P-unit Posted October 26, 2017 Report Share Posted October 26, 2017 Hello Chaps, long time lurker, first time poster. I'm in the process of sourcing a new exhaust system for my 2003 2.7 986. Last week the check engine light came on, faults were read and showed 02 sensors on bank 1-3 were gone and 4-6 were on the way out. I'm guessing i'll probably break the 02 sensors getting them out so i'd basically planned on getting a complete new exhaust, which i'd planned on doing at some point anyways I've seen several exhaust systems on ebay, most showing straight pipe where the cats would originally be, is anyone running this set up and have they had any issues passing MOT's or setting the check engine lights? I'm not looking to do a re-map. The set up i was looking at is something like the link below https://www.ebay.co.uk/itm/Porsche-986-Boxster-S-2-5-2-7-3-2-Stainless-Manual-Exhaust-System-1997-to-2004/382171162736?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 I'm sure someone's answered this question before but i cant seem to find a thread explaining it. Any advice would be appreciated. Link to comment Share on other sites More sharing options...
edc Posted October 26, 2017 Report Share Posted October 26, 2017 I highly doubt you will pass the MOT emissions. I've had those manifolds on both my Boxsters and with 100 cell cats on their last legs it didn't pass. Link to comment Share on other sites More sharing options...
mikefocke Posted October 27, 2017 Report Share Posted October 27, 2017 O2 sensors can be removed by any muffler/exhaust shop using a special tool or you can buy one. Mine were about 10 years old when replaced and it took more time from the exhaust and cats to cool down than it did to replace each. They were done years and many miles apart by different shops. Bosch makes em for Porsche. more info here. Link to comment Share on other sites More sharing options...
Jason986S Posted October 27, 2017 Report Share Posted October 27, 2017 You wont pass an mot without cats. Probably fail for just not having them fitted, let alone the sky high emissions results. Mine failed with sports cats fitted too. The post cat lambda doesnt overly do a lot and in my experience doesnt even need to be plugged it and it doesnt through up a check engine light. I now run a full stainless exhaust. BlueFlame manifolds (same as ToyoSport eBay ones), Dansk sports cats (hollowed out to decat) and a Janspeed rear box and the joining U pipes. It doesnt crackle and pop too much, but it sure does wail up in the revs and can chuck a little flame when you let off at high revs. I cant imagine driving a 986 with a stock exhaust now, would be quite numb and unsensory. Link to comment Share on other sites More sharing options...
P-unit Posted October 27, 2017 Author Report Share Posted October 27, 2017 Ok thanks guys, cats it is then! Link to comment Share on other sites More sharing options...
the baron Posted October 28, 2017 Report Share Posted October 28, 2017 You can go catless, but just have a set to put back in place when you MOT it, as others said there is no way it will pass without. Link to comment Share on other sites More sharing options...
ooid Posted November 1, 2017 Report Share Posted November 1, 2017 I have used these for my exhaust system on my old 986 boxster (2.7, 2000) - react catalytic converter(s) - Eurocarparts - 2 new lambda sensors - FAE Brand (They are basically spanish bosch, and half price lol) - The OEM muffler, just a bit of fixing it was all good. It passed MOTS twice, no issue with the emissions.. the whole set-up cost was less than 500 GBP, If I remember correctly (labour included) Link to comment Share on other sites More sharing options...
That986 Posted November 2, 2017 Report Share Posted November 2, 2017 The problem you will have if you decat a later 986 is the secondary O2 sensors, they will read off the charts and affect the engine fueling if you decat. Unless you can get round that (via mapping etc) then there really would be no point. I've decatted mine (2000S), have no problems with engine lights etc and i get to hear that glorious noise a lot more but i have only have one set of sensors which are pre-cat. As for the MOT the others are correct with what they say about not passing, you'll have to swap it back out or find a friendly MOT tester. Link to comment Share on other sites More sharing options...
edc Posted November 2, 2017 Report Share Posted November 2, 2017 2 hours ago, That986 said: The problem you will have if you decat a later 986 is the secondary O2 sensors, they will read off the charts and affect the engine fueling if you decat. Unless you can get round that (via mapping etc) then there really would be no point. I've decatted mine (2000S), have no problems with engine lights etc and i get to hear that glorious noise a lot more but i have only have one set of sensors which are pre-cat. As for the MOT the others are correct with what they say about not passing, you'll have to swap it back out or find a friendly MOT tester. The rear 02 sensor issue came up some while back. I don't think they do anything to the fueling as such. Mine were on most of the time with the 100cell cats and the mpg was normal and it passed MOTs with the CEL on. Link to comment Share on other sites More sharing options...
That986 Posted November 2, 2017 Report Share Posted November 2, 2017 6 minutes ago, edc said: The rear 02 sensor issue came up some while back. I don't think they do anything to the fueling as such. Mine were on most of the time with the 100cell cats and the mpg was normal and it passed MOTs with the CEL on. I'd love to see the evidence on that one or why would they be there in the first place? They can't be there just to measure the efficiency of the cats? Link to comment Share on other sites More sharing options...
Skidd Posted November 2, 2017 Report Share Posted November 2, 2017 FYI you can buy the sensors from euro car parts. Bosche part as said and they even have the porsche part number on them, except <1/2 the price. Flare-nut wrench is the tool you need. Mine for a 987 - £176 from OPC, or £77 ECP. Link to comment Share on other sites More sharing options...
P-unit Posted November 28, 2017 Author Report Share Posted November 28, 2017 All the parts have arrived, work starts on thursday! Link to comment Share on other sites More sharing options...
P-unit Posted November 28, 2017 Author Report Share Posted November 28, 2017 Should have asked this earlier on in the thread, other than the O2 sensor removal tool is there any specific tools that are required to swap the exhaust/remover the rear bumper, and help would be greatly appreciated. Thanks! Link to comment Share on other sites More sharing options...
Anker BS Posted November 29, 2017 Report Share Posted November 29, 2017 Band aids for your knuckles. Rusted exhaust bolts do that! Link to comment Share on other sites More sharing options...
mxm1275 Posted November 29, 2017 Report Share Posted November 29, 2017 Just to add: As someone who's just replaced the rear silencer on a late 986 2.7 (Sept'03 car/ 04MY) a point to note. The cat pipes are slightly different on the these cars, when compared to earlier cars. I was caught out as the brackets that support the rear silencer/s are in a slightly different place. Link to comment Share on other sites More sharing options...
P-unit Posted November 30, 2017 Author Report Share Posted November 30, 2017 What a day! This job is way tougher than I thought it would be, and I thought it would be tough! Started at the back, bumper off without too many issues, started with sockets and spanners, ended with hammers and grinders! After much cursing I got the back box off, time to look at getting the Cats removed from the manifolds; couldn’t budge them, man those studs are tough! Fair enough me thinks, I’ll drop the manifolds with the cats attached from the head and attack them on the bench.....managed to get three manifold bolts loose before, you guessed it, snap!!!! Bugger!!! So now I’ve got the back box off, can’t remove the cats and a snapped manifold bolt. Thought I’d try the O2 sensors, nope! Wrong part supplied, oval peg, rectangular hole. Managed to get the back box fitted (although the aftermarket clamps I bought are too big) and the car drivable to get home (in the snow to boot!). Hell of a day, many scraped knuckles!!! Bit of head scratching and a couple beers tonight to figure out what to do next. It’s a good job I love my porker! Any suggestions, lol? Link to comment Share on other sites More sharing options...
P-unit Posted November 30, 2017 Author Report Share Posted November 30, 2017 On 29/11/2017 at 12:30 PM, mxm1275 said: Just to add: As someone who's just replaced the rear silencer on a late 986 2.7 (Sept'03 car/ 04MY) a point to note. The cat pipes are slightly different on the these cars, when compared to earlier cars. I was caught out as the brackets that support the rear silencer/s are in a slightly different place. Yeah I had some issues with the pipes clamps and brackets, managed to ‘solve’ the clamp and pipe problem, and luckily I was able to apply some heat to the brackets and bend them into place. Link to comment Share on other sites More sharing options...
mike nixon Posted December 1, 2017 Report Share Posted December 1, 2017 We don't have mot here or what ever, but if you straight pipe with out re-mapping the fuel and some air box mods all i can see is loss of power. Link to comment Share on other sites More sharing options...
Jason986S Posted December 1, 2017 Report Share Posted December 1, 2017 23 minutes ago, mike nixon said: We don't have mot here or what ever, but if you straight pipe with out re-mapping the fuel and some air box mods all i can see is loss of power. Im not sure there would be a notable loss, especially as most stock items are known for causing a restriction, with a MAF/Lambda being able to adjust and compensate the AFR’s that may change. Link to comment Share on other sites More sharing options...
mxm1275 Posted December 4, 2017 Report Share Posted December 4, 2017 On 01/12/2017 at 2:45 PM, mike nixon said: We don't have mot here or what ever, but if you straight pipe with out re-mapping the fuel and some air box mods all i can see is loss of power. Agreed, unless the CATs have Lambda point, there will be issues. The car's brain still needs the information from the sensors. Link to comment Share on other sites More sharing options...
That986 Posted December 5, 2017 Report Share Posted December 5, 2017 On 01/12/2017 at 2:45 PM, mike nixon said: We don't have mot here or what ever, but if you straight pipe with out re-mapping the fuel and some air box mods all i can see is loss of power. Depends on how many sensors you have. If you just have the 2 pre-cat as in earlier models all you are doing is de-restricting the flow of gases which is always a good thing, as long as you keep the pipework the same size. If you have the 2 sets of sensors then you will need to do jiggery-pokery in the re-mapping department to either code them out or bring the parameters into spec, if those sensors detect unburnt fuel going through then it will start to change the fueling to compensate and/or throw the CEL. Link to comment Share on other sites More sharing options...
Patt Posted December 5, 2017 Report Share Posted December 5, 2017 On 02/11/2017 at 10:26 AM, That986 said: I'd love to see the evidence on that one or why would they be there in the first place? They can't be there just to measure the efficiency of the cats? Yep Mark Shead had de-cat and just disconnected the sensors for no ECL. Molly was forever throwing a light for post cat sensors - no issues wuith running or even passing an MOT in said condition. I just never got the energy to remove the rear bumper to get to the connectors on Molly. Alternative is Eporsch, as part of their re-map can remove the two sensors at the same time....but you still won't pass an MOT without fitting Cats for the test. Link to comment Share on other sites More sharing options...
That986 Posted December 5, 2017 Report Share Posted December 5, 2017 1 hour ago, Patt said: .but you still won't pass an MOT without fitting Cats for the test. Crux of the problem really. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.