I'm purchasing a new header from Walt/Delta Group/OPM for my ITA CRX. I know they don't build them to be used with O2 sensors because it is considered a full race header. What do I face if I don't use an O2 sensor? Is it not an issue since the engine is at wide open throttle most of the time and the ECU is in running in open loop? In order to tune for part throttle, wouldn't an O2 sensor be needed?

 

if your running open loop on the program, then you dont need it.
but the car AF's would have to be tuned to run open loop al the time without ecu correction.

 

At the moment, I am using the stock ECU without any program or chip. So the only time it's in open loop is at WOT (which is all the time). Since this is the case I should be able to get away with it until I have the ECU reprogrammed. Or I might have to have him weld an O2 bung.

 

you will have a check engine light..
what motor are we talking about?

 

I am not worried about a CEL as long as the removal of the O2 is not effecting performance.

It's a D16A6

 

the cel will just make it run in open loop, im not sure of your mods and what not, but check part throttle drivability with the stock ecu's maps.
the Af's could be off.

 

Other then an intake, header and 2.5" straight through exhaust, the motor is relatively stock (per the rules). I am sort of putting the cart before the horse since am getting a new .040 over motor shortly.

I suppose the easiest thing to do would be to remove the O2 and check the driveability. But then again, the butt-dyno is that accurate.

 

if your just doing this waiting for the other motor, then yeah, i guess just drive around and test with butt dyno; but if not hook it up to a wideband.

you could just get a bung welded on the cat/test pipe if you dont want to mess with the header..