Euro95 and 98

[SPEEDKILLAR]

The reason I opened this thread is because 2 days ago my friend put Euro 98 instead of 95 in his E36 3.28 coupé, what the car was originaly made for.
He says its for better performance. :roll:

But I am from opinion that its bad for the engine on long term, because it may have some different additivs.

I wanna know more about this, like differences and how it effects an petrol engine?

What do you guys think?

[Wutputt]

It's defenitely not bad for the engine to put 98 RON into it instead if 95 RON. Actually it's better. But unless you have a really high performing engine, it isn't worth the price tag. On a normal engine the gain in performance is almost none.

The higher the octane number, the higher the knock resistance of the fuel (it doesn't self-ignite as easy). Modern petrol engines have a knock sensor. The engine will alter the ignition advance so the engine will run on the knock limit. The higher octane number the fuel has, the more ignition advance the engine can take. Raising the ignition advance theoretical means a (not that much) higher combustion pressure, thus more power.

But those differences are really small. I would only put high octane fuel into my car if I had a turbo engine running on high boost or a high performance engine with a high compression ratio.

[gottacatchup]

actually running too high of an octane can cause you're engine to missfire. Because the fuel is harder to ignite in engines designed for low octanes a higher octane fuel can cause missfires and actually lower performance.

Either way putting one tank of higher octane fuel into your car will cause no long term harm.

[SPEEDKILLAR]

Thanks guys, so it had its advantages and downsides.

But like you said, the gain in performance isn't that big, so why waste more money and on the long term cause harm to the engine.

[ARMAN]

Dont know much about engines/petrol things but as my father said some time ago(10 years back) its not good for engine. I got a full tank of that 100 octane V-Power 2 times, as they say it helps to clean engine so it runs better then. Dont know how much truth it is.

[SPEEDKILLAR]

^^^^ Yeah I have heard about that, you've got all lot of these product to clean the engine.
I'll look up some information about it, how effective they are and I'll try it myself.

[Wutputt]

Dont know much about engines/petrol things but as my father said some time ago(10 years back) its not good for engine. I got a full tank of that 100 octane V-Power 2 times, as they say it helps to clean engine so it runs better then. Dont know how much truth it is.

In Germany a Shell V-Power test has been done on a VW Golf FSI (i.e. a direct injected petrol engine). A power gain of 9% was measured compared to normal 95 RON, and a gain of 1% compared to 98 RON. Keep in mind this was done on a petrol engine with direct injection designed to run on 98 RON. You won't have those gains on a normal petrol engine with indirect injection.

Shell states V-power will drop in cylinder friction between the compression ring and the cylinder by 2%. But I haven't read any tests confirming this until today.