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Tried to read back but the thread was pretty cluttered.
Too dangerous.. everyone who gets involved ends up with mud on their hands or apparent conflict of Interest when it seems like all are good intentioned. Best summary is good vendor working hard to provide good product, seems like Independent testing of dundon gt4 headers not yielding superior results vs other vendors as had originally been planned, and now further testing will happen to get to the Bottom of apparent discrepancy. Jury still out, great vendors great forum happy face
Too dangerous.. everyone who gets involved ends up with mud on their hands or apparent conflict of Interest when it seems like all are good intentioned. Best summary is good vendor working hard to provide good product, seems like Independent testing of dundon gt4 headers not yielding superior results vs other vendors as had originally been planned, and now further testing will happen to get to the Bottom of apparent discrepancy. Jury still out, great vendors great forum happy face
Too dangerous.. everyone who gets involved ends up with mud on their hands or apparent conflict of Interest when it seems like all are good intentioned. Best summary is good vendor working hard to provide good product, seems like Independent testing of dundon gt4 headers not yielding superior results vs other vendors as had originally been planned, and now further testing will happen to get to the Bottom of apparent discrepancy. Jury still out, great vendors great forum happy face
I suppose I'll ask. I have no dog in this fight other than being a GT4 owner considering headers. I do like dundon use of 321ss.
How many of you GT3 and RS owners have validated the claims made by dundon and their headers?
I suppose I'll ask. I have no dog in this fight other than being a GT4 owner considering headers. I do like dundon use of 321ss.
How many of you GT3 and RS owners have validated the claims made by dundon and their headers?
I did. No funny business involved. I had a dyno done with SW bypass and factory exhaust. I did the same thing in very similar conditions on the same dyno with Dundon set-up.
Great thread so far! Hopefully I can add some worthwhile content.
Fabspeed Motorsport USA has been designing, engineering, dyno developing and manufacturing headers and exhaust for Porsche air-cooled and water cooled cars for 25 years. Our focus has been evenly distributed to the development of BOTH race and street performance products.
To that end, Fabspeed Motorsport was chosen as the sole supplier to the Cayman Intercontinental Trophy Cup (ITC) series, a professional NASA racing series, for many years. The competition was fierce from Germany, Italy and USA to supply headers for the Cayman ITC 987/987.2 3.4 and 3.8 liter race cars. Fabspeed was informed by many independent teams that our headers made more power than the competitors while lasting and fitting better. Doug at ITC Indianapolis chose Fabspeed because of these facts.
991 GT3/GT3RS Race Headers
When the first 991 GT3s landed on North American soil, our engineering team immediately got to work and developed a Race Header to maximize the performance of the track weapon. Our initial short tube modular header design was very successful, but there was a demand for more. Consequently, we were approached to enhance a GT3RS and welcomed the opportunity to refine our long tube header design further. After extensive development, including dyno and track testing of various designs, we have uncovered the optimal design to unlock the maximum performance and exhaust flow from the Porsche 991 GT3/GT3RS.
The finished product, our Porsche 991 GT3/GT3RS Long Tube Competition Race Header System has been engineered specifically for track use and built to optimize engine power all throughout the powerband.
Power
We developed our headers to make power with and without an ECU Tune. While the hardware made significant gains alone, we found its full power potential was realized when combined with our proprietary tune. As tested on a GT3RS, our Long Tube Competition Race Header System with ECU Tune adds 38 whp and 26 ft/lbs of torque at 7650 RPM. Further down the rev range, our Header System gives you major mid range grunt: 24 whp and 28 ft/lbs of torque at 4500 RPM. Without the ECU Tune, you can expect solid gains of 24 whp and 16 ft/lbs at 7650 RPM and 23 whp and 26 ft/lbs at 4500 RPM.
Build Quality
At the forefront of the header development was build quality. Our obsessive drive to create the industry's highest quality exhaust solution for the 991 GT3/GT3RS Race Headers led us to use both Burns Stainless Collectors and premium Helical valves.
One of the key features of our header system is the Burns Stainless slip on collectors. If you are not familiar with Burns Stainless - their merge collectors are Motorsport proven and have been widely used in NASCAR, NHRA, ALMS, FIA-GT, and Grand Am as well. Our decision to utilize Burns Stainless slip on collectors was easy, their superior design and 30 years of proven performance in Motorsport racing provided more than enough reasoning. Their collectors are custom engineered using Burns' proprietary X-design parametric computer program. They combine high flow and high velocity to increase and broaden an engine's torque curve all the way to the horsepower peak and beyond.
Throughout the Long Tube Race Header development process, we also took a look at our Side Muffler Bypass Pipes and how we can improve them. In our quest to provide the highest quality exhaust solution for the 991 GT3/GT3 RS, we have decided to utilize premium Helical valves. We chose Helical Valves for their unprecedented quality - which has been proven and is currently used by many OEM manufacturers such as Porsche, McLaren, Ferrari, Lamborghini, and many more. Specifically, they are exact valves used on the 991 GT3 RS. Our valves are not just OEM quality, they ARE OEM.
As far as the exhaust piping, we used T304 stainless steel CNC mandrel-bent tubing from our in-house Unison mandrel bender. As a couple if you already mentioned, there are some advantages of using T321 over T304, but they are minuscule when explored in depth. From research Burn’s Stainless conducted, we found that the investment in using T321 was not worth the benefits it gave over T304. Check out the table below showing how close the two metals are in their elemental properties. Data in table provided by Burn's Stainless.
As you can see, there are only small differences between the two metals Tensile Strength, thermal expansion and thermal conductivity. Yes, those properties are important in Motorsport, but the differences between 304 and 321 are insignificant. In our eyes this wasn’t a compromise, but a decision to spend our resources on other aspects of the product that would give us the greatest return in performance, reliability and longevity. We would have absolutely used T321 if there was a major difference between the two metals, but from our research the benefits of T321 are greatest on paper.
Our Porsche 991 GT3 / GT3 RS Long Tube Competition Race Header System is the culmination of Fabspeed’s 25 year commitment in engineering and manufacturing the exotic car performance products. For further information and pricing, please visit the product page HERE.
If anyone has any interest or questions, please feel to write below or contact me directly.
I think it is unfair to Dundon to drag the GT4 in to this. I have no skin in this game and I am using LT headers from a Competitor on my GT4(none mentioned on this thread for the GT3 comparison) but lets keep these things separate.
I did. No funny business involved. I had a dyno done with SW bypass and factory exhaust. I did the same thing in very similar conditions on the same dyno with Dundon set-up.
370 base HP seems VERY low. Do we have any other members here that have dyno their GT3? Mind posting it up please.
*Edit*
So according to Fabspeeds base dyno run of the RS it made 430. Wow did not know that RS made 50 more HP then the GT3...LOL
So GT4 with Dundon headers makes more HP then Obsessed stock GT3.
YES, granted different dyno etc but still, come on..
Last edited by Nick Yoskin; 01-20-2017 at 11:10 AM.
Don't forget to order the exhaust tips. They add 5WHP or so... And of course 991R rear diffuser to take full advantage of such gains.
What I saw so far was one youtube clip where blue GT3 with DMS pulled exactly same as the stock GT3.
Macca was supposed to give real track time differences. Never saw one.
Another video was a black GT3 racing vs Turbo S. I got same results on a racetrack with my stock GT3.
Ask a tech in Porsche or any reputable tune shop if you have a chance about such gains just from the exhaust itself. They are all gonna laugh unless involved in sales.
So there is only one thing that still keeps me off from getting headers, I have heard that the CEL will be part of your dashboard after you install headers and honestly even if it doesnt mean anything i still dont want to have that on.
01-09-2017, 07:50 PM
