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So tempting. Anyone have any experience with potential for CEL? Also, anyone have pictures of the tail pipes? Do they really stick out far from the rear end of the GT4?
So tempting. Anyone have any experience with potential for CEL? Also, anyone have pictures of the tail pipes? Do they really stick out far from the rear end of the GT4?
The HJS HD 200 cell catalysts were chosen primarily for their exceptional ability to catalyze while allowing greater air flow. The GT4 is less sensitive than most Porsches to check engine lights - you should have nothing to worry about there. Feel free to contact me directly and we can discuss all options and what would be best for you and how we can meet your needs!
__________________ SOUL PERFORMANCE PRODUCTS Quality Exhaust Solutions, Fair Pricing, and Outstanding Service
John Gaydos- Owner, Performance Specialist
Cell - (484) 883-6197 johng@soulpp.com
Been awesome! Def sounds great. Had it back to check bolt tightness with my installer a month ago and all was good. If anything I almost want "more" volume now as I have gotten a bit used to it...but in reality for normal driving it is perfect. I took it to work Fri and Mon this past week and was nice to be able to upshift and get quiet as I had a cop follow me for a bit. At the same time did back road drives Sat and Sun and was a blast. Windows up you just get more of the great engine and exhaust tone. And windows down it's still really loud. My coworkers tell me when I leave the sound reverberating off the surrounding buildings is quite loud. All that just from headers keeping stock tone. I'm running Cobb Stage 2 OTS maps. So no CEL for me. I've had people offline ask me about the headers and I tell them they are great. I don't know if one would get a CEL without a tune or not which is one of the typical Q's I get...
The next addition might be the X pipe for another change to sound...tho honestly DSC or Salter Aero uprights are probably my next "big" mod.... A part of me wants race headers... will see... maybe someone want my catted ones used but I think friends and wife are good with the 80% volume increase already hahaha.
Have the soul exhaust with another manufacturers sport headers and it is perfect for me. Still can hear the radio and carry on a conversation but the tone of the exhaust is much better. Makes the engine sound more special.
Been awesome! Def sounds great. Had it back to check bolt tightness with my installer a month ago and all was good. If anything I almost want "more" volume now as I have gotten a bit used to it...but in reality for normal driving it is perfect. I took it to work Fri and Mon this past week and was nice to be able to upshift and get quiet as I had a cop follow me for a bit. At the same time did back road drives Sat and Sun and was a blast. Windows up you just get more of the great engine and exhaust tone. And windows down it's still really loud. My coworkers tell me when I leave the sound reverberating off the surrounding buildings is quite loud. All that just from headers keeping stock tone. I'm running Cobb Stage 2 OTS maps. So no CEL for me. I've had people offline ask me about the headers and I tell them they are great. I don't know if one would get a CEL without a tune or not which is one of the typical Q's I get...
The next addition might be the X pipe for another change to sound...tho honestly DSC or Salter Aero uprights are probably my next "big" mod.... A part of me wants race headers... will see... maybe someone want my catted ones used but I think friends and wife are good with the 80% volume increase already hahaha.
comet
Hey comet, thanks for all the excellent feedback! Sounds like not only yourself but your colleagues are enjoying the sound lol. For your reference you shouldn't have any CEL without the tune on our street headers. What are your goals for the car moving forward on the performance side? I'd be happy to give you some feedback on the aero and suspension upgrades if you'd like.
In regards to sound, the X-Pipe is a subtle change in sound but you should be able to notice it, it is mostly a smoother exhaust note than much of a change in sound level. If you want a real notable change in the overall sound level again, our competition headers are the way to go. Switching from street to competition won't have much effect on the valves closed sound so you'll still be able to fly under the radar.
Originally Posted by JPR
Have the soul exhaust with another manufacturers sport headers and it is perfect for me. Still can hear the radio and carry on a conversation but the tone of the exhaust is much better. Makes the engine sound more special.
Jpr
Thanks for chiming in JPR! If you ever get some video clips together I'd love to feature your car on our social media. Same goes for you Comet now that I mention it haha
Thanks for a good write-up. One question - are you sure that the factory cats are 800 cell? I found this from the "After-sales training guide" for all 9x1s...I cannot imagine the GT4 would be twice as restricted?
Text only:
Emission Control, Catalytic Converter, Oxygen
Sensors – 9x1 Sports Cars
There is one three-way main catalytic converter with
ceramic monolith (1) per cylinder bank installed at the end
of the flow-optimized exhaust manifold. The catalytic
converter diameter is 125 mm, the length 120 mm, it has
400 cells and a wall thickness of 4.5 mm. The oxygen
sensor LSF downstream of the catalytic converter (3) is
installed seven tenths of the way along the length of the
main catalytic converter; this corresponds to 84 mm from
the intake surface. The funnel (4) upstream and downstream
of the catalytic converter is air-gap insulated to
reduce the emission levels.
Bank-
I've never done something like this so ask from ignorance. How does a sport catalyst like this fit under CARB standards? I assume it just doesn't and one can get away with it until the day in the future when an emissions check is required. At that point, I'm guessing you would swap back to stock headers and cats for as long as needed.
@CardiffDweller Correct it doesn't fit. Technically if you get stopped and they think you have mods etc they can send you to the referee / BAR program and you have to pass...which basically means swap off, inspect, then put back on. Same as you would have to do when it is time to pass SMOG as well. There's new law in CA for 2019 as well that is now no longer a fix-a-ticket and is more a for sure being sent to the REF station. This is another reason I went sport cats vs. race.
As a side note I met another person with cargraphics sport headers.. which I compared in another thread. This time around with aggressive driving was louder than stock. But basically same as far as I could tell as my soul headers. Maybe slightly more gritty but pretty similar. Also has more miles on them so possible it's just letting more through..heh.
I've never done something like this so ask from ignorance. How does a sport catalyst like this fit under CARB standards? I assume it just doesn't and one can get away with it until the day in the future when an emissions check is required. At that point, I'm guessing you would swap back to stock headers and cats for as long as needed.
Here is a good reference for you. Magnaflow makes some CARB compliant catalytic converters but they are considered OEM replacement and perform within parameters set for stock vehicles - aka not a performance modification.
@CardiffDweller Correct it doesn't fit. Technically if you get stopped and they think you have mods etc they can send you to the referee / BAR program and you have to pass...which basically means swap off, inspect, then put back on. Same as you would have to do when it is time to pass SMOG as well. There's new law in CA for 2019 as well that is now no longer a fix-a-ticket and is more a for sure being sent to the REF station. This is another reason I went sport cats vs. race.
As a side note I met another person with cargraphics sport headers.. which I compared in another thread. This time around with aggressive driving was louder than stock. But basically same as far as I could tell as my soul headers. Maybe slightly more gritty but pretty similar. Also has more miles on them so possible it's just letting more through..heh.
Yeah that new law is a PIA. I mean chances are slim that it would come to that, but if it does, it is a lot of labor. Although one might get good at swapping headers over time.
Nice write up and this is an interesting option. I am really more interested in getting more mid range power, to fix the torque dip. I want to keep cats and I don't want to break the budget, so keeping the stock muffler would definitely accomplish that. The question is, are the power gains worth it?
AND what are you doing for Laguna Seca? Have you been there since? I guess you would have to install the track Nanny GPS device like everyone else?
I haven't been back to Laguna Seca yet still...but our cars will break sound even OEM there... so already I was lifting and up shifting a gear and moving over to left side when I passed sound booth before I added header... I imagine same technique would work...that or else a GPS device like you say.
08-03-2018, 05:01 PM
