Stoner_Banks

whats up guys, I need some help...i have a 99 ls1 camm'd,hardened internals,superchipp'd with a few other bolt ons, I am now about to start working on my exhaust. Just picked uo some custom LT's with an x-pipe and i was gonna run it dumped with dynomax bullet mufflers. would that sound good or too loud? but my concern was my o2 extensions, dont the late gen f-bodies have 3 o2's? isnt there one in the y-pipe? do i have to drill a hold in my x pipe and create a o2 plug? someone plz shoot me some feedback, i plan on working on my exhaust this weekend.

demonspeed

iTrader: (7)

There are 4 O2's -- two on each bank; one pre and one post converter. When doing long tubes one only runs the pre-converter O2's. These should go in the header collector.

Stoner_Banks

okay so your saying with my LT setup I would only have to run 1 o2 sensor per collector right? none in the x pipe?

demonspeed

iTrader: (7)

Yes. You'll get an engine light unless you run simulators in the rear O2 plugs -- or get a tune.

eagle-co94

Is there a device to plug into the harness where the rear o2's go? I don't currently have rear o2 provisions in my exhaust and don't want to have to install bungs just to run non-foulers.

-edit Found them: http://www.afterthoughtsauto.com/o2sim.html

Anyone know of another source?

demonspeed

iTrader: (7)

One just unplugs and removes the rear O2's and leaves the plug hanging. That's it. The O2 sims just turn off the SES light, so if you don't mind that light then you don't need to get them.

eagle-co94

So other than a light in the dash the computer won't change the tuning? I don't want missing o2's to have a negative effect on mileage and/or performance.

demonspeed

iTrader: (7)

Mileage will suffer slightly because it'll start trying to compensate for the lack of signal coming from the rear O2's. The O2 sims simply trick the computer to thinking that the rear O2 sensors are working.

Considering those simulators will cost you $96 for the pair, you can spend $50 more and get a mail order tune from a place like Frost that will not only remove the SES light, but also tune the car to actually take full advantage of the headers and other mods.

eagle-co94

That sounds like a great idea. My car is at the shop right now getting the cat-back and headers mated together so I can get my hearing back. I'll get with a local tuner to see what his magic want can do.

demonspeed

iTrader: (7)

If you've got a local guy (and if you're on a tight budget), he might just be able to turn off those rear O2's and not do anything else for next to nothing.