I ordered GIBSON Dual Extreme Exhaust along with JBA ceramic coated headers,

will post pics and track numbers ASAP


Thanks,

 

The theory behind the dual exhaust and single exhust is pretty simple. The single exhust is better for low end torque because of the exhust pulses. At low speeds the pulses from each cylinder 'help' to suck out the pulse just behind it. This is lower end (torque) benificial. A dual exhaust has half as much 'help'. But as the RPM's go up the amount of pulses in each pipe goes up and the 'help' is now there. Now you have a higher top end (horsepower).

A "tuned" exhaust is one that has been calibrated (by size and length of pipe, location of muffler and/or resonator) to a specific engine and an optimum speed.

And torque has a direct correlation with horsepower. Torque is calculated at a specific RPM to get a HP #. The formula is as follows:

Torque X RPM
-----------------
5252

One thing to note on this. The torque rating and the horsepower rating will always be the same at 5252 RPM. That is to say if an engine has 287 HP at 5252 RPM then the torque rating is 287 lbs/ft at the same time.

I am sure that is way too much info but there it is......some usless cocktail party trivia for you all.

Eric

 

5 speed,

thanks for the info. It definitely was not too much. The way I posted the question to your answer the other night was even longer. ("dual exhaust for hemi"). If you have any additional feedback on my question I'd love to hear that too.

 

Hoopdad,

Three questions that I would ask to answer your exhaust question.

1. What is the main use of the truck? Is it used to commute most of the time?

2. How much 4 wheeling do you do? And if you do a fair amount, how much of it is dependent on low speed control of the throttle?

3. How much and how often do you tow if at all? How much does the trailer weigh?

Give me some more detail and I can steer you in the right direction. Personally I think that the exhaust is way too thought-out. Here is my opinon in general. A good set of quality headers feeding the stock cat-conterter. Then it is just a matter of do you want it dual or single? Loud or mellow? Do you want it 'show' or 'go'? The answers to these question and the questions above will dictate the proper exhaust system.

The aftermarket has a lot of great stuff. They bolt right in, sound good and look good. But in my opinion the money spent on these high-end cat-back systems would be better spent on a set of good headers and a simple muffler change. I worked in a muffler shop for a while and have built-up many cars over the years (it started with my 1976 Dodge Colt and went down hill from there) and have learned to weigh the $$$$$$$$$'s to the intended outcome.

That is to say that a $600 bolt up cat-back system is nice. But a $150 muffler (Flowmaster, Dynomax, whatever) only loses a few horsepower over the high-end system. And I now have $450 for (pick one) headers, new HI-PO computer, free air intake, yada.....yada....yada that will far exceed the few HP lost with the muffler only. Get the point?

Eric

 

Thanks for spending your time to give me a detailed answer.

My question comes from two motivations. First, I am trying to understand how it all works in the general sense. Then I am trying to figure out what , if any, exhaust upgrades I would like to do.

Sadly, I primarily drive my truck for commuting to work, trips to the store etc. The only times I have put it in 4WD were for hauling brush from a fallen tree in my backyard (didn't want to do donuts on my front lawn); trips on the dirt road to the dump to dispose of that brush; and some "shortcuts" on dirt roads. Come winter, I'm sure I'll be putting it in 4H on my way home from work or the store - they plow our roads last. (I live in eastern Connecticut.)

I also don't really use it for towing; the only thing I ever towed was a friend's wood splitter. But I also have only had the truck 3 months, and never owned a truck before so I might end up using it more than I am now.

I'm interested in how to make it go faster, basically. Merging with traffic or passing on a country road are easier with more power. But when I am not in a hurry to get home from work, I'd like to save gas mileage, like when I drive to work and am really in no hurry. When I started reading that performance was potentially degraded, I became more interested in the basics of how it works.

Thanks again for your feedback.

-Mike