What are the Pro's and Con's in running a straight pipe with a 996? Performance? Sound? Anyone here run straight pipes? Any issues with local law Enforcement? Fairly cheap mod, but want to hear from your experience.. Thanks

 

It will sound like crap under light load, moderate load, really everything but full throttle.

 

^^^^This, but Everybody has Different taste!

 

A friend of mine has the best sounding 996 I have ever heard, and I have heard many. He installed the muffler by-pass pipe with gutted cats and SS headers , and even with double-disk CC inserts the car was too load and did not have a good timbre. BUT he installed some 200 cell cats with the X-pipe and muffler by-pass and CC inserts and the car sounds amazing!!! Its got a very exotic and tuned sound all through the RPMs (especially 5k-7.5k)and while it is VERY load under full throttle , but can be driven very quietly if you use a lot of restraint. He has had it installed almost a year about 6k miles and hasn't got a ticket yet, but I am surprised that he hasn't slipped up and been under too much throttle and got the Law's attention yet. I have not installed this on mine because mine is a tip and would not sound the same with the wider gear spacing and soft shifts. SO I went with a more intense intake sound with my custom cold air intake and sound symposer retrofit.

 

i have a video of my car i am working on editing before figuring out how to up load it . but... i run stainless headers; custom made X-pipe with 100 cell cats, uses all four o-2 sensors in factory positions; to straight out ends both sides. no mufflers. before i used muffler by-pass pipes with stock cats and sounded OK but defiantly choked at high RPM. now sounds good at low RPM until 4000 when cam change then sounds very F1-ish. more to come.........

 

Yes please post when completed! Thanks..

 

A friend of mine said I would encounter engine issues if I ran straight pipes. Is this true? He said something about the back pressure and causing issues? Thanks..

 

It is certainly possible. The cam and cam timing and other things in the flow of air into and out of the engine is based on the back pressure arising from the stock exhaust system.

Reduce back pressure and the result is the engine could breath less efficiently.

I know it seems contrary that reduced back pressure could do this but the air flow through the engine from the very start of the intake system to the exhaust outlets is very complicated and there are complex interactions that engineers and scientists spend their entire careers studying/understanding.

The only way to be sure that I know of is to do a before and after dyno test to have the before and after HP and torque numbers and curves.

From this then one can see what if any decrease (or increase) in HP/torque there is and at what RPMs.

What you might find is low/mid-range HP/torque is down -- and this is where the engine spends the bulk of its time -- while top end HP/torque is up although probably not very much.

But without the before and after dyno runs there's no way of knowing.

 

Just wanted to say thank you for taking the time to write up a response to my question. Really appreciate it!

 

Porschetech3 - what is your custom cold air intake?

Thank You

 

Custom cold air intake with sound symposer retrofit including K&N filter and aluminum heat shield





Custom cold air intake with sound symposer retrofit including K&N filter with Lexan heat shield

You can see the sound symposer in the tube off the left side of aluminum MAF housing directly under oil fill pipe

 

Very nice!

Thank You

 

cWade thankx...The sound symposer has a remote control to turn it on and off. With it off it sounds just like all other cold air intakes (witch is a very good sound). but with the sound symposer ON it has another level.

 

Don't do it. I've ran the Fabspeed Muffler bypass with stock cats and it's still way to loud. Not pleasant to drive and doesn't feel any faster just louder. I have the Fabspeed Supercups on the car now and it sounds amazing, but also a little too loud for me. I'd be willing to sell them if anyones interested. There in great shape. T

 

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