true dual exaust front to rear

[moobypets]

i have and 18 inch magnapack resonator that will be replaced with a 24 soon

as for the y pipe ill have a new one made

and as for the exit for now ill keep my serie 40 magaflow or maybe get the new dynomax VT

 

[Toolman]

mine's running a flowmaster 40 series...sounds like shit, but all V6 SHOs sound like shit to me.

I thought my old SHO sounded perty good

[youtube]FzWmFhRc4Gw&feature[/youtube]

 

[jimtash]

Magnaflow Y-pipe with a Borla cat back on mine and am very pleased with it. Especially considering the Borla cost me $300.00 brand new.

 

[pjtoledo]

on an NA car(no turbo) you want some backpressure. how much is highly dependant on hundreds of variables so each car is unique. having a moderate ammount of backpressure helps in cylinder scavenging and therefor velocity.

on a turbo car you can get away with zero backpressure with no ill effects.

before or after the CAT, that may, or may not be there?

back in the days of old, higher back pressure usually yielded better gas mileage. under 2500 rpms. over 4000 rpms wasn't really necessary, or even an option then.

about that scavenging and back pressure sequence of events, I thought it was

velocity of exhaust gases creates a void in the header and cylinder

intake valve opens in overlap time interval, intake charge see's a lower pressure in the top of the cylinder and header, and makes haste to that lower pressure area. thats the scavenging part.

the intake charge is now moving, but not because of the piston which is sorta hangin' round the top of the cylinder doing basically nothing.


oops!! the fast moving exhaust gases just noticed a low pressure area BEHIND THEM! they ran so fast they created a pressure void in the header. time for an about face and seek out lower pressure area going back up the header towards the cylinder.

(this is where waves and reflections make things really complicated)

some back pressure is now created because the intake charge is beginning to populate the header, AND because the exhaust gases are coming back.


the exhaust valve see's all this and has a mental breakdown because it can't decide between:

A: slamming shut and sealing out what has already passed into the header

or

B: delaying the closing so the returning exhaust gases can ram into and push the "scavenged" intake charge back into the cylinder, which now has lower pressure because the piston has finally started moving down creating a void.


those pesky waves and reflections are really giving the designer a workout at this point.

decisions, decisions. what's a tuner to do?



Damn, must be a slow night if I'm typing all this. :wave:


Perry

 

[pjtoledo]

Hey, after that last post don't think I'm an expert on this billshit. Just think of it AS ********.

 

[gmail]

just to add..
if you build headers for example you can create a lip that keeps exhaust gas from flowing backwards, that would alter sound and flow.

if someone has done this i am not sure but i just wanted to add something to that long thing you typed out

 

[AREA 91]

I think Jeremy had a vid of my car back when he first got it, it was true duals IIRC...

[YOUTUBE]__4F2Gs4b_c[/YOUTUBE]

And as they are now...
[YOUTUBE]QVxPi9gyIKs[/YOUTUBE]

Red one has a Dynomax catback with stock ypipe

my god that sounds bad...
was it just straight pipes?

That firs vid soulds like my pocket bike!!!

 

[revhardSHO]

I had a flowmaster cat back on the 89 and gutted the mufflers. Sounds awsome above 4k and not to bad unless you really get on it. No rasp because of the full length flowmaster resonator. Dynomax IMO seems a bit more raspy.

 

[rit191]

True dual exhaust

My old 91 plus "green monster" had true duals. Also sho shop y pipes. Ran like jack the bear above 3500 rpm. Terrible time getting the right rear mufflers to avoid blatting sounds. Also had problems with pipe knock at the tunnel, but additional hangers solved problem. Definitely a huge improvement over stock system with y pipes.