105 Octane

[mkorgan]

We have a Sunoco gas station a few miles from the house that just installed a pump with 105 octane fuel because of a circle track raceway that shut down their pumps inside the track. Would there be any benefit in running this in my ZL1? I am thinking of getting the Roto-Fab no-tune CAI and I notice that when combined with the no-tune pulley that there was an issue with detonation based on low octane. Would this 105 octane fuel correct that? I don't drive the ZL1 every day so I could run only 105 in it if there was a substantial benefit to doing so.

Thanks for the help on this....

[The_Raging_Bull]

The good news is that all things being equal, when tuned properly E85 will make at least as much power as gasoline of comparable octane, and often a little more. E85 has a much greater latent heat of vaporization than gasoline, cooling the intake charge and thus increasing its air density-rather like intercooling or water-alcohol injection. We've all seen Sprint cars and Alcohol dragsters frosting up after a good run. Ethanol has much the same property, just to a lesser degree. On some engines the resulting power increase could be as much as 5 percent. And when we compare the performance potential of E85 apples to apples-that is, to other retail pump fuels-really there is no comparison. With a pump octane of 105 instead of 87 to 94, you can run more compression, more boost, and more spark advance without damaging the engine with knock, and make more power.

Read more: http://www.hotrod.com/techarticles/h...#ixzz2CLO8LTtU

[OldScoolCamaro]

...no need for anything like 105 octane unless you are pushing serious higher levels of modification to your engine....93 octane is quite sufficient if you are doing minor mods and upgrades. You may even foul up performance if you choose to put it in your car as such.

[mkorgan]

Originally Posted by OldScoolCamaro

...no need for anything like 105 octane unless you are pushing serious higher levels of modification to your engine....93 octane is quite sufficient if you are doing minor mods and upgrades. You may even foul up performance if you choose to put it in your car as such.

I am not disagreeing with you but the thread that was started by Roto-Fab said that they needed to increase octane to remove the knock when the no-tune CIA and the no-tune pulley were installed together. Now I would call those upgrades "minor" but based on other threads, those minor mod's required a higher octane to work well together....or get a custom tune. So, am I missing something there? Again, I am genuinely trying to understand my options.

[OldScoolCamaro]

...to get a clear answer to your question I would refer you to contact roto-fab if that's whose post you are inquiring about. I feel there may be some disconnect between the information posted and digestion of same.

[Deke736]

Originally Posted by mkorgan

I am not disagreeing with you but the thread that was started by Roto-Fab said that they needed to increase octane to remove the knock when the no-tune CIA and the no-tune pulley were installed together. Now I would call those upgrades "minor" but based on other threads, those minor mod's required a higher octane to work well together....or get a custom tune. So, am I missing something there? Again, I am genuinely trying to understand my options.

I think the thread you are referring to is this one:

http://www.camaro5.com/forums/showthread.php?t=259566

Ted states that if you go with the 10% pulley and the Roto-Fab intake that it needed 97 octane to avoid pulled timing and codes. There is even some benefit with the 5% pulley in race day situations. I would think you could mix the 105 (assuming it's unleaded- I didn't see you mention that) with 93 to get 97 octane. I don't think there would be a benefit to running 105 all the time or even at full strength.

[mkorgan]

Thanks for the help. I think I will play it safe and just stay away from it for now.

[hognutz]

Originally Posted by mkorgan

We have a Sunoco gas station a few miles from the house that just installed a pump with 105 octane fuel because of a circle track raceway that shut down their pumps inside the track. Would there be any benefit in running this in my ZL1? I am thinking of getting the Roto-Fab no-tune CAI and I notice that when combined with the no-tune pulley that there was an issue with detonation based on low octane. Would this 105 octane fuel correct that? I don't drive the ZL1 every day so I could run only 105 in it if there was a substantial benefit to doing so.

Thanks for the help on this....

there is no little benifit on a stock car or a car with or one with just a rotofab intake.

the 105 would give you results on a car with added boost and no retune.

there are cheaper ways than 105 though.

rule of thumb is the least octane that does not detonate is the best. 105 is overkill for what you describe. Octane is not a more is better type of thing. read up on it.

I think E85 is around ~101 octane but it has less btu's so it milage is worse. It would also require a retune. stoichiometric on gas is 14.7:1 and on E85 it is like ~9.7:1 I think

the beauty of e85 is the fact is is cheap 101 octane and burns cool.

[mkorgan]

Originally Posted by hognutz

Octane is not a more is better type of thing. read up on it.

I am fairly familiar with octane as it relates to performance in my older Camaro's. I use 107 octane in my 81 but it has an old school big block and won't run properly on anything less. Again, I was just concerned of the need to increase octane with the CAI and pully mods. I am old school from an engine technology perspective and am trying my best to get up to speed on these engines with SC's / MAFs / and computer controls timing, spark, etc..etc.

Thanks again for your willingness to help me. Much appreciate.

Mike

[hognutz]

Originally Posted by mkorgan

I am fairly familiar with octane as it relates to performance in my older Camaro's. I use 107 octane in my 81 but it has an old school big block and won't run properly on anything less. Again, I was just concerned of the need to increase octane with the CAI and pully mods. I am old school from an engine technology perspective and am trying my best to get up to speed on these engines with SC's / MAFs / and computer controls timing, spark, etc..etc.

Thanks again for your willingness to help me. Much appreciate.

Mike

In the case you were referring too octane was needed because of the stock tune not being able to compensate for the mods. It would get very expensive in gas to do it that way. But you could.

Once you mod that far I think I will just retune the car and run 92 octane. On you big block the engine design is just less tolerant of compression and needed that octane.

[69NMYSS]

U can buy a 5 gallon bucket of Torco for about $250 (race gas concentrate) which would give you about 25 tank fill ups at 97 octane (after adding Torco) with base octane of 91. I am doing this with my Roto-fab CAI and 10% OD pulley to avoid tuning and voiding warranty.

[jlbabb]

We have a gas station that sells it at the pump for our local circle track as well & you have to be careful because the gas at our station is leaded. Runs good in my 69 Camaro & my 66 Chevy II but not in the late model cars. It will melt the cats.

[rjbuck]

Originally Posted by lgvenable

The good news is that all things being equal, when tuned properly E85 will make at least as much power as gasoline of comparable octane, and often a little more. E85 has a much greater latent heat of vaporization than gasoline, cooling the intake charge and thus increasing its air density-rather like intercooling or water-alcohol injection. We've all seen Sprint cars and Alcohol dragsters frosting up after a good run. Ethanol has much the same property, just to a lesser degree. On some engines the resulting power increase could be as much as 5 percent. And when we compare the performance potential of E85 apples to apples-that is, to other retail pump fuels-really there is no comparison. With a pump octane of 105 instead of 87 to 94, you can run more compression, more boost, and more spark advance without damaging the engine with knock, and make more power.

Read more: http://www.hotrod.com/techarticles/h...#ixzz2CLO8LTtU

I sent Fbodfather a PM about E85. He told me it would damage the fuel system.