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Re: Petrol quality

Posted: Thu Dec 20, 2018 12:51 pm
by om15
Many of the car articles in the press actually question the benefits of fuel additives, my local garage always puts in a measure of cleaner at each service, certainly cars/bikes go better on Shell and BP premium brands.
I will carry on adding redex as preventative maintenance as it doesn't really cost much to periodically put some in before a long run.

Re: Petrol quality

Posted: Thu Dec 20, 2018 1:53 pm
by izod tester
Some years ago I was driving down to the Alps in the 2.2 DCi Nissan X-Trail which I had then which severely lost power some 20km after filling with diesel at a supermarket near Dijon. Stopping and restarting and the motor would run properly for a few km if I avoided hard acceleration before losing power again. The Renault dealer at the village where we were skiing diagnosed a fault in the acceleration control system but could not obtain the correct spares during our stay there so made some adjustments which made the car much better, all for 20 euro. The motor went made it home ok where the Nissan dealer diagnosed a suction control valve problem which he said was caused by poor fuel with insufficient or no lubricity additive. He said the same problem occurred in UK with motors that habitually used supermarket fuel. He also said there could be problems if fuel was bought from a garage that had a very low turnover of fuel since the fuel deteriorates with long storage.

Re: Petrol quality

Posted: Fri Dec 21, 2018 6:52 pm
by Bob
Esso Super is the only unleaded I know in my area with no Ethanol in it so I buy that as I will not allow ethanol anywhere near my aeroplane's fuel system
I test it regularly, but I have no idea what they use as instead of Ethanol

Re: Petrol quality

Posted: Fri Dec 21, 2018 7:23 pm
by k3k3
When I owned a 2013 Diesel Jaguar with a Ford derived V6 engine, a petro-chemical engineer of my acquaintance said although it wasn't necessary, if it was his car he would add 0.5% low ash mineral based (not synthetic) 2-stroke oil every time I filled up due to lubricity problems with modern fuels.

Re: Petrol quality

Posted: Fri Dec 21, 2018 10:09 pm
by Pontius Navigator
K3k3, as many have done I put petrol into my diesel. It ran but a bit rough. Then I realised what I had done. Recovery was uncomplicated but my garage also recommended adding oil. OTOH other advice was that it made no difference.

Re: Petrol quality

Posted: Mon Mar 04, 2019 4:58 pm
by 1DC
A friend who was a chemical engineer in an oil refinery always advised putting higher grade fuels in our car because the higher the octane the more lubricant the fuel contained, and this would be better for the engine.

Re: Petrol quality

Posted: Mon Mar 04, 2019 5:11 pm
by Undried Plum
Burning irreplaceable petroleum fluids for propulsion in road and rail vehicles! :))

How very 19th century!! =))

Re: Petrol quality

Posted: Mon Mar 04, 2019 5:15 pm
by Pontius Navigator
Yeah, bring back charcoal burning steam cars.

Re: Petrol quality

Posted: Mon Mar 04, 2019 5:21 pm
by Capetonian
A friend who was a chemical engineer in an oil refinery always advised putting higher grade fuels in our car because the higher the octane the more lubricant the fuel contained, and this would be better for the engine.
Old myth, wrong.
You should run a (petrol) vehicle on the lowest octane rating on which it will run without pre-ignition (pinking) and the best oil you can afford.

Re: Petrol quality

Posted: Mon Mar 04, 2019 6:12 pm
by Fox3WheresMyBanana
Agreed, Cape.
I have been struggling, on and off for over a year, with rough running on one cylinder of my truck. The solution eventually turned out to be new sparkplugs, a new coil, and replacing the fuel injector electrical connector. During that time, the truck has been very sensitive to fuel quality. In my investigations I uncovered the following that may be of use. Winter fuel has a slightly lower calorific value, the negative effect of ethanol in fuel increases quite markedly as the fuel ages, especially for fuel tanks that aren't kept full, and the amount of detergents and other additives in fuel can vary quite a lot from one company to another. The ethanol in fuel is worse than Governments would have us believe, and some manufacturers are trying to get round the problem. I noted locally that Husqvarna sells premix fuel/oil for its chainsaws with the major selling point being that, because it's premix, the regular gas in it has no ethanol as this gets round the regulations.
In Canada, there is a group of companies that guarantees good levels of detergents and additives, but many of the cheaper fuels achieve this by putting in nominal amounts that just meet the regulations. In my experience, Shell has always been good, in the UK also, even for regular gas. I now find Esso to be good, and they have changed the formulation recently and are advertising that fact.

Re: Petrol quality

Posted: Thu Mar 07, 2019 5:23 pm
by Smeagol
1DC wrote:
Mon Mar 04, 2019 4:58 pm
A friend who was a chemical engineer in an oil refinery always advised putting higher grade fuels in our car because the higher the octane the more lubricant the fuel contained, and this would be better for the engine.
Ah! Chemical (or Process) engineers. Good at doing hard sums but often need a minder for everyday tasks like crossing the street.....

And maybe not best qualified to advise on fuel usage in road vehicles.

Re: Petrol quality

Posted: Thu Mar 07, 2019 10:02 pm
by 4mastacker
Fox3WheresMyBanana wrote:
Mon Mar 04, 2019 6:12 pm
................. the negative effect of ethanol in fuel increases quite markedly as the fuel ages, especially for fuel tanks that aren't kept full, and the amount of detergents and other additives in fuel can vary quite a lot from one company to another. The ethanol in fuel is worse than Governments would have us believe, and some manufacturers are trying to get round the problem. I noted locally that Husqvarna sells premix fuel/oil for its chainsaws with the major selling point being that, because it's premix, the regular gas in it has no ethanol as this gets round the regulations.
.........................................
My canal society bought a DR wheeled strimmer fitted with a Briggs & Stratton 4-stroke engine. The user manual said to use only a pre-mixed ethanol free fuel (ASPEN 4). At £19 for a 5 litre container that's bloody expensive when you've got over 4 miles of canal towpath to strim. We've got round that by using super-unleaded which doesn't affect the engine's performance and is a damn sight cheaper.

Re: Petrol quality

Posted: Thu Mar 07, 2019 10:10 pm
by Fox3WheresMyBanana
What engine is it? The Briggs & Stratton motors over here only recommend ethanol-free, not require it.
https://www.drpower.com/_drp/downloads/ ... 180815.pdf

Here is the 6.75 engine trimmer manual, see page 10. 10% ethanol OK

Re: Petrol quality

Posted: Fri Mar 08, 2019 2:50 am
by llondel
I know people who reckon that if you've got a marginal car when it comes to California smog testing, giving it a couple of tanks of the super expensive stuff before taking it in for the test maximises your chance of passing. No idea if that's true.

Re: Petrol quality

Posted: Thu Mar 14, 2019 4:10 pm
by 1DC
I have a Jaguar XF, it is 3 years old and i have only ever used Shell V Max diesel, yesterday i realised that Regular diesel at Sainsburys was 20p a litre cheaper so i filled up with the cheap stuff. I didn't notice any difference in performance but did an 80 mile round trip mainly on a motorway and the mpg dropped from a usual 53mpg to 49mpg. I will see if i notice anything else in the next month or so..
our other car is a Mercedes GLC, petrol. It costs £38 to do 200 miles in the Merc and £27 to do 200 miles in the XF..

Re: Petrol quality

Posted: Thu Mar 14, 2019 4:42 pm
by Fox3WheresMyBanana
I am fortunate in being able to buy a good fuel injector /top end engine additive by the gallon. The cost saving in getting the supermarket (equivalent) gas here is about 2c, but the additive works out to be about 3c when bought in bulk. So, on balance, I will stick with the better fuel (Esso is nearest me) and put in less additive. However, I have found the additive to be effective if used about once every 4 fill ups (my truck takes about 26 gallons), as I have 12 years of muck to continue clearing out from previous owners. The mpg is still within 2% of book value after 200,000 miles on a long run (i.e. 2,000+ miles ;))) ), but the additive keeps the injectors clean at least. I can tell as there is a short bit of rough running after a shot of cleaner as the bits/gunk gets cleared, then the acceleration is noticeably freer.

Re: Petrol quality

Posted: Fri Mar 15, 2019 8:27 pm
by 4mastacker
Fox3WheresMyBanana wrote:
Thu Mar 07, 2019 10:10 pm
What engine is it? The Briggs & Stratton motors over here only recommend ethanol-free, not require it.
https://www.drpower.com/_drp/downloads/ ... 180815.pdf

Here is the 6.75 engine trimmer manual, see page 10. 10% ethanol OK
Apols for the tardy reply. I had to check it at our depot. It's a 725 series engine. I think the firm may have been trying it on to make us buy the Aspen 4 fuel.

Re: Petrol quality

Posted: Mon Apr 15, 2019 7:06 pm
by OFSO
See my post elsewhere re the Magic Juice Ford put in petrol engines an hour or so before the annual pollution test. Always pass !