bowtieman81

iTrader: (35)

OK, in my turbocharged setup I have the pass O2 sensor in the crossover pipe (this pipe sees some backpressure from the turbo), and the drivers O2 is in my downpipe. Now, I noticed driving around I get mainly -2 thru -8 LTFT on bank 1, but +8 thru +12 LTFT from bank 2. Is the pressure in my crossover affecting my passenger side fuel trim readings? Should I tune mainly off the drivers side readings?

Billiumss

iTrader: (11)

That's why I was asking you questions in this thread:

https://ls1tech.com/forums/forced-induction/574547-did-some-test-driving-learned-some-things.html

My guess is that you should tune (WB 02 & LTrim) on the passenger side since the driver side gets the pass side exhaust to.

I am still interesting in this kit, have been for some time now.

ringram

Tune to the leaner side for safetly reasons.

Check for leaks etc to make sure its a real difference. You could also tune open loop.

Interesting thing is mine was different bank to bank by around 3% however with new heads, cam and ford svo injectors its now exactly the same bank to bank!

jimmyblue

iTrader: (11)

I would be concerned that the crossover exhaust might
be blending both, and mess up the fuel trimming because
some component of it does not respond sanely to trim
changes on the bank in question. Not quite like swapping
sensor lines but sort of. The trim will be trying to make
up for "random" things not under its control.

bowtieman81

iTrader: (35)

Well, it seems I had a slightly fouled plug that was causing some random misfires. That may have accounted for some of the differences bank to bank.

Bill, I get what you were asking now. I will see what the LTFT do without it misfiring. Maybe there will still be a difference bank to bank. If that is the case, then I will probably base most of my tuning off the drivers side.

Billiumss

iTrader: (11)

I hope you meant pass side. The stock o2 sensor is right at the manifold, no chance in hell the drivers side can affect fueling through 3 feet of exhaust pipe (crossover)

Just trying to be helpful as I'm interesting in this kit.

bowtieman81

iTrader: (35)

Well, I am not sure. I have read that the pressure in a crossover such as mine can affect the O2 readings. The same applies to widebands.
Here is a clip from the LC-1 manual:

Install the bung downstream from the turbo before the catalytic
converter. The high exhaust pressure before the turbo interferes with
the lambda measurement and the high exhaust temperatures
encountered there can damage the sensor.

I am open to some opinions. I hate to tune off the pass side if the sensor is not reading correctly. Then again, under light throttle/crusings condition there should be little backpressure in the crossover.

bowtieman81

iTrader: (35)

Man, I don't understand tech lately, I could not see your post Jimmy until just now

Anyway, can you explain what you mean by blending? Maybe a picture would help. Here is my crossover from underneath the car. The pass side O2 sensor is just upstream of the wastegate. Drivers side O2 is in the downpipe, so it sees exhaust from both cylinder banks.

Billiumss

iTrader: (11)

There's your answer.

Anything more than that, you'll be in PE mode anyways (open loop)

bowtieman81

iTrader: (35)

I see your point, but why would the readings from my drivers side be off real bad?

Also, the wideband is located in the downpipe.

Billiumss

iTrader: (11)

Not only is your drivers side O2 reading bank 1 (drivers side) it's also reading the pass side exhaust to, since all the exahsut from both banks pass over the drivers side o2. Thats why your ltrims are reading the way there are.

You are the first person I have ever seen post some real feedback about tuning this kit. I had my assumptions, but when you posted some info, you confirmed them.

Thanks for posting everything about your kit install and experiences!

bowtieman81

iTrader: (35)

Well, I think I will go conservative and tune for the leaner bank (passenger side). I appreciate the advice/help from you guys.

And Bill, I am not done posting yet. Still have a majority of the tuning to do. I plan to get the VE table dialed in, then adjust spark and check my spark adjustments by putting some 100 octane gas in.

And, if you are interested in this thing I could be talked into selling it later this fall.