All thoughs looking at exhausts Here you go!!!I found some good info

[Snipe]

Alright gotta remember this is a bit older info, but since mostly the quads havent changed im sure it still holds true.

They dont include some things like Loonytunez exhaust and such as they were not invented yet.

But this site gives dyno readouts and test results for the best pipe's and slipons weight and looks like they did there homework.

[BEAVER.989]

Good info, I've seen that.

I wish somebody would do a new shootout with what's currently on the market, though. Half of that stuff is no longer around, but for everyone missing, there is someone new to replace them...

[Snipe]

The only ones I see on there that are getting harder to find but not impossible is the white brothers. I just got really lucky on mine.

[matt14c]

Would never trust a magazine review on any product. Magazines are supported by advertising dollars not the $5 you pay for it. If some company is paying thousands and maybe hundreds of thousands more to a publishing company they would have to be stupid to bash there product and it wont happen!!! I know awhile back when the 400's were really popular and seemed like everyone was putting an exhaust on them. Dirt wheels or someone did a review and didnt even include the large race company brands like sparks, lrd, CT and im sure others. The mags are extremely biased. Plus there is tons of factors that go into making an exhaust the best or right one for you.

Just on the exhaust subject engines do not need backpressure and backpressure is not a good thing because it puts force on the exhaust gases trying to come out and your exhaust gases will not flow fast enough taking power away. So the more free flowing and open exhaust design the more power you will have. Headers are where you change the powerband but for the muffler portion go with the most open design or straight through as they would call it for cars.

[Snipe]

Alright both of these posts are not true.

Yes I can see how it would be biased if it was owned by 1 company. These are just dyno readouts of what happened when running it. Take it for it is. Not forcing it down your throat take it or leave it.

Back pressure is very important. To much back pressure you will have over heating issues. Not enough back pressure you can cause valve damage. That is why all mufflers in some fashion have holes on the inside to run the air through the packing. to some extent a straight pipe is alright but running a true straight on a ATV is not reccomended.

[dariusld]

Originally posted by Snipe
to some extent a straight pipe is alright but running a true straight on a ATV is not reccomended.

Not reccomended by who.... You?

[Snipe]

No not by me I never said that.

Gotta love stupid little kids trying to start fights on the internet I laugh at you HAHAHAHAHA......no wait had to get a breath HAHAHAHAHAHAHA ok.

No I never said it was by me. but I promise you, you do have to keep back pressures right if not you will have problems if this wasnt the case and the best thing to do you think every racer out there would simply just take the exuast off all together but since ya dont see that happening EVER I would suggest in my (PROFESIONAL) opinion keep a good exhaust kit with a slipon of some kind on it.

But by all means if ya wanna take your exhaust off an run it go for it.

But back on subject this was just posted as there has been lots of ppl asking questions about exhaust lately this was a good read so I posted it. so if ya wanna jump down anyone's throat I suggest ya emailing the ppl who actually made the magazine. Until then I would keep my kiddy mouth shut and just enjoy the fact that someone took the time out of there day to try and help others including self centered pricks like you out.

But to all others enjoy the info in the link above. :devil:

[dariusld]

I know what you are trying to say, even if its wrong, but you are not very clear in what it is. Just look at my quote above, you don't see the flaws in it? Then your response just makes you look even worse.

Originally posted by Snipe
Alright both of these posts are not true.

Yes I can see how it would be biased if it was owned by 1 company. These are just dyno readouts of what happened when running it. Take it for it is. Not forcing it down your throat take it or leave it.

Back pressure is very important. To much back pressure you will have over heating issues. Not enough back pressure you can cause valve damage. That is why all mufflers in some fashion have holes on the inside to run the air through the packing. to some extent a straight pipe is alright but running a true straight on a ATV is not reccomended.

thats not true no valve damage will be done with a open flowing design. yes you want a bend for your power curve but after that you dont need anything else. seriously look it up backpressure is bad for motors

[Snipe]

Q. Why do engines need backpressure? Won’t a larger exhaust pipe give my 944’s naturally aspirated engine more power?

A. I’ve always understood that you want to keep the exhaust gases moving, even once you get them out of the cylinder. One thing that will cause the gas to slow down is a sudden decrease in temperature, which is one reason why auto makers don’t try to cool the exhaust manifold. The other thing that can cause a decrease in flow velocity is rapid expansion and turbulence, like going from a small passage (like the exhaust port in the head) to a 6-inch pipe. A smaller-diameter pipe geometry will tend to keep the flow rate up, but it will also lose heat more quickly (less exhaust gas per linear inch of pipe). However, a large pipe will slow the velocity due to expansion. Worse still, the exhaust is constantly cooling from the moment it leaves the cylinder, meaning it’s getting denser and slower. See the problem here? It’s all about compromises. The proper pipe size is going to be influenced by the flow rate (volume rate, which is related to RPM and engine displacement), exhaust velocity (again related to RPM), exhaust temperature (constantly changing, and as high as 2,000&Mac251;F, if I remember right), and undoubtedly an array of other factors. All of this is dependent on the application: is this a street car, a race car, or something in between? Where will the engine spend most of its time? Idle, full throttle, part throttle?

I’ve also heard the thing about back pressure, but I believe that they’re really talking about flow velocities. That is, if you can keep the exhaust gases moving in the exhaust pipe, they will cause a small reduced-pressure area behind the closed exhaust valve, in the exhaust. This happens because the gases have momentum. They move away from the valve, creating a localized reduction in pressure. When the exhaust valve opens, this reduced-pressure zone will help evacuate the burnt gases from the cylinder. Or so the theory goes, as I understand it (two disclaimers there).

The bottom line is that Porsche has probably already considered all this and other factors when sizing the exhaust on the 944. Unless you’re significantly increasing the flow rate, you’re likely to cause more harm than good.

Its about a porche but it still applies to any compustion engine from a lawn mower to a freaking tanker ship.