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Do all turbos require premium?

Originally posted by: MBrown
Originally posted by: Fenixgoon
yes. me = 1.8T owner
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That sucks...I assume you have an A4 judging from your sig. How is the gas mileage?
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99 Passat, but it shares a lot of parts (or at least used to) with the A4.

i get about 29-30 highway. my brother's 02 A4 got closer to 32-33 highway, IIRC.
 
Require? No but its the recommended gas. Most will back the timing/boost down when running on the lower octane crap. Doesn't make a lot of sense to spend the extra cash on the car and insurance for the turbo though and then go and loose a good bit of the added performance. If I remember right the old 80s turbo fords even had a switch on the dash that you could flip when running low octane gas that would cut the boost in half.
 
yes
Acura RDX

My parents get 22 - 27 on milage, depends on who is driving
My mom's got a lead foot
and my dad never has to get any were on time...
 
Originally posted by: TerryMathews
Originally posted by: MBrown
Is it because of higher compression?
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Always. Octane and compression go hand in hand, whether you're talking about forced induction or not.
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LOL

For those looking to learn in this thread, forced induction cars usually have a lower compression ratio than naturally aspirated cars.
 
Originally posted by: 91TTZ
Originally posted by: TerryMathews
Originally posted by: MBrown
Is it because of higher compression?
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Always. Octane and compression go hand in hand, whether you're talking about forced induction or not.
Click to expand...

LOL

For those looking to learn in this thread, forced induction cars usually have a lower compression ratio than naturally aspirated cars.
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The physical compression ratio is usually lower, true, but with the addition of the turbo the engine functions as a multistage compressor, so the overall compression ratio between atmospheric conditions to the combustion chamber at the end of the compression stroke is higher. That is why they need higher octane. The more you compress air, the more it heats up, the more it heats up, the more prone to autoignition the mix becomes. Adding an intercooler, turning down the boost, water injection, lowering the compression ratio of the engine, and running higher octane are all measures which are taken to avoid predetonation.
 
Originally posted by: jagec


The physical compression ratio is usually lower, true, but with the addition of the turbo the engine functions as a multistage compressor, so the overall compression ratio between atmospheric conditions to the combustion chamber at the end of the compression stroke is higher. That is why they need higher octane. The more you compress air, the more it heats up, the more it heats up, the more prone to autoignition the mix becomes. Adding an intercooler, turning down the boost, water injection, lowering the compression ratio of the engine, and running higher octane are all measures which are taken to avoid predetonation.
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This is all true and should be common sense to anyone who owns a turbocharged car. However he said compression ratio, and that has a clearly defined definition.
 
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