boost levels to high for stock tune?

[kpr478]

I i figured is final time to post on here after failing to figure out why my boost levels are so high. i got a stock 2010 a5 quattro with 6spd manual and according to my p3 gauge i see 20psi at low rpm and slowly tapers down. for what i have read stock i should be seeing 10-12psi and stage I 16-18 so why am i seeing 20? i just want to make sure every that everything is fine because i am about to go stageII soon and don't want to run into problems because of this. could it be that the p3 gauge can not read boost correctly?


in this video i do a 4th gear pull all with the gauge set to boost (psi) at low end it at 20 and starts tapering down and at redline it get to abut 5 i believe.


here i didnt 2nd and 3rd gear pull and same results 20psi low rpm and tapers down 5psi at redline


here doing normal drive at 3/4 throttle from 2nd-6th gear and the lowest i seen is 15psi?

at first i thought that the car might have stage I but it is limited to 130mph and from what i know any tune will unlock the limiter so i figured it is stock. does anyone has any ideas to why this is happening? and do i have anything to worry about?

[bakedziti]

Is your P3 plugged into the OBDII or do you have an analog sensor? The OBDII will show requested levels.

[kpr478]

it plugged into the OBDII port. but why does it show these level?

[bakedziti]

It appears that your car came with a tune, but again, these are requested values. Did you purchase your car from a private or dealer sale? Sounds like you can begin the round robin search of figuring out your tune company. APR; GIAC; Unitronic...I'd start calling.

[kpr478]

is it really possible to have a tune and still have the 130mph speed limiter?

[A4B8C16D32]

Does the car have any hardware upgrades? Intake and/or downpipe/exhaust with increase the boost. I'm running 15-17 psi on stock tune with a hfc and non-res downpipe. I'm also putting on a magnaflow catback this weekend and expect it to go up a little more again

[A4x]

Does the car have any hardware upgrades? Intake and/or downpipe/exhaust with increase the boost. I'm running 15-17 psi on stock tune with a hfc and non-res downpipe. I'm also putting on a magnaflow catback this weekend and expect it to go up a little more again

Why would the boost go up with a HFC and/or exhaust? I'm pretty sure the ECU is programmed to request a boost level based on many parameters. I dont think the ECU will request more boost with thise modifications. I think only a software flash will make the ECU request more boost. Please correct me if I'm wrong. I think HFC/exhaust will only allow you to reach the requested boost level faster.

[A4B8C16D32]

Why would the boost go up with a HFC and/or exhaust? I'm pretty sure the ECU is programmed to request a boost level based on many parameters. I dont think the ECU will request more boost with thise modifications. I think only a software flash will make the ECU request more boost. Please correct me if I'm wrong. I think HFC/exhaust will only allow you to reach the requested boost level faster.

I had originally thought the same as you, but checkout the answers I got in this thread.

http://www.audizine.com/forum/showth...une?p=11849797

[seangrimes590]

P3 gauge has 4/5 different options for boost, 3 different options for car. Without having the analog boost sensor with boost tap don't count on the readings for anything. Let me give you an example, on the digital output (i.e. OBDII) boost.f would show 34 psi on k04, boost.d would show 28, and finally plugging in the analog sensor gives me a peak of 25.6 - 26.2 depending on gear, temperature, starting rpm. If you're only getting the OBDII reading I wouldn't worry about anything.

[kpr478]

I have no hardware mods. Just a drop in air filter and deleted intercooler sound box. Stock intake pipe, stock intercooler and pipes and stock exhaust. So unless I get a analog boost sensor with boost tap I should worry about it? So does this mean all the other reading will be off? Mainly interested in afr, iat, coolent temp and egt.

[ToddBrunswick]

In the second video, you seem to peak at around 17.8 psi. I think you're mistaking the vacuum (-20.7 inHg) when you switch gears as positive boost.

[seangrimes590]

You have to consider where the values are coming from to determine whether or not they're accurate. You're counting on a lot of interpreted values, like EGT which uses the O2 sensors to estimate the temp. The car doesn't have a 'real' EGT probe so you can't expect absolute accuracy (if I'm wrong then I find my 1950 degree f EGT at the end of a 4th gear pull to be concerning). IAT should be accurate since there is a real temperature sensor, same with RPM, speed, battery volts, timing angle, coolant. EGT, boost, and 0-60 are questionable because they involve computer interpretation instead of getting real readings from sensors designed to sense what you're looking for. Just a limitation of the technology.

EDIT: Not sure where you saw AFR on the P3 gauge, it doesn't exist on mine; perhaps you got a newer model?