I want to conduct an experiment with my Fabia vRS (3500 miles, std tune).

I wish to establish what effects, if any, running various blends of biodiesel and mineral diesel have on the car. Having tracked down a local source of a 5% blend (i.e. 5% bio 95% mineral) I need to know what measurements it would be sensible to take while generating a log using my Vag-Com.

I am thinking initially that MAF, quantity injected and RPM would be a good starting point. Can anybody think of any others?

I can also measure mpg and make subjective judgements on noise, accelleration, particulates etc.

I don't have access to a dyno, but it might be interesting to take standard measurements (bhp, torque etc under standardised conditions)with different fuels but this would be expensive and time-consuming.

The measurements would be repeated with different %age blends, including blends with different mineral diesels.

Any thoughts/opinions/offers of collaboration welcome. I'll let folks know what the results are.

TIA

bryand

Can't help on the technical side, but I've been running 5% biodiesel in my PD100 for a couple of thousand miles now and am very happy with the results so I'd be interested to see your results. Maybe I should switch back to normal mineral diesel for a couple of tanks and see if I notice a difference

If you want any help, give me a shout as I have a VAG-COM

Chris

Im not sure the performance benifits / problems could be measured with VAGcom... apart from maybe the flywheel torque which isnt really accurate anyway.

The problem lies is that unlike petrol motors, which have knock sensors to compensate for lower quality fuel... there are no "adaption" functions on a tdi engine.. the only way to tell would be gain/loss of power or more/less soot.

I can tell you in my 1 tank of tesco 5% bio experieince, it is expensive and reduces mpg and power. Both are noticable to the point that I will not use bio-diesel :( real shame as I like th idea, it is just not viable for me. If I had to put numbers on it I would say over the course of a tank the normal distance I will cover is 480 miles (varied driving, 60miles a day motorway, lots of fun on twisty roads at weekends!) and with bio that dropped to about 440. I think some of the problem was me burying my foot more to compensate for the power loss.

Mind you, that is still better then my old 1.6 petrol focus!

As a rule i *never* use supermarket fuel... as compromises have been made- especially with petrol. and these days, big name forcourts price match anyway... tiz always Shell, BP, Esso for me in that order.

As a rule i *never* use supermarket fuel... as compromises have been made- especially with petrol.

Any more info on these compromises?

All comes from the same gantries AFAIK!

Rob.

ditto! Please tell me!

Also, what is "city diesel" and should it be used ????

is their a diesel faq? If not anyone who knows about it want to write one?

Also, what is "city diesel" and should it be used ????

AFAIK, city diesel is just low sulphur diesel so less "polluting".

Chris

The base is very similar depending which refinery it comes from but a whole bunch of additives are added by the vendor in this case shell/bp but AFAIK the supermarkets dont have a crack team of petrochemists stacking their shelves....

The problem lies is that unlike petrol motors' date=' which have knock sensors to compensate for lower quality fuel... [/quote']

Neo not all petrol motors have knock sensors.

As a rule i *never* use supermarket fuel... as compromises have been made- especially with petrol. and these days, big name forcourts price match anyway... tiz always Shell, BP, Esso for me in that order.

Im with you on this one, I have noticed a substantial difference both in performace and economy using Shell, BP and Esso fuels, especially towing