Is it worth using 98/99 RON petrol?

**Doug-SRidirect** · 5th October 2005, 19:12

I read in my handbook that the engine adjusts itself (presumably the timing) to suit the octane rating of the petrol used.
This would suggest that there may well be benefits in terms of fuel economy (and maybe even performance) from using super unleaded.
I filled up tonight at Tesco and treated my 2.2 Direct to SUP (99 RON) as it was only 4p a litre more than standard 95 RON unleaded.
That's only 4% more. If I get similar increase in MPG (from say 35 to 36.5) I'll be in pocket.
Driving back tonight it's was obviously too soon to tell if it is running any better but I'll monitor my consumption (and feel of the car) and see how it goes.
Obviously, some of you will have tried this already. Any comments anybody?

Doug

**Scooby** · 5th October 2005, 19:20

Me and Big Phil did a cheap little test on the run up to Tunit last Saturday...he filled up with high octane Total and i filled up with normal ( im a cheapskate! )..both of us have Gsi 3.2 V6s and on the way back home after both of our cars had been rolling roaded at max revs it was me who had the best mpg ( approx 3-4mpg more ) and 9bhp more on the r/r....for me ive sacked the idea of using high octane and im gonna stick with 95r.

Edit** Doh...cheers Phil..i meant 95 m8...have changed it.

**big phil** · 5th October 2005, 19:29

95 ron scoob' 97 is su not seen 99 ron b4 doug ??not at the pumps any how ??

**Doug-SRidirect** · 5th October 2005, 19:39

'must have been mistaken. I though I saw "99 RON", but I too think that can't be right. Anyway Tesco Hemel Hempstead: UL @ 93.9p / litre, SUL @ 97.9 / litre.
Probably it was 97..........new glasses required!!!

Doug

**Lloydy** · 5th October 2005, 20:16

Originally Posted by Scooby

for me ive sacked the idea of using high octane and im gonna stick with 95r.

There must be some gain though. What motivation do the fuel companies give for getting us to use it?

1) Better fuel consumption? Apparently not!
2) Better performance? Also apparently not!
3) Better engine wear? Who knows?

Of course, to be more meaningful you need to repeat the exercise when both using the same fuel, or maybe swapping over, since there may be some difference between the engines or driving styles.

**Andy M** · 6th October 2005, 21:34

Originally Posted by Lloydy

There must be some gain though. What motivation do the fuel companies give for getting us to use it?

1) Better fuel consumption? Apparently not!
2) Better performance? Also apparently not!
3) Better engine wear? Who knows?

I think the answer is better profit. Last March I had to drive 4 times to just south of Paris. I tried using SUL vs. normal as it was a consistent long run. For my car there was no benefit whatsoever - I simply couldn't see any difference. Top speed was the same. Other performance was no difference that I could tell and economy was near enough identical. If the wholesale cost of unleaded is 25p / litre excluding tax then an extra 4p is more than 10% extra profit for the petrol company.

Maybe it makes a difference to a Ferrari but not to normal cars which are tuned for normal petrol.

**POAH** · 6th October 2005, 22:42

Originally Posted by Doug-SRidirect

'must have been mistaken. I though I saw "99 RON", but I too think that can't be right. Anyway Tesco Hemel Hempstead: UL @ 93.9p / litre, SUL @ 97.9 / litre.
Probably it was 97..........new glasses required!!!

Doug

Tesco are selling 99 RON petrol in some stations

**Jamie** · 7th October 2005, 00:07

99 RON is here.... they made a big thing of it at Rally GB..... they sponsored a Scoob team for the event.

Anyway, must be good stuff cos the Scoob ended up launching itself into the scenery on Rheola Special stage and look more like a Justy than an Impreza when they dragged it out!!!! (Driver and Nav walked away unhurt)

I use Tesco 97 RON and I get about 8% better range out of it by my limited maths!!!!

**VectraV6CDTi** · 7th October 2005, 12:57

I use Shell Optimax all the time. Definatly better performance with it in and the other day I let the fuel gauge get lower than normal and I got 407 miles just as the fuel low warning light came on - so still probably another 30 miles left in it.

**big phil** · 7th October 2005, 20:57

Originally Posted by VectraSXi

I use Shell Optimax all the time. Definatly better performance with it in and the other day I let the fuel gauge get lower than normal and I got 407 miles just as the fuel low warning light came on - so still probably another 30 miles left in it.

might be for a smaller engine , but optimax doesn't suit the gsi at all , ''lumpy bumpy and grumpy''