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-   -   Pro's Vs Con's in running straight pipes (https://www.6speedonline.com/forums/996/384328-pros-vs-cons-running-straight-pipes.html)

911C4S Feb 16, 2016 08:59 PM

Pro's Vs Con's in running straight pipes
 
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

WearyMicrobe Feb 16, 2016 09:15 PM

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

johnnyreb Feb 16, 2016 10:08 PM


Originally Posted by WearyMicrobe (Post 4473724)
It will sound like crap under light load, moderate load, really everything but full throttle.

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

Porschetech3 Feb 17, 2016 04:45 PM

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.

turbogts Feb 17, 2016 05:34 PM

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.........

911C4S Feb 18, 2016 03:43 PM


Originally Posted by turbogts (Post 4474097)
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..

911C4S Feb 23, 2016 07:47 PM

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..

Macster Feb 24, 2016 01:34 AM


Originally Posted by 911C4S (Post 4476915)
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.

911C4S Feb 24, 2016 09:16 AM


Originally Posted by Macster (Post 4477012)
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!

cWade Feb 24, 2016 02:08 PM

Porschetech3 - what is your custom cold air intake?

Thank You

Porschetech3 Feb 24, 2016 02:25 PM

https://cimg0.ibsrv.net/gimg/www.6sp...0e6787729f.jpg


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


https://cimg2.ibsrv.net/gimg/www.6sp...1f7e8765ec.jpg


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

cWade Feb 24, 2016 02:27 PM

Very nice!

Thank You

Porschetech3 Feb 24, 2016 02:39 PM

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.

ianarm77 Feb 28, 2016 05:51 PM

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

911C4S Feb 28, 2016 08:29 PM


Originally Posted by ianarm77 (Post 4479249)
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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