Steviekid Posted March 22, 2006 Share Posted March 22, 2006 Quick question. I know the UK spec has two lambda sensors but does it have the temperature sensor as well like in the J-spec? Quote Link to comment Share on other sites More sharing options...
Steviekid Posted March 22, 2006 Author Share Posted March 22, 2006 Also does the Jap NA have one lambda and the temp sensor or two lambdas? Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 22, 2006 Share Posted March 22, 2006 .. I know the UK spec has two lambda sensors... You know more than I do then. Keep the info coming... Quote Link to comment Share on other sites More sharing options...
Steviekid Posted March 22, 2006 Author Share Posted March 22, 2006 You know more than I do then. Keep the info coming... I take it that's wrong then! I was under the impression the UK and US spec has a second lambda sensor in the second cat pipe? http:// Quote Link to comment Share on other sites More sharing options...
DannoSupra Posted March 22, 2006 Share Posted March 22, 2006 Yeah mine was in my second Cat, Now just in a pipe, NO 2nd CAT, is it ok to remove the 1st one? Quote Link to comment Share on other sites More sharing options...
Steviekid Posted March 22, 2006 Author Share Posted March 22, 2006 Edited because it was wrong! I'm confusing myself now!!! Quote Link to comment Share on other sites More sharing options...
Burna Posted March 22, 2006 Share Posted March 22, 2006 I've been told there's 2 also One in the downpipe before the first cat then one in the second cat, hence the second decat pipes for the UK are different, I could be way off here though Edited because I founds these two posts: Post #17 http://www.mkivsupra.net/vbb/showthread.php?t=57957&page=2&highlight=sensor Post #7 http://www.mkivsupra.net/vbb/showthread.php?t=61821&highlight=decat Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 23, 2006 Share Posted March 23, 2006 UKSpec and USSpec are *close* but not identical. There are even variations among USSpecs. Quote Link to comment Share on other sites More sharing options...
Burna Posted March 23, 2006 Share Posted March 23, 2006 So is it two or not John, throw us a bone please mate Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 23, 2006 Share Posted March 23, 2006 But you've already highlighted yourself! Quote Link to comment Share on other sites More sharing options...
Burna Posted March 23, 2006 Share Posted March 23, 2006 I give up lol Quote Link to comment Share on other sites More sharing options...
Keith C Posted March 23, 2006 Share Posted March 23, 2006 There are TWO O2 sensors on the UK-spec. There is NO Cat temperature sensor on the UK-spec. I don't know about the NA, but I would be very surprised if it had a 2nd O2 sensor. Quote Link to comment Share on other sites More sharing options...
Burna Posted March 23, 2006 Share Posted March 23, 2006 Cheers Keith I've only ordered the one of Nic Quote Link to comment Share on other sites More sharing options...
Keith C Posted March 23, 2006 Share Posted March 23, 2006 Ah, well, I have no idea if they're the *same* as each other, just that there are two... Quote Link to comment Share on other sites More sharing options...
Sharpie Posted March 23, 2006 Share Posted March 23, 2006 There are TWO O2 sensors on the UK-spec. and here they are: Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 23, 2006 Share Posted March 23, 2006 They are not 2 oxygen sensors in the way that they are in a V8 (one per bank), or a Skyline (one for every three cylinders). In these versions of the supra only one oxygen sensor is used by the ECU to cover all cylinders. If you find evidence that the output of the second one is used in any meaningful way I'd be quite interested. California versions for example use it to compare the mixture and ensure that the cats do their stuff. Here if you stick a decat it doesn't blink - no ECU errors, nothing. Quote Link to comment Share on other sites More sharing options...
Keith C Posted March 23, 2006 Share Posted March 23, 2006 No, I think that much is apparent from the second one being half way down the car It definitely serves some purpose though (I forget what) - it's definitely better to have it in the exhaust flow than not, which is why Chris' decat pipes for UK-specs cater for it. Edit: Ah, here's one thread talking about it: http://www.mkivsupra.net/vbb/showthread.php?t=51897&highlight=sensor Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 23, 2006 Share Posted March 23, 2006 I remember from people who had it hanging out in the open and then stuck it back in the exh flow that they felt there was no difference whatsoever (apart from the whole setup being more tidy of course) I treat it like a half-way house to the USSpec, same as EGR. In the USSpec there is also a sensor for the ECU to know if the EGR is indeed operational. If not, the ECU throws an error and uses a different ignition/fuel map. The UKSpec hasn't got that level of functionality. Quote Link to comment Share on other sites More sharing options...
Keith C Posted March 23, 2006 Share Posted March 23, 2006 Dunno - here's another one talking about it: http://www.mkivsupra.net/vbb/showthread.php?t=32577 Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 23, 2006 Share Posted March 23, 2006 Nice thread that one. Thankfully there are dyno graphs from the same operator, so we can make comparisons. What strikes me is that they didn't pick up the reason they 'lost' the handful of lbfts (347 vs 354) If you look closely you'll see that after the partial decat it was running 0.4 - 0.5 AFR richer. So it's no wonder it lost some torque (it was richer towards the wrong side of the max torque AFR) That is roughly what gains you see as get as you go leaner under boost --- the closer to 13:1 the more power you pick up. Now it takes nerves of steel to keep it at 13:1 under boost on purpose , so 12.5 is a safer level to aspire to (if you have lots of confidence into your intercooling and fuel quality). If not, 12:1 is safer yet and if you're not feeling lucky and use shite fuel then 11:1 gets you home. But as you distance yourself from 13:1 you lose horses, that's how it works. I gained 20bhp at 0.9bar just by leaning 2 AFR points (10.5 ---> 12.5) As for the second sensor I've had it on and off, no difference whatsoever. The wideband shows that the ECU doesn't behave any differently because of it. If anyone has any evidence to the contrary, let's look deeper. Quote Link to comment Share on other sites More sharing options...
Burna Posted March 23, 2006 Share Posted March 23, 2006 Thanks Keith and thanks John, I'm not going to bother replacing both O2 sensors after reading the info you both posted up. I'll put the new sensor in the downpipe, it seems that's the place where it will give the best benefit. Quote Link to comment Share on other sites More sharing options...
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