[urq] Fw: turbo question

[SpotatAshleys]

Back in early December I asked the question below on behalf of a friend of
mine and received some helpful replies but it was clear that I had not
originally given enough information. I have learned a little more in as much
as th turbos in question were a KKK of indeterminate type/model (possibly a
hybrid) and three Garrett GT34s. The motor runs 2.2 bar. The wastegate
functions perfectly, the oil is changed after every meeting (hill
climbs/sprints). All turbos have been oil fed/cooled - not water cooled.
After the last failure, the oil which was 0 miles old came out looking like
cold tea. The engine has been taken down once and found to be undamaged and
is currently undergoing another exploratory tear-down and rebuild to see if
anything can be identified as the culprit. The management is a MOTEC set up
and nothing in the datalogging suggests a problem here.
As before, any suggestions as to the possible cause of the turbo failures
will be gratefully recived and passed on.

Hope you all had a good Christmas and have an equally Happy New Year

All the best

Keith

'87 WR


----- Original Message -----
From: "SpotatAshleys" <spotatashleys at hotmail.com>
To: <urq at audifans.com>
Sent: Tuesday, December 11, 2007 8:14 PM
Subject: [urq] turbo question


> Evening chaps
> A friend of mine who has no access to internet has asked me for help. He
has a sport quattro replica (lucky chap) but has recently suffered a series
of kkk turbo failures (not so lucky). In all instances all damage has been
down stream of the engine i.e. no damage to the engine. What happens is the
exhaust side explodes (literally) throwing bits of metal everywhere.
> The engine is a finely tuned 20v, running modest boost but dyno'd at about
500bhp - prior to all this. The failures have come after virtually no miles.
In one case, about 20 yards off the start line after last rebuild.
> The oil supply to the turbo has been checked and given the all clear. No
bits in the oil. Datalogging shows no curious changes in mixture (leanness).
The things just explode. All bits go down stream. Engine strips revealed no
damage - I think I said that already.
> To me it seems like exhaust isn't flowing enough when at WOT causing
pressure build up, heat build up and bang. Doesn't seem possible though.
Prior to each failure, it runs smooth, no smoke, no noises, no water temp or
oil temp rises. Weird.
> Any ideas what could be causing this? His bank manager is starting to ask
questions....
> All ideas gratefully received.
>
> Cheers
>
> Keith
>
> '87 WR
> _______________________________________________
> Audifans urq mailing list
> Send posts to: mailto:urq at audifans.com
> Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
> UPG2008 planning at: http://autos.groups.yahoo.com/group/urquattro/
>
> You can help keep the audifans site running by shopping at
http://audifans.com/shop/
>