March 10, 200719 yr I just picked up a WRX downpipe that is destined for my EA81T coupe. The WRX downpipe has the O2 sensor somewhat downstream of the turbo. The EA81T coupe's stock location for the O2 sensor is in the crossover pipe right under the turbo. After my wagon's reliably running, I'm yanking the engine to the coupe and doing some maintenance. This will include an upgrade to an EA82T watercooled turbo and changing the O2 sensor... and I might get crazy and weld up a header at Brian's. ???? Does it matter (to the EA81T ECU) whether the O2 sensor is before or after the turbo? I'd just as soon have it in an easier-to-maintain location... which would also let me skip installing a bung if I make a header. thanks!
March 10, 200719 yr I'm no expert, but I don't think it would matter moving it to infront of the turbo. Just as long as it is in front of cat it should be alright. Oh, you might want to a foot or two back from the heads though, just incase the heat messes it up.
March 10, 200719 yr I'm no expert, but I don't think it would matter moving it to infront of the turbo. Just as long as it is in front of cat it should be alright. Oh, you might want to a foot or two back from the heads though, just incase the heat messes it up. I'm with him. I don't think it'll matter much. The exhaust doesn't change from one side of the turbo to the other. I think you should go nuts and do a wrx turbo and intercool it. Maybe a small front mount or a awic. Just to see what it can do. Stock wastegate for the td04's is 9psi iirc.
March 10, 200719 yr I think you should go nuts and do a wrx turbo and intercool it. Maybe a small front mount or a awic. Just to see what it can do. Stock wastegate for the td04's is 9psi iirc. I have no experience in this matter. But... I would of thought the WRX turbo is a bit big for a EA81. There would come a point where you would just be spending more exhaust enegy spooling the turbo then what you would be getting from it. What about one of those smaller TD035 turbos? I would think a small nimble turbo would be a better choice on a EA. But like I said, I have no experience here.
March 10, 200719 yr Author Thanks for the inputs, guys. I actually have an intercooler for it. I plan to free up the exhaust - I already have a 2.5" exhaust, no muffler, and now a WRX downpipe to install later.. and I've mentioned that I might make a header for it. I will also chop the airbox out after I take it through emissions soon. I don't want to up the boost because I am aware that you have to "pay to play" and I frankly don't want to pay. It'll be nice enough to drive after I put a 5-speed in it and get the turbo freed up! When my 86 wagon was still turboed, I had a 2.5" open exhaust with catless downpipe/divorced wastegate, and chopped airbox, and it was fast enough for me.. never headered that engine but I wanted to badly!
March 10, 200719 yr Author totally... I couldn't pass that one up! it was right after I'd gotten the car, too. Not yet installed.
March 10, 200719 yr People Have thrown the wrx turbo on the ea82t's. If they can do it why can't an ea81t hold it, thats my reasoning anyway.
March 10, 200719 yr Author I could, but parts for EA81Ts are much more rare, so I'm much more careful with it...
March 11, 200719 yr I'm no expert, but I don't think it would matter moving it to infront of the turbo. It does matter.... The sensor on the wrx will be designed to run at a lower exhaust temperature than yours - it may even be a 3 wire one? If you move the wrx one to the stock ea81t location, it will probably have a very short life. If you move the ea81t one to after the turbo, it may not work at all.
March 11, 200719 yr If you move the ea81t one to after the turbo, it may not work at all. I don't think this is the case. EA82T O2 sensors are after the turbo, not before it as with the EA81T. They're the same O2 sensors.
March 11, 200719 yr Author thanks guys. If they are the same O2 sensors between EA81T and EA82T, as I was about to wonder, then that says a lot to me.
March 11, 200719 yr I don't think this is the case. EA82T O2 sensors are after the turbo, not before it as with the EA81T. They're the same O2 sensors. Yeah, they are straight after the turbo though, right? bacc said that the wrx one was "somewhat downstream of the turbo", which i assumed meant a bit further down - i'm not familiar with turbo ejs at all. So yeah, if its straight after the turbo, should be fine.
March 12, 200719 yr Author i'll have to look at it again - I would definitely not want it to be like 2 feet after the turbo for instance...
March 12, 200719 yr It should not matter where the O2 sensor is as long as its before the cats. Who needs cats... Anyway the wrx has 1 o2 in the uppipe, before the pre-cat. EJ22t's are right directly behind the turbo in the down pipe, just a few inches past the turbo
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