mickeyw Posted October 11, 2010 Share Posted October 11, 2010 I'm going to be fitting RRC downpipes to my 3.9 engined Ninety. I'm just about to order the downpipes and Y piece, and have discovered there are different items for auto and manual gearbox versions. These will be non-cat pipes BTW. Who can tell me what the physical differences are, and why? TIA Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted October 11, 2010 Share Posted October 11, 2010 I'm not aware of any difference on the 3.9 whether it's auto or manual, so that's a new one on me! The 3.5EFi (manual) had a smaller diameter and was routed above a square section gearbox crossmember, this is straight at either end and protects the exhaust. The exhaust is straighter here but dips down behind the crossmemeber. The end of the downpipe and Y peice are different. On the 3.9 the pipe is bigger and is routed below a round tubular cross member that cranks up above the exhaust at either end. The cross member sits a bit higher but the exhaust is a bit more exposed. After I flattened mine I refitted the 3.5 crossmember and a sports exhaust (I found these are the same diameter on 3.5 & 3.9). AFAIK the 3.5 auto had the same arrangement, I'm not aware of any reason it wouldn't fit. Later 3.9 had cats in the downpipes but other than that they were the same as best I can tell. If you do learn there's a difference I'd love to know. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted October 13, 2010 Author Share Posted October 13, 2010 According to MCAT: NTC7320 - Non cat auto transmission NTC7321 - Non cat manual transmission Gawd knows what the actual difference is Most of the parts suppliers seem to stock both numbers, so I guess I'll have to ring and ask. Quote Link to comment Share on other sites More sharing options...
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