My goal here was to achieve a pleasing exhaust note that I could enjoy from the driver's seat in my 3.6 997.2 without spending multiple thousands of dollars.
First, installed the Fabspeed center muffler delete, exhaust note was barely enhanced.
Second, performed the Hanksville hack, exhaust note again barely enhanced.
Third, cut open the stock mufflers and modified as PSE, exhaust note better, but still not good enough.
I noticed that in the shop I work at, the cars that had the best sounding exhaust had high flow cats. So I started pricing high flow cats for the 997.2, shocking.
Considered fabbing my own headers and cats until I found this set for $900 from a company I never heard of, Topspeed Pro 1. I thought I give them a shot, if they suck send them back.
Three days after ordering they are on my doorstep, open them up and surprisingly I am impressed, fully polished, nice TIG welds, sturdy fully welded flanges. Of course this is meaningless if they don't fit.
Well, they bolted up perfectly, no grinding, or modifying needed. O2 sensors wires had to be relocated simply by moving the clips further rearward.
Fire the car up and now I am immediately pleased, finally have achieved the true Porsche exhaust note that I remember from my early 911.
However, next day, CEL came on, cat efficiency code. Installed O2 spacer and that went away.
Was not expecting much in the way of performance gains, but was pleased that I gained 9 peak HP.





Factory cat


200 cell cat






Run 1, Solid line, is stock with Fabspeed center muffler delete, not bad for an engine rated for 345hp at the flywheel.
Run 2, Dashed line, is after header install

 

get the small mufflers from agency power, or same at maxspeed

 

I suggest a tune as well.

 

absolutely get some free flow air filter like bmc or k&n and a ecu tune like evomsit or revo Youll add alot more hp than 10

 

The headers looks great...They look very similar to the green motorsport sport headers. 338 is a nice number from a 3.6, how's the feel compared to stock?

http://www.greenmotorsportusa.com/#!...-sport-headers

 

Get the GT3 tb and IDP race plenum. It really opens the top and and breathes better!

 

I thought the gt3 and carrera 997.2 throttle body were the same size (82mm). Can someone confirm otherwise?

 

My main goal for the the high flow cats was enhanced exhaust note on a budget. Any improvement in performance was secondary. These headers and cats cost nearly half as much as the the mufflers mentioned above.

 

Congrats looks Nice i was looking at these also a few weeks ago.

Can you get a sound clip on these?

Thanks

 

I'm glad I read this thread - I hadn't heard of Top Speed or Max Speed before. I like the idea of the Max Speed cat delete pipes - but now my question is what is the difference between the 'straight' cat delete pipes and the cross over style? There's a $100 price difference.

 

I would love to know what you did to the stock mufflers when you cut them open?
Did you add the tube behind the closed off port?
Pictures?


Thanks!!

 

I'll work on that sound clip
My mods only apply to the 997.2. The 997.1 has a different exhaust layout.


Open the PSE port and cut an opening in the muffler outlet pipe.



Tie the two openings together.



Factory PSE mufflers have a large hole in this inner pipe, much larger than this small drain hole in this non PSE muffler.



Mufflers are made of high grade stainless steel, difficult to cut with hand tools.



In the end, this was a lot of work. A gundo hack would have been much easier and accomplish the same thing.

 

Props for some good welding there. Stainless is not easy to work with.

 

What O2 sensor spacers did you use?

 

http://www.42draftdesigns.com/o2-sensor-spacer/

I used this one based on the angled design, the rear O2 sensors are in a fairly tight location on the 997.2.