaCU-Prototyping

Here's the link to my album so far, with high-quality versions of the two photos I posted already. It also has the ~10MB MPEG movie of the solenoid and Honeywell pressure sensor in action (demonstrates the boost bargraph too).

Very cool.

Do you still need more ECU's and connectors?

could we get a brief summary of the 24 pages of stuff going on w/this thing?

it sounds really cool. i was up to speed for a while but then you got VERY technical w/Vikash and i got lost.

i think i can handle tuning but not so sure about the R&D.

thanks so much for devoting so much of your time to this.

THAWA - As a matter of fact, yes I could use another ECU/wiring harness set for the male/female connectors. I've got the one Jason sent me but will probably not butcher it up until I've got two. Backups are good.

Greg - For now, I am basically building an electronic boost control system with all the fixin's:

*Digital display of boost
*Boost bargraph
*Resettable peak boost hold, reading & bargraph
*Digital display of throttle position
*Adjustable throttle threshold for full boost
*Separate partial throttle boost setting
*Separate "overboost" or "scramble" boost setting (with button to toggle overboost conditions)
*I'll probably even put a MAF readout in CFM so you can see what kind of airflow your turbo is pumping out
*I also hope to have enough resources to read intercooler inlet and outlet temps and display them digitally / intercooler efficiency can be calculated and displayed too - all using two-cent thermistors.

And, it will work up to 16.5 psi with the stock Subaru Legacy Turbo MAP sensor. Or, with the extra pressure sensor, it can read and regulate up to 30 psi. And, it just uses the stock Subaru Legacy Turbo wastegate solenoid to control the boost.

Tuning comes later, when I build the probably separate LegaCU product that will allow table-based tuning of airflow values and injector timing. I plan to make a wideband O2 sensor-based closed-loop tuning feature, with a table of desired air/fuel ratios, for the ultimate in control.

Not sure if the closed-loop electronic boost controller needs to be separate or not, but there is a good possibility that regulating boost requires a microcontroller's full attention -- so it will probably end up being another product. There is a possibility, however, that I will figure out how to make one chip do everything without losing any data or making mistakes from being too busy.

I am having trouble locating that GM 3.5 bar map sensor. Here is a 3 bar map sensor, anyone know of a better (and/or less expensive) automotive 3+ bar map sensor I should use? (make sure to include part # and an online source so I can order one)

http://store.summitracing.com/default.a ... search.asp