What the best gasoline mix to use?

[Jamo]

Do you have a gas tank or are you running a fuel bladder?

The octane boosters will eat a bladder up over time...alcohol not good for the rubber.

[CSX 4039]

BTW- thanks for the link on the lead additive. It sure seems to be important, as I recall all the hoopla of "Regular or Unleaded" 30 years ago. I realize the problem with lead is the catalytic converter, but I wonder what the difference in a 1965 valve from a 2008 valve that the old valve "requires lead"? Is there a difference in the valves, or just an octane boost? The link you forwarded also seems to suggest (naturally) that it is really important to run real lead. My 1966 FE was, of course, rebuilt in 1997. So, do I have "lead neccessary valves", or "unlead tolerant modern valves"?

[CSX 4039]

Originally Posted by Jamo

Do you have a gas tank or are you running a fuel bladder?

The octane boosters will eat a bladder up over time...alcohol not good for the rubber.

42 gal fuel cell, I believe.
So, if there's rubber in there, then what?

[Jamo]

Fuel Safe and other mfgs will tell you whether your bladder can take the alcohol additives found in off the shelf octane boosters (that's how they reach the higher octanes rather than with real lead). Some can, but they are usually special order items, and if your bladder's been in there awhile (I presume it has), it likely is not designed for the alcohol ingredients (had one literally fall apart in my first Cobra). Typically, the alcohol-boosted stuff will say "lead substitute" on the can/bottle...but read the ingredients list. In addition, most bladders have a replacement date...most are around five years, but newer designs can go much longer.

Take the plate off and read the labeling on the top of the bladder (should be near the connections), and check with the mfg. My guess is that you either have a Fuel Safe or ATL.

REAL lead works fine, as does aviation/racing fuels.

Some folks have had problems with their state's ethenol mixed gas.

[CSX 4039]

thanks!

[Jamo]

You're welcome.

[Excaliber]

A couple of thoughts on the subject come to mind. Octane boosters you buy from the store simply don't work. Now thats a controversial statement for many, but man I HAD an engine with 12.5 to 1 and 'been there done that' with just about every concievable combination of 'what ever'.

Heres a clue:
When the can says it raises octane by one point, that is 92.0 to 92.1. Gimme a break, thats so low any difference you could 'feel' would be a placebo effect, in my opinion.

Unleaded vs leaded:
Unleaded 'heads' have hardened valve SEATS, it's not the valves so much, it's the SEATS that present a potential problem. The seats can overheat from lack of lubrication (lead). HOWEVER, this really isn't an issue unless your driving at sustained highway speeds for several hours at a stretch! Which is very unlikely in a Cobra as they are seldom used for a 500 mile a day cruise. Those that DO drive their Cobras long distances at a stretch have all ready figured out the whole 'octane/lead' issue in the first place and have a handle on it.

Alcohol will separate in the fuel over time, so 'sitting' through the winter with alky gas mix is not a good idea. I've HEARD, cannot confirm, that Fuel Stabilzer does in fact help with this problem. Many boats have fiberglass fuel tanks, not something for most of us to worry about (a big issue in Hawaii though) and the alky will and does attack the fuel tank with really nasty results. Notably clogged carbs. I would think fuel cell degradation would first show up as a 'clogged' carb situation as well.

Detonation:
Certainly a number of issues come into play with the combustion chambers ability to deal with higher compression, lower octane and detonation. A KEY factor is 'quench' or 'squish'. More quench means you can run more compression with 'pump gas'. I specifically built my engine for good quench by specing the shape/size/aspect of the custom pistons to work well with my chosen heads/combustion chamber. I even spec'd the piston pin position to move the piston UP in the bore, bringing it closer to the combustion chamber 'quench zone'.

I am NOT an 'expert' engine builder by any means! I learned a TON from just hanging around Club Cobra and learning what questions to ask, how things work, etc. If I were to build the motor today I would incorporate even more changes, do some things differently as I continue to learn, right here, on Club Cobra!

[Jac Mac]

Just to clarify & hopefully not confuse on Excalibers comment above regarding ' overheating ' of the valve seats.
The lack of lead as a seat lubricant allows the closing valve to virtually ' friction weld ' itself to the seat each time it closes. The next time the exhaust valve opens the hot exhaust gases remove most of this ' broken weld ' material from the seat area of both valve & seat.

Now it is interesting that the problem is greater when the valve/retainer/lock assy is of the type that allows/promotes rotation of the valve. This system that was originally devised to help keep the seat area scrubbed clean in the leaded fuel era works against us in a performance type application. When we fit stronger springs & race quality valve locks/retainers etc we actually check the rocker to stem tip mark to ensure a single wear mark to ensure the valve train is stable with no spring surge etc.

I have found that combos built with race type valve train for Hi Perf street use show less seat wear than a similar spec engine with stock rotater type valve train. Seat erosion still occurs but not as rapidly as the stock setup.

[Ron61]

FWB,

I am guessing that you mean the Octane Supreme 130 that your link shows. I have never seen that and if that is what you use it should work well in my car which doesn't have as high of a Compression as some of the others, but does still have the original iron heads. If that is the stuff I think I will order a case of it to try as racing gas is now in the $9 dollar per gallon range even when you buy a 55 gallon barrel.

Ron

[RICK LAKE]

CSX 4039 You should have no problems getting way with just high test and a bottle or 2 of the octane booster. I have Aluminium motor, block and heads and 10.5 compression and run 91. If you are having problem with pinging, add a water injection kit from Snow. All you do is fill the tank with water and a bottle of windshield washer fluid. 50/50 mix. Works great for turbo and blower cars. You just run a little less timing in the motor. The motor runs cooler, and you only lose maybe 20HP inthe top end. Some people have said they have gotten up to 50HP more with running more timing. This will work on any motor. Just have to remember to fill the water tank. If you are at 11.0-1 you should be OK with a good carb and fuel system. Not letting the fuel get hot under the hood and on the way from the fuel cell to carb is important too. They sell hi temp hose covers to insulate your fuel lines and keep the temp down. Are you running a turnkey pan? The cool air from the outside of the car is better too. Try and seal the turnkeypan with form tape to the hood scoop. There is an issue with Aviation fuel. I believe it's a lubercate issue with either too much or too little. The other thing is you are not flying at 25,000 ft. If you are going to run in the 140mph range you will need a pilots license. Rick Lake Ps. Ennie is the one to ask about high compression motors and mixing gas everyday. He's been there and done that. He found out that in some cases less is more.

[vettestr]

Just tinkering here but hydrogen or actually (Browns gas) because it also contains 02 may be more than plausible. Good old Dad has been building his own hydrogen generators for about a year now with me welding up a widget here and there for the experiments he comes up with. He has a few of his cars with the best he has come up with running with great results now. His path is increased mileage and using it to supplement not run exclusively on H2. If only a supplement you do not have to deal with rust issues etc... A byproduct of all this tinkering has been increased HP and ability to run more timing. The HP increase is not like nitrous but is without a doubt noticeable driving or even riding in the car.

At first found it only stopped the computer controlled injection car from removing timing via the ECM from the factory basic standards. Now have found it likes stock/factory timing and a little more under load. The increase in HP is comparable to the air cond being on or off on his 4 cyl. 2006 Saturn but with 23% increased gas mileage !!

The part that peaks my real interest is not increasing gas mileage but the fact it allows no it likes more timing when under a load (increase is factory plus about 8*) and will not ping as it is a more dense/cool fuel charge. To hell with lower power and higher mileage I want to add this to an engine that has had the timing backed off and either had to add or mix for an octane increase just to make it run to its ability. Adding browns gas to a SBC with 15 pounds of boost makes it like pump gas and run like it was drum fuel = or it is not pinging under boost so can keep the timing that the knock sensor took out if when just running premium pump gas.

Seems to be working so far but I am just sneaking up on it. Distilled water to make hydrogen is cheaper than race gas... go figure, total investment to build or replace this mess would be about 80 bucks, its the pile of stuff that didn't work as well.

[FWB]

ron,

to answer you, yes octane supreme 130 is the product i use (religiously)
it is nothing more than a solution of suspended lead. this stuff works...period..

i see some of the other posts saying they add A COUPLE bottles of octane
booster. wow . to 16 gal i use 1\2 quart. so starting with 93 i end up
over 100. to address the pinging....detonation will only be heard as pinging
at the extreme of it..if you have a 10:1 motor or higher and you run pump
gas you are detonating....i have used racing fuel when i go to the track and i get the same results with the octane supreme. note the odor of your exhaust
when you run racing fuel......i get the same odor from my pump gas and the additive, not that this alone sells me but i equate this to having about the same blend. i have an 11:1 427 stroked to 468 stage 2 kc heads a 671 lift roller cam and 2 4 bbls i run 38 deg timing with an msd dist all my timing is in by 2000 rpm. i have trashed the plugs KC gave me with the motor ngk somethings i now run autolite racing plugs about 2 ranges cooler. with the additive you will need to read the plugs to see where your particular combo has its sweet spot....ok this is getting wordy

[Great Asp]

http://www.klotzlube.com/tech/KL-602.pdf

http://www.klotzlube.com/storeProdDetails.asp?pi=50

If you are "close" to detonation, this stuff really works. I posted the tech sheet also. My 418 ran just over 11:1 and needed it.

I recommend it.

E

[meat]

Originally Posted by CSX 4039

What do you think is the best mixture of fuel to put in these beasts? (In my case, '66 427 FE bored and stroked with something like 11:1 compression ratio). In my case the purpose is not for racing, but rather for tooling around town (with occasional moments of showing off).
50% aviation gas? (Someone told me "yes", someone else told me, "it's too dry- formulated for 30,000 feet altitude"- whatever that means)

100LL general aviation fuel will probably cause a lean burn condition in your engine, which will cause all kinds of bad things to happen (obviously, you're probably not too worried about burning out a cat or an O2 sensor, but it really is made or airplanes). Also, it's got lead in it (more than racing fuel).

Jet fuel is diesel. Don't use that. It would be bad.

Originally Posted by CSX 4039

50% racing gas? (How do you really know what's coming out of that 55 gallon drum- hell, it could be french fry oil- these guys know I'm not a regular nor a racer).
93 octane with 4 bottle of octane boost? (42 gal. tank)
Real Lead (can you still get that stuff?)
Copious amounts of Sta-bil?
What's the best bang for the (big) buck?
I suppose this has been discussed before, but I did a search but the number of times "gas" comes up is nearly infinite.

The Meaning of Gas

Originally Posted by Rick Parker

91 octane seems to be the max in sunny Calif.

Where is that 100 octane Chevron White pump? THAT was some GOOOOOD stuff!

Competition 100 Unleaded Racing Gasoline

Originally Posted by Jamo

Do you have a gas tank or are you running a fuel bladder?

The octane boosters will eat a bladder up over time...alcohol not good for the rubber.

Neither is ethanol, which is what many companies are now adding to their gas. It eats rubber and plastic and makes the price of milk, corn and everything else go up. We should get rid of it completely and use Greeniehol: a synthetic blend of tree hugger, global warming hoaxist and con man. It may not burn as well, but I know I'd feel better burning it.

Your pal,
Meat.

[Excaliber]

Mix your own octane booster, here's some recipes. MOST octane boosters are little more than snake oil, with missleading advertisements, choose wisely. We were running Aviation gas for the Formula Ford race cars when the track was open. Jet sizes were increased to avoid a potential lean condition. Toulene, inhaled, through the skin, on your clothes for instance, can cause brain damage, just thought I'd mention that...

http://www.gnttype.org/techarea/misc/octanebooster.html

[meat]

Originally Posted by Excaliber

Mix your own octane booster, here's some recipes. MOST octane boosters are little more than snake oil, with missleading advertisements, choose wisely.

When did Shelby start selling octane booster?

Your pal,
Meat.

[Excaliber]

Good point Meat.

This is a really complicated subject with a ton of views on what does and doesn't work. On the link I provided above "Mix your own booster" it says the first formula (Formula 1) is straight Toulene. It states a 30% mixture will increase octane from 92 to 98.6. Another site I saw indicated something like a 14 to 1 ratio, 14 gallons gas/one gallon Toulene only raises octane by about 1.5 points ie 92 to 93.5. I guess you could do the math to figure it out. Bear in mind the commercial stuff works out to be a REALLY expensive method, not to mention hard to find and add when your on the road. I tell ya, you gotta reduce the darn compression somehow, someway, this additive thing sucks.

[CSX 4039]

It sounds like the overall "keep it smple" solution is brand name 93 octane pump gas with 2 quarts of Octane Supreme 130 per 42 gal tank (one ounce per gallon). I can do that! Thanks.
I wonder if there is a way to just buy the tetra ethyl lead from a chemical company without it being outlawed by the EPA?
$10 a quart. Cheaper than 100% race gas, but.....

[CSX 4039]

http://www.time.com/time/magazine/ar...728055,00.html

[427 S/O]

Toluene is 117 octane, you can buy it in 5 gal cans. Mix 8 gal. 93 and 2 gal. toluene and you got right at 100 octane. Use to buy 5 gal. toluene for about $16, not anymore!!!.