Seems there will be problems when running a PR3 or PW0 ECU with a Turbo Manifold.

PR3 & PW0 are OBD0 ecu's from JDM DA's & EF's.
The ECU's use two O2 sensors to tune each pair of 2 cylinders.
1 O2 for cylinders 1 & 4. And the other O2 for cylinders 2 & 3.
This isnt a problem if you're NA and have a 4-2-1 header.

If you run a 4-1 header, the ECU can no longer tune for each cylinder.
There is no way to tap in O2's (using O2 bungs) and have one O2 reading for cylinders 1 & 4 and the other O2 reading for cylinders 2 & 3. You could tap into one runner pipe for 1 cylinder ..that way ECU would at least read cyl 4 & cyl 3.
It would run, but the cylinders 1 & 2 can run lean or rich compared to the others. Also, below 4k rpm it will run shitty "sometimes" (in closed loop op.)

I did the search and asked around, but nobody gave a direct answer.
How would it be possible to run a PR3/PW0 ECU with Turbo Manifold?
All 4 exhaust pipes go into 1 before reaching the turbine.
A custom 4-2-1 T-manifold could be made that would allow you to place O2 sensors before the turbine, but O2 sensors usually placed after the turbine in the downpipe, right?

All this confusion came up when a customer with a B16a swap in a 90-91 teg wanted to go Turbo.
The current ecu harness is for a PR4 (nonvtec ecu) rewired to run a PR3.

 

um,

this may be too simple to have been noticed, but it wont matter where the bungs go, as long as there are two and they are close enough to the exhaust ports to get hot enough.

honda was trying to be clever when they did the early PGMFI ecus i think.

teh two o2 sensors were meant to even out hte whole system...

but with a turbo, the o2 sensors when on hte single runner will tell the ECU that there is the same O2 content comming from each pair of cylinders, and will tune the injector PW to suit this.

will this "two-single sensor" tuning be a problem with a turbo application?

have i been clear?

hth,

t..

 

Yes, we are worried about the "two-single sensor" tuning being a problem with Turbo.
I imagine that any rig would work at full throttle (open loop). But during partial throttle (closed loop) will the ECU tune properly? You can't just have both sensors adjacent to each other in the downpipe, right?


[Modified by Quick 200k Mile Motor, 2:47 AM 6/17/2002]

 

why not? they would get in the way of the exhaust flow - yes,

but from a closed loop point of veiw , both pairs of cylinders will be seen as independant by the ECU cause you have two sensors- but will be the same o2 content, and may not need to be trimed as much.

and UNLESS you have a problem with your injectors/fuelrail/EFI then you usually wont have too much of a o2 difference between cyls that needs to be trimed anyways, so really should be no problem.

unless i have missed something?

(i hope someone else has some comments to make...)

hth,

t..

 

You could always splice up the wires and hook them all up to one o2 sensor. Seen it work, runs nice, but runs rich! Better to run rich than lean.

 

have the ecu chipped by http://www.hyperducktuning.com

they can remove the 2n'd O2 so the ecu won't read it


[Modified by 89civicdx, 2:27 PM 6/17/2002]

 

I have a Mugen ecu program for the PR3 ecu that disables a few sensors including the 2nd 02. Hit me up if you're interested...

As for the PW0 ecu, I do have a Feels' program for it, but all sensors are enabled.