Anyone do homebrew race gas?
 

Here in California (San diego specifically) we get 91 octane gas. The problem is that the gas is more like piss and may as well be 87. I know that there is a lot more potential in speed's here with just better gas. I ran for 2 tanks on a mixture of our 91 and VP racing 110 unleaded to get a blend of between 94 and 96 octane, and the car was so much stronger at all times, it's not even funny. That said, unleaded race gas is expensive and leaded race gas will FUBAR your o2 sensor.

So, doing some research, before CA and other states banned MTBE from gas due to cancer links, there was a high concentration of MTBE and Xylene in gas. Xylene has an octane rating of 114 (R+M/2) and costs around $6/gallon when purchased in 5 gallon drums.

Assuming 91 octane costs $2.6/gallon and Xylene costs $6 gallon, it takes 2.5 gallons of Xylene to every 11.5 gallons of 91 giving you a blend rating of 95 octane at $3.21 a gallon.

If I did the same blending with 110 VP race fuel (even at my dealer discount) it would cost me $4.08 per gallon.

The sentiment is that you can run up to 30% xylene without problems, but keeping it around 20% (which is where I will be) seems to be the intersection point for performance and safety.

Any thoughts?

try meth injection

Just make sure when you add xylene of toluene, you add 1 oz of Marvel Mystery Oil per every gallon of either X/T you add. The stuff dries out o-rings like a mother without it.

Ive experimented with 2% nitromethanol added to race fuel and gained almost 3/10ths of ET by doing so. But, you have to turn down timing as it really leans out. 1 Gallon of nitro costs me about $55.

In the end, meth injection is the cheaper alternative to our shit fuel in CA. 5 Gallons for roughly $30, mixed with 50% distilled water, gives you 10 gallons of fuel at a cost of about $35. That will last you several months and net you good octane levels, while also cleaning out this dirty ass engine.

Meth injection requires a whole set of hardware though. While it may be better over time, it seems much less convenient than the xylene route. I did plan on using the MMO also...

Well theres an initial investment, but if you add up the cost over time using the Xylene route, you will find that meth injection is a cheaper solution and easier in the end.

Ive been drag racing a long time and vehicles i race, aside from the MS3, use race fuel with custom mixtures. When i drive these vehicles on the street, i run meth for octane purposes and mild cooling. Nothing beats race fuel for the track, but on the street, nothing beat alky injection.

You can also use Denatured Alky in pure form as well. Its pretty cheap at the big chain hardware stores.

Whoa your still here? I thought all the things people say about you drove you out.

a little hatorade never bothered me...

We should be best friends glock23. i think i love you.

I would vote for water/methanol injection, too.

I recently added a half tank of 100 octane racing gas to a half tank of 91 for an overall octane of about 96. The engine runs smoother, quieter, and stronger no doubt. I'd love to keep it running like this all the time. It has cut my knock retard in half (I'd hoped it would eliminate it) and added a few more degrees of timing advance--overall I'm seeing 8 degrees of timing advance where before I saw only 4.

But at 8 dollars a gallon, adding racing gas is not a long term solution. I can't do $80 dollar fill-ups every week. Nor do I think supplementing with xylene or toluene is a real solution either. My brother has had good results with toluene, but again, the cost adds up over time. I'd have to add about $30 worth of toluene to each tank to get up to 96 octane. After a dozen fill-ups (i.e. 3 months) I'd have spent the cost of a decent WAI system. And it sounds like the cost of consumables is a factor of 10 less with WAI vs toluene.

It costs me about $7 extra per tankfull to run 100 octane 24/7.

I use Torco race fuel concentrate additive.
My car still does not know what knock is, or i have a bad sensor.

100 RON maybe.. but here in the US we grade our gasoline based on AKI (Anti-Knock Index), which is the average of RON and MON. and AKI are used interchangeably here, a fact that Torco apparently overlooked... :rolleyes:

To get close to 100 Octane (99, anyway), you'd have to mix it with 93 Octane pump gas in a 1:20 ratio, which is almost 3 quarts in our 14.5 gallon gas tanks. This would cost you about $30 dollars per fill-up at current prices. Don't tell me you've found a source for Torco at 75% below retail?

That is good info you brought up never seen that.

Whatever octane it is i have yet to record 0.01 knock on or off the gas or like i said
before i must have a bad sensor.


I pay $84.00 for the case of 6-32ounce bottles. I dont buy 5 gal pales cause they tend to go bad.

Had to edit cause i made a mistake with the octane rating.

Well I hope that trend continues for you.

I'm getting knock up to 4 degrees under load on a 50/50 mix of 91 and 100. I may have a bad sensor, too sensitive. That or my pistons could be dirtied up from lots of stop-and-go driving in the heat. I'm thinking to install water injection to try to keep things cooler and cleaner.

Well, my xylene arrives tomorrow, so I will report back with any changes in spark advance and feel.

I am going to do about 1.5 to 2 gallons of Xylene and add about 4oz of MMO.

I added 1 gallon of Xylene to about 8 gallons of 91 octane and about 4oz of MMO. That gives an octane rating (R+M/2) of approximately 94.5. The car feels great. Spark avance is great and no KR, even in 6th on the freeway if you get on it a little.

Hey im thinking about running xylene in my car since its kinda easy to get up here in canada for some reason but what is this marvel mystery oil you guys speak of?

::Marvel Mystery Oil::

It keeps the rubber from drying out and cracking

Thats really all thats gonna happen with this stuff in there? one of my friends used to run xylene every tank in his audi with out any oil and hes getting a 335i and hes gonna run it it there, i just want to make sure is all. What other oils work instead of that mmo stuff. Its hard to get everyting in canada for some reason.

Found this after looking on line for a few hours and its fairly close to yours dabears.

Xylene
R+M/2...117
Cost...$2.75/gal
Mixtures with 92 Octane Premium
10%...94.5 Octane
20%...97.0 Octane
30%...99.5 Octane
Notes: Similar to Toulene. 12-16 ounces will only raise octane 2-3 *points*, I.e. from 92 to 92.3. Usually mixed with Toulene and advertised as *race formula*.