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

Tue Aug 31 17:19:56 EDT 2004

Don't go that far upstream, Mike. :-)

Instead of a EFI 10VT owner, what we need to answer this question is a 
musician. Or a sound engineer.

The sound produced by a fixed amount of hot gas exiting through an 
aperture will be different if this aperture is a big one (10V) or 2 small 
ones (20V).
More, the exhaust manifold is not a kind of flute, in a way?

Musicians: Please chime in... 

Louis-Alain

"Michael Hopton" <Michael at siliconoptix.com> 
Sent by: urq-bounces at audifans.com
2004-08-31 16:41

To
"Brandon Rogers" <brogers at terrix.com>, "Rich Letsinger" 
<ricoletsinger at yahoo.com>, <urq at audifans.com>
cc

Subject
RE: [urq] 20vt ur-q Backfires - Thoughts?

Maybe it is the CIS, can anyone comment from a 10vt
with EFI?

Cheers, Mike

-----Original Message-----
From: Brandon Rogers [mailto:brogers at terrix.com] 
Sent: Tuesday, August 31, 2004 4:42 PM
To: Michael Hopton; Rich Letsinger; urq at audifans.com
Subject: Re: [urq] 20vt ur-q Backfires - Thoughts?

ehh I don't know about that.  My WX with K24 sounded just like it did
when I
had the K26, ISTR.  But I could have early onset memory fade.....

that said, I do not understand why the 20V sounds more refined, less raw
than the 10V.  I mean, it's still 5 cylinders with the _exact_ same
exhaust
from turbo back....

Brandon

----- Original Message ----- 
From: "Michael Hopton" <Michael at siliconoptix.com>
To: "Rich Letsinger" <ricoletsinger at yahoo.com>; <urq at audifans.com>
Sent: Tuesday, August 31, 2004 12:13 PM
Subject: RE: [urq] 20vt ur-q Backfires - Thoughts?

Rich,
You could be right with the definition, so this is pops and
bangs out the exhaust and not into the inlet manifold.

I get it to a much lesser extent on the 10 valve WX. I do
miss the rumble and deep throaty sound of the 10vt, I think
the K24 muffles the sound much more.

Cheers, Mike

-----Original Message-----
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
Behalf Of Rich Letsinger
Sent: Tuesday, August 31, 2004 1:42 PM
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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