Stack exhaust pros n cons?

[hayzin]

Salaam PW brothers,

I have had this idea for a while now. But I need to know the pros and cons of stack exhausts on 4x4 machines vs regular tail pipe exhaust systems.
I have seen a 3-door RKR with stack exhaust system in Islamabad, and it looked very 'interesting'. However, as far as functionality goes, is it worth it?
My concerns are:

1. Does it have any effect on performance?
2. How loud is it in the cabin?
3. Does the 'dholki' in the middle have to be removed?
4. Will the paint on the roof get damaged? (depending on positioning)
5. Any safety factors to consider since it will be hot when running and if touched can be harmful?
6. How many inches in diameter would be practical?
7. Where in Islamabad can it be done?
8. Dual stacks or single?

These are some of the questions I have. I have read up on some forums online, in the end, it seems like a 50-50 thing. People who have them on their 4x4s love them, while others think that the loud factor can get annoying after some time.

What do you guys think?

[alijees]

I think firstly it depends on what kind of 4x4 you are wanting to install it on.
Then you have to decide if you want it on the rear or front.
I think 5inch is a good size to work with.
The 'dholki' I would suggest should not be removed to that you can control the sound a little bit.
Double pipes will look better I think.
Also flatbed trucks naturally look better with double like the pic u have shown.
You can easily find the tractor exhaust in Saddar, Pindi.

[hayzin]

I think firstly it depends on what kind of 4x4 you are wanting to install it on.
Then you have to decide if you want it on the rear or front.
I think 5inch is a good size to work with.
The 'dholki' I would suggest should not be removed to that you can control the sound a little bit.
Double pipes will look better I think.
Also flatbed trucks naturally look better with double like the pic u have shown.
You can easily find the tractor exhaust in Saddar, Pindi.

Thank you for the info Ali Bhai!
If i get it, it will be for my BJ60. I can only install a single pipe because I have a snorkel on driver side.

[hayzin]

any 4x4 enthusiasts want to pitch in?

[sami_voodoo]

I'm no exhaust expert, I'm only pitching in from what I know about engines. Generally, the longer the tube (for the same diameter), the higher the the difference in pressure between the inlet and outlet of the pipe.

In practice, your exhaust outlet is at atmospheric pressure. The inlet to your exhaust pipe in a turbo diesel would be the turbine outlet, or in an N/A diesel, the exhaust manifold outlet. Your turbo or N/A exhaust pressure would be higher for a longer tube as compared to the shorter tube. So generally, the shorter the exhaust pipe, the lower the pressure difference along the exhaust. This helps in increasing volumetric efficiency of the engine, and power.

Problem is, you can't just went it to the side. Sitting at idle at a traffic light with the window open, the hot exhaust gases will rise and enter your cabin. Exhaust gases being toxic with particulates, NOx and other nasties, it's best to route it elsewhere. Stacks help do that, they exit at a higher point than car windows, and even when the car is moving, they keep exhaust away.

[hayzin]

Thanks for the info brother, I ditched the idea of getting it done on my LC.

I'm no exhaust expert, I'm only pitching in from what I know about engines. Generally, the longer the tube (for the same diameter), the higher the the difference in pressure between the inlet and outlet of the pipe.

In practice, your exhaust outlet is at atmospheric pressure. The inlet to your exhaust pipe in a turbo diesel would be the turbine outlet, or in an N/A diesel, the exhaust manifold outlet. Your turbo or N/A exhaust pressure would be higher for a longer tube as compared to the shorter tube. So generally, the shorter the exhaust pipe, the lower the pressure difference along the exhaust. This helps in increasing volumetric efficiency of the engine, and power.

Problem is, you can't just went it to the side. Sitting at idle at a traffic light with the window open, the hot exhaust gases will rise and enter your cabin. Exhaust gases being toxic with particulates, NOx and other nasties, it's best to route it elsewhere. Stacks help do that, they exit at a higher point than car windows, and even when the car is moving, they keep exhaust away.