91? 93? Would we get an increase in HP if we used 100 octane?

 

91.

No, you'd lose power using 100.

 

The 330 HP rating used in advertising is an estimate of engine horsepower, not actual dynoed horsepower to the wheels It's not realistic to expect that from your car without serious modifications (more than common bolt-ons).

 

What? You can definitely expect ~330 HP w/o modification...

OP- the 330 HP rating is also 330 HP at the engine, it loses a decent amount between the engine and the wheels...I guess if BB meant 330 HP at the wheels, then yes you'll need significant modding to get that

 

That is precisely what I meant, as all of us are dynoing cars on a chassis dyno and not an engine dyno. I have yet to see anyone post engine dyno numbers on the forum that I've noticed. I also have yet to see anyone post a 330 HP dyno sheet with only bolt-ons and a tune unless I've missed it. I thought that what I was saying was crystal clear, perhaps not.

 

I understood what you meant BB, I just wanted to make sure the OP was clear on it, I didn't know if they were clear on it just based on the question.

 

Yes, i meant the advertised 330 hp which is from the engine not wheels.

I just figured i'd mention the 330hp because everyone gets different chassis dyno numbers.

In any case, it doesnt really matter what number i meant, i was just curious if there would be ANY horsepower gains just from pumping 100 octane.

I ask because I've seen some ECU reflash descriptions and some other engine mods that actually say something like: 200hp stock, 210hp w/91 octane, 215hp w/93 octane, 225hp w/100 octane... along those lines.

 

Higher octane is used in some of the turbo application dynos that have been posted. The higher boost pressure it what delivers more horsepower, the higher octane gas is used to prevent detonation at higher boost pressures.

 

Formula 1 cars operate on very high octane fuel even though they're not turbo'd

 

Octane level simply is a measure of how fast a certian gasoline will burn. More specifically it measures the ability to prevent predetonation or knock. It does this buy having a higher flash point and takes more compression or heat to ignite. Technically high octane fuel has lower energy. Most modern 'perfomance' engines operate at a higher compression rate inside the motor. Basically it means you can compress the gasoline more, before it will ignite. Lower octane gasoline actually has higher engergy levels and will ignite easier. Putting this in a high compression motor will cause the cylinder to fire early, out of sequence of the stroke, causing a pinging noise. This effect will severly limit the life of a car.

So will higher octane gas help your car? Not in the slighest. Higher octane gas actually has the same density as lower octane gas. So adding a higher octane gasoline will not add any extra hydrocarbon content or oxygen to your engine. Your power output levels will not be affected at all.

The reason you see others getting more power out of high octane gas is due to custom tuning efforts. Your timing referes to the point in the crankshaft angle when the spark plug fires, or ignites the gaoline. So higher octane fuels allow you to compress the gasoline more before firing. Combustion actually commences while the piston is on its upward journey. The time it takes for the flame kernel at spark plug to expand to the top and sides of the chamber permits the piston to pass top dead center before it receives the flame front. The expansion of the gasses during the period from ignition point to flame front reception (top dead center) increases the volume in the chamber and effectively creates higher compression.

So advancing the timing with custom tunes can effectily create higher compression in your engine, which in turn requires higher octane fuels. That is why some custom tunes use different fuel maps with higher octane gasoline.

 

Exactly which F1 teams posted their dynos here?

Don't be a confusing azz, I tried to give a simple, easy to understand answer to a legitimate question.

And they used to be turbo'd not so long ago and used high octane fuel then too. Not that this has anything to do with anything.

 

hey no fighting staff. set an example. Sam I am very disapointed in you.

 

F1 is going back to turbo!

Seriously.

 

haha I was just pulling your leg

 

You wacky Arab!