Thread: Mustang on Leaded Fuel...>help

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i got a modified 5.0 that i drive around as a daily driver....once in a while when i do street races i put a little bit of leaded fuel in the taank for i little more power.....i can notice the power right away..

i
s this a good idea or not,,,,its fuel injected so that problem is out of the way.... im trying to figure out if this will cause any longtime problems for my car...

If you have catalytic converters and need to pass smog checks, you could have a problem. The unleaded fuel will destroy the inards and you will need to replace them.

Pat

Where ya getting leaded gas ? far as I know it is not available,not even in racing fuel......lead in gasoline was banned by the U.S Government Jan.1,1996

If you really want to get a boost try adding liquid oxygen. It's easier to find than leaded gas.

Originally posted by The Al Show
If you really want to get a boost try adding liquid oxygen. It's easier to find than leaded gas.

Originally posted by The Al Show
If you really want to get a boost try adding liquid oxygen. It's easier to find than leaded gas.

LOX ............... works best in da' JATO rocket. Or an acceptable alternative would be a platinum block.

100 Unleaded is available in every major market in the US. Lead does nothing for performance, and was only used as valve lubrication. Octane is a number to compare for detonation purposes and if the computer bases the timing on a knock sensor, you find that power from 100 octane than from 92. If the injection system limits the amount of ignition advance, the octane amount won't matter.

first i got a dynomaxx cat back system with headers...thats just the exhaust mods.....and i can get leaded race gas at the pump in elkhart lake by Road America in wisconsin....(the kart racing track) i can get it at the pump at the gas station off of hwy j.....
its power 110 leaded race gas....i put that in my race quad...
and in my count ther are no smog checks.....no emmision tests....and the cops are very lienient about the exhaust noise so that aint a problem for me

Originally posted by Mustang5.O
........ i put a little bit of leaded fuel in the taank for i little more power.....i can notice the power right away..

Ahhhh...........mythology vs reality! This thread is loaded with it. Not to poke fun at anyone, I realize sometimes we write stuff that doesn't exactly come out the way we intend.

Using higher octane fuel (deal with lead later) won't change power output in your engine unless something in the engine changes to increase it's efficiency. There's nothign magic and powerful in that octane stuff, whereever that comes from (it's actually a reference chemical used as a standard to measure against). Internal combustion engines only utilize a fraction of the available energy in a unit of fuel, say 35-40%. Higher static compression is one way to increase that efficiency. And that's what higher octane fuels were designed to allow. Of course, a load of fuel in your tank won't do that. In theory, a "smart" computer control module could change timing (dynamic compression ratio) and extract some greater level of efficiency, but we're talking small percentages here. From what I've read the ccm in a '90 Mustang doesn't do that, but I don't have personal experience with that. If you're feeling any "power right away" it's probably due to your wallet being lighter and your brain needing some gratification. In some circles that's called stroking the dog to feed the cat (familized version).

Now the lead thing. (abreviated version, I'm short on time this morning) These myths just don't want to go away, I guess because folklore is so comforting. The ONLY reason tetraethyl lead was introduced into gasoline was that it was the most economical chemical compound that contributed to higher octane ratings of fuel. All the BS about lubrication is just that..........BS. In fact, when all the science guys were searching for the "magic potion" to increase octane rating during the early part of the twentieth century, tetraethyl lead wasn't their first choice. As often happens there was significant difference of opinion in the community. Lead, even then was know to be hazardous (though not hysterically so). And it contributed to significant depositing in the engine and exhaust system. Since it was so inexpensive it won out anyway. The science guys figured out a way to put another additive in the additive to help keep deposits to a minimum. They're called scavengers, because they scavenge the unwanted deposits out of the combustion chamber. The main reason for bringing this up is that this whold fairy tale thing about the magic lubrication qualities of lead is bunk. The formulators of gasoline did as much as they could to get that stuff out of the engine. Since they weren't 100% successful, there were some deposits left behind. Those deposits, consider them contaminants, dirtied the exhaust valve seat and face which kept the two hot surfaces from "welding" together. It's that welding and subsequent tearing that caused exhaust valves and seats to errode. Dirty surfaces don't weld well, that's all lead contributed. I suppose if you're really stubborn you could twist that into a lubrication scenario of you wanted to. Note too that lead oxide(the result of the burned lead compound) doesn't have any contact with a correctly functioning intake valve.

In order to get the lead out two primary chemical compounds were used. Ethylene dibromide or ehtylene dichromide. The kept most of the lead in a gaseous state for a while so that the exhaust flow would carry it away. Of course these halogenated compounds became corrosive in the presence of water...........which the combustion process is loaded with. Wonder why spark plugs and exhaust systems last longer now a days (probably a question more meaningful to geezers). Sure there's an element of better materials (platinum plugs and aluminized or stainless exhaust) but it's also due to less corrosive elements in the combustion/exhaust stream because of the abscense of those lead scavengers.

One other minor nit, higher octane fuel has little to nothing to do with preignition. Higher octane fuels deal with controling the rate of fuel ignition AFTER the spark plug fires. Preignition, by it's definition, is prior to the spark plug firing.

Uncle Bob:
Should I waste my money running high(!?) octane in my V8-60?. It has Offenhauser 10:1 heads, probably 9.5:1 with the relieved block, and a nasty-azz Clay Smith cam. Back in the day, I probably ran regular; but back in the day, regular was probably 92-94 octane. It's hard to hear a flattie pinging, especially in an open roadster, and I wouldn't want to melt anything expensive.

Bob's information is correct. When they were looking for an additive in the early 20's, the reason was to increase compression in engines. They had no "lubrication" intent. Most of the myth stuff alludes to the depositiion of lead "to prevent wear"......reason would suggest that lead is soft and would not wear well (engine bearings are not contact wear items).

Here is a link with some history:

http://www.chm.bris.ac.uk/motm/leadtet/leadh.htm

You arent going to pull up to a pump in the USA and get leaded gas out of a hose.....no matter where you live. Federal Law took care of that years ago. Maybe out of a 55 gal drum but not the pump.

yup, instead of using leaded gas or any nonsense, if you're looking for high octane for racing and run enough compression to make it worthwhile... pay the money and get trick fuel.... even if its $7 a gallon... i used to have a VW bug with so much crap done to it that we took it to a small private airport and fueled it up with 167 octane aircraft fuel, that stuff was potent, but it was required when you're putting out 400+ hp out of a tiny little 4cyl motor.. too bad someone stole that car, it could keep up with the 9sec cars

Denny,
The first of your links in response to my post demonstrates that even a PHD can be guilty of passing on inaccurate information when the subject matter is outside of his area of interest. His organization's primary objective is in the area of pollution, not automotive mechanics. The second one from Australia about Rolls Royce however is very well written. The only major item of conflict there is a function of the U.S. way of doing things vs the European model. We actually measure octane rating three ways; RON, MON, and then whats posted on the pump, each of which come up with a different number for the same fuel sample.

The real issue with low octane rated fuels is detonation (autoignition). Here's a link to a well defined difference between the two. http://www.misterfixit.com/deton.htm
As I said, it was a small nit. Preignition can in fact lead to detonation, and the causes of each can overlap. It is very possible to have both in the same engine, but they are separate functions.

60nut. Octane requirement is an empirical thing. 10 to 1 on a flathead seems high, even 9.5 considering the relieving, but let's say you're right. Think of octane requirement as a heat resultant thing. The higher the heat in the combustion chamber, the higher the octane requirment. Your aluminum heads help keep the temp lower, the exhaust routing on a flathead keeps it higher. Combustion chamber deposits increase temp. A poor cooling system (or corrosion loaded block) increases temp. The article in the link above denotes a number of other contributors. In other words, damned if I know what your needs are. It may be that you can get by on regular grade, especially in a light weight car like a T bucket, and if you don't ever put a big load on it (e.g. racing, towing, etc.) If you drive in high ambient temps that will increase the octane need, so your requirement could be different seasonally. And as you said, it's hard to hear it ping in an open roadster. And if you're like me, your hearing has deteriorated to a point where you may not be able to hear it anyway. If it were mine, I'd buy the higher grade just for insurance sake, even though it may not be providing any additional benefit. If you're obsessive about it, find a tune shop that can attach a knock sensor and can simulate your highest operating temp situation and test for detonation.

Originally posted by DennyW
Yes Bob, ............. So, what's your point?

Just a silly notion that proper use of teminology matters.

Fuel of adequate octane rating will control detonation, but preignition can still occur despite that correct octane rated fuel.

Originally posted by Bob Parmenter
Just a silly notion that proper use of teminology matters.

Fuel of adequate octane rating will control detonation, but preignition can still occur despite that correct octane rated fuel.

looks like to me there has been something missing from this thread and that is the dif. in octane ratings. you're talking 93 now and in the 70s hay day it was what 97 plus. until you get the same octane fuel in the motor, its no way to compare anything. you could build a faster motor on pump gas in the 70s than you can now. with the EFI its about evened it self out, but as far as the lubrication part goes until i see some proof ill stick with what ive been told all my life.its been at least a 1/2 dozen threads on replacing the valve seats in the older heads to harder ones because there was no lubrication in un lead fuels like it was in the leaded fuels, on this forum in the last mo. and this is the first time ive heard anything about no lubrication being in leaded fuel. you went way over my head on most of your post bob but i think im reading it right. if not let me know.