EXHAUST Theory can someone expain it to me..

The method I use to place an exhaust crossover is to lightly spray paint the exhaust pipes from the headers back about 18 inches. Just upstream of where the paint stops burning off is the best place to put the crossover.

 

hey scottybaccus,

thanks for the information and suggestions.

that was matching what I was thinking, but with two kids yammering away, thinking was VERY difficult.

not looking to dragrace, just cruise.......

thanks
dv

 

The first thing that comes to mind if you want a RAP noise , follow a school bus sometime. They have a muffler real close to the engine and about 30' of straight pipe therafter, when they let off on the loud pedal it gives off a nice Rap IMO

 

my head hurts

 

Corect me if I am wrong but the "smoke thing" is mostly with Flat Heads and Mopars.

 

Anyone ever seen a noticeable sound or tone difference between "H" and "X" pipes?

 

Yes, but hopefully it will serve as a catalyst for for further discussion.

 

Hmm ,, radial exhaust vs bias exhaust

 

Older thread, but definitely some good info.

 

Yes it's an "old thread".
Okay I have a Chrysler flathead 6, dual Carters 1 bbl B&Bs, tru split dual exhaust manifolds.
This set up is in a 1955 Fargo truck.
I cobbled together exhaust with 1 walker stock type huge oval muffler, and 1 walker huge chambered muffler off a motor home.
Not only doe this sound pretty quiet and lame, I really wonder how much power is being robbed from an already limited power source.
The tail pipes dump at the rear diff, pipes are 2 inch front to back.
What do I need to do, A) make it sound better, B) make the most power?

 

I love this stuff. I'm the kind of guy that thinks technical manuals are good reading.
I am probably more interested in the sound of my system, and peak performance is secondary. I grew up in the days of muscle cars where dual exhaust and turbo mufflers were the norm. Sadly, my age or something has me at a point where I can't tolerate the drone from inside the car with that type of setup, but I enjoy the sound from the outside. For me that healthy V-8 sound goes away when you add a crossover pipe...be it X or H. I guess my ears prefer the vintage sound an unbalanced system gives.
I love the deep-throated sound of a good sidepipe. Not a cheap add-on, but a real header sidepipe like the old Hooker corvette units, or a Cobra. My ears always perk when I hear one of these. What about them is different? Is it possible to have that kind of tone from a system hidden under the car?
Just by looking, I would guess that the side exit is important... you hear one side while the other is pointed away. Large tailpipe aft of the muffler seems to be another key feature, but what lives inside the pipe? Is it a long large-bore glasspack?

 

We found out on round track cars that would not allow headers that we would run 2inch head pipes into a merge collector into a single 3 inch pipe and it helped torque to get a heavy stock car up off the corners. Worked so well they outlawed it as a high performance part.

 

Sound is going to be mostly about the mufflers. Huge, stock type, mobile home (?!?) parts are going to be about quiet, unobtrusive motoring down the road. You'll need something else if you want a different sound from the system. What are you looking for?

Performance is about airflow through the system. Input (carbs, manifold, porting etc.) matters. Output (headers or manifolds, dual or single, H or X pipe, pipe diameter, length) you're trying to maximize airflow. Smaller pipe can help keep the velocity up. Bigger pipe slows it down. H or X helps one side pull from the other, evening out the flow.

From where you're at, unless somebody has a similar combo, you'll have to experiment with pipes until you're happy. Pick the mufflers first, probably. Then tune the pipe selection. Unless you're racing it, though, pipe changes probably won't yield much difference you'll notice.


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My 56 Chevy a warmed over 327, fender well headers, an "H" pipe and flow master 40 series mufflers with the pipes exiting below the rear bumper. I think the pipes on this car sound great. The only thing I can attribute the great sound to is the "H" pipe.

Gary

 

In my '32 Sedan (383 sbc) I run 1 5/8" shorty block huggers, a Summit X pipe, two Raptor turbo muffs and dual long straight pipes out the back (all 2 1/2").

Its kind of mello inside, but my daughter says it sounds like one of those hopped up 5.0 Fox body Mustangs coming down the road.

 

Thnax Guys for thoughts on this, my set up being an inline 6, with dual exhaust, just trying to get advice or a feel for correct pipe size, and that type of stuff.
I truly believe the big mufflers on it now are restrictive and robbing power, which it needs all it can get...

 

I had a 1967 Camaro with an inline 6 in high school. I took the transverse muffler off and used a turbo muffler under the floorboards in the traditional location and split the tail pipe into two and ran to the rear bumper. It sounded EXACTLY like someone had taken the transverse muffler off and used a turbo muffler under the floorboards in the traditional location and split the tail pipe into two and ran to the rear bumper.
Flash forward 43 years and I find myself dealing with another 6, but this time a V6. So the info I've gleaned from reading this post will hopefully allow me to come up with a better plan this time. I know I can't change the V6 "pulse", but I would definetly like to lower the tone.
Thanks

 

Smaller diameter pipes attenuate lower frequencies. If you want a lower tone use larger diameter pipes. "Glass packs" attenuate higher frequencies. Basalt (rock wool) attenuates better than fiberglass which attenuates much better than steel wool. Use glass packs to attenuate the high frequencies and the sound will seem lower. Large pipes plus lots of glass equals about as low as you can get. But... large pipes can also lead to drones and rap and other nastiness so as with most things it's give and take. General rule: Mufflers can only filter sound, they can't add it. If the low frequencies aren't there to begin with, nothing you bolt on will add them.

As for large mufflers adding restriction and robbing power - large mufflers usually exist so you can attenuate sound without adding a ton of restriction. In any case the tube sizes and flow paths in the muffler define how restrictive it is, the size doesn't. But it doesn't really matter anyway because...

IMHO most people put WAY too much thought into "restriction" as a power robber. It doesn't make nearly as much of a difference as many will have you think. Case in point - back in the day I flow tested a stock muffler on a high performance motorcycle and compared it to a typical aftermarket muffler. It was common thought that installing the aftermarket muffler and rejetting to suit might gain you something like 3% more peak power. Two things to know about that - I never heard how much power could be gained by rejtting the stock system to get rid of the EPA mandated crap, and the stock muffler had ten times the restriction of the aftermarket. Yep, 1/10 the restriction would lead to maybe 5% more power on a good day. Maybe. If you rejetted for it. And compared it to the stock jetting which was NOT optimized for peak power.

If you want to make power, spend your time and money on the intake side of things. Effects there are primary. Exhaust effects are secondary. And the most gain in your exhaust won't come from changing the restriction of the muffler, it will be from changing the flow dynamics of the system, from the port to the crossover. And what helps you get big dyno numbers may hurt your drivability. It's that give/take thing again.

One final point to ponder with this "restriction" thing. Most people say they want more power when in fact they want more torque. They want more low end, not top end. Restriction rises with the square of the flow, as in twice the flow means four times the restriction and 1/2 the flow means 1/4 the restriction (rough numbers). Ok, so you want low end, like what, 2000rpm? How much flow is there at 2000rpm vs 5000rpm. If you're already losing low end due to restriction at 2000rpm, you must be STRANGLED at 5000rpm. But go back to the bike example. 1/10 the restriction at max flow allows maybe 5% more power. The engine used as an example was putting out well over 100hp/liter with the stock "restrictive" muffler already. How much of a handicap is restriction again???

Bottom line, if we're not talking about your Bonneville LSR car, the chances of a non-restrictive muffler being the critical path to significant gains in anything but sound is pretty slim. IMHO. (which was formed over about 20 years of developing mufflers for OEMs)

 

If your into reading

 

I love this "show" on the Motortrend youtube channel. You'll recognize these guys, at least names, from HotRod/CarCraft. Here are the episodes dealing with exhaust "theory". Everything done in the dyno room. An episode is only like 15-20min.

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=azPKIjxmmdU

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=_PVXvHkr-Vs

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=fCio5K0WfHU

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=bXQ-cXeri1Y

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=Y7_lSU3D0jw

https://m.youtube.com/watch?list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE&v=rTlHEOE2Zp4





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Does anyone know a muffler manufacture that uses basalt in lieu of fiberglass or steel wool? I tried searching and it's not something they brag about.

 

The Europeans used to use it a lot more than the US makers. These days I only ever see it as a replacement material for repacking bike mufflers.

 

bttt