Regular vs. Premium

[wmccrxpower]

DUDE! Why didnt you give us a holler? Sure could have used some of that cheap gas, since everything we own takes that expensive shit!8-O

[WMCC Gary]

DUDE! Why didnt you give us a holler? Sure could have used some of that cheap gas, since everything we own takes that expensive shit!8-O

I figured you already knew. Everyone else in town did!

[81DaytonaPaceCar]

I really did not see much of a difference when I ran Torco at the track. Does it take a bit to be recognized? I genereally run 92/93 octane....

You may not see any difference. Depends on your motor setup and external conditions (i.e. temperature, altitude, etc.).

You're not inventing horsepower with it, you're preventing horsepower loss.

[wasjo6431]

but one hting is true. leaded fuel on amotor not made to run leaded fuel. will in the long run damage the motor will it not?

leaded fuels burn hotter if i do recall

[01WU8]

but one hting is true. leaded fuel on amotor not made to run leaded fuel. will in the long run damage the motor will it not?

leaded fuels burn hotter if i do recall

I heard this also, and that it will clog up cats too...

[MattODoom]

I heard this also, and that it will clog up cats too...

Any self-respecting car enthusiast is quick to solve that problem known as the "catalytic converter".

[01WU8]

Yeah, it is something I have not got around too yet. Everything bone stock!

[SS4Matt]

haha yeah i was about to ask what a cat is? and why you would want one on your car

[wasjo6431]

Ive had a cop ask me why i dont have them. i told him the motors pre converters. he said well you better put some on an dwrote me for just loud exhaust. (shrug) thank god he didnt give me the ticket for no cat's its a huge ass fine

[dsgrntld187]

Ive had a cop ask me why i dont have them. i told him the motors pre converters. he said well you better put some on an dwrote me for just loud exhaust. (shrug) thank god he didnt give me the ticket for no cat's its a huge ass fine

I don't think I've had any cars recently that have had a cat..

Screw that.

[Deleted]

Thanks for all your opinions guys.

[02hawk796]

I don't understand why some people are saying there are no horsepower gains from higher octane fuel - and nobody is calling on that claim.

Higher octane fuel has a slower burn, and with internal combustion that means a longer burn.
lower octane fuel has a more brief detonation, and then it's done with the burn.
From a leverage point of view, the best leverage a piston/rod has against the crank is at 90 degrees, or around the halfway mark of the piston's "down" or "power" stroke. Of course, the combustion chamber is larger at this point, too.
The longer burn allows the detonation not only at (or just after) the peak position of the piston (smallest chamber), but the sustained burn as the piston travels in the power stroke, getting closer to the better leverage postion of the piston/rod against the crank.
Since energy in the universe is not "created", I suppose technically we are not "inventing" horsepower. But if the applied horsepower is not resulting in the engine producing more output hp from the higher octane, then something is wrong.
None of this applies to rotary engines, of course.

[81DaytonaPaceCar]

Found an excellent article on the net:

http://www.faqs.org/faqs/autos/gasol...section-1.html

It's somewhat lengthy, and covers a pleathora of things besides octane (including ignition), but here is the short story :

NOTE #1: The octane numbers listed below are for engines without an engine management system

NOTE #2: Interesting that the author states that engine thermal efficiency maxs out at 17:1 compression
__________________________________

7.2 What is the effect of Compression ratio?

Most people know that an increase in Compression Ratio will require an
increase in fuel octane for the same engine design. Increasing the
compression ratio increases the theoretical thermodynamic efficiency of an engine according to the standard equation

Efficiency = 1 - (1/compression ratio)^gamma-1

where gamma = ratio of specific heats at constant pressure and constant volume of the working fluid ( for most purposes air is the working fluid, and is treated as an ideal gas ). There are indications that thermal efficiency reaches a maximum at a compression ratio of about 17:1 for gasoline fuels in an SI engine [23].

The efficiency gains are best when the engine is at incipient knock, that's why knock sensors ( actually vibration sensors ) are used. Low compression ratio engines are less efficient because they can not deliver as much of the ideal combustion power to the flywheel. For a typical carburetted engine, without engine management [27,38]:-

Compression Octane Number Brake Thermal Efficiency Ratio Requirement ( Full Throttle )
5:1 -----72 ------
6:1 -----81 -----25 %
7:1 -----87 -----28 %
8:1 -----92 -----30 %
9:1 -----96 -----32 %
10:1 ----100 ----33 %
11:1 ----104 ----34 %
12:1 ----108 ----35 %

Modern engines have improved significantly on this, and the changing fuel specifications and engine design should see more improvements, but significant gains may have to await improved engine materials and fuels.

[WMCC Gary]

I heard this also, and that it will clog up cats too...

The lead also plays hell on the o2 sensors.

[01WU8]

Yeah, I heard that also. I thought about getting a new ECM programmed the way I want it, that will delete the rear o2 sensors, amongst other things. There is alot you can get programmed and deleted, and this is just one of them.