991.1 Turbo S boost pressure only 0.6 bar at WOT
 

Hi All. I recently purchased a 991.1 Turbo S (a late 2013 model) Hi All. I recently purchased a 991.1 Turbo S (a late 2013 model with only 11,000 miles on the clock).

I wanted to ask what it the boost pressure when WOT? 9 times out of 10 I only see a maximum of 0.6 bar of boost when WOT in all three modes - normal, sport and sport + modes. That's 0.6 bar of boost when WOT throughout the rev range (most of the pulls I have done are from 3500RPM all the way to the red line in 3rd, 4th and 5th gears). Sometimes my turbo boost reading is displayed in orange which indicates the over boost function is activated but the boost doesn't surpass 0.5 bar of boost for the whole duration that I am WOT whilst it is orange.

The very few times that I have seen 1.0-1.2 bar of boost is from low speeds the majority of the time when in 1st and 2nd gear. But 9 times out of 10 I don't get past 0.6 bar of boost and the car feels much slower than when it slingshots forward at 1-1.2 bar. I have probably launched the car 30 times in a couple of weeks. I have a Dragy device and the best 62-124MPH (100-200KMH) time I can get is only 8.5 seconds.

As I understand I should experience between 0.9-1.0 bar of boost throughout the rev range.

Do I have a turbo boost issue? Any ideas what it could be?

Thank you in advance.

Hello,

You have a big boost leak.

I suggest to check all intercooler hose clamps, ypipe clams, throttlebody clamps first.

If they are all good, you can look for Diverter valves to see if they have leak or their vacuum source is on.

Thank you Emre, I will book my car into my local Porsche dealer and tell them that I have a boost leak. I assume they'll be able to do a full boost test using their computer so hopefully it should flag up any boost leaks?

Thank you Sam 😉

They cant exactly see where its coming from just by looking at pc.

However it may be VTG actuator fault. Sometimes VTG rod pops out and cause low boost problem.

Since its a big loss in boost, it should be something obvious, like a VTG actuator rod, or a clamp loose or broken.

had that happen to me, it was a busted actuator. replaced, reprogrammed, back in business .

Just an update - good news - just got a call from my local OPC to say that they have completed their diagnostics and have ordered a replacement turbo actuator which should resolve my boost issue 😁. Thank you for all of your help.

Hi, I seem to have the same issue on my 14 Turbo S. I have also noticed that if driving normally and lift off at around 2000-3000rpm, the car makes the noise similar to a dump valve dumping pressure out. This noise issue started at the same time as the boost pressure going up to 0.5bar.

thanks

Most likely you popped the intake coupler between the throttle body and the y pipe. I had this exact issue last month.

You can remove the fan cover, just pop it out, then remove the plastic intake tube for the airbox and you will see the coupler. If you place your hand on it shake it, push it towards the throttle body. You will see this is off the y pipe. Unscrew the clamp place the couple correctly and re tighten... boost should go back to normal.

I will be upgrading to the 991.2 version. It is redesigned to hold better supposedly . The part name is distributor sleeve, part #991-110-677-71

Initially my dealer thought it was the Y pipe but they checked and it wasn’t. They even replaced it but still the same.

Also noticed that after starting engine and warming up, for just the first revs up to redline there is decent power but boost only 0.5-0.6 bar. From next revs car doesn’t show any boost on the gauge and feels much slower (without turbos).

thanks

Something like this happened to me recently. I would get full boost for a bit but it would drop immediately down to like 2psi and not go up. I ended changing the OEM plenum to a DO88 plenum and replaced the rubber boot that attaches to the throttle body and y-pipe. This solved my issue. Also, while I was doing this, cleaned the throttle body and with the iCarsoft device, I reseted the throttle body position.