azzkiker23

i was wondering if 101 octane would be safe to use in our cars?

Nashua_Night_Hawk

if unleaded yes... otherwise it's NO. I used unleaded 103 racing fuel at the drag strip and it did not help. maybe if you are use Nitrous, SC or a Turbo.

allmotor_2000

I have used VP Motorsport 103 (unleaded) and its fine to use!

Juker008

Correct me if I am wrong, but the higher u go in octane the more lead is present in the fuel.

Just like with a bottle of octane booster, all it is, is a bottle of lead.










Juker008

CO-CL-S

Lead is not in unleaded fuel. The lead was there to protect things like valve seats. Octane is the ability of gas to not predetonate(?), thus allowing a higher compression, etc. to be built up prior to the plug firing. The lead was removed because it would eat up catalytic converters. YMMV

Deathlok

keep in mind also that unless you are specifically getting knock/detonation that is forcing your engine to reduce power to prevent it you will not see _any_ gains with higher octane gas.

In other words, if you're making 200hp with 87 octane, you'll make 200hp with 100+ octane.


As an aside, in cars octane boosters usually are some combination of Toluene, ethanol, and MTBE; none of which contain lead.

Now, what you want to avoid is _airplane_ fuel which is often leaded and definately not recommended for vehicle use, regardless of the octane.

paper1122

Yeah, the octane number is the measure of the knock resistance, basically you won't see any difference, since our engines are designed to work best on 93. If you use a lesser grade the engine management system automatically reduces the compression ratio of the engine so that you don't get autoignition. But the compression ratio won't be increased when you add higher octane gas. So basically, don't waste your money.

allmotor_2000

Compressio ratio is a constant that is physical to the volume of air displaced by the piston and the piston-shape/combustion-chamber volume. The PCM can retard the timing if it senses 'knock' or 'ping' - usually called detonation, pre-ignition etc.

There are other factors that can cause knock... say on a very hot day - so under 'ideal' conditions and 93-octane you won't see any benefit from using 101-octane - but on a not-so-great day, you probably will see some benefit. In CA where 91-octane is pretty much the best gas available, 101-octane might be more beneficial.

dfreder371

Juker: You are incorrect. Lead is a lubricant that is used for the valves and valve guides.

Before all you PhD chemists jump on me, here is a VERY MUCH SIMPLIFIED explanation of octane ratings. Gasoline is basically two chemicals, toluene and octane. 87 octane fuel is 87% octane and 13% toluene. I think you can figure the others out. To get above 100 Octane, more volatile components are put in the fuel, such that you can surpass the relative top of 100%.

A warning here (and this comes from an airplane pilot, me): Stay the hell away from our avaition 130 octane low lead! In a very short time, you will need a new engine, if not just a valve job.

Our car engines are very tight. Clearances of .001"-.0005" are common. Due to the vast heat expansion/contraction of air cooled aircraft engines, the tolerances are more on the order of .007"-.009". This is why airplane engines are hard to start, as compared to cars.

Back when we COULD buy leaded gasoline, 130LL was introduced for aircraft engines, and that stuff was RELATIVE to airplane engines. Although it was called 130LL, it had five times the amount of lead car engine gas had.

All of this makes me shake my head after lifting off, and hitting about 50 or 100 feet above ground, there sits some stupid ass in his ferrari or lambo, gassing up on 130LL. Dumbshits.

Deathlok

Toluene is actually around 114 octane as I recall.

dfreder371

Death: I did say very simplified! For the masses. There is much more to this subject. I just didn't want anybody wrecking their car engine with airplane fuel.

Juker008

Hmmm ok guy.

Now explain something else to me, why is it that higher octane fuels commonly found at race tracks are leaded. I can't remember if it is 100 or 103 that is the highest octane fuel that is unleaded, but when u go higher than that the fuel is unleaded. Why is that? Why can't they make a 1xx octane fuel that is unleaded.






Juker008

typeR

there's 105 unleaded


http://www.racegas.com/fuelspecs/default.asp




One of the highest octane unleaded racing gasolines available! Sunoco GT Plus Unleaded is specifically formulated for the professional racer and should not be used on the street. It is highly oxygenated to help produce maximum performance in classes which allow high dielectric fuels and is an excellent choice for modern computer-controlled applications which cannot otherwise tolerate tetraethyl lead (TEL). Sunoco GT Plus Unleaded is recommended for applications up to 12:1 with domed pistons and 14:1 with flat top pistons.

Fuel Property Typical Specifications
Specific Gravity 0.735
Antiknock Index (R+M)/2 104
RON, Research Octane 109
MON, Motor Octane 99
Reid Vapor Pressure 9
Distillation, ºF .

Initial Boiling Point 100
10% Evaporation 135
50% Evaporation 200
90% Evaporation 230
Final Boiling Point 255
Oxidation Stability, Min 1440+
Copper Strip Corrosion No. 1
Existent Gum, mg/100ml 1
Leaded No
Color Lt. Blue
Oxygen, Wt.% 4.5

Deathlok

The short answer is that the lead acts as an octane booster.

(As I recall, something like .4 g/l provides a boost of like 5 RON or somesuch).

I'd assume it's just one of those things were gasoline + toluene can only take you so far and lead increases that. As was said before, you wouldn't want to run it in your street car!

Juker008

Nice Tnx TypeR.

Deathloc, I think u said it. Toluene can on ly get octane so far, lead must then be added to go higher.







Juker008