Tuning an LS3 with Kooks Exhaust?

[RumRunner]

I'm planning on bringing my GTM to a local performance shop to get tuned. I have a crate LS3 with Kooks exhaust.

I've been throwing a few codes as I've been driving:

* O2 sensor heater codes which apparently are common with long tube headers. Something to do with the response time on start-up. This can be corrected in HP Tuners (or so I'm told).

* Also throwing a throttle position sensor error immediately after WOT (when I let up on the go-pedal) that puts me in limp mode. Clear the code and everything comes back fine. That one still needs tracking down.

So here are my questions for anyone that's tuned with the Kooks exhaust:

1. Did you use a wideband O2 sensor during the tune process? If so, where did you install it?

2. Has anyone running the Kooks had any problem with the O2 sensors being only 4 inches forward of the cats? Just curious if the O2 sensors continue performing as the cats heat up. I know the O2 sensors usually work in a very hot environment, but those cats get toasty!

Thanks for any help you guys can offer.

-Michael

[Kempo]

If you are having codes issues most of them can be turned off with HP Tuners. You have to check if it's getting the code because of a real issue or maybe the PCM it's not seeing any of the systems that are deleted on the GTM like emissions or so.

Your O2 sensors will be ok in the GTM exhaust. On my track car the O2 sensors live in a way hotter environment and thy last forever. Are you running 2 or 4 O2 sensors?

Now for you questions

1) yes a wideband o2 sensor it's a must. Of the shop that it's doing the tuning Tells you it's not needed get out of there ASAP. The stock sensors are narrow band and don't have the resolution required for tuning. As for placement you can install it at the exhaust tip, weld a dedicated bung for it in the exhaust (that's what I did on mine) or on one of the kook's bungs if you are tuning only two o2 sensors but you will be reading only one cylinder bank. I welded my bung in the x-pipe.

2) O2 sensors will be fine

Hope this helps.

[RumRunner]

Thanks Hugo. One more question - I understand you welded a bung in the X to read from both banks, but it seems the reading would be incorrect if the wideband O2 sensor is after the cats? Or did you delete the cats? Or can the wideband O2 be after the cats? I don't know much about tuning, but just enough to make me wonder.

-Michael

[kabacj]

I agree with Hugo on the wideband. Thats what I use.

Mine are mounted forward of the cats. I only use 2 but the Bosch ECU I use is setup so that it reads both banks of cylinders with this setup. The 02 sensors have gotten REALLY hot and they are fine.

For track work you need to shield your CV boots from the radiant heat from the KOOKs cats or swap out the cats for open pipes when you go out on the track.

Happy New Year!

John

[Kempo]

I don't have cats in my car. Ideally you should install your wideband before the cats. Installing it after the cats is acceptable but you will get a slightly leaner AFR reading. When installing the bung try to keep it in the upper part of the pipe. From 3 to 9 o'clock. This will help to keep condensation moisture away from the sensor and make it last longer.

[RumRunner]

Hugo, John,

Thanks for the words of wisdom. It will probably be a few weeks before I get a chance to get it tuned - I'll try to keep learning until that time.

-Michael