I have a 1.8 TSI with a 6-speed manual on my '09 FL

I had been putting normal unleaded fuel till now ...however after a suggestion from a friend I have decided to go for high octane fuel...

PROBLEMS-

1) Tank flap say 91/95 RON/ROZ...now here in India we don't get 95.... however 97 is easily available !

2) Is it safe to put 97 octane ?.. I know the purer the petrol better for the engine ...(but if thats the case then they would have mentioned 97 on the flap ).....I'm not really confident in doing this though .

Anyways can anyone help me clear this out please.

Thanks alot !

Edited 20 April, 201115 yr by pz1811

I have a 1.8 TSI with a 6-speed manual on my '09 FL

I had been putting normal unleaded fuel till now ...however after a suggestion from a friend I have decided to go for high octane fuel...

PROBLEMS-

1) Tank flap say 91/95 RON/ROZ...now here in India we don't get 95.... however 97 is easily available !

2) Is it safe to put 97 octane ?.. I know the purer the petrol better for the engine ...(but if thats the case then they would have mentioned 97 on the flap ).....I'm not really confident in doing this though .

Anyways can anyone help me clear this out please.

Thanks alot !

I put 98 in mine from new because the fuel filler door said use the supreme grade, but it turned out that meant the higher out of 91 and 95, because 95 is the higher grade on the continent. So I changed to 95 and it seems to run exactly the same.

I can't see why 97 should cause any harm.

If we assume that both fuel tests are to European Research Octane Number standards, 97 Octane should be ok, but may burn the valves if the car's not re-mapped.

If India tests to a different non-RON standard, I have no idea!

If we assume that both fuel tests are to European Research Octane Number standards, 97 Octane should be ok, but may burn the valves if the car's not re-mapped.

If India tests to a different non-RON standard, I have no idea!

Don't these cars have a flash ecu.....i.e. change the mapping according to the quality of fuel used ?

Correct me if I/m wrong !

Don't these cars have a flash ecu.....i.e. change the mapping according to the quality of fuel used ?

Correct me if I/m wrong !

I read somewhere on the forum that after a tankful or so of the "new" octane, the eletronics adjust to suit.

Anyone for more opinions !

Steer clear of 'Speed 97' as this often contains octane boosters such as MTBE (Methyl tertiary-butyl ether).

Is 93 available? If so I would go with that.

Steer clear of 'Speed 97' as this often contains octane boosters such as MTBE (Methyl tertiary-butyl ether).

Is 93 available? If so I would go with that.

No not even 93 is available

Only 91 and speed 97..

I filled a tankful of speed 97 .....and the improvements are very obvious...should I refrain from using this petrol ???

sort of relevant but not specific as such, just may help your understandin a bit more? anyways I found this an interesting read. Clicky

I read that just before posting.......however I'm still confused !:S

Because regular unleaded fuel is approx 88 to 89 octane ....

The only available fuels here at present are 91 and speed 97.... I dont see the sense in going for 91 as it wouldnt really be much of a difference but 97 seemed worth it !!!!.

however in double minds now as speed 97 is not really being recommended.

Given that the 91 is within the recommended octane range, I would use that.

Given that the 91 is within the recommended octane range, I would use that.

thanks! But is it worth?? .... as normal fuel is 88 octane ...does it make a big difference ???

just curious !

Edited 21 April, 201115 yr by pz1811

Engines which need unleaded premium petrol 95 RON can also be run on

unleaded regular petrol 91 RON. This does, however, result in a slight loss in

performance.

You can make unlimited use of fuel which has a higher octane number than that

required by the engine. There will, however, be no advantages gained by this in

terms of engine performance and fuel consumption.

to quote the manual !

Does this mean I'm safe using 97..??

any suggestions ?

thanks! But is it worth?? .... as normal fuel is 88 octane ...does it make a big difference ???

just curious !

91 makes a difference when compared to 88, because it is not below the manufacturer's spec. Using too low octane can cause effects such as pinging, pinking, knocking, etc. Using 88 on a regular basis is not an option - you shouldn't have been using it.

I would try a couple of tanks of 91 and judge for yourself.

Speed 97 is 91 octane fuel with buckets of MTBE added to bring up the octane.

Beware. Higher octane petrol is not 'higher quality' or 'purer', it just has additivies in it that delay spontaneous combustion under pressure, i.e. you can squash it more before it goes bang. This means that engine designers can go for higher compression to deliver more power without the embarrassment of pre-ignition or knocking damaging the engine. If your motor isn't designed for it, high octane will not deliver any benefits.

91 makes a difference when compared to 88, because it is not below the manufacturer's spec. Using too low octane can cause effects such as pinging, pinking, knocking, etc. Using 88 on a regular basis is not an option - you shouldn't have been using it.

I would try a couple of tanks of 91 and judge for yourself.

Speed 97 is 91 octane fuel with buckets of MTBE added to bring up the octane.

ive already put a tankful of '97...should i finish up the petrol and then go for 91 ?

is it safe to be changing fuels like this ?

what should I do ? :(

Edited 21 April, 201115 yr by pz1811

its a tank of fuel mate calm down.

ive already put a tankful of '97...should i finish up the petrol and then go for 91 ?

is it safe to be changing fuels like this ?

what should I do ? :(

Finish off the tank of Speed 97 and then switch to the 91. You may need a higher octane at higher altitudes.

As far as I know, high percentages of MTBE in fuel only cause problems with long term use, so no harm done. In the US, where up to 15% MTBE was used in an attempt to produce a cleaner burn, it led to the premature failure of oxygen sensors on VAG, Chrysler and other marques.

If you do continue to use Speed 97 then make sure you don't breathe in the vapour - MTBE is nasty stuff.

see http://www.hoover.org/publications/hoover-digest/article/7334 for an interesting read.

The more i seem to read about this topic the more i?m getting confused ??

manual says min RON = 95 ...

& not 91 as on tank flap !

Edited 22 April, 201115 yr by pz1811