Mike/A.W.E.

Hello,

One of our local dealerships was kind enough to give us a car for development.

With all new products we first start with extensive dyno testing and data logging in stock form. A solid and consistent baseline is the name of the game. We use our in house Mustang Chassis Dyno.







When we get all of the information we need, the car is then moved to our prototype lift. This is where Ron, our Chief Fabricator, does his job. He along with our engineering staff will then design a working prototype using computers and classic hand fabrication that gets retested on the same dyno. If they like what they see and hear, it will then get moved back on his lift. He will then design a jig so the system can be reproduced.





First, here is a baseline dyno sheet of the 997.2 C2S 6 speed. Based on a claimed 385 crank hp, a 1.12 correction factor is suitable to estimate crank hp from whp.





Next, some prototyping pictures.

The OEM header is a tortuous design intended to package the cat close to the exhaust ports to enhance cold emissions output. Further, the primary tubes are hydro formed to allow access to the flange bolts. This all adds up to a lot of potential power to unlock:





We completely digitized the fender muffler, header/cat, and center muffler cavities on the car which then allowed us to do some header CAD and CFD modeling based on bend radii, tubing length, and tubing diameter. We relied on past 3.8l development to guide us here with some basic component characteristics. Here is a fully CAD modeled header:





We then got to work on mocking up some actual test headers. Even with our prototypes we will back purge our welds to ensure minimal burn through for optimized internal tube flow.





At the same time, we have been jigging for new fender muffler replacements, which has been going quickly:





We intend to test center muffler replacement sections, and began by digitizing the OEM component:






We have played around with H and X pipe configurations on various mid and rear engine vehicles, and we have not found it to be a suitable power solution when tight radii are used to enter and exit the cross over or there is a long distance to bridge between bank runs. We see best success on front engine cars where we can make the transition into the X cross over more gradual, or can bridge the banks in 2" or less on an H-pipe, which then has the intended increased scavenging affect. For example, here is an X pipe prototype we did a while ago for the Gallardo. This designed sounded absolutely incredible, but lost power in the upper portion of the rpms where the tight radii became a bottleneck. We have seen similar negative results on other applications.





We will prototype a cross over on the 997.2 simply because there is some harmonic balancing happening in the OEM center muffler due to the shared can, but even with careful CFD modeling ahead of time, we do not expect any different power results than what we have seen in the past. We'll share our findings.

I'd also like to address some concerns out there about our choice of muffler shape. It has been suggested that it is impossible to build a flat or square shaped muffler that will not crack. While I do admit that it more difficult to create a stable flat sided design, it is not impossible, and not only have we evolved our mufflers to cope with the stresses seen with a flat sided design, we are pleased to provide proof that even Porsche will uses a flat sided muffler when needed.

For example, look at the picture above of the center rear muffler. It is triangular in profile, with flat stamped end caps. Like us, the factory has incorporated stress reducing/stabilizing elements like the use of internal side to side braces/pins, and flanged lateral seam welds on the cans. The OEM 997 GT2 center muffler has mostly the same construction.

Even the OEM fender mufflers have a flat profile on one side, as seen in this picture:



So to set the record straight, there is no inherent inferiority in using a flat sided muffler design as long as the stress propagation properties are accounted for, as they are in the latest designs from us and Porsche.

Any questions regarding our R&D on this new model, please ask! We pride ourselves on doing the far majority of our engineering, fabrication, and manufacturing work in house, and try to be as transparent as possible when it comes to our design philosophy and methods.



HEADERS:

I thought it would be interesting to share how we design and manufacture our jigs on which we ultimately build our products.

Years ago, we used to do our whole prototype process by "hand", meaning that we would cut and weld mockups and modify them for performance and fitment. And then once we had a final design, we would hand build an apparatus by which we could reproduce the part in volume, all the while trying to ensure the construction was as efficient as possible. It was a very laborious and lengthy process.

Since we interfaced our manufacturing with our pre-existing CAD/CAM software 3 years ago, our development process has steadily gotten faster and faster. That, along with the acquisition of more CNC equipment, really has streamlined our R&D and ultimately we are producing better products from our manufacturing line.

As I stated in my previous post, we first digitize the entire muffler and header/cat cavities of the vehicle, as well as the actual components themselves. This allows us to "virtually" work with the vehicle and products on our PC workstations, which in turn allows us to solve performance and production challenges. For example, instead of physically mocking up headers on the car, we can solve tubing runs for equal flow and manufacturing simplicity on the computer. Much faster!

Correspondingly, we can quickly design and manufacture the jigs that the parts will be produced in since we have a full 3D mockup of the exhaust already in virtual space:







Here is the pathway of our jig building:

First, we CAD (Computer Aided Design) render the jig parts based off our 3D exhaust models. Then in our CAM (Computer Aided Manufacturing) program, we instruct our CNC (Computer Numerically Controlled) equipment to actually make these parts . CAD -> CAM -> CNC.

Here is a jig part program in our CAM suite:





Here is the same part being cut by our CNC horizontal band saw based of that program:



Here is that part that was cut by the CNC saw being flycut for true flatness and being drilled and tapped for fixture interface in our CNC mill:



And here are similar jig parts assembled into a functional jig:



And then finally a prototype part that is fitted to the car:





Ultimately, we will dyno and street test these parts to ensure performance and sound quality, and if the need to redesign any component ocurrs, we can easliy do so since the whole R&D process is now modular. We can zero in on the component that needs a tweak instead of tearing the whole system apart.




X PIPE:

We tested an x-pipe design for this car. It made a very nice sound and we plan on offering it for people looking to change the tone of the vehicle and save a little weight without sacrificing a lot of power:





A better option for weight loss is our rear muffler delete cross over pipes. Not quite as sweet sounding as the x-pipe, but we recorded gains throughout the rev range:





Our mufflers, headers, and cats are completed and are in their final round of power testing. Here is a picture of the header set:





And here is a close up photo showing our usual attention to detail where we hand grind the internal welds to maximize exhaust flow:






A couple photos of the complete system on the car:







And here is shot showing ground clearance. Even with our long tube headers, we managed to model our tube run not to hang any lower than stock. We increased available space to lengthen the header primaries by moving the cats to where the rear center muffler used to go:



Here are the dyno sheets of our x-pipe and cross over rear muffler deletes.

First is our cross over system. It is a direct plug in replacement for the factory center rear muffler, using 2.5" diameter tubing. Max gains were ~5 crank hp and ~5 crank tq, with improvements throughout the rpm range. We feel these are very realistic and expected gains, as the OE rear muffler is not immensely restrictive as the side mufflers are doing the bulk of the sound control. Gains are seen from providing a straight through path vs forcing the exhaust gas through a baffle system in the OE unit. Gains are also seen from enlarging tube diameter slightly vs stock. We anticipate an MSRP of $695 for this product. T304 stainless steel construction.





Here are the results of our x-pipe system. As we anticipated, the extra tube length run and bends did not help power. But also as we anticipated and have seen on other cars during development, the tone produced by this configuration is very, very sweet. For people looking only for sound improvement and a slight weight loss, this is a nice, albeit power robbing, mod. We are shooting for an $849 MSRP on this product. T304 stainless steel construction.





Finally, here is an overlay of stock, our x-pipe, and our cross over systems:





We are aware that our results here may fly in the face of results posted by other sources, but rest assured that as always we did our due diligence when dyno testing these products in house.

Same day, back to back testing was done to minimize weather and mileage variables, and full multiple scan tool monitoring was done, including the use of our PIWIS factory tool, to ensure controlled vehicle state test conditions.

Without these controls in place, we have seen that it is extremely easy to produce invalid data.



Weights:

OE center rear muffler with straps: 16 lbs

A.W.E. Crossover Pipes: 9.5 lbs (7.5 lbs savings)

A.W.E. X-Pipe: 10.5 lbs (5.5 lbs savings)



Video:

Here is the "cross over" delete video:

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

And here is he "X-pipe" delete video:

http://awe-tuning.com/pages/videos/v...97.2_xpipe.cfm

Notice how the cross over pipes sound a touch raspier than the X-pipe. Especially notice the off throttle and part throttle "burbling" that the cross over pipes have that the X-pipe does not. If the X-pipe had the power results of the cross over pipes, that is the only version we would sell!



Here are pictures of our side mufflers:





More video:

Here is a video of our side muffler with cross over pipes, utilizing the stock headers/cats.

Notice how the puttering noise is dramatically reduced. I find this to be my favorite sound combination so far. Interior drone is zero! And in our tradition of designing true street friendly, daily driver exhaust systems, the outside volume is not overbearing.

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


We've also released our 997 and 997S bolt-on tips today (our manufacturing department has been cranking overtime!).

Pictures:







As always, please visit our web site for more detail.

http://awe-tuning.com/pages/shared/p...fm&PPT=Exhaust

GreggT

Pretty neat Mike....you guys have been busy.
Thanks for sharing.

Jon70

Great post and very impressive work. The 997.2 looks especially good in black.

Dave in Oregon

Very interesting and informative. Thanks so much for taking the time to post such a comprehensive overview.

jlinmd

Mike the X-Pipe really sounds sweet! It's throatier, raspier, and smoother than the Fabspeed X-pipe, which has a little bit of burbling with throttle tips. Did your butt dyno notice the power loss during the test drives?

MHC2S

Very impressive shop you guys have over in PA. I'll have to stop by some time to check it out. Thanks for the pic's and info. It's amazing just how differnent the 997 and 997.2 exhaust systems are.

Chris from Cali

Mike - Thanks for posting that. Very impressive R&D.

I think it's a big boost to a shop's credibility when they post the "how"... Personally, I'd feel very confident buying your products given the openness and honesty. To admit that one of your products loses power (albeit with a sweet exhaust note) takes guts.

Congrats on some very nice parts...

Mike/A.W.E.

I will be perfectly honest. I did not.

I am in and out of cars all of the time. I am no pro, but my sensitivity level I feel is better then average.

I am also very critical of our products. I am the first to complain if I don't like something. Myself and the President of A.W.E. conduct most of the test driving. After years of working with eachother, we have similar tastes. We know what will sell and what will not.

The fact that it robbed some power bugs me, but I too like the sound.

Mike/A.W.E.

You just summed it up right there. That is exactly why we do things the way we do.

You are not too far from us. If you are ever in the Philly area, please pop in. I will give you the nickel tour.

Mike/A.W.E.

GT, it's a shame you are so far away. I think you would be impressed with our facility.

How is your car? Get the suspension dialed in?

mdrums

The X pipe is smoother sounding...the cross over pipe (2 seperate pipes) are raspier sounding. I think you have it backwards.

GreggT

All's fine so far Mike.....the boys at Kelly Moss enjoyed working on the new one, and it all came together pretty well.
Thanks again for your assist.
Be assured that if I can get your way, that a stop at AWE would be planned.

Mike/A.W.E.

^^^ agree^^^.

X-pipe smooth, but loses power.
Crossover is raspier and more raw, but we see gains.

gota911

Mike, jlinmd was making a comparison between the A.W.E. X-pipe and the Fabspeed X-pipe, not the A.W.E X-pipe versus A.W.E. cross over pipes.

jlinmd

At least that's what my impression was when I listened to the sound from both AWE and Fabspeed X-pipe videos back to back. The Fabspeed X-pipe sounded a little rougher and the AWE X-pipe sounded smoother. It's all personal taste.