Found a Tetraethyl lead octane booster

[nephron]

It doesn't matter what kind of Chemistry degree you have. Hell, you could get by with a PhD in chem and not know a damn thing about fuel chemistry, which is probably best taught in petroleum engineering (although I even really doubt that--one of my best friends, and one of the smartest guys I've ever met, is a petroleum engineer and doesn't know a whole lot about the finished race fuel product). I've got a degree in Chemistry from a major university, Suma freakin' Cum Laude, and have still learned all of what little I actually know from Rich. I'm not sure of his education, and I don't care.

What's important? ...seeking knowledge humbly, truthfully and with an open mind. Not regurgitating what you've read on a Hot Rod site or mag. I think Bruce said it best when he was talking about the bulls&&t meter pegging and highly educated people. :laugh: I've still the greatest respect for highly placed individuals in society, but they're perhaps the most susceptible to b.s.'ing for obvious reasons.

I just testified against Barry Brenner ("The Kidney"), Harvard professor of years, in a malpractice case....and he didn't win. No big deal, but proves the point quite well. And I'm not proud of it--won't do it again. Ever. It sucked, but just goes to show...

 

[trialsmasta]

Ok since none of you have been forthcoming with brand names which of these chemicals do I not want in my octance booster.

Toluene
Xylene
Methyl-tertiary-butyl-ether (MTBE)
Methanol or Ethanol
Isopropyl Alcohol and Tertiary Butyl Alcohol

Can I just buy straight Xylene etc and add it to my fuel as a booster?

 

[Rich Rohrich]

Originally posted by trialsmasta

Can I just buy straight Xylene etc and add it to my fuel as a booster?

I think it's important to note that there are different types of Xylenes with distinctly different behaviours in an engine. o-Xylene (1,2-dimethylbenzene), m-Xylene (1,3-dimethylbenzene), and p-Xylene (1,4-dimethylbenzene) are commonly available . You can see that the ring structure is completely different on each one, which changes it's behaviour in the combustion chamber as well.
On the surface the Xylenes seem pretty attractive as a fuel additive but they present a number of problems. You need 272 times as much Xylene by weight compared to tera-ethyl lead (TEL) to get an anti-knock effect similar to TEL. As you increase the percentage of aromatic hydrocarbons like Xylene to the levels we're describing you'll see a marked drop off in throttle response in a normally aspirated engine. The same is true in blown applications, it's just less severe. In a normally aspirated (NA) engine poor throttle response , lazy combustion and subsequent need for increases in ignition advance are common side effects with high percentages of aromatics like Xylene. The difficulty in getting Xylene to vaporize is a critical factor with it's use in a NA engine. A blown application has considerably more heat available in the intake tract to help Xylene vaporize completely. Xylene has nice high octane numbers (RON = 118, MON = 115) , but in practice it seems like these numbers are only attainable when you mix Xylene with high alkylate base fuels (like AvGas) or when TEL is present. In air cooled turbo drag race applications I've had great luck with Xylene, but it's been nothing but a disappointment in NA engines that see constantly changing throttle openings.Once you get past about 2-4 oz/gal most of the good high octane aromatic hydrocarbons (Toluene, Aniline, Benzene, Xylene, etc ) become more trouble than they are worth in a dirt bike or road race application.

So the short answer is, if you need a small boost in octane to prevent knock get some decent leaded fuel and mix a small percentage of it with your pump fuel .

 

[trialsmasta]

Ok Rich, so if I understand this correctly an octane booster is going to sacrifice throttle response in turn for anti knock performance, hence I’m better off blending back a race fuel with some pump gas. The whole reason I want to mess with mixing/blending is my 2003 rm 125 is bone stock but I was told by more that one person that it was a high compression motor and that I would need some anti knock protection or risk ruining my motor. I really can’t afford $6.25 a gallon for recreational riding. I’ve been running PJ1 octane booster, but contemplated switching to the Maxima high-test stuff until I read this post. I now seems like the mixing race gas route seems to be the best method. I do have a question for you though, would it be better to mix 87 with race gas rather than 93 because of the higher heat yield out of 87-octane gas? Is there any truth to the higher heat yield, and is it even worthwhile worrying about? Also what’s your take on Howell race fuels assuming that you’ve ever heard of them? Lastly does a 1:1 ratio of 110 octane to 87 octane gas = 98.5 octane blend

 

[cujet]

Trials, when leaded fuel is involved in the mix, there may be a lead response factor to the octane increase, making it less than predictable. Especially if you are mixing leaded fuel with pump gas.
There are OTC octane boosters that work well enough. Any booster that contains MMT will raise the octane at a reasonable cost. MMT has some disadvantages, such as spark plug discoloration and rust colored deposits in the engine and pipe. I do not dislike MMT, it works well enough and does not result in sluggish throttle response.

While Rich is correct about aromatics, I use toluene regularly (in small quantities) with good results. Dyno tests show no loss of power and in certain applications, a slight gain in power. In small amounts, I suspect you will not be able to tell any loss in throttle response.

I like to think that seat of the pants tuning has merit. If you use a product to boost octane and it works for you, why change? Every engine has different needs! I use 100LL in my 1994 Husky 360WXC. It runs so well on that stuff, I refuse to change. Sure I could pay 4 bucks more per gallon for race fuel; at the rate I burn fuel, that could get expensive. Remember, I am using what works for me!

I do remember being told by some very knowledgeable people that 100LL is not a good fuel for dirt bikes. HA! Just try and keep up to my old Husky!

Chris

 

[Rich Rohrich]

Originally posted by trialsmasta
Is there any truth to the higher heat yield,

No

Originally posted by trialsmasta

Also what’s your take on Howell race fuels assuming that you’ve ever heard of them?

Never used it, sorry.

Originally posted by trialsmasta

Lastly does a 1:1 ratio of 110 octane to 87 octane gas = 98.5 octane blend

Pump fuel and race fuel doesn't blend in a linear fashion so I doubt it comes out to 98.5 .

Below are links to a couple of threads that discuss various octane boosters including those you have mentioned. If you read through all the posts I think you'll be able to make a fairly informed choice on your own.

http://dirtrider.net/forums3/showthread.php?s=&threadid=60651&perpage=20&display=&pagenumber=2

http://www.dirtrider.net/forums3/showthread.php?threadid=15450&referrerid=16241

 

[NO HAND]

Originally posted by cujet
...I do remember being told by some very knowledgeable people that 100LL is not a good fuel for dirt bikes. HA! Just try and keep up to my old Husky!...

Well, I've tried it myself and I found it really kills throttle response; just as I was told here. It feels like if all of a sudden you have a rubber-band instead of a throttle cable. Once you are on the pipe it fell allright to me. If there was a way of giving some throttle response to 100LL I would be interrested though.

 

[Rich Rohrich]

Originally posted by NO HAND
If there was a way of giving some throttle response to 100LL I would be interrested though.

High vapor pressure low boiling point compounds like pentane, acetone, MTBE, and a host of other components can be used to improve throttle response. The problems these compounds pose aren't insignificant though. Cost is high on a per liter basis, and handling/storing this stuff is annoying at best , dangerous at worst. Plus you are basically blazing your own trail in terms of jetting and basic tiuning with combinations like this.

Don't get me wrong. It can certainly be done. It's not news that some smaller race fuel producers have used a base of AvGas that they add their own blend of components to. AvGas is a high alkylate fuel so it makes a pretty good base to work from when playing backyard petrochemist. I've done it with good results but it is RARELY cost effective.

The PROPER race fuel is still a pretty good value when you look at the big picture.

 

[flyinzuki]

Originally posted by NO HAND
Well, I've tried it myself and I found it really kills throttle response; just as I was told here. It feels like if all of a sudden you have a rubber-band instead of a throttle cable. Once you are on the pipe it fell allright to me. If there was a way of giving some throttle response to 100LL I would be interrested though.

My bikes have excellent throttle response with avgas, although each one has boosted compression, and has been jetted correctly.
I do get spooge at the end of my silencer when woods riding though.
BTW, isn't MTBE "liquid throttle response"

 

[trialsmasta]

If I understand this correctly a higher octane fuel will have slower throttle response than a lower octane fuel hence if your bike only needs 96 octane don’t run 118 because you will loose throttle response. With that said if my bike only needs 96 wouldn’t I be better off running 93 pump with octane boost to pump it up to 96 octane or there about rather than some off the shelf 105 race fuel? I’m basing this on the octane closer to what you need would be better than excess. Any truth here? Is chronic use of Toulene based boosters detrimental to your motor or does it just mean you have to do more work when you need to clean your power valves?

The mechanics of it all: What on earth causes one fuel to have good throttle response and the other to not? Eg AV fuel v/s Race gas. What’s a “flame front” and where can I get info on distillation curves. Is there like an idiots guide to fuels.

 

[Rich Rohrich]

Originally posted by trialsmasta
If I understand this correctly a higher octane fuel will have slower throttle response than a lower octane fuel

Nope. Octane alone has nothing to do with it. Distillation curve, and vapor pressure will have the greatest influence on response, but the chemistry of the fuel seems to play a role as well.

Originally posted by trialsmasta
I’m basing this on the octane closer to what you need would be better than excess. Any truth here?

Excess octane won't hurt anything (other than your wallet) in an of itself. How you GET the additional octane can present problems from both a performance and maintenance standpoint.

 

[NO HAND]

Originally posted by Rich Rohrich
High vapor pressure low boiling point compounds like pentane, acetone, MTBE, and a host of other components can be used to improve throttle response...

Thanks, I probably read this post like fifteen times. I'm not sure about giving it a try but I have a better idea of the problem I'm looking at. This thread is so full of good info!!

 

[cujet]

Since my bike is a big bore (by comparison to a 125) the Avgas seems to work well. Throttle response is instant, as are 5th gear wheelies with street gearing. Now if I could only get it to come up in 6th at 85MPH I would be happy.

I hinted at this before by saying that all engines respond differently to fuels. I believe 100LL works well in larger, lower revving engines. Many CR500 riders love 100LL. I suspect the 125cc bikes will need a fuel designed for small engines. However it has been 25 years since I rode a 125!

Chris

 

[trialsmasta]

Originally posted by cujet
However it has been 25 years since I rode a 125!

Chris

:eek: damn you're old heheheheh :laugh:

 

[trialsmasta]

Originally posted by Rich Rohrich


Excess octane won't hurt anything (other than your wallet) in an of itself. How you GET the additional octane can present problems from both a performance and maintenance standpoint.

So what you are saying is octane and throttle response are independent from each other. That got me thinking what would make a fuel have better throttle response. Volatility? Ok this a bit counterintuitive, high octane won’t hurt anything, but isn’t it less volatile than low octane gas, hence less snap when I crack the throttle. On boosters what maintenance problem are you taking about?

 

[NO HAND]

Originally posted by Rich Rohrich
http://www.dirtrider.net/forums3/showthread.php?threadid=15450&referrerid=16241

See, earlier in this post, Rich gave us a link that compares the different octane boosters, and the outcome with MMT was better than the others except for the deposits everywhere inside. This would add up so much maintenance to a point where it's not worth using anymore... Well read the link, it explains it better than I do!

 

[nephron]

My bikes have excellent throttle response with avgas

I doubt it. AV-GAS has special flight requirements, primarily de-icing agents (huge, aromatic compounds), conductivity additives, corrosion inhibitors, etc. This results in a larger carbon number distribution than race fuel (which use small, volatile compounds for obvious reasons), which results in a very, VERY important property of airplane fuel: low volatility.

WRONG FUEL. Race fuels use not only TEL for antiknock inhibitors, but use very high energy small compounds (3-5 carbons) with at least one double bond (eg, Isoprene) to raise octane even further, WITHOUT screwing up the distillation curve for the application. The distillation curve is much more suitable to racing and high rpm requirements than AV gas. If you look at the carbon number distribution vs. fuel distillation points, you'll find that as the carbon number increases, the endpoint temp increases. Typical AV gas and gasoline from a pump have endpoints around 400 degrees, which is why you spooge on the trails, and also why I don't use that crap anymore. ;)

 

[muddy226]

What about the relationship between ignition timing and octane ? I always thought that knocking/pinking was caused by the timing being too advanced when using lower octane fuel, and that if there were no problems with pinking a higher octane fuel wouldn't make any difference. I am ignorant about fuels so always use "super unleaded" ( Shell Optimax ) in my RM250, with no problems. However I did buy a few cans of Silkolene "Pro Boost" to try, and it made a nice smell and seemed to make for cleaner running, but no other difference. I tipped some into my car which has all the electronic gizmos like anti-knock sensors, variable length intakes etc and it accelerated much faster.The main point of this though is that after reading through these posts I am concerned about what I am putting in the tank, as it doesn't say on the can. Can someone tell me please what is in Pro Boost ? Thanks

 

[marcusgunby]

I know its main ingredients are MTBE and tulene as i e mailed there tech support-i used it in my modded 03 KX133 after it blew due to detonation-it never blew again, however i did mod the head at the same time to be less aggressive in octane demands.

 

[380roost]

Checked the specs for Exxon Mobil 100LL AVGAS, they list the final boiling point as 170C (338F) maximum, is this the end point ?

 

[Rich Rohrich]

Originally posted by 380roost
, is this the end point ?

Yes.