I found this gas station near my house which sells 100 octane gas for approx $5/galon. The question is whether anything can get damaged in the engine. In Europe the normal high octane number is 98 so this is only 2 above that. The ECM should adjust fine to the new octane level but I'm still worried. The only mod on the engine is the aircharger kit from K&N. The car is a 1999 C2 6-spd with 56,000 miles. My tank is almost empty so quick responses are appreciated

I have heard that it really depends on how they make that fuel get to 100 octane... if they use certain additive to boost the octane (which is common) the additive can eat away at seals in modern cars.

that is just what i heard.

Who's 100 octane is it? Most use toluene to achieve the higher octane. I don't think it will hurt your car and it shouldn't ruin any seals...plenty of folks run this. You will not really be able to take advantage of the higher octane...as your ecu would need to be tuned (and for an NA car...just not a lot to gain). I would mix the 100 with the 91 to run 95-96...BTW Europeans use RON (research octane)...in the US we use (R+M)/2....also known as PON...pump octane (M being MON...motor octane)...so they are not equivalent.

+1 on what Statman said.

i wouldn't fill it up with 100 octane. that's just wasting money.
but who am i kidding, i'm paying $5 for 91 in sunny california.

If your looking for 100 Octane, i would not get it from a pump station...god knows how long its been in there or what it is...i use HP fuels they ship right to my door

Sunoco GT100 all the way

http://www.goestores.com/home.aspx?Merchant=highfuelsn

I have Sunoco 100 up the street. Im tempted to try!

Why not try half 91 octane and half 100, see what you think...

you only benifit from running higher octane if you want to run more boost so you dont detonate. otherwise on a N/A car 91-93 pump is sufficient.

It does help. I use Sunoco 98 (100) and it makes a significant difference. I just filled up before my last autox and it was now $8/gal. It's worth it, I got FTD! Some of what is said in previous posts is true, however no one mentioned the fact that 91/93 has ethanol and in winter is oxgenated. That lowers the BTU (or power potential) of that fuel. The race fuels do not have ethanol added, hence the power difference you can feel. Don't be afraid of pump gas if you buy it from a reputable source like Sunoco. Good luck.

PS - more/higher octane is not better - I would refarin from 105 race fuel.