Thread: Series 3 Engine swap, 300tdi vs 3.9

Hi,


I'm sure you are in the right place to ask this question, and I'm sure the diesel v petrol debate is thoroughly covered throughout the forum.


I've run dual fuel LPG-Petrol vehicles for the past 25 years without any reliability issues and appreciated the cost savings of LPG. Having an LPG tank on-board offers extended kilometres between fuel stops; but in the bush this is still not up to the economy benefits diesel offers. Must admit I've travelled a lot of out of the way places without having to drown my 4WD. A bit of wading here and there and never had a petrol engine die on me mid-stream. A matter of careful driving and sealing up the electrics I guess!?


Personally I'd be leaning towards a diesel option but investigate adding LPG injection for those wonderful 25-30% performance gains claimed. Yes, a significant extra cost, but maybe worth looking into?


I look forward to what more experienced contributors thoughts are.


Cheers

Originally Posted by shiftybigmac

Afternoon boys, over the Christmas break im looking to start a new project using a series 3 4 door wagon and a automatic D1 disco (1994- 1998) because leaf springs are awesome and old trucks deserve a second chance. I plan to buy a fully running and good mechanical disco ether 300tdi or 3.9 V8 and swap over the axles and running gear using custom mounts and new props...ect. My dilemma is that as a hunting and expedition rig heading well out into the sticks I am trying to remove all electrics and would prefer to be installing mechanical everything to increase reliability. I will also be very heavily laden (call it high at~350kg) with guns, people, PTO winch (im serious about this electrics thing), petrol chainsaw, various hand tools, 3 spare tires and all other sorts. I am being lead to believe that the 300tdi is better reliability wise however will a Holly truck carb on the 3.9 equal the same reliability? (I will not be bringing a ECU diagnostic computer with me as some have suggested previously). Overall currently im leaning towards the diesel as I know the 300 excels in deep water crossings (above bonnet) as a true mechanical engine but how bad realistically is the 3.9 underwater (can I properly waterproof dizzie and coil?) and how much down is the tdi on power considering the fully laden weight (do I put myself at a off-road disadvantage power and torque wise compared to the V8?). Finally how badly does the 3.9 lag in the fuel economy department both off-road and on road surfaces as fuel range is a serious issue and would just prefer to not spend my lifesavings on the octane. Cheers guys

I've got both 3.9 and 300tdi, the v8 is parked up as a spares car.


IMO the tdi is down on power in stock tune however with a few parts that every tdi owner should get and a fuel tune you will be miles in front with the diesel.
The v8 is a thirsty beast in the bush I cant comment on LPG mpg as I like the power petrol gives.


Don't forget that when your right out in the sticks Diesel is everywhere farmers use heaps and mine sites use heaps as well, they will part with a few jerry cans but may not want to part with very much petrol.