Discussion in 'Fox 5.0 Mustang Tech' started by slvr302, Aug 15, 2003.
victor needs a drink and a snickers bar to collect his thoughts.
I understand what you are saying, that's why i posted about how he is. he's a cool guy when you get to know him, but he rubs some people the wrong way. I told you up front because if you decided to go there, and you didn't like something, i pretty much put up a disclaimer about his personal skills. and it would not be my fault
And you're right it is my opinion that he is the best, and an opinion is all that it is.
Oh and he knows and likes the guys from Crazy Horse, that's why i said not to bad mouth them.
Hey, if it's still messed up in the winter, give him a try, he'll fix it. Especially when race season is not going on.
Actually blowing 1-2 pounds of air into the exhaust before the Catalytic Converter COOLS THEM. When you add outside air to the exhaust which is 300-400 degrees COOLER, its going to drop your exhaust temperatures down to a level where it doesn't melt your converters.
If you run without a smog pump with cats, you run a great risk of melting the converters. As a result, they will get plugged, not flow and have tons of back pressure.
If your converters have already begun to Melt (Which I suspect they have) then added the extra air to the backpressure that you are experiencing will even further make your converters a blow torch.
Got any idea how a blast furnace works? If not try this next time you fire up the grill: once the charcoal gets going real good, grab an electric fan and blow it on the coals. Even though you're blowing air that is WAY cooler than the coals, it sure as hell doesn't cool them off, does it? Air is 21% oxygen. Force it into a fire, or hot cats, the fire gets hotter. You have to remove the fuel before forced air can cool.
Blowing air downstream to the coverters is not to cool them regardless that the outside air is cooler. The reason for air to be forced downstream to the converters is to help with the conversion process (to clean up emissions). Numerous people in these forums continue to post what you have stated above with regards to the smog pump. There are plenty of persons that will tell you that they run converters and no smog pump and haven't had a "meltdown" issue. There experince is not the basis for statement, rather just an example.
Please explain how added air to my converters will turn them into "a blow torch" without alot of unburnt fuel being present to allow that to happen? Let's say the converters are partially clogged which I agree with. Blowing air to them will not make them glow more (get hotter). It's the presence of unburnt fuel and now more air intoduced by the smog pump that allows the converters to glow even more than before. Like Sarge has mentioned.
Yes I do actually. A blast Furnace has no back pressure above the fuel source. The heat generated is due to the focus of the fuel and the ignition point. That is the hottest part of the blast furnace.
Now lets take the combustion engine. The hotest place of the internal combustion engine is in the cylinders or 2-3 inches outside the exhaust ports. Once the exhaust gases travel 18" they lose a incrediable amount of heat. Now if you mix cooler air into the stream at this point, the exhaust temperatures cool even futher. You know sort of the same thing as Military Aircraft (Which is apparent that you dont know of this technology). If you mix cooler air into the exhaust stream of a fighter jet, (Just like the smog pump does on a automobile), it cools the exhaust a lot.
Your reference of a blast furnace doesn't apply in this case, because as the exhaust (Spent fuel) travels down, it doesn't heat up any futher.
The only way your exhaust can heat up is if you have a obstruction. Like catalytic converters which are melting on the inside. THis backpressure will cause more friction and more heat due to the fact that you are COMPRESSING the gas.
Having a smog pump on a automobiles exhaust COOLS it and also helps the catalytic converters work. If a car's Exhaust gases are too hot, then it will FAIL emission standards. Today some car manufacturers put their catalytic converters so far down the exhaust track that there is no need for a smog pump to cool the exhaust before it enters the primiary catalytic converters. However on the 5.0L Mustang the Smog pump actually cools the exhaust so that you do not melt the converters and adding air helps maintain the emissions standards.
4.6s have eliminated the smog pump and the converters on these cars have no provision for any secondary air injection. Are these cats subject to overheating right from the factory because of this?
No they are designed differently. The Emissions system of the 4.6L Cars are Different than the 5.0L cars.
Are you saying that the 4.6s have secondary air injection just like the 5.0L?
I'm sure the emissions system is most likely designed a little differently but both systems share common functions.
1. Air/fuel ratio has to be controlled or monitored.
2. Catalytic converters have to be used to reduce emissions.
Those two factors are the key. So what is so different that can be achieved with the 4.6 that cant be done on the 5.0? How are the 4.6 converters "cooled"?
don't the 4.6 cars have 2 preheaters and 4 cats as opposed to the 5.0's 2 preheaters and 2 cats, stock speaking of coarse. Also whats the point of the mil elminators on the 4.6's when u remove the smog equipment
MIL eliminators is so you dont throw the check engine light I thought. If I remember correctly, my buddy's 99 cobra has an aftermarket Bassani catted x-pipe with no provisions for secondary air injection. I am not sure how the exhaust setup comes from factory. I am almost positive they don't have a smog pump.
The blast furnace analogy was a generalization for the benefit those not so technically inclined. Lighten up, professor.
True, but your assuming no raw fuel downstream. He described burning of the eyes and nose, indicating a fair amount of raw fuel in the exhaust. The raw fuel laden gasses are obstructed by the cats. The extra air causes the unburned fuel to burn (the hot cats are the source of ignition). Think of an afterburner, if this is over your head. Extra fuel + extra oxygen = extra heat. Simple physics.
Again, you've forgotten about unburned fuel.
Catalytic converters are designed to run hot enough to burn any unburned fuel in the exhaust gasses. They can't do that if they're cool. Hot exhaust gasses are generally cleaner, because of the abscence of raw fuel.
yeah i think when u swap to an offroad pipe right? the mil kills the check engine light
I skimmed throuhg all the posts in here, and I don't think I saw this mentioned, so I'll throw it out here:
If you got the cats really hot, you might have just melted them. If the car is at a point now where it runs fine without the cats and when you put them on it doesn't -- try a different set.
The car always ran fine.The tune now and before have supposedly been fine. Just the fumes out the exhaust were hurrendous. Larocca has tried a stock h-pipe and they too got extremely hot thus eliminating the converter as the problem.
Actually Catalytic converters are NOT designed to burn ANY unburned fuel. They are designed to force a chemical reaction to change certain gases in the exhaust into water by a forced reaction, there by reducing the hydrocarbons in the exhaust. However there is a narrow temperature range that this can occure in. If you exceed that temperature range, then you will MELT your converters.
FACT Raw fuel that enters a catalytic converters will DESTROY THEM. Catalytic converters are NOT Designed to have raw fuel going through them.
Sarge Just got
The advent of Catalyic converters in the 70's and used to the late to mid 90's were designed to have air pumped into them before the converters to cool the exhaust to keep the converters in a narrow heat range that they need to operate. Modern converters are made with different materials and designs that allow them to operate at a higher temperature, therefore MOST new cars of today do not even have a smog pump on them anymore.
Excessive raw fuel will burn them up. That's his problem,Sherlock.
Whatever helps you sleep at night.
The advent of Catalyic converters in the 70's and used to the late to mid 90's were designed to have air pumped into them before the converters to cool the exhaust to keep the converters in a narrow heat range that they need to operate. Modern converters are made with different materials and designs that allow them to operate at a higher temperature, therefore MOST new cars of today do not even have a smog pump on them anymore.[/QUOTE]
From www.about.com.concerning smog pumps......"Definition: A slang term for an air injection system pump. Used to pump extra air into the exhaust system to help the converter reburn pollutants."
Forced88lx... check this out. http://auto.howstuffworks.com/catalytic-converter2.htm You are not quite right about all that... Sarge is actually more accurate in what he is saying. You are wrong about there not being "raw" fuel in the exhaust... whatever raw means... It is unburned... I consider that raw.
Anyway... I would say try another Cat H-pipe... eventhough the stocker you tried also got hot. Doesn't mean anything. Parts go bad, and new parts too.
Why is it you are not running O2 sensors, but you are running cats?
I agree with trying another catted H-pipe
SARGE GO READ WHAT YOU POSTED YOU SAID CATALYTIC CONVERTERS BURN FUEL WHICH IS WRONG if you allow fuel to get into it, guess what you just burned them up. Quit being a hypocrite.
The above QUOTE is what you Sarge Said which is WRONG.