Dunc Posted November 26, 2010 Share Posted November 26, 2010 Hi everyone, Bit of a strange query, but i guess that's part of my raison d'etre! I'm replacing the exhaust on my 1985 2-door RRC, nothing revolutionary there i know, but i don't want to replace it with the twin pipe system it has as standard. The downpipes from the manifold, NRC4219 and NRC4220, seem to be identical for all RRC's to 1985 as does the 'Y' pipe, NRC4218. The differences at the supplier seem to be the centre silencer which joins to the 'Y' pipe and comes in single or twin pipe outlet, 594973 & NRC1973 respectively. What i'm after doing is fitting a single pipe outlet silencer rather than the twin pipe version. This will facilitate me putting my own rear pipe and back box on. Like i said, not the most radical of problems, but it will just save me wasting money (which is currently at a premium) buying bits that wont fit. I know i could cut and reweld everything, but i'm after a much easier solution with an amalgam of standard parts to make future replacement easier; one off bits always fail at the most inopportune of moments! So, is there any other difference in the single outlet exhaust intermediate silencer and the twin outlet intermediate silencer other than the outlet pipes? Cheers. Quote Link to comment Share on other sites More sharing options...
SteveRK Posted November 26, 2010 Share Posted November 26, 2010 Try this link to the Bosal web site: http://www.catalogue.bosal.com/pages/exh_cartype_search.php It doesn't give dimensions but if you search you will see that from 1985 they reverted to single pipe after the middle silencer/resonator box. The 3.9 bore diameter output is larger than for the dual output but I couldn't say whether the down pipe to middle silencer bore is larger. Quote Link to comment Share on other sites More sharing options...
Dengie Boy Posted November 26, 2010 Share Posted November 26, 2010 So, is there any other difference in the single outlet exhaust intermediate silencer and the twin outlet intermediate silencer other than the outlet pipes? Mines an 87 that has the single pipe from the Y piece right through to the rear silencer but then exits with twin tailpipes. Think this system was fitted from 86 to 89 on the 3.5efi then they had a single exit tailpipe on the 3.9efi. I know these two systems are different in size as the later one has a larger diameter, hope that info will help you. Cant help you on the earlier twin system im afraid. Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted November 27, 2010 Share Posted November 27, 2010 The 3.9 system is also routed differently around the gearbox crossmember from what I've experienced. I'm not really sure about the twin pipe systems but I thought they were discontinued when the 3.5 EFi was introduced. I'm told they sound different. Logic suggests that the EFi systems were the more efficient. Quote Link to comment Share on other sites More sharing options...
Dunc Posted November 27, 2010 Author Share Posted November 27, 2010 Thanks for the comments. Ideally, i'm after the comparison of the pre-'83 single outlet intermediate box and the subsequent twin outlet intermediate box. My old 3.9 was a single and was very different around the gearbox, especially where the cats were! I'll see if i can glean any clues from the Bosal link, although as i've now found the centre boxes for £16 + vat i may just give it a whirl and see! Cheers. Quote Link to comment Share on other sites More sharing options...
disco_al Posted November 27, 2010 Share Posted November 27, 2010 the 3.5 efi disco that i had was fitted with a single pipe system. two downpipes, into the y section, than back to the rear through a centre silencer. Quote Link to comment Share on other sites More sharing options...
disco_al Posted November 27, 2010 Share Posted November 27, 2010 this was the disco system size wise, the book gives (for the carb 3.5) downpipe 45mm internal to y section 44.5mm external middle box outlet 56.5mm internal to rear pipe 56mm external Quote Link to comment Share on other sites More sharing options...
fozsug Posted November 27, 2010 Share Posted November 27, 2010 Or you could use NTC2802 down pipe rh NTC3226 down pipe lh NTC4061 intermiate pipe (y piece) NTC1322 centre silencer NRC9836 rear silence assembly Single pipe all the way, two pipes out of the rear silencer Quote Link to comment Share on other sites More sharing options...
Dunc Posted November 27, 2010 Author Share Posted November 27, 2010 this was the disco system size wise, the book gives (for the carb 3.5) downpipe 45mm internal to y section 44.5mm external middle box outlet 56.5mm internal to rear pipe 56mm external 56mm external, should be the same one the Rangey one i'd have thought. Thanks Al. Or you could use NTC2802 down pipe rh NTC3226 down pipe lh NTC4061 intermiate pipe (y piece) NTC1322 centre silencer NRC9836 rear silence assembly Single pipe all the way, two pipes out of the rear silencer If google is right then those part numbers are for the model years after mine, but pre-cat. The downpipes still look the same. They're the corresponding RRC part numbers to the Disco system Al posted... Thanks very much guys, i'm obliged. So, this is what should go on mine and from your help hopefully this, minus the back box, is what will go on mine Crossing everything! Quote Link to comment Share on other sites More sharing options...
fozsug Posted November 27, 2010 Share Posted November 27, 2010 Good luck.....just keep youre recipt just in case Quote Link to comment Share on other sites More sharing options...
Dunc Posted November 28, 2010 Author Share Posted November 28, 2010 All ordered and on its way. Ended up getting it from Paddocks in the end, free shipping as compared to Rimmer Bros. May have to find the odd gasket and clamp on eBay, but hey ho. Quote Link to comment Share on other sites More sharing options...
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