Straight Pipes.

i'm actually unsure about this modification. one thing that i'm quite sure of is that i have to take off the resonators so it went straight from the catalytic to the exhaust. am i right or wrong in this? anyone has done this to their cayman? i've seen so many 997 owners did this to their car and their exhaust sounds much better. is there any major brand that sell this pipes or is it better for me to just custom it? thank you.

If you do a search, you'll find that straight pipes will hurt your engine's power. If you just want more sound, why not do the "free" exhaust mod listed in the articles section?

tokz, I have the second version of the 9ff exhaust. It has both mufflers and a muffler bypass, so a straight exhaust (called their varotune). In the straight mode the exhaust goes right out from the cats. I like the straight sound much better since there is a resonance about 3000 rpm when routed through the mufflers. I think the 9ff mufflers are the same ones used without the cutout since they look identical, meaning there is nothing much inside to reduce the back pressure. I'm thinking about cutting open the mufflers and adding some sound baffles and a cross over pipe to the other side so, in the muffler mode, it will be quieter. Back pressure is no abject anymore since I can select the straight through mode.

I am having straight pipes made with resonators where the mufflers go, then the techart muffler between.

you don't wanna do straight pipe.. tubi = no resonator + fabspeed header (no cat) = straight pipe. your car needs back pressure....

I tried this - nor recommended. Resonance is horrific, peculiar torque curve and wasted money!! I spent a lot of money figuring out that cats in the headers are essential although the 997 characteristic is the opposite...

What about removing the second set of cats in the mufflers and gutting things out of the muffler cans and then piecing it all back together? What effect will this have on the engine if any and what would be advantages/disadvantages of doing this particular mod? (to be done on spare stock muffler system) Seems a lot of tuners at least here in Germany use stock sets of mufflers but then convert them into "race" or "loud sound" mufflers by doing what I mentioned above or at the most adding 100 cell cats all for insane amounts of money. Forgot to mention that I am not after power just sound (rumble).

trust me... you will regret this... loss of power..

Loss in power in what way? What would be the main loss of power (which config)? Would creating a bypass pipe be best and get me the results i want? TIA

just buy the GHL or SuperSprint systems....not too much $$ and sound very mean (rumble)

I put a straight pipe on my 944 Turbo once to get an idea how loud it might get if I added a Borla XR-1 system. I drove around with it for over a week. I couldn't believe the difference in feel. It felt like the brakes were dragging or something. There was a very noticable loss of power. This was reaffirmed again when I put the stock exhaust back on and the car felt like an animal (because I got used to the reduced power of the straight pipe).

gator, That would be opposite of most everyone with a turbo car. The least amount of backpressure post turbo is best and worth good power. I have had several turbo cars and all of them have benefited from a low restriction exhaust. On a NA car, things get more tricky since scaveging effects come into play as do the diameter of the pipes for the exhaust pulses. Bigger and open are not always best. I'm curious what Mantis runs on their race Cayman...looks like headers and some small generic mufflers...nothing too fancy looking for sure. Wonder if it gained power?

Yes, that's what I was expecting too. But was blown away at what I could feel. This all happened because I bought a bolt on Borla cat back system and was sure that the car was slower and had lost power with it on the car. I did several tests, swapping the Borla back and forth with the factory exhaust and it was undeniable. The stock exhaust was quieter but definitely more powerful. I called Borla and they said the only thing that might outperform my stock exhaust was their 12" XR-1 racing baffle, but they said it would be way too loud for street. I told them, 'Let me be the judge of that' and whipped up a straight pipe to see just how loud the car might get. Believe it or not, the car wasn't that loud, except under full throttle when the waist gate opened up. Otherwise, the turbo was a nice baffle. I went with the XR-1 and was very pleased. Good sound, great performance (just a little droney at some RPMs). But for some strange reason, contrary to most Turbo nomenclature, my car definitely was stronger with the XR-1 or stock exhaust than with the straight pipe.

That thing sounds like a V-8, not like a B-6. Weird.

Exhaust back pressure is a myth. If you google for it you will see what I mean. The theory is that you need a properly designed system that maximize exhuast flow velocity, cross flow and corresponsding engine fuel maping. I think a stright pipe only will be too loud and possibly loose power. BTW I think the two muffler muffler act as a cross over for maximum power. That is why there is a tube that join between the two halves.