Do you need O2's? 2 bar SD
 

On a turbo application, HP Tuners 2 bar SD operating system... what do the front O2's do? Can I leave them out? rears are already long gone and shut off.

Fronts are closed loop. If they are out you will be running 2bar SD OL. Some people do it some don't. Most people who do are usually purpose driven cars. I myself am running 2 bar SD with front 02's.

^+1

i dont run 02's because i like running leaded race fuel and that kills 02's. but it is a pain in the ass sometimes when the weather starts changing alot as it can not adjust.

Reason I ask is my friends BMW we are building, we went through the harness and eliminated all the unneeded wires.... and I think they got eliminated. It would be a pain in the ass to probably rewire them. Just wondering if it will work w/o. Would it just take longer to tune and dial in the VE table? Like you'd have to tune it with each weather change?

Front o2's I have found are easily fooled by weird cams and non pump gas, so I would ditch them in any case.

The problem is that with SD, your tune is going to be weather effected WAY more than a MAF tune would be, so the front o2's would help if you are going to do a 100% pump gas / stockish cam setup.

maf + no front o2's = awesome

SD + no front o2's = not so much.

How about E85 running the front o2s?