Jump to content
Sign in to follow this  

Race gas question

Recommended Posts

Is it ok to mix 110 octane leaded race gas with 92 octane non-leaded pump gas?

Share this post


Link to post
Share on other sites

It's ok to mix, but be aware that you can't just average the two fuels' octane ratings to get a final rating for the mix. When mixing leaded fuel with another leaded fuel or unleaded with another unleaded a simple average can be close.

But unleaded mixed with leaded is not a linear function. It's a non-linear function of certain constituents of each fuel (actually, this is true for all fuel mixes but it's not so pronounced if you stick with either leaded or unleaded). In other words, you'll never really know the octane rating of your mix unless you have it tested by a lab. That's ok though. If you've got a detonation issue with pump fuel in your engine then all you may need is "more" octane rating. The precise octane rating is mostly irrelevent. A fuel either prevents detonation or it doesn't; i.e. pass/fail.

Also, oxygentated pump fuels and the boutique pump fuels found in many regions of the country can really screw with pump/race mixes. In some cases oxy pump fuels can have a negative lead response.

Share this post


Link to post
Share on other sites

You can mix whatever you want, but, why do you want to run race gas??

Unless you have a higher compression than stock, it's a waste of time.

Share this post


Link to post
Share on other sites
You can mix whatever you want, but, why do you want to run race gas??

Unless you have a higher compression than stock, it's a waste of time.

There are alot of race bikes out there that will suffer detonation problems trying to run on pump gas. I run straight race gas myself so there is no question as to what I am running.

Share this post


Link to post
Share on other sites

I have heard of some guys running 93 octane with the correct amount of octane booster.

Why?

I always just run the 93 - is there something I am missing by not running a higher octane?

Share this post


Link to post
Share on other sites
There are alot of race bikes out there that will suffer detonation problems trying to run on pump gas. I run straight race gas myself so there is no question as to what I am running.

WHat bike with stock compression suffers from detonation when running pump gas?? even CA 91 pump runs great in any stock 4 stroke.

Name one bike.

If you go with a high comp piston thats another thing and I mentioned that in my first post.

Share this post


Link to post
Share on other sites

Mixing race gas with pump gas is a little like mixing chocolate ice cream with dog (stuff). The problem is that even at 50/50, the result still seems much more like dog (stuff) than ice cream.

Then, there's a question of why would would want to.

The figure in the manual is quoted as Research Octane Number (RON). That testing method produces higher numbers than the much tougher Motor Octane Number (MON) method. A fuel with an MON of 86/87 would be equivalent to a fuel with an RON of 95.

Gasolines sold in the U.S. are rated by an average of the two. You see this on the gas pump as "R+M/2". By this method, anything over about 91 is a high enough octane number to prevent detonation, and will work fine in your YZF.

Read more if you like:

http://www.thumpertalk.com/forum/showthread.php?p=2827893#post2827893

Share this post


Link to post
Share on other sites
WHat bike with stock compression suffers from detonation when running pump gas?? even CA 91 pump runs great in any stock 4 stroke.

Name one bike.

A number of two stroke motocross bikes. As you stated, 4 strokes are much more forgiving in terms of what you put in the tank.

Share this post


Link to post
Share on other sites

Grayracer513,

Thanks for posting the attachment. Hope it will help to clear up some of the common misconceptions about slow burning, hard to ignite, cold, low powered race gas!:applause:

Share this post


Link to post
Share on other sites
I have heard of some guys running 93 octane with the correct amount of octane booster.

Why?

I always just run the 93 - is there something I am missing by not running a higher octane?

no. but u can buy gas that has a much higher air Count in the gas that stuff will make you go FAST.

I think its called co2 race gas

Share this post


Link to post
Share on other sites

Race gas...? who needs it, I don't use anything but 91 in my smokers. My friends pay twice as much as me for the "Chevron Blue" I think its called.

Share this post


Link to post
Share on other sites
WHat bike with stock compression suffers from detonation when running pump gas?? even CA 91 pump runs great in any stock 4 stroke.

Name one bike.

A number of two stroke motocross bikes. As you stated, 4 strokes are much more forgiving in terms of what you put in the tank.

Any stock 2 stroke will run pump no problem, it's when you bump up the compression that you need race gas (esp 2 strokes) as I mentioned in my first post.

BTW...Is this Pinger talk or Thumpertalk.

Share this post


Link to post
Share on other sites

I don't think you can say that any two stroke in the world will run OK on 91 octane gas. It does not sound like you have spent much time riding or tuning high performance two strokes. Many two strokes have the compression "bumped up" by the factory as they are designed for high performance not driving to work. I can name not just one but scores of people who have found that pump fuel is not up to the task for their bikes.

The original question did not specify wether or not it pertained to two strokes or four strokes.

If you search this website you will find that there is alot of "pinger talk" here.

Cheers

Share this post


Link to post
Share on other sites
I don't think you can say that any two stroke in the world will run OK on 91 octane gas. It does not sound like you have spent much time riding or tuning high performance two strokes. Many two strokes have the compression "bumped up" by the factory as they are designed for high performance not driving to work. I can name not just one but scores of people who have found that pump fuel is not up to the task for their bikes.

The original question did not specify wether or not it pertained to two strokes or four strokes.

If you search this website you will find that there is alot of "pinger talk" here.

Cheers

I may not be good enough to tell if it makes a difference, but my bike runs good on both 91 and 93 pump gas.

That being said, I AM however, good enough to tell when my bike's performance is sufference, and I would know if detonation was occuring.

Share this post


Link to post
Share on other sites

I've been around plenty of 2 strokes and as long as they are still running a stock compression, with the stock deck height, they run fine on pump gas.

As soon as you tweak the engine all bets are off.

Share this post


Link to post
Share on other sites

My 92 CR500 and older KTM 350 really needed the racing fuel or they pinged horribly. The same is true for my 01 YZ with the 285 kit with the milled head. I also have a tricked out RZ 350 that requires it. It actually sounds like metal rattling without it. They even idle different when you put regular premium pump gas in them. Coming from muscle cars with a lot of advance and compression to turbo cars it really does make a different between having a fun time at the stoplight or breaking the ring lands. I used to load up on the fuel for my Syclone when I really wanted to flog it hard and never blew it up, but the dude I got it off of blew it and his Typhoon up the same week after putting a chip in them. I made sure there was enough fuel getting into it, air, and good fuel. You get what you pay for as far as I'm concerned. I started breaking the drive train once I started getting over 15lbs of boost in it. Ahhhh those were fun days.

Craigus

Share this post


Link to post
Share on other sites

Don't compare apple to oranges, or peaches, either. While all the same principals apply, HC two-strokes and muscle cars, or cars with turbochargers, are each an entirely different beast than the four-stroke dirt bike engines of today.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×