LT headers and tuning...
Originally Posted by Starz T/A 17
rear o2 sensers need to get tuned out and if you take the egr and air pump off gotta remove those codes
Originally Posted by LS1Lust
Right, the computer will think something is wrong with your cats if you remove them. That will turn on your CEL, to tell you you need new cats 
TECH Addict
Joined: Jun 2005
Posts: 2,660
Likes: 14
From: England
I might be wrong on this but I thought with LT's and a catted Y you only used the front O2's which you need extenders for because they change location and the rears either need deleting or the use of O2 SIMS. As I say I may be wrong on this one.
As for tuning, well there's lots you can do it depends on your mods and setup. Removing torque management is a good idea as is raising your rpm limter and/or shift points (A4 only), A/F needs to be monitored and optimised as do the fuel trims. With an auto you can also select lock up points and kickdown points.
Cooling fan control can be adjusted, again for A4 guys you can alter the line pressure for firmer shifts if you want.
The list really does go on and on, best to check out the PCM forum for more info.
As for tuning, well there's lots you can do it depends on your mods and setup. Removing torque management is a good idea as is raising your rpm limter and/or shift points (A4 only), A/F needs to be monitored and optimised as do the fuel trims. With an auto you can also select lock up points and kickdown points.
Cooling fan control can be adjusted, again for A4 guys you can alter the line pressure for firmer shifts if you want.
The list really does go on and on, best to check out the PCM forum for more info.
Trending Topics
ima little confused here guys... so when lt's are installed you must get the rear O2's tuned out? what is the reason for this? so basically when lt's are installed your only running the front O2 extensions? i had shorties put on and the shop drilled O2 sensor plugs into my rand. tech. cats that didn't have a sensor plug... are shorties a different deal? someone please fill me in... sorry the thread hi-jack!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
The rear O2s are for emissions only. They let the car PCM know if the CATS are working properly. The front are the most important because they let the PCM know how to modify the A/F ratio. Shorties don't modify the stock CAT locations so unless you have changed out your CATS to high flow in your stock Y-pipe, you wont need to re-drill O2 bungs.
Tuning out the rear O2s will prevent you having to run O2 sims, which are only there to eliminate the SES light comming on after the rear O2's are deleted.
Hope this helps.
Tuning out the rear O2s will prevent you having to run O2 sims, which are only there to eliminate the SES light comming on after the rear O2's are deleted.
Hope this helps.
TECH Regular
Joined: Jan 2006
Posts: 469
Likes: 0
From: Tempe, AZ
Originally Posted by stillremains
I'm pretty sure the only way the pcm determines whether or not the cats are working properly is from the rear O2 sensors. I don't believe the pcm can establish whether or not you have cats by itself.
Most, if not all, aftermarket y pipes don't have the mounting boss for the rear o2s (regardless if they're catted or off road) so you need to either tune them out, get o2 sims, or live with the SES light
My Kooks catted y-pipe came with bungs for the rear o2 sensors. I still run the rears and I did not need extensions to connect them. I did, however need extensions for the front o2's.