So I've been trying to find out what's the deal with the boost.

Can anyone here with a TTS/TT try their car out in Sport/Sport plus/comfort and let me know what they get for max pressure?

I've been getting 1.0bar(15psi) in Sport/comfort, and when I put it in sport plus, i can see the bar increase, however the boost rarely passes 1.0bar, maybe once for like half a second it hits 1.1bar and goes back to 1.0

Same thing with a friend's 991 turbo. but it feels as if he gets 1.1 more often than I do and sometimes 1.2

Anyone else experiences the same thing? Is that normal?

Looked around in search for threads about this and found none.

Hamad

 

Interesting subject. I have just noticed that my boost drops off at approximately 6000 rpm until it shift at 7200 rpm. My gauge gets fully pegged and shows 17 psi under full throttle, and then drops off to 14 psi at 6500 rpm and pops back up to 17psi after the shift. What intersting is that I'm running a tune that increases boost substantially.

I'd also like to know what others are seeing.

 

In my Panamera, the Turbos do the same, the varying boost if I understood correctly is due to the variable geometry turbines. I cannot, however, comment on what values you should see.

 

After testing it again today, it drops off to 13 psi at 6000 rpm and stays at 13 psi to 14 psi there after. I'm baffled!!!

I'd love to know if anyone else is seeing this. I don't know if it always did this and I just never noticed, or if something not running right. I'm measuring this using the factory in dash boost gauge.

Any other 991 TTS owners have some feedback.

 

i hooked up a mechanical gauge ran it through inside the car and it red 19-20 psi. the oem gauge only red 17 psi 99% of the time. the cae held 17 psi all the way to redline. giac tuned headers n xhaust.

 

After testing mine a couple times, from 60+ I floor it, it reaches 1.2 bar initially, then drops to 1.0~1.1 and holds that til forever.

Friend's 991TT does the same thing. And another friend's 991tt also the same thing.

I wonder if you can do something about it to hold 1.2 all the way?

My car has FVD software module and full exhaust.

Edit: When I hit Sport Plus the built-in boost bar increases. in comfort/normal I believe the boost is limited to 1.0

 

That's so interesting. Are you running GIAC Stage 2, and does it change from Sport to Sport plus?


Crazy thing is that I always thought I pegged it to 17psi and kept it there before the Stage 2 upgrade. Yet the car feels faster with the Stage 2.


Confused

 

im still on stage will be geeting the stage 2 on wednesday. i will update any differences.

 

CPIGUY,

How quick does the car feel with GIAC stage 2? Have you raced against a 650s? or a 12c?

Wondering how fast it is cause I've raced a 650s and it was pretty much dead even til 220+ then he start slowly pulling, by the time we hit 250 his rear tyre was next to my front bumper. (Note: it was a 70km/h start.)

And regarding the boost thing, I'm still wondering if the car loses power when it drops from 1.2 to 1.0 or is that a normal thing due to the geometry of the turbines x_x confused aswell

-Hamad

 

I have not raced a McLaren, but at the last 1/2 mile airfield event I beat one of the fastest 997-2's out there, who I know for a fact beat a 12c that day. I never lost a race the entire day. That was when I was running stage 1.


Stage 2 definitely feels faster than stage 1, but I don't remember my boost dropping off after 6000 rpm. I could have sworn it stayed pegged at the 17 psi through the entire rpm range. This make perfect sense cause a turbo s makes 19.6 psi stock and with the tune I should be pushing well over 20 psi. more like 23 or 24 psi.


I'm trying to figure this our before Saturday when I have another 1/3 race day.

 

ok got the updated today plus a few minor ecu tweaks. the boost respond is quicker and feel smoother but it idles a little rough. the rpm dropped like it was going to die and then smooth again.

 

What's the factory boost gauge reading when you get to 6000 rpm? I'm trying to determine if my car is malfunctioning. I'm being told that the factory gauge may be getting confused by the Stage 2 tunes modifications.

Will you be at the Shift3ector races on Saturday? I'd love to race you to see how our cars compare.

 

CPI takes some videos for us to enjoy of the races.

 

no i wont be there, the car held 17 psi all the way through. u can pm me and we can play around b4 or after s s3ctor just for comparison.

 

I plan to 😀