Oil inside tbb, cause for concern?

[Mika]

Hello all!

The other day I experienced a sudden loss of power accompanied by a whistling noise under load...
Tonight checked the throttle body boot and found a 15 mm tear underneath the clamp not visible from the outside.

The thing that got me worried was a slight film of oil inside the right side of the boot and intercooler pipe. The left side was totally clean.
A quick search through Audiworld archives suggested it being either a sign of a turbo failure or just normal; oil coming from crankcase ventilation system...

Any of you experienced this? Should I be worried and have the turbos checked? Is it possible to service or reseal turbos or does it always mean a new unit?

P.S. The oil consumption is virtually nil, no puff of smoke ever either. Abt 310 hp/ 505 nm chip, circa 40000 miles...


Thanks,

Mika

[Dippy]

Mika,

A 'film' of oil is nothing to worry about - as you mention, the air system is partly connected to the crankcase.

Work can be done on the turbos, but that doesn't save much money really. The problem is that to access the turbos the engine needs to be removed. Also since the turbos must be balanced, any work on one would necessitate working on the other. Besides, if you're like me, then if you had to have work done on the turbos then you'd be best off biting the bullet and installing RS4 ones.

For now just keep monitoring for smoke from the exhaust at start-up and listen to any whistling from the turbos. If you don't get either then you're probably OK.

That TBB is prone to failure, especially on chipped cars. You could keep a spare, but as you've discovered, it's not always possible to see a tear, and the tear won't always result in an obvious power loss. However any leak can cause stress to the turbos.

I cannot recommend the APR bipipe enough. Remember that your chipped S4 is almost as stressed as a stock RS4. And Audi decided to replace the TBB with a metal unit on the RS4...

[Mika]

Dippy,

Thanks for your reply...phew that was a relief![img]images/graemlins/1syellow1.gif[/img]
I´ll certainly consider the APR bipipe.
What is the RS4 metal tbb like, can it be fitted to a S4?
What kind of performance gains are expected from fitting either of these?

Mika

[Dippy]

The RS4 unit is actually 3-piece whereas the APR one is a single cast aluminium unit. I doubt there would be much difference between the two except for price (the RS4 one is undoubtedly more expensive). I don't know if the RS4 unit would fit, but I'd expect it to. At least the APR bipipe is guaranteed to fit the S4.

The purpose of the bipipe is reliability, however I can imagine slight performance gains because:
1) The recirculation ports are enlarged improving airflow through the DVs.
2) Compared to the stock setup, the internal air path is much smoother, and more focussed towards the throttle itself. Thus again airflow should be improved.
3) Since the bipipe is inflexible (whereas the TBB can really balloon under full boost), the volume does not change and thus throttle response should be better.

However all this is theoretical and I would be lying if I said that I noticed any of this after fitting!

[Joules]

Mika,

If you are changing your stock TBB hose, it would be worth fitting the revised clamp which does not bite into the rubber neck as much.

[Golich]

Dippy and I have discussed this TTB before. I'm running a AMD chipped S4 with a stock TTB and like you had the boot burst BEFORE the chip. After the chip one of the right hand intercooler pipes came off (looking into the engine bay) as the jubilee clip wasn't tight enough.

Like you it too had oil in it while the other was dry. But that was 8K ago and no probs on a 54K car.

A cheaper alternative to APR pipe is a forge TTB at £50.

So far though I've not had any more problems with my stock TTB and I carry a spare around with me at £7 I'm happy with that and I check for a possible tell tail oil residue under the TTB from time to time. But dippy is right, it is known for folks not to notice the burst and you may well run around over stressing those KK03s.

I can't remember how much the APR pipe is £250 comes to mind - Dippy?

[Dippy]

I think it might be £280 - although I bought mine at GTI International 2002 for £200 [img]images/graemlins/grin.gif[/img]

When AmD chipped my car I asked for the Samco TBB which must be similar to the Forge one. Scott said that they had a problem reported where the boost sensor was pushed out by the extra pressure. So they gave me the latest Audi OEM TBB which is thicker (although it looked identical to my old one), plus the AmD 'fix'. Trouble is the AmD fix was just a tie-wrap!

So that's why I got the bipipe. I will readily accept that I am a cautious person regarding engineering reliability, however when it comes to peace of mind the bipipe certainly gives it!

[Golich]

Dippy your right, it's the Samco hose I meant to say. Forge motorsports sell them for approx £50.