Pry

Should I get the full boost faster than this?
My car is a stock 993 Turbo.
Any ideas what might be the problem?

Quadcammer

yes, stock 993tt should see .8 bar at like 3800rpm.

any vacuum leaks? intercooler hoses seated well? turbos in good shape?

any obdII codes?

Pry

The intercooler hoses are tightened well at least at the intercooler end.
Haven't read the obdII codes since last service. Can an ordinary service shop read all the codes or should I take it to a Porsche dealer?
If it's the limp home mode shouldn't it limit the boost to 0.5 bar?
Sometimes when I'm off throttle or just cruise at 30 mph I see 0.2 bar at the gauge when I believe I shouldn't have any boost. Weird.

Felix

That suggests the boost sensor has seen better days - either try a new one or a separate boost gauge.

Pry

Thank you.
So I'd probably need to get one of these:
http://www.pelicanparts.com/More_Inf...0%281996-97%29

rcg412

Probably boost sensor. I had mine replaced, because it always read 0.8, and 0.2 idle. Got a new one and now usually maxes at 0.7 sometimes 0.8. So I had shop test it with smoke test for leaks (none) and manual gauge, hit 0.8 no problem. Manual gauge only true way to verify. Anyway, just don't have a lot of faith in the sensor

Stewart

You may have one or both actuators failing - these are what are effectively physically controlling the boost produced by the turbos.

DM993tt

...possible worn out BOV's as something else to check.

Felix

Yes, that's the one.

Seconded - if your boost gauge reads something other than 0.0 at idle or under engine braking (or with the engine off!) either ignore the boost gauge or get a new sensor.

Pry

Thanks guys for the help!
The gauge reads some times 0.2 bar at idle also.
So I believe the sensor would be a good place to start?
The sensor is probably broken anyway even though there could be something else wrong too?

Pry

I changed the pressure sending unit. It fixed the issue with the gauge reading boost on idle but I'm still struggling to see full boost just like in the video. I have new gasket between intercooler and throttle body so it shouldn't be leaking there.
I have no OBD codes.
Would you recommend to check the actuators or BOV's next or do you have any other ideas?
How do I know if those are working correctly or not? Do I have to get them replaced or is there any other way to tell?
Is it usual for the boost hoses to leak at the turbo end?

OverBoosted28

You never mentioned if you're actually getting full boost and it's just not showing on gauge. Do you feel the boost as it should be or are you not actually getting all of it? There are about a dozen or so places with small vacuum connections. Some are small plastic rigid lines with rubber attachments at various places (FPR, blow off valves ect...) check all of these. Look at my previous post "Hoses" earlier this week. These might be failing. It's most likely vacuum leaking somewhere. Good luck

Felix

What gear are you using to check max boost? I ask because I think the engine will struggle to make max boost in 1st or 2nd and possibly even 3rd because the revs climb too fast and the turbos don't have enough to "push" against to generate full boost.

Pry

I only have the factory digital gauge to check the boost. I honestly don't remember how it should feel when the car is working correctly. It pulls quite well at 0.5 bar also. There are only 5 TT's in the country and most of them are tuned so testing a friends car isn't an option either.

I've done 2nd, 3rd, 4th and 5th gear pulls and it usually gets up to 0.5 bar but then it really struggles to get more. Today I did 3rd gear pull and first the boost got up to 0.7 bar and then dropped to 0.6.
It's really rare to see 0.8 bar on the factory gauge.

Felix

The factory boost graph hits 0.8 bar at just below 3000 rpm and stays above 0.8 until about 4700 rpm.