hey all, haven't posted anything in a long time, but i just had a question this LEAD SUBSTITUTE i found. on the front label it says
CD-2
super concentrated
LEAD
SUBSTITUTE
For off road use only
add to unleaded gas
replaces lead protection
reduces exhaust emmissions.


i don't know if this stuff works or not. i was born post leaded gas age, and all i've ever heard is that lead is not good for the earth, but i also hear it gives you better performance. i have a stock 81 corvette with the cat. i don't know if that makes any difference, and a 74 chevy k-10 that has edelbrock carb and intake, and lifters with no cat. my question is, will it really give me any performance gains, and will it clean the motor? it also claims it prevents metal-to-metal contact. is this true?
any information on this stuff would be great
thanks in advance
Casey

It's my understanding that lead in gas provided two benefits. One was that it raised the octane number and allowed higher compression ratios (more power) without detonation and the other was that it provided lubrication for the exhaust valve seats. When unleaded gas came on the scene, engines came with hardened exhaust valve seats and lower compression ratios and no longer required the lead. About all I know that adding a lead additive or substitute to an engine that was set up to run on unleaded would do is allow more advance in ignition timing which could result in more power. But that depends on a lot of things.

Marc

Lead was always a cheap valve lubricant and octane enhancer in gasoline. It's a deadly enemy of a catalytic converter besides a cause of pollution, both of which led to it's demise in gasoline.

The substitute lead additives act as a valve lubricant in engines designed for leaded gas. Any engine made for unleaded gas since the early to mid '70s have hardened valve seats so the lead isn't required. Any older engines that have been rebuilt should have had hardened valve seats installed so they can run on the current unleaded stuff.

Using the additives according to directions won't hurt anything, at least they say so. It's for the older engines and has no real benefit for newer ones.

Try a can or two...if you notice a difference, keep using it. If not, you've only wasted a couple of bucks.

That brings back memories of my gas-pumping days when someone asked for $5 regular, I had to ask "regular regular, or regular unleaded?"



I always thought that lead was extracted from petroleum,, not added to

5$ regular?? Wow... I remember the days when 5$ of regular might actually get you somewhere. Nowadays I think I spend 5$ every time I turn the key!!! ESPECIALLY out here in California.

All of the above is true. If your car is older than early 70, there is no reason to add lead. Lead will kill a catalytic converter. If your car needs it any you didn't add it, you have probably already done a valve job, had new guides and hardened seats installed, and now don't need it anymore. Yes it is VERY bad for the environment. It affects you brain and nervous system, and makes you stupid. As for the octane boost, you can get octane booster without the lead, or just by highter octane fuel. Your car may run better or worse with highter octane fuel.

Here I go.
Most people thing high octane fuel is a hotter fuel. Not So. Octane is a resistance to burning. The highter the octane, the colder and slower the fuel burns. The reason it can provide more power is the fact that it burns for a longer period of time.
Common thought is the explosiong of fuel pushed the piston down. Wrong. First, fuel should not explode in the cylinder. If it does you have knocking and pinging, and preignition, all of which can damage the engine and cause driveability problems. Correct ignition provides a controlled burn inside the cylinder.

Now to make a comparison. Temperature and heat are two different things. Temperature is a measure of intensity, measured in degrees. Heat is a measure of volume, measured in BTUs (Brittish Thermal Units) One BTU is the amount of heat required to raise one pound of water 1 degree F. To compare the two, look at a furnace and cutting torch. The furnace will usually top out about 140 deg F. It can heat your house, but won't cut steel. The cutting torch reaches 9000 deg F. It will cut through steel, but won't heat even one room of your home.

By burning longer, higher octane fuel creates more total heat. You can VERY quickly pass your hand through a torch flame without harm. But if you hold you hand over a lighter for an extended period it will give you a severe burn. Much less temp, but more total BTU over time. And yes, the temp of your hand will get higher due to the increased BTU transferred into your hand.

Now what happens in the cylinder? Air and fuel is pulled in. Compression takes place, and the mixture is lit by the spark plug. Some pressure is placed on the pistion due to the force of the burn, but that is not the primary force applied to the piston. At about 10 to 20 degrees after top dead center, the flame is out. The fuel and oxygen is consumed. But there is still all of the air in the cylinder. About 70 percent of what was in the cylinder was inert atmosphere gasses. Mostly Nitrogen. This air was super heated by the combustion. Heat causes things to expand. The super heated air tries to expands, and creates a LOT of pressure. This is what pushes the piston down and creates power at the crankshaft.

High octane fuel heats the air for a longer period of time, although at a lower burn temp, it imparts more BTU into the air, and causes greater expansion, and more force on the piston.

Some cars will run better with high octane, some worse. If the fuel burns too cool (high octane) it may not be a hot enough burn to completely burn the fuel, thus making less BTUs, and less power. Regular fuel (low octane) may produce enough temp create a complete burn and more BTUs. This is dependent on how the engine is built. Compression, valve timing, ignition timing, manifolds, etc. ( the list is huge if I go into detail )
A car may run well on high octane once warmed up, but could start hard and run poor cold. Low octane may cure starting and warm up problems, but provide less power.
In some cases low octane produces more power. Fuel mileage is another factor that could be affected by either one.
How do you choose. Try both and make a compare. What gives YOUR car better mileage and more power? This can even vary between different brands of the same octane.

There are three ways of measuring octane. Most fuels at pumps now are a blend of the first two. You will see R+M divided by 2 when you look for octane ratings on modern pumps. We have actually used that for a long enough time, some pumps have quit posting the formula. The Feds now require the blended rating. When looking at spec books from years ago, they may have used either method. VW used to require 91 octane, which was regular, not high test. Be careful of this when looking at older spec.


I used to buy a full tank, 20 gallons, and have enough change from a $5.00 to by lunch at McDonalds. All with my 64 Comet. When fuel topped .20 per gallon I thought it was getting high. When it hit 41.9 cents I thought Sohio was on cheap drugs, no one would pay that, not even for the high test Boron. Oh well, I was young. That was 1972.


If you guys and gals get tired of my long winded explanations let me know. If you like them let me know that as well.

Ken Styer

Ken, It's been awhile since my chem. days, but I believe a btu is the amount of heat required to raise a cc of water 1 degree, not a gallon. Regards Phil Anderson

Ken, thanks a lot. u really explained a lot. im going to try different octanes, and see how they affect mileage and power on my cars. what were u saying about...


"There are three ways of measuring octane. MOST FUELS AT PUMPS NOW ARE A BLEND OF THE FIRST TWO. You will see R+M divided by 2 when you look for octane ratings on modern pumps."
what exactly are u saying? sorry for the confusion, but i like ur detailed explanations.
thanks

Phil take another look at my post. I said a pound of water, not a gallon. I double checked my formula. One BTU to raise one pound of water in one degree F. I don't remember how many pounds of water in a gallon, somewhere between 7 and 12 perhaps?


The octane methods are the Research Octane Number (RON) and the Motor Octane Number (MON). These are the first two ways of calculating octane. A RON number of 98 would be about equal to a MON of 90.
The formula the Feds now require posted on pumps is a blend of the two formulas.
(R+M)/2
RON number plus MON number divided by 2
In the above example the octane number would be 94.
When you see a number posted it is now the (R+M)/2 rating.

Ken Styer

|UPDATED|2/22/2004 6:03:37 PM (AZT)|/UPDATED|

Water is 8 pounds per gallon. Fuel is about 6.7 pounds per gallon... . .  .