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I appreciate your thoughts and I am very realistic with regards to torque and hp gains. I don't expect more than 10-15 hp in the mid-rpm. However, your arguments are not very convincing eapecially that all data points and track oriented 911s choose high flow cats. You will argue they're targeting high rpm gains, sure, however they won't do this if the loss were significant in low and mid-rpm ranges. So far feedback gathered about GT3, GT4 and some Ferrari cars agree on better throttle responsiveness and higher torque in low/mid rpms with 200 cell cats. Finally as I stated it I will document this mod with dynos before and after so no more speculation is allowed
We all justify these mods the way we want to. I'd bet a lot of money this car performs no differently. This is "a Dyno" but it is not a dyno of the same car, in the same conditions, on the same da,y on the same dyno, etc... with and without modifications..
It's a dyno of the same car on the same dyno in the same place with the same dyno operator, with and without one specific mod. Not the same day I'll admit, but we can't have everything! Here is the whp readout if that's helpful:
In the case of my car the Fabspeed GTS headers certainly increased torque substantially. I accept that individual dyno results may vary, but 30 wheel-lb/ft at 4,000rpm was good enough for me...
Thanks MagicRat. Could you elaborate on how throttle response and torque feel under 3000 rpm? Did you feel it right after installation or did it take sometime for the ECU to adapt?
Thanks MagicRat. Could you elaborate on how throttle response and torque feel under 3000 rpm? Did you feel it right after installation or did it take sometime for the ECU to adapt?
I feel like it took a while to take effect, but this may be due to another factor. My tuning shop is out of town, and every time they've done work on the car I only really feel it when I get back to London and roads I know well. Cruising around my neighbourhood the night after the install, the car felt like it had turned into a 4.0 - only way I can describe it.
The mod that definitely felt like it did something immediately though was the pro tune I've had from Fabspeed via Cobb Accessport. This definitely improves 'throttle response', though I confess to being a little sceptical about the term (one can after all just press the pedal harder to get more response!). The engine feels cleaner revving now though, and the car seemed much faster on a section of country road I know well. Will post a dyno once I get it back into the shop. May just be that normal mode has turned into sport more on the throttle mapping but I don't think so...
Is an ECU reset required right after changing headers and cats? If so how shall I proceed?
I have not done any of this on my GTS yet but I believe nothing is needed to be done too the ecu. The 200 cell cats sometimes triggers a fault because they aren't as efficient as the stock units. Sometimes tuners offer extenders for the o2 sensors to get them out of the stream. Less likelihood of triggering a fault that way.
Is an ECU reset required right after changing headers and cats? If so how shall I proceed?
Not required as your ECU will learn the improved exhaust flow (for catted headers, catless race headers require a tune). However, the first week you may get a bit of hesitation in throttle response. You can reset the ECU by unplugging your battery for 15min. This is based on my research, feel free to correct me if I'm wrong.
I appreciate your thoughts and I am very realistic with regards to torque and hp gains. I don't expect more than 10-15 hp in the mid-rpm. However, your arguments are not very convincing eapecially that all data points and track oriented 911s choose high flow cats. You will argue they're targeting high rpm gains, sure, however they won't do this if the loss were significant in low and mid-rpm ranges. So far feedback gathered about GT3, GT4 and some Ferrari cars agree on better throttle responsiveness and higher torque in low/mid rpms with 200 cell cats. Finally as I stated it I will document this mod with dynos before and after so no more speculation is allowed
Originally Posted by MagicRat
I feel like it took a while to take effect, but this may be due to another factor. My tuning shop is out of town, and every time they've done work on the car I only really feel it when I get back to London and roads I know well. Cruising around my neighbourhood the night after the install, the car felt like it had turned into a 4.0 - only way I can describe it.
The mod that definitely felt like it did something immediately though was the pro tune I've had from Fabspeed via Cobb Accessport. This definitely improves 'throttle response', though I confess to being a little sceptical about the term (one can after all just press the pedal harder to get more response!). The engine feels cleaner revving now though, and the car seemed much faster on a section of country road I know well. Will post a dyno once I get it back into the shop. May just be that normal mode has turned into sport more on the throttle mapping but I don't think so...
Hey guys, very happy to see a collaborative effort in the GTS community to make an educated decision. Here is the dyno we did in house on a GTS in developing our new generation 991 Sport Headers with MagicRat's assistance/patience. These results were same dyno/car/operator within a 2-3 day span in our climate controlled facility
If there are any questions please know I am here to answer any you may have, and would love another GTS in the Fabspeed community
In the U.S., we don't hear too much about Kline. I didn't realized Kline makes sport headers for the 991 GTS. Please share the link and info.
I know Kline's exhaust has a very interesting sound, since the centers are made of Inconel.
Also, ensure the headers are designed specifically for the GTS. The GTS' OEM headers are very high flowing compared to the S, Fabspeed's first version of 991 headers weren't GTS specific so a loss in power was reported. Their latest version is GTS specific.
Hey guys, very happy to see a collaborative effort in the GTS community to make an educated decision. Here is the dyno we did in house on a GTS in developing our new generation 991 Sport Headers with MagicRat's assistance/patience. These results were same dyno/car/operator within a 2-3 day span in our climate controlled facility
If there are any questions please know I am here to answer any you may have, and would love another GTS in the Fabspeed community
Thanks John. Really appreciate your insights. I'd be in the US I won't hesitate a second. What do you think of ECU reset after changing headers and cats?
Thanks John. Really appreciate your insights. I'd be in the US I won't hesitate a second. What do you think of ECU reset after changing headers and cats?
My pleasure Don't let being in Europe stop you, we support our clients world wide. I was on the phone with some fellas in Lebanon and Australia this morning, and Magicrat is over in the UK. Personally Australia is on my bucket list, I need to see the V8 supercar races in person haha.
ECU reset is not necessary by any means with our Sport Headers, but there is certainly some untapped potential in the factory software that will become more apparent with increased exhaust flow to take advantage of. Software is always the last piece of the puzzle to maximize the potential of all the upgrades working to together.
07-05-2016, 01:20 PM
