[urq] Detonation, Rear Parking Brakes

[fdekat]

> Message: 8
> Date: Sun, 28 Mar 2004 21:23:04 EST
> From: JagerBond at aol.com
> Subject: Re: [urq] 81 WR UrQ Head gasket removal
> To: ur.quattro at verizon.net, ur.quattro at ntlworld.com, urq at audifans.com
> Message-ID: <11f.2c8cb6c0.2d98e288 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
> "
> That type of head gasket failure is caused by detonation, and detonation is

> caused by overly advanced timing, or too lean mixture, or too much boost,
> or  the intake air is too hot. hmm does your URQ have a heat shield between
> the turbo hot housing and the intake housing?
> "
> 
> Mike or James?   I think mine may have been running lean.
> 
> Mike

I've heard that the standard urq ignition timing map should run OK with
regular gas. So.. on the weekend I tried a tank of 'midgrade'. Surprisingly
enough, I heard 'pinging'. I'm thinking that this is not good..
And, as I had to install new hose to the boost gauge to get it to even move,
I started to think about the shape of the hose going to the ecu. I pulled the
glove box apart, and pulled in some new hose. The old hose had the liqyuid
trap just before the ECU. This little filter had so many cracks in it, no
boost or vaccum would ever be seen by the ECU! ECU Never saw boost, so never
backed off the timing. 

I put a big loop in the replacement hose (instead of the liquid trap), and
hooked it all up.

Wow! 
Idle went from 2000 down to maybe 1200 (Couldn't adjust it any lower,
before). Drivability seems much better too. Full power just doesn't seem the
same any more though. However, I realize that it's not going to hole a piston
now either, so I shouldn't complain..!!

As an aside, to the 'rear parking brakes are seized' question:
Cannot 4000q rear calipers and cables be substituted, from  a more 'sane
cost' and parts availabilty standpoint? (But no functional 'upgrade', right?)

Regards,

  -Frank de Kat-