[Alan l.]

Has anyone installed one of these gauges on a 550 yet? Wondering how involved the install is for this car in terms of where you are tapping for boost pressure. I am pretty technical but simply don't have the time to spend hours wrenching on the car nowadays.

Alan

[alextremo]

Originally Posted by Alan l.

Has anyone installed one of these gauges on a 550 yet? Wondering how involved the install is for this car in terms of where you are tapping for boost pressure. I am pretty technical but simply don't have the time to spend hours wrenching on the car nowadays.

Alan

Yes, but not with a mechanical boost gauge. Reads everything from the OBD2 port so install only take a few minutes.

You will need an adaptor if you want to add the mechanical gauge - Dinan sells one for something like $80, haven't seen them anywhere else.

[Alan l.]

Yeah i just saw the diy video and looks super simple.

I am wondering for those of us with the JB tune where it tricks the ECU to make more boost will the obdII signal show actual boost or what it thinks its only making?

Guys with this boost gauge and JB tune please chime in.

Not interested in installing a manual gauge on this car.

Alan

[alextremo]

Originally Posted by Alan l.

Yeah i just saw the diy video and looks super simple.

I am wondering for those of us with the JB tune where it tricks the ECU to make more boost will the obdII signal show actual boost or what it thinks its only making?

Guys with this boost gauge and JB tune please chime in.

Not interested in installing a manual gauge on this car.

Alan

I would think it will only show the boost the ECU thinks it's making, which would be lower than actual boost by the amount the piggyback is adding.

[Alan l.]

You are right. Terry just replied on another thread that the boost reading from the obdII port won't be accurate with the JB so it is pointless for me to get it.

[alextremo]

Originally Posted by Alan l.

You are right. Terry just replied on another thread that the boost reading from the obdII port won't be accurate with the JB so it is pointless for me to get it.

I don't know if I would buy it without an accurate boost reading either, but it does have some other cool functions that should still work for you - EGT, IAT, timing, coolant temp, battery voltage, road speed, RPM, shift light, 0-60 timer...

[scott135i]

Originally Posted by Alan l.

You are right. Terry just replied on another thread that the boost reading from the obdII port won't be accurate with the JB so it is pointless for me to get it.

+1... same for e9x JB platform. You need to tap physical boost, but not sure where that is on N63/N63Tu.

[badblack550xi]

another member was able to read JB boost from this gauge he thought he wouldn't be able to.

[scott135i]

Originally Posted by badblack550xi

another member was able to read JB boost from this gauge he thought he wouldn't be able to.

Oh wait - that makes sense.... I think....


On the E9x platform, when running Jb3/Jb4 which taps the ecu directly, you can read boost via OBD.

However, with the JB+ for N54 and Jb Stage 1 for N63, it's intercepting the actual boost sensor so the ECU should see true boost.

Anyone with a BAVTECH cable running the N63 tune can confirm. If I can find mine I'll do so.

[alextremo]

Originally Posted by scott135i

Oh wait - that makes sense.... I think....


On the E9x platform, when running Jb3/Jb4 which taps the ecu directly, you can read boost via OBD.

However, with the JB+ for N54 and Jb Stage 1 for N63, it's intercepting the actual boost sensor so the ECU should see true boost.

Anyone with a BAVTECH cable running the N63 tune can confirm. If I can find mine I'll do so.

I don't think so - the JB intercepts the signal from the OEM sensor, then attenuates it and sends it to the ECU.

These numbers are probably not accurate, but will work for explanation:

Imagine if the MAP sensor sends a range of 0-5V to the ECU representing boost where 3V = 10psi. The tune is reading that value then adjusting it to say 2V so the ECU asks for more boost. Now when the ECU sees 3V, it is actually 14psi but it will think it's only 10psi which will show in the logging/gauges.

[Jmo550]

i just hook my cable to my laptop and log my boost. Thats the only real way to get true value

but ive been trying to install my aem gauge but no source of boost.

[gtron]

Originally Posted by Jmo550

i just hook my cable to my laptop and log my boost. Thats the only real way to get true value

but ive been trying to install my aem gauge but no source of boost.

do you do that with e-sys?

i haven't looked at it since i coded my car and i've been thinking about how you do that lately.

[alextremo]

Originally Posted by Jmo550

i just hook my cable to my laptop and log my boost. Thats the only real way to get true value

but ive been trying to install my aem gauge but no source of boost.

You mean your JB cable, correct?

You need one of these for your AEM gauge: http://www.dinancars.com/products/5-...apter-Kit.aspx

[dmetuning]

I installed a P3 gauge the other day in my car. It was super easy and took me less than 5minutes. At the time, I had the BMS tune installed which showed I was boosting 12.5psi. When I removed the BMS tune, I was boosting 10.2PSI. BMS adds 2.25psi so if the gauge is setup to round up,which mine is, it works perfectly.

[Alan l.]

Strange.... because Terry on his own forum keeps saying that boost reading won't be accurate with this gauge and the JB on the N63......

Alan

[dmetuning]

Originally Posted by Alan l.

Strange.... because Terry on his own forum keeps saying that boost reading won't be accurate with this gauge and the JB on the N63......

Alan

When I installed the P3 gauge, it was only reading 3PSI. I couldn't figure out why so I emailed P3 and got this answer.

"The gauge defaults with sensor locations for a n55 engine car. Please enter config and change to n63 . The n63 map sensor only reads to 3 psi... So the gauge had to read the charge pipe sensor as well."

I wonder if reading the charge pipe sensor as well as the map sensor has something to do with it on the N63 engine?

[berkel]

Interesting. When I plugged my ScanGauge II into my 550ix, I only saw ~17 PSI MAX for MAP absolute pressure, but this includes atmospheric, so I would need to back that out and get about 3 PSI net. I was hoping that wasn't right, lol. I wanted to get a P3 gauge, but wanted to make sure it would work correctly, so I emailed the P3 guys and they assured me it would work and said didn't rely on the MAP sensor alone.

In the Bavarian Tech software, you log the atmospheric pressure and the Intake charge pressure 1 and 2 for boost in each manifold. The atmospheric pressure changes slightly, but not as much as the MAP sensor readings I would see when watching my ScanGague II. You have to calc the boost by subtracting the atmospheric pressure from the charge pressure and multiplying by a constant (values are in hPA). Strangely, I don't recall seeing the MAP absolute pressure reading as an option to log in the Bavarian Tech software.

Anyway, if the JB tune modifies the intake charge pressure readings, it does seem like it wouldn't work (since the calc would be wrong). If JB changes the MAP sensor reading, the P3 gauge could calc correctly since the MAP absolute pressure isn't part of the eqn to calc boost. However, it is also strange that Terry himself said the P3 gauge wouldn't work?