Some aftermarket exausts have two rear silencers - one for each engine bank

Where as others have one larger silencer where the pipes seem to cross

What are peoples thoughts regarding these?
Is one design meant to be superior in comparison to the other?

 

And what gives different exhausts their different sounds?

Is the construction inside the mufflers different?
Are differnet materials used inside them?

 

As well as the normal aftermarket exhausts we see, with either one large centre silencer, or one silencer per bank, I have seen another kind of design

This design looks like it could be more efficient as the exhaust gases remain in the same pipe as they make their way through the exhaust - the obvious downside to this system is the ubend

The other systems seem to have the gases flow into the muffler and then either run through baffles, or through different chambers before exiting the other end

The exhaust pictured does not do that as it is made up of two lots of straight through mufflers for each bank

Does anyone else think this kind of system with straight through silencers could be more efficient than the baffle/chamber typre offerings?

(couple of pictures from Dan's site)

 

Ant_8u,

Here is a little information you may find helpful. The SpeedTech 996 series and 997 series mufflers/exhausts are a cannister design, similar your second picture. Although it appears there would be baffles "inside", there are no baffles in any Speedtech exhaust. They are all designed in a method known as "straight through" design, which is how we develop increased power over the factory systems. The exhaust pipe transitions to a perforated pipe inside the muffler, but remains in one continuous length from beginning to end. On our 996TT and 997TT exhaust, in effect, you have straight pipes with a catalytic converter and a method to attenuate some of the sound, as the noise passes through the system (they have a curve inside the cannister, so technically they are not straight, but the exhaust flow is straight through with no blockage, hence the "straight through" design).

To envision a "straight through design" exhaust better, picture this: If you were to hold a Speedtech exhaust vertically and place a ball in the end of the exhaust, it will quickly roll right to the catalytic converter in a direct path through the pipe with no detours, baffles, etc. We find this design more efficient than the cross pipe, linked pipe, baffled chamber or other designs, which can cause turbulence and interfere with flow.

SpeedTech 996TT Exhaust

 

Thanks John - nice explination, I think i've got it

Your systems are basically straight through pipes that incorporate a Ubend inside the silencer?

 

Yes, in our case that is correct. Not all cannister designs made this way, though - you must verify it is a straight through design, if that is what you desire...straight through design enables the most power.

 

Straight through designs are less restrictive but are still dependent on the type of cats that are in the system. A straight through design with 300 cell cats will not flow like one with 100 cell cats. If you only care about the sound then the cats make no difference. If performance is your main concern, then 100 cell cats should be important to you.

 

John - Am i right in saying your system is pretty much the same as the bottom picture in post number 3?

But, where as that system has two mufflers per side, yours has one
I assume this helps to keep the cost of manufacturing your system down?

BTW - Your systems are amazing value

Are you able to supply systems with 100 Cell cats?

 

Yes,

Ours would flow much like the third picture down, as the pipe design is basically the same. Sorry, we do not offer a 100 cell cat design, but our 200 cell exhaust makes about 50 HP on a mildly modded 996TT - I have seen a few popular 100 cell cat exhausts make less power.

 

Thanks John - very helpful

I've just seen the SpeedTech video on YouTube
Sounds good too me!!!

 

Here is another, newer one...it's slow loading due to size, but has some good footage...

http://www.speedtechexhausts.com/Spe...DIX%20V2.5.wmv

 

Thanks John - loading it now

What's the reasoning for choosing 200 cats?

 

I have this and I put down almost 1000 rwhp... 3 inch pipe with race mufflers period...
Not too much engineering LOL
My close friend has tested a few Expensive exhausts ($4k to 5K) and he actually lost power on the dyno... all that on a 600+ rwhp set up.... not going to mention names but you guys would be surprised....

 

where's the mufflers?

 

Mark - Is your system catless? Is that where the mufflers are?
That looks crazy!