99 B4 RSK wideband o2 sensor location

[RobMinhas]

Hey guys, I have a 99 B4 RSK that I want to install an aftermarket wideband sensor in to. From my research it seems that there is a narrowband sensor that I can remove and replace with the wideband, then get a narrowband signal from the wideband to go back to the ECU.

However, I can't figure out which sensor this is and how I would go about getting a narrowband signal to the ecu(what wire(s) to splice.

I don't mind getting a bung installed 6" from my primary turbo on the downpipe but I'd rather not put unnessecary holes in to a downpipe I will have serious difficulty replacing in Canada.

Any help is appreciated.

[Rosssub]

Nah the stock narrowband O2 sensor/ECU wont take a wideband signal, unless your running an aftermarket ECU. You'll have to put a new bung into the primary DP with the sensor going to an AFR gauge.

[RobMinhas]

Awesome Ross, thanks for the info. Just a concrete yes or no seemed damn near impossible to find on UkLegacy or SL-I.

Will weldd in a bung today or tomorrow then.

[RobMinhas]

Soo, took the car to the muffler shop to get a bung welded in on the primary turbo downpipe and was told the shop would remove the DP and charge an additional 2-4 hours of labor, so I figured I'd remove it myself. Turns out the nuts are seized and I don't want to remove the turbo, take it to the shop for the bung welding, then bring it back and reinstall it.

So if I were to get the bung welded on the secondary downpipe would I get accurate readings with the exhaust valve? I don't think it's always shut but I honestly do not know, figured I would ask.

[Rosssub]

The exhaust control valve is closed often enough to cause issues, so the secondary DP is no good. Unless it was in parallel permanently.

[ADIKT]

Are you running the wideband as a standalone ?

Which model do you have?

[RobMinhas]

 Rosssub said:

The exhaust control valve is closed often enough to cause issues, so the secondary DP is no good. Unless it was in parallel permanently.

Suppose that makes sense Ross, thanks for coming to the rescue again.

I was under the car today seeing if I can have any more luck removing the DP from the bottom and the more I looked I got curious. I know the optimal place for the sensor is 6-12" behind the turbo but would I have any sort of issue with accurate readings if I installed it directly after the primary downpipes cat? It's about 18" back from the turbo but it would save me quite the hassle and would actually make routing the wiring much easier too.

[Rosssub]

Not really certain on that one. I'd guess you would get a slightly different reading pre/post cat, but can't be that far off if people tune with an AFR sensor in the tailpipe. I think the minimum distance from turbo recommendation is more about heat and sensor life.

Here's a writeup on AFR sensors pre/post cat:

http://www.efi101.com/forum/viewtopic.php?t=6528

[Guest]

I wouldnt tune with it in tailpipe. You want the quickest response possible especially when tuning.

[boon]

 Rosssub said:

Nah the stock narrowband O2 sensor/ECU wont take a wideband signal, unless your running an aftermarket ECU. You'll have to put a new bung into the primary DP with the sensor going to an AFR gauge.

Not entirely true - most widebands these days have a simulated narrowband signal output from the controller. This means you can replace the narrowband as discussed with a wideband, you just have to feed the narrowband pin with the simulated signal.

[RobMinhas]

 ADIKT']Are you running the wideband as a standalone ?

Which model do you have?

Missed this post, standalone yes. INnovate LC-1.

[quote name='boon said:

Not entirely true - most widebands these days have a simulated narrowband signal output from the controller. This means you can replace the narrowband as discussed with a wideband, you just have to feed the narrowband pin with the simulated signal.

That being said, does a Rev A EJ208 have a narrowband sensor? I've only been able to spot one from the engine bay and its pre turbo so no beuno. Any ideas?

[Rosssub]

Yeah, in the left bank header:

http://postimg.org/image/lprxbj1nv/

[RobMinhas]

Ah I see, preturbo isn't really a good way to go with a wideband though from my understanding, things like heat and other things causing innacurrate readings. And Ross, I read that link you posted and I'm not sure how much of an issue installing the sensor behind the cat would be as I'm unfamiliar with the terminology and use of 'lambda"(we use completely different terminology here in North America and usually go by a differnent AFR scale[14.7:1 being stoichometric]), think you could give me your opinion on it?

[Rosssub]

Just different measuring units, like metric/imperial. Personally I would fit the sensor in the manufacturers recommended spot, so you know it's going to work/read as it should.

Have you tried soaking the primary DP bolts with a good penetrating fluid? Heating them up will help too.

[boon]

The ideal place for useful readings and sensor longevity is after the turbo but before anything else.

Unless there's a cat in the downpipe I'd just get underneath and knock a hole in that then get somewhere competent to weld a bung on. Took all of 15 minutes on my V7, although I have no idea where the downpipe merges on a twin-turbo and presumably you would want the sensor just after the merge?

[RobMinhas]

Cat in the primary downpipe, shouldn't really matter before or after the merge as teh exhaust gases meet prior to the turbos.

Innovate says 24" behind the turbo but before any cats. Cat will cause lean reading. Unfortunately my cat is maybe 10" from the turbo which puts me in a crappy spot. Either I'm too close to the turbo or after the cat. Any thoughts?

[Guest]

Meh stock on a wrx is 3in from turbo youll be fine.

[lachlan]

while it is out you have to loose the cat . be extremely stupid not to . . will make car lots better in every way too .

my aem is about 8 inch from turbo . not far past the stock location

[RobMinhas]

 evowrx']Meh stock on a wrx is 3in from turbo youll be fine.

Eh, good enough for me.

[quote name='lachlan said:

while it is out you have to loose the cat . be extremely stupid not to . . will make car lots better in every way too .

my aem is about 8 inch from turbo . not far past the stock location

Decatting the primary downpipe leads to boost spiking and overspooling, would rather not do that.

[Guest]

 RobMinhas said:

Eh, good enough for me.

Decatting the primary downpipe leads to boost spiking and overspooling, would rather not do that.

Add a boost controller and it wont. Manual or ebc both better than what they have stock.

[RobMinhas]

Would that work? I'm far from the smarter folks who have owned these cars and it's a consistent and commonly stated fact that it causes over boosting and if a boost controller could stop that I feel someone would have tried it already.

[Rosssub]

 RobMinhas']Decatting the primary downpipe leads to boost spiking and overspooling, would rather not do that.

Add a boost controller and it wont. Manual or ebc both better than what they have stock.

[quote name='RobMinhas said:

Would that work? I'm far from the smarter folks who have owned these cars and it's a consistent and commonly stated fact that it causes over boosting and if a boost controller could stop that I feel someone would have tried it already.

Yip, MBC/EBC will sort it.

[RobMinhas]

Well I feel dense. Everyone seems to just spout as fact that the decat causes uncontrollable overboosting. Looks like I'll be doign that.