My CB VS. 3000gt SL

[LinX]

3000gts are not soo fast so there is a good chance of keeping up with one and maybe even beating it. As for the octane story...sorry man, I just don't see how your engine can gain the horses. Compression ratios should mean something..

[owequitit]

BTW owequitit, I believe the purpose of the knock sensor is more for cars that require high octane fuels as a safety feature; say if someone got a bad tank of gas or was only able to fill with lower octane fuel. To the best of my knowledge, I don't think most ECUs will be more agressive with higher octane that recommended fuels, at least stock. Certainly when we talk tuning, many people have a tune done for race gas and another for pump gas allowing optimal performance with either type of fuel.

I did enjoy your explanation of octane and how it can (and will) adversely affect performance

That was just kind of the basic gist. I think to an extent that is true, but I am not sure about some of the new cars.

For instance, the J30A4 in the new Accord V6s. It is rated based on output with 87 octane, but it seems to lay more down on the dyno when it is running on 91. That would seem that it is indeed advancing timing with fuel quality increase.

The K series seems to do the same thing.

With the older cars, such as the H22, I am sure it was mostly a safety feature, but with the increasing HP of ECU's, you will probably see more output on better gas, as the computing logic improves.

[quickangel93]

i should just make a movie to prove you guys wrong. maybe next week or so.

btw even by the stupidity questions on any forum, this is probably the worst flammed forum there is. come on guys, even civic guys barely flame, here its everyday!

[owequitit]

i should just make a movie to prove you guys wrong. maybe next week or so.

btw even by the stupidity questions on any forum, this is probably the worst flammed forum there is. come on guys, even civic guys barely flame, here its everyday!

If you think there is a lot of flaming here, you should probably go hang out on Accordingly Done or Honda-Tech. They are WAY better.

Also, as I said previously, you are more than welcome to prove us wrong. I await the video.

Of course, video at the track would probably be best, because then we would be able to quantify what we are seeing, because the large difference it ET's would show us.

Oh, and to avoid temperature/climate variables, you should run them all on the same night.

[NAiL05]

Yesss I want to see the video too. Aint no lies on the track its all driver and its pretty even and safe.

[J-specCb4]

Sorry, BS Even a stock SOHC 3kgt puts out 220hp the DOHC is putting 260hp. Even badly tuned with a ricer driver is gonna pwn our cb's stock. Shit the vr4 could be running on 4 cylinders and still pwn a stock cb.

dohc is 220 and heavy as all shit... i beat my boys sl in my cb... shouldnt have but i did he couldnt drive when he first got it

[TheNextAZN]

hmmm.. no body mentioned this. . so i will ..

maybe the 3000gt SL was a auto?

neyways.. good kill. and i enjoyed reading about octane.. 91 octane top here in CA.. it does good for my valves. Techron Baby!

[NutBucket]

Yet another money waster.

[owequitit]

hmmm.. no body mentioned this. . so i will ..

maybe the 3000gt SL was a auto?

Actually, I mentioned it in one of my first posts, but that is ok.

[TheNextAZN]

What if it was an auto? Did anybody bother to consider that?

I have seen some special conditions (extremely high heat ETC) where they run a little better on 91 octane, but anything above that is a waste.

damn!! i must of been flooded with all this octane talk .. the fumes may have gotten to me and i forgot.

and as for the special conditions .. i didn't know that about high heats and 91 octane!! .. lol damn.. i was running 91 octane back when i lived in the valley(and gas was $1.50 and "too expensive") ..in 105-110 degree weather. sweeeeeet! octane tuning FTW!

[wlfpck]

LOL!

You may know what octane is, but you clearly don't know what it does...

It has nothing to do with the amount of energy contained in the fuel. A gallon of gas has a pretty constant amount of BTU's in it and it remains relatively constant from grade to grade, although high octane fuels actually have slightly less total energy potential.

Octane is a flame INHIBITOR. That means that with more octane, the flame front travels SLOWER under the same conditions as it would if the octane were lower.

Octane is good in situations where we need the flame to travel slower, such as under high thermal loads provided by either 1)High compression 2) High boost or 3) in some extreme cases, high temperatures.

With lower octane in these circumstances, the pressures and temperatures are such that fuel with a lower octane rating will not expand rapidly and in a controlled fashion as it typically does. Instead it detonates or explodes, causing a severe spike in cylinder pressures, potentially causing severe damage and leading to the charachteristic "pinging" noise.

Unless a car is specifically tuned to take advantage of the slower flame propogation or is going to ping without it, then additional octane isn't going to do anything for you.

In fact, it has been dyno proven to lose power slightly.

Why?

In the time it takes the flame to expand, the piston is further past TDC, resulting in a larger cylinder volume by the time the flame front gets to the piston. Since the force driving the piston down the bore is inversely proportional to volume (less volume equals more force on the piston), you get LESS force on the piston, and thus less HP at the crank, wheels or where ever you care to measure it. The slower flame movement is offset somewhat in a really dense air/fuel mixture such as high compression or high boost.

Octane is beneficial to an engine right up to the point that it no longer detonates under the conditions that it was tuned for. Once detonation no longer occurs, adding more octane is useless, unless the car is retuned to take advantage of it.

Since your F22A1 was designed and tuned to run on 87 octane, putting 105 octane race fuel in your car does nothing for anything, unless you have significantly altered the car, which is what I asked you earlier, and you ignored.

If the car had a knock sensor to adjust timing based on fuel quality, then I could understand your statement, but the F22A1 doesn't have one, and thus has no way to adjust for higher octane. So unless you have changed something big, your butt dyno is lying to you.

And actually, it is also a proven fact that engines make peak power with just a twinge of pinging under high loads.

Nobody is flaming from their "stupid half", but the science does not add up in favor of your story.

You are more than welcome to prove us wrong, but based on knowledge and experience, that isn't going to happen, unless you are changing something mechanically that you aren't talking about.

Sorry dude.

damn.... sounds like someone has a degree in mechanical engineering. can you tutor me? no i'm serious.

[TheNextAZN]

damn.... sounds like someone has a degree in mechanical engineering. can you tutor me? no i'm serious.

lol .. not mechanical engineering .. lol. u must mean, Mechanic Specialist. I say .. a physis/chemist/mechanic

[mullet]

Seems to be a typical case of butt dyno inconsistancy. Higher octane should in his mind mean more power, therefore he FEELS more power.

I don't doubt the kill simply becasue the SL's a re complete pigs, and it's possible it was an auto. I will however say it had nothing to do with running 105 that night.

Until a dyno is used with various octane fuels in similar conditions, there is absolutely no way you can say you gained power. Feeling more power is nothing like seeing more power

[owequitit]

lol .. not mechanical engineering .. lol. u must mean, Mechanic Specialist. I say .. a physis/chemist/mechanic

LOL! None of the above really. Just an enthusiast.

[owequitit]

damn.... sounds like someone has a degree in mechanical engineering. can you tutor me? no i'm serious.

Well if you have questions, let me know and I will help the best I can.