Setting up Boost on wideband

[z0tya]

Try this:

analog input curve 0 (0) 0
analog input curve 1 (15) 0
analog input curve 2 (30) 0
analog input curve 3 (45) 14
analog input curve 4 (60) 36
analog input curve 5 (75) 57
analog input curve 6 (90) 79
analog input curve 7 (105) 100
analog input curve 8 (120) 122
analog input curve 9 (135) 143
analog input curve 3 (150) 164
analog input curve 11 (165) 186
analog input curve 12 (180) 207
analog input curve 13 (195) 228
analog input curve 14 (210) 250
analog input curve 15 (225) 255
analog input curve 16 (240) 255

analog input calibration 32
analog input offset        0

if i make good, it will show absolute pressure in kPa

[Ellisd]

Will looks like we're very close now! the analogue curve works a treat! it's about 5 kPa out which is almost nothing so i'm sure a little tweak will sort that.  Here's a pic from the log.  Max boost on my greddy controller was around 0.99 bar boost, 199 kPa total pressure  thanks everyone for your help, and sorr for being such a pain lol

[[email protected]]

If you want to take some raw readings - pure analog values and bear in mind local air pressure when you take your base reading, I use the BBC's weather http://www.bbc.co.uk/weather/5day.shtml you will have to set your location.
Take a look at the heading Current Nearest Observations: and there's an entry Pressure (mB): which when I looked a minute ago read 1014 this translates to 101.4kpa so that would be the base point to work from on the day you take the readings.

[PeepPaadam]

It's great to see that you guys got the boost logging working! Round has very good capabilities but there's definitely need to make them more easily usable. Logging boost, rpm, MAT additionally to lambda and EGT is very beneficial.

[Ellisd]

Yes compaired to other gauges I have looked at on the market the VEMS beats them hands down on features and price.  Yes the software is a little "raw" shall we say.  But thanks to the people on this forum you can overcome that. 

Can i just check I've under stood you last post correctly Rob?

I understand the difference between relative and apsolute pressure.  When looking at the BBC's website it's saying here in Newcastle it is 1012 MB which is near enough 101 kPa so when i power the gauge up without the engine runing i should see 101.

My boost gauge is relative and show's 000 at startup.  I'm guessing this will show zero at all absolute pressures, 99, 100 101 etc. Show when my boost gauge shows 1.10 Bar (110 kPa) it means 110 above atmospheric?  So today that will be 211 absoulte (101 + 110 added by the turbo).  And this should be what my Vems display should read/

[[email protected]]

Thats it pretty much spot on

[Ellisd]

Every day's a school day ha ha ha

[[email protected]]

the problem comes with the accuracy of the gauge that you're measuring the displayed boost with - I'm guessing that the Greddy controller's sensor is very accurate, but the display seems to be compensating for barometric changes.

[Ellisd]

Yes that's what i'm thinking.  The greddy gauge must just take the initial reading as zero and build ontop of that.  I know the 2 gauges will show slightly different readings, but if I calibrate the curve correctly using the BBC's website I'll know both will be right.  1.1bar on the greddy will always be 1.1 over atmospheric.  So it wouldn't really matter if my logs showed 210, 211 or 212 kPa's if it's setup right initially both will still be right

[[email protected]]

Yes, there will be a little bit of a deviation.
Or wait until the BBC tell you that the air pressure is 1000mb and get out in the car double quick

Rob

[Ellisd]

well i think i'm finally sorted!!!!!!!!!!



I think I have to tweak my boost controller to smooth out the little hump at around 4K but aprt from that i'm well happy.

[[email protected]]

Nice work, I think this is the most detailed write-up we've had on getting all of the logging features working.

[Ellisd]

Got there in the end lol 

[ranz]

Got there in the end lol 

Witch firmware are you using? and can you send me your round.ini file, today I tryed to set my boost loggig but without result, something is very wrong and I don't know what.
Right now is the only certain thing MAP-s 100kPa output voltage, it's 2,18V (audi S2 original 200kPa MAP). I have to by somekinde of precise pressure gauge to measure all other pressure points (as I understand, without that information I can't make it work right).

EDIT:
This is what I could measure today (with not very precise pressure gauge). Settings are: linear curve, calibration is 255, offsett is 0
Like I said on athmospheric pressure it shows 2180 mV @gauge 1300
@ 150kPa - 3200mV @gauge 1420
@ 200kPa - 4560mV @gauge 1585
With disconnected analog in (4V) shows gauge 1529 and to ground 1040

Now, what settings should I use to see @ megatune pressure in kPa, for logging I know how to do it, but I can't make the gauge in megatune show me these numbers what I want to see.

From these measured points and other information what I had, i made some calculations and came up with this kinde of numbers:
@ 0kPa - 0mV @gauge 1038
@ 10kPa - 191mV @gauge 1064
@ 20kPa - 412mV @gauge 1090
@ 30kPa - 633mV @gauge 1116
@ 40kPa - 854mV @gauge 1143
@ 50kPa - 1075mV @gauge 1169
@ 60kPa - 1296mV @gauge 1195
@ 70kPa - 1517mV @gauge 1221
@ 80kPa - 1738mV @gauge 1248
@ 90kPa - 1959mV @gauge 1274
@ 100kPa - 2180mV @gauge 1300
@ 110kPa - 2401mV @gauge 1326
@ 120kPa - 2622mV @gauge 1353
@ 130kPa - 2843mV @gauge 1379
@ 140kPa - 3064mV @gauge 1405
@ 150kPa - 3285mV @gauge 1431
@ 160kPa - 3506mV @gauge 1458
@ 170kPa - 3727mV @gauge 1484
@ 180kPa - 3948mV @gauge 1510
@ 190kPa - 4169mV @gauge 1536
@ 200kPa - 4560mV @gauge 1585

Today I bought one presice boost gauge also (vaacum/boost was very expensive), now i will measure all these points and see do they match.

EDIT2:
Now I came up with formula with what the showed value is going to be in kPa.
Value - 1038 / 2.62 = X kPa
With that formula I got the most lower fault percentage. Now, boost loggign should work with that... but where should I put that formula to get kPa reading in megatune?

[Ellisd]

I'm using the latest firmware, i think it's something like the 12/2008?

In all honesty z0tya did all the hard work.  I just fine tuned the table he posted on here

I'll send my INI file tonight when i get in from work.  The boost is pretty much spot on now, but i still need to tweak the vacuum as it goes wrong at the very bottom end (only a 5kPa out though).  The fine tuning was really guess work, I used a footpump and my electronic boost controller to get an accurate figure (i went up in steps of 10kPa)  Then i was a case of altering the figure in the table closest to what I wanted and see what change it made.  It was trial and error