How should the boost gauge read?

[BlueFlash]

I just installed the boost gauge today. It works but when the ignition is Off, it reads 0 then when I start the ignition, it reads -0.5, as I accelerate, then it goes up to 1.0 and won't go higher than that. Does this sound right?

* Registered users of the site do not see these ads.

[Skidd]

Yes.. That sounds right to me.

Remember, your guage is reading the pressure difference between your intake and the ambient air.

When the motor is off, there is no boost or vacume. So the guage reads 0.0

When at idle, the motor is creating vaccume, so your guage reads the negative.

Under hard driving, the turbo spools up, and starts to create pressure, so the guage reads in the positive.

And.. 1.0 bar is equal to 14.4psi. and IIRC, the WRX bosts to a max of about 14 psi.

[syntrix]

that's kinda right... it's pressure above what your atmospheres are at your elevation.

so at sea level, you read 14.7 psi (1 bar) but are producing 29.4 psi (2 bar). But it does read the "difference" between outside air and the intake, so you would definately see 1 bar at full boost.

Hope I confused ya a bit

[BlueFlash]

that's what i thought, it was the vacuum... Thanks guys.

I was playing Gran Tourismo 3 and see how the gauge reads in the game. almost the same, but a lil more boost than 1.0, since it's a WRX STi, it boosts up to 1.2-1.3

[syntrix]

Originally posted by BlueFlash
I was playing Gran Tourismo 3 .....

crashing is not real in that game, so don't try it in your real car

[subeerex]

Any one knows how to read the digital boost-gauge by Cyberdyne?! I just installed it but am confused by what's going on. OK, before I go on...you probably guessed, I'm new at this. Now, that said...at a stop position/stoplight, the gauge reads something like 15.6 or something but what concerns me is that when I accelerate it goes back (numericaly) to zero(0) and then, as I keep on accelerating (automatically) it starts to climb again. If I take my foot off the gas (at freeway speed for example) it drops again and past zero to twenty three (23.--something) and would climb if I give it gas! I haven't driven hard lately so I don't know how far it would climb.
Just like the previous thread, is this normal and which part of the reading is the boost...exactly?!
Is there anyway to find out how much boost you're running without max'n up your driving or using any other gadgets??!
I just don't know how to read the boost-gauge, someone suggested to put one in so I know what's going on with the boost levels. Don't know nobody that has one (especially on a Rex) so I couldn't look at one before installing mine.
Would someone, please...enlighten me!!!

[bobturismo]

Originally Posted by subeerex

Any one knows how to read the digital boost-gauge by Cyberdyne?! I just installed it but am confused by what's going on. OK, before I go on...you probably guessed, I'm new at this. Now, that said...at a stop position/stoplight, the gauge reads something like 15.6 or something but what concerns me is that when I accelerate it goes back (numericaly) to zero(0) and then, as I keep on accelerating (automatically) it starts to climb again. If I take my foot off the gas (at freeway speed for example) it drops again and past zero to twenty three (23.--something) and would climb if I give it gas! I haven't driven hard lately so I don't know how far it would climb.
Just like the previous thread, is this normal and which part of the reading is the boost...exactly?!
Is there anyway to find out how much boost you're running without max'n up your driving or using any other gadgets??!
I just don't know how to read the boost-gauge, someone suggested to put one in so I know what's going on with the boost levels. Don't know nobody that has one (especially on a Rex) so I couldn't look at one before installing mine.
Would someone, please...enlighten me!!!

if you have a WRX or STI, you shouldn't be boosting past 14.5 or 13.5 PSI. (1 bar)


AT idle, you should read in the negative, negative pressure = vacuum. The turbo isn't doing anything and the pistons are creating vacuum (like a non-turbo engine)

Under acceleration your turbo compresses the air and makes "boost", now you should read positive numbers, it will climb up to about 13-14PSI (1 bar). It will only peak near red line, teh turbo builds more boost as the motor spins faster.

if you accelerate and let of the gas, your boost should drop to vacuum (negative pressure), the blow off valve releases the possitive pressure built up by your turbo when you let off.

[AaronB]

If it is like this one I found on the web the VAC light will be on when you are giving very light throttle, decelerating, or stopped and it will be giving the numberical value of the vacuum in In Hg. When the BST light (moderate to heavy throttle) is on it will be giving you the amount of PSI. If both lights light up at once (never seen this gauge before, so I have no idea how it works), it is a crappy gauge (in my opinion) and you will have to use common sense (based on the descriptions above my post) to determine if you are in vacuum or boost

[xS2k]

My brother's boost gauge is not reading VAC, and I follow every step of the instruction below.

https://ssl.autocenter.net/webparts/acatalog/page3.html

He has the autometer cobalt serious boost gauge. It lights up find, but his car is stock Sti, and it shows boost of 25 PSI at 5k, 0 psi at idle, 0 psi at while slowing down. Basically, it doesn't go into VAC whatsoever. Anyone have any idea of why this is happening? Is it my gauge? bad fitting? I checked all hoses and fittings and it seems fine.

Another questions is, what is my oil pressure suppost to read? I've seen it as high as 95 PSI and as low as 20, is this right?

thanks

[bobturismo]

Originally Posted by xS2k

My brother's boost gauge is not reading VAC, and I follow every step of the instruction below.

https://ssl.autocenter.net/webparts/acatalog/page3.html

He has the autometer cobalt serious boost gauge. It lights up find, but his car is stock Sti, and it shows boost of 25 PSI at 5k, 0 psi at idle, 0 psi at while slowing down. Basically, it doesn't go into VAC whatsoever. Anyone have any idea of why this is happening? Is it my gauge? bad fitting? I checked all hoses and fittings and it seems fine.

Another questions is, what is my oil pressure suppost to read? I've seen it as high as 95 PSI and as low as 20, is this right?

thanks

/

25 is WAY TOO HIGH! put the vacuum lines back to stock and eliminate the boost gauge, does teh car get slower? MAke sure it's not leaking.

If tahts the case I'd call the company and see waht tehy say, might be a junk guage.

[xS2k]

^^^^The car feels exactly the same. It's just the gauge does not go into vac, and while idling or downshift, it reads zero boost/vac. Is there another location to hook up the T fitting for a more accurate reading? I'm going to snap a picture to show my location, maybe it's user error...thanks

[Art Pacheco]

Originally Posted by BlueFlash

I just installed the boost gauge today. It works but when the ignition is Off, it reads 0 then when I start the ignition, it reads -0.5, as I accelerate, then it goes up to 1.0 and won't go higher than that. Does this sound right?

I connected the lumination wire but was left with the turbo relay wire. I couldn't find it. Did you find yours? You can also Email me.

[shawnshekari]

Originally Posted by bobturismo

/

25 is WAY TOO HIGH! put the vacuum lines back to stock and eliminate the boost gauge, does teh car get slower? MAke sure it's not leaking.

If tahts the case I'd call the company and see waht tehy say, might be a junk guage.

If it is reading 25 it is prob in inch mercury not PSI.
If that is the case then this might help you.
32 in Hg = 15.72 PSI
30 in Hg = 14.73 PSI
28 in Hg = 13.75 PSI
26 in Hg = 12.77 PSI
25 in Hg = 12.27 PSI <-----
23 in Hg = 10.8 PSI

Help any?

[ChrisL2]

Originally Posted by xS2k

My brother's boost gauge is not reading VAC, and I follow every step of the instruction below.

https://ssl.autocenter.net/webparts/acatalog/page3.html

He has the autometer cobalt serious boost gauge. It lights up find, but his car is stock Sti, and it shows boost of 25 PSI at 5k, 0 psi at idle, 0 psi at while slowing down. Basically, it doesn't go into VAC whatsoever. Anyone have any idea of why this is happening? Is it my gauge? bad fitting? I checked all hoses and fittings and it seems fine.

Another questions is, what is my oil pressure suppost to read? I've seen it as high as 95 PSI and as low as 20, is this right?

thanks

How is it wired? The gauge auto calibrates when you powered on. The gauge should sweep once when turned to ign. It should not sweep again after starting the engine. If it does sweep, it will calibrate 0 PSI to whatever the idle vacuum is.

Here we go. This link has info on what I told another person to do to get the gauge to read right: http://www.scoobymods.com/forums/showthread.php?t=4987