I have access to 125 octane fuel at a local gas station. The owner races and offers the fuel to the general public at one of his pumps. I know of a few friends that have used the fuel in their motorcycles and have not had any problems. I am tempted to try it on my SRT-6 but have never tried it on a mostly stock vehicle before. Has anyone tried this before with our cars? How much hp gain would you expect? This will be a great increase in hp if I don't blow up the engine first (lol).


Leadfoot

 

Does the 125 Octane rating use the (R+M)/2 method? or RON or MON?

Here is a link that provides a good tutorial.

http://www.idavette.net/hib/fuel/index.htm

Search the internet for octane blending charts - there are several out there for blending Rocket 100 Octane gas with regular and premium gas.

I would not put 125 Octane in my SRT-6 but I would fill up with 100 Octane.

Maybe the owner will help you find the proper blend.

 

I've never seen 125 no lead fuel. I'm not saying you are wrong, I'm just bummed that I don't have 125 no lead in my area. In my professional opinion as a race engine builder (not a joke, I really am), run it. Your power will depend on how active the knock sensor is in these SRT6 cars. Octane is great for boosted cars, if this were a N/A car the high octane could hurt power.

I typically put more compression in the street engines that I build for my European customers since 100 octane is common place there. Hey weren't these SRT6 engines designed in Europe, than tuned for the U.S. I'll bet they would love some more octane!

 

I ran a tank of 110 through mine, no noticeable difference.

 

Fill your tank up half with the 125 and the other with 92 or 93 what your local station carries. You should see a difference!

 

What do they charge per gallon?

 

Definitely make sure that it is indeed unleaded gas or you'll destroy your O2 sensors (and by the way there are 4 of 'em). Even though these cars are boosted 125 octane needs a ton of compression and ignition power to ignite that stuff. Just heed the mores law here.

I would personally run 100. That is a considerable increase for even the states that offer 93.

 

I would be a little careful with this one. The highest octane rating i have seen for unleaded is 104. The rating of 125 tells me this is leaded fuel. The main advantage to running higher octane fuel like this is to run more timing which means you really have to tune your car on a dyno. You may see a little advantage but without an engine tune it won't be much. Running leaded fuel will eventually take out your o2 sensors and plug your converter. I ran 104 in my stage 3 srt4 when i would switch it into high octane mode with the turbo toys kit and the difference was unreal but like i said the HOM button advanced the spark to handle the extra octane. Personally i wouldn't do it.

 

I'd imagine that the computer has a limit on how far to advance the spark. The car was meant to run premium, not race fuel.

 

125 octane?! Hmmm...I run VP C12 (112 octane) in my 454 big block (not stock) malibu that runs 10's and it's just right. I cannot see why you would think to consider running 125 octane in the SRT6!! I would think it would do more damage than good, but what do I know...

 

I agree with hawk... Don't do it. You will do more harm than good as it's probably leaded fuel that will potentially void your emission systems warranty if used too much. Without something like Stage 3/toys on the SRT4 to advance your spark, the extra cost and octane really won't do you much good. I too have an S 3/toys SRT4.

 

Thanks for the input. I too have built a few street and track cars over the years. It totally slipped my mind with regard to leaded and unleaded fuel. I called the station and he informs me that it is indeed leaded fuel. As for 02 sensors, someday I'll have to show you how to get around the whole 02 sensor issue. Think Coke bottle!!!


Well unless I do the Coke bottle bypass I won't be running leaded fuel anytime soon. A few of you mentioned timing and octane and most were correct. The ECU in our cars is able to correct timing up to 11 deg either side of center. After that you will need to reprogram. I am looking at the renntech upgrade as well as an accelerator modification I was reading about at this site.


Again thanks for the information.

 

it will be the renntech upgrade for me next spring too.