can a setup be tuned without there being any o2 sensors on the car? i've never run any o2's on my cars and not even with my turbo setup either. I was just wondering if it can still be tuned this way. this is a 89 mustang with a single 70mm and mild H/C/I. all my cars have ran better without any.

 

" all my cars have ran better without any. "

Better than what? A set up using them?
Given you have experience tuning without, I'd guess using plug reading, egt, etc is what U R doing??

 

It's generally ill advised to go with out tuning and some kind of way of getting feedback from the engine. It "can" be tuned using plug cuts or EGTs only, but I definitely wouldn't file it under good ideas. EGTs are far less mainstream and subject to variances depending on placement, timing etc. so they aren't necessarily the best thing for fuel. I'd keep some spare head gaskets handy. JMO on it.

 

I spoke with the tuner today and he said it didn't have to have any o2's because they could be turned off in the tune anyway. i'll have a wideband on the car but I dought i'll use any o2's . to much bad luck using them in the past.

 

I'm *assuming* by this post you are talking you'll have a wideband in the car for tuning purposes and when you reference o2's your talking about the factory O2 sensors. Disabling the narrow band o2's and using the wideband to tune I would believe is standard practice across the board, at least this is how I've tuned cars for the past 5 years. The tuner *should* disable STFT (Short Term Fuel Trims), LTFT (Long Term Fuel Trims) and the narrow band o2 sensors so they dont have a affect fueling and tune off of the MAF or MAP using the Wideband. Now in saying all of this, IF your tuner tunes the vehicle correctly, if your narrow band o2's are in good shape, I would run them. The computer will use them for idle and cruise closed loop fueling to do slight adjustments, but in the tune disable STFT/LTFT being used open loop, that way when you "floor it" it goes open loop and goes off the Wideband calibrated tune. Also a side note, I would keep the wideband with somesort of gauge inside the car, just as a security measure because its a quick reference just in case say your fuel pump starts loosing pressure, fuel leak, etc you can "get out of it" hopefully quickly enough to save the engine.. Hopefully that all makes sense...

 

thanks bowtie, yeah i'll be using a wideband inside to monitor the readings.