What can I add to gas to boost my octane rating for safety margin?

[JeremyD]

Really - unless you are Michael Schumacher undercover, or have extensive track experience, I sincerely doubt you'll be at 9/10's on the track as a green student [if it's PCA]

Usually you'll want to start out at controlled speed, smoothness if you are at 7/10's on your third session of the day you'll be doing better than 95% of typical first time students.

You can still have gobs of fun shifting before 6,000 rpms. You'll also discover that the car is capable of so much more than you thought. have fun!

[RWebb]

a green student might be at 9/10ths very briefly... just before the dust cloud.

[HarryD]

Originally Posted by Steve@Rennsport

The use of E10 or E85 will certainly require a mixture change as an engine calibrated for gasoline runs leaner with varying combinations of Ethanol.

Your LM-2 will show the differences,...

Steve,

As you know, I have posted on this before. My thoughts in this thread (Effects of Ethanol in gas) are:

Originally Posted by HarryD

Hate to burst your bubble but E85 requires a significant change in the air fuel ratio to be at stiochiometric (exact amount of fuel to use all the air). E10 is close enough to straight gasoline that these changes are not needed. FWIW, at Stoichiometric you get max power at lowest emissions.

For gasoline, the optimum air:fuel ratio is 14.7:1, for E10 the stoichiometric air:fuel ratio is 14:1, and for E85 the stoichiometric ratio is 9.8:1.

Unless you do some serious tweaking to your CIS Control pressures and springs in you other control devices, I doubt you will be able to get the car to run poorly if at all.

E85 is an adequate fuel but the car needs to be specifically designed for it. This includes the materials that touch the fuel and the controls that meter the fuel.

Interesting reading: http://www.allsafe-fuel.org/TechPaper.pdf

[Steve@Rennsport]

Good show, Harry.

JMHO, but Ethanol is for drinking and gasoline is for motor fuel.

[Steve W]

It's important to understand that when analyzing AFRs with different fuels and combinations, that you cannot use AFR ratios anymore in the traditional sense to determine if an engine is running lean or rich. You'd want to go by the Lambda values which is actually how the factory engineers look at it.

The Lambda value is the ratio that the fuel mixture is at or deviates from the Stoichiometric ratio, the ratio for the chemically correct air/fuel ratio necessary to achieve complete combustion of the fuel. Under complete combustion, without excess oxygen after combustion (lean) or a shortage (rich), Lambda equals 1.0. For pure gasoline the stoichiometric ratio is 14.7:1, or 14.7 parts of air for each part of gasoline. However for different fuels, the air/fuel ratio is different for each to achieve Lambda 1.0.

For common fuels this is:

Methanol, 6.4:1
Ethanol, 9.0:1
MTBE, 11.7:1

As you can see, for methanol, it would require more than twice the amount of fuel for the same amount of air to equal the energy output of pure gasoline, thus the decreased fuel efficiency and potential leaning mixtures from switching to such fuels or similar oxygenated gasolines. If you're seeing an AFR of 15 or 16:1 with an alcohol fuel, that's like seeing an AFR of 25 or 30:1 on gasoline!! In other words, you can not use the target AFRs for gasoline with alcohols.

Using your LM-1 or LM-2, you must either know the correct target AFR for your fuel, or switch over and focus on Lambda instead, which is a target reading that always remains consistent, irrespective of the fuel or combination used. For example on a LM1 or LM2, if you were running pure ethanol, if you read a Lambda of 1.0, you will simultaneously see an AFR of 9.0, where you'd want to be to normally be at idle and cruise, and where the O2 sensor would try to modulate it to if the fuel system had the range to deliver the increased volume. If you're running an alcohol fuel or mix and expect to see a stoichiometric at 14.7:1, forget about it as that would be incorrect and look at the Lambda which you want to be 1.0. If expecting to see 13.0:1 under power, instead focus on your Lambda at 0.88-0.89.

[shnewberry]

I saw a well written article about octane boosting with Toluene. I think it fits right in with this thread.
Toluene - Octane Booster FAQ

[Dixie]

Originally Posted by JeremyD

Really - unless you are Michael Schumacher undercover, or have extensive track experience, I sincerely doubt you'll be at 9/10's on the track as a green student

Originally Posted by RWebb

a green student might be at 9/10ths very briefly... just before the dust cloud.

The student thinks there at 9/10th when the off-road adventure occurs. They're really only running about 7/10ths. Thats why the car, driver, and instructor usually come out unscathed.

[efhughes3]

I'm just amazed that someone would ask how to raise their octane level, and not post what the heck they were using for fuel when they posted.

[SpeedracerIndy]

Originally Posted by efhughes3

I'm just amazed that someone would ask how to raise their octane level, and not post what the heck they were using for fuel when they posted.

No need to be amazed. In fact, I got quite a few helpful responses and learned a lot about fuel when I posted this close to 3 months ago.

Thanks to at least three helpful people here on Pelican, I have located a few sources of race fuel here locally. I'll be mixing the race fuel with the mystery gas that I use regularly for my first track event. I'll feel much more comfortable knowing that when I'm driving 1/10th, 5/10ths, 7/10ths or whatever level I am able to achieve, that I don't have to worry about my motor suffering from detonation.

[bossladys 911]

The Speedrome race track on the eastside of Indy has 110 octane nearby . Also The Sunoco on US 40 at the NW corner of the Indy airport property has 110 .Also the Sunoco near Oreilly Raceway main gate has it . Enjoy your track time and keep the shiny side UP .

Eddie