This is my exhaust system. Headers, 2 1/2" pipes, H-pipe behind the headers, and 3" Flowmaster 50s. Everyone loves the sound, people look up the street to see what bad **** is headed their way. At one half throttle, mothers grab their kids and run indoors. At wot, my buds slap high five, and mustang drivers try hard to catch up. Everyone loves it..... except me. Imagine the "wipeout" drummer back in the hatch area, drumming wipeout all the time the engine is running. He drums faster and louder with throttle, but at cruise, about 2000rpm in fourth, he really resonates.


I didn't think an X pipe would make any difference because I already had an H pipe. But my muffler guy had this x-pipe laying around, and nothin' from nothin'. We tried it. Wow! What a difference. The drum sound has been replaced with a higher pitched roar, and the overall volume is down. I think the wife and I can have conversation now. I'm a believer, and I love my flowmasters again. It doesn't look like much, but it works.

This is what it used to sound like. I'll have to record the new sound.

After X-pipe installed:

Bee Jay

 

Thats where I installed my X pipe too. It does improve the sound .....lot less resonance at cruising speeds.

 

So in the picture you have an H-pipe and an X-pipe.... interesting.

 

Yep, Didn't expect much from the X pipe since I already had an H pipe, but I was surprised. Maybe someone can explain why. I would advise anyone with an H pipe and their system is still too loud, try an X pipe before you toss the mufflers. I drove the car to work this morning and I had a conversation with the wife. Tonight I'll try the stereo.
Bee Jay

 

Do you feel the overall volume was lessened inside the car and out, or was the resonance inside the biggest improvement?

 

Sounds quieter in the car and when I stand behind it. I knew immediately when my muffler guy fired it up to check for leaks. It still has a healthy bark and is not near as quiet as a new Vette.

 

I am surprised that more people don't run an X-pipe. I did some DynoJet runs a few years back that showed a measurable horsepower difference between no X-pipe and with an X-pipe.

The sound is just the icing on the cake.

Steve

 

Was my H pipe doing anything for me?
Bee Jay

 

My experience on the DynoJet says no. Others may disagree but this is just what I have seen.

Steve

 

And my experience with an X-pipe was very unsatisfying ....
produced an extended resonant drone from 1200 right through to 2200, and lost all its characteristic 60's muscle car v8 burble.
Sounded like a late model single pipe LS1

To each their own, I guess.

I removed it, and now only have a narrow band (1200~1250rpm) where it drones. And it sounds like a muscle car again. Don't sit at that rpm, so not really an issue now.

The combo of H pipe and the location of X pipe further back is obviously a new approach. Keen to hear the new system.
cheers
tom

 

Someone commented that my exhaust sounded smoother and didn't have the harsh bark anymore. He didn't know I had modified the exhaust, so that was an unsolicited comment. He likes the sound. I like growl more than bark too. I guess since I have both the H pipe and the X pipe, I have no drone or resonance now. Another benefit, I can hear the tires losing traction now, instead of just feeling it.
Bee Jay

 

It's actually very important as to where you place the pipes.

There's a technique for picking out where to place an H-pipe which involves painting both sides, driving the car, finding the hot spots and then connecting them via pipe. I'm sure there's a technique for X-pipes as well, but I'm not aware of it.

 

I found this in the October 2008 Motor Trend test of the ZR-1.
"The difference between the 7.0 liter basso rumble and the ZR1's baritone roar is striking. Sure there are bigger lugs on the Z06, but the difference has more to do with what happens in the tunnel. Both use two big pipes with a crossover, but the Z06 has an H-configuration with a short connector pipe that simply allow the reverberations to bounce between pipes. The ZR1 uses an X connection that commingle the actual exhaust. The H-pipe setup tends to preserve a slightly rougher second-order sound in each pipe, while the X (or any single-exhaust system) results in a higher fourth-order sound....."

And I found this in the Hedman Hedders catologue. " The tangentially siamesed crossover junction of Hedman's X-treme Exhasut Equalizer System, synchronizes the exhaust pulsed to eliminate firing order pressure differences between the right and left banks of the exhaust manifolds, or hedders. The firing order of all production V8's has one cylinder in each bank that will fire within 90 degrees of crankshaft rotation from another cylinder in the same bank. These two cylinders expel, nearly simultaneously into the same manifold system, and compete for limited exhasut volume. This causes a loss of power and poor fuel economy. Full length, 4 tube headers help separate these pulses. However, once the gasses reach the hedder collector, the two cylinders again fight for space in the exhaust pipe. Hedmans's X-treme equalizer system, splits the exhaust flow so the pressures on both banks will be equal and pulse free after the crossover, regardless of the RPM. The volumetric efficiency of your entire exhaust system is improved at all engine speeds, and that means more power out of the very same engine"

I guess I gave up the 60's muscle car sound, but the sound is smoother and not as loud, and I might have picked up a horsepower or two.

Bee Jay

 

That is what I was wondering, at least in terms of the sound difference you hear. I guess my question would be, had you gone with the X-pipe set up first/only, would the results have been the same in terms of sound? I am running straight duals, delta flow 50's, no interconnect pipe of any kind and it can get brutal inside the car. I love the sound outside the car and actually wish it were louder but I am afraid with the X-pipe, I will lose even more volume and snarl.

 

on a side note, i noticed you had a tubular trans cross member, where did you get that?

 

We need a new sound clip!

 

Nahh the optimum crossover pipe location on any vehicle with headers, is 18" behind the collectors. The only thing is, that in a C3 that's hard to do.

 

Bowtie Overdrive
http://www.bowtieoverdrives.com/index.shtml

Bee Jay

 

Take out the H pipe it will sound and run better

 

thanks for the info. too bad i have a th350, damn.

the exhaust looks great tho. good spot for the X.