Octane booster

[knobbytracks]

I was curious to see who is using octane booster, what brands seem to work best, and if it's even worth it. Also, is there any difference from those for autos compared to motorcycles? Thanks in advance for the replies.

 

[Tantrum]

Just curious. Why would you use octane booster when there is 108 racing gas out there? Do you not have access to it? It's about $4-5 a gallon and a bottle of the octane booster is roughly the same. Your not going to be able to mix the ratio as advertised on the bottle since it is designed for use in cars, which would never need 108 octane anyways. You would probably need to add the whole bottle in order to get to the desired octane. By that time you have so much additives in your gas that it could possible run like crap. I dont know, Ive never done it. IMO those octane boosters are a load of crap anyways. Its like that bottle of "Stop Smoke" that you can put in your oil to prolong the life of a car that has 200,000 miles on it. ;)

B.

 

[penguin]

#1 rule...The stock KDX runs fine on super unleaded

#2 rule...if it comes in a plastic can, it is worthless.

#3 rule...Most octane boosters contain toulene or other nasty, toxic chemicals and are not good for crank seals or air boots

 

[canyncarvr]

I'm sure I haven't tried them all, but Clifford Research's 104+ is the ONLY 'crap in a plastic bottle' that is any good (read: does anything).

But...why?

Increased octane is not always a good thing. In a motor that is designed to run on 92 octane gas, what's the point? A higher octane fuel is mainly going to burn slower than a lower octane fuel. This may be advantageous in a 2-stroke with higher compression due to modification, but in a stock bike?

BTW..my kdx WITH octane booster in it ran the same against a twin (samely modified) kdx. I THOUGHT it ran different, but the result (measuring it against an otherwise unchanged bike) was the same.

It makes your spark plug a pretty color. Is that important?? :think

re: bottles of 'stop smoke'....

Would THAT work in a 2-stroke?:) Or....for 2-strokes would it be called, 'Stop Spooge'???

 

[WR 250]

I've been running into this issue with my new 440 snowmachine. It requires 91 octane and the highest octane gas they sell in my little town is 90. I did some cost comparisons between avgas and 104 octane boost at $12 something a bottle and found that it is cheaper to mix avgas with regular 87 unleaded.

I found it interesting that the Carquest brand of octane boost did not list what octane rating it achieved when you mixed it in. My guess is that it does not do anything.

 

[canucklehead]

You might wanna research that avgas decision. As far as I know, avgas contains LEAD additives (which boost octane) and could cause some issues for your 2-stroke. Not sure, but I'd check with Rich or one of the other guys in the Technology forum.

If your sled says it needs 91 octane, and you run 90, I seriously doubt you'd notice ANY difference at all. Personally, I wouldn't think twice about running 90 octane as it should be fine.

Dave

 

[spanky250]

Here are a couple of threads with some good info on octane boosters, and an excellent description of various octane boosters by Rich:

http://dirtrider.net/forums3/showthread.php?s=&threadid=5225&highlight=octane+booster

http://dirtrider.net/forums3/showthread.php?s=&threadid=5224&highlight=octane+booster

Most of the 104 line of products have varying levels of MMT in them. While MMT is a pretty good octane booster BUT it leaves combustion chamber deposits VERY quickly. These deposits lead to pre-ignition and knock in two-strokes pretty quickly so guys add MORE octane booster which leads to more deposits, more knock ... you can see where this is going.

I've never liked octane boosters as a substitute for race gas, but given the number of people who send e-mails asking about them it's apparent that people want to know more. They will never replace the real thing, but octane boosters can be useful at preventing knock if you only need to raise the octane a few points, but they come with a host of caveats.

The pros:
- Conveniently located at your local dealer or auto parts store
- Easy to transport
- They are cost effective if your octane needs are minimal

The cons:
- Most boosters raise the RON octane more than the MON octane, which
makes them fairly useless for most race applications, or high load
high heat situations
- Most of the better additives at this point are either Toluene or MMT
based. Toluene has the advantage of being relatively cheap, and fairly
effective at raising the octane even in fairly high percentages. Plus
it has good resistance to pre ignition which is an important consideration
in a two stroke. The downside is as you raise the percentage of Toluene
(or most aromatic hydrocarbon based additives) , the throttle response
quickly becomes flat and mushy. The snap goes BYE BYE.
So the engine won't knock, but it probably won't run worth a damn either.
- MMT based boosters (the most common today) quickly reach a point of
diminishing returns (i.e. the more you add the less it helps)
- Organometallic boosters like MMT can cause a huge increase in engine
deposits, and increase the risk of plug fouling and pre ignition
- Most boosters tend to kill the throttle response and make it
difficult to jet. Mix in the constantly changing base fuel your mixing
it in and you have a constantly moving target.
- Most octane boosters (especially toluene based) have high solvent
properties which can raise hell with reeds and crank seals in two-strokes
- If you need to raise the octane a significant amount, octane boosters
are much more expensive and much less effective than race fuels

There's more to it than this but I'm sure you get the point. Basically
it boils down to this, if your engine only needs a small increase in
octane as a safety margin then using octane booster is still better than blowing it up, but you'll likely give up throttle response for the
convenience. If you need a large increase in MON octane you won't get it from octane booster without paying more than you would for real race gas in the first place, plus it will run BAD. No snap, and an impossible to read plug.

During some testing I've done with VP "Octane Power Boost" (MMT based) on my YZ417 (13.25 :1 CR). I've also noticed a reluctance to start when the engine is cold, although this may be application specific. The throttle response isn't as good as running VP-C18 or C-12 but it's doesn't knock, and the power you give up on the top end would only be noticeable to guys running flat out all the time.
Even though I hate to recommend octane boosters, if you have to use them here's some things you can try in order of my preference based on my testing on a 92mm stock compression (12.5:1) YZ400, and a 94 mm (13.25:1) compression YZ417. I used Amoco Premium as my base fuel in all tests, which were done in fairly warm 80-95 degree weather. My results probably aren't really useful to anyone who isn't running a similar combination, but they hopefully will shed a little light on the subject.

VP - "Octane Power Boost" - MMT based mixed 1 OZ./gal.
Pretty good throttle response once you get the jetting sorted out which tended to lean out on this combination. This was probably the closest to good race gas that I've seen. Raising the percentage of VP quickly killed the throttle response and made it much more difficult to start cold. This would be a reasonable choice if you can't get race gas or just feel cheap. Street price $10 for a 16oz bottle.

Snap "The Outlaw Racing Formula" - MMT based mixed .75 OZ./gal. Reasonable throttle response not quite as sharp as the VP additive but close. Jetting tended to lean out on this combination. Raising the percentage killed the throttle response and made it much more difficult to start cold. This is easy to find at most auto parts stores and speed shops. Street price $10 for a 16oz bottle.

On tear down of the engine the MMT boosters which seemed reasonably good, dropped way down in my estimation once I saw the incredible deposits left behind by the MMT. I knew MMT was prone to heavy deposits because the plugs are impossible to read due to the rust colored deposits, but I wasn't expecting to find the high level of deposits on the head and piston crown. These depoits will quickly heat up and cause hot spots in the chamber. Bad juju all around.

PJ1 - "Gas Energizer Octane Plus" Toluene based mixed 2 OZ./ gal.
Throttle response is fairly soft when mixed at 1 OZ./gal and gets worse as you increase the percentage, jetting tended to less sensitve to this additive. Top end pull was a better than the MMT based additives at 2 OZ./gal. I've heard that this product has been discontinued, but no confirmation at this point. Street price $6 for an 18oz bottle.

Maxima - "Hi-test Octane Booster" mixed 2 OZ./ gal.
This appears to be a Toluene based additive, but Maxima doesn't list the specifics in their literature. Like the PJ1 additive throttle response is fairly soft when mixed at 1 OZ./gal and gets worse as you increase the percentage, jetting tended to be less sensitve to this additive. Top end pull was a better than the MMT based additives at 2 OZ./gal. Street price $4.50 for a 16oz bottle

 

[WR 250]

Thanks for the links Spanky.

Canucklehead,
I did some more checking with my dealer and he in turn called the Ski-doo factory and talked to the race dept. He found that I can run as low as 87 octane as long as I jet it two steps richer or just one size richer for 90. I'm glad because 100 low lead avgas cost $2.71 per gallon and is a hassle to purchase. Before I picked up my machine I had low compression heads put in just so I wouldn't have to deal with buying race gas or other pain in the butt fuel issues. I think we finally have it figured out now. :)

 

[ihillig]

im sure that its bad for the bike, but i heard about using moth balls for "octane boost". i think it is 99.9% nepthalene or something.
just a thought

 

[Rich Rohrich]

Originally posted by ihillig
im sure that its bad for the bike, but i heard about using moth balls for "octane boost". i think it is 99.9% nepthalene or something.
just a thought

This one has been around since before I was born. :)

Like so many things, there is a SHRED of truth in here, but the "BS effect" has blown this totally out of proportion over the years.

REAL mothballs are made from Napthalene and some binders and has no oxygen molecule. Napthalene is used as a reference fuel in diesel fuel testing. Diesel Cetane ratings are the inverse of Octane ratings, the higher the cetane number the greater the tendency to knock. Napthalene in reference (reagent)form has a cetane rating rating = 0. Depending on who you ask this translates ROUGHLY to an MON octane rating about 90. Pump fuel in the US currently has an MON rating a couple of points lower than 90.
So there is the THREAD of truth I was reffering to.

What the mothball proponents fail to realize is Napthalene has a boiling point of ~420 degrees F. That's anywhere from 100-200 degrees F higher than most gasoline components. If a component of gasoline fails to make the all important liquid to vapor transition then all it will do is pass through the combustion chamber leaching heat along the way. In simple terms it goes from the tank and back out the exhaust UNSCATHED. Even if you could vaporize the Napthalene and burn it, the energy available and the heat of combustion is too low to be of any use.

Naptha is just an early process component of gasoline. There are a lot of steps to go from Naptha to gasoline, so it's subject to essentially the same caveats as Napthalene.

Anyone who has been around manufacturing for more than a few days knows that when it comes to commodity products like these, purity takes a back seat compared to "cost to manufacture". In a word these compounds are full of random junk.

So experiment away, but in the end it's just an excercise in chemical futlity.

 

[ihillig]

too complicated for a 15 year old to understand, im not racing so ill just skip it-
thanks
Illig

 

[penguin]

which was the point of most of our posts....wise decision....roost on!