2005 XC90 T6 Executive Project Car.

[bmdubya1198]

Yeah, I'm curious as to how you're getting up to 7 PSI just by revving. Sounds like something is wrong.

[RickHaleParker]

Yeah, I'm curious as to how you're getting up to 7 PSI just by revving. Sounds like something is wrong.

I am wondering if it is raw fuel burning in the Cat. Temperature goes up, gases expand. Basic principle of any explosion. Misfire cylinder X, start-up, does shut off Rear heated oxygen sensor control and Fuel trim.

If it was a clog in the exhaust system I would think it would jump to 7 PSI and stay there.

[bmdubya1198]

I am wondering if it is raw fuel burning in the Cat. Temperature goes up, gases expand. Basic principle of any explosion. Misfire cylinder X, start-up, does shut off Rear heated oxygen sensor control and Fuel trim.

If it was a clog in the exhaust system I would think it would jump to 7 PSI and stay there.

That theory makes sense. It still seems strange to me though, if the cat is clogged, wouldn't it be harder for the turbos to build boost if the exhaust gases are getting backed up? Or maybe I've got it backwards and it's creating the load required to spool the turbos.

[RickHaleParker]

That theory makes sense. It still seems strange to me though, if the cat is clogged, wouldn't it be harder for the turbos to build boost if the exhaust gases are getting backed up? Or maybe I've got it backwards and it's creating the load required to spool the turbos.

A turbo is a windmill. Some of the Kinetic energy of the exhaust flow is transferred to the turbo, that is what spins the turbos. Of course you need enough exhaust flow Kinetic energy to do the work. That is why turbos only spin when you got a Kinetic energy surge such as when you are accelerating.

Clogged exhaust would slow down the flow. Less flow = less exhaust flow Kinetic energy. Less energy to do work.
Not necessarily the Cat at fault, Resonator and Muffler can do it also.

Think of it in terms of energy transfers. A turbo recovers some of the wasted energy going out the exhaust system and transfers the recovered energy back to the engine.

The recovered energy can be used to improve fuel efficiency (LPT). Or produce more torque and power (HPT) .

[Roger_850T]

Anybody know where to source the seals for VPN 30636760?

Following, I'll pipe up if I think I can help!

Not sure if this helps, but here is the 30636760 hose, not necessarily the seal...
https://www.fcpeuro.com/products/volvo- ... o-30636760

Or from Volvo:
https://www.volvopartswebstore.com/prod ... 36760.html

Looking at the parts diagram, I'm not seeing the part you posted a picture of...

Roger

[RickHaleParker]

Looking at the parts diagram, I'm not seeing the part you posted a picture of...

That is what I am finding, $175 for the whole assembly. If nobody can locate replacement seals, I will do one of two things. Build up the seals with RTV or soak the seals in ATP AT-205 Re-Seal to recondition them. Still debating on which course of action.

The seals have no apparent damage.

[Roger_850T]

That is what I am finding, $175 for the whole assembly. If nobody can locate replacement seals, I will do one of two things. Build up the seals with RTV or soak the seals in ATP AT-205 Re-Seal to recondition them. Still debating on which course of action.

The seals have no apparent damage.

Where do the seals go? I'm looking at the diagram, and I don't see anything that looks like the picture you posted. If you can point me at where the seals go, I'll keep digging and see what I can find...

Roger

[Roger_850T]

GR-373062.jpg

Can you point at where it goes in this picture?

Roger

[RickHaleParker]

Where do the seals go?

The red arrows are pointing to the location of the seals. The bulges off the main pipe are just clipped on. I know the diagrams show a different pipe.

Hum, I never checked the bulges for a separate part number ...

[RickHaleParker]

No separate part number for the bulges.

Picture with a bulge unclipped and the seal in place. Looks like resonator chambers or reservoirs.

IMAG0317.jpg