A Question for Those with EFI Engines

[Zaphod B]

I'm considering running fuel injection when I order my engine.

Where are you EFI guys putting the O2 sensor? Normally you'd want to put it after the collector, but the collectors on the side pipes are outside the car....

[DucatiThunder]

Mine is under the passenger sidepipe. Its underneath just aft of the 4 pipes into one. Cant see it from under or above ... fairly unnoticeable.

[Zaphod B]

Originally Posted by DucatiThunder

Mine is under the passenger sidepipe. Its underneath just aft of the 4 pipes into one. Cant see it from under or above ... fairly unnoticeable.

Does that work well for you, sampling from just one pipe?

[FUNFER2]

You want to read both side of the motor with side pipes, not just one bank. If you had dual exhaust with a Y or X pipe exiting to one or two tail pipes, then that's fine. Believe me, we've tested systems on the chassis dyno.

[DonC]

In general it will depend on what type of 02 sensor you're using. Narrow band sensors don't have heaters so they need to be closer to the exhaust port to maintain the temp needed to be accurate. A wide band 02 sensor can be located farther away (as in the collector) since it has it's own heater element.
It's also preferred to mount them somewhere between straight vertical and 90 degree to prevent condensation for collecting on the elements and fouling them.
I'm using a Mass-Flo system with narrow band sensors and mine are located in one of the primaries on either side of the engine. Not an ideal solution but close enough to keep them hot and give me a reasonably usable reading.
DonC

[DucatiThunder]

Originally Posted by Zaphod B

Does that work well for you, sampling from just one pipe?

Yea, I havent had any problems. Im running Fast EFI with my Inglese 8 stack. Not sure how you would run it any other way with the cobra set up.

[Avmaviator]

Our FAST EFI system will be mounted in the collector, outside the car, as it was recommended by FAST and my engine builder. On the dyno it ran great. And we saw the same AF numbers on the two different banks. The dyno had an O2 sensor on the other side, also in the collector, to compare readings between the EFI sensor and the dyno sensor (and also left and right like I mentioned).

Unless something is going wrong on one side due to a mechanical issue or something, you should be getting correct information for tuning the whole engine by using only one side.

[vector1]

one bank or the other i don't think matters except you do not want any air leaks at the flanges or collector to primary connection. i have a sensor in a primary pipe but not running efi and i would think the pulses or variances would need to be averaged or the sample rate reduced.

[lamaluv]

My O2 sensor is located where the collector and side pipes meet. I am running a FAST EZ system and have not had any O2 sensing problems in the 5 years I have had it on the car.

[Zaphod B]

Thanks, guys.

[Zaphod B]

Originally Posted by lamaluv

My O2 sensor is located where the collector and side pipes meet. I am running a FAST EZ system and have not had any O2 sensing problems in the 5 years I have had it on the car.

lamaluv, if I'm seeing the picture correctly, you have the sensor angled downwards, which is contrary to the recommendation to have it angled upwards (in order to avoid condensation getting on the sensor). Yet you've had no issues in 5 years. Cool.

[lamaluv]

The picture of the sensor on the car is deceptive as the wiring from the sensor hangs down making it look like it is angled down. It is actually tipped up which is shown better in this picture. The hole is just above center on the collector pipe.

[Zaphod B]

Originally Posted by lamaluv

The picture of the sensor on the car is deceptive as the wiring from the sensor hangs down making it look like it is angled down. It is actually tipped up which is shown better in this picture. The hole is just above center on the collector pipe.

OK, I see. Thanks much.