Lets talk exhaust systems!

by JiMi_DRiX Sun Nov 18, 2012 3:59 pm

So one of the next things on my list is to have the exhaust on my 76 redone from the headers, back. It currently has long tube, ceramic Hooker headers, down into 2.5in pipe, 2 cats, and 2 Flowmaster 40's out the back. I plan on keeping the headers, but I want to do something different with the pipe. I would LIKE to eliminate the cats, go X pipe, but I am unsure on mufflers. I want it to sound mean, but I like that mean "flutter" to the exhaust, as opposed to just the "roar", maybe that is due to the cats choking off my exhaust?

So what do some of you guys have on your cars? Anyone with X or H pipes? How do they fit and/or get in the way when working underneath? Any good HQ sound clips/video would also be very cool to check out. Thanks guys!

by Brainstain Sun Nov 18, 2012 7:40 pm

This is all theory, but I had planned on making my X pipe on my wagon up inside the rear spring/shock tray basically right behind and above the diff cover but tucked up close to the frame. Your situation may be different because my car is lowered, but that was really the only place I could see it not being in the way.

by 77mali Sun Nov 18, 2012 9:33 pm

Maybe someone else can chime in on this too but I've always heard that it's best to run the two sides independently of each other all the way back. I know a lot of people use X/H pipes but I'm not really sure what benefits they bring.

Personally I'm considering running a custom 3" single exhaust (just to be different) which would require a Y type connection for the headers with a thrush or magnaflow muffler.

The Cam also has a lot to do with the sound you hear.

by Brainstain Sun Nov 18, 2012 11:11 pm

I found this on Nastyz28.com

X-pipe helps with cross-bank scavenging and smoothing of individual exhaust pulses (like a floodgate of sorts). They almost always make more power and torque through the midrange than straight pipes of the same size (assuming same muffler and tail pipes).

X-pipes have consistently shown an additional 10 HP or so more than true dual exh. It allows more efficient scavenging and reduces retrograde pressure waves from causing exh. gas reversion. They also drop the sound level a notch, also. An H pipe does the same thing, but not as efficiently and is more difficult to properly place.

The thread also said that it made the car a little quieter at idle and a tad more raspy (Which personally I like). Also it said the closer to the collectors that you have the X/H the better. Maybe this helps with the decision to use one or not even if I didn't answer your original question.

by 77mali Sun Nov 18, 2012 11:46 pm

Interesting read

http://www.surefloexhaust.com.au/xpipe.htm

http://www.pypesexhaust.com/xpipes.html

Here's a system fro Pypes
http://www.pypesexhaust.com/sys-chevelle.html

by Joe73 Mon Nov 19, 2012 11:15 am

I'd pass on the 3" exhaust unless you truly have above 500 hp. Otherwise you will lose some low end power. From what I've read, the X pipe performs better than the H pipe. I'm still undecided whether I'll go X or straight duals on my chevelle. BTW, I believe summitracing on EBAY is selling also selling the PYPES system with NO H or X pipe if you like. Just FYI.

by BlackChevelleSS Mon Nov 19, 2012 11:43 am

Yes X pipes will make it very raspy and raspy makes it louder, it will sound similar to mustangs. A Single pipe out the back is good for flow as it uses the same concept as an X pipe does. Its Another thing to consider. My Latest exhaust on my V8 Swap s10 was 2-1/2" off the headers into a Flowmaster Y with 3" out to a Delta Flow 50 series and 3" over the axle dumped.
Sounds good and is loud when your on it and quiet at cruising. No nasty rasp to it at all.

by jerry46765 Mon Nov 19, 2012 6:44 pm

When you connect the duals with a crossover, exhaust pulsations become common. The type of crossover and the location depends greatly on the engine, packaging limitations of your vehicle, and mufflers used.

We used to race in a series where we were teched for sound level at various engine speeds. We ended up spending lots of time and money on exhaust to get power and barely meet sound limits. It's tough to generalize because so many parameters vary from vehicle to vehicle and with different engines.

Duals with no crossover; dampened mid range torque, good peak hp, but loud.
Duals with x pipe; improved mid range torque but limited peak hp, reasonable sound level.
Duals with H-pipe (depends on location in exhaust & size); improved mid range (over no cross) but not as good as x pipe, but better peak hp, with better sound level than x pipe.

We ended up running an H-pipe, and worked with testing different locations for the H-pipe and changed the size to make more mid-range while maintaining peak hp.

Muffler wasn't as critical, but some were definitely better than others for power vs. sound which another story all in itself.

For a street car, I can't believe you will feel any seat of the pants power difference between x, h, or no crossover, but you will definitely hear the difference.

Exhaust size is strictly based on the power you are making; big power should have big pipes.

Thanks -

by 77mali Mon Nov 19, 2012 7:03 pm

That was an excellent explanation! Much better than all the Technical mumbo-jumbo from some of the manufacturers.

by 77mali Mon Nov 19, 2012 7:16 pm

Joe73 wrote:I'd pass on the 3" exhaust unless you truly have above 500 hp. Otherwise you will lose some low end power. From what I've read, the X pipe performs better than the H pipe. I'm still undecided whether I'll go X or straight duals on my chevelle. BTW, I believe summitracing on EBAY is selling also selling the PYPES system with NO H or X pipe if you like. Just FYI.

Thanks Joe

Maybe I'll keep what I have for now & see how it works out with the new engine set up (it's free).

by JiMi_DRiX Fri Nov 23, 2012 2:05 pm

2.5 is perfect, I wouldnt ever go above that, I dont plan on changing the pipe size. Can anyone think of any reason why that Pypes kit for the 77 chevelle WOULDNT fit on my Monte? Maybe I can do this myself instead of going to a shop.

by 77mali Fri Nov 23, 2012 3:01 pm

You may need to tweak it by cutting. Call them up- but I think it's the same frame as a Malibu/Chevelle, right?

by Joe73 Fri Nov 23, 2012 4:02 pm

chevelle uses a 112" wheelbase frame. El Camino, Monte and 4 door cars use the 116" wheelbase.

by Checyxtc Mon Dec 03, 2012 11:51 pm

I just built a nasty 468 with 2.5 ceramic coated headers into 3" pipes out through Flowmaster 50's out over the axle and dumped out behind the rear wheels. You can check out the sound on youtube if you like, just type in 74 Chevelle 468...mine should be the first one you see. I do get a bit of drone and was considering the H pipe but I'm pretty happy with it the way is is so far....LOUD-N-PROUD Smile

by vegadan Mon Dec 17, 2012 11:47 pm

I bought a system for my 73 GA with stock exhaust manifolds from this seller:

http://www.ebay.com/itm/1973-1974-PONTIAC-GRAND-PRIX-DUAL-EXHAUST-SYSTEM-ALUMINIZED-/181047130804?hash=item2a273ffab4&item=181047130804&pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr

It's a little too quiet, but the seller was willing to change the muffles if I wanted. Or, he would have sold me just the pipes if I wanted. Also, the system he advertised was a 2" but he provided a 2 1/4" system for extra charge. The system fit real nice. The first set of tail pipes weren't bent correctly. I sent him an email with some pictures, and when I called him and discussed it with him, he sent me new tail pipes at his expense. Once I got the correct tail pipes, everything bolted right up. I have heard that the Pypes systems need some work for our cars (earlier model years apparently fit much better) so take this for what its worth.

Dan

by pila Tue Dec 18, 2012 11:14 pm

I just emailed the Pypes place, to ask about stainless tail pipes for my '75 Elco project. Since it's stainless down pipes & mufflers, I want tail pipes that wont rust. No room for headers on my engine, so stock ported manifolds are on it.

by Bruisr Wed Dec 19, 2012 4:55 am

How come you have no room for headers?

by 77mali Wed Dec 19, 2012 6:51 am

He has a big & bad a$$ Caddy motor in his Elco. (500+ ci?)

by pila Wed Dec 19, 2012 9:52 am

Yeah, it's a tight fit, and there are no bolt-on headers to fit it. Here's the right side manifold, and I had to trim the front suspension bolt a bit for clearance.
Lets talk exhaust systems! P1010980

It's 507 inches with a +.030 bore.
It's intended to be a daily driver, so I don't want plain steel exhaust. Lots of salt on the roads here in winter.

The Caddy guys tell me that 2.5 inch pipes are the way to go on my set-up, so that's my direction.

by Bruisr Wed Dec 19, 2012 5:58 pm

Wow! thats friggin Awesome! Do you have any threads showing or detailing your 507?

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