Orange Posted June 21, 2007 Share Posted June 21, 2007 I've been having a read of Les' TechArchive write-up on the fitting of a GKN overdrive to a 300TDi Defender (here) and it got me wondering about fitting one to a manual D2. I've had a quick scout around, but can't find anything about this variation of fitment and was wondering if anyone has done it or knows of it being done?? The main aims, as with all vehicles fitted with overdrives, would be to lower the cruising RPM, increasing the fuel economy and also lessen the engine noise when cruising at motorway speeds. This is the one thing that bugs me about the Disco and it would be nice to find a way of sorting it other than fiting a 6 speed box out of a new Defender... Any views or experiences?? TIA Adrian Quote Link to comment Share on other sites More sharing options...
BogMonster Posted June 21, 2007 Share Posted June 21, 2007 I guess you can but I don't know how much it would gear up the vehicle bearing in mind the Discovery tbox is already about 20% higher than the Defender one (1.22 compared to 1.41) if you increased the gearing by a further 15-20% or whatever your chosen overdrive increases it by, it might be just too much and render top gear a waste of time? What revs does the Td5 Discovery cruise at, at say 70mph? Quote Link to comment Share on other sites More sharing options...
Orange Posted June 21, 2007 Author Share Posted June 21, 2007 I can't say for sure, but it's about 2800 to 2900..... I'm off out in a little while, so I'll check and get back! The main point is the noise that it generates makes it sound like it's doing a lot more!! Getting the noise reduced would make it a much better motorway cruiser! Quote Link to comment Share on other sites More sharing options...
Mark Posted June 21, 2007 Share Posted June 21, 2007 Maybe a soundproofing kit would be a better option?? Quote Link to comment Share on other sites More sharing options...
Orange Posted June 21, 2007 Author Share Posted June 21, 2007 I'd like to also improve the mpg as well, though!! Yes the soundproofing kit would be the cheaper option, but it only attacks one element of the problem..... If there's a way to hit all 3 nails on the head with one hammer, surely it's better to go down that route?? Quote Link to comment Share on other sites More sharing options...
jericho Posted June 21, 2007 Share Posted June 21, 2007 I drove a td5 90 with a gkn overdrive the other day and thought it was great - a much calmer experience at crusing speeds,but you already have higher gearing, so I can't really say anything to help! Quote Link to comment Share on other sites More sharing options...
JST Posted June 21, 2007 Share Posted June 21, 2007 my old mans D2 td5 with 1.2 box only does 200/300rpm more than my td5 90 1.4box with an overdrive in respective top gears at 70mph. i think it would be too high to be of much use unless you do alot of fast a roads. you would prob also want to chip it to make the most use of the taller gearing i would have thought. Quote Link to comment Share on other sites More sharing options...
ashtrans Posted June 21, 2007 Share Posted June 21, 2007 Hi, I don't think the disco will pull it, the 1.2 is 15% higher than the 1.4 already and the GKN OD is an additional 27%, that's quite a lot even if you chip it, if you do it you will need the 38 tooth version not the normal 26 tooth one and I think you will also need to chop some bodywork from the rear footwell to fit, Quote Link to comment Share on other sites More sharing options...
JST Posted June 21, 2007 Share Posted June 21, 2007 Well ^^^^^ i would say the man knows has spoken, and would take Daves. Quote Link to comment Share on other sites More sharing options...
Orange Posted June 21, 2007 Author Share Posted June 21, 2007 I was kind of hoping that Dave would come along and offer some advice - I saw him lurking inthe background earlier.... Top gear is pulling between 2750 and 2800 rpm at 70 and is a bit clattery. Think I might investigate the sound proofing, afterall!! Pesky older brothers!!! Cheers for the input guys.... Quote Link to comment Share on other sites More sharing options...
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