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Diesel Engines What makes a good diesel alternative in terms of performance and power?

R

reb78

Trekker
I have been pondering this question for a while. I run my land rover 200tdi on Diesel or sunflower oil or rapeseed oil - often a mix of some/all. The engine is in good condition, the injection pump was reconned a year ago and the injectors not long before.

My feeling is that once warm, it runs best on
1. Rapeseed oil
followed by
2. Diesel with a sunflower/rapeseed mix (30-50%)
followed by
3. sunflower/diesel

Rapeseed oil makes the engine 'feel' more powerful and pull better with the others in the order above. Is it just anecdotal or is there any science behind it?
 
While I would agree with you rapeseed oil felt best I don't normaly use veg oil of any type last time I used any was during the fule strike 20 years ago.

For anyone who runs veg oil doing it on the cheap without the full kit to purge with deisel have a look at what Mike has to say over at Britannica Restoration


John
 
Due to a dispute with local recycling centre I put 20 litres of used engine oil through my astra. (IDI diesel lucas CAV dpc pump) I gravity filtered it through a lashup of coffee filters and strong magnet, thinned it with a dash of petrol, 50:50 with pump diesel

Smelt like a chip shop and a bit smokey at cold starts, but otherwise no noticeable difference in performance.

Like that video though, I think it's a gamble with the unknown
 
My ‘unknown gamble’ has been going well for about 8 years over approx 80k miles. Head off last year to change a head gasket and the bores looked perfect. Fuel pump rebuilt 18months ago as preventative maintenance and it was all good inside. I use new veg oul for long journeys in warmer weather and taper the concentration off as the weather cools to nothing in the winter. As long as you are careful and only do it in a suitable vehicle (i only do it in the tdi with the bosch VE pump) then you will be fine.

I have the kit to do a dual tank system but have not seen the need to fit it to date.

So why is there a noticeable difference between products?
 
scientifically speaking running straight rapeseed or sunflower it will effect performance negatively, it cant not. (eh?) veg oils have lower cetane value, which means it has more ignition delay (flame front takes longer to propagate) in time critical environment like diesel cycle is a real killer. they also have less energy density, for example sunflower oil is 17,000 btu/lb, diesel is 19,000 btu/lb. (really struggling to find data for rapeseed specifically, help! but all of the bio diesels are around that 17k mark)

there could be some anecdotal why it feels better, with less performance. like nuances with pump timing and turbo boost or just the fact its quieter and smoother and a bit of confirmation bias.
 
That's interesting Darren. I think you may have something with it being quieter. MPG and performance never seem negatively affected by using the SVOs though, unless I run them when it is too cold and then you notice you have overdone the veg.

Like I say, I have been running on up to 100% in the summer and have done thousands of miles like this - motorway cruising at 70+ is no problem, neither is towing a laden trailer.
 
DarrenH said:
veg oils have lower cetane value, which means it has more ignition delay (flame front takes longer to propagate) in time critical environment like diesel cycle is a real killer.
Click to expand...

Im sure this would be a serious consideration at LeMans... Im wondering how much effect this has on relatively slow revving engines like ours... :)
 
Quiet section of the forum, but will weigh in with my experiences on SVO. Rapeseed & Sunflower both have a definite but very slight loss in performance in our Xantia 1.9D (non turbo) also using the VE pump but the engine runs smoother and quieter also. Presumably due to the lower cetane being equivalent to slightly backing off the timing, also when cold the idle speed is about 150-200rpm lower than straight dino diesel. The only issues we've seen on these engines being an IDI is this (a non issue anyway when the car's already slow!) and the hardening of rubber pump seals (combated with Viton types on replacement). Emissions are incredibly good at MoT running SVO & the whole fuel system in general appeared cleaner after running Sunflower for a couple of years. The exhaust fumes smell nice too, but get too close and it's like you've been teargassed!

The one caveat I've always felt has been if a car sits long-term with veg oil in the pump, especially if it's lost prime and got air in the system. The stuff then turns to sticky goop much like it does in funnels and bottles if left in contact. Had a couple of pumps for 1.9TD engines I've had to go through due to gummed up internals.

However, having recently purchased our Disco 200TDi which has sat for over 16 years with straight sunflower in the system (from how dark it was, it might even be WVO also had a filter full of air and near empty tank to boot) this doesn't appear to have been the case in this one, once it was primed up again the pump appears to function OK although I'm still not 100% as not had a chance to get some fresh fuel and a new filter in. Time will tell as I know these pumps can trick you by partly functioning but if the vanes get gummed up you can get some strange symptoms from low transfer pressure.

Anyway that's just my take, thought I'd add it onto this thread just for the sake of it.
 
I did over 100000 miles on SVO in a 3ltr Merc with a DIY conversion, twin tanks, heaters Pollack valve etc. At the start the savings were good but I went back to dino 2 years ago after 6 years on SVO. My mileage had dropped and I found SVO made sense when you were driving a lot, buying in bulk, keeping the fuel moving and getting the engine hot. SVO did not work on short trips and days not using the car. I was surprised how reactive SVO is, it really dissolves a lot of things. I ran the Bosch in-line pump, they are bullet proof. I had a quite a few problems with gelling, one time the whole system set, it was as though certain things could set it off. Anything below 3C and it was goop. Learned the hard way to watch the weather forecast closely as an unexpected overnight drop could make may car un-startable unless I bleed it through the night before. Always cut it with 5% unleaded in winter.
When I sold the car with the full SVO conversion I got no extra on the price for it and I just chucked 80L SVO in to get shot of it. What did it for me other than the hassle was that I had gone into it for environmental reasons too but it had become clear to me that I was burning GM soya from felled rain forest in Brazil and that killed it for me. Its not easy to find where SVO is coming from but a lot is coming from recently felled virgin land as its a big cash crop and the more that is grown for fuel the more it displaces food.
 
I dont burn GM for those reasons Rob. Rape or Sunflower oil can be had for 70ppl when tesco have a deal on. I just buy all I can then and wait for the next deal.
 
Jonnymac2001 said:
Has anyone any experience with Kerosene.
Click to expand...

Yeah, I run my Isuzu 2.8T on Heating oil (Kerosene), mixed with a half litre of engine oil or 2 stroke for a bit of lubrication. No problems. It smokes a little on start, but clears up after 50yrds or so. Performance wise I notice no difference from diesel.
 
Barlow said:
Yeah, I run my Isuzu 2.8T on Heating oil (Kerosene), mixed with a half litre of engine oil or 2 stroke for a bit of lubrication. No problems. It smokes a little on start, but clears up after 50yrds or so. Performance wise I notice no difference from diesel.
Click to expand...
Why not just use red diesel, IIRC, the consequences are the same if you get caught?
 
The Kerosene in my bowser cost me ~55p a litre at the time. Diesel is more than 3x as much.
Why on earth would I use diesel.
 
Barlow said:
The Kerosene in my bowser cost me ~55p a litre at the time. Diesel is more than 3x as much.
Why on earth would I use diesel.
Click to expand...

67C0DE9F-9CC0-42D8-BDA3-E8F58F7330A7.jpeg


Using rebated fuels in vehicles and machines (Excise Notice 75) from 1 April 2022

Find out when you can use rebated diesel or biodiesel in vehicles and other machinery from 1 April 2022.
www.gov.uk www.gov.uk
 
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