Re: [DML] Cat removal

[Gus Schlachter <gus@xxxxxxxxxxxxx>]

Martin,

As you well know, there are other differences in the USA/EUR DeLoreans 
than just the cat.  I'm not versed in these differences, but I know that 
it's seldom a simple matter to alter a single variable within a complex 
system.

Removing the cat on US vehicles may or may not increase performance, and I 
would like to see a dyno test that shows the difference.  Removing the cat 
will almost certainly increase emissions.  If I could get another 10 or 20 
HP by cutting out the cat, I'd be under there with a hacksaw right now. 
But in truth I think it's 1 or 2 HP, which hardly seems worth the effort 
(let alone the extra emissions).

Don't worry about the higher emissions in your Euro-spec cars...you'd need 
to leave every vehicle in Europe idling 24/7 before you'd even come close 
to catching up with the USA.  We're #1, woo hoo!

Gus Schlachter
VIN #4695
Austin, Texas



dmcnews@xxxxxxxxxxxxxxx wrote on 09/23/2005 07:39:12 PM:

> Hi Stephen
> 
> You may like to actually try driving a DeLorean that has been de catted 
> - and by this I do not mean simply gutting the contents of the existing 
> cat*. The exhaust note changes noticably and the engine is without 
> question perkier. I have no dyno sheets to prove this, but if you can 
> find one owner who has a cat bypass pipe installed and did not 
> experience greater performance, I'll eat a cat for tomorrow's breakfast 
> :-) Meoww
> 
> Remember the DeLorean engine is unusual for a PRV in that it is catted - 

> for 1981 this was very rare. ALL the european versions run considerably 
> more horsepower and this all comes down to the fuel system not requiring 

> a lambda system to keep a perfect  mixture. Running rich can be good for 

> performance if tuned properly. Our euro converted engines are 
> considerably more powerful, still running a stock exhaust, cat bypass 
> and european B28E ignition and injection systems. One customer 
> discovered his clutch was worn out immediately after collecting his car 
> after the upgrade.
> 
> * I have one customer to whose car I fitted a cat bypass pipe. His old 
> cat had a perfect hole strait down the middle. Despite this, he still 
> reported improved pickup and crucially a marked increase in fuel 
economy.
> 
> By suggesting the DeLorean's stock exhaust is "tuned" is rather amusing 
> really :-)
> 
> FYI catalytic converters were not mandatory in the UK till 1994 so we 
> can legally remove them over here, and sell the pipe to do so. Are we 
> being environmentally unfriendly? I suppose so, but we are burning less 
> fuel doing it, so you could argue we're actually cutting down on CO2 
> emissions!
> 
> Martin
> 
> Stephen Schlachter wrote:
> 
> >See my previous posts about removing the cat.  Doing so increases 
> >emissions, and adds no performance (and may even hinder it).  Just 
> >because you can't see the extra pollution doesn't mean it isn't there, 
> >and backpressure is part of the overall exhaust tuning.
> >
> >The only reason to remove the cat is due to malfunction...and then, 
> >only to replace it.  If someone has a dyno test that demonstrates a 
> >measureable improvement in performance by increasing pollutants, I'd 
> >like to see it.
> > 
> >
> 
> 
> 
> 
> 
> 
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