Race fuel, 100 or 110 Octane?

[HURTNEM]

For the guys that run race fuel does it make a difference in your car's performance when you use 110 versus 100 Octane? I see some people use 100, 107 and 110, so I'd like to know from people who've used 100 and above to see if 100 is all you need or if there was a true benefit from the 107-110. Thanks.

 

[Fat-cat]

if you run to much octane for the amount of air your car moves / Comp ration then there is a detrimental effect to performance.

You would not want to run 110 on a 16 pound T/S car 100 would be fine. But on a 23 pound T/s Car with 107/110 would benefit form the higher octane and Timing. You and only run so much timing in a car. Its best to talk to your tuner and they can recommend what they found works for a given application.

I guess in short. Depends on boost and mods. Big boost / Timing needs more octane. Lower boost big timing does not need as much. A eaton n20 car will need less octane then a Whipple N20 car.

 

[03 Whippled Cobra]

For the guys that run race fuel does it make a difference in your car's performance when you use 110 versus 100 Octane? I see some people use 100, 107 and 110, so I'd like to know from people who've used 100 and above to see if 100 is all you need or if there was a true benefit from the 107-110. Thanks.

Rodney,

The benefits of Octane come from the increase in boost and timing you can run. You do not get any added benefit just by putting in higher octane. However, using higher octane allows you to up the boost and timing a little and get more power. As stated above, it is up to your tuner how much extra boost and timing they feel comfrotable with at certain octane levels.

Lets say you run a ported Eaton, upper and lower pulley, making 17#'s boost. Your tuner may safely tune your car for 93 octane by keeping max timing at 23*. However, if you were to run 100 octane they could dial in more timing and safely keep max timing at 25*. If you up the octane again up to 116 they may feel comfrotable adding another 2* timing up to 27*. These are just examples, but you get the point. The benefit from octane comes from added timing and or boost. So yes there is a difference between the octanes you run and the timing your tuner feels comfortable with.

Mike

 

[HURTNEM]

Makes sense now! Thank you both for the replies. I didn't know why some guys were running 100 while others were running 110 etc and the cars had the same mods pretty much. Now I see they may have different tunes set for different boost/timing even though both cars may have the same mods. Thanks again.

 

[03 Whippled Cobra]

Makes sense now! Thank you both for the replies. I didn't know why some guys were running 100 while others were running 110 etc and the cars had the same mods pretty much. Now I see they may have different tunes set for different boost/timing even though both cars may have the same mods. Thanks again.

Yep, it is all in the tune. More boost and timing will need more octane to prevent detonation, that is all it comes down to...

 

[ditchsnake]

boost octane timing

so does anyone have a chart on timing, boost and octane requirements

 

[03 Whippled Cobra]

so does anyone have a chart on timing, boost and octane requirements

That would be too hard to put together becasue compression ratio also comes into play.

I can say that with our Terminator motors and a compression ratio of 8.5:1, with 93 octane I would never run more that 19# boost and 19* timing. But that is just me. I would also add that every pound of boost that you take away I would add 2* timing. So I would do 19# and 19*, but I would also run 17# and 21*. There is always that give and take when it comes to the amount of boost and the amount of timing. Again, that is only with out 8.5:1 motors. As soon as that CR changes then these numbers change along with it. As for race gas well that is up in the air. On the Terminator with some C16 I would be OK running maybe 23-25# boost and 20-21* timing. But they also change with the exact octane I would be using. This is when having a knowledgable tuner comes in handy.

 

[divided]

Some good info in here. I had no idea either.

 

[03 Whippled Cobra]

Forgot to mention that A/F ratio will also play a key role with the amount of boost and timing you could/should run.

 

[FlaSeaDude]

One other thing to consider. In the area where I live, 100 octane is available from Sunoco and it is unleaded while the 110 octane that is available from Gate is leaded. If you're still running cats, this could be a concern...:beer:

 

[unforgiven]

Some great info here, thanks. My 2.3 Whipple has 18psi w/18* timing on 93 octane (11.6 AF). I was hoping that was safe.

 

[PWORLDSTANG]

That would be too hard to put together becasue compression ratio also comes into play.

I can say that with our Terminator motors and a compression ratio of 8.5:1, with 93 octane I would never run more that 19# boost and 19* timing. But that is just me. I would also add that every pound of boost that you take away I would add 2* timing. So I would do 19# and 19*, but I would also run 17# and 21*. There is always that give and take when it comes to the amount of boost and the amount of timing. Again, that is only with out 8.5:1 motors. As soon as that CR changes then these numbers change along with it. As for race gas well that is up in the air. On the Terminator with some C16 I would be OK running maybe 23-25# boost and 20-21* timing. But they also change with the exact octane I would be using. This is when having a knowledgable tuner comes in handy.

so does anyone have a chart on timing, boost and octane requirements

Assuming stock 8.5:1 compression ratio, I would not recommend this much boost and timing on pump gas. That would get this guy more "wasted pistons".

On 93 octane and 19lbs of boost, most timing I'd run is 17 degrees. Also, for every pound of boost you take away, it is safe to add just 1 degree of timing.

Again, this is assuming stock compression on his 93 octane pump gas.

EDIT: Typo, changed to 93 octane.

 

[PWORLDSTANG]

so does anyone have a chart on timing, boost and octane requirements

Here is some info that will help you:

[ame=http://www.modularfords.com/forums/showpost.php?p=1359247&postcount=5]ModularFords.com - View Single Post - Timing help 91 Octane and Whipple 15 psi[/ame]

[ame=http://www.modularfords.com/forums/showpost.php?p=994592&postcount=7]ModularFords.com - View Single Post - Acceptable timing...[/ame]

 

[03 Whippled Cobra]

Assuming stock 8.5:1 compression ratio, I would not recommend this much boost and timing on pump gas. That would get this guy more "wasted pistons".

Well this is a complete opinion by you. You cannot just make a blanket statement that somone running 19# and 19* is going to "waste" pistons? :shrug:...I ran that for a long time with my Whipple, along wih tons of others on this site and it is perfectly fine. I will say, again, that 19# and 19* is the tops of my safety level on 93 octane.

[/quote]On 93 octane and 19lbs of boost, most timing I'd run is 17 degrees. Also, for every pound of boost you take away, it is safe to add just 1 degree of timing.[/quote]

Again your opinion and it totally makes sense. All owners and tuners have a safety level for a specific octane. 19# and 19* isn't that much different than 19# and 17*, but it is what it is. Good point.

[/quote]Again, this is assuming stock compression on his 91 octane pump gas.[/quote]

Where did 91 octane come from? All of my "opinions" and experiences were based on 93 octane. If we are talking 91 octane then my numbers change, of course.

 

[PWORLDSTANG]

Where did 91 octane come from? All of my "opinions" and experiences were based on 93 octane. If we are talking 91 octane then my numbers change, of course.

Yes, I caught that. I edited my post before you replied. 91 is the highest I have in CA, so that's just what I'm used to typing.

However, all of my figures in the post you quoted were specifically referencing 93 octane, and none of which were changed with my edit.

 

[03 Whippled Cobra]

Yes, I caught that. I edited my post before you replied. 91 is the highest I have in CA, so that's just what I'm used to typing.

However, all of my figures in the post you quoted were specifically referencing 93 octane, and none of which were changed with my edit.

That's cool. I'm not here to argue. All tuners have their comfort zones and I think when it comes down to it most of those ranges are fairly close to one another. I'd say the boost levels and timing levels are all within 2# and 2* of one another for safety purposes. Others like to push the limits but not me. Not worth it...:beer:

 

[PWORLDSTANG]

Well this is a complete opinion by you. You cannot just make a blanket statement that somone running 19# and 19* is going to "waste" pistons? :shrug:...I ran that for a long time with my Whipple, along wih tons of others on this site and it is perfectly fine. I will say, again, that 19# and 19* is the tops of my safety level on 93 octane.

On 93 octane and 19lbs of boost, most timing I'd run is 17 degrees. Also, for every pound of boost you take away, it is safe to add just 1 degree of timing.[/quote]

Again your opinion and it totally makes sense. All owners and tuners have a safety level for a specific octane. 19# and 19* isn't that much different than 19# and 17*, but it is what it is. Good point.

[/quote]Again, this is assuming stock compression on his 91 octane pump gas.[/quote]

Where did 91 octane come from? All of my "opinions" and experiences were based on 93 octane. If we are talking 91 octane then my numbers change, of course.[/QUOTE]

Looks like both of us are making typos and fixing them at the same time. Lol.

Yes, those figures are my opinion. However, my opinion is on par with what most tuners would agree on as being 'safe'.

What is ironic is that you're completely right - many people do run the amount of boost and timing you posted and have no issues with it. I have seen it posted on here on more than one occasion.

The figures I posted not only follow the guidelines to the links that I posted (from RWTD), but my tuner, as well as other reputable tuners. The only thing that it doesn't leave is a safety margin to help protect against detonation.

I'm curious, did Jon Lund tune your car or have you since sourced another tuner?

I ask because Lund has a great reputation, and is considered one of the best in the country from what I have read. If he tuned your car with 19lbs and 19 degrees of timing, it must be of his professional experience that that is a safe boost/timing level on your 93 octane pump gas (though I'd never personally run it).


Edit: Not arguing either, just sharing knowledge. Disagreements are fine, and to each his own, which is why these figures vary from tuner to tuner.

:beer:

 

[03 Whippled Cobra]

I was just going to write, this is not the opinions of Jon Lund! hahaha...I'm just going off of what I have heard from different tuners and different owners experiences over the course of owning ported Eatons, Whipples, and Turbos. RWTD is totally respected on here and I won't argue with their numbers that you posted. But, as stated above, these are all subject to each tuner and each owner, but the good thing is that all of the numbers for a safe tune on 93 octane are really close to eachg other.

 

[PWORLDSTANG]

I was just going to write, this is not the opinions of Jon Lund! hahaha...I'm just going off of what I have heard from different tuners and different owners experiences over the course of owning ported Eatons, Whipples, and Turbos. RWTD is totally respected on here and I won't argue with their numbers that you posted. But, as stated above, these are all subject to each tuner and each owner, but the good thing is that all of the numbers for a safe tune on 93 octane are really close to eachg other.

Ok, I was just wondering of those figures were from what you're running in your Jon Lund tune. If so, that would have been the first time I've seen figures so high from such a respected tuner. But being that it's not something posted from Jon Lund himself, you can't take it for much.

And FWIW, I am no tuner either (yet at least). I am however currently learning and have SCT's tuning tutorial and Greg Banish's Engine Management book I've started reading before I pick up SCT's PRP software. So the figures I posted should not be taken as "just", but they are from what I have learned.


:beer:

 

[FLYIN]

Question, I have is in regards to guys running lead and C16. Running lead is bad for cats I know that and I haven't been concerned about that since I haven't run cats forever, but what about the O2 sensors. Do the guys who run lead just replace the O2s all the time? My car has been on 100 unleaded only for well over the last 3 years. Ended up running some leaded gas once to get me through because I didn't have 100 unleaded readily available. Killed my wideband and O2's real quick. I knew it could damage them, but I didn't know it happened that quickly. So, what do the C16 only guys and the ones that require that much octane where unleaded is not an option anymore do? Highest unleaded I have ever seen is the VP MS109 which is 105 unleaded not 109 like I have heard many incorrectly say.