Vent Boost Gauge (Digital Led Bars & numerics)

[mclarenf3]

For my 12v Accessory, I plugged into the Cigarette fuse.

For my ground, I wrapped the wire around a screw on the body.

For the 12v signal for lights, I plugged into the Illumination fuse (however, it doesn't do anything).

For the 0-5v signal for the AFR (what's that?), I left it unattached to anything.

[jproy12]

The 0-5V is for if you have an AFR sensor, if not, leave it hanging!

 

Now what are you guys recording as vacuum during idle and all?

 

JP

[stocklgt]

The 0-5V is for if you have an AFR sensor, if not, leave it hanging!

 

Now what are you guys recording as vacuum during idle and all?

 

JP

 

idle anywhere from 17 to 20 hg depending on load.

when i originally tried to install it i ran all wires to the radio/ash tray light.

i kept my illumination wire when I rewired my power, ground and 0-5v for afr in the drivers side kick panel.

[lossol]

For the 12v signal for lights, I plugged into the Illumination fuse (however, it doesn't do anything).

 

There should be a line in the car that goes to 12V when the parking lights are on. I believe this is the purple wire behind the radio. For the 2006 this goes to fuse # 16 the illumination fuse.

 

When you hook the vbg1 blue line up to this line you can dim the gauge with the parking lights, when enabled in the options menu.

 

Menu option 10:

Auto Bright - Auto adjust brightness using Ambient light or parking lights

Ambient or Parking lights.

 

By factory default this is set to ambient light sensing (auto dimming).

[jproy12]

Thanks for the input lossol!

 

Ill look into wiring that!

 

JP

[mclarenf3]

Nice, so it looks like I've got it wired up properly, but just have to enable it in the menu. Thanks for the input, and the amazing work you've done on this gauge!

 

Just tested mine out on the drive to work today (mostly stop and go). But I was able to get a peak of 20.3 psi while on the freeway, and when idling my vac was only around 2-3. Is that normal? The highest the vacuum got was around 7 or 8 and only briefly after I stepped off the gas (while boost was high).

Edited September 16, 2010 by mclarenf3

[jproy12]

Peaking that high? Are you modified?

 

You should be pulling around 17-20 of In/Hg for vacuum at idle, and while slowing down letting off the gas around 20-23 In/Hg.

 

JP

[BAC5.2]

Nice, so it looks like I've got it wired up properly, but just have to enable it in the menu. Thanks for the input, and the amazing work you've done on this gauge!

 

Just tested mine out on the drive to work today (mostly stop and go). But I was able to get a peak of 20.3 psi while on the freeway, and when idling my vac was only around 2-3. Is that normal? The highest the vacuum got was around 7 or 8 and only briefly after I stepped off the gas (while boost was high).

 

Are you SURE you wired it correctly (to IGN2)? Those are symptoms of a faulty startup procedure.

 

Idling VAC should be in the -17 range, and -22 for high RPM/no throttle.

[BAC5.2]

For my 12v Accessory, I plugged into the Cigarette fuse.

For my ground, I wrapped the wire around a screw on the body.

For the 12v signal for lights, I plugged into the Illumination fuse (however, it doesn't do anything).

For the 0-5v signal for the AFR (what's that?), I left it unattached to anything.

 

Yep, you wired the 12v ACC wrong.

 

You need to use the IGN2 fuse. The Cigarette fuse cuts power during cranking, and doesn't allow the pressure sensor to auto-calibrate. That's why your readings are off.

[DrSpeed]

The 0-5V is for if you have an AFR sensor, if not, leave it hanging!

 

 

 

Wait, we can't tap into the factory O2 sensor?

[jproy12]

^^ I wouldn't know... Ask lossol, he would know, but its for an aftermarket wideband sensor.

 

JP

[stocklgt]

Wait, we can't tap into the factory O2 sensor?

 

I knew i read something that says stock 02 sensors are not accurate.

 

taken from the romraider website - "A Wideband O2 Sensor is almost, but not quite, essential. The stock O2 sensor is not accurate when the car is under boost. Cars with 16-bit ECUs use O2 sensors that are only accurate in a narrow range around 14.7:1 AFR under any conditions. Cars with 32-bit ECUs use O2 sensors that are accurate over a wider range, but they still located in the up-pipe, where exhaust backpressure renders them inaccurate. Even if you relocate a 32-bit ECU's O2 sensor downstream of the turbo, they will only read down to 11.1, which is insufficient for most tunes (you could shoot for 11.5:1, but few people do)."

 

Even though the front sensor is a "wideband" type sensor it is not accurate.

[snow05gtRI]

Wait, we can't tap into the factory O2 sensor?

 

you might be able to (the output is setup for a WB 0-5V) if the output is the same, but it's pretty useless to monitor as the post above me described.

[mclarenf3]

Yep, you wired the 12v ACC wrong.

 

You need to use the IGN2 fuse. The Cigarette fuse cuts power during cranking, and doesn't allow the pressure sensor to auto-calibrate. That's why your readings are off.

 

Thanks! I'll fix that tonight.

[DrSpeed]

I don't understand how the factory narrow band O2 sensor is "not accurate"

 

Are you saying that it's slow, has an offset/gain error, or doesn't read the range that you want it to? Running it down to 11.5 at WOT is rich enough, no? And even at that point, the car runs in open loop.

 

Anyone have a way to tap into the factory O2 sensor? All that's needed is to reset the offset and gain on the gauge, right?

 

Thanks. Where are you guys sourcing your wideband O2's?

 

http://www.widebando2sensor.com/Bosch-LSU4.2-5-wire-Wideband-Oxygen-Sensor-(replacement)

 

?

[mclarenf3]

Ok, now it's more like it. -18 is my typical vacuum, and boost went up to about 13 psi.

[BAC5.2]

Doesn't the ECU use the O2 sensor for "rich/lean", and doesn't really care about the numbers? I think there is inherent accuracy concern with a narrowband sensor, but I never really cared enough to look further into it.

 

Some cars use wideband O2 sensors for stock engine control. Volkswagen is one of them.

[DrSpeed]

Hmm....if this is the case, and I cannot use the factory O2 sensor, then I might just sell mine.

[mainelydanks]

just stumbled on this and i want one of these! subcribed for availability....

[snow05gtRI]

Hmm....if this is the case, and I cannot use the factory O2 sensor, then I might just sell mine.

 

sell your factory O2 sensor? or the gauge? the car needs the O2 sensor even if we don't need it for logging reasons.

[stocklgt]

Doesn't the ECU use the O2 sensor for "rich/lean", and doesn't really care about the numbers? I think there is inherent accuracy concern with a narrowband sensor, but I never really cared enough to look further into it.

 

Some cars use wideband O2 sensors for stock engine control. Volkswagen is one of them.

 

 

bingo, i believe it is only used in closed loop situations. the accuracy up to a certain point is pretty decent, but i think after 11.1 you are taking a chance by relying on the numbers. Also, IIRC you can't just buy a wideband 02 sensor, you also need to purchase the controller along with it. There are some decently priced units on the market starting at about $200 with a gauge. Look into the LC1 or AEM Eugo to start with. They sell the LC1 without the DB gauge, which is probably what you are interested in.

Only reason I have one is I was stupid and bought it for my old car. everything just swapped over.

 

*taken from http://www.hondata.com/techclosed.html

 

In closed loop operation the ECU uses one or more oxygen sensors as a feedback loop in order to adjust the fuel mixture. This gives the name ‘closed loop’ from the closed feedback loop. The ECU won’t run in a closed feedback loop all the time, so ‘open loop’ is used to describe the operation of the ECU when the mixture is not being adjusted in this way (usually when the engine is cold or when running under high load).

In closed loop operation the ECU uses the oxygen sensor to tell if the fuel mixture is rich or lean. However, due to the characteristics of the oxygen sensor it can’t tell exactly how rich or lean, it only knows that the mixture is richer or leaner than optimum. The ECU will enrich the mixture if the oxygen sensor shows that the mixture is lean, and lean the mixture if it looks rich. The result of this is that the mixture will swing back and forward around the stoichiometric point.

Edited September 17, 2010 by stocklgt

[BAC5.2]

That's what I thought.

 

Narrow-band is only good for "is it rich or lean?" but not actual numbers.

 

I do know that VW's DO use wideband sensors, and that leads me to believe that they are actually concerned with actual rich/lean values for their engine calibration. Probably explains the relatively high fuel economy their vehicles are capable of. My buddy has a 1.8T Beetle that routinely gets in the 30's, and my wife's old Passat (1.8T with the 5-speed auto) got in the 27-28 range (a solid few hundred pounds heavier, and a few extra ponies than her 09 2.5i Impreza that nets around 26mpg).

[praedet]

Just so you guys know, you are wrong about the stock sensor...

 

You are also wrong about how the ECU sees it. Try reading up in the tuning section. The stock sensor is capable (and accurate) below 11.1. The ECU is just set-up not to trust it there. You can have it read below there, but unless you move it to a different location, no wideband will be accurate richer than that in the manifold/uppipe location...

[BAC5.2]

So the ECU does use numerical data from the narrow band sensor?

[stocklgt]

Just so you guys know, you are wrong about the stock sensor...

 

You are also wrong about how the ECU sees it. Try reading up in the tuning section. The stock sensor is capable (and accurate) below 11.1. The ECU is just set-up not to trust it there. You can have it read below there, but unless you move it to a different location, no wideband will be accurate richer than that in the manifold/uppipe location...

 

Can you link it please? I'm interested in reading more into it. I've seen multiple links that say otherwise...from what i read (not 100% sure where, but rao did make the comment) the stock sensor is MOST accurate in the 11.2-16.5 range, how accurate it is in and out of this range i'm really not sure. In theory it can work, but do you want to rely on an a/f readout when the accuracy has been proven many times to be questionable?

Edited September 17, 2010 by stocklgt