PROOF that 93 octane produces more HP then 87

[Matt G]

to anybody that argued with me about 93 not producing more HP then 87... [img]graemlins/slap.gif[/img]

look at this dyno chart and tell me that 93 octane doesn't produce more horsepower then 87

http://www.hypertech.com/get_dynocha...359277&tp=jpeg

[blacksport]

93 allows more timing.

[98Camaro3.8]

That's not because of the fuel, it's because of the timing advance in the HPP. Like blacksport said, the higher octane fuel allows for more timing advance, but the fuel itself doesn't make any more power. Changing the tune adds power, changing the fuel doesn't (assuming the car is running properly).

That's also propaganda that has no truth in real life.

[Matt G]

so 93 octane allows the opportunity for more horsepower but you are saying just running a car on 93 octane won't increase the horspower vs. running 87?

I can't wait until next season.. I know there is a difference in my car between 87 and 93

[98Camaro3.8]

Originally posted by Matt G:
you are saying just running a car on 93 octane won't increase the horspower vs. running 87?

Yes, that is correct. Assuming your car is running like it should, you will not get a single extra horsepower from running high octane fuel.

If your car has problems, it may be experiencing detonation which would cause a timing retard. If so, high octane fuel may alleviate the KR and increase power slightly, but it wouldn't be any more power than a normal car on 87.

Going to move this to General Tech...

[FunkZ]

If the car will run perfectly fine 100% of the time without any KR on regular 87 gasoline, then why did GM put knock sensors in the car?

The truth is, detonation can occur even in a perfectly tuned car due to variations in temperature, engine load and gas quality. And knock will result in a loss of power due to the computer retarding the timing. Just because you don't hear pinging doesn't mean the computer hasn't detected the knock and pulled timing before you ever notice a thing.

Running higher octane gas in your car may not be necessary in every situation, but for the small price difference, isn't it worth it to assure your car is always running at it's peak performance?

[98Camaro3.8]

Originally posted by FunkZ:
If the car will run perfectly fine 100% of the time without any KR on regular 87 gasoline, then why did GM put knock sensors in the car?

Because like you said, sometimes you get bad gas or extreme temperatures. But under normal conditions you shouldn't be seeing any KR. You're saying that it's normal to be driving around all the time with KR? You should only occasionally see KR under bad circumstances.

Originally posted by FunkZ:
but for the small price difference, isn't it worth it to assure your car is always running at it's peak performance?

My opinion, no. Because it should only rarely run at less than peak performance, and even then it should only be temporary.

[FunkZ]

Well, I disagree. When are you most likely to see KR? In conditions when temperatures are higher and the engine is under extreme load. As in at full throttle at a drag strip?

If you drive your car like grandma around town all day long then yes, 87 is all you will ever need.

[mwh27]

That dyno graph is by no means PROOF that 93 octane makes more HP than 87.

A simple google search and a basic understanding of chemisty/physics should lock this thread.

http://en.wikipedia.org/wiki/Octane_rating

It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. Using a fuel with a higher octane lets an engine be run at a higher compression ratio without having problems with knock. Compression is directly related to power (see engine tuning), so engines that require higher octane usually deliver more power. Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane gasoline. It should be noted that the power output of an engine also depends on the energy content of its fuel, which bears no simple relationship to the octane rating. Some people believe that adding a higher octane fuel to their engine will increase its performance or lessen its fuel consumption; this is mostly false—engines perform best when using fuel with the octane rating they were designed for and any increase in performance is minimal.

[ November 10, 2005, 01:25 AM: Message edited by: mwh27 ]

[rhouse21]

Originally posted by FunkZ:
Well, I disagree. When are you most likely to see KR? In conditions when temperatures are higher and the engine is under extreme load. As in at full throttle at a drag strip?

If you drive your car like grandma around town all day long then yes, 87 is all you will ever need.

There is a simple message here. If you're really concerned that hard driving will make your engine knock, When you see yourself going to the track or out for a weekend of hard driving, use 93. What the hell, throw in a can of octane booster on top of that for good measure. When your're done and are just farting around town, use 87.

Remember, the whole point of high octane is to make the gas more stable under high temps & pressures. If your engine isn't seeing at least one of those factors, the extra stability is just wasted... unless your engine has been tuned to take advantage of that extra octane.

Just putting Z-rated tires on your car won't make it able to reach 149+ mph. Similarly, just using higher octane won't give your car extra hp. Your car as a mechanical system must be set up to take advantage of the extra capability being given to it.

[FunkZ]

Heh, well I don't know about anybody else, but I like to drive my car. This is not to say that I go around driving 100mph everywhere I go, but I am standing on the throttle on a daily basis. I like snapping the rear end around, catching second, and howling through the turns on country back roads. I spent a good bit of money to make my car more fun to drive, not just to putz around town. And I can tell you from years of experience that if I tried to run 87 octane gas in my car under my daily driving conditions, I would get knock. Hey, believe me, if I could run 87 and get the same performance I would gladly do it because I'm all about saving money. But the truth is it just isn't the same without the high octane.

[Rowdy Burns]

let the man waste his money on 100 octane.

[shenanigans]

Dude your car is not running right...

My 3.4L ran just fine on 87, evne hold ths record at the moment.

my 3.8L runs just fine on 87, pulled some good times for itself as well...


I coudl give you the list of my drivetrain components that I have replaced in the 7 years on my cars, if you want me to prove I do not drive like a grandma.


PS, if anything at the track my car doesn't see extreme hot temps, it sees it more on the street, I very very very rarely ever see knock and if I do its 1* or less, when I run 87, and know what I get it with 93 octane too... believed to be something wtih torque management.

what plugs are you running?

[FunkZ]

I've been running AC Delco Rapidfires.

I'm talking about the difference between 87 and 93 pump gas in a relatively stock vehicle.

Now when you're talking about race gas, you do realize don't you that there are properties other than just octane rating that give race gas better performance qualities than regular pump gas, even in a stock engine car?

http://www.vpracingfuels.com/vp_01_f...7C8135F545C46#

I regularly go to Summit Point and watch my friends race their motorcycles. They all use race gas in their stock engine bikes, which only call for 92 pump gas. So you're saying that they're all wasting their money on far superior fuel than what is available at the pump?

[shenanigans]

Originally posted by FunkZ:
I've been running AC Delco Rapidfires.

I'm talking about the difference between 87 and 93 pump gas in a relatively stock vehicle.

which plug, might try a range cooler...

as for relatively stock vehicle?

your 3.4L has more mods then my 3.4L had.

my 3.8L only had free mods.