180 degree headers?

[Burninrock24]

How many times do I have to say in one thread that I'm not in it for the performance gains. I realize that there are 20 other mods that I could do that would be more effective at adding power, but I just want the 180 degree sound... If I was interested in racing I wouldn't have bought a 2V NPI Convertible.

Also, I realize that its not the same comparing a C5, but if you've ever been under one, there's even less room. Biggest difference is that the transmission is in the rear of the car.

 

[MustangChris]

yea guys. If he were looking solely for performance he would have bought a 2013 shelby. lol.


but adder has a fantastic point. these will never fit with a OEM k member. plan on going tubular while you're in there.

heres what LTs look like:

dont listen to the flame-throwers Get that shit done! Especially if you have a sponsor willing to do it. lol.

 

[Musturd]

Don't like the idea and good luck with ur stock k member and vert k member brace

 

[MustangChris]

oh yea. the x-brace.... lol.


maybe do 180* headers over the top of the engine isntead.



so... you'll need sub frame connectors and a tubular k member.

 

[OnyxCobra]

I don't understand doing this not for performance, isn't that the whole point of them in the first place? What happens when you get it all done and it sounds the same?

 

[Burninrock24]

Don't like the idea and good luck with ur stock k member and vert k member brace

ok

oh yea. the x-brace.... lol.


maybe do 180* headers over the top of the engine isntead.



so... you'll need sub frame connectors and a tubular k member.

Believe it or not, I've seen people doing them around the serpentine belt and everything. Just insane! I've been doing a bit of reading and it looks like tuned length long tubes are tuned to the 3rd harmonic. [Harmonic meaning when the pipe is in a happy place with the pulses of the exhaust, which helps it just flow and scavenge.] And usually these long tubes are like 25-35 inches for our cars.

But there's a second harmonic that's some 50-60 inches (haven't done the exact calculation what it would be on my motor) that would allow me to run it like long tubes coming out of the engine bay, and be able to cross them over a little more near where the X pipe crosses. The issue is that with running headers that long, the CFM is limited at higher RPMs, so I would have to step them meaning expanding them to a larger diameter after a certain length. There's calculations for all this, but I just haven't done them yet.

TL;DR: I can build (extra)long tube headers and they should still work fine and not have to snake around in the engine bay since I don't need a midpipe anymore.

I don't understand doing this not for performance, isn't that the whole point of them in the first place? What happens when you get it all done and it sounds the same?

It's purely to be unique and for the sound. If I do it right, I am 99% positive it will sound like a flat plane V8. I still have a couple knots in my understanding of them to iron out, but I'm asking around on physics forums and such to get the harmonic tuning figured out.

Here's another video, I don't like the mufflers the guy has on since they sound too raspy. But I've never every heard a Chevy 350 sound like this: http://www.youtube.com/watch?v=o9Ye8fFH90w

 

[Musturd]

Believe it or not the whole idea stinks ....

 

[MustangChris]

common now, Musturd... its not your ride. its not your money. its not your sponsor. I havent been this excited about a customization on this site in a LONG time....

 

[Burninrock24]

common now, Musturd... its not your ride. its not your money. its not your sponsor. I havent been this excited about a customization on this site in a LONG time....

I expected some flaming (a lot more than I got actually), so it doesn't bother me, plus Musturd has just been pissy with lots of random people in threads that I've seen lately, so it's no skin off my back.

I'm pretty excited too, I still have a lot of reading to do before I tackle it. I want to do it once and do it right, so I'm getting some books from the library transferred to my local one to catch up on reading, and in the meantime I'm reading up about the harmonic tuning.

I know that Ferrari specifically tunes their motors to 3rd and 6th harmonics. But I don't know if thats the headers, the tail pipes, or the intake manifold. Because all three can be tuned to a certain harmonic order.

It's all a little intimidating, but I'm excited to learn and I'll for sure post updates as I get more info! As of now, I have to work on getting more camber in my track car, and then I'm off the fleet farm to find some flexible tubing that will allow me to make header-like forms for preliminary test fitting!

Here's the software that I'll most likely be using. The physics forums say it's the most accurate for your buck. So I'm down with that! http://hotrodenginetech.com/pipemax_header_design_software/

 

[ster302]

It would be cool, mostly because its different. Is there that much performance to gain from this? Or is it mostly sound? I don't know if I would want to try to work where any of those pipes crossover.

 

[Burninrock24]

It would be cool, mostly because its different. Is there that much performance to gain from this? Or is it mostly sound? I don't know if I would want to try to work where any of those pipes crossover.

Well there is definitely performance to be gained in the sense that I'm running stock manifolds right now which are trash. I will most likely be having to run longer than optimal primary lengths in order to get it all to fit, so unless I step the exhaust (meaning increase the pipe diameter before I merge all headers into one) then I will lose some power up top compared to just going with long tube headers. But I should still ultimately gain power across the board.

What these headers gain from is that the primary pipes connected are 180 degrees away from eachother in the firing order. Meaning when one is on the intake stroke, the other is on the exhaust stroke so that there is constant flow which helps with scavenging. Which is kindof what an X pipe helps with, but when done in the header the gases are still hot, expansive, and moving fast, so the effect is amplified.

And if all else fails and no gains are seen, you have pulses firing consistiently 180 degrees from eachother in each exhaust outlet so you get a higher pitched sound.

 

[OnyxCobra]

What these headers gain from is that the primary pipes connected are 180 degrees away from eachother in the firing order. Meaning when one is on the intake stroke, the other is on the exhaust stroke so that there is constant flow which helps with scavenging.

That's pretty cool. I was thinking that would be the benefit over regular long tubes but i didn't take the time to check the firing order, but if it blends it so that you get perfect 1-2-3-4 out each side in order I could see how that could give you a different sound.

 

[Burninrock24]

That's pretty cool. I was thinking that would be the benefit over regular long tubes but i didn't take the time to check the firing order, but if it blends it so that you get perfect 1-2-3-4 out each side in order I could see how that could give you a different sound.

Yep! And Ferraris have that sound naturally with manifolds because they have flat-plane 180 degree crankshafts. So each cylinder bank of the V8 is firing how I just described. The issue about a 180* crank is that this isn't nice on the motor, which is why they usually aren't a very large displacement.

Which is why the GT40 with 180 degree headers was such a great combo in LeMans, because it had the smooth(er)ness of the 90* crank, but the exhaust capabilities of the flat planed Ferraris. It's actually really interesting!

If I get ambitious and room-privided, I can get the pipes to arrange so they will fire in a circular pattern and help exhaust flow that way too. But getting them arranged in the first place is my #1 priority.

 

[ster302]

Well there is definitely performance to be gained in the sense that I'm running stock manifolds right now which are trash. I will most likely be having to run longer than optimal primary lengths in order to get it all to fit, so unless I step the exhaust (meaning increase the pipe diameter before I merge all headers into one) then I will lose some power up top compared to just going with long tube headers. But I should still ultimately gain power across the board.

What these headers gain from is that the primary pipes connected are 180 degrees away from eachother in the firing order. Meaning when one is on the intake stroke, the other is on the exhaust stroke so that there is constant flow which helps with scavenging. Which is kindof what an X pipe helps with, but when done in the header the gases are still hot, expansive, and moving fast, so the effect is amplified.

And if all else fails and no gains are seen, you have pulses firing consistiently 180 degrees from eachother in each exhaust outlet so you get a higher pitched sound.

What about theses headers vs. off-the-shelf long tubes? I'm just curious on the differences in hp/tq numbers, especially where it changes in the rpm band. The sound change would definitely be different.

 

[ttocs]

The pantera sounds cool of course but all the chevy clips I found(or you provided) sounded like an import trying to be cool too me. Not sure what it was other then I didn't like the sound myself but I can't help but be curious what the final design would look like and actually sound like.

 

[Burninrock24]

What about theses headers vs. off-the-shelf long tubes? I'm just curious on the differences in hp/tq numbers, especially where it changes in the rpm band. The sound change would definitely be different.

Well in a fair competition, I think they long tubes would perform better with the design I will be having to make mine into. There are lots of things that factor into making power, length of the headers, diameter of the primaries, length of the collectors, diameter of the collectors, arrangement of the collectors, whether or not each primary is equal length or not, if the pipes are stepped or not. So the better engineered long tubes like SLP or Kooks pretty much optimize the power available for our cars. They have the proper sizes and lengths of everything I mentioned above.

I on the other hand will pretty much be forced to run much longer primaries than the long tube headers, which helps torque but hurts HP a bit because the smaller diameter (versus dumping into a midpipe earlier). But some of that can be alleviated by stepping the pipes.

But really the most power comes from the pipe diameter off the head. So power numbers should be pretty close.

Here's a great article. It's from a Honda forum, but it would be ignorant to not learn from it. It's great info. There's also some good reading on it in text if you're into the more mathematical aspects of it, I could reference you a book or two.

http://www.team-integra.net/forum/b...ader-exhaust-design-effects-engine-power.html

The pantera sounds cool of course but all the chevy clips I found(or you provided) sounded like an import trying to be cool too me. Not sure what it was other then I didn't like the sound myself but I can't help but be curious what the final design would look like and actually sound like.

Yeah I wish I could find a 4.6. But I have to imagine the old Chevy small block ones had something pretty different from the others, because the Pantera, GT40, and Corvette all sounded good and relatively the same. But it's not much to compare I know. I'm fairly confident it will sound nice.

 

[Burninrock24]

Quick update, talked to another Mech. Eng. Student today who builds engines for an FSAE team, apparently tuning for harmonics isn't as important on the exhaust side of things because temperature gradients make it hard to account for. (Where as intake tuning is with a relatively constant temperature that sound travels through rather uniformly.)

So this is better news, it means I can be less concerned with primary length and just making sure they are *equal length* but resonance tuning is still in my mind.

 

[hondarocks61]

DAT SOUND

http://www.youtube.com/watch?v=ZoAPfJ4Rkbs

Please do this....

 

[MustangChris]

whats the word?

 

[boston2k4]

This is different for sure and i can see it working.

but on the flipside i see headaches ahead!
they do have those twinturbo kits that run all sorts of hot pipes right where theses headers would meet. so thats a good thing!

now i will say that without a kmember your really limiting you room. Doesnt mean its impossible just alot harder
i think it would sound amazing and flow great. put me down for a set if you get it ironed out man i like weird stuff!