Boost Problem

[art@rmeuropean]

I am looking at a 2002 996tt with 29K miles. I drove it today and it seems like it has a hard time reaching max boost. As soon as it starts boosting you hear a hissing sound out of the engine and the highest boost I've seen was 0.6bar. Most of the time in 2nd gear it won't get past 0.4. I really like the condition of the car but I don't feel like spending any extra money fixing it because the price of the car is higher than median. Is it a simple boost leak or are there any other more expensive issues that can cause this condition? Thanks for your help.

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[wross996TT]

probably a simple boost leak or leaking DVs in either case not tough.

[smdubovsky]

AFAIK, 0.6 is stock boost. An X50 has 0.8 stock. Should build pretty quick though.

[art@rmeuropean]

I took the car to the dealer this morning for a PPI and they found two leaks near the driver's side intercooler. They replaced two $9.00 o-rings and apparently the car reaches max boosts just fine now. I will drive it tomorrow and hopefully it feels faster. On a first test drive it felt way slower than other 911 turbos I've driven.

[stv951]

i am also facing some boost issues on my newly acquired 996 TT S (hence X50) car wont pass 0,6 bar (might see 0.7, but very rarely)
What are those O rings that o=you found to be leaky ? Have you got any part Nos ?

Just replaced the DVs with new bosch oem ones, but no cure. My car is absolutely immaculate with 13k klms covered from new. Thats 8k miles
Any other ideas ?

[SamboTT]

Art, glad to hear it...fun cars

Stv, the o-rings are not as common. You will want to do a pressure test. That is most likely how the dealer found the problem on the other car. There can be multiple small leaks and there are also many check valves on the pressure side that can cause issues. All pretty easy as Wross said considering.

Sam

[art@rmeuropean]

They were actually the Y pipe o-rings. Part number 996-106-801-06. There are a million place where you can have a leak so do a pressure test before buying any parts.

[stv951]

Thanks guys. Really helpful.
I guess that in order to check for leaks, there is a short of pump that causes vacuum on the system, right ?
anyone knows where the pressure tester is connected ?

[steve harris]

please think about getting rid of the bosh dvs(OEM)

[Prche951]

Originally Posted by smdubovsky

AFAIK, 0.6 is stock boost. An X50 has 0.8 stock. Should build pretty quick though.

my car was .8-.9 stock and it is not an X50, and it was not flashed. It ran hard stock.

[FAST FWD]

There's a nice thread on boost leak testing:

DIY pressure/boost leak test rig w/pics

I just had this done. There was a big leak at the upper hose connection to the intercooler on the passenger side. My indy uses a smoke generator in conjunction with the pressure. See the photos below. The one from farther out helps you see where you are.

There are o-rings inside the connectors on the ends of the hoses. That's probably what they replaced. A lot cheaper than the red silicone hoses I bought, but these new ones look cool.

Jon

[04TTCab]

I am totally confused now. On my bone stock 04 tt I hit .6 quite often, and it does get up there real quick. I have hit .7 and .8 before, but that was only a couple times, .6 is actually just about every time I am in the car!

I thought I may have had a leak till I read .6 is the stock setting, but with Prche951's post I am thinking leak again.

What does a shop usually charge to do a pressure test? art@rmeuropean, was your test done at the dealer? What did they charge?

[Prche951]

I just looked it up in a book I have on the 911's and the 996TT runs at 0.85 bar. Hence why I saw .8 to .9.

[stv951]

Originally Posted by FAST FWD

There's a nice thread on boost leak testing:

DIY pressure/boost leak test rig w/pics

I just had this done. There was a big leak at the upper hose connection to the intercooler on the passenger side. My indy uses a smoke generator in conjunction with the pressure. See the photos below. The one from farther out helps you see where you are.

There are o-rings inside the connectors on the ends of the hoses. That's probably what they replaced. A lot cheaper than the red silicone hoses I bought, but these new ones look cool.

Jon

hmmmm...... thats pretty interesting. Thanx, ill give this a try for sure

[FAST FWD]

Originally Posted by 04TTCab

I am totally confused now. On my bone stock 04 tt I hit .6 quite often, and it does get up there real quick. I have hit .7 and .8 before, but that was only a couple times, .6 is actually just about every time I am in the car!

I thought I may have had a leak till I read .6 is the stock setting, but with Prche951's post I am thinking leak again.

What does a shop usually charge to do a pressure test? art@rmeuropean, was your test done at the dealer? What did they charge?

I thought that the stock spec was 0.7 bar. I dunno. Mine has an Upsolute flash, that maxes out at 1.0 bar.

My indy charges by the hour. I would estimate that if all you did was remove the airbox and hook it up to a pressure line, it would be an hour, or at most two. If there is a leak, then the cost of fixing it would depend a lot on where it is. Some of these junctions are easy to get to, others more difficult.

My car's bumper and fender liners were already off because I was already in for new coil packs and plugs.

Jon