kevinr Posted November 5, 2008 Share Posted November 5, 2008 What would be the penalty/benefit of replacing my down pipe with a de-cat one? Aside from being significantly cheaper, and a little more engine noise, does my tax increase or anything like that? Quote Link to comment Share on other sites More sharing options...
nicedayforit Posted November 5, 2008 Share Posted November 5, 2008 What would be the penalty/benefit of replacing my down pipe with a de-cat one? Aside from being significantly cheaper, and a little more engine noise, does my tax increase or anything like that? I stand to be corrected on this but I don't think you can fit a de- cat pipe to a petrol V8, your're not likely to pass the Mot Emissions test. De-cat pipes are normally fitted to diesel engined cars where no emissions standards have to be met only a smoke test where a cat plays no part. On diesel cars the advantage is reduction in exhaust back pressure, there are no tax implications. Quote Link to comment Share on other sites More sharing options...
teabag Posted November 5, 2008 Share Posted November 5, 2008 Kevinr. You can fit a Y pipe without 'cats' to engine to increase the performance of the engine. The 3.9 engine ECU will have to be modified to take into account the changes as the exhaust with not have as much restriction and the lambda sensors will be missing. Will it past the MOT emmission test will depend on how good the engine tune has been done, you may have to reinstate the old Y pipe with the 'cats' just for the MOT test. If you are after increased performance then Janspeed Exhaust do a Y pipe fitted with de-restricted 'cats'. you can add the two tublar manifolds and also a sports mid and tail box to that if you wish. Your tax or any thing like that will not increase. Quote Link to comment Share on other sites More sharing options...
kevinr Posted November 5, 2008 Author Share Posted November 5, 2008 Thanks for the replies guys The reason I want the decat pipe is not performance related..though an increase would be a good bonus, the reason is I think mine is starting to blow..(it could just be a draft off the cooling fan, I've yet to fully check this out) and the cost of a decat is about 10 times cheaper then a catalysed downpipe..I think the decat is around £45 on paddocks..it's under the 3.9 EFI link, but described for a 3.5, I assume the pipe is the same and will fit either engine. To get the ECU modified, is this a dealer job, or could my local LR specialist auto electrician do it? Quote Link to comment Share on other sites More sharing options...
thebiglad Posted November 5, 2008 Share Posted November 5, 2008 I was under the impression that all petrolengined cars produced after a certain date, had to have cats, no question about it. I guess the question is - what's that date?? Sorry don't know for sure but I think it was 1998 ish???? Quote Link to comment Share on other sites More sharing options...
nicedayforit Posted November 5, 2008 Share Posted November 5, 2008 I was under the impression that all petrolengined cars produced after a certain date, had to have cats, no question about it.I guess the question is - what's that date?? Sorry don't know for sure but I think it was 1998 ish???? August 1 1992 Quote Link to comment Share on other sites More sharing options...
nicedayforit Posted November 5, 2008 Share Posted November 5, 2008 I was under the impression that all petrolengined cars produced after a certain date, had to have cats, no question about it.I guess the question is - what's that date?? Sorry don't know for sure but I think it was 1998 ish???? August 1 1992 Quote Link to comment Share on other sites More sharing options...
teabag Posted November 6, 2008 Share Posted November 6, 2008 The only information about the MOT and catalyst converter I have been able to find, is of the date from which a cat test should be carried out on a vehicle and nothing on the fitment of a cat to a vehicle. ie. "The catalyst test is part of the MOT test for most class IV spark ignition petrol engined passenger cars with four or more wheels first used on and after 1 August 1992". Copied from this site http://www.motuk.co.uk/manual_730.htm Just as nicedayforit said. Quote Link to comment Share on other sites More sharing options...
teabag Posted November 6, 2008 Share Posted November 6, 2008 Thanks for the replies guys The reason I want the decat pipe is not performance related..though an increase would be a good bonus, the reason is I think mine is starting to blow..(it could just be a draft off the cooling fan, I've yet to fully check this out) and the cost of a decat is about 10 times cheaper then a catalysed downpipe..I think the decat is around £45 on paddocks..it's under the 3.9 EFI link, but described for a 3.5, I assume the pipe is the same and will fit either engine. To get the ECU modified, is this a dealer job, or could my local LR specialist auto electrician do it? This issue is running on this forum http://forum.landrovernet.com/showthread.php?t=137332 Quote Link to comment Share on other sites More sharing options...
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