Thread: Petrol VS diesel?

I compare my much modified 3.9 V8RRC and my td5 D2. My 3.9 put out about 50% more torque than a stock 3.9 from 1500 tapering to 3000 where it was about 20-25%.

The D2 tows much better than the RRC.There is a BIG hill just North of Buladelah going South. In my RRC I would hit the bottom at 120Kmh and be doing 80 at the top and dropped out of TC lock or in 3rd towing my 900KG Camper trailer.
My TD5 hits the bottom at 120 and is doing 115-120 at the top in top locked. My TD5 is also modded with 22lb boost, big intercooler, map, ETC ETC.

True I could floor the RRC and drop down to 3rd and maybe do 100 at the top, but at what cost. The fuel economy would be horrendous.
It is also true that once you lose speed with a diesel it is very hard to accelerate up a hill while towing, the torque will carry you up, but you do not have the revs like in a V8 to accelerate .

The only time I really miss the v8 is when some dork stops me hitting the bottom of the hill at optimum speed and I am then stuck behind them and have to hit the left lane behind whatever it is that the baulker has passed.
Regards PhilipA

I think there are pros and cons of both types of engines - all depends on what suits you best but there is no right or wrong.

I had always been a petrol driver and in 2004 bought my first diesel - a 98 Freelander L series - with on 72kw not a power house. When I bought it I owned a 3.9 Disco 1 V8 and drove it with a friend to pick up the Freelander. On the way back home I drove the Disco and my mate drove the Freelander - going up the hills I was not able to keep up with the Freelander - it was demonstrating its better lugging power compared to the Disco.

I kept both vehicles at the same time for about 4 years so was able to compare the two in similar circumstances - the Freelander was a leisurely drive but always had good pulling power compared to the V8 which cruised really well. The V8 never pulled will up hill offroad at low revs in high range - but of course there was always low range - the Freelander was able to pull hills that the Disco could not pull in 1st high range.

I then sold the Disco and later bought the RRS - driving it back from Melbourne the first thing that struck me was how similar the RRS and the D1 V8 was on the road - the engines produced similar power and the TDV6 a little more torque - offroad the TDV6 was like all diesels just pulls and on the highway is like the V8.

Now my 101, V8 producing 22l/100km in most circumstances except sand (35-40l/100km) but 4wd otherwise the same as on the road - so different vehicles work differently.

One engine is not better than the other - they are different.

For me - on the highway, a high speed modern diesel or a modern petrol. Offroad, light work either, heavy work then a diesel - sand a diesel. Towing heavy stuff I would have thought a diesel but my brothers 200 series TDV8 struggles and gets 22l/100km but other brothers 2 litre HiLux get similar consumption to my RRS at around 13-15l/100km. Petrol can do it too but weight can be less comfortable but more importantly driving smoothly with little throttle changes makes a bit difference.

Drive what you are comfortable with.

Garry

I went from a 6.0L petrol V8 Commodore SS to a D4 TDV6.

I luv the D4. It may not accelerate quite like the SS, which is mind boggling - but it gets up and goes nicely. I never towed my current 6.5M/2500 kg boat with the SS, but the D4 tows it like its not there.

The SS did about 9L/100km cruising on the highway (by dropping back to 4 cylinders), while the D4 does about 10L/100km.

The D4 does about 17L/100km towing the boat at 110km/hr, while the SS did 99.9L/100km off the lights!

Originally Posted by ozscott

Admittedly I.skipped through it but the petrol.was loaded up foot to the boards holding just under 6000rpm. Most post was ambiguous but I mean the petrol.wont like nor last doing that regularly. Cheers

i dunno,. mine spend a lot of time near redline

want torque? diesel
want power? small petrol with turbo
want power & torque? big petrol like a v8


towing a semi only requires torque, not power, hence diesel

simple?

Simply - you need something Fit for purpose.

Our new Defender is Turbo Petrol (fun)
The D4 does most of the mule work (towing)

My work vehicles are different - no Flammables allowed so diesels only.

Originally Posted by Eevo

want torque? diesel
want power? small petrol with turbo
want power & torque? big petrol like a v8


towing a semi only requires torque, not power, hence diesel

simple?

Torque is the capacity to do work.

Horsepower introduces a time element. Horsepower is work done in time taken.

Want power and torque? Then a big diesel like a Cummins or Detroit is the solution.

Big petrol engines (up to 12 litres) had their day in trucks when gasoline prices in the USA were 20c. per gallon. They were cheaper to buy and fuel economy did not matter. Operators could wear one out and rebuild it twice for the price premium of a big diesel. OPEC fixed this idea up in 1974 with the first oil shock.

For those unfamiliar with diesel operation the operating range of a diesel engine is the rev. band between governed rpm and maximum torque. Ideally gearbox ratios would be arranged so that on reaching governed rpm and upshifting the next gear would pick up at maximum torque. Reverse this for downshifts.