DirtRider . Net MX, SX, Arena Cross, Off-Road Community
Dirt Rider . Net Text Version Home
Dirt Bike Dirt Bike Dirt Bike Dirt Bike

This is the text version of DirtRider.Net
Click Here for the Full Version


Pages: 1

Home brew octane boosters

(Click here to view the original thread with full colors/images)

Posted by: Shawn Mc

Rich, Ive seen several recipes for octane boosters using Toluene and Xzylene, and light oils. What is your view on these. Ive been thinkin about it, since Toluene is mostly what missing out of pump gas these days, and its only 2 bucks a gallon as opposed to 3.95 for a 16 oz. can of octane booster that only gets you maybe 2 points (from 92.1 to 92.3) ave. Ive seen recipes for mixes that will get you to 99.5 ave. using pump gas, for a lot less than VP red or C-12, without having to use oxygenates, to further confound my jetting.


Posted by: MikeS

Search the posts for toluene....you will find it is a bandaide fix only. Throttle response will suffer when too much is used.

As for what pump fuel is missing.....it may me alot more than you mentioned.


Have fun brewing...be safe and leave it to the experts


Posted by: Rich Rohrich

As Mike pointed out, it's been covered pretty well in the past. Here's a couple of threads to get you started:
http://www.dirtrider.net/forums3/sh...eferrerid=16241

http://www.dirtrider.net/forums3/sh...eferrerid=16241


Posted by: DEANSFASTWAY

Isnt toluene a main ingredient in paint thinner?


Posted by: Rich Rohrich

Quote:
Originally posted by DEANSFASTWAY
Isnt toluene a main ingredient in paint thinner?


In some versions it is. Industrial grade Toluene has a ton of impurities in it which makes it unsuitable for use in engines. Of course that doesn't stop people from dumping it in their fuel.


Posted by: Shawn Mc

The mixtures ive seen are 20% toluene to 80% premium 92 pump gas. And from what Ive seen, its the main ingredient in off the shelf Octane boosters like PJ1 on others. They only recomend a 16 ounce can to 5 gallons of fuel. I ran some PJ1 at glamis once in my CR500, because I ran out of the 50/50 Trick 108 and pump gas I was running, and Id swear my bike ran crisper, which it may have considering what Ive been learning. I just wonder how much throttle responce Id loose, or if Id even notice on my 426 with the BK mod and thunder alley pipe, with the TPS re-adjusted? Normally I run 100 octane 76 unleaded, @ $5 a gallon. My jetting is crisp now, just lookin to save some dough.


Posted by: Rich Rohrich

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 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 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 YZ400, and a 94 mm 13.25 compression YZ417. I used Amoco Premium MTBE based (non-alcohol) 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.


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.


Posted by: OKKX'er

Thank you for your efforts, Rich. You answered many questions I had.
Not the first time, either.


Posted by: cujet

Just slightly off topic, I use toluene in my turbo miata. I ran it last week at 50% toluene/chevron 93 with up to 22 pounds of boost non intercooled. Without the toluene the non intercooled limit is around 8PSI boost. I was also able to add 5 degrees more timing total and about 4% more total fuel. There is no other way I know of to gain as much power. I have tried all sorts of race fuels and combinations, none are as tolerant of high boost without detonation.

By the way Rich, I use the industrial stuff available in 5 gallon metal containers at the local auto paint store.

Chris


Posted by: Rich Rohrich

Chris - As you and I have discussed before, when you have an abundance of intake heat to work with as you do in your non-intercooled turbo application the rules are a bit different. I think a big part of the reason you are having good luck with this combination has to do with the extremely high end point vaporization temps of industrial grade Toluene. Even with the high intake temps there is a good chance that some of the fuel is still passing through to the combustion chamber in liquid form. Pump fuel tends to have a lot of trash in it with high end point temps as well. Large droplets of fuel that make it into the combustion chamber can lower the piston crown temperatures significantly. Detonation is driven by heat, so anything that lowers combustion temps can have a major influence. There is a very good chance that a higher octane fuel that vaporizes completely would be more likely to knock than your setup, so it's not surprising that this combo is working for you. Back in the turbo F1 days Honda ran a custom Shell fuel that was 85% Toluene, so there is certainly strong evidence about it's value in turbo engines.

Unfortunately the same characteristics that make Toluene so attractive for forced induction applications makes it poorly suited to high rpm, short intake tract motorcycle applications running normally aspirated. Like so many things it's a trade off. Whether or not it's a good one depends to a large degree on the application.


Posted by: cp380sx

I have seen the MSDS on Phillips B35 and B42. Suprisingly the B35 has as much as 40% Toluene in it whereas the B42 contains as much as 30% Toluene. Normal pump premium is around 20% Toluene. It appears the most of the unleaded race gas on the market is using higher percentages of Toluene to get the octane number up.


Posted by: cujet

Yes Rich, you are correct. The toluene is ideal for turbo engines that have very high intake temps. As far as the large droplets of fuel finding the piston crown, that also seems to be likely as I have to increase the overall jetting by 4% to get proper results.
In addition I have no real way of measuring the affect of toluene on throttle response. The increased timing allowed by using the funny fuel mixture drasticly improves the throttle response. In addition too much octane for a given situation seems to soften throttle response. So I would guess an 8 to 1 Comp Ratio 4 stroke would not respond as sharply to 115 octane as it might to 87 octane pump gas.

Chris


Posted by: Rich Rohrich

Quote:
Originally posted by cujet
In addition too much octane for a given situation seems to soften throttle response. So I would guess an 8 to 1 Comp Ratio 4 stroke would not respond as sharply to 115 octane as it might to 87 octane pump gas.


Octane number isn't the issue. The component makeup of the fuel and how well the distillation curve of the fuel matches the application will determine throttle response. Phillips has an interesting spec with their race fuels called a Driveability Index. It's a spec that compares throttle response between fuels. For reference their 118 MON octane fuel B37 has a 15% better driveability index than Illinois summer blend 87 (92 RON / 82 MON) octane pump fuel. Their MTBE oxygenated B35 (100 AKI) is rated at > 25 better than 87 pump fuel. Of course these numbers are based on normally aspirated operation. Compressing that air and jamming it in at high pressure puts a fascinating spin on things and demands it's own set of rules. Can you tell I LOVE turbos?


Posted by: cp380sx

Quote:
Originally posted by Rich Rohrich
Compressing that air and jamming it in at high pressure puts a fascinating spin on things and demands it's own set of rules. Can you tell I LOVE turbos?


Same goes for nitrous oxide and supercharged applications. I mix 20-30%Toluene w/ pump premium for my nitrous injected Corvette. When you are making 600hp and 700ft/lbs of torque, throttle response is not an issue. Putting the power to the ground is the hard part.


Posted by: Aholland

I once had a Suzuki GT750. It was a 3 cylinder 2 stoke 750 cc street bike. I purchased a 45 gallon drum of naptha that I used to increase the octane level on the bike. To make a long story short, I was successful in increasing power if I did not use a mixture of more than 10%. By 20% I was spitting flames out of the rear pipes and the power had dropped off dramatically. Nice show....but no go.... It appeared to flame up too easily and had not enough anti ignition properties. All things considered, I would not use it again. I have had better success using AMsoil synthetic oil at 75:1 mixture. No fouling/smoking problems and better snap at the throttle. I believe the lower oil content in the fuel equates to a better "effective" octane level and better power.
Alex


Posted by: flyinzuki

I've been following this thread, it seems to be related to
my brothers current project. Turbo KLR 650.
It's about 80% complete, it runs and starts to spool-up,
but that is as far as we have gotten, oiling and exhaust
are all that is left.
Since this is a draw through set up it's going to super-heat
the fuel-air mixture. My 3 available fuels are pump super,
100LL, and Tolulene. What would be my best choice, or
blend, considering we just want to keep the stock motor
together. I was planning on the 100LL for it's cooling effect,
but this Tolulene/super mix has me intrested.


Posted by: Shawn Mc

Flyinzuki, Id go with a 20% mix of the toluene and pump gas. Although, your compression ratio is a potential time bomb. If its more than 8:1 go really easy on the boost. Id say not more than about 4-6 lbs total. I had a small block chevy truck with a draw through Martin-Accel turbo system on it, and for boost limitation, they used a recirculation-popoff valve in the intake manifold. I had the compression at 8.6:1 and the max boost was 8 psi. I would detonate pretty hard on pump 92, with 36 degrees total advance. I had to back the timing off or kill the boost, one or the other, on the pump gas. Like cujet, id use the toluene, and be able to jack some more timing into it, and allow the boost back up, and really make some major power. Its ok around town, but its a pain in the buttocks, when your on your way to the river.


Posted by: cujet

My testing shows that you will be able to go as high as you dare with the boost level using the necessary amount of toluene. I use 50% at 22LBS boost, NON intercooled 9.4 to 1 compression!

Chris


Posted by: flyinzuki

That's good to know considering he doesn't have a wastegate:scream:...yet.



This is the text version of DirtRider.Net
Click Here for the Full Version

Text Version Home





vBulletin Copyright ©2000 - 2009, Jelsoft Enterprises Limited.
vB Easy Archive Final ©2000 - 2009 - Created by Stefan "Xenon" Kaeser