I suspect you are looking at the post further up the page that seven_227 made which compares our x-pipe to the FVD unit.

The Fabspeed unit is practically identical to our design, and as we showed in our video, apparently has the same internal aerodynamic effects. The outer radii of their U-bends definitely overlap like ours do, and their X is made by sectioning four individual 90 degree bends. The tight 180 bend that makes up either side of the X is too tight to do as a single bend on a mandrel bender. You can see the vertical and horizontal welds on both our unit and Fabspeed's unit to create this X.

The FVD unit pictured above has no overlap and may be what you are referring to as less "abrupt".

 

I'm happy to see that we inspired you to pick up your camera and shoot your own video When you are a leader in the Porsche Exhaust manufacturing industry like Fabspeed is people tend to be inspired by you and follow in your footsteps.
The Fabspeed X-pipe is completely different from the AWE pipe. Maybe you need to read over the post that I made earlier again. Kenny McNeil who heads up our product development has been designing exhaust systems for Porsche street cars and race cars for 30+ years. Between Kenny and myself we have spent countless hours on our dynojet developing new products for the 2009 997.2. I can assure you that our dyno is accurate and we are hooked directly to a weather station that does not allow us to change inputs on our dyno to fool the numbers. Anytime we develop new products on our dyno I always have our factory Porsche PIWIS scan tool monitoring every aspect of the car to ensure we are getting "ACCURATE" data.....There is one key factor that maybe you are missing when building an effective x-pipe which was stated earlier.
Knowing how much of an intersection to create between the two U-Bends is the key to its efficiency. If there is too little area shared the scavenging result will be less. If it is too much of an intersection or the angles of the intersection are to abrupt done the air from one bank runs directly into the opposing bank and slows movement efficiency and lessens horsepower. Also note if too much intersection is used you reduce the total volumetric area of the system. This creates restriction resulting in even more Horsepower loss.
Fabspeed is commited to excellence and will continue to be a leader in the Porsche exhaust market!

 

I guess that is why the video you inspired me to shoot is so relevant here.

Apparently, our overlap and geometry are "done correctly" as the venturi, or scavenging effect, is in force on the bench, just like yours. You did see the tissue trick in our video, right?

The concept of an x-pipe has been around for countless years. If Porsche could unlock upwards 29hp and 29ftlbs torque from such a conventional modification as you guys did, why wouldn't they?

Are you suggesting that they could not get "the math right", either? What is the tradeoff here that they were so willing to leave so much power on the table?

These are honest questions.

 

There are restrictions for car manufacturers, as their cars should pass all of the restrictive certifications worldwide, sound, quality and environment wise.
That's why the after market division dramatically increased in the past generation or so. If Porsche unleashed all of the car's potential, there will be no business for companies like yours, and it will not pass certifications nor would it last for decades.

 

Seven,

Of course you are correct.

But Porsche and most other OEMs do not purposely leave power on the table for the aftermarket to easily unlock. They really could care less about supporting the performance aftermarket. That is what makes our job so hard, especially with a highly engineered car like a Porsche.

That being said, when the performance aftermarket is able to unlock power from these cars, you are correct when you say that it will come with a negative side effect.

For example, high flow catalysts technically would not pass Federal emissions testing for all operating phases (like warm up running). And straight through mufflers are louder, which also may not pass Federal standards, and may also not be appealing to all buyers in their target market-base. Headers can be quite expensive to manufacture vs the stamped process that Porsche uses. These are all trade-offs the performance sub-market is willing to live with in exchange for power and sound improvements.

Yet, even with the negative trade-offs that I describe above, none of those mods on a normally aspirated modern Porsche have historically been able to show a huge single gain by themselves. When used as a system of headers, cats, and mufflers, they have been shown on the last gen 997 to produce approximately what Fabspeed is claiming from a single, conventional, redesign of just one of the components on the 997.2 (center rear muffler).

So I am asking Jeremy of Fabspeed what the negative trade-off is with Fabspeed's piece that can account for unlocking substantial power that Porsche may have purposely left on the table?

With our x-pipe we have not seen any huge manufacturing cost (especially vs how the OE rear center muffler is constructed), sound is not appreciably louder (but it is sweeter), and no emissions devices are touched. There was no groundbreaking application of a radically new technology, either. So, with our design, it kind of makes sense to us why we saw such power results as we did.

As this is a technical discussion thread, I am openly asking honest questions, based on the extensive experience we have had as a tuner and manufacturer in the performance aftermarket. And I hope this discussion stays civil.

 

With all the talk of exhaust, why is no one talking about matching intake systems to really flow the engine??

 

Good discussion guys but I feel we are not really getting anywhere.

1-Why did Porsche use a 3 center muffler (that does not seems to muffle all that much) on the 09 Carrera? Why did the not stay with the 2 muffler design?

2-The cats on the 09 at the end of the headers seem a lot bigger than the 05-08 cats. Do they flow more maybe?

3-With in the rules....why type of exhaust system are the Porsche Carrera race cars in Koni, Grand AM GT, ALMS GT2, Porsche Super Cup and so forth using? Are they allowed to use a X pipe style exhaust configuration?

4-I know the Koni BGB Porsche Carrera is using a X pipe. Why would a winning team use a product that loses HP?

What I find very frustrating is unlike many other car brands there is zero exhaust shoot out articles from independant magazines. Not that I believe everything a magazine tests, I know that with other brands there is always exhaust shoot outs and comparions and tests. If I had a 6speed 09 C2s (mine is PDK) I'd dyno test this stuff myself since I have no dog in this fight. Anyone up to doing this?

 

I like a suggestion that MDrums made earlier in this posting... Is there enough space to design to design a LARGE center muffler (actually two separate mufflers) where the exhaust gasses from left side of the engine pass to the right side and exit right directly, and conversely gasses from the right side of the engine exit left. This would get rid of the three existing mufflers and most of the present exhaust system weight.

The questions that would need to be addressed are:

1) Enough space to implement?

2) Muffler large enough to not get arrested and suffer from resonance problem?

3) Enough back pressure for engine to not lose too much torque?

Appreciate Fabspeed, Sharkwerks, and AWE's responses...

 

No responses?

 

Grease you could theoretically do this and we did try something like this (although it would most likely have intersects) we felt it was too loud in terms of resonance. You could do something to some of the designs found on the TT's. So 1) yes there's space 2) likely too loud and resonance prone and 3) There would be a significant change in back pressure (not what you want for an NA car) and possibly loss of torque.

Also to answer some of the other questions in other posts in regards to dyno and tuning... We have been running/testing the EVOMSit software on the car for a few weeks now but today was the day we wanted to actually validate what we had been feeling/testing/ on the street. So armed with a pair of SDI3 (Siemens) ECUs, a PIWIS, AWD Mustang dyno, our EVOMSit Software/Hardware toolkit (came with the Tuner) we eked out a bit more power. Remember just having a PIWIS isn't enough- you cannot data log with it (unless you want to stand there with a video camera lol). Make no mistake the process wasn't easy (hence I believe nobody else is yet offering software for these cars). With the EVOMSit software a typical 997S PDK car can expect to gain 13HP and 12TQ on 91 octane. The nice thing was that we were able to create, test, tweak and fine tune multiple files on the car and on-site with these tools and gathered a plethora of data. I'll have a full write-up with some pictures, dynos etc... shortly.

 

Keep up the great work bro. I am anxious to get the software on our car to see what it does on 93 octane and with our full exhaust package This is why I always encourage customers to independently dnyo there own cars. This gives the public unbiased results, and there is no need to have a factory PIWIS tester to be able to dyno a car. I believe you are right about the software for the 997.2 as well....there is nobody else that offers software for these cars besides the EVOMSit.

 

We just completed testing our prototype of this configuration yesterday.

Here are some notes:

Without complex and expensive construction, it is extremely difficult to essentially take the two crossover pipes and encase them in muffler cans while providing sufficient sound absorption. The angles of the pipes do not lend themselves to "squared up" inlet and outlet angles that would be needed at the muffler entry/exit, among other obstacles.

Our prototype mimics the factory center rear muffler with a u-bend at each end of the can, however, the inlet/outlet tubing and the internal u-bend are larger diameter than stock. And whereas the stock center muffler has minimal sound absorption ability, our muffler has a greater ability to absorb sound while also providing a harmonic balancing effect within the single can.

Power results were not much more than our crossover pipes.

There is noticeable drone at ~2500 rpms when giving slight load, like going up an incline.

Weight reduction of 19lbs by eliminating the side mufflers.

Summary:

This is a nice "upgrade" for users looking to drop weight, make a few hp, and keep sound volume to civilized levels inside and outside the car.

Here is a sample video:

http://awe-tuning.com/pages/videos/v...earmuffler.cfm

We tested side muffler deletes using the stock center muffler, and in all honesty, it has a very uncivilized volume and a very unrefined tone pretty much at all operating ranges. OK for track, but not recommended at all in our opinion for street use.

 

This discussion will never end; that's great. Now, for the big three - years ago I was the process engineering supervisor at one of our now infamous automobile manufacturers and we dynoed every unit in certain model configuratiions. We calibrated each day, controlled temperature and humidity, and the results were consistent over time - including of course when we brought test vehicles in for retests. Maybe things were primitive back then but we sure NEVER had the variability so many now allude to. When a unit performed outside of our accaptable spec range it was pulled out and the problem remedied; I truly cannot remember a single incidence of this being a dyno or operator problem rather than a vehicle problem. Finally, + or - 3 to 4 % WHP isn't going to make a tinker's damn in our amateur operation of our cars, so who cares? Remember that in a 2006 test day at Sebring Jorg Bermeister was 7 seconds faster in a stock GT3 than the best of a number of drivers in cup car RS's.

 

Well, even several years ago, things were a lot more primitive in the German car world let alone the Big Three. No offense, but those were some "dumb" fuel injection ECUs you were dealing with back then, and they did not contain sophisticated self-protection routines to adapt at high resolution to operating conditions.

Modern German fuel injection tuning keeps getting more and more complex in the interest of emissions and protection of the vastly expensive engines under the hoods. The rule of thumb tends to be the more expensive the engine, the more sophisticated the software tuning to protect it from damage.

Just a few degrees of coolant temp absolutely throws the modern Porsche onto a different ignition timing map, having dramatic results on wheel power. Same with enrichment mapping. A skilled dyno operator working for an OEM would probably not have an issue with that. A less skilled dyno operator working in the unregulated automotive aftermarket certainly is less apt to understand these issues.

And I don't disagree with your comments about single digit power results and what that means in terms of improved acceleration, but our mission is to post the true results, even if they aren't terribly impressive.

 

Todd, Your center muffler sounds great! Did you do any dyno runs with it yet? What is the pricing?

I am currently running the Fabspeed side muffler by pass pipes and have received great comments on the cars sound outside the car....mostly from our younger generation though...ha ha. Inside the car like you said there is a drone at a certain sound frequency under slight acceleration from 2000-2500rpm...other than that the car sounds great from the inside.

How much less drone does your center muffler have?

thanks!