Episode 6: Intake Engineering, 8K RPM Development & Real-World Testing (M96/M97)

We just released Episode 6 of the Slakker Porsche Podcast , and this one is heavily driven by questions from the community. 👉 Watch / listen here: Link - Episode 6 | Porsche 996 & 997 Intake Engineering, High RPM Builds & Real-World Testing The main focus of the episode is what it actually takes to safely rev M96 and M97 engines past 8,000 RPM - not just from a parts standpoint, but from an engineering and testing perspective. Topics covered include: Porsche intake design, runner length, resonance tuning, and intake flaps Why some aftermarket intakes lose power despite flowing more air Valve control at high RPM, including an overview of our 8K valve spring package Camshaft upgrades and the supporting mods that make them effective Real-world drive testing and the kinds of issues that show up Break-in and long-term maintenance for 4.1L builds (street vs track) Cold starts, warm-up habits, short trips, and fuel octane considerations 4.1L behavior in Tiptronic cars Engine scoring: what it really means over time Where we�re headed next in development, including future intake work This episode is more about understanding the system than chasing peak numbers, and a lot of it centers on respecting Porsche�s OEM engineering while carefully extending its limits. Many of the questions in this episode actually came from Rennlist threads, so the feedback loop has been really valuable.

Good video. Appreciate the details you shared and look forward to what you develop on intake improvements. Out of curiosity, what plenum and throttle body do you typically run? Also have a question for you on how different exhaust components will effect your numbers such as running equal length headers vs factory headers, and 200, 100, and catless pipes vs factory cats? Are there any more improvements that can be gained in your numbers from exhaust improvements or do you already include exhaust improvements in your testing and published numbers? Thanks!

Thank you for all the details with this episodes. The one thing that I cannot get my head around, however, is how does someone in Australia plan for a rebuild. If you're constantly tweaking, changing how you are doing things, re-writing the ECU, changing hardware etc.. how does one decide to go the Slakker route when there's seems to be no constant. Then to my next point, that would be there's not been a lot of testing to know what sort of longevity there would be. Manufacturers will doing 100,000s testing miles/dynos etc... to ensure longevity. Being so far away the 2 yeas unlimited warranty would be next to useless to me. Note : this isn't a complaint. emails/post often come across poorly so please don't take it that way

Good video great progress much appreciated

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I have an LN 3.8 in Australia, it involves. Shipping Taxes and cubic dollars. If you want to pay to play you can. Having spoken to you out of forum. You know quite a bit..

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We use a plenum that looks stock externally, but it�s machined for the 82mm GT3 throttle body bolt pattern. On the exhaust side, we�ve seen solid gains going from factory cats to either 200-cell or catless � those two test very similarly on our setup. The factory exhaust manifolds are actually pretty well tuned for scavenging, so we haven�t seen much additional gain from header swaps alone. Totally fair questions � and I appreciate you framing it the way you did. At this point we�re focused on the US and Canada. We have done one Australian race engine at Hartech�s request, but instead of shipping the customer�s engine, we sourced a core locally and built it here. The biggest hurdle ended up being wideband vs narrowband O2 differences, so we had to do some logging and remote tuning to get everything fully dialed in. As for the bigger point: Slakker exists because this is what I want to spend my retirement doing � working in an engine development lab dedicated to the Porsche 9X6 / 9X7 platform. That means we�ll always be searching for way to improve reliability and performance� it�s literally in our DNA. That said, we�re not �winging it.� We start with the 20+ years of Porsche development, then figure out how to apply/backdate proven OEM-level ideas. Hartech�s closed-deck cylinder design is essentially a Mezger-style solution. Our cam profiles are very GT3-like, the upgraded 9X7 valves are the same size as 991.1S intake valves, and our spring profiles are based on Cup car specs. None of that eliminates risk entirely, but it does substantially reduce it. Lastly, our full stage 2 upgrade package is aimed at early adopters. For those that want to substantially increase reliability with a hardened endurance racing engine design while bumping up displacement enough to make the power seem effortless, the base 4.1L that Hartech designed been a proven winner of multiple endurance racing series and is a ton of fun.

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indeed. Can always learn more. and if money allows I'd pony up for a 4.1 at some point in the future. I've discovered another LN engine in Botany. 997.1 that does challenge bathurst regularly it seems. Not sure if there's any Hartech's in Sydney/ Australia. Suspect there is.. but not aware.

Thanks for sharing your findings regarding the factory headers, Slakker. That�s really quite surprising.

All fascinating stuff. So lets attempt to tally up a 3.6 to 4.1 and 4.5 build to explain for estinated cumulative gains. Please feel free to correct my numbers I am just spitballing. 395 HP 1. Bore 3.6 to 4.1: ~45 2. Headwork/GT3 Throttle Body/Plenum/Tune: ~20 3. 200 cell cats: ~10 4. Upgraded headers: ~0 425 1. Bore 3.6 to 4.1: ~45 2. Headwork/GT3 Throttle body/Plenum/Tune: ~20 3. 200 cell cats: ~10 4. Upgraded headers: ~0 5. Upgraded Cams: ~10 6. Upgraded Springs for higher rev: ~10 7. Upgraded intake Manifold: ~10 450 1. Bore 3.6 to 4.5: ~70 2. Headwork/GT3 Throttle body/Plenum/Tune: ~20 3. 200 cell cats: ~10 4. Upgraded headers: ~0 5. Upgraded Cams: ~10 6. Upgraded Springs for higher rev: ~10 7. Upgraded intake Manifold: ~10 Corrections are welcome. As I mentioned before, I am just spitballing.

WTH would you want to rev above 8K? Asking for a friend.

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Beats me but i do it every 2.12ish minutes when lapping on the back straight at Watkins Glen, 144mph in 4th. The exhaust noises the car makes at that rpm r terrible.

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If you installed high performance Schrick custom cams with a higher rpm power band + tuning and other ancillary parts/work ,,,? Or already had a gt3ish mezger that likes the revs and installed the cams..? I'm told those cams (kits like the 280�/272� or 300�/292�) especially in a Mezger, gives it a nice boost all around with a useful higher redline for those long hard pulls up to braking point.

Sure, it would be fun to have a 8k reving 450 hp M96 in a 996. I know the straights i would want it at every track i have driven. For sure, 450 at 8k is an incredible amount of power in a lightweight car w/o nannies. It would surpass the 996 GT2 as the new "widow maker". The only recomendation I would have is to get sticky tires and make sure every owner gets driving lessons to learn how to drive and control a 996 without modern nannies.

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Must be just awful. I imagine you hate it every time.