Saturn ION RedLine Forums banner
1 - 20 of 21 Posts

·
Registered
Joined
·
1,909 Posts
Discussion Starter · #1 ·
sup all i finally got my muffler/s i bought the magnaflow race series and obx greddy style both 3"inlets. My plan was to do 3" from the cat back but im weiry now! What size of piping should i use :confused: some people have 3" some have 2.25 what is good for HP and TQ (i dont care about sound :eek: )

thank you all appreciate it!
 

·
Registered
Joined
·
3,574 Posts
I hope you mean 2.5", not 2.25". By saying "mufflers" I'm assuming you're doing a dual exhaust set up, right?

Well, since your mufflers are 3" already, go ahead and take the rest up to 3.


I'm staying with 2.5" myself but I'll be adding one little trick to it later on. :D
 

·
Premium Member
Joined
·
3,231 Posts
I got 3 inch to 2 2.5 mufflers. The noise sucked until I droped in a resonator. Get a resonator trust me there. 3 inch isnt to loud though. Jared has 3 inch all the way and it makes quite a grumble.
 

·
Premium Member
Joined
·
3,231 Posts
still gotta make that damn video.
 

·
Superd00d
Joined
·
22,040 Posts
What kind of resonator did you use Goofy?
 

·
Premium Member
Joined
·
3,231 Posts
I dont know. They were marked maganflow univeral. I have a 24 inch long 3 inch in/out which made all the differnce. Without it the car was raspy and sounded like crap.
 

·
Registered
Joined
·
1,909 Posts
Discussion Starter · #7 ·
were can i get this resonator! im running one muffler (just a bad speller) so is 3" piping to 3 inch muffler goin to hurt performance? that is my question ;)
See i herd with superchargers you get alot of gains from exhaust, if so i wanted to get weapon R header to a high flow 3" cat, then 3 inch piping to a 3"muffler :D will i see substantial gains w/ this or not?? Im not asking for 500 hp ;) but im trying to beat my boy im so close now with intake but not enough! :eek:

He has WRX with intake and cat back exhaust i run with him he pulls then never gains no more than a car :eek: so now i need more power!

thanks all!
 

·
Premium Member
Joined
·
3,231 Posts
I got mine at the exhaust shop that did the exhaust for me. He welded it in for free. Find the same size in/out that you are using and as long as possible. The longer it is the deeper the sound.
 

·
Premium Member
Joined
·
290 Posts
we have a prototype 3 inch header back exhaust for sale. it is all tig welded stainless and has a 3 inch high flow cat. anyone interested let me know via PM ***local pickup/install only***
 

·
Registered
Joined
·
391 Posts
you mean it can be boxed and shipped?... dangit! what muffler are you using?
 

·
Premium Member
Joined
·
290 Posts
BlackLine said:
you mean it can be boxed and shipped?... dangit! what muffler are you using?
it has a stainless resonator and stainless straight through performance muffler in stock location. naaahhhh we want to sell this locally but its a very nice system fabricated in house by anthony!
 

·
Registered
Joined
·
1,550 Posts
I would certainly go with the 3", especially if you plan to up the boost down the road....
 

·
Registered
Joined
·
1,550 Posts
That's quite possible if the car was otherwise stock (or close). 3" would be benificial with a bit more boost, though, so why limit yourself? A couple more lbs of pressure with a smaller pulley would make it all worthwhile.
 

·
Registered
Joined
·
2,110 Posts
dazednconfused75 said:
I just read that rev it up motorsports lost power using 3" instead of 2.5" on the SS.
I have heard that too here on this forum. I am not questioning you, but I was wondering if anyone can explain the science behind that. Isn't that goal to get as much air/fuel into the engine (either NA, or in our case via a SC), burn, and get it out of the engine as fast as possible, with as little back pressure as possible.
How is a bottleneck (albeit small, 2.5" vs 3") beneficial to HP?
 

·
Registered
Joined
·
4,352 Posts
not be a pain but to quote me :

okay lets get something first here. you are dealing with a supercharger. not a turbo. these are 2 very different animals!!! not similar in almost any way except both pumping air out of them. sc's work on the intake side of things. thier job is to suck more air in and pressurize it i.e.= more air= more oxygen = more fuel burned= more power. simple (well explaining it is ) just like a normally aspirated engine a sc needs some backpressure to maintane good flow and turbulance. yes i said that. there is a sort of phenonminom that happens inside pipes that have air flowing through them regarding the "tuning" or "frequency" of the air many use different terms for this but its all the same. harmonics. think of a large pipe organ at a church its really very similar. air will flow at different velocities at different tuning frequencies. i build competition subwoofer enclosures all day. we deal with the in car resonance, cabin gain etc... all which gets figured in to any real competition system. if you go to an installer and he doesnt do enough testing and research on your vehicle and you are paying him a lot of money GO ELSWHERE!! if they do not know what all this stuff is you will not win plain and simple. if you go to large on a all motor car you can and will kill your power very easily. you generally also will only gain anything and if you do it will usually come at the top of your rpm range. to big with a sc is not the way to do things. call any large sc company they will tell you the same thing maybe not word for word but it will come out the same. jackson, ripp, eaton, vortech, etc......
i could get into it more in depth and into turbo's as well but that another time and place

and to quote planetslowcar1:

Amazing! That's the first time that I've EVER heard anyone online explain exhaust flow correctly. Usually its just, "Backpressure ownz joo, yo needs it fo torque."

Now if we could just get people to talk about HP and torque correctly this discussion could really be intelligent and informative.

If nothing else, let's just try to avoid using "torque" as this catch all term for low end power. When you slap on a huge exhaust, you don't lose torque. The engine probably makes more, it just makes it at a much higher RPM. Even more so than the misunderstaning of exhaust flow, its the misunderstanding of HP, torque, the power band, and how they relate that causes the exhaust size discussions to turn into mass stupidity contests.

As for STREET (that means full car length) exhaust. Just think of it like an intake manifold. The flow is optimized to make torque at a certain RPM. Smaller sizes make more down low and less up high. Larger sizes make less down low and more up high. The trick is to find the best balance of flow (biggerness lol) and velocity (smallerness). But it has NOTHING to do with backpressure making torque or the load on the engine. It has only to do with optimized scavanging and velocity and what RPM that occurs at.

Think of it this way.

A smaller exhaust will have a higher velocity (ideal gas law) but less flow (common sence). At low RPM, the small pipe is easily filled and the velocity is good. That decreases backpressure and makes good low RPM torque. But as RPMs build the engine is exhailing more than the exhaust pipe can smoothly flow. That makes backpressure and kills high RPM torque.

A large exhaust will work opposite. It will have lower velocity but more flow (at any given RPM). So at low RPM the huge pipe isn't filled enough for the gas to have good velocity (ideal gas law again) and that makes the gas tumble. That reduces flow and creates backpressure, killing low RPM torque. But at high RPM the large pipe is now filled correctly and the velocity is high. Now you have very little back pressure and that frees up high RPM torque.

So they both have their uses. Again, sizing is key. Just like sizing a turbo to fit the engine's flow (CFM), your driving style, and the operating RPM. Its the same for exhaust. But notice the VERY KEY part of all that explaination. In every case backpressure is what kills the power. This is why race exhaust (a large diameter dump pipe) usually makes gains everywhere. When the exhaust is extremely short the ideal gas law doesn't matter. The pipe is so short there's no time for the gas to tumble, back up, speed up, whatever. The only time you have to worry about tuning for velocity is when the exhaust is the full length of the car and you need to keep it flowing out a long pipe quickly.

In conclusion.

BACKPRESSURE DOES NOT MAKE TORQUE.

I hope that was all helpful and will prevent having this discussion every other week on this board (like all the other car forums).
 

·
Registered
Joined
·
2,110 Posts
zfactor said:
not be a pain but to quote me :

..............

I hope that was all helpful and will prevent having this discussion every other week on this board (like all the other car forums).

Thank you, that really helps, I apoligize if this has been explained elsewhere....
 

·
Registered
Joined
·
2,070 Posts
matt said:
3" seems like overkill unless you have quite a few mods.

I guess it depends on what your plans are for your car. I might have to opt for 3" because this car already has quite a bit on the low end of the tach but seems to lack up top and I'm sure that will become even more evident as the mods pile in.
 
1 - 20 of 21 Posts
Top