Bowie69 Posted September 9, 2015 Share Posted September 9, 2015 Tyre size may influence this decision, but with 265/75R16, and later 255/85R16 I found my 3.9 auto horrible to drive with a 1.2:1. Long hills were a struggle and needed a manual down shift, or flooring to make it kick down. I found on rural roads it never had a chance to lock up in top. Changing ratio to 1.4:1 totally transformed the drive. The forum ate a couple of my posts, but this is exactly my experience when I moved to 33", gearing was too tall, yes more revs at cruise, but that doesn't mean more fuel, actually Oh, and even with an auto I get the tyres chirping when hoofing it from a junction! Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 9, 2015 Author Share Posted September 9, 2015 Oh and can you reply to my previous post and let me know if your going to bid on the engine I linked to. Sorry - missed that... Go for it - upping the power is a long term plan, I have some other projects I have to get finished first!! Quote Link to comment Share on other sites More sharing options...
mickeyw Posted September 9, 2015 Share Posted September 9, 2015 Oh, and even with an auto I get the tyres chirping when hoofing it from a junction! Oh yes, quite easily done Quote Link to comment Share on other sites More sharing options...
need4speed Posted September 9, 2015 Share Posted September 9, 2015 Sorry - missed that... Go for it - upping the power is a long term plan, I have some other projects I have to get finished first!! No worries Jon. Thanks for letting me know Quote Link to comment Share on other sites More sharing options...
=jon= Posted September 9, 2015 Author Share Posted September 9, 2015 I've a turbocharged mazda mx5 that's been gathering dust after an engine rebuild for close to 2 years (runs but needs some rewiring, running in and remapping) - I think if I took another project on that required an engine rebuild/swap I would get some comments from the family!! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 15, 2015 Share Posted September 15, 2015 If I was going to continue to add mods to it then I would consider ms...... However the only thing that will happen when needed is a rebuild. .. thankfully I think its a while away from that yet.. I would re-look at MS - A chip gets you a generic tune for an engine somewhat like yours, MS gets tuned to your engine and vehicle (which does make a difference to how you tune it). Also does away with dizzy if you go EDIS which makes a BIG difference especially on LPG, the Rover/Lucas dizzy setup is weak at best. And you can transfer it to any future engine / vehicle with only a change of settings rather than having to buy another chip. Quote Link to comment Share on other sites More sharing options...
HoSS Posted September 17, 2015 Share Posted September 17, 2015 Hi Jon, The mixer ring does certainly restrict the flow a bit. There was a loss of power after fitting it. But as you say LPG saves the wallet and that was a compromise. I did consider a multipoint injection as an upgrade. IIRC the spare block has higher compression ratio, which was my other plan for a bit more power. Quote Link to comment Share on other sites More sharing options...
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