octane

[RS/SS '10]

Originally Posted by Iron Lung Jimmy

Weren't they using a carbureted engine?

Yes they did

[Iron Lung Jimmy]

That's what I thought.

That's a completely different animal than an EFI engine.

[pyroguy]

E85 on a boosted engine will make way more power than 93. However, on a NA build, E85 vs 93 will make very little difference. If Engine Masters did a NA comparison that could be why they didn’t see the gains.

[hudson773]

Originally Posted by Iron Lung Jimmy

That's what I thought.

That's a completely different animal than an EFI engine.

air fuel ratios don't change because of intake method. the optional ratio was reached, carb or inj, no diff

[gtstorey]

By Fuel Injection I think they are really talking about the full computer controlled engine management system, and in particular the ability to control firing in much greater detail and run closer to a limit of knock without going over.

Octane doesn't add power, but does allow you to get more power from an engine by allowing you to run different limits.

[FasNuf]

Higher octane allows you to advance timing to get to MBT without being limited by knock.

[hudson773]

Originally Posted by FasNuf

Higher octane allows you to advance timing to get to MBT without being limited by knock.

not true, all the tests showed about 21' was optimal for all the fuel grades from 87 regular to 120 racing fuel

[FasNuf]

Originally Posted by hudson773

not true, all the tests showed about 21' was optimal for all the fuel grades from 87 regular to 120 racing fuel

21 degrees is not optimal for all engines on all fuels to reach MBT. You can’t get more torque than maximum. If this was the case, there would be no need for the hook test. Everyone would just run 21 degrees.

[gtstorey]

Originally Posted by FasNuf

21 degrees is not optimal for all engines on all fuels to reach MBT. You can’t get more torque than maximum. If this was the case, there would be no need for the hook test. Everyone would just run 21 degrees.

And probably not even for all RPM on the same engine.

[NOT A 45]

I don't believe he understands the principles of ignition timing or even why it varies. There is no optimum, and it's relative to engine speed and load. When our cars detect spark knock, the first thing the ecm does is back off ignition timing to eliminate it. Octane plays a major role in when that occurs!

[Royal Tiger]

I can’t figure out why he’s so defensive over some stupid internet clickbait. If you want to run 87 in your SS knock yourself out. E85 DOES make more power (on modded engines) and there are tons of videos proving it in real life.

[NOT A 45]

Originally Posted by Royal Tiger

I can’t figure out why he’s so defensive over some stupid internet clickbait. If you want to run 87 in your SS knock yourself out. E85 DOES make more power (on modded engines) and there are tons of videos proving it in real life.

E85 will make more power on any engine even a stock one because it's rated at 120 octane. So like I said above, the ecm will not remove ignition timing because there will be no spark knock. Other advantages are cylinder cooling, and ethanol is 1/3rd oxygen.

[FasNuf]

Originally Posted by gtstorey

And probably not even for all RPM on the same engine.

Thats for sure. Look at the low or hi octane tables and the numbers for low rpm low load are much bigger than hi rpm hi load

[CamaroCracka]

Save 40 cents a gallon to put the pistons in the oil pan, I'll pass. More octane reduces the chance for detonation. I don't need a YouTube channel to tell me this. I've seen it in person. Hell, I had a buddy with an LS1 Z28 in 2001 and his girl friend put 87 in and it sounded like it was going to come apart. Took it to the gas station and filled it with premium and it ran a lot better. Seen other examples of performance motors running like crap on lower octane fuels. There are probably other videos on YouTube that say the opposite.