Alright....

Seriously considering this option right now.
I have true duals that are non-mandral bent through magnaflow mufflers. High powered N/A 402ci. Makes 523 RWHP through that current exhaust and a 9".
Anyways...I know there is more.

My biggest problem is that the duals fit so tightly through the torque arm bracket that it bangs at idle. Sometimes pretty bad. Cam is a little big so the exhaust rocks with the lope.


This is what I am considering...
Running duals 3" cutouts about 12" off each collector, then running a single 3" pipe to that back through the same mufflers.
Not really concerned with HP numbers on the dyno...but I am concerned about track numbers.

Discuss please!!!!

Pros:
Should flow better and gets rid of the rattling.

Cons:
Tamer sound for daily driving.

I say go for it. If you don't mind what are the specs of your cam, I've been wondering for a while?

248/254 at .050
629/622 lift
113 LSA

Straight-through sidepipes!

With those HP numbers I'd be more worried that going back to a single 3" might put a restriction on the engine and cause fuel/air flow problems on the upper end. If you go that route, only use mandrel bends, keep the radi of the bends as large as possible and avoid 90* bends where ever possible. That will help keep restrictions to a minimum

Of course it would cause a restriction. That would kinda be some of the point. A tamer street set-up then open the cutouts for track, dyno, etc.

Not worried about performance with the cutouts closed.

just cut it off at the headers man! or where the crayon stops melting

i have always liked the true duals with an x pipe that dumps before the axel. You just have to have the ground clearance for it.

That is fine and dandy if I didn't have the rear cover of a Trans Am.
Dumps is fine with a Camaro, but the Trans Am has the cover made for exhaust tips.

Should have the cutouts ordered by Sunday.

yeah i guess you're right

Not worried about performance with the cutouts closed.
I'm not referring to performance loss, I mean loss of driveability. Every exhaust system has some restriction, we're talking about restriction to the point where it severely affects the engine's ability to breathe. Now, if you had a skimpy 2.25" dual exhaust on it and were to go to a 3" single you'd actually see gains in exhaust flow. but if you have dual 2.75-3", you are going to suffer a loss going to a single 3", hard to say how much though.

You've got HP Tuners right? is the exhaust bang bad enough to cause false KR?

You've got HP Tuners right? is the exhaust bang bad enough to cause false KR?
At idle we think it has.

yea that's what I figured... that's bad lol


cutouts

i dont have a lot of experience with late model camaro exhaust but i have seen many different combos in magazines and many remain a single exhaust even with extreme engine configurations.i cant see a single 3" being a big issue, thats a big pipe.and if im not mistaken isnt one side of the tailpipe a straight thru, not passing thru the muffler?

are you going with electric or manual cutouts? just curious.

if you do get cutouts dont get the ones with the wingnuts, get like the cable operated or electric ones. more convienent(sp?) and you can just flap em open when ever, like if you race on the street ever. like a honda rolls up thinking your stock and takes off you flap em open and he shits his pants and gets served on a silver platter with the apple and everything.

If you don't mind me asking what kid of motor mounts do you have I'm assuming with the 402 your running a urathane setup. What about dual 2.5" out the back then step it up to 3" past the Torque arm bracket (on the tunnel or on the 9" by the way?) That way it'll flow good and when the exhaust gas starts cooling down to expand it'll be in the 3" pipe. Also Mandrel Bends will open it up and help the flow You could run that through the mufflers and If you wanted the tru duals you could set that up in the pipes. Just expanding your options.

Nate

Sorry to respond so late.

I have decided.
Dual 3" cutouts are being delivered next week. Non-electric. The electric ones get clogged with carbon so I went basic.
Gonna cut down the duals to 2.5"....I think. Depends on the cheapest route to free up clearance with the current set-up.

Car should sound the same as it does now on the street...but maybe a touch quieter.
When the cutouts are open.....you can figure that one out. :lol:

are they the cable operated cutouts or the ones you have to go under and thake the wingnuts off?

I have to take them off.
No biggie, I didn't want the electric ones anyways...they get clogged with carbon.

I have paid for the cutouts...but dude is wasting my time with the shipping.

electronic ones not only will carbn clob but the motor will burn out turning it into a manual one anyway... so good call there

They will be here next week.
Shipping was an error in the UPS system I guess.

Hoping they show up Thursday...I will drop the car off that night if that is the case.
Meaning next weekend there should be a little open header video clip up. :lol:

The Trans Am is at the exhaust shop. :icon16:

Can't wait to see it!!!!

Friend has a stock catback.
Thinking about putting that on.
Tame sound and no banging for street use.

LOL

Wow.

???

Imagine large cammed LSx 402.
Running open headers.

And there you go.

I ran open headers on my bolt-on LT1 and it sounded like a monster. After the first time I drove it, I lost some hearing. I can't imagine what a built cammed 402 LSx sounds like. I'm actually kinda frightened.

Dyno time tomorrow. :lol:

Video to follow. hehe