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lack of boost

graemeho

Well-known member
Joined
16 Jan 2012
Messages
423
been investigating a lack of boost on my 997.1 turbo for the last couple of weeks. It's been stubbornly at about 0.7bar, rising to about 0.9bar in sport mode if you give the beans :dont know:

checked for sticky actuator rods, all fine

As it's bank holiday Monday I thought I'd look a bit deeper into it. Removed the rear PU and had a rummage.

Nearside bottom intercooler pipe top jubilee clip was a bit loose, so maybe source boost leak? After looking a bit further into it, the bottom clip and hose on offside virtually fell off in my hand when I give a waggle. The clips on these look a really crap design, although I managed to reclip the hose into position it still has a load of movement when you move it?

video clip below:

https://www.dropbox.com/s/pi47fp4c7z8uh5h/Video 28-05-2018, 13 36 44.mov?dl=0

Also, the internal bit of the fitting is coated in some pink residue (coolant?). Is the anything to be concerned about?

https://www.dropbox.com/s/f0rofrdf4kc7yxs/Photo 28-05-2018, 13 33 51.jpg?dl=0

https://www.dropbox.com/s/f0rofrdf4kc7yxs/Photo 28-05-2018, 13 33 51.jpg?dl=0

:?:


I'm thinking a pair of new hoses are in order. Has anyone upgraded to silicone hoses? if so do these fit on standard intercoolers :?: The ones I've looked at don't seem to have the steel fitting the same as the standard one at the intercooler end :?:
 
The red stuff is rubber grease .. someone has had it appart before and used that .. personely id wipe it all off.

If it was a loose pipe then they tend to blow off completely giveing you no boost on that side ... not checked one for sideways movement .. there is a rubber seal inside the pipe isnt there ?

Have you done a check for any fault codes ?
 
Looks like there is a rubber seal inside the hose dermot. Given the amount of movement I can believe that it's making a decent seal. Would guess the seal is worn.

Thanks for the tip about the grease, will wipe it off


No codes showing
 
As you seem to be mechanically inclined, if I were you I would do a boost leak test. Invest in a mini compressor, it will be worth it. :thumbs:
 
graemeho said:
Looks like there is a rubber seal inside the hose dermot. Given the amount of movement I can believe that it's making a decent seal. Would guess the seal is worn.

Thanks for the tip about the grease, will wipe it off


No codes showing

From recent experience you won't get codes even if the hose has fully separated. Check the air box end as well, I had a boost leak from there even once I'd fixed the more obvious intercooler hose end. I did notice that came with a distinctive noise though, like an extremely loud boy racer waste gate inside the car. I was getting about 0.5

However I'm still not convinced I have full boost now either, maybe 0.8. I did have a misplaced O ring (which should sit at the very end of the metal section of the hose but had slipped up near the rubber part) when pushing hard to get the hose on, which didn't work because the O ring was blocking. I'm wondering if that O ring took some minor damage in the process.
 
If you aren't convinced you are getting full boost, just do a boost leak test. It will identify where your boost is leaking from. Some garages may make it seem like a boost leak test is big task when it isn't. If you have a boost leak, it is unlikely you will get an error code. Your turbos will just have to spin fastter (work harder) to compensate for the leaking pressure which isn't ideal as you can imagine. If the boost leak is large you will just get lower boost pressure shown on your dash but again I doubt you will get an error code.
 
Ishay said:
From recent experience you won't get codes even if the hose has fully separated. Check the air box end as well, I had a boost leak from there even once I'd fixed the more obvious intercooler hose end. I did notice that came with a distinctive noise though, like an extremely loud boy racer waste gate inside the car. I was getting about 0.5

Your right, when my car had a boost leak the other year, there was a very loud turbo noise inside the car, as if there was no air filter connected. You could hear the turbo spinning up. Sounded really good tbh, as normally they are very quiet inside.

With the leak, the car would seem fine for a bit, then suddenly go into a limp mode, restricting boost to 0.4 bar on the dash. Turning ignition on/off would reset it, then after a mile or so it would go back into limp mode.
 
thanks all

I've ordered a pair of new bottom intercooler hoses (and clips) from OPC Sheffield this morning, which came in at a reasonable £123.41 all in

Job for the weekend to swop them over and then box it up and re-test. Given how bad the hoses fit I can't believe that this wouldn't have been the reason for the leaking boost. The 'O' ring inside the steel part of the hose fitting looks very squashed too :?:

will report back
 
Finally got around to installing the new hoses.

The old ones were definitely leaking and past their best. When I compared the o rings on the new hoses these had a pronounced lip on them. If you run your finger across the old ones then it's difficult to feel any ridge against the fitting.
This was clearly why there was play when you waggle the hose


The old hoses also squash easily in comparison. (I did read somewhere that Porsche improved them a few years back)

Anyway, boost is now restored and all is well again !

It's a fairly easy diy so I would recommend checking yours if they are original ones as they could well have degraded like mine had
 
graemeho said:
Finally got around to installing the new hoses.

The old ones were definitely leaking and past their best. When I compared the o rings on the new hoses these had a pronounced lip on them. If you run your finger across the old ones then it's difficult to feel any ridge against the fitting.
This was clearly why there was play when you waggle the hose


The old hoses also squash easily in comparison. (I did read somewhere that Porsche improved them a few years back)

Anyway, boost is now restored and all is well again !

It's a fairly easy diy so I would recommend checking yours if they are original ones as they could well have degraded like mine had
I will be doing this also as the fit at the bottom hose unions is a bit questionable if it's supposed to be a sealed system. Did you use any lube before slipping home?
 
No didn't need to use any lube to install them. They fit on really easily without
 

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