STD Other Open electronic boost gauge vs altitude

electronic boost gauge vs altitude

electronic boost gauge vs altitude

 
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willbhere4u
Six in a row make her go!

2,507
05-21-2012, 07:46 PM #1
I bought a depo digital boost gauge
http://www.ebay.com/itm/60mm-Depo-Racing...7e&vxp=mtr

I got it but because I live at 5000ft altitude and it was calibrated at sea level it reads -6inHG not zero and reads low boost

the signal from the sensor should be 0-3.5v but its lower because it's set to absolute pressure and at 5k we are about 5-6 less than that

0v= -14.9psi
1v= 0
2v= 14.9 psi
3v= 29psi

Is there a good way to intercept the low signal and boost it by .3 of a volt all the way up the spectrum? in a linear way?

This post was last modified: 05-21-2012, 08:09 PM by willbhere4u.

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
05-21-2012, 07:46 PM #1

I bought a depo digital boost gauge
http://www.ebay.com/itm/60mm-Depo-Racing...7e&vxp=mtr

I got it but because I live at 5000ft altitude and it was calibrated at sea level it reads -6inHG not zero and reads low boost

the signal from the sensor should be 0-3.5v but its lower because it's set to absolute pressure and at 5k we are about 5-6 less than that

0v= -14.9psi
1v= 0
2v= 14.9 psi
3v= 29psi

Is there a good way to intercept the low signal and boost it by .3 of a volt all the way up the spectrum? in a linear way?


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

Captain America
Boostin' & Roostin'

2,221
05-21-2012, 10:48 PM #2
I would throw some resistors at it!
This post was last modified: 05-21-2012, 10:48 PM by Captain America.


1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

Captain America
05-21-2012, 10:48 PM #2

I would throw some resistors at it!



1982 300D Turbo ... 3,6xxlbs, No fan, No AC, Hood Stack, No ALDA, No rear bumper and stuffed front, A/W Intercooled, Injectors by Greezer and HUGE Pre-Chambers with help from OM616 & Simpler=Better, Fuel Cranked up, 60 Trim Compressor wheel, EGT, EMP, Boost 50" Rigid Radius bar on roof Aux tank for a total of 48 Gal Of Diesel! Odyssey PC-1750 Battery in trunk, 27"x8.5"/R14 Maxxis BigHorn Mud Terrains, In June '14 issue of Off Road Mag

AX15 Jeep Trans swap in progress....

aaa
GT2256V

913
05-22-2012, 04:53 AM #3
What it should be doing is have it's own ambient pressure sensor to automatically calibrate itself. Would be annoying to have to recalibrate it all the time.

You can build that with a second sensor and some kind of circuit connecting it to the first to automatically take care of the offset.
aaa
05-22-2012, 04:53 AM #3

What it should be doing is have it's own ambient pressure sensor to automatically calibrate itself. Would be annoying to have to recalibrate it all the time.

You can build that with a second sensor and some kind of circuit connecting it to the first to automatically take care of the offset.

willbhere4u
Six in a row make her go!

2,507
05-22-2012, 10:42 AM #4
I was thinking Arduino board??? and just let it take the input value and add a set amount to it and send it as an output to the gauge! But I haven't messed around with this stuff yet

I like your Idea more it would calibrate for altitudes changes witch I encounter a lot when driving in the Rocky's

I live at 5k and drive up to 8k pretty often and the occasional 14k trips
This post was last modified: 05-22-2012, 11:24 AM by willbhere4u.

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
05-22-2012, 10:42 AM #4

I was thinking Arduino board??? and just let it take the input value and add a set amount to it and send it as an output to the gauge! But I haven't messed around with this stuff yet

I like your Idea more it would calibrate for altitudes changes witch I encounter a lot when driving in the Rocky's

I live at 5k and drive up to 8k pretty often and the occasional 14k trips


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

aaa
GT2256V

913
05-22-2012, 02:57 PM #5
It would be simpler than an arduino. Probably just a few zeners and resistors, that's all it'd take to combine two voltages together.
aaa
05-22-2012, 02:57 PM #5

It would be simpler than an arduino. Probably just a few zeners and resistors, that's all it'd take to combine two voltages together.

sassparilla_kid
diesel > all other fuels

1,618
05-22-2012, 08:47 PM #6
My boost gauge is mechanical, but I have the same problem. It reads -1inHG when the car isn't running, so I guess that means it is reading about 1psi lower than it actually is once boost builds up

-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!
sassparilla_kid
05-22-2012, 08:47 PM #6

My boost gauge is mechanical, but I have the same problem. It reads -1inHG when the car isn't running, so I guess that means it is reading about 1psi lower than it actually is once boost builds up


-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!

willbhere4u
Six in a row make her go!

2,507
05-22-2012, 08:48 PM #7
(05-22-2012, 08:47 PM)sassparilla_kid My boost gauge is mechanical, but I have the same problem. It reads -1inHG when the car isn't running, so I guess that means it is reading about 1psi lower than it actually is once boost builds up

-6inhg is = 2.9 psi so probably only about 1/2 psi off that's not to bad

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
05-22-2012, 08:48 PM #7

(05-22-2012, 08:47 PM)sassparilla_kid My boost gauge is mechanical, but I have the same problem. It reads -1inHG when the car isn't running, so I guess that means it is reading about 1psi lower than it actually is once boost builds up

-6inhg is = 2.9 psi so probably only about 1/2 psi off that's not to bad


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

sassparilla_kid
diesel > all other fuels

1,618
05-22-2012, 08:56 PM #8
Oh well then, I guess its not that bad at all lol

-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!
sassparilla_kid
05-22-2012, 08:56 PM #8

Oh well then, I guess its not that bad at all lol


-1982 300D Turbo, 280k miles, ALDA apparently maxxed, fram 8038, 12 lbs boost, non-egr manifolds, W/M injection, 4 brake light mod, Gen II w126 front rotors/calipers, 4-speed swap
In the works: A/W IC, adjust pump, turbo rebuild (w/60 trim comp wheel)
-1980 300SD, 110k, project car. Goal is to get it lookin' like it did on the showroom floor (body and interior wise, not necessarily under the hood )
-1974 240D, FRESH PAINT!!!!!!

willbhere4u
Six in a row make her go!

2,507
05-23-2012, 09:44 AM #9
I read somewhere that there might be an adjustment on the back of the gauge under a sticker so I'll check that out this weekend before I get carried away

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
05-23-2012, 09:44 AM #9

I read somewhere that there might be an adjustment on the back of the gauge under a sticker so I'll check that out this weekend before I get carried away


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

willbhere4u
Six in a row make her go!

2,507
05-30-2012, 12:12 PM #10
I found a tiny Allen screw pot on the back of the boost gauge and turned it all the way over and now it at -2 not -6 so that's close enough for meBig Grin

1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
05-30-2012, 12:12 PM #10

I found a tiny Allen screw pot on the back of the boost gauge and turned it all the way over and now it at -2 not -6 so that's close enough for meBig Grin


1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running

 
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