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jojo Mud Obsessed
Joined: 11 Aug 2007 Odometer: 5422
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Posted: Mon Aug 13, 2007 8:18 pm Post subject: BP Ultimate
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Not sure if this is the right forum but . . .
Has anyone tried using BP Ultimate diesel? BP claim that it gives more MPG and less emissions. I tried it over 5 tankfulls and I got LESS MPG in my Disco 300 dti. I also have a Citroen Xantia and there was no difference.
Looking at the BP data it seems that they have "bench tested" it using modern high revving diesels running between 3,000 and 5,000 rpm. However, the 300 dti is an elderly low revving slogger and in my case usually runs between 1,200 and 2,500 rpm. My Citroen has a "middle aged" engine capable of running faster than the 300 dti, and usually running between 1,200 and 3,000 rpm, but slower than the latest generation of diesels.
I don't know about BP Ultimate petrol but unless you have the very latest diesel engine give BP Ultimate diesel a miss as it is just an expensive con designed to screw more money out of you.
Best wishes,
Jojo
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pdw666 Mud Obsessed
Joined: 10 Apr 2005 Odometer: 2043 Location: West Yorkshire
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Posted: Mon Aug 13, 2007 10:43 pm Post subject:
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I run on ultimate all the time, have done for quite a while now.
MPG is certainly better than on any of the supermarket fuels, and it's cleaner burning than BPs normal diesel, in the same conditions.
One thing that I have heard, 300 with the ECU fitted won't show as good a result as either a 200, or a 300 with the ECU blanked off.
Generally speaking, I think it's a good fuel, it certainly works fine for me.
Pete.
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Terranosaurus Articulating
Joined: 26 Apr 2007 Odometer: 949 Location: Bishop Auckland County Durham
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Posted: Mon Aug 13, 2007 11:01 pm Post subject:
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Engines have to be optimised to the fiel to get the best from it. If you're engine is neared to optimised for std fuel than it is BP ultimate it will run better on std fuel. The first of these new generation fuels was Shell Optimax - when it first hit the market a number of competition cars were remapped (ECU reprogrammed) to take advantage of it, some even stepping down from proper racing fuels as incomparision Optimax was cheap. Its all a matter of optimisation as is any engine tuning. If you read BPs blurb it won't say that but I bet thats hgow their tests were conducted. Engine optimsed to std fuel and then same engine optimised to BP Ultimate). With petrols theres more to play (because of the ignition) with but with diesels they can still mess around with the fuel pressure and timing to give best economy and power.
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jojo Mud Obsessed
Joined: 11 Aug 2007 Odometer: 5422
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Posted: Tue Aug 14, 2007 8:08 am Post subject:
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That's interesting. My 300tdi is bulk standard with an ECU and a cat. exhaust which seems to be designed to stifle performance and economy. If the exhaust packs up I will replace it with something different and try BPU again.
Best wishes,
Jojo
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Wabbit Gate Opener
Joined: 20 Jul 2007 Odometer: 7
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Posted: Thu Aug 16, 2007 9:31 am Post subject:
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@pdw666 - excuse my relative newbieness, but did you mean ECU, or EGR?
Unless I've been told wrongly, I thought it was the EGR (exhaust gas recirculation) that's best to blank off.
I tried a tank of ultimate diesel, I'm not sure it made any difference to my car, it seemed to make a difference to my wallet though.
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pdw666 Mud Obsessed
Joined: 10 Apr 2005 Odometer: 2043 Location: West Yorkshire
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Posted: Thu Aug 16, 2007 12:54 pm Post subject:
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Mea culpa.
Should have read EGR.
Pete.
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Andy Hamilton Mud Obsessed
Joined: 11 Apr 2005 Odometer: 2772 Location: Deep in Northumberland mud
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Posted: Sun Aug 19, 2007 9:46 pm Post subject:
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I have used BP ultimate in a VW tdi and I really never noticed the difference. I tried 4 tank fulls then gave up on the stuff. Went to local supermarket to fill up. The engine then sounded like a bag of hammers (like any diesel car) so I chopped and changed for a few tanks. The stuff does quieten down the engine and get a couple more horses but for 5ppl extra I stay clear.
Shell normal diesel gives me 5mpg extra for some reason and millers diesel plus gives me a bit extra poke if I'm using supermarket fuel.
__________________________________ I sell Bosch plug leads for suzuki's on ebay. I also give discount to difflockers! |
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:) Mud Obsessed
Joined: 06 Feb 2006 Odometer: 4337 Location: Norfolk
1995 Land Rover Defender
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Posted: Mon Aug 20, 2007 7:04 am Post subject: Re: BP Ultimate
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jojo wrote: | Has anyone tried using BP Ultimate diesel? BP claim that it gives more MPG and less emissions. I tried it over 5 tankfulls and I got LESS MPG in my Disco 300 dti... |
An increase in fuel consumption is possible at light throttle settings.
I guess that this so called "ultimate" fuel has in increased cetane rating. This is a measure of the delay between injection and ignition and can very loosely be thought of as the diesel version of 'octane rating'.
Diesel fuel injection starts before TDC in order to allow for the combustion delay, but if yours burns too quickly (higher cetane number) then you will get an excess pressure increase before TDC causing the engine to loose efficiency and therefore increase mpg. The way to cure this is to adjust the IP timing to retard it by a couple of degrees.
I saw this problem when I was using 100% bio-diesel which has a higher cetane number to fossil diesel. Vegetable oil tend to have a lower cetane number to fossil diesel, but is complicated by other factors which seem to make it hard to measure.
--
Tim.
__________________________________ -- Timothy Birt -- |
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