Turbo overboost?

Drew

Hi all. I've just found this forum and jumped on because of an issue I've got with my 2008 XC90 R design diesel auto. It's taken to blowing the intercooler pipe off the turbo, the plastic pipe that runs under the sump is missing its mounting lugs so I zip tied it up to give it some stability but it's blown the pipe off again.

The car has always been a bit laggy when I take off, but the turbo kicks in at about 2000rpm and it nearly chirps the tyres. We've got a spare parts car, 2010 model with the 6 speed manual transmission, it's also a bit laggy off the line and leans into it when the engine speed rises. Because they're the only two xc90 diesels I've driven I don't know if this is normal. I haven't looked at any of the turbo operating systems as yet.

Forg

Is it laggy for a 2008 diesel XC90, or is it laggy compared to a turbo petrol vehicle?

If this had been my car (which is neither diesel nor an XC90 so I have zero clue really 🙂), I'd have suspected maybe the ECU-operated boost-control valve was misbehaving. I don't even know whether a 2008 diesel XC90 HAS a boost-control valve, but if so, this would mean maybe the wastegate isn't opening when the ECU's boost-level is met.
Or maybe even the wastegate is stuck shut - might be worth checking whether it's stuck?

Drew

I haven't looked into it too deeply yet. On other forums there has been quite a bit said about turbo vanes getting carboned up or the actuating mechanism sticking, so I will have to investigate further.

timbo

Drew usually the orange rubber seals swell and split, causing the boost pressure to blow them off.

You can replace them but most people just replace the entire pipe with a factory replacement or berry motor group keep an alloy upgrade I think.

If you've driven it around with the pipe off it also fills the particle filter up quite quickly so might need a burnoff