Motors Premium fuel

Good post.

How would YOU define this in terms of PSI?

 

A diesel doesn't care. As long as it's oily and it can burn there's nothing it won't eat.

 

If you can find somewhere that premium is the same as standard I'll eat my hat!

 

Always used to put premium in my bora, but it hasnt moved for 2 months since getting a work van, The difference was obvious to me.

The only thing that goes in any of our cars now is diesel.

 

I think it would be more efficient to say what I wouldn't bother with using premium on. If you are using anything called and "electric turbo" Don't bother as you are probably getting negative boost with it. Anything with up to around 8-9 peak psi of boost, most likely doesn't require premium fuel (unless your using a high compression ratio in conjunction with this, but if you are, please step away from your car and re-evaluate what you are doing. Since you will definitely see a larger benefit from using more boost rather than a higher compression ratio.)

Basically if you have any decent turbo (10 psi+) on your car you might want to consider using premium, since it would give you a little bit of a buffer against engine knock, since say if all the stars align against you, and you have a slightly sticky blow-off valve, it might save your engine.

 

That's me then. And anyone else with a VAG 1.8T with 180ps or more, or the newer 2.0TFSI. Which I would imagine, is quite a few people with what you might consider "mainstream" cars.

Interestingly, my old derv used to peak at over 1 bar!! I didn't use V-Power derv juice though.

 

Had a friend who was also convinced his little 206 was super zippy after putting in Shell high octane over standard Tesco stuff. I mean, STRAIGHT after he started it up at the fuel station.

MMm, what about the juice still in the fuel filter and the hosing? Retard

 

I can. I always use premium.

 

If I had a car with requires higher octance fuel, or has a knocking sensor then I would use it. Before the recent price hikes there was a Shell station that sold V-Power for the same price as another station sold 95 at! IIRC using higher octance fuel in a standard car wont increase performance, but it would probably benefit from the extra additives. I think tesco's premium fuel is actually a higher octane rating than BP's - 99 to 97.

 

Right folks, do not buy supermarket fuels. Although in theory the fuels from the pumps should be similar except for the additives, it isn't true.

The oil companies own various refineries throughout the UK and produce the fuels. Depending on who owns the local refinery will determine which petrol station gets the best fuels. For example BP used to own Grangemouth refinery and gave their petrol stations in that area the best cut, Southampton Refinery is owned by Exxon Mobil so give Esso the best fuel.

However, there isn't that much of a difference between the oil companies fuels as if say Total bugger up some Esso fuel from the Lyndsey refinery on purpose then Exxon Mobil will then bugger up some Total fuel in another part of the country such as at Southampton. So generally they play nice to one another.

The supermarkets do not have this capability as they don't own any refineries so can't exert quality control over the oil companies so basically they get the worst cut throughout the country.

 

Well, what does VW say to this?
You think they give you a car that NEEDS 99 RON, but put a 95 RON sticker on it just for the heck of it?
If they designed this car to use 95 RON, that's it, no matter how much boost or overboost you measure.

Of course if you start tweaking...that's another story. If you up the boost yourself, yeah, then it makes sense.

My Coupe run's a factory oberboost of 1,2 Bar and only uses 95 RON
When the boost-control-valve broke, the needle jumped of the meter at somewhere over 1,5 bar though I had serious doubts there. Fixed it now.

 

Depends on the car's map. Quite a few cars have knock sensors, so they can retard ignition if you put say 92 RON in. They don't have a map for 98/99 RON, so despite the knock sensor picking up higher octane fuel, it can't use it.

Still there's no need to test or wonder. The car manual has it in. Most manuals will say 'use 95 RON'. Some manuals (higher perf cars) will say something along the lines of '95RON minimum, 98RON for best results'. Finally if you have a crazy powerful car (looking at TVR), it'll say '98RON minimum'.

The manual helpfully spells it out so you don't need to worry about the placebo effect.

 

I'm not so sure about this, I thought the point of a knock sensor is that the engine is able to advance the ignition as far as it can without knocking - which would take care of the "low quality" fuel while also increasing performance and economy with the higher octane stuff.

I think the point is that you can't just give a blanket answer as to whether it's better or not for all cars and all driving styles. I know my old Golf used to pink like crazy on standard fuel, especially at WOT and high revs as those engines run very lean in this range anyway!

 

Ah a man with taste! A very tunable engine, just up the boost and pray the fuel prices don't keep going up and up.

Avoid the 740, and get a 940 to drop a b230ft in, they came with more kit and the gearbox plus the rear diff seem to last longer with these power levels.

I use supermarket fuel due to cost, 80 mile round trip a day in a petrol soon shows the difference in price. Oddly Sainsburys fuel seems smoother and refined where tesco's makes it run like i poured a bag of nails in, idle is all over the place it picks up strange, smooth progressive pull, then farts some power and back on again. very odd experience!

My car is 16 years moving on 17 years old, engine management is basic, very basic!