went from single 3" to dual 3"

[04SilveradoMykk]

..and oh my gawd. What a difference, sure it lost a little mid range torque, but it makes up for it in the high end.

Combo:
357ci Small Block Chevy
Patriot 'Vortec' heads, 2.02"/1.6" valves
Vic jr copy single plane intake, Speed Demon VE 650 carb
Comp XR276HR-10 & 1.6 rollers
.535int / .544exh
224 / 230 - 110+4
Hooker long tubes; 1 5/8 primaries, 2.5" collector

The exhaust was a 2.5" catless Y-pipe into a single 3" exhaust with a single flowmaster Super 40 dumped.

It sounded good that way, minor interior resonance but noticable volume at any rpm level & idle. It would make car alarms freak out...

Now, my truck has the same headers but it has true dual mandrel bent 3" pipes and two Flowmaster Super 40's dumped. It sounds so good, so loud. Interior volume is loud, but no 'vibrating' resonance.

The off idle torque hasn't changed. Yet the engine revs up to the 3200rpm stall of the torque converter much faster. And my Narrow band o2 gauge reads a tad bit leaner (that is better from the previously pig rich) wich tells me the smaller pipe diameter was creating a bit more back pressure than the engine wanted.

I did loose a bit of the mid range 2800-4000rpm torque, but since the engine spools quicker into the higher revs whatever was lost is gained in the high end.

Also, my new true dual 3" exhaust can now support the bigger engine I'm planning on building :burn:

Pics and video will be up soon.

Cheers ~Mykk

[GreaseDog]

my single 3" mandrel bent with a Flowmaster 40 and a single mandrel bent tailpipe will set off car alarms. :dunno:

[04SilveradoMykk]

It's not pretty, but here's a pic of it on the ground... when I have it up in the air later to add turn downs I'll snap a few more pics.

http://i40.photobucket.com/albums/e227/mykk/mufflers-1.jpg

Having the pipes from both banks so close together, I'm thinking it might make it easy to add an X to the system later

[04SilveradoMykk]

Video:

(edit: new link for new vid with all three set ups)
http://www.youtube.com/watch?v=ZPNsNDdkbos

[fast 95]

You have any idle video of it, with the lift of your cam & rockers it should have a pretty choppy lope to it i would think. Sounds good! What are you going to do about the bed cut out now?

[Polecat]

sounds alot better!!

[def1]

ditch the turndowns. get some tips on the end of those mufflers. It will sounds killer.

[04SilveradoMykk]

Well, the Super 40's had an internal baffle rattle... so instead we welded up a pair of Super 44's with a turndown

http://i40.photobucket.com/albums/e227/mykk/super44.jpg

here is a new video including the Super 44's

http://www.youtube.com/watch?v=ZPNsNDdkbos

The turn downs are rough cut and I'll clean them up tomorrow

IMO, I like the Super 40's best... to bad they rattled.

Cheers ~Mykk

[fast 95]

I had an internal rattle that drove my crazy, sounded like a bolt laying in the muffler, dropped the exhaust and cut the muffler open and rewelded the broken internal bracing that cracked and came loose. I would have just changed the muffler for a different one but i like having the x-pipe built in!

[fortplainman]

nice man, you should connect them your your exhaust tip you cut in your truck, just change it from a 1-2 out to a 2-2 out. anyways your truck is badass all the time.

[SierraDan]

Have dual 3.5" tips out the sides where the bed is cut, and add in an x-pipe i'd be willing to bet it'd be a lot deeper and maybe reduce that hollow sound.

[C/Ktruckfan]

IMO, that single setup sounded pretty freakin sweet

[04SilveradoMykk]

Super 40's FTW, the new ones came in and they don't rattle like the first ones. They're welded up and I'm happy.

http://i40.photobucket.com/albums/e227/mykk/super40sII.jpg

[SierraDan]

Pssst: put in an X-pipe :D

BTw, how do those flow as compared to the Super 44? Do you notice a power difference? From what I hear those don't flow quite as well, maybe you increased the backpressure a bit, but considering you have 3" true duals you probably increased torque a bit, that exhaust is huge.

[Polecat]

H pipe should be TQ
X pipe for higher RPM gains.

[SierraDan]

Well his motor is built up a bit so I figured he probably spins it higher than most everyone else here.

[Polecat]

possibly, still a heavy truck...torque is king when heavy.

[SierraDan]

The amount of torque that the H-pipe makes over the x-pipe isn't too significant, I mean his truck is probably fairly light as far as trucks go being a rcsb, don't look like it hauls or tows anything that's what work trucks are for. Our local dealer, Superior Chevrolet uses Tundra's to haul their crap, they don't want customers seeing beat up Chevy's.

[Polecat]

4000 lb truck, is still a truck.

[Polecat]

http://performancetrucks.net/forums/showthread.php?t=395748

3. Exhaust - mid-pipe

The mid-pipe connects the exhaust manifold collectors to the rest of the exhaust system. Different mid-pipes are used for different exhaust setups.

You will not get the full benefits from an aftermarket/custom exhaust without some sort of mid-pipe/crossover pipe. You will have poor, unbalanced flow among other negative things.

For a single exhaust setup, a Y-pipe is used.
For a dual exhaust setup, either an X-pipe or an H-pipe can be used. The X-pipe favors top-end HP. The H-pipe favors bottom-end TQ.

An off-road y-pipe, x-pipe, or h-pipe is referring to one without catalytic converters(cats).

For emissions-compliant applications, gutted cats, high-flow cats, or stock cats may be used.

[04SilveradoMykk]

Just added the H-pipe today, the exhaust tone is so much better. Deeper, way less raspy. I love it. I didn't get a chance to see if the it increased torque, it's raining cats & dogs and I just spin my tires on wet roads anyways.

http://i40.photobucket.com/albums/e227/mykk/Hpipe.jpg

I had no idea it would be so drastic

[chevy4x494]

really??? it helped the tone how?? made it deeper, throatyer what??

[chevy4x494]

do you have cats on your truck?? How far is the H pipe from the headers?

[04SilveradoMykk]

do you have cats on your truck?? How far is the H pipe from the headers?

No cats, I'd say the H-pipe is a good 1.5 feet away from where the one pipe crosses over under the trans and they both run side by side

[91_bowtie]

That's great! Now you just need to find a way to make 600whp, so you can actually flow enough to warrant the big pipes. :lol:

[SierraDan]

Just added the H-pipe today, the exhaust tone is so much better. Deeper, way less raspy. I love it. I didn't get a chance to see if the it increased torque, it's raining cats & dogs and I just spin my tires on wet roads anyways.

I had no idea it would be so drastic
That's exactly what I try to tell everyone when they want true duals, an H-pipe or X-pipe is a night and day difference. I'm not just talking out of my @$$, tons of people say so and i've done it myself.

[chevy4x494]

just added an H pipe to my truck today. You were right, it is deeper. But it also caused it to drone more.

[SierraDan]

Now that i've never had happen. The BBK o/r H-pipe on my Mustang reduced drone, same on my 86 Silverado but I need to rotate the muffler to really reduce the drone, i've got plans for that exhaust.

[04SilveradoMykk]

I need to rotate the muffler to really reduce the drone.

Say wha?

[SierraDan]

Instead of the large flat surface of the mufflers facing up and down like normal, mount them so that the flat parts face sideways and the muffler hangs a bit lower and is higher up. If I could find pics of both i'd show you. You know how when you look at an exhaust diagram it's from the top looking down and you can see the large surface area, imagine looking at that surface when looking at the exhaust from the side.

The reason for this being the large surface area acts as a speaker and bounces the exhaust vibrations off the truck bed and ground creating a bad drone. If it's sideways the vibrations will just move up from under the truck and not vibrate it so bad therefore making it quieter inside. This can all be avoided simply by decent mufflers but my retarded self had to cheap out when buying mufflers for the Silverado. I found out you really do get what you pay for, from now on I buy Magnaflow or Dynomax.