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YOUR RESEARCHHeaders and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Replace power curve made it pretty squirrelly
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Performed · outcome unconfirmed · Original poster
One track day was inconclusive since it was raining until mid afternoon and the changed power curve made it pretty squirrelly on the track!
Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Leading evidence: 'Replace power curve made it pretty squirrelly' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace power curve made it pretty squirrelly' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Test seriously at the track and at some point soon
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Performed · outcome unconfirmed · Original poster
Yet to be tested seriously at the track and at some point soon, on the dyno.
Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Use twisted pair wire
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Performed · outcome unconfirmed
Front O2 sensors have slightly different cable sizing than the rears and I used twisted pair wire for the signal wires.
Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run rear cables around the suspension mounting points
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Suggestion
You can see in the video at the 11:00 minute mark that there is a little notch above the rear mid-pipe cat where I believe the wires would have come through instead of running the rear cables around the suspension mounting points.
Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Use pet
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Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Run rear cables around the suspension mounting points
No successful repair reported for this finding.
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Suggestion
You can see in the video at the 11:00 minute mark that there is a little notch above the rear mid-pipe cat where I believe the wires would have come through instead of running the rear cables around the suspension mounting points.
Headers and high flow cats - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Generation: 20261026T122219Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Yet to be tested seriously at the track and at some point soon, on the dyno. Sound is aggressive but not crazy loud. If you can keep your foot out of it, it purrs like a kitten. Punch it and you’ll hear a mutch larger cat! (Uh, cat, no pun intended).
It feels quite punchy at lower revs (3 to 4k), I’ll check out the curves with my tuner after the dyno. So far, I’m happy.
Nice video....hope to see your results soon. Were you getting a CEL with a ROW tune? This shouldn't be the case as you are basically in a ROW configuration....I hope anyway.
What exhaust component manufacturers did you use and why? Are your headers equal length tubes?
Were you not able to order euro o2 cables and just plug them in?
Great job on your project and posting your info on this much needed upgrade. I like your wire sleeving. Where did you source it? Car sounds great!
Key to not breaking header bolts is direct heat and an impact gun.
I installed Schnell equal length headers and Cicuit Werks 200 cell catted mid pipes to go with my Beluga Racing exhaust. Biggest decision points were Circuit Werks pipes seemed nicely built with the 200 cell cats and were relatively inexpensive and the Schnell headers take up a bit less room and do not come so close to the cooling lines on the passenger side.
Sound is great with a deep rumble at idle and cruising but when I give it the beans it really opens up and sounds amazing. Need to make a vid.
I painted mine with VMT Flameproof paint and wrapped them with DEI titanium exhaust wrap to try to control heat radiation.
I extended the car wire harness for my O2 sensors and did not touch the wires of the sensors as I was concerned about CELs. Front O2 sensors have slightly different cable sizing than the rears and I used twisted pair wire for the signal wires. Extending the car harness wires was a royal pain in the butt as there is not a lot or room to solder the extensions where the cables need cutting. I had removed the truck lid while installing my 987 intake and throttle body and sat in my trunk to extend the wires.
I have over 2000 miles on the car after doing this and my intake upgrades and have not had a single CEL related to the exhaust mods.
I don't think you can just buy the different O2 sensors because I believe the car harness is built with longer runs to reach the positions farther back. You can see in the video at the 11:00 minute mark that there is a little notch above the rear mid-pipe cat where I believe the wires would have come through instead of running the rear cables around the suspension mounting points. This is only my assumptions however.
I did not remove the aluminum braces and the sheetmetal cover to install mine.
Thanks, for your feedback. I was only hoping that there might be a "euro extension cord". Anyone that has done work on their 2.5 should be able to verify that the post cat O2 sensor lead comes out of the hole you spotted.
Dice and splice it is I guess.
Dave this is exactly what I was going on about.....only you made them. Where did you source the wiring harness connectors......cause you need that to connect each O2 sensor cable x4.
Obviously the other end can be cut off all old O2 sensor wires and plug right into the harness receptacles.
End connectors:
Bosch 1-928-403-453
Bosch 1-928-403-736
You need one of each for each extension.
To find these, web search is your friend.
Order some spares in case you mess one up.
DM
Haven’t had a chance to dyno the car yet. One track day was inconclusive since it was raining until mid afternoon and the changed power curve made it pretty squirrelly on the track! A dry end of day run was encouraging. It’s actually quite loud, even with the stock muffler! Seems to pull harder from 3k.
Eventually I did get a cel for the cats but it took quite a while. My tuner said that he can adjust for that.
The mesh sleeve was purchased at a local electronics supply store.
Is there any reason why these Bosch sensors wouldn't work for this? Seems to me, as long as there is enough length in the combined cables (OEM + Bosch Uni), there shouldn't be a problem, but I'm a complete novice at this.
Also, while I'm at it, I'm about to do the same exhaust as NewArt on my 01 Base. My cats are both toast, so this seems like a good time to do it. I've just been concerned that it won't solve my CEL issue due to eliminating the primary cats.
Will I have to take it in for some tweeking to the DME after the install?
https://www.boschautoparts.com/en/auto/oxygen-sensors/premium-oxygen-sensors-with-oe-smartlink
