I just had an epiphany.

I was thinking about exhast systems and designs and comparing cars to quads. Then I put 2 and 2 together and I may have come up with 4. Here is my reasoning:

In a multi cylinder engine, like a small block chevy (SBC), all cylinders fire at different times. Therefore each header pipe has an exhaust pulse at a different time. Lets number them like this.

(1) (2)
(3) (4)
(5) (6)
(7) (8)

When a pulse from (2) reaches the collector it helps "pull" the pulses from (4)(6) and (8) out of the engine. This is exhaust scavenging. If done correctly it will improve the performance and efficiency of the engine. The Raptor engine has two exhaust ports, and all of the pipes I remember seeing have pretty much equal length headpipes, so one may surmise that when the header tubes come together at the collector the same principal applies. But normally it does NOT.

In a single cylinder engine with dual exhaust ports, both ports are open and flowing at the same time. Both headpipes carry the same pulses, so if the headpipe lengths are equal, both pulses will be trying to enter the collector at the same time. I think this will cause turbulence and hurt flow.

So here is my breakthrough idea. Use staggered length headpipes to get the pulses to reach the collector at opposite times, so that the "scavenging" effect can be most powerful.

(1)
\
\
}----------
/
/
/
/
/
(2)

The pulse leaves cylinder 1 and 2 at the same time, but 1 gets there first. It helps "pull" 2 towards the collector, increasing exhaust speed. By the time 2 gets there the engine is firing again and it helps pull the new pulse from 1.

So there is my idea. Food for thought. Now someone test it out. Just remember me when you make your millions.

RR1

 

so your saying one of the headpipes should be longer from one of the port than another so they dont both realease at the same time? interesting [img]i/expressions/face-icon-small-cool.gif[/img]

 

Sounds like this guy is on to something and knows what hes talkin about

 

Is this what the LTE looney tunes raptor system does....I thought I heard somewhere that the pipes were of diffenent length....anyone know???[img]i/expressions/face-icon-small-confused.gif[/img]

 

Sound's like a good thought.[img]i/expressions/face-icon-small-smile.gif[/img]

 

I'm surpised none of the big ATV exhaust companies have not thought of this. Are all of the aftermarket exhausts equal length designs? I guess its time for you to do some cuttin and weldin!

 

No, all aftermarket exhausts arn't the same lenght but very close. It appears to me that this would work!! but think about it: about how much more power would you increase with this idea? this idea would pull 1 and 2 towards the collector faster but overall how much faster... this idea looks like it can work and maybe it can and bring a whole lots of power to the rappy!! someone call up the LTE looney tooned exhause company and ask them what there system does..

-CRUZ-

 

Tuned headers on a race car sound Awesome. I think you might be onto something. I am working on the same thing for my exhaust on my 1000. I'm running dual exhaust out each side, into a glasspack. When building the collector I was thinking same thing.

 

I think you guys have been drinking too much this sounds like a Bob and Doug Mackenzie skit. What do you think the engineers and technitions at aftermarket companies who have been in the business for decades haven't looked at header and exhaust r & d technology as far as altering convergence points. The reason the pipes are the same length is the pulse from one pipe will travel up the other the wrong direction if the convergence points are different.

 

Sorry to break it to you but your WRONG! It will not work the way you think.

Let me explain why.

Let me start with the V8 example. For best exhaust flow, you usually pair two pistons together that are 180 degrees out of phase. Meaning the one is on intake stroke and the other on exhaust. What happens inside the exhaust is that the two pulses will never compete for the same pipe diameter. The 180 degree pulses also causes a vacuum behind them, that help suck the exhaust gasses from the other piston. The best way to achieve this is to actually make the pipes cross each other like an "X". The "Y" connection works in a similar way, but not as great as the "X" connection.

Now to go further. It is possible to tune the pipes for better exhaust gas extraction. The principle works like this. When an exhaust valve open, a sound waves is generated inside the exhaust pipe. It runs from the exhaust valve all the way to the opening of the exhaust or header. When it reaches a muffler or an opening in the pipe, the sound waves generates another wave which travels back towards the exhaust valve. By tuning the pipe so that the sound waves reaches the exhaust port, bounces back and then the valve opens, will cause the sound wave to generate a vacume behind it, and it helps to pull the exhaust gases out. The sound wave can also push exhaust gas in front of it, again helping exhaust gasses left behind by other pistons.

The raptor does have two headers flowing into one, but it has a single piston. So no help form other pistons here.

Now, to explain further. A bigger diameter pipe does not mean it will flow more exhaust gasses. What actually happens is that if the pipe is too big, the exhaust gas loose velocity and the flow slows down. This causes less gas to flow. Make the pipe to small and it becomes a restriction. The aim is to get the right combination. You need the smallest diameter pipe that will not cause a restriction. If you get it right, the exhaust gas will maintain a higher velocity inside the pipe and the higher the velocity the quicker it gets out of the pipe.

Now, the raptor has two smaller primary pipes coming into a secondary bigger pipe. The two smaller pipes have much less diameter than the bigger pipe. This means the bigger pipe can outflow both the two smaller pipes. Also you will see that the pipes are running virtually parallel to each other when they go into the bigger pipe. This prevents the gases from making turbulence when they join together. They are flowing in the same direction and joining them together actually helps to align them further and it keeps them from making turbulence inside the pipe. It also helps the gas to maintain velocity. They don't compete with each other, but actually work together. It is a good thing to make them the exact same length. This ensures maximum velocity and flow.

More velocity, more flow, more power.

You can also now tune this exhaust pipe to use sound to help scavenge the exhaust gasses.

Now for the last bit of info.

The LTE exhaust system many people love, is going against all the rules of best flow and power.

1st they keep the exhaust pulse from joining together. This limits the gas velocity. Less velocity less power. They also don't use the same pipe length. This means they cannot use the tuned pipe principle. Since both pipes are not the same length, they don't generate the same frequency sound waves. This means they cannot work together to suck the exhaust gasses out of the cylinder. Each pipe for himself. All this adds up. Damn good looking pipes, don't get me wrong, and I am not here to try and bash the pipes, but they will never produce the same power as a single tuned pipe.

When it comes to exhaust pipes. bigger is NOT always better! Remember that.

It’s a damn fine art to make a good exhaust pipe and it takes time to get the right mix of pipe bend, diameter and length.