Škoda TSI octane requirements 95 or 98?

[backdoc]

In this weeks local "Free Press Leader". I'm sure that it will be syndicated in all their various publications.

Distinctive character

by Peter Barnwell

"This is a really good car, the right size. plenty of go, sporty handling and feel and, after a recent makeover, good-looking too.
Skoda's Octavia RS TSi, (the turbo-petrol model) is in a competitive section of the market but measured against direct competitors like the Mazda 6, Honda Accord EURO and new Subaru Liberty Sport. The Czech-made five¬door lift back blows them all into the weeds in more than outright performance.
It runs a two-litre, turbo-petrol four-cylinder we know and love from the previous VW Golf GTi and is good for 147kW/280Nm output. That translates into a 0-100km/h sprint in 7.3 seconds.
Response on the move is impressive, aided in the test car's case by an optional double clutch (DSG) transmission with steering wheel paddle change -a $2,300 option on the base price of $37.990.
Equipment levels are generous and include a premium audio system, sports seats, dual-zone climate control. auto wipers and headlights. auto dim rear view mirror, six airbags and stability control.
It handles the way a sports sedan should, offering a taut feel and minimal body roll through turns, strong brakes and quick steering. The smooth-running engine with a bit of a burble is a gem, with as much squirt as any normal person could need and returns 7.7 litres/100km into the bargain -on 95 octane fuel.
The Octavia RS feels nimble and safe to drive. The body is rock solid and practical with the liftback rear and split-folding rear seats.
It's a largish car providing seats for five, four in comfort. and a large load area.
The driver's cockpit is stylish and functional. Essentially, Skoda's Octavia RS TSi is a keener priced VW with its own distinctive character. Definitely worth a look."

You can currently view the story on the Free Press Leader site by clicking on the "Browse the entire paper online" link. This will of course only work this week until a new edition comes out.

Bit of a shame they neglected their research. It's the same engine as the new GTI, just the same power outputs of the old engine, albleit on 95RON instead of 98 & improved fuel efficiency.

[woofy]

I still don't get why some RS are seemingly set up to run 98, mine definitely has 98 in the door with 95 in brackets as a fallback.

[Antiplastix]

Mine has 95 on the fuel filler cap. But the local BP only sells 98 anyway.

[backdoc]

I still don't get why some RS are seemingly set up to run 98, mine definitely has 98 in the door with 95 in brackets as a fallback.

is yours a pre-FL? I know the old GTI engine required 98, the new engine is 95, but plenty of people seem intent on running 98. I can't see the value in it myself if the engine was tuned for 95.

[TuNeS]

the difference in price between 95 and 98 is nothing. you buy a nice car with a performance motor.....fill it with 98.

[backdoc]

the difference in price between 95 and 98 is nothing. you buy a nice car with a performance motor.....fill it with 98.

I had a MkV R32 and it never went without 98. But that was the specification. If the engine was tuned to run on 95, why use 98? Does it give you that warm fuzzy feeling inside?

Find some evidence that shows it is going to give performance or economy benefits for thie particular engine, then I'll listen. I just believe it is marketing hype!

[Manaz]

I used to work with Peter Barnwell - Barnie knows his cars, it's good to see he's impressed with the Skoda!

[Manaz]

I had a MkV R32 and it never went without 98. But that was the specification. If the engine was tuned to run on 95, why use 98? Does it give you that warm fuzzy feeling inside?

Find some evidence that shows it is going to give performance or economy benefits for thie particular engine, then I'll listen. I just believe it is marketing hype!

Most modern cars have an ability to vary their tune dependant on the fuel quality (not directly, but rather by monitoring for knocking and adjusting timing to suit the quality of the fuel they're burning). So running RON98 fuel can indeed have a benefit.

[backdoc]

Most modern cars have an ability to vary their tune dependant on the fuel quality (not directly, but rather by monitoring for knocking and adjusting timing to suit the quality of the fuel they're burning). So running RON98 fuel can indeed have a benefit.

I guess the point of this is - what is the benefit going to be? Not the perceived benefit, not the marketing of these fuel companies, but the real world benefit?

How will it improve my driving experience, how will it protect my engine, how will it save me money etc etc

[dazag]

I had a MkV R32 and it never went without 98. But that was the specification. If the engine was tuned to run on 95, why use 98? Does it give you that warm fuzzy feeling inside?

Find some evidence that shows it is going to give performance or economy benefits for thie particular engine, then I'll listen. I just believe it is marketing hype!

OK, the hype behind higher octane fuels.
- Less prone to detonation ( if you run a performance Turbo motor or high compression motor, detonation is a really bad thing, so to protect against it, you need to run higher octane fuel)
- depending on the company, the higher octane fuel is generally better quality ( more consistent Octane rating ) and burns cleaner. which means less contaminants in the oil and less carbon build up.
- 98 rate fuels are generally have a higher density, which means more "bang" for your buck, that's why you get better fuel mileage. The car doesn't need as much fuel to burn to get the same amount of power.

Generally I'e found that BP have the purest form of 98 fuel (Ultimate), as it contains the least amount of benzines etc. Jump on the sites and check out the MSDS sheets for each fuel, it will give you density's and what it contains etc

Run what ya want people, it's your car, if you think the fuel companies are just hyping it up, then put what ya want in your car and be happy with your choice. If you run a Turbo'd or high compression motor and you run 91, or possibly some 95 rated fuels then you could be doing damage to your car with out even knowing. Yes I know cars have "anti'knock systems on them, and that's when you'll feel the power drop off to protect the engine...........but why buy a performance car to only have it run at 95% of it's efficiency/power??

My work car is a typical Ford Falcon, and it only see's 91 as it has a very stock motor, and due to that i dont get to see much benefit in performance or economy from slipping in 95 or 98, although it does run better on 98 ( drives smoother etc)

I'm looking forward to when BP bring out the BP Ultimate diesel with it's higher cetane rating. The Skoda RS TDI will be living on that stuff if it makes it to NSW servo's

[woofy]

Mine is pre FL, as are most on here, but others from the same year have 95 as the min. I've never found out why, as I found it said 98 in all my research before buying the car.

[Graybags]

Having a modified Dyno tuned turbo engine with knock monitor for the past 8 years I can tell you that it knocks with anything less than 98. We took our cars to Tassie a few years ago (WRX car Club) where they only had 95 and we had to add octane booster to stop even stock engines check engine light coming on with high engine load. Agree with the last caller for piece of mind and maximum performance why not the extra $ for 98?

[backdoc]

OK, the hype behind higher octane fuels.
- Less prone to detonation ( if you run a performance Turbo motor or high compression motor, detonation is a really bad thing, so to protect against it, you need to run higher octane fuel)
- depending on the company, the higher octane fuel is generally better quality ( more consistent Octane rating ) and burns cleaner. which means less contaminants in the oil and less carbon build up.
- 98 rate fuels are generally have a higher density, which means more "bang" for your buck, that's why you get better fuel mileage. The car doesn't need as much fuel to burn to get the same amount of power.

Generally I'e found that BP have the purest form of 98 fuel (Ultimate), as it contains the least amount of benzines etc. Jump on the sites and check out the MSDS sheets for each fuel, it will give you density's and what it contains etc

Run what ya want people, it's your car, if you think the fuel companies are just hyping it up, then put what ya want in your car and be happy with your choice. If you run a Turbo'd or high compression motor and you run 91, or possibly some 95 rated fuels then you could be doing damage to your car with out even knowing. Yes I know cars have "anti'knock systems on them, and that's when you'll feel the power drop off to protect the engine...........but why buy a performance car to only have it run at 95% of it's efficiency/power??

My work car is a typical Ford Falcon, and it only see's 91 as it has a very stock motor, and due to that i dont get to see much benefit in performance or economy from slipping in 95 or 98, although it does run better on 98 ( drives smoother etc)

I'm looking forward to when BP bring out the BP Ultimate diesel with it's higher cetane rating. The Skoda RS TDI will be living on that stuff if it makes it to NSW servo's

If the fuels were the same price, then yes, "bang for your buck" applies, but when you're paying more "buck" for your "bang", then I'm no expert, but that doesn't seem to make fiscal sense.

Like I said, happily put 98 in a car designed for it, just don't believe in putting 98 into a car designed to run on 95. But that's the beauty of a democratic society, you can use what you want!

[Antiplastix]

Out of interest,my 2008 Triumph Street Triple with filter mods,Arrow 3>1 and a Power Commander III with custom map ran basicly the same figures on 91 as it did on 98. I think you will find that post modern FI engines will adjust down for lower ron fuel but you dont gain anything by putting in a higher octane than it is tuned to run on. The higher the compression level of the engine the higher the octane needed for the motor, this gets confusing in force inducted motors as their static compression is differant to their pressurised compression.

[dazag]

Backdoc - yep you're right, you do pay more for the extra bang, but I should have worded that a little differently though to get across what I was talking about.
And yes you are right, if you have a turbo'd skoda that is tuned and designed to run 95, then there is no need to run 98 if you leave it in Stock trim. But if you ever decide to tweak the settings (especially with turbo boost settings) then fuel requirements will change, purely to ensure the engine doesn't detonate.

Antiplastix - with the PCIII , Did you play with it when running the different fuels to get the best out of each?? What fuel/air ratio did you have set up through the rev range and did you play with the ignition timing at all??
If you didn't play with the set ups when running the different fuels then I'm not surprised that the figures didn't change (assuming you're talking about dyno runs??)

All I'm saying is that if you have a stock car that says to run on 95 then that's fine, but if you have a car that says to run on 98, then make sure you do because there is either a compression difference or a boost difference between the engines and if you run a lower octane fuel then you can risk doing damage to the motor - it might not cost you now, but give it time your engine could be up for a rather hefty repair bill.

I wont go into the new E85 fuels you can get in some places (or the Shell V-power R 100 octane ethanol boosted fuels) , but to say a mate who has a very tweaked up Nissan GTR has had his car re-tuned (only fuel mapping as E85 runs leaner) to run E85 and got more HP & torque at the wheels, but again he wasn't tuning for efficiency.