[urq] 20vt ur-q Backfires - Thoughts?

[Martin pajak]

Yes and no.

There are two types of backfires, through the intake and through the
exhaust.
Intake backfires usually mean lean misfire, while exhaust type mean rich or
rich spikes.

HTH
Martin Pajak

http://www.quattro.ca

1983 Audi Ur-quattro (305,000 km) for sale : (
1985 Audi Ur-quattro (210,000 km) Euro spec. import mit 3B ;o)
1971 Porsche 911T (45,000 mi) all original



-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com]On
Behalf Of Rich Letsinger
Sent: 31-Aug-04 13:42
To: urq at audifans.com
Subject: Re: [urq] 20vt ur-q Backfires - Thoughts?


Correct me if I'm wrong, but I believe a backfire is
ignition of gasses in the intake tract or in the
cylinder while the intake valves are open.  It ends up
coming out on the intake side in the engine
comparment.  This is more of a carburetor thing and
would be very bad on a fuel injected engine.

This isn't what you guys are talking about.  You guys
are getting pops or bangs out the exhaust.  This is
just unspent fuel buring in the turbo or cat, which
happens with my 3B too.  The former that is, no cat on
my car. ;)

Rich

--- Brandon Rogers <brogers at terrix.com> wrote:

> My car occasionally has small backfires on hard 1st
> to 2nd gear shifts.  And
> I do have cats.
>
> Glad to hear I'm not alone....
>
> Brandon
> '84 ur 20V
>
> ----- Original Message -----
> From: "Martin pajak" <martin at quattro.ca>
> To: "Michael Hopton" <Michael at siliconoptix.com>;
> <urq at audifans.com>
> Sent: Tuesday, August 31, 2004 8:13 AM
> Subject: RE: [urq] 20vt ur-q Backfires - Thoughts?
>
>
> > Now now... ;)
> >
> > I do get some nice ones once in a while......
> > I've scared few pedestrians waiting at a bus stop
> once... ;)
> >
> > If we had Catalytics this problem would probably
> not be there.
> >
> > How did you like Belgian GP???
> > Sorry I missed it... my Taxi service was not
> available.. :(
> >
> > Cheers
> > Martin
> >
> > -----Original Message-----
> > From: urq-bounces at audifans.com
> [mailto:urq-bounces at audifans.com]On
> > Behalf Of Michael Hopton
> > Sent: 31-Aug-04 10:00
> > To: urq at audifans.com
> > Subject: [urq] 20vt ur-q Backfires - Thoughts?
> >
> >
> > I get quite a bit of backfiring from the 3B engine
> in my
> > '84 ur-q. It has the stock rear muffler and 3"
> pipe from
> > the down pipe. Stock turbo (250,000 mile!) K24.
> >
> > Sometimes between shifts and also on lift throttle
> I will get
> > back firing. Sounds good, but I am guessing you
> can have too much?
> >
> > I don't have an O2 meter but I am guessing rich
> spikes, or
> > possibly oil though the turbo seals?
> >
> > Martin's car also backfires, probably not as much
> as mine or he
> > just doesn't lift his foot off the throttle, which
> is true.
> >
> > Cheers, Mike
> >
> >
> >
> >
> >
> >
>
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