I'm running a two chamber Flowmaster on my truck, dumped after the cab. And one person on here has told me that by switching my Flow master to a Magna Flow that I would get a better response. What the difference between the two ? I'd like to a comparitive chart that shows actual numbers, But I guess thats wishful thinking.

I'd like to know the difference's between Gibson, Magna-Flow, and Flow Master. Anyone have some hard evidence that they can post up or link.

 

I don't think anyone has dyno tested such things to get real numbers. But, take a look at the Flowmaster design vs. Magnaflow. Magnaflow is basically a glass pack, straight through design which is godo for flowing air. Flowmaster isn't exactly the master of flow design with baffles to disrupt the air. I'm not sure what Gibson looks like inside. Would you notice any difference? I don't know. Is it worth $100 for you to try it?

 

I have had similar setups with Gibson and now Magnaflow on my Expy. 3" muffler with 2.5" pipes.

The best fact I can give you is that in the past, trips into the Texas hill country required a few downshifts on the highway. Last November after the Magnaflow install I made the trip having to press the pedal down a little but never enough to make the trans downshift.

 

I hear what you are saying about the design's of the Mufflers. Don't you think that there has to be some other data out there !

If anyone knows or has some hard evidenance, Please post up ! I really don't think by changing your muffler to a Gibson, Magna Flow, Flow Master ....... etc is going to change your HP that much. Anything besides the stock muffler will change your HP noticeably. But when switching name brand mufflers as mentioned above, your probly only going to get +/- 5 HP difference. And to me buying a new $100.00 muffler to gain +/- 5 HP is not worth it.

But on the other hand if someone can post up some reliable information to prove me wrong. Then I may be wrong !

 

i thikn the flows free up too much back pressure. by keeping just the right amount you can gain torque. i think thats what magnaflow does

 

Markus, it seems as though most people who change their exhaust want a different sound and or look, with performance (as long as it doesn't hurt) ranking last. Not all, but many. I agree that replacing just the muffler will probably net 5hp gain at most.

 

Well said APT, I think you're exactly right. Considering that, has anybody just gone to their local muffler shop and told them to run two pipes from the muffler back, or would doing something like that amount to blasphemy on this exhaust board?

Just wondering as I'm in the market for duals but not looking for something real loud or powerful (although the increase in power I keep reading about via these "complete" exhaust systems would be nice)

 

packager_jr,

You are considering just using the stock muffler, a y-pipe and then dual tail pipes and tips? You want the look, but not a loud sound? Blasphemy? No, it is your truck; do what you like. But I recommend just changing the muffler to a single inlet/dual outlet one instead. The stock muffler is very restrictive and you can gain some, especially since you are helping with tail pipes too. A good y-pipe costs about $25 and a SIDO stainless muffler about $115, less for aluminized. There are some brands of mufflers that are not loud, yet yield impreovments in flow. I like Magnaflow.

I recommend buying these tail pipes that are already pre-bent. It will cost less than having a local shop custom bend them, and they work with the spare tire in place and are mandrel bent for the best flow.

 

How is going to my local muffler shop and getting a SI/DO glass pack with dual pipes out the rear any different from buying one of the aforementioned name-brand kits? is there some performance advantage in the name-brand kits. Or is it just a way to get a bunch more moner out of my hands?
I can get cat back duals with the glass-pack for $165 at my local shop. Waaaay cheaper than the kits, plus, I don't have to install it myself.
If there is some kind of real advantage to the kits, I would shell out the extra $$, but if not.....

Thanks

 

Rebel -

Don't know how different it would be. The systems I've seen seem to be basically a muffler and some tailpipes. That's why I'm trying to see what other options may be out there.

ATP -

Thanks for the help. I've been reading your posts from both exhaust sections and they are always helpful. Let us know what you decide to do for your 5.4 (I did read you may modify it this spring?) - I'm sure alot of us would like to know. Thanks,

Mike

 

I am a **** about this myself, but havng pipes that are flow tested by a mfgr, and not just bent into shape by someone is always best.
If you have a good muffler shop that is reliable and knows how far he can and cannot bend tube, it should be ok, but the best best is where you can, get a system that has something behind it other then "that looks pretty good".
If you shoot for True Duals, then this goes out the window, as some custom bending needs to be done, but it should only be at 90* for the drivers side, and straight back for the most part from the pass side. With this, you need to have a repetable shop, else they can make a system that is really for crap and a lot of money for nothing ( I am up to ~ 900.00 for parts, and I still have yet to have my dual installed ).

While I don't want to imply that you need to speed a crap load of money on a system, spending a fair amount is better then the bargin basement type fo system that in the long run might need to be taken out, and redone to correct an error if it happens.

 

Well, i had the custom bent system with the glass pack splitter (SI/DO) on my last truck. It seemed to be a quality exhaust done by a guy who has years and years of experience. It held up fine for the 3 years I had it. It is not durability i am asking about. I am curious about the performance aspect. It seems by reading here that certain systems are supposed to be better at providing a performance enhancement to the vehicle. I am just wondering, from a performance point of view, how a "kit" which costs at least twice as much adds more performance than a custom built system by my reputable local exhaust shop.

I am completely open-minded about this and ask this because I want an exhaust which sounds good, enhances performance, especially low end torque, and does not take away anything from my truck's performance. I like the sound, but I am not willing to sacrifice one bit of performance just for sound.

If it costs twice as much as my local shop's system, so be it. I would like to know if it is really worth it before I buy a "kit" and I figured this is the best place to find out.

Any advice from the exhaust guru's here would be greatly appreciated.

 

It is very simple, RebelYell, research, design, and testing. A company manufacturing exhaust products has the budget to test fit many products to test vehicles and then use a dyno to determine what the best is. There are many factors which affect the performance of an exhaust, including the diameter of pipe used, the shape of the pipe, the type of bends, the design of the muffler, etc. An exhaust shop just installs products. No testing and feedback as to what the results were. Most aftermarket exhaust modifications will provide an improvement by feel to the customer, and he is satisfied. But did he get the most performance? Who knows? Very few of customers test the power before and after to verify.

I didn't understand complete systems either. I didn't think they were worth the extra money. I knew similar performance could be had making up a custom one, and still think so. But it is a chance to take, and unless one tests the real differences, he will never know for sure if his custom setup is better than anything else.

BTW, I don't think a kit costs twice as much as a custom job if you consider similar components and materials.

Packager,
I don't think I will get a chance to do exhaust mods this spring. I overestimated my tax return, and I'll be very close to breaking even. Maybe if my wife gets a bonus.... But I won't be dyno testing either before or after so what I do shouldn't really matter to anyone else. My truck does everything I need it to quite comfortably. The only thing I could ask for is better fuel economy. But I made the choice of power over fuel economy and won't sacrifice it.

Aaron

 

IMO I think that irregardless of what exhaust sytem i.e. a catback system you chossed you not gonna see a super drastic HP increase any increase you may see is gonna be very discrete. Like many posts before it seems to be a sound/ looks thing and maybe a nominal performance gain unless you go full headers hiflow cats and a good catback your not gonna feeel a wicked SOTP feel. I myself will swear by magnaflow I have a DI/ DO on my 00L and it just gave it a really good tone throught the rpm range and a mean tone at WOT. Did not feel a HP increase or decrease all I know is it flow better than stock. I personally am not a fan of Flows I had them on one of my Z28's it was loud but very droning on the freeway and extremly raspy. Unlike the magnaflow which is realtively quite untill you get on the go pedal. I pry didn't answer any questions just thought i'd share my thoughts..

 

RebelYell:

I have had both the si/do Flowmaster 50 series, and a si/do Glasspack that I am currently running. Pickup and sound were noticeably increased, as the straight through design of a glasspack allows for much greater airflow. I'd say go with the Glasspack!

-Flea