OK. The goal for my 997.2 is to get back a sound closer to a PSE, and any HP/TQ gains are a plus but I do not want -any- HP/TQ loss. I have seen some of these X-Pipe (or even X-Overs) mentioned.......Thinking the X-Pipe by description will get me a nicer sound. OK..................

With all of that being said, I am looking thru the various postings and see some quite varied dyno charts out there. (which concern me). Considering we are talking the same basic configuration of a "U-turn that meets in the middle........ can someone verify or explain how you can either A) Show a loss at varioius RPM ranges ....or B) Show some sizable, or any gains across the range. Again my reason for this posting is, that I see some dyno charts that are extremely different.

I've not listed the vendors as I do not want to get into a pi$$ing match here, but before I make a purchase I'd like to know the facts if possible.


Tx,
BobR

 

you got 997.2 so what 'x-pipe' exists for it is a bit of question. I think only proven x-pipe that was done more or less properly with no air flow issues was fabspeed 997.1 x-pipe 200 cell cats one. so do your research a bit to find those details.

 

AWE has x-pipe and cross-over pipes for 997.2

They claim x-pipe loses a few hp while cross-over gains a few.

AWE posts video clips of both systems on their site. To me the cross-over sounds better?

 

it`s because (IMHO) in their x-pipe design they did 2 intersecting air streams colliding into each other instead of running them strictly in parallel with small connector pipe between those 2 bigger pipes where streams should flow.

but it is just my humble opinion.

 

I was swaying towards the Fabspeed, who knows there could be something slightly different at the intersection, and their demo videos are talking high/low pressure...etc. Somewhere along the line there should be something seen loosing the muffler restriction in that area.

Long-story-short. I'll just get the car dyno'd next week, get the pipe, re-dyno and see what the real-deal is and report back on HP/TQ and Sound. (Think I have a sound meter I can grab for that also).

As-long-as I get a better sound with no power loss I'll be a happy camper. (On the otherhand....)


BobR

 

The closest sounding after market exhaust to PSE is Tubi. Everything else sounds deeper while PSE and Tubi has more rasp to the sound.

Just changing out the center muffler for either a cross over or X pipe will NOT give you the sound you are looking for. If you keep the stock side mufflers the car will still sound stock. The rear center muffler is more of a resonator than a muffler and it does not really muffler the sound all that much.

 

What you are describing is an "H" pipe. An H-pipe is typically used to smooth out exhaust sound and does not promote improved cylinder scavenging (power) on an odd firing engine as much as an X-pipe is supposed to. We use H-pipe on a lot of our Audi systems to improve sound.

The concept of an X-pipe (intersecting streams) is to allow "stacked pulses" coming down one side of the exhaust bank of tubing to escape to the other bank of tubing on an odd firing engine like found in a lot of domestic car V8s (and some Europeans).

The exhaust stream is made up of a series of pulses from the opening and closing of exhaust valves on each cylinder. The X section is designed not to actually let the pulses collide, but to allow them to escape from one side to the other when there is no pulse present on one side (like on an odd firing V8).

The escaping pulse can also cause a low pressure area behind it which "encourages" the pulse coming down that side to accelerate and improve exhaust flow, but that effect is greatly reduced when you account for the cats, tubing bends, and mufflers upstream and downstream of this X. What can be demonstrated on a workbench is not necessarily what is happening on the car with all other parts attached.

We've never had success with X-pipes on even firing engines like the Porsche flat six, and given the general industry theory behind the X-pipe design, that is not entirely surprising.

 

Thanks for the information Utkinpol. You are correct about the different design of the X-Pipe.

Our X Pipe is not designed like everyone elses, our pipes have a much bigger raduis U bend at the X with a small talk area in between. This increases the High pressure at the inside of the bend and low pressure on the outside so it creates the perfect scavenging affect to pull exhaust gases out of the engine faster. That is why our X Pipe makes more HP and TQ and creates a better unique sound. Let me know if you have any questions.
Thanks,

 

Alex....PM sent...... Look forward to ordering mine from you guys next week!

 

I also have a 997.2 and was looking for an aftermarket exhaust with a PSE like sound and lighter weight and hopefully a HP/TQ gain. I got the Fabspeed X-Pipe. Although I am somewhat disappointed with the sound (it is hardly any louder than stock IMO), I do believe that I can feel a slight HP/TQ gain. I did not do any before/after dyno runs so I really look forward to your dyno results after you install your X-Pipe. I think you will be happy with this set-up.

 

Here is a link from public YouTube that was sent to me (with thanks), and it seems to sound closer to what my 04'C4S w/PSE had. Does yours sound similar?

 

KaamaCat,
I am not sure if your last post was directed to me or someone else, but there was no link included in your post. You might want to try it again.

 

Sorry bout't that. (I obviously failed Cut & Paste for dummies). Here it is. I am going to try and schedule some time with a local dyno next week for the "before" pic on the car, then will do "after".............after.

http://www.youtube.com/watch?v=9n6yTHgSa14

 

Bob before you re dyno the car with the xpipe on, you want to put at least 50-100 miles on the car to make sure full adaption takes place. A lot of times you do a mod that can temporarily lean the car out a tad and it will make more hp. After full adaption though you give some of the gains back...If you go to the same dyno they can correct for any differences in atmospheric conditions. Look forward to your results..

Dave

 

that`s correct - disconnect battery for 10 or so minutes then drive about 30 miles at least kicking accelerator quite hard.

But I suspect on 997.2 that x-pipe you speak about does not replace cats, so air flow in exhaust will not be changed by much. On 997.1 cars it has major effect as you remove stock cats and replace them with 200 cell ones which are in fabspeed x-pipe. On 997.2 cars that pipe comes after stock cats if I am not mistaken, so, it may improve things a bit but still is mostly a cosmetic change. Also don`t forget to change stock filter to BMC panel one - it may do more positive effect than muffler change alone.