o2's placements

[Turbo2gnx]

i have a set of LT headers and wondering how far should the upstream and downstream be apart? the set i have they are 3-4 inches apart. i dont have o2's installed as i did something stupid and cut the stock wiring harness for both downstream o2's to extend the upstream o2 harness. i plan on getting the harness repaired and installing the downstream so i can try to tune VE tables. ive looked and aske how to tune VE tables without the downstream o2's with no returns on how. so again how far should they be to work efficient also no cats.

[rays04gtx]

there should be 12in min, 18in Max., Upstream in Headers roughly 4-6 after the merge in the collector., if you run Open headers, you need at least 24 Inches of pipe to keep reversion from giving false readings...................if you delete cats....the rear(downstream o2's) won't see much of a difference.

[Turbo2gnx]

there should be 12in min, 18in Max., Upstream in Headers roughly 4-6 after the merge in the collector., if you run Open headers, you need at least 24 Inches of pipe to keep reversion from giving false readings...................if you delete cats....the rear(downstream o2's) won't see much of a difference.

thanks for replying and the info! how to tune VE without the downstream or am i out of luck?

[HaasExp]

how to tune VE without the downstream or am i out of luck?

Just use your LTFTs+STFTs to tune your VE table in CL and the WBO2 in OL. You dont need downstream NB sensors to tune, just the upstreams. If anything, turn off your downstream O2 sensors and dont worry about them

[401Alex]

I'm asking on the subject of O2 placement and or Delay with long tube headers on a 2010 5.7 charger with a cam. It was tuned and runs good but after seeing it graphed on the O2s (upstream) they will not get ready every thing else outside of O2 and EGR is ready has high flow cats and rear O2s is there a way to get the front O2s to be more normal and not drop out of closed loop when you are driving?