macnewma

I would like to know who here uses any of these octane boosters or race gas.

After talking to a local mechanic, he suggested that when running higher than stock boost with my 951, especially on the track, to use race fuel. The only problem is that I don't know where to find race fuel (aside from the track) and it is damn expensive.

I can get 94 octane pump fuel here, but I am thinking about using toluene/xylene. I have read the RacerX stuff and all of Danno's comments. I have also read that these chemicals can eat at fuel system components. Anybody have any opinions on the viability of a 10-30% toluene/xylene mixture?

Thanks,
Max

Darius Juca

I live in Ca, state of the crappyest gas....I use toluene/xylene but find it does better with race gas and pump gas mixture....
I recoment using Toluene sice it's not as corroasive as Xylene...I use 20 procent To/Xy mix.....

porshhhh951

I have used toluene before works great on a 10% mix of half a tank of fuel. I also use 104 unleaded from a local speed shop. It's my understand that leaded fuel in our car's is okay so I have use c16 and other various product's that are leaded....anywhere from 104-117 octane rating's on various mix's. Mostly I use 104 unleaded. Most of my friends use toulene or xylene mix with 93octane...normally anywhere from 10%-30%mix.

Sam Lin

I run either Xylene or Toluene mixed, but in lower quantities than most - I add a gallon to a full tank of gas. On the crappy 91-octane AZ gas, gives me just over 93 usable octane, which is all I need - a bunch of us here do it. It's not really to allow us to run a more aggressive tune or boost here - our summer gas is so poor, our tuning maps that are great in winter knock like crazy in summer even with richened A/F and retarded ignition.

Sam

MildMax951

I run a mix of leaded racing fuel and pump fuel in a 2:1 ratio.
There is only one spec of race fuel available in South Africa and that is
102.6 RON (governed by the local motorsport body)
Our pump fuel is, wait for it, 93 RON thats what you call 88 Octane (R+M/2) in the USA.

Looking on the light side at least I don't have to ponder the question "Do I boost octane or not", I have no option but to do it

special tool

I have using 12% tolene for YEARS. It doesn't eat a Goddamn thing in the fuel system. All it does is: back off detonation, increase specific gravity (enrichen) and increase flame front speed. That's it. Use it.

Dark Lightning

Bear in mind that "octane boosters" raise your octane level by a handful of points. What's important to note is that in the world of fuel, the term "POINTS" refers to TENTHS OF AN OCTANE. If the boost offers 5 points, you just went from a tank full of 93.0 octane to 93.5 octane.

Short & sweet: octane boosters are useless.

MildMax951

Sorry to drag this off topic, but some octane boosters do work.
NF (Nitrous Formula) Race from Australia in the black bottle has been independantly tested in Australia. The Subaru owners club in South Africa had it tested as well, added at full dose to our 93 RON crap it raised it to about 96.5 RON
Thats THREE RON NUMBERS not points. On the downside it contains a sh*t load of MMT , the detrimental effects of this to your engine are an ongoing subject of debate.

toddk911

"Short & sweet: octane boosters are useless"

yep, and it pisses me off that companies are making millions off ot the stuff

I use xyl/tou also. Mostly Xylene as it is 118 octane, vs 114 for Toulene both being about the same price. I don't run it that often, but when I do that is what I use usally a 20% mix to 93 octane. Like 1 gallon to 1/4 tank of gas. And from what I have read and been told by Danno is that xyl/tou are both completely safe and do nothing to harm your fuel system. Especially because the majority of our gasoline is Toulene, with other chemicals thrown in to "tone it down". So basically, the lower the octane at the pump the less Toulene that is in the gasoline.

Also, what is the formula again for what % = how many more octane?

OriginalSterm

a couple of things...

if you are concerned about "eating things up" with xylene or toluene, i heard a little bit of marvel mystery oil takes care of that

is the stoichiometric a/f ratio for gasoline, or gas/xyl/tol mix the same?

leaded fuel is ok for these cars, as long as you don't mind the O2 sensor having a shorter life. how much shorter, depends i guess.

macnewma

Thanks for all the feedback guys. I am definitely leaning towards using Toluene.

As far as using leaded gas, I have heard that, over time, the lead also coats the turbo wheel and throws it out of balance, destroying the housing. Any truth to this? The guy that told me this said he had not heard of it happening on 951s, but he mainly works on 930s.

What kind of prices is everyone getting there Toluene at? Where is the best place to find it cheap?

Thanks,
Max

MildMax951

My car has run on nothing but leaded gas for all of it's 17 year life. My turbo is a little smokey at high revs but otherwise seems in good nick, generates 20.7 psi (gauge pressure) boost by 3250.

As an aside when my factory wastegate was removed recently after a life time of leaded fuel it was still in good condition, so I decided to ignore the little yellow tag attached to my new Tial wg stating that it wasn't suitable for use with leaded race fuel

SamGrant951

Max, Im calling Home Depot's and ACE Hardwares right now, Ill post here if I find someone that has it in stock.

Danno

"is the stoichiometric a/f ratio for gasoline, or gas/xyl/tol mix the same?"

It's the same, but the density is not, so that can change your mixtures. Both xylene and toluene has higher density than pump-gas, so the end result will be a richer mixture. Which isn't too bad, much safer than AvGas which has lower density that pump-gas, leading to a leaner mixture. However, in the low percentages used, 10-30%, the change in density by adding xylene or toluene won't be that significant.

Xylene (117 octane) is easier to find. It's often used as a cleaner and solvent for cleaning paint off brushes and stuff. Toluene (114 octane) is used to cut lacquer thinner and is tougher to find because it's used in meth production. Specialty paint stores will have it though, like Sherwin Williams.

"Also, what is the formula again for what % = how many more octane?"

Use a weighted average:

Octane = (114*GallonsToluene + 91*GallonsPumpGas) / TotalGallons

So adding 2 gallons of Xylene to a 20-gallon tank would give you:

Octane = (117*2 + 91*18) / 20 = 93.6 octane

SamGrant951

Indianapolis / ACE Hardware: (Toluene)
E 62 St has it, not sure what size - Im heading there after work...
Westfield branch only has quarts...
Carmel Branch: 731 S Range Rd has the gallons in stock ($9.99)

Home Depot in Noblesville has Xylene, but not Toluene.