RE: [Tech]: O2 sensors

[Randy Block <RandyB@E-Risk.com>]

Ok, now you've peaked my interest.
What if you are running the early (1981-US/CA) CIS system and you have the
Oxygen sensor but removed the Cat.

Question is:
Can/Should I disconnect the O2 sensor from the system and just run the
signal wire to my air/fuel mixture gauge?
I would obviously have to reconnect it when I put the Cat back in and have
it smog'd every 2 years.
Will I notice any gains or will this be a detriment to the CIS system?
Thanks,

Randy B  "I hugged a tree last week for pennance"
Mars 81S - techtonics tuning 1847cc 8V
Cosmos 81S - future project - dreaming of 200-220hp.
87 Jetta GLI 16V - daily driver 

	-----Original Message-----
	From:	Jonas Karlsson [SMTP:jonas85k@hotmail.com]
	Sent:	Monday, December 04, 2000 9:13 AM
	To:	Captnbr@aol.com; roccophil@mindspring.com;
scirocco-l@scirocco.org
	Subject:	Re: Tech (RANT) : O2 sensors

		>From:	Captnbr@aol.com <mailto:Captnbr@aol.com> 

		>roccophil@mindspring.com writes:
		>
		><< O2 sensors - for those of you who disconnect them -
DON'T!
		>
		>Yeah, ok I know I'm a dumbass.  But , is it true that the
euro 16v's do not 
		>have O2 sensors?  I thought I heard that once before. And
don't they put 
		>out a little more HP.  So are they just missing the o2
sensor >or do they 
		>have a completely different engine management system. later

	Not that I'm an expert on the euro 16v fuel systems or anything, but
here's a lowdown on some FI basics.
	First, exessive unburnt fuel will kill a catalytic converter in
no-time. 
	That should scare you 16V guys a bit (with the integral downpipe/cat
unit. 
	$$$)

	The famed euro 16v injection systems were straight CIS. If there was
no cat used, as Euro listers indicate, then there was little need for an O2
sensor.  The system as a whole was designed for this however. Most of the
power increase seems to be due to lack of cat and 50mm intake/euro cam.
	KE-jetronic (AKA CIS-E) that is used on US cars was designed to very
precisely control the air-fuel mixture (to reduce emissions and prevent cat
death). To do this there needs to be a O2 sensor (connected). Merely
disconnecting the O2 sensor will not yield a euro system but will cause your
car to run like crap. The system will not be able to contol A/F mixture, and
performance will suffer.
	Basically maximum performance comes at a slightly rich mixture.
Bosch knows this (that's what we pay them for) and they design FI systems
that work very well to maintain a mixture that is on the money. Modifying
the stock system (even if you know what you are doing) usually is not very
successful and requires many hours of testing to make sure that everything
works right.
	Until you're pushing 180 HP the stock system will work very well to
deliver fuel at the proper amount.
	HTH
	Jonas
	85 Scirocco 2.0
	78 Scirocco 1.8
	For direct reply: jonas@metabolex.com <mailto:jonas@metabolex.com> 
	http://www.geocities.com/scirocco2l8v
<http://www.geocities.com/scirocco2l8v> 

	
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