Tesco 99 Ron - Locations and avaliability

[bulk66]

I'm sure i heard that 99 will soon be available @ all Tesco stores in the next few months. 

[silkyballs]

check out northants area and bedforshire!im spoilt for choice all with in15 miles!lol

[jezza16v]

Why all the fuss about 99 RON, its of no benefit at all in any Mk2 unless the engine is modified such that it needs it. It can only be of benefit in modern hi tech engines with very sophisticated engine management which can adjust the mixture and ignition timing to suit. Mk2's just don't have it. There is no more 'energy' available in 99 RON over 95 RON, the higher RON's just have additives to control the 'burn' rate (which is what lead used to do) which allows for a higher state of tune.  Feel free to waste your money if you like!

[bulk66]

My 8v should run on 98 it has a 98ron sticker on the inside of the filler flap its origanal i think. So mine could of had the timing messed around with to run normal ron. Ive never had any problems with normal fuel, ticks over fine and gose well.  

[jezza16v]

Thats fine if it doesn't pink.  What I was trying to say is that you will not gain any performance if you use a RON rating which is higher than is stated as necessary for the vehicle. My 16v says 98, I use Tesco Super which I think is 97 and that's near enough for me. I think Optimax is 98, but I'm not paying the extra. If you run a lower than stated RON then you run some risk of burning the valves if 'pinking' occurs. If you're confident that the engine is not 'pinking' with 95 RON then go for the cheaper stuff. There's a good chance, in higher mileage cars, where the compression is likely to be down a bit, that 95 will be OK, but I would advise you stick to the stated RON unless you know exactly what 'pinking' sounds like. 

[silkyballs]

i maybe spoilt for choice but i just pull up at the pump and fill up! if i put optimax in her she defo runs better but its not worth the extra!

[Agreeable Slick]

The main reason is that earlier cars did not have hardened valve seats which meant that they needed to run aon a lrp subsititure to keep running as they should. The reason 16v are designed for higher octane is that there were engineered with hardened competition valve seats, which meant they could run on the 98 RON stuff, it also allowed them to be run harder and with more revs, whereas the earlier models of car would have begun to get tappety a lot earlier.

The higher octane a petrol is, the lower the chance of pre-ignition, leading to a f**ked head if not careful. My valver definately feels more pokey because of it.

[jezza16v]

Please look here, don't waste your money      http://www.carbibles.com/fuel_engine_bible.html

[Agreeable Slick]

so basically what i and everyone else has already said then. Use the higher octane stuff as it is better for the engine.  it mentions all the stuff about LRP being needed for lubricating the valve seats, explains that you cannot achieve the same MPG on a lower octane fuel, and also that in the long run not only is a lower octane going to knack your engine, but will end up costing you more on everyday re-fueling and running costs. 

Conclusion = run higher RON petrol. I.E> 97+

[jezza16v]

Absolutely, if the book says 98 RON then use it or as close as you can get, if it says 95 RON is OK then use that, ...however using 99 RON in an engine designed for 98 or 95 gives no performance or MPG advantage over what the engine is designed for. Using 95 in a 98 engine will reduce mpg and risks pre-ignition and hence valve damage, but its certainly not worth driving an extra five miles to fill up your Mk2 GTI with 99 if you can get 97 or 98 locally so the availability (or not) of 99 RON at your local Tesco is no big deal.