Close but no cigar 😉
The exhaust gasses leaving the cylinder are traveling faster than the speed of sound, creating sonic booms.
The exhaust gasses leaving the cylinder are traveling faster than the speed of sound, creating sonic booms.
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Car Enthusiasts....Exhaust Question
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Angrymarshmello
Lifer
Cool, didn't know that. (Stupid physics teacher didn't know what he was talking about apparently) 🙂
desertdweller
Senior member
I've hot rodded three Mustangs; a '82 GT, a '85 LX, and my last one was a '68 coupe.
I think the Flowmaster exhaust in a Mustang sound the best, especially the three
chambered mufflers. I personally don't like Borla exhaust on Mustangs, it just makes
them sound funny. With a Mustang you kinda expect to hear a certain tone from it
and Borla just doesn't do it.
I don't know anything about the Steeda mufflers.
Another you might consider checking out is the Edelbrock mufflers, I've been told they
flow better than the Flowmasters, but I've never actually heard what they sound like.
DD
teckmaster
Golden Member
I would see if Roush performance makes an exhaust for it
When the exhaust valve opens, the air fuel mixture is still burning (This is why you see flames coming out of open headers), these gasses exit the cylinder head extremely fast.
The average combustion pressure inside a gasoline engine aproachs 5,000 psi of pressure at the moment of ignition under full load and throttle.
As the exhaust valve opens, this pressure which has been reduced to below 1,000 psi is forced out of the cylinder by the residual pressure and the piston coming up the cylinder bore.
If you remove the exhaust manifolds/headers off your vehicle and let it idle, you will hear some noise, but it is not going to be extremely loud, now rev the engine up and the noise will become unbearable, why ?
At low speed, very little fuel is being burned to keep the engine idling, this effectively reduces the gas pressures and speed below the thresh hold for sonic booms, as the accelrator is depressed, more fuel and air enter the engine raising the pressures and speed of the exhaust gasses past the point of the speed of sound.
Exhaust gasses can reach 350 FPS 😉
Here's another good tech question;
At what temperature does gasoline burn inside the combustion chamber ?
The average combustion pressure inside a gasoline engine aproachs 5,000 psi of pressure at the moment of ignition under full load and throttle.
As the exhaust valve opens, this pressure which has been reduced to below 1,000 psi is forced out of the cylinder by the residual pressure and the piston coming up the cylinder bore.
If you remove the exhaust manifolds/headers off your vehicle and let it idle, you will hear some noise, but it is not going to be extremely loud, now rev the engine up and the noise will become unbearable, why ?
At low speed, very little fuel is being burned to keep the engine idling, this effectively reduces the gas pressures and speed below the thresh hold for sonic booms, as the accelrator is depressed, more fuel and air enter the engine raising the pressures and speed of the exhaust gasses past the point of the speed of sound.
Exhaust gasses can reach 350 FPS 😉
Here's another good tech question;
At what temperature does gasoline burn inside the combustion chamber ?
Exhausts are for wussies! Get a cutout 😉
j/k
I would look at the Steeda... they make a lot of great stuff for Mustangs and quality is quite good.
Also, another option to look at might be a Dynomax they make catbacks for the Cobra as well they're cheap is all I can say. Not sure if they have stainless or not. I'd go with the Flowmaster catback before the Dynomax anywho, especially with a Delta series muffler.
j/k
I would look at the Steeda... they make a lot of great stuff for Mustangs and quality is quite good.
Also, another option to look at might be a Dynomax they make catbacks for the Cobra as well they're cheap is all I can say. Not sure if they have stainless or not. I'd go with the Flowmaster catback before the Dynomax anywho, especially with a Delta series muffler.
FrustratedUser
Lifer
I've got a question for Roger.
Why is 2 stroke engines always more noisy than 4 strokes?
Answer in a little while....
Why is 2 stroke engines always more noisy than 4 strokes?
Answer in a little while....
First off, they are not 😉
4 stroke = Pistons travels up and down it's bore 4 times for every power stroke.
2 stroke = Pistons travel up and down it's bore 2 times for every power stroke.
For a 4 stroke, the crankshaft rotates twice for evry power stroke.
For a two stroke, the crankshaft rotates once for every power stroke.(Twice the number of exhaust pulses)<---- Your answer 😉
On a side note, the exhaust gasses on a two stroke exit the cylinder through a port bored into the side of the bore resulting in a more exposed flame front to the atmosphere.
Another good reason why they could be noisier, most two strokes are aircooled, aircooled engines are noisier because the cylinders are exposed directly to the atmoshere.
Water cooled engines have water jackets surrounding the cylinders effectively dampening the noise.
4 stroke = Pistons travels up and down it's bore 4 times for every power stroke.
2 stroke = Pistons travel up and down it's bore 2 times for every power stroke.
For a 4 stroke, the crankshaft rotates twice for evry power stroke.
For a two stroke, the crankshaft rotates once for every power stroke.(Twice the number of exhaust pulses)<---- Your answer 😉
On a side note, the exhaust gasses on a two stroke exit the cylinder through a port bored into the side of the bore resulting in a more exposed flame front to the atmosphere.
Another good reason why they could be noisier, most two strokes are aircooled, aircooled engines are noisier because the cylinders are exposed directly to the atmoshere.
Water cooled engines have water jackets surrounding the cylinders effectively dampening the noise.
The Cobra already has headers from the factory 😉
FrustratedUser
Lifer
Well, they are more noisy. Always.
The reason is that the exhaust port of a 2-stroke engine opens while the gas is still burning so you hear both the supersonic soundwave and the combustion (explosion) itself. In a 4 stroke most of the fuel is burnt away when the exhaust opens.
When I say that they are always more noisy I mean that the design is more noisy. Ofcourse you can add extra noise reduction, water cooling and what not.
I meant the basic design itself.
Gasoline does not explode inside the combustion chamber, it burns rapidly 😉
FrustratedUser
Lifer
I think you know what I mean. 😉
Besides that, the pressure inside the cylinder when the exhaust ports open in a 2 stroke is (generally) higher than when the exhaust valves open in a 4 stroke.
🙂
Anyone care to answer the question "At what temperature does gasoline burn inside the combustion chamber" ?
Anyone care to answer the question "At what temperature does gasoline burn inside the combustion chamber" ?
cavemanmoron
Lifer
i have Flowmaster American Thunder on my '67 Camaro big block 427
sounds great, on the car 3 years now, no rust, the system is like alun=minized, silver color new, i was under the car in October,looking at the exhaust closley,for a minor exhaust leak,,:|
all the pipes,and mufflers are great,
i need to replace the gasket at the header reducer,LOL
17248 kit if i remember right for your car
FLO-17248 Ford: 1999-2000 4.6L DOHC Mustang Cobra, 2 1/2 in. dual rear exit, stainless steel tailpipes, American Thunder... $339.95
here at summitracing
oh yeah they sound Great!
sounds great, on the car 3 years now, no rust, the system is like alun=minized, silver color new, i was under the car in October,looking at the exhaust closley,for a minor exhaust leak,,:|
all the pipes,and mufflers are great,
i need to replace the gasket at the header reducer,LOL
17248 kit if i remember right for your car
FLO-17248 Ford: 1999-2000 4.6L DOHC Mustang Cobra, 2 1/2 in. dual rear exit, stainless steel tailpipes, American Thunder... $339.95
here at summitracing
oh yeah they sound Great!
No, that is nuclear fission/fusion, not combustion.
cavemanmoron
Lifer
look here,
1999-2001 Ford Mustang GT
4.6L Engines
Part# 17312
American Thunder? System
Dual 2.50" System with 3.00" Polished Stainless Tips
Flowmaster now offers a new exhaust system for the 1999-01 Ford Mustang GT's equipped with the 4.6L engine option. This new American Thunder system features an improved design for added performance and torque while offering 3.00" polished stainless tips for a clean, yet aggressive appearance.
Product Features:
- Fully Aluminized Steel Construction for product durability.
- Designed for 4.6L-equipped vehicles.
- Complete bolt-on cat-back 2.50" style dual exhaust system with 3.00" polished stainless tips.
- Specially designed 5x10 40-Series? mufflers for a deep aggressive exterior tone, yet maintains reduced interior resonance.
- Computer controlled mandrel bent tubing for maximum exhaust flow and lower restriction.
Product Benefits:
- Aluminized steel for extended product life.
- Reduced backpressure for maximum exhaust flow.
- Stock factory style hangers for easy installation.
- 50 state emissions legal.
- 100 % American made.
1999-2001 Ford Mustang GT
4.6L Engines
Part# 17312
American Thunder? System
Dual 2.50" System with 3.00" Polished Stainless Tips
Flowmaster now offers a new exhaust system for the 1999-01 Ford Mustang GT's equipped with the 4.6L engine option. This new American Thunder system features an improved design for added performance and torque while offering 3.00" polished stainless tips for a clean, yet aggressive appearance.
Product Features:
- Fully Aluminized Steel Construction for product durability.
- Designed for 4.6L-equipped vehicles.
- Complete bolt-on cat-back 2.50" style dual exhaust system with 3.00" polished stainless tips.
- Specially designed 5x10 40-Series? mufflers for a deep aggressive exterior tone, yet maintains reduced interior resonance.
- Computer controlled mandrel bent tubing for maximum exhaust flow and lower restriction.
Product Benefits:
- Aluminized steel for extended product life.
- Reduced backpressure for maximum exhaust flow.
- Stock factory style hangers for easy installation.
- 50 state emissions legal.
- 100 % American made.
Jmmsbnd007
Diamond Member
COOL! You learn something new everyday 🙂
So... if you had subsonic exhaust, it would be very very super quiet? Does this sonic boom stuff apply to pretty much all engines including 2 strokes?
FrustratedUser
Lifer
The flame itself or the temperature of the exhaust gas?
Gasoline exhaust gas is usually around 700C. for Methanol it is lower, around 400C.
Gasoline exhaust gas is usually around 700C. for Methanol it is lower, around 400C.
FrustratedUser
Lifer
Yes.
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