GT4 - Unlocking the Power Potential!
#646
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The tuners can turn this off in the firmware so if you do get a reflash, you will be fine. if you run manifolds with cats, this is not a problem. The single biggest issue is that the Cargraphic manifolds don't have a post cat O2 sensor bung, only a pre-cat one. Therefore there is no place to put the post cat O2 sensors in the stream and what you do end up getting are a bunch of faults for the ECU's thinking that the post cat o2 sensors are broken, stuck open, etc. I have this issue on my car and while it's annoying and while i'm told it can be turned off, i need to resolve it this week and at least get that thing in the stream somehow. I'm still massaging the firmware from having race headers and no place to hang the O2s. I have other customers that are driving around with plenums and race headers and CELs but they don't care because they're grinning ear to ear with the power improvements.
#647
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You would know it immediately. You get a hard fault warning in red on the cluster and the car sounds like it's running on half the cylinders. Trust me...it sounds like it's broken. If you run the car out of gas on the race track and it stumbles more than once, it will also do this same exact thing so just beware, those of you that track and on the last session you try and stretch the fuel knowing that you may run out.
The tuners can turn this off in the firmware so if you do get a reflash, you will be fine. if you run manifolds with cats, this is not a problem. The single biggest issue is that the Cargraphic manifolds don't have a post cat O2 sensor bung, only a pre-cat one. Therefore there is no place to put the post cat O2 sensors in the stream and what you do end up getting are a bunch of faults for the ECU's thinking that the post cat o2 sensors are broken, stuck open, etc. I have this issue on my car and while it's annoying and while i'm told it can be turned off, i need to resolve it this week and at least get that thing in the stream somehow. I'm still massaging the firmware from having race headers and no place to hang the O2s. I have other customers that are driving around with plenums and race headers and CELs but they don't care because they're grinning ear to ear with the power improvements.
The tuners can turn this off in the firmware so if you do get a reflash, you will be fine. if you run manifolds with cats, this is not a problem. The single biggest issue is that the Cargraphic manifolds don't have a post cat O2 sensor bung, only a pre-cat one. Therefore there is no place to put the post cat O2 sensors in the stream and what you do end up getting are a bunch of faults for the ECU's thinking that the post cat o2 sensors are broken, stuck open, etc. I have this issue on my car and while it's annoying and while i'm told it can be turned off, i need to resolve it this week and at least get that thing in the stream somehow. I'm still massaging the firmware from having race headers and no place to hang the O2s. I have other customers that are driving around with plenums and race headers and CELs but they don't care because they're grinning ear to ear with the power improvements.
Thanks!
Maybe modifying the header with another O2 port/bung?
Not my case, but if you get CEL from Race header is there any adjustment from the ECU that could restrict performance?
Sent you the part number for the OEM manifolds via e-mail.....
#648
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Does anyone know if the Durometric works on the GT4 and can do the TB calibration?
#649
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Thanks for the response ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
As long as there is no detriment in power/no limp mode for not having cats, I might consider a race header. I don't want to mess with ECU reflashing just yet due to warranty issues. I'll just swap on the OEM header with new bolts if I do have a problem with the race header. My God this is a lot of potential incriminating evidence, I will delete these posts once you get back to me
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As long as there is no detriment in power/no limp mode for not having cats, I might consider a race header. I don't want to mess with ECU reflashing just yet due to warranty issues. I'll just swap on the OEM header with new bolts if I do have a problem with the race header. My God this is a lot of potential incriminating evidence, I will delete these posts once you get back to me
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#650
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Thanks for the response ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
As long as there is no detriment in power/no limp mode for not having cats, I might consider a race header. I don't want to mess with ECU reflashing just yet due to warranty issues. I'll just swap on the OEM header with new bolts if I do have a problem with the race header. My God this is a lot of potential incriminating evidence, I will delete these posts once you get back to me![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
As long as there is no detriment in power/no limp mode for not having cats, I might consider a race header. I don't want to mess with ECU reflashing just yet due to warranty issues. I'll just swap on the OEM header with new bolts if I do have a problem with the race header. My God this is a lot of potential incriminating evidence, I will delete these posts once you get back to me
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#651
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#652
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If your running catless, the post O2 sensor can be replaced with a dummy sensor which simulates a working one, thus fooling the ECU in thinking that the O2 sensor signal is normal.
#653
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My plan is to blow a hole in the OE PSE over axle pipe and put it in there at the appropriate distance to the pre cat sensor AND maybe install one of those pseudo cats that Fabspeed or Big Daddy's Garage sells so that i can rule out too many outside factors. I can say for certain that the mixtures results to something of a fatter nature after 1 to 2 road tests with these faults. A drive from work to home sets it off about 2 miles into the ride to work the next morning. It's less than 10 miles from here to there and once it does, the mixture goes fatter like most things do so that the motor runs cooler and is protected. I bet ignition timing comes down as well but i can't say for sure.
I don't know how updated they have gotten over recent months. I also haven't checked in a while BUT they did have this capability for the 987.1 and 987.2 cars that were run on Bosch and then Siemens.
Let me see how my short term fix goes but i think there's a good chance you wont like the outcome. When tested, it was deemed that the race manifolds cause the car to run significantly fatter after installation. I don't want to advocate drilling holes in the stock PSE axle pipe and welding in an O2 bung BUT if it can silence a CEL it's worth it. I hate to be the bearer of bad news but if you run race headers, you have to assume it's going to affect the mixture, mileage, exhaust tip color, etc and set off a CEL. Let me see which CELs go away and which stay.
I don't know how updated they have gotten over recent months. I also haven't checked in a while BUT they did have this capability for the 987.1 and 987.2 cars that were run on Bosch and then Siemens.
Let me see how my short term fix goes but i think there's a good chance you wont like the outcome. When tested, it was deemed that the race manifolds cause the car to run significantly fatter after installation. I don't want to advocate drilling holes in the stock PSE axle pipe and welding in an O2 bung BUT if it can silence a CEL it's worth it. I hate to be the bearer of bad news but if you run race headers, you have to assume it's going to affect the mixture, mileage, exhaust tip color, etc and set off a CEL. Let me see which CELs go away and which stay.
If you move the second O2 after the header you may run out of harness to reach any port on the exhaust system.....the ide of a Mini-cat could work but not sure how long those last.
#654
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Looks like the Cargraphic Cup and Race X muffler have middle pipes that have the post catalyst bung, so a combination of race header that has the pre catalyst bung, and one of those two gives a place to mount all four O2 sensors.
Last edited by d00d; 10-28-2017 at 11:20 AM.
#655
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Looks like the Cargraphic Cup and Race X muffler have middle pipes that have the post catalyst bung, so a combination of race header that has the pre catalyst bung, and one of those two gives a place to mount all four O2 sensors.
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2016 white/black GT4
2008 white/amaretto S8
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2016 white/black GT4
2008 white/amaretto S8
Well.....at least the 981 Cup exhaust system doesn't have it. I have that exhaust on my car.
#656
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I'll go with sport headers then ![surrender](https://rennlist.com/forums/graemlins/surrender.gif)
The cargraphic sport header has post cat O2 bung?
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The cargraphic sport header has post cat O2 bung?
#657
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Yes, both pre and post.
Last edited by d00d; 10-28-2017 at 11:21 AM.
#658
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Yeah, the picture on BGB's site is marked 987 and has a bung and flex section, where under GT4 on the Cargraphic site it has a bung but doesn't have the flex section.
Last edited by d00d; 10-28-2017 at 11:21 AM.
#660
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2.) Without a tune there's an 80% chance that you will get a CEL but I tell everyone that they should expect the CEL 100%. Some folks say they have not, Fabspeed reports not...I'm not refuting what they're saying but i'm a skeptic when it comes to how fickle these cars are and I can't believe that will fix it 100% because I've gotten calls from frustrated GT4 owners who had a dealership clear the CEL and had it return.
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Porsche Performance Specialist
John@Fabspeed.com
215-618-9796
Fabspeed Motorsport USA
155 Commerce Drive Fort Washington, PA 19034
www.Fabspeed.com