What Octane Gas is best for Spider

[donerehart]

Fiat Team,
I have had my Spider for about a year now and have been using regular gas. Should I be using Premium?
Thanks,
don

[So Cal Mark]

not unless it pings

[donerehart]

No Ping...thanks Mark!

[redek]

Also take your elevation into account. A higher elevation effectively lowers your compression ratio, which lowers the possibility of pinging.

[4uall]

For mine it recommends an Octane level of 91 or higher (ethanol blend)

[131]

I run 110 in my 2 litre.

[sptcoupe]

If you are running 10:1 or higher CR at or near sea level, I would run 91 octane or better. Just because you don't hear it doesn't mean that you don't have detonation, and at or near that CR, you are probably at the edge, especially under load.

[124JOE]

i have rebuilt carbs for lawnmowers and snowblowers
that used regular"ethanol blend"
they were all cloged up with white deposits
i wont run any ethanol it my fiat EVER

so its premium for me

[maytag]

It's appropriate to point-out here that a higher octane reduces the likelihood of pinging because it raises the point of combustion. it SLOWS COMBUSTION. I have experienced lower cylinder pressures (therefore lower HP) on the dyno when switching to a higher octane fuel. This is not likely to be the case on a street motor, and yes, higher octane has it's place, but generally speaking, I would stick to the lowest octane rating your motor can run on without detonation (ping), and save the money.

however another good point was made. sometimes the best QUALITY fuel can only be found in a higher octane fuel. detergents, ethanol, water, etc etc etc. you'd be surprised what can be / is in your fuel.

[dom]

i have rebuilt carbs for lawnmowers and snowblowers
that used regular"ethanol blend"
they were all cloged up with white deposits
i wont run any ethanol it my fiat EVER

so its premium for me

In in some gas stations in Canada, ethonal is used to make regular into premium, up to 10% ethanol. So 91 octane does not mean no ethanol but maybe more ethanol as it can be used to raise octane rating. They do have ethanol free 91 or 94 octane at Petro Canada.

[Daniel]

Detonation can take place long before you hear ping while driving once you have ping the detonation level is at
a pretty high level this is where your pistons & rings start taking damage . I agree with Jeff about 10to1 and over
running 91 oct fuel on a street engine . If your running an engine at high RPMs in a race type of conditions these
issues will not be as aggressive if the RPM loads are above 5k .