Exhaust on my z

I do plan on doing an exhaust upgrade for my future 69 mustang. But it will be a real exhaust upgrade, not just a shitty muffler.
 
Future upgrades for future cars? Well, since we're on the subject, I plan on putting a supercharger on my future Lambo.
 
A 69 mustang isn't as expensive as a lambo. ;) And I already know of a seller who is willing to sell me theirs once I get out of basic. 3k, no rust, 302 and transmission that barley runs. Pretty solid paint, decent interior.

I was planning on having the engine and transmission rebuilt anyways.
 
Geck0 said:
Some fuckwit was rabbiting on at me the other day about how I need to get a catback 3" single on my Soarer. It has a dual catback 2.5" system and it's a 2.5L TT. He couldn't get the whole 2 x 2.5 = 5 thing.

People are fuckwits anyway, the number of Skyline GTS-T owners I see spending up big on turbo back systems with the standard turbo and losing their backpressure makes me piss myself laughing.

My brother is one of them. "AW Fuck! Where'd all my bottom end go!?!?!" :lol:
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Losing power-robbing backpressure is most of the point behind getting a larger exhaust system. On turbo cars this is doubly important. The bigger the better, plain and simple.

Why the hell do you want backpressure?
 
Project2501 said:
Sounds good to me, but I think any type of "dual exhaust" on anything other than an 8 cylinder is fucking retarded (and only adds weight, no performance).

And for fuck sakes, get that smoke checked out. Definitely burning fuel or somethin. yeesh.
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Why the fuck does it matter if its a V6 or a V8? Why do 8 cylinders lend themselves to dual pipes any more than 6?

Retarded.
 
rofl

you guys call it a rice, even though it is an asian vehicle, gg

car does sound like poopsex though

also, dual exaughst could improve performance, and my mazda 6 has dual exaughst and it crosses in the middle to balance out the cylinders for a better push

INCOMING FIRE!
 
personally i'm not a fan of the coffee can exhaust sound. i prefer the sound of my z with the standard muffler, it's bassy enough for now. i hope you changed it cuz you wanted to not cuz you thought you needed a higher flow exhaust.
 
amRam said:
Losing power-robbing backpressure is most of the point behind getting a larger exhaust system. On turbo cars this is doubly important. The bigger the better, plain and simple.

Why the hell do you want backpressure?
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Torque on the low end, depends on what you're using the vehicle for.

A muffler is an ambiguity in the performance world, as it can have both good and bad effects on power output. Back pressure is essential for peak power in almost any application, even 6000hp alcohol-burning Top Fuel dragsters have some built-in back pressure. Before we begin this discussion, take note that 1 atmosphere is the pressure that air is at naturally (uncontained) at sea level.

During the combustion process, when the exhaust valve is open, all of the compressed (and depeleted) air-fuel mixture spills out from the cylinders as fast as it can, through your exhaust manifold, into your catalytic converter(s), the muffler, and finally out the tail pipe. The problem with this is, just before your exhaust valve is about to close again, your intake valve opens up, allowing the fresh air-fuel mixture to rush into the cylinders. This is called overlap, and one of the things you take into consideration when choosing a cam, because it can be used to your advantage.

If there was no valve overlap, it would be 100% impossible to completely irradicate all of the spent gases from the cylinder. This has a two-fold effect on power output, depending on what RPM the motor is running at. At low RPM, this effect actually increases torque, because the least amount of compression is lost during the intake stroke, and the ratio of intake to exhaust gases is high. Unfortunately, as the RPMs increase, there is increasingly less time to evacuate the exhaust gases during the exhaust stroke, and more and more depleted air-fuel remains in the cylinders when the exhaust valve closes. The motor becomes incredibly inefficient near its readline. A motor designed for high-torque applications, such as towing, tends to exhibit less valve overlap then normal. The type of cam used in this application is often called an "RV" cam, because a recreational vehicle doesn't need horsepower as much as it needs low-end torque to get it moving.
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-cyanide- said:
i have flowmasters on my car
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i have flowmasters on my truck

im not a real gear head or anything, but I always assumed from just commonly seeing this on the road and on tv shows that flowmasters are more geared towards trucks and magnaflo towards cars?
 
GreyGhost said:
Torque on the low end, depends on what you're using the vehicle for.
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Uh not so much...

An engine is a glorified air pump. If you put a restriction (backpressure) on one end, you're making the engine work harder and waste more energy on pushing that exhaust out to clear the way for incoming air.

Backpressure is bad. That article really seems retarded. The guy is using top fuel dragsters as a fucking example? he must not realize they run open headers... yeah, lots of backpressure there. :rolleyes:

Also, the guy who wrote the article obviously doesn't know the difference between scavenging and backpressure. Valve overlap is effective with scavenging because the escaping gases create a vacuum and help suck the fuel/air mixture while both valves are open... unfortunately, the way to increase scavenging is to decrease exhaust volume in order to increase exhaust velocity. The negative effect is backpressure.

Again, backpressure is bad.
 
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Again, not always.

The internal combustion engine is a complex, dynamic collection of different systems working together to convert the stored power in gasoline into mechanical energy to push a car down the road. Anytime one of these systems are modified, that mod will also indirectly affect the other systems, as well.

Now, valve burning occurs as a result of a very lean-burning engine. In order to achieve a theoretical optimal combustion, an engine needs 14.7 parts of oxygen by mass to 1 part of gasoline (again, by mass). This is referred to as a stochiometric (chemically correct) mixture, and is commonly referred to as a 14.7:1 mix. If an engine burns with less oxygen present (13:1, 12:1, etc...), it is said to run rich. Conversely, if the engine runs with more oxygen present (16:1, 17:1, etc...), it is said to run lean. Today's engines are designed to run at 14.7:1 for normally cruising, with rich mixtures on acceleration or warm-up, and lean mixtures while decelerating.

Getting back to the discussion, the reason that exhaust valves burn is because the engine is burning lean. Normal engines will tolerate lean burning for a little bit, but not for sustained periods of time. The reason why the engine is burning lean to begin with is that the reduction in backpressure is causing more air to be drawn into the combustion chamber than before. Earlier cars (and motorcycles) with carburetion often could not adjust because of the way that backpressure caused air to flow backwards through the carburetor after the air already got loaded down with fuel, and caused the air to receive a second load of fuel. While a bad design, it was nonetheless used in a lot of vehicles. Once these vehicles received performance mods that reduced backpressure, they no longer had that double-loading effect, and then tended to burn valves because of the resulting over-lean condition. This, incidentally, also provides a basis for the "torque increase" seen if backpressure is maintained. As the fuel/air mixture becomes leaner, the resultant combustion will produce progressively less and less of the force needed to produce torque.
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