Just curious what you guys feel is a good octane boster. I've been putting a can of lucas octane booster in before I go autox. Any other brands that might be better or cheaper?

why?

Andy

Dave said I should so I do!

I don't think the tank additives are true Octane boosters. Just kind of a bandaid or snake oil. I think to truely "boost" your octane you gotta buy race-fuel like Trick, Turbo Blue, or the 108 stuff Sunoco sells.

I would like to 2nd the "WHY"
If your car runs on rat piss from a regular pump then adding Octane boost will not make it run better.
actually lose HP because the higher octane burns slower. which is less bang.

If you car is running better than 9.5 to 1 compression you should be able to use super unleaded rat piss.

If it pings then up the octane which would be required everytime you get gas. $$$$$$

I would agree with above comments unless you have substaintially higher compression ratio than stock.

Not even sure what pinging is. I mean I know what it is but wouldn't know if it was unless it's something pretty dam noticable. I think it is 10.5:1 might be 11:1

U ses to be able to get 94 but only 93 now. Haven't seen 94 in awhile

That sounds high to me. Mind you I'm no expert.....

I would think if you were at 11.0:1 without a knock sensor, you would have to run race gas.

Hay Joe;
Is there any particular oil company that sells that RAT PISS? Or is that a general statement? Or did you just give away your best speed secret.
Dave

this is kind of an intereting article on the topic:

http://www.hotrod.com/techarticles/72498/index.html

Well uh the average "rat piss" clogs up my fuel filters has lots of water in it and is good for my Lawnmower.
I try to buy Shell V power 89 on my way out of town to an event. (usually about 3:30 am Sunday mornings). Or Chevron

We had a real bad problem right after Katrina. alot of stations had the pumps relocated 2 blocks inland. Open pipes to the tanks below. you get the picture.

I also try not to buy gas if there is the tanker truck filling up the station tanks.
Just seems to me at the rate of fill that any sediment in the tanks is stirred up and then dispensed thru the pump.

So far it works for me wether it's bunk or not.

Alcohol spray system, or Water/Methanol. Not cheaper, but a hell of alot better. That stuff will boost 91 to over 100. Suby guys use it all the time and it eliminates knock all together. SMC makes a great one. It will replace your windshield wiper fluid container.

the answer, NONE.

So called "octane booster" took my car from perfect running daily driver, to sitting, requiring attention on stands...

Hmm, hot rod article WAS a good read. answers the question about "rat piss" too....

But like I said the engine being tested was ment to run on higher octane fuel. 10.4 :1 damn. however I know of a hopped up street mod Civic hatch running 13:1.

He so hates getting his ass kicked by a VW.

The cheapest oxy booster is just buying toulene at your local hardware store, by the gallon.

But again, probably not needed unless you have built your self a race engine. The is a fair amount of info on line about mixing your own oxygen booster. Any of the pre-bottled stuff you buy at the flaps is a total rip off, and basically does nothing.

To be sure, your mileage may very...

Zach

I use Torco Race Concentrate- the leaded stuff :-) I forget the mix, but it blends 93->98 with about half a bottle (~$16/bottle). It also helps the gas burn cleaner. The same goes for Redline SI-1- this product doesn't boost octane, but it is the best fuel system cleaner you can buy (they also make a version with lead substitute). Pull the plugs after running a bottle of that and they almost look like new. In fact, I need to pull mine after my 800mi run this weekend to see what they look like.

I use 100 octane gas from gas station in San Jose in my new Turbocharged Mazda. Makes a huge difference whenever I go from 91 to 100 octane in that car. Probably at least 15-20 hp jump and engine management system allows for more boost at higher RPMs too.

Using same 100 octane gas in my 914-6 doesnt make much difference. I was hoping that my engine had a little higher than stock compression, but I dont get any pinging with 91 octane.

Grant, your modern engine has an engine management system with a knock sensor. It retards the timing and (much more importantly!) reduces the boost when it senses pinging! The 914 has no knock sensor (and most of us have no turbo) so the timing is set where it is, and that's that. Modern engines can run closer to "the edge" for better performance, while the old-fashioned ones have to leave some safety margin so they don't ping under normal everyday conditions.

Running higher octane than is "required" in a modern car can (in some cases) make a real difference. In a 914, it's a waste.

BTW, my best description of what pinging sounds like is a "spitting rattle" sound.

--DD

i'm sure grant knows all of that. has anyone every experimented with using toluene as an octane booster?

I'm thinking i might pick up gallon at the hardware store and experiment with timing.

i agree with dave,
see the article here.... http://en.wikipedia.org/wiki/Engine_knocking

unless you plan to adjust your timing to match your octane every time you fill up, it's not worth it.

if you run advanced timing for the octane booster and then fill the tank with rat piss you will get detonation/ping.

if you time your car for rat piss and then add a high end solvent like tolulene or xylene, you will have too retarded timing and possible burnt exhaust valve/high HC/possible reaction with rubber gaskets and seals in fuel system...

i like the injection method..... stand alone and no knock sensor needed.

More octane just makes a faster burn. If your engine is not designed for it with timing, combustion chamber design, and static compression, you wont see any gain. In fact you'll probably lose fuel economy.

higher octane burns slower IIRC....

thus more advanced timing.....

right?

my understanding (and i am not a chemist) is that octane rating does not necessarily have to do with the speed of burn, but simply its resistance to predetonation. it's common for people to say that 87 "burns faster" than 92, but i think that's just a popular misconceoption -- 87 will ingnite under compression before 92.

in other words, it's possible to have high octane (highly resistant to predetonation) and fast burning fuel (e.g. race gas). the 92 you get out of the pump shouldn't be any quicker/slower burning than the 87.

again, though, i'm not a chemist...

Read the article that was linked-to above. You'll see that they found different formulations to burn faster or slower and that those had little or no relation to the octane rating of the fuel.

--DD

I mix 2 gallons of 110 race gas with each fill up before a track day.
Works out to about 94 octane. car runs great, cool and makes good power.

better than straight 91?...don't know.


KT

Yeah, you're right. I got it mixed up.

I just know you have to design an engine around the octane rating (or type of fuel). I understand octane boosters to be the same type of "liquid engineering" found in Mobil1... that is a gimmick.

Most (all?) racing organizations specify fuel.