Tesco & Fuel...

I've never seen a Tesco petrol station with Momentum 99 down here, in-fact I didn't even know it existed.

Standard Tesco petrol is awful though. Even my Slowlo hates it. It runs much better on non-supermarket petrol. (I usually use Esso) I recon Tesco petrol is US petrol in disguise. :p

RedvGreen said:
It is quite amusing. It is like if the 182 or 172 under performs Renault can just say "Ah sorry, you weren't using 98!", whereas every other manufacturer can manage to put out great figures on 95 for big super/turbo'd engines!
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You are supposed to use 98 octane in some VAG FSI/TFSI engines too. One example I know about (because I was looking into buying one) is the A3 8P 2.0 FSI. If you run it on 95 it gets noticeably worse fuel economy and a 20% power reduction.
 
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acme15 said:
You are supposed to use 98 octane in some VAG FSI/TFSI engines too. One example I know about (because I was looking into buying one) is the A3 8P 2.0 FSI. If you run it on 95 it gets noticeably worse fuel economy and a 20% power reduction.
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20%?

Back that up please.
 
acme15 said:
You are supposed to use 98 octane in some VAG FSI/TFSI engines too. One example I know about (because I was looking into buying one) is the A3 8P 2.0 FSI. If you run it on 95 it gets noticeably worse fuel economy and a 20% power reduction.
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I dont notice any difference between 95 vs 99 on my 2.0 TFSI but i always use 99 because it's supposedly better for keeping the engine clean. (FSI is direct injection into the cylinder so if it doesnt burn clean the exhaust recirculation will deposit gunk on the intake ports. It doesnt have the injected fuel going through the intake ports to keep it clean like most engines.)
 
touch said:
I dont notice any difference between 95 vs 99 on my 2.0 TFSI but i always use 99 because it's supposedly better for keeping the engine clean. (FSI is direct injection into the cylinder so if it doesnt burn clean the exhaust recirculation will deposit gunk on the intake ports. It doesnt have the injected fuel going through the intake ports to keep it clean like most engines.)
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Anyone with direct injection should use decent fuels. High octane ideally but even avoiding supermarket stuff is worth doing.

Direct injection systems can suffer from deposits significantly affecting performance/ emissions and fuel economy.
 
The deposits are mostly on the intake valves if it's an FI engine so it makes no difference what fuel you run. Unless you mean injector deposits, not sure if these are significant, rare to see petrol injector failures.

touch said:
I dont notice any difference between 95 vs 99 on my 2.0 TFSI but i always use 99 because it's supposedly better for keeping the engine clean. (FSI is direct injection into the cylinder so if it doesnt burn clean the exhaust recirculation will deposit gunk on the intake ports. It doesnt have the injected fuel going through the intake ports to keep it clean like most engines.)
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My 2.0TFSI always felt better on 99 but got worse economy than when on 95.
 
Minstadave said:
The deposits are mostly on the intake valves if it's an FI engine so it makes no difference what fuel you run. Unless you mean injector deposits, not sure if these are significant, rare to see petrol injector failures.
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Im talking about injector deposits.

They wont cause the injector to fail just create poor spray which in turn affects the operation of the engines. For example PM emissions sky rocket.

Its a big issue for Air pollution in China cities, where GDI engines are very common, but the fuel market is controlled and no premium is allowed to be charged, hence most fuels contain no additive.
 
Minstadave said:
In what way? The EGR system will dump sufficient fuel additives into the uptake side to keep the intake valves clean?
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No, poor quality combustion may lead to more exhaust soot that then recirculates and passes the inlet valve. Additives are no longer in the same chemical form once they have passed through a combustion chamber.

That said cars with sports modes to give some popping may help as they let fuel through the chamber into the exhaust, I wonder if the EGR is seeing much duty there! :D
 
Very skeptical of the benefit of higher octanes on anything bar heavily modified and tuned engines.

I've had 95RON put in N54 (two turbos), N55 (twin-scroll turbo) and highly modified 2zz-ge (supercharged) engines for months, and then months on Shell vPower (Nitro), all I noticed was 1-2MPG more. Nothing else at all.

Out of being fussy now, a tank of the good stuff would go in 3-4 times a year and no more; although that doesn't really matter now for my diesel!
 
XeNoN89 said:
My 2014 2.0 TFSI TT says 95RON on the fuel cap.
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I'm not convinced they got the fuel cap sticker right with this engine though. With the Octavia vRS which has the 2.0 tfsi a lot of them say 98 and a lot of them say 95, when they are exactly the same engine. I did read somewhere that the sticker had the wrong part code for the car, and that 98 was supposed to be on all of them. I have no idea if the newer audi ones are different to the older variants.
 
mccarf said:
I'm not convinced they got the fuel cap sticker right with this engine though. With the Octavia vRS which has the 2.0 tfsi a lot of them say 98 and a lot of them say 95, when they are exactly the same engine. I did read somewhere that the sticker had the wrong part code for the car, and that 98 was supposed to be on all of them. I have no idea if the newer audi ones are different to the older variants.
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VW have changed it's fuel ratings, everything is 95ron bar two engines.
 
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