Wideband with Pre-Cats

[robertearl]

I have a 2000 Corvette with a freshly rebuilt motor. ( cam , port , etc. ) I have purchased HP tuners but I have a question about a wideband sensor. This is a California car so it has small pre-cats just after the exhaust manifold. Is it acceptable to put a wideband after the pre-cats but before the real cats??? This is the location of the front O2 sensors. The pre-cats are within a foot of the exhaust manifold so I believe that is to close to mount it there.

Since the O2 sensors are after the pre-cats anyway, is that the proper location????


Reb

[12secSS]

If you can, your Corvette has an oxygen sensor just pasted where the "primaries" merge before the Pup cats. This would be the ideal place to mount the wideband, if you physical can reach it. If not, then the location after the Pup cats would work as well. But keep in mind that the readings will be skewed, due to the cats doing their job, some report around 0.2 difference while other reports as much as 1.0 afr point difference.

[robertearl]

On mine, the pre-cats are before the first O2 sensor. The pipes do not merge at all. There is an H pipe after the main cats. The pre-cats are only about 1 foot from the exhaust manifold.

Reb

[Dirty Howie]

Put some long tubes on there


DH

[Billf6531]

My 2003 C5 had factory pup cats. The front O2s were in the cast manifold, though, not between the pup and regular cats.

I installed the 2-cat H-pipe from a Z06 ($100, used, low-mileage) and installed w/b bungs before the cats. Lots of room, and according to what I've read, these cats are more efficient to compensate for the missing pup cats.

Just a suggestion.