WB O2 Location

[Steve 00RT/10]

I have a friend who self installed a 5 pound Roe on his 98 RT/10 in the winter of 2006. It's never been tuned. At the time of install, he put a bung in middle of the side sill area. He has no cats, but the bung is downstream from his race bullet muffler -- where the cat used to be. I think the addition of a new Ford GT that same winter turned his attention from the Viper some. He's put over 15,000 miles on the GT since purchase. This winter he hopes to sort out the Viper and do some logging in the spring. I can guide him some, but don't know if that bung location is a preferred spot. Mine is in the collector area. I'm guessing it shouldn't be an issue, but thought maybe there might be some other opinions on the optimum O2 location

Thanks--Steve

[KenH]

I have never seen one installed more downstream than the turnout from the collector, but my guess is that it should be OK. A lot of dynos use sensors at the exhaust tips.

The only downside I could see is that the A/F vs. RPM reading will be more delayed the further down the pipe you go. Also, there is more chances for an air leak in the system upstream to cause an incorrect reading.

[Steve 00RT/10]

Originally Posted by KenH

I have never seen one installed more downstream than the turnout from the collector, but my guess is that it should be OK. A lot of dynos use sensors at the exhaust tips.

The only downside I could see is that the A/F vs. RPM reading will be more delayed the further down the pipe you go. Also, there is more chances for an air leak in the system upstream to cause an incorrect reading.

Good points. I have wondered the same thing myself about the dyno placement. I have some real life experience with potential air leaks.......or just to far downstream to get accurate readings....

The 01 car we bought last year had one of the early 5 pound Roes...the ones which couldn't be logged. It was tuned on a dyno in 2003 ( and never touched again) and made pretty good power from the sheet I have.....554HP/586TQ. That's with a lightweight flywheel. Having been through the install/tuning process with our 00 car, I felt blind without a WB to see what was going on. I sent the VEC in for upgrade to logging status and installed a WB in the turnout area like our 00. The initial logs showed AFR at WOT to be high 9's to mid 10's...........way rich!!. This could indicate an air leak somewhere, although I have had the system checked.....or..........possibly being that far downstream is introducing more air to the equation. At any rate, I have removed a substantial amount of fuel from the setting that made the above numbers.

I think I'll recommend he install another bung at the turnout.

Steve

[Bolt]