Excellent point. DId not think about that.
Stock would have 400cel ( or is it 600 ? ) cats.
X and cross over would either no cats or a much higher flow sport cats.

 

What about sound difference between merged and stock ?

 

=====================================================
Joe Fabiani president of Fabspeed Motorsport USA. Ive owned multiple Porsche air-cooled cars and water-cooled cars and been a PCA member for 37 years. Used to do DE with Bill Verberg and all the 993 , 964, 3.2L and guys at Watkins Glen and other East Coast roadcourses for 20 years.

I run the research and development department at Fabspeed. I CUT OPEN and dissect all Porsche air and wasser cooled exhausts to learn what, why and what constrictions Porsche had to deal with when designing and selling cars.

HERE is what I have learned from Dyno testing, road and race track testing and Sound Quality testing on 993 cars and other Porsche water-cooled cars. The Fabspeed Motorsport team has applied CASD design, Dyno testing and refined our designs over 25+ years. Currently I still own my 1995 993 RS CS tribute car I bought new in 1994 with a 3.8 liter engine and gearbox by ANDIAL Porsche.

1. The straight 993 crossover Cat-bypass pipes , like a person crossing his arms, has these problems and deficiencies. The 2 straight pipes 100% give the driver and listener 2 separate LEFT and RIGHT 3 cylinder sound tracks from the Flat Six engine. YOU are hearing 2 three cylinders at all times. Other problems are 2 separate straight pipes make this old school system EXTRA EXTRA loud and drones versus a quality X pipe system. Why were these straight pipes designed and offered in the 1st place one might ask? Ill tell you its super simple to make straight pipes as it takes no thought no engineering and simple fixtures. Easy to manufacture.

Fabspeed 993 X pipe system. Consists of a CAD designed and flow simulated investment cast X pipe section. This one piece cast X has a center window/ cross over and allows the LEFT &B RIGHT banks of the flat six engine to work together and make more power , better NOT too loud sports car sound and are modular i design. The Fabspeed 993 X pipe also allows HJS German 200 cell cats and race pipes for DE Club racing that slide on and slide off. I should have gotten a US Patent. Truly NO BS you get the very best system that does not droop under the rear 993 bumper cover.

One other thing to mention Flat 6 quality high point he’d sports car sound and NO DROAN no subsonic resonance whatsoever. I used to own a 993 cabriolet and it had Fabspeed Maxflo mufflers and my X pipe with NO CATS. Cabriole top down and or up can totally daily drive the cab and up high through the REVs it has a higher flat 6 pitch that any and all flat 6 engine only emit with a balanced X pipe design.

If yiu have any questions ask for joe@fabspeed.com and or john@fabspeed.com
Feel free to come to Fabspeed and you can drive and sample my 993 RS CS.

 

for the guys running separate pipes, did you end up keeping the stock heat shielding , used nothing, or made your own?

 

Here is a dyno graph of Joe's 993 with our high-flow HJS catted X-pipe vs. Stock, I'll see if I can track down a graph of our bypass X-pipe vs. stock and post that as well!

 

Yup, this is what I was thinking too.

Others have said the cross overs give a deeper throatier sound, so I am guessing it will still be the tone of 2 x 1800cc, 3 cylinder engines