Educate me

8.1Texan · April 29, 2003

First post...been lurking for quite some time trying to educate myself on a few things I know I am ignorant on.

So, my first question is...there are a lot of systems out there for my truck (2001 2500HD 8.1 ZF6), most of which seem to be the single out. so, what is actually being changed when I buy a full "cat-back" system? Just the muffler and a tip? Does this truly offer any advantages?

also, I have seen people often refer to a "True Dual" system, how does this differ from other systems and what are the benefits/disadvantages?

And yes, I have done multiple searches on here, and even though there are a few hundred topics on exhaust systems, none of them offer a good educational background.

Thanks!

Kania2k1 · May 5, 2003

On my cat back, I got the flowmaster American Thunder system, There is a "resonator", then the muffler, then the pipes out the back. I'm not sure about the stock exhaust on the 8.1L, but I would say it is similar to the 5.3's. Exhaust manifolds, cat after each one, the to the muffler then pipe. I've heard that the low end torque is lost, but I haven't notice any, seat of the pants testing. as for the true duals, in this system, instead of the Y pipe after the manifolds, the exhaust exists, straight back, or side, whatever. Usually, there is a crossover pipe somewhere in the system to balance the pressure, I think that's why, and make it more even like. I'm by no means an expert, but I think that might answer some of your questions.

8.1Texan · May 6, 2003

I appreciate your reply. But what i'm really wondering is, are there any real performance gains? or does it just sounds nice? if that is the case, why are whole cat-back systems sold, and not just the muffler.

BadBowtie · May 6, 2003

IF I remember correctly, Dynomax's website has some dyno information, but I don't recall if it is for mufflers or complete kits. Edelbrock usually also has dyno info for their parts.

www.dynomax.com

www.edelbrock.com

95whtZR2 · May 6, 2003

8.1Texan Posted on May 05 2003,10:32
--------------------------------------------------------------------------------

I appreciate your reply. But what i'm really wondering is, are there any real performance gains? or does it just sounds nice? if that is the case, why are whole cat-back systems sold, and not just the muffler.

Yes there are performance gains over stock exhaust setups. Depending on what performance you want to get out of it depends on how much you want to spend. The main reason, I assume, that they give more performance is better flow, it frees up the engine and therefore giving it more power. However, when someone takes off there whole exhaust system it creates incredible flow, but no backpressure; therefore, with no backpressure you can burn out the exhaust valves, and do other types of dammage. Usually with better flow it also make a deeper sound (less restriction in the muffler/catylitic converter)

Also with the catback systems, a lot of the time the echo tips creates the majority of the sound. That is why when people put flowmasters etc. on and leave there stock exhaust exit with no tip, they complain about how it is louder but not loud enough and there buddy has the same setup (except with tips) and it is louder. I am not sure if the tips are good for performance or just sound/looks...

Good luck with your exhaust, I should be getting mine in mid-June, and can't wait to free up my jimmy, hoping to take a few tenths of a sec off of my 1/4 then I will be in the 16's.... that sounds a bit more impressive than 17.2...

Tom

8.1Texan · May 6, 2003

Okay...so when a cat-back system is put on, a larger diameter pipe goes on?

That is what I had originally thought, but while reading on this forum, I saw that people were replacing their exhaust with systems with the exact same diameter as the stock exhaust.

and i'll tack on a second question...why do B&B triflo systems cost an arm and a leg? so much more than others than I have seen? I have found that in most areas of life, you get what you pay for...are these systems that much better?

Frank S · May 6, 2003

It doesn't necessarily mean that a larger diameter pipe will be used but it is not uncommon for that to happen.Alot of the times the same sized pipe will be used with a larger tip at the end for appearance purposes.

Where you get your better flow is by replacing the more restrictive stock muffler with a freer flowing one.You may notice a slight loss of power in the lower rpm ranges due to lost backpressure but I doubt this would be your case with the 8.1 as the engine is designed to make great power in the lower rpm ranges.

Usually people go with an open element intake along with a freer flowing exhaust system.They are great complimenting modifications because the intake will allow more airflow into the engine while the cat back will allow more rapid exhaust dissipation and you will definitely create more power throughout the rpm bands with those two mods working together.