Diesel 50ppm vs 500ppm

[Slade2000]

Hi

I drive a 1.5 Turbo Diesel Hyundai Getz

I have a question. I know why you should use 50ppm rather than 500ppm diesel but my question is why does it make such a big difference in fuel economy and in my sense the wrong way. On 500ppm i get average of 740 km per tank of diesel but with the 50ppm i get only average 640 km on a tank. i have done this with a few tanks to make double sure i take in consideration drive style and every thing and every time it comes to the same.

Can any one explain this maybe?

[Naks]

I know why you should use 50ppm rather than 500ppm diesel but my question is why does it make such a big difference in fuel economy and in my sense the wrong way. On 500ppm i get average of 740 km per tank of diesel but with the 50ppm i get only average 640 km on a tank. i have done this with a few tanks to make double sure i take in consideration drive style and every thing and every time it comes to the same. Can any one explain this maybe?

You should use 50ppm because it has less sulphur. Sulphur is bad because it reacts with moisture to create sulphuric acid, which corrodes the internals of the engine. By using 50ppm your engine will last longer.

You are also not the first diesel owner to report less mileage on 50ppm than on 500ppm. I guess the downside of 50ppm is that the process of removing the sulphur also lowers its cetane index - can anyone confirm?

But by far the biggest problem with 50ppm is the reduced lubricity of the diesel, leading to premature (and expensive) failure of CRD components like the diesel pump, etc. Fortunately this is easily remedied by adding some 2-stroke oil with every tank.

[Slade2000]

Yes all the pros and cons i read was all the same like you mentioned but with the fuel price now 100km a tank is allot and will not drive the car so long that if i keep on using 500ppm that i will experience the corroding problems.

[Jola]

I have had problems lately in finding the 50ppm diesel, some suppliers like Engen don't stock it any more.

So I tend to fill up at Caltex garages.

I haven't noticed an increased fuel consumption with 50ppm.

I do add 250ml high quality two-stroke oil to each tank of fuel.

BTW, I was in California recently, and the only diesel available for passenger vehicles is 15ppm.

[herit]

Yes all the pros and cons i read was all the same like you mentioned but with the fuel price now 100km a tank is allot and will not drive the car so long that if i keep on using 500ppm that i will experience the corroding problems.

One other thing to take into account is that with using 500ppm, the service intervals are/should be a more frequent. The extra sulphur makes the oil sluggish.

[Sinbad]

Slade2000 which brand of 50ppm did you use?
I found that my consumption on sasol 50ppm was a LOT worse than shell vpower 50ppm.
Idle consumption with aircon off on Sasol was 1.1l/h and on Shell 0.7... Never got to the bottom of why...

[Slade2000]

yes shell gave me the best as well. im only on 500 now. my best i got with 500ppm was 4.9/100km i can only dream to get that on 50ppm

[danlr]

I used to drive with 5ppm in the UK and now only use 50ppm as 5ppm isnt available...

Performance on the car is definitely a bit sluggish but there is probably a lot of variables such as air pressure etc.

I know some car manufactures will void warranty if you use anything else but 50ppm in SA.

I use BP ultimate and usually get around 6.5/100km in town and it drops to about 5.7/100km on the highway

[Fazda]

I don't know about your car, but all the Euro 4 spec diesels run closed particulate filters, and they have to run on 50ppm as the worst, otherwise the DPF collapses and it will cost you between 30 and 40k to replace the thing.

Double check with your dealer as whether you can actually use 500 ppm, even if you get better consumption. If not you will definitely be in for shorter service intervals at best and a bloody expensive repair bill at worst.

[HammerDown]

Yeap...soot and new gen car diesel engines do not go together very well. Added to what Fazda said soot also builds up in your EGR which, when stuck through excessive soot buildup, makes your car sluggish, rough idling and adversely affects performance. It gets worse as the soot gets sent back in your inlet manifold it mixes with oil mist from your crankcase breather/turbo seal seepage and forms a tar like mess that coats your inlet manifold over time...

These guys were not designed to run on truck diesel.

FWIW: The lower the PPM the less soot is produced (the sulpher produces the particulates or soot) and the happier your engine will be/stay in the long run.

[Colin62]

I've also found that I get better mileage on 500ppm, but it's not a huge difference. I usually use 50ppm, but out in the sticks you often don't have much choice, and as the car was happily driving around before 50ppm was available, I reckon the engine can easily cope with 500ppm, so if that what's available, that's what I'll use.

The soot build-up in the EGR and the resultant billowing clouds of smoke make the while point of EGR a little hard to fathom. Everyone I have heard of who has disabled their EGR reports lower fuel consumption and less smoke, so why the EU insist on EGR to decrease pollution is a little difficult to understand.

[Fazda]

Colin, you obviously have a car with an "open" particulate filter, or you wouldn't be using 500 ppm so happily. The new "closed" filters on the Euro4 spec diesels, simply cannot handle the 500ppm without blocking up completely.

The 500ppm also messes up the oil in the car, and services will be more frequent if you want to keep the car running properly.

The exhaust in my current diesel is absolutely clean, you can wipe a white cloth in it and it remains clean - zero soot.There's also no diesel smell when it idles, so that DPF is obviously doing something good!

[Colin62]

Yes, it's a 2005 model, and doesn't have a DPF fitted. It's also got 375 000km on the clock, which means I've pretty much got my money's worth out of it already, and any more I get is bonus. :-)