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Well, thanks for your patience, and I'm pleased to say results are in. The revving issue that I had to take the first set of Fabspeed headers off for turned out (at least according to my dealership) to be something other GTSes do too. It's a very slight lift of revs, sometimes, after the car comes to a halt. They showed me a demonstrator GTS that did the same thing, which was good enough for me. It doesn't annoy me if I know it doesn't mean there's anything wrong with the car. It might have been better had they found that out before I spent hundreds of pounds changing bits of exhaust round and round, but that meant I got to do some science...
So to briefly recap, I had Fabspeed sport headers on the car, which I then dynoed alongside the stock headers and found there to be no change. In fact, the best run with the stock setup was slightly better than the FS one, as below:
When I shared this information with Fabspeed they were extremely courteous and helpful, and exchanged the headers, at a discount, for a set of 'GTS-specific' ones, with a wider-aperture cat. These headers were also less highly polished than the original headers at my request, and I had them fitted a couple of weeks ago.
In terms of sound I was initially a little disappointed. The smaller-cat FS headers produced an incredible resonance that really made the car howl, and the new ones, while increasing volume slightly from stock, didn't have quite the same character. The sound was almost less dramatic, with what had been extravagant banging on overrun converted into something more like a menacing rumble. I think they're banging a bit more having bedded in now, or I've just got used to it, or I've forgiven them, for reasons that will become clear below!
Because I did feel a definite bump in performance. The car seemed to have gained about 400cc - around town it felt like a muscle car, seemingly very powerful at 3,000rpm and with the needle flying to redline more quickly than before.
Or so I thought, but then again I also though the previous headers added power, but the dyno told me otherwise, so it was time to test the new ones. And the news is good. Here is the dyno printout comparing the best stock run from the graph above with the best run with the new 'GTS' Fabspeed headers:
This is not a same-day comparison, but the difference is large. The headers led to a 14hp and 18ft/lb bump at peak, with the TQ peak coming in 350 rpm earlier, but the really remarkable thing is the difference in midrange - at 4,000rpm the difference is almost 50 ft/lb. This explains the car's turning into a city-street weapon!
Here is the graph of wheel HP
And here the one with drivetrain loss adjusted so that stock crank HP equals Porsche's stated figure of 430.
Pretty striking, and more than I dared hope would happen. I want to say a big thanks to all at Fabspeed. Not only have they made a great product that has just been independently proven to do what they said it would (and it is independent - if these headers hadn't made the car more powerful then I would have sent them back just like I did the last ones), but the way they handled the whole matter was outstanding. A lesser company might have questioned my dyno methods, or come up with an 'individual results may vary' excuse, but they took my findings simply as data, which challenged them to build something better, and then build something better they did.
It feels like all of us who like to make our cars a little extra-special can take heart from the fact that there are businesses out there who value fast cars more than fast bucks.
And don't those less polished headers look nice! Feels cool to have a product that was specially made for me, but hopefully all you GTS owners will read this review and they won't be unique for long...
Is yours a PDK? I wish the final test could have been run -- i.e. line it up against another stock PDK GTS before your mods and afterwards. Run them 4 or 5 times with launch control and a starting flagger. See if the dyno translates into a real world speed delta.
Better yet, don't actually do the mods but put some Fabspeed stickers in the window and see if that gets the same results!
Awesome that you're seeing measurable results for your bucks. Congrats -- your car is a gem. And all in the name of science, too!
Josh you have been nothing less than a gentleman during this entire process, and we very much appreciate the opportunity to work with you and the GTS community to turn this situation into a win-win. We are always striving for perfection, and given the opportunity to improve we will jump at the chance. We are thrilled to see the expected results tested and confirmed on your end, and very much appreciate the kind words and update to your wonderfully scientific thread
BEAUTIFUL new addition to the garage btw
Originally Posted by NoGaBiker
Is yours a PDK? I wish the final test could have been run -- i.e. line it up against another stock PDK GTS before your mods and afterwards. Run them 4 or 5 times with launch control and a starting flagger. See if the dyno translates into a real world speed delta.
Better yet, don't actually do the mods but put some Fabspeed stickers in the window and see if that gets the same results!
Awesome that you're seeing measurable results for your bucks. Congrats -- your car is a gem. And all in the name of science, too!
Hey hey, our stickers are worth at least 10hp...depending on what they came with lol
1. Do you also have your center mufflers (where the PSE valves are located) changed over to an X-Pipe with PSE valves? From your photos of the end of your header (at the end of the cat, where it bolts to the pipes for the center mufflers) it looks like you still have the Porsche OEM system installed.
2. I have just installed ("I did it myself," totally thanks to the inimitable Larry Cable and his step-by-step instructions for the install of the AWE X-Pipe, which took me all the way, except for the last steps- my X-Pipe is the Fabspeed version) the Fabspeed PSE X-Pipe center mufflers by-pass. I have been thinking about adding the FS GTS headers and 200 cell cats, which your scientific experiment did so much to inform all of us. Other than the cost of adding the headers, I was concerned that the car would end up being just too loud for me, as well as kick it over the decibel level at some tracks.
3. Per Larry's suggestion, since the entire rear of the car was exposed, I replaced the OEM air filters with BMC. The last few days here in New England have been hot, particularly today, so after spending so much time getting the rear elevated and getting the rear exposed, then having the X-Pipe installation take quite a bit of time, effort, and adjustment, when I finally tightened the last T25 screw this morning I came back inside and took a nap. So, I have not driven the car yet, just test-fired it up to check that everything was tight and working correctly. I did mention to FS in an email yesterday that an Installation PDF would have been a godsend.
4. I have now recovered (by the way, just to be clear, this whole process consumed parts of three days), so I plan to drive the car vigorously tonight, and perhaps Sunday morning as well. I have some doubts that I will feel any improvement, but FS does not claim very much for the X-Pipe. Can't wait to hear if it sounds different/better/worse/the same. Will post afterward, by Sunday morning.
5. I also purchased the Cobb AP, which I have not yet installed. Larry recommended that I wait until after the X-Pipe and BMC filters were installed, which was another piece of great advice. However, since I wanted to be certain which map I should be looking to download from Cobb, I called them Friday afternoon. Alas, their crew must have abandoned ship to get an early start on the US Memorial Day weekend, which goes through this coming Monday. I have not yet decided whether or not to take the chance on a basic installation of the Cobb software for the GTS. I would really like to get that done over the weekend, then talk with Cobb Tuesday morning. If, by chance all of that works, the next planned step was to have Fabspeed send me the software ($250) for their Stage 1 GTS tune. Somehow, getting up to speed with Cobb, and then another tune by FS, all on next Tuesday, before say 3 pm, seems a little optimistic.
6. None of this timing would be important, except that at some hopefully reasonable time on Tuesday I am leaving for two track days at Watkins Glen. That's seven hours driving time, not counting any pit stops, unless I'm willing to risk a big speeding ticket. I have good radar protection, but nothing particularly advanced for laser. Basically, I've decided to keep a lid on my speed, at least for the most part.
7. As to taking the GTS to the track: this is my very first time tracking the car. My previous car was a Cayman R 6MT. The GTS has PDK. I have some, but not really very much, track experience, but none for the past two years. Tires will be the OEM P-Zeros. Suspension is OEM stock PASM, not SPASM. If I have time I will try to post my sense of the car by next Friday. I'm staying to work at the PCA Club Races that take place at the Glen June 3-5, so there may be some delay in my response to all of this.
8. I cannot be compared to THE MagicRat in providing post-experience analysis, but I will do my best to make it clear enough for you guys to understand.
Magic Rat, thanks so much for the write-up and being one of the first GTS owners with Fabspeed Sport headers. Glad FS released the updated sport headers for the 991 GTS. My GTS's upgrade path with be sport headers first for a bump in the mid-range, BMC filters, and COBB tuning. I might consider X-pipes for volume in phase 2.
Did you notice any volume bumped with the sport headers alone?
1. Do you also have your center mufflers (where the PSE valves are located) changed over to an X-Pipe with PSE valves? From your photos of the end of your header (at the end of the cat, where it bolts to the pipes for the center mufflers) it looks like you still have the Porsche OEM system installed.
2. I have just installed ("I did it myself," totally thanks to the inimitable Larry Cable and his step-by-step instructions for the install of the AWE X-Pipe, which took me all the way, except for the last steps- my X-Pipe is the Fabspeed version) the Fabspeed PSE X-Pipe center mufflers by-pass. I have been thinking about adding the FS GTS headers and 200 cell cats, which your scientific experiment did so much to inform all of us. Other than the cost of adding the headers, I was concerned that the car would end up being just too loud for me, as well as kick it over the decibel level at some tracks.
3. Per Larry's suggestion, since the entire rear of the car was exposed, I replaced the OEM air filters with BMC. The last few days here in New England have been hot, particularly today, so after spending so much time getting the rear elevated and getting the rear exposed, then having the X-Pipe installation take quite a bit of time, effort, and adjustment, when I finally tightened the last T25 screw this morning I came back inside and took a nap. So, I have not driven the car yet, just test-fired it up to check that everything was tight and working correctly. I did mention to FS in an email yesterday that an Installation PDF would have been a godsend.
4. I have now recovered (by the way, just to be clear, this whole process consumed parts of three days), so I plan to drive the car vigorously tonight, and perhaps Sunday morning as well. I have some doubts that I will feel any improvement, but FS does not claim very much for the X-Pipe. Can't wait to hear if it sounds different/better/worse/the same. Will post afterward, by Sunday morning.
5. I also purchased the Cobb AP, which I have not yet installed. Larry recommended that I wait until after the X-Pipe and BMC filters were installed, which was another piece of great advice. However, since I wanted to be certain which map I should be looking to download from Cobb, I called them Friday afternoon. Alas, their crew must have abandoned ship to get an early start on the US Memorial Day weekend, which goes through this coming Monday. I have not yet decided whether or not to take the chance on a basic installation of the Cobb software for the GTS. I would really like to get that done over the weekend, then talk with Cobb Tuesday morning. If, by chance all of that works, the next planned step was to have Fabspeed send me the software ($250) for their Stage 1 GTS tune. Somehow, getting up to speed with Cobb, and then another tune by FS, all on next Tuesday, before say 3 pm, seems a little optimistic.
6. None of this timing would be important, except that at some hopefully reasonable time on Tuesday I am leaving for two track days at Watkins Glen. That's seven hours driving time, not counting any pit stops, unless I'm willing to risk a big speeding ticket. I have good radar protection, but nothing particularly advanced for laser. Basically, I've decided to keep a lid on my speed, at least for the most part.
7. As to taking the GTS to the track: this is my very first time tracking the car. My previous car was a Cayman R 6MT. The GTS has PDK. I have some, but not really very much, track experience, but none for the past two years. Tires will be the OEM P-Zeros. Suspension is OEM stock PASM, not SPASM. If I have time I will try to post my sense of the car by next Friday. I'm staying to work at the PCA Club Races that take place at the Glen June 3-5, so there may be some delay in my response to all of this.
8. I cannot be compared to THE MagicRat in providing post-experience analysis, but I will do my best to make it clear enough for you guys to understand.
sorry about that - I figured that the install instructions were good enough that I didn't need to duplicate them
Yes what I have is the FS sport headers alone with PSE, though a Kline cat-back system on its way soon.
Still really happy with the headers, and I do think that over a couple of '000 miles now the sound has improved. Might just be that I've just got used to it, but it seems the slight harshness that was there when I first had them installed has gone, and of course the extra power never gets old!
Looking forward to seeing what the Kline does and will of course post full report, though probably won't dyno as they've said to me it won't add much in the way of power but will make a very lovely sound...
1. Do you also have your center mufflers (where the PSE valves are located) changed over to an X-Pipe with PSE valves? From your photos of the end of your header (at the end of the cat, where it bolts to the pipes for the center mufflers) it looks like you still have the Porsche OEM system installed.
2. I have just installed ("I did it myself," totally thanks to the inimitable Larry Cable and his step-by-step instructions for the install of the AWE X-Pipe, which took me all the way, except for the last steps- my X-Pipe is the Fabspeed version) the Fabspeed PSE X-Pipe center mufflers by-pass. I have been thinking about adding the FS GTS headers and 200 cell cats, which your scientific experiment did so much to inform all of us. Other than the cost of adding the headers, I was concerned that the car would end up being just too loud for me, as well as kick it over the decibel level at some tracks.
3. Per Larry's suggestion, since the entire rear of the car was exposed, I replaced the OEM air filters with BMC. The last few days here in New England have been hot, particularly today, so after spending so much time getting the rear elevated and getting the rear exposed, then having the X-Pipe installation take quite a bit of time, effort, and adjustment, when I finally tightened the last T25 screw this morning I came back inside and took a nap. So, I have not driven the car yet, just test-fired it up to check that everything was tight and working correctly. I did mention to FS in an email yesterday that an Installation PDF would have been a godsend.
4. I have now recovered (by the way, just to be clear, this whole process consumed parts of three days), so I plan to drive the car vigorously tonight, and perhaps Sunday morning as well. I have some doubts that I will feel any improvement, but FS does not claim very much for the X-Pipe. Can't wait to hear if it sounds different/better/worse/the same. Will post afterward, by Sunday morning.
5. I also purchased the Cobb AP, which I have not yet installed. Larry recommended that I wait until after the X-Pipe and BMC filters were installed, which was another piece of great advice. However, since I wanted to be certain which map I should be looking to download from Cobb, I called them Friday afternoon. Alas, their crew must have abandoned ship to get an early start on the US Memorial Day weekend, which goes through this coming Monday. I have not yet decided whether or not to take the chance on a basic installation of the Cobb software for the GTS. I would really like to get that done over the weekend, then talk with Cobb Tuesday morning. If, by chance all of that works, the next planned step was to have Fabspeed send me the software ($250) for their Stage 1 GTS tune. Somehow, getting up to speed with Cobb, and then another tune by FS, all on next Tuesday, before say 3 pm, seems a little optimistic.
6. None of this timing would be important, except that at some hopefully reasonable time on Tuesday I am leaving for two track days at Watkins Glen. That's seven hours driving time, not counting any pit stops, unless I'm willing to risk a big speeding ticket. I have good radar protection, but nothing particularly advanced for laser. Basically, I've decided to keep a lid on my speed, at least for the most part.
7. As to taking the GTS to the track: this is my very first time tracking the car. My previous car was a Cayman R 6MT. The GTS has PDK. I have some, but not really very much, track experience, but none for the past two years. Tires will be the OEM P-Zeros. Suspension is OEM stock PASM, not SPASM. If I have time I will try to post my sense of the car by next Friday. I'm staying to work at the PCA Club Races that take place at the Glen June 3-5, so there may be some delay in my response to all of this.
8. I cannot be compared to THE MagicRat in providing post-experience analysis, but I will do my best to make it clear enough for you guys to understand.
Great insight and dedication to an educated decision! Wish I had seen your post earlier, and just you over a PM to chat about the Headers. How was the Glen? New pavement was great when I was there haha.
Originally Posted by Jnosol
Magic Rat, thanks so much for the write-up and being one of the first GTS owners with Fabspeed Sport headers. Glad FS released the updated sport headers for the 991 GTS. My GTS's upgrade path with be sport headers first for a bump in the mid-range, BMC filters, and COBB tuning. I might consider X-pipes for volume in phase 2.
Did you notice any volume bumped with the sport headers alone?
Jimmy thanks for chiming in and look forward to taking things up a notch on your GTS when you are ready. Should be just as fun as the GT4 if not more so haha.
Originally Posted by MagicRat
Hi All,
Yes what I have is the FS sport headers alone with PSE, though a Kline cat-back system on its way soon.
Still really happy with the headers, and I do think that over a couple of '000 miles now the sound has improved. Might just be that I've just got used to it, but it seems the slight harshness that was there when I first had them installed has gone, and of course the extra power never gets old!
Looking forward to seeing what the Kline does and will of course post full report, though probably won't dyno as they've said to me it won't add much in the way of power but will make a very lovely sound...
Josh always a pleasure to hear your individual feedback and to see you chasing down the perfect driving experience. I wish you the best of luck with the Kline system and hope it meets your goals!
Last edited by John@Fabspeed; 08-09-2016 at 06:59 PM.
I just want to say a big thanks to John from Fabspeed and MagicRat. You've been very kind to share your insights and experiences regarding 991 GTS Exhaust and Sport Headers.
You guys make this community a great place to share knowledge and passion.
05-26-2016, 06:32 PM
