Race gas

[talontsi01]

I ran a 14.4 @ the track a couple weeks ago on 92 octane.


How much faster would you guys guess if I ran race gas (110 octane) instead?

 

[GSX90]

Hard to really say. This depends on a few factors like boost, airflow, knock, tuning, etc. Assuming your engine/clutch is in good mechanical condition, race gas should allow you to get more timing/less knock at higher boost levels than stock. This should result in more power, better times, and higher trap speeds.

 

[JohnTSI]

Unless you where knocking, just adding race gas will not make you run any faster.

 

[talontsi01]

Is it also true that you can run too high of octane for our engines compression levels?

I heard that running 110 octane in our cars is not a good idea and shouldnt be done.
Can anyone back this?

 

[JohnTSI]

You want to run the minimum octane required for your boost level to make the most power. AT 30PSI I never run anything but 110 in the car.

 

[talontsi01]

You want to run the minimum octane required for your boost level to make the most power. AT 30PSI I never run anything but 110 in the car.

Most people arent running that high. I have 2g pistons (8.5:1) and run 18 psi at the track. What would you recommend?

 

[1993eclipseGS]

Mix some xylene in with your gas

 

[diambo4life]

I ran a 14.4 @ the track a couple weeks ago on 92 octane.


How much faster would you guys guess if I ran race gas (110 octane) instead?

If you were not knocking and just added race gas without doing anything else, you will actually run slower.

Is it also true that you can run too high of octane for our engines compression levels?

I heard that running 110 octane in our cars is not a good idea and shouldnt be done.
Can anyone back this?

People run C116 and 117 gas all the time on DSMs.

 

[BrnOutKing]

basically running Higher Oct Gas - just allows you to run your car leaner, so you make more power, with out harming the motor.

the reason you shouldn't run Higher Oct/Race Gas - is because most of the time it's "Leaded" Gas and ruins your 02 sensor, if you have an External Waste Gate it can wear that down faster.


But if you use it every once and a while it shouldn't be an issue.

Anyways if you have a SAFC or something to control fuel - then go for it. Otherwise your best bet is to just stick with regular pump gas.

 

[hostile]

If you were not knocking and just added race gas without doing anything else, you will actually run slower.



People run C116 and 117 gas all the time on DSMs.

When you add c16 in our cars it actually leans it out a little bit. So not changing anything but putting in gas. You would run a little leaner, which is usually a good thing in our cars.

And you wouldnt knock.

On a turbo car there is no reason why racegas wouldnt make you faster.

You really should turn the boost up to take advantage of the race gas though.

 

[yo2001]

Mine runs way rich on C16 without any change on the fuel setting.

I gain usually 5mph in trap, .4-.5 in ET on race gas

 

[diambo4life]

When you add c16 in our cars it actually leans it out a little bit. So not changing anything but putting in gas. You would run a little leaner, which is usually a good thing in our cars.

And you wouldnt knock.

On a turbo car there is no reason why racegas wouldnt make you faster.

You really should turn the boost up to take advantage of the race gas though.

Read my statement again. You will not run leaner by just swapping pump with race gas WITHOUT making any other changes. You DID NOT change the air fuel ratio. You just changed the "burning" characteristic of the fuel ie. make it burn slower.

If that was the case, we wouldn't need AFCs' to lean out the AFR on race gas (to get more power.)

If your car was not knocking at a certain boost on pump and you added race gas without making any other changes, it will not become faster.

 

[JohnTSI]

Race gas without any other changes will not make your car run faster as I stated before. And like Diablo said it will make you run slower if you are not knocking. Race gas is a higher octane wich results in it being harder to ignite. This is also why it is more resistant to detonation. If you had a 7:1 compression NA motor and put 118 in it the car would have troubles just running with the mixture being so hard to ignite. It does not make your car run leaner just by adding race gas.

 

[hostile]

Do you understand what your saying? I have run c16 in my car many times. I only have 7.8:1 compression and it idles smoother than it does on pump gas, do you know why?

Race gas isn't only high octane gas... it is high quality fuel that has everything in the mix to make the most horsepower. Do you honestly think the gas station puts as much car into the fuel they are selling you for 1.80 as VP's 8 dollar fuel?

The DSMlink guys have noticed racegas makes the car run half a point leaner. Your not only dealing with octane. Race gas hasa higher specific gravity and a differrent blend of hydrocarbons.

Either way, like I said. It would be a waste of money to pay for racegas and not up the boost.

 

[JohnTSI]

Do you understand what your saying? I have run c16 in my car many times. I only have 7.8:1 compression and it idles smoother than it does on pump gas, do you know why?

Race gas isn't only high octane gas... it is high quality fuel that has everything in the mix to make the most horsepower. Do you honestly think the gas station puts as much car into the fuel they are selling you for 1.80 as VP's 8 dollar fuel?

.

Yes I am very much aware of what I am saying but you seem to be speaking about something you do not fully understand. SO let me give you some information....


"Posted octane numbers on gasoline pumps are a result of testing fuel performance under laboratory and actual operating conditions. The higher the octane rating on fuel the less volatile (evaporative qualities) and the slower the fuel burns. Higher octane fuel contains more POTENTIAL energy but requires the higher heat generated by higher compression ratio engines to properly condition the fuel to RELEASE that higher potential energy. In the refining process, fewer gallons of higher octane fuels are yielded from a barrel of raw crude."

To realease that energy you up the compression or the boost it is not released just by adding it to the car. Race gas is not horsepower in a bottle. SHall we continue...

"If fuel octane is too low for a given compression ratio, the fuel prematurely and spontaneously ignites too early and the fuel charge EXPLODES rather than BURNS resulting in incomplete combustion. The net effect is a loss in power and possible engine damage. The operator hears an audible "knock" or "ping", referred to as detonation. Detonation may vary from a faint noise on light acceleration to a constant, deep hammering noise while driving at a constant speed. Improper timing adjustments, vacuum leaks, or excessively lean fuel mixtures may also cause detonation"

In this case where you are running too low an octane, race gas will make more power due to stopping the detonation....

"Many vehicle owners believe that higher octane fuels are better for their vehicles since they are labeled "PREMIUM." The logic is that since it is a premium fuel it must be better. In reality, the premium label originates from the higher cost to refine and the resultant higher retail cost. Some refiners label their high octane fuels "SUPER." Some owners think that these fuels will make their vehicles more powerful. Only engines with high compression ratios can deliver all the potential energy from higher octane fuels! Always consult the manufacturer's octane recommendation to determine the proper octane requirements for any given vehicle. Generally, engines with compression ratios of 9.3 : 1 or less will safely operate with unleaded 87 octane fuel. Engines with higher compression ratios usually require higher octane fuels"

WHen you do require the higher octane fuel putting it in there is not what makes the power. It is turning up the boost and raising the cylinder preassure that alllows you to release the potential energy in the fuel. If the car only needs 93 octane to run properly and not detonate then putting in 110 doen't make more power at that level. Raising the boost will change this yes, but not just pouring in race gas. Higher octane fuel does not detonate as easily because it is harder to burn therefor more resistant to knock. To get the power that is potentially in that fuel you need to increase the cylinder preassure(boost or compression) to benifit from it. There are also other things such as burn rate differences and so on we can go into if you like but for now I will stop.

 

[talontsi01]

Thank you very much for all of this info.


What are most of you guys running regarding octane levels, boost and anything else that relates to this subject at the track?

 

[jdks]

I have been using Shell's new V-Power premium. It's available at any Shell station now and has worked just fine for me.

 

[1993eclipseGS]

Jdks : I've seen the poster up at the shell for this 'v-power'. Exactly what octane is it? It is only $2.05 a gallon where I live but I thought it was just 93octane with a diff name?

 

[jdks]

Well the octane depends on what part of the country you're in... Most premiums are between 90-03. The V-Power has more detergents thus keeps your engine cleaner.