Recently installed a Podi boost gauge, after running the car and turning it over a few times, it was reading vacuum 20inHg at idle (probably needed to calibrate...initial reading of 6inHg threw me through a loop for a moment) - from poking around with the forum search I've gathered this is normal vacuum.

Over the past few days, during spirited driving the gauge has shown a consistent 21psi with taper dropping 4-6 psi, which is reportedly stock behavior

I have my boost pressure warning set to flash at 23 psi (thinking the car being stock - minus the ETS intake that uses stock MAF housing - I would not yet be seeing it change from white to red) but after giving accelerating a little more aggressively than usual, my gauge flashed red. I checked peak recall, 24 psi. Might be important to note I'm pretty sure this happened shifting into middle revs in 4th gear.

Last night I went for a cruise with my roommate, I decided to merge back onto the highway again and to actually go WOT and see what the gauge would read out, once again my gauge flashed red. I really wasn't sure if I was seeing things properly at the time, I caught was my boost tapering down to and holding to 24 psi, I made my way back in town and checked peak recall, 27psi.

I've read depending on where you're situated people have seen stock boost anywhere between 19 and 24psi... so I could understand the possibly of a higher stock boost reading but... peak 27psi wut?

Can anyone enlighten me as to why this is happening? I don't think the gauge is inaccurate, granted its reading idle vacuum properly and has been reading what most people have reported as stock boost pressures... I'm not sure if the ETS intake would have that large of an affect on things.. I don't have a stumbling idle or strange leaky sounds coming from the engine bay.

I'm new(er) to FI so please excuse my asking but, would a boost leak cause this much of a difference?

 

Are you on a stock tune?

 

Two responses ...

boost leaks don't usually cause higher-than-normal boost

if you know the gauge is inaccurate at idle, why are you trusting it for boost?

 

That is pretty norm in 4th gear pulls. I am tuned to 23psi and my gauge reads 3-4 psi higher then the real psi. In 4th I hit 26-29 psi at fist wot then it will go back down to 25psi and hold till redline. In 3rd down at wot it goes to 25psi then holds. Seems like only 4th gear wot jumps a little but your gauge might be off a little also when you tune have them check to see how off your gauge is that way you have a good idea where you are at.

 

Yessir

Good to know.

And the gauge isn't reading inaccurately at idle anymore, it was only the first time I ran the car after installing the gauge that it was showing 6inHg at idle, since then 20inHg all the time.

I figure because the gauge uses an electronic boost sending unit, it may have needed to calibrate it's first time around. The boost sending unit can also be calibrated for altitude.. < this I'm not overly worried about.

Do you mean that would be normal for your 23psi tune haha or normal behavior for fourth gear overall?

My friend said the only thing he could come up with was the peak might have had something to do with ambient air temps, when I peaked 27psi tapered to 24psi I was out and about around 2 AM (colder, denser air) .

I gave it a quick run last night on the way home, 1st gear hit around 5psi, second gear hit around 15 psi, I paid specific attention to 3rd gear which hit 20 psi and started tapering... I'll pay more attention to fourth.

Considering grabbing an AP to compare numbers.

Thanks for the help guys.

 

As this thread continues, please use tech terms accurately.

Boost creep is caused by an inefficient wastegate. For example, when the O2-sensor housing doesn't flow well, even when the wastegate opens, boost continues to rise or spike. (nb. if you autocrossed a 2G DSM ten to fifteen years ago, boost creep was your best friend.) The key is that boost creep can't be fixed by playing with the control of the wastegate; the wastegate is open, but just isn't dumping enough exhaust to keep the boost down. The solutions for creep are porting the wastegate hole and/or replacing the O2-sensor housing, preferably with a divorced-pipe version.

Over-boost (or any term like it) can either be a general term for "I gots too much of da boost and worried my car die soon" or it can mean a problem with the control of the wastegate in particular. There are tons of solutions for this.