is premium fuel really needed?

[turbo88stang]

ive built my fair share or cars with forced induction and high compression, and was just wondering if 91 octane is really needed for 9.6:1 compression, especially if the stock tune isnt very generous with timing?

[Rocman]

Why not get a better tune and use premium?

[ARIZONA SRT-10]

With forced induction on the Viper.....91 is the least you should use......detonation will KILL your motor! 20 cents more per gallon than 87 octane is cheap insurance....

[BAD68GTO]

A lot of factors go into this like what motor? Cam? Initial+centrifical, et cetera..... I am running 10.69 with a 108 centerline and 302 @ .050 duration on 93 premium and no boost okay, but that is a hell of a lot of overlap in the cam. On a Viper or something higher end where you can't afford or don't want to buy, when in doubt, go with more octane unless you have a quiet exhaust and you can hear the ping easily. I could type on this thread's subject for hours alone, but you are a noob and you might be refering to your Civic and that I don't want to touch Forced induction on a Viper with 91 octane?????????? PLEASE give me your VIN Arizona so I don't buy your Viper by mistake in the future...

[Doug at RSI]

Repeat after me: Running the right fuel is just like changing your oil on time or before and after track events; cheap insurance.

When spending so much on a focused sports car I can't think of any reason that would justify running less than high octane. A lot of guys I know even keep a barrel of C16 or 109 in their garage.

[The Former PFR]

Originally Posted by Doug at RSI

Repeat after me: Running the right fuel is just like changing your oil on time or before and after track events; cheap insurance.

When spending so much on a focused sports car I can't think of any reason that would justify running less than high octane. A lot of guys I know even keep a barrel of C16 or 109 in their garage.

Exactly

[GTS Dean]

Originally Posted by Doug at RSI

Repeat after me: Running the right fuel is just like changing your oil on time or before and after track events; cheap insurance.

Have your oil analyzed after track events for $15 and save yourself $50 in unnecessary synthetic oil and filter cost.

[Danko]

So how actually would lower octane hurt the engine? What physically would happen to cause damage?

[BAD68GTO]

Try the search feature, on Google, and learn how engines work and how detonation can hurt engines.

[racinfarmer]

Originally Posted by Danko

So how actually would lower octane hurt the engine? What physically would happen to cause damage?

Octane is the measure of resistence to detonation in fuel. A lower octane with pre-ignite in your engine and ruin only the piston and rings if you are lucky. It is also know as engine knock or ping. Very common in my racing snowmobiles. 2 octane points off and I'm rebuilding the top end. As short Google search comes up with this picture of pre-detonated pistons.

[b3rndtt0ast]

[racinfarmer]

Had to get to 5 posts to post the image.

[triblk6spd]

Are we really having this conversation? This is the kind of shit that is being discussed over at hondaforums not Viperalley. Put in the good gas and call it a day.