Downpipes without cats question.
07-29-2001, 06:56 PM
#1
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Downpipes without cats question.
I am thinking of getting down pipes custom made for my car. Question I have is what do I do with the 02 sensors? I am sure it will trigger codes in the computer that I am running without cats, how do I overcome this?
Thanx
Thanx
07-29-2001, 07:07 PM
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Re: Yeah, but are they worth the prices some are charging? More than a G for a set.
Nobody said horsepower is cheap, especially for the S4. Put it this way, do the mod, re-map the chip with the exhaust, and let me know what you think. The reality of it is about $4,000 - $6,000 depending where your starting point is.
07-29-2001, 07:23 PM
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For LS1 engines there is a product called an O2 simulator
This product plugs in to the after cat O2 sensors and simulates the correct readings to avoid a check engine light.
You can learn more about this from the LS1 forum at www.ls1.com. Check some of the sponsor vendors as many carry this product.
Also, you might call APR and ask how APR deals with this problem as APR sells downpipes that include cats and test pipes that are easily interchanged.
You can learn more about this from the LS1 forum at www.ls1.com. Check some of the sponsor vendors as many carry this product.
Also, you might call APR and ask how APR deals with this problem as APR sells downpipes that include cats and test pipes that are easily interchanged.
07-29-2001, 08:24 PM
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well I did the same for my A4.........(More)
and I had a 3" custom D/P made from the turbo back and he put the o2 sensors near the stock location on the new pipe and it has been 1 week now and I have no check engine light. hope that helps if not please feel free to e-mail me
07-29-2001, 08:31 PM
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You can also make one yourself with a few dollars in parts from Radio Shack
I don't know the exact schematic but I think you just need a voltage divider. Without the cats, the O2 sensor is going to put out what the front is (0-1volt oscillating). You just need to step this output down to say 0-300mv, as if a cat was in front of it. The plans are probably out on the net somewhere.
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07-29-2001, 09:58 PM
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Exactly what I was going to suggest.
Tons of companies make them for all different kinds of cars. All it is, are some resistors packed together. Not too hard to make. You have to play around with the right combo (correct reading) so you don't throw a code.
Any tuner would be able to help you out.
Any tuner would be able to help you out.
07-30-2001, 04:48 AM
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Running with no cats will tank your gas mileage!
The o2 sensors across a cat are necessary for the ECU to compute fuel requirements when crusing. No effect on acceleration. You will fail emmisions testing.
