Size of Exhaust after turbo??
Thread Starter
Staging Lane
Joined: Nov 2013
Posts: 67
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Size of Exhaust after turbo?? Hey guys, I am trying to put everything together before I star the swap of my 5.3 to the new forged 370 with a 76/75 turbo.. Right now I am trying to figure out what size exhaust should I get after the turbo.. Is there certain muffler or exhaust that turbos like??
Thanks guys!
It is going in a RCSB silverado...
Thanks guys!
It is going in a RCSB silverado...
FormerVendor
Joined: Feb 2011
Posts: 547
Likes: 1
Really? I was thinking of doing mine like the old Grand Nationals. I already have 3" Flowmasters and a 3" X pipe. I was going to go from the down pipe to where the X is and tap in there. I know that the chambered mufflers don't flow like a straight through but would it be that bad?
Ah, if there is data to back it up, I will agree then.
I have a Hooker Aerochamber 3.5" muffler on my car...but it is not really a chamber muffler per say....I can see STRAIGHT through the bastard....
I have a Hooker Aerochamber 3.5" muffler on my car...but it is not really a chamber muffler per say....I can see STRAIGHT through the bastard....
For a street car it probably wouldn't hurt it much and you could always use a cutout to bypass the muffler. Keep in mind you can ditch the x pipe and dual exhaust with a single and just run one muffler to save weight. Also if you use a straight through it will mostly add tone since the turbo will also quiet the exhaust a bit.
As for your original question run the biggest pipe that is practical.
As for your original question run the biggest pipe that is practical.
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TECH Enthusiast
Joined: Mar 2012
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TECH Enthusiast
Joined: Aug 2006
Posts: 531
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From: Land Of Enchantment
I'm not a fan of the sound on an LS, but the original American Thunder exhaust on my foxbody was probably the best sounding car I've ever heard. If you didn't have that, you failed the 90's.
My zero percent scientific theory on turbo cars is since the exhaust pulses are bouncing off the turbine, it's already quieter than an NA/blower car. You can get away with a lot. If you can see straight through the muffler, it should be good to go. Diameter should be as big as you can fit under the car.... plus a 1/2 inch.
My zero percent scientific theory on turbo cars is since the exhaust pulses are bouncing off the turbine, it's already quieter than an NA/blower car. You can get away with a lot. If you can see straight through the muffler, it should be good to go. Diameter should be as big as you can fit under the car.... plus a 1/2 inch.
TECH Enthusiast
Joined: Mar 2012
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Honestly no point in a 5" exhaust if the turbine has a 3" outlet. It'll cost more, be harder to find clearance for, and could possibly even give poor wideband readings if your wideband is placed too close to the turbo. You likely wouldn't see any gains over a 4" either.
But.. 
I hope someone puts fact and truth to exhaust systems and there diameter soon.
Is there anyone that has dyno numbers or track numbers to show any improvement from going from a 3.5" to a 4" or 4" to 5"???
Is there anyone that has dyno numbers or track numbers to show any improvement from going from a 3.5" to a 4" or 4" to 5"???
TECH Enthusiast
Joined: Mar 2012
Posts: 728
Likes: 3
Less pressure after the turbine means less resistance on the turbine. If you can evactuate the exhaust better once it exits the turbine, it'll help (although marginally), reduce some of the overall backpressure. Of course when you have a 3" outlet and a 4" downpipe, going to a 5" isn't going to help any more. Infact, going too large can create uneven flow in the downpipe and throw off EGT gauges and widebands.
On The Tree
Joined: Nov 2007
Posts: 103
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Here's a cutaway of a flowmaster (chambered) muffler. Tell me how many 90+ degree turns you see the exhaust flow having to make. This is why they don't work. Sound great? Hell yah. Flow?. No chance in hell. Inlet's at the top.
