Only ever use Shell or BP fuel anyway but is there any draw back with useing standard 95 ron fuel will it damage the car?

Or is it just a decrease in performance, day to day i dont really blast the car anyway

Not only a decrease in performance, but economy too... I used to run mine on 95, then made the switch to VPower exclusively about 10 months back. When I couldn't get any recently I had to put in a nominal amount of BP 95 to get me to the next Shell garage (gig in the *rse end of nowhere late at night!) and the car felt like an absolute dog! Though this may be down to the adaptive ECU, it still felt far rougher than normal. I get about 20-30 miles more to a tank on 99 (even more when 'touring' at NSL) than 95, also as I understand it the higher octane results in a hotter, cleaner burn, thus keeping everything cleaner than when using 95. I may be wrong on this, in which case I look forward to the far more knowledgeable members around here pointing me in the right direction

I see it as a few more quid every tankful that keeps the car quicker, smoother and burning fuel more efficiently.

I, and im sure many others will tell you, that you must use 98ron (i believe it even says it in the filler cap on some models).

I have a heavily mapped car running up to 25PSI of boost and have been known to run on stock 95 for periods (when i cant get 98 to hand) and the car does perform worse and with lower fuel economy. It still runs smooth but a definate lack of power.

As you car is not mapped (yet ) then i am sure sticking the odd tank of 95 in will be fine from time to time but i would advise 98 or above when ever you can.

I hope this helps.

Garry

many thanks for the advice it does say to use 98 ron on the filler cap and ive only had it a week. Got 230 miles out 30 quid s worth of optimax so i cant grumble really.

Was just checking.

Many thanks for the advice.

P.S What a sweet car!!!!

Happy Motoring

Garry

Same here, I find 98 or 99 RON gets me more miles than 95 RON (if driving sensibly) and this just about makes up for the difference in price.

I get 370 miles from a £52 tank of Optimax, not bad for a 180bhp car

this has been covered lots and lots mate.

but,

I have had my car from new in 05 and have used:

shell optimax/Vpower

shell unleaded

BP unleaded

BP ultimate

Tesco 95

Tesco 97

Tesco 99

Sainsburys 97

all on the std car and remapped on generic maps and the custom one I have now.

std car:

ran pritty much the same on all, nice and smooth and reasonable economy. the best was tesco 97 for economy and 99 for performance. I ran mine mostly on 95 as it wasnt worth the extra ££ as I couldnt get the extra out the tank.

generic map(both were ****e ones thou)

again didnt really seem too different. all were ok but the BP ultimate was no good at all, felt worse than 95. there did seem bit less go in her on the 95 rons than the Vpower and 99. again 99 was the nicest. but still not cost effective and drivability was very similar.

Custom job(couldnt get 99 so had to use vpower)

coz the car was mapped on vpower she runs best on it. only used 95 once as there was no other a few week ago and NEVER AGAIN! it is so bad you wouldnt beleive. tesco 97 is good for economy and doesnt loose too much power, 99 is good power but doesnt run as smooth, the sainsburys 97 is the best all rounder as its cheapest and good power and economy.

adn out in front is the Vpower, very good fuel eco(200 mile trip from huddersfield to bristol 65-70mph average= 43mpl on trip with 2 ppl in car and a full boot) and she goes like stink.

my mods ar in the sig mate. work out what it costs to fill up on Vpower and 99 then the price of 95 and see what milage you get on the 95 and price it per mile then see what milage ull need to get from the tanke of Vpower and 99 lol

i did, and iirc 7.4mpl on 95 is what i got on std car and id need something like 8.2 on V POWER for it to be cost efective and on the normal drive it is nion impos.

billy

i find mine both run a lot better on 99 ron but out of them all i find that they perform the best on tesco s brand

I am very confused by all the discussions I see regarding which RON to use. My petrol cap (below) clearly says 95 RON - but it also says Super Unleaded. My engine is 2 litre on a pre-reg that dates back to last summer.

I have had it for a few weeks now and have only used ordinary 95 RON. What I would like to know is:

will I get better MPG with a higher RON?

will I get better acceleration with a higher RON?

will the engine run smoother with a higher RON?

how long will it take for the engine to recognise the higher RON and deliver the benefits?

The 1.8t should be run on 98RON

Standard fuel here in NZ is 91 with 95/96 sold as premium. It's harder to find 98!

I get about 50km per tank more on 98 than 95

I ran my mk1 1.8T elegance only on 95ron, and never had any issues. Always got 38+MPG and no performance issues.

Many other members here run theirs on 95ron.

It runs fine on 95 - but better on 98

IMHO of course

on the std car its fine on 95 and the diff is not really worth the extra money. once you get remapped tho it makes more diff, deppendin on the map of course.

end of the day its up to you what you want to use mate, petrol is petrol and will still get you to were you want to go. I recon a lambo or an aston will run on 95???? just with reduced power.

might be wrong but isnt petrol all the same? I seem to remember that its only aditives that bring it up to the ron levels?

eg:

V Power is 99ron

Tesco 99 is 99ron

so in theory it should be the same but my car is smoother on V Power than Tesco 99..... wierd lol

billy

Yup each fuel retailer has their own blend that makes up their fuel. Additives such as acetone etc etc as well as the cleaners.

It's the additives some cars like and others dont. Hence my advice always being find the fuel your cars likes, than than going for it by brand or because you get points there.

As far as derv goes, City is usually regarded as good stuff, and only available outside london through sainsburys AFAIA. Petrol is petrol is petrol.

. I recon a lambo or an aston will run on 95???? just with reduced power.

might be wrong but isnt petrol all the same? I seem to remember that its only aditives that bring it up to the ron levels?

I reckon an Aston or a lambo might be a bit poorly if it ran on RON95 fuel. The whole need to have the different types of fuel available is ONLY due to certain cars needing higher octane rating fuel compared to others.

Basically, your top end sportier cars, by virtue of design, have a higher compression ratio. (to get more power) but in doing so the chances of the fuel detonating increases due to the higher pressure. A higher octane fuel has added chemicals that actually slow down the burning of the fuel which in turn reduces the chances of pre dotonation.

So, in a nut shell. High compression engines need high octane rating to stop the engine killing itself. Not to produce more power. All the octane rating means is a measure of the maximum compression ratio at which a partiqular fuel can be burnt without detonation. So, if your car says use it, then you really should. If it doesn't say use it, well, no harm done if you do. And as for using it after mods and remaps, thats another point of debate.

cheers for clearin that up mate

surely when you get bigger turbo youd need to go to better fuel? doesnt doing the BT thing up the compr ratio?

if not how do you up it?

billy

I wouldn't have thought getting a bigger turbo would affect the compresion ratio as its just the ratio between the combined volume of a cylinder and a combustion chamber when the piston is at the bottom of its stroke, and the same volume when the it's at the top of its stroke.

The cars ECU would compensate (obviously you'd need the car re-mapping) for the increased flow of air into the engine that the bigger turbo is now allowing. And also, depending how big the turbo is, you'd need bigger injectors, fuel pump and a uprated fuel pressure regulator. Getting the head skimed would increase the compression ratio tho.

I can confirm that the dynamic compression ratio does indeed increase when the boost preasure increases

Garry

I can confirm that the dynamic compression ratio does indeed increase when the boost preasure increases

Garry

That is true, however in my post (and what most people think of as a compression ratio) I was talking about static compression ratio. where as the actual "pressure" in the cylinder is often called "dynamic"