It’s only been about two weeks since Porsche announced that the next 718 Boxster and Cayman will get high-end combustion-powered variants, but in hindsight, this was inevitable. The customer base exists to sell a fossil fuel-burning mid-engined sports car alongside an electric one, and in limited volumes at a high enough margin, why not?
Of course, as soon as word got out, everyone started wondering just what engine these new models would use. Would it be a naturally aspirated screamer like the 718 Boxster GTS 4.0 uses, would it be a straight-up GT3 engine like in the 718 GT4 RS, would it be basically the same three-liter turbocharged flat-six as the base 911 Carrera? As Autocar reports, incoming combustion variants of the next Porsche 718 might use none of the above.
Instead, the new “top” 718s are expected to adopt the compliant T-Hybrid set-up introduced in the 911 Carrera GTS. Autocar understands this is because that set-up’s new flat six is 110mm shorter than the 911’s standard twin-turbo engine, which is crucial for the 718’s packaging.
Huh. Let’s unpack this rumor for a minute. The new Porsche 911 GTS T-Hybrid uses a 3.6-liter flat-six called the 9A3B6, a substantial redesign compared to the 9A2 evo engine offered with turbocharging in non-hybridized 911 Carrera models and naturally aspirated in the outgoing 718 Boxster and Cayman GTS 4.0. The big packaging draw of this engine is that it sits 4.33 inches or 110 mm lower than the 9A2 evo in order to accommodate hybrid power electronics packaged atop the engine in the 911 Carrera GTS T-Hybrid.
This line of thought begs the question: what platform will these combustion-powered “top” variants of the 718 use? As it stands, the outgoing 718 shares its MMB (short for Modularer Mittelmotor Baukasten) platform with the current 911, so it would make sense to reengineer it to be compliant with European GSR2 regulations mandating advanced driver assistance systems, including driver monitoring systems and intelligent speed assistance. It’s yet to be seen what platform the battery electric variant uses, but it would be surprising if it works out cheaper to reengineer the EV variant to accept combustion power than it would be to update the bones of the old 982 to be GSR2-compliant. If Porsche takes the latter path, the non-hybridized 9A2 Evo engine should fit just fine because it fits fine in the old 718 GTS 4.0.
Indeed, the big draws of the 9A3B6 engine, other than turbocharged power, are its emissions compliance and lightness. It’s designed to run at Lambda 1, or the stoichiometric air-fuel ratio of 14.7:1 parts of air to fuel, throughout its entire range of operating conditions. Compared to enriching the fuel-air mixture at wide-open throttle like most engines do, the Lambda 1 strategy cleans up the exhaust but has a lower envelope for detonation, or pinging. As a result, engines designed around this plan use less aggressive timing advancement, but Porsche seems to be making up for this with measures like added displacement and greater intercooler capacity. In addition, without the power electronics, the 9A3B6 is lighter than the 9A2 Evo, and lightness is good.
Of course, the big downside to using the 9A3B6 in the next combustion-powered 718 Boxster and Cayman is that it’s not currently available with a manual transmission, and the market has already spoken about its desire to row its own gears. Late-model high-end Porsches with manual transmissions typically pull a resale premium over their dual-clutch automatic counterparts, and given that high-end 718 buyers are looking for a smaller, more focused, more raw experience than the current 911, going two-pedal-only would be a miss despite the awe-inspiring power of the 9A3B6 and its T-Hybrid setup.
Still, with an expected relaunch date closer to the end of the decade, a lot could happen with next-generation combustion-powered 718 Boxster and Cayman development over the next few years. It’s possible a variant of the 9A3B6 could be used with a manual transmission, moving the Boxster closer to its roots as a mid-engined 911 sibling with a lower-output engine.
Top graphic image: Porsche
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Porsches and many new cars (to a lesser extent) have gotten so complex and costly that I find myself having much less interest in them than I did 10-20 years ago.
Ah, the new EU (and therefore all markets that piggyback off EU compliance) Lambda 1 regulation.
“As a result, engines designed around this plan use less aggressive timing advancement, but Porsche seems to be making up for this with measures like added displacement and greater intercooler capacity.”
I can imagine that some EU committee heard about fuel enrichment and decided to ban it because more fuel = more CO2. Not realising that turbo downsizing (everyone’s response to the current emissions regulations) only works if you use fuel to cool the exhaust valves, turbos and cats for the tiny percentage of time the car is under high load.
So now to keep peak power levels the same as before Lambda 1, and it’s associated reduction in power/capacity, all the engines have to become larger.
Big engines are inherently less efficient all the time. They’re also bigger and heavier, hugely so if you have to add cylinders to make up the capacity, which you will if you stick to the emissions sweet spot of about 500cc/cylinder. Imaging a GR Corolla with a 300bhp 4.0 V8 instead of the tiny three cylinder engine it has now (yes, I know to Americans that sounds great, but how are you going to get that engine to fit? And how is it going to handle afterwards?)
In summary: in order to meet Lambda 1 car makers have to spend hundreds of millions on new engine architecture, just to deliver cars that drive about the same as the ones we have now, but use more fuel.
Given the amount of effort used to achieve a full-spectrum Lambda 1 engine, it seems like Porsche would want this engine in much of its product line eventually. But a manual version? I’m not seeing it, mostly because the 9A3B6 is inextricably linked–not even a clutch–to the electric motor in the PDK transmission. And you can’t simply undo this by removing the hybrid components (battery-motor-transmission) because the 9A3B6 no longer has any accessory drive. It needs the 400V e-motor to operate.
Porsche might re-engineer this to create yet another engine type so that a manual transmission can be used, but since a ton of other changes were made to this engine to achieve Lambda 1 (variocam gone, dual to single turbo, dual to single intercoolers, dual to single hybrid exhaust, bucket tappets gone, crankshaft countershafts lightened) it’s not likely Porsche will send it back to the old ways.
The 9A3B6 actually has a decent induction note despite being turbocharged.
On the mid-engine cars I’d expect them to accentuate that further, especially on higher trims, given the exhaust noise hasn’t been much in the past 3+ years.
At the end of the day, the 9A3B6 is where they spent their R&D money. The amount of money put into ensuring a combustion chamber design will meet future requirements for a decade plus is real. It’s the most expensive part of engine development by a large margin. Porsche would look to leverage that work further.
No collab with Subaru? 😛
V4 diesel?
Oh wait its a fairly sensible choice.
Of course! They’re killing the vaguely attainable engines in favor of charging $200,000+ before markups on a GT whatever version. Line go UP!
Markups are gone. They started coming down in April 2024, and they were basically gone at the beginning of 2025, with VERY few market exceptions.
Anyone still paying them is simply lazy and not putting in effort when buying.
EDIT: Not just the 718 RSs, GT3s as well.
Yeah yeah, wake me up when they’re $70,000
*fucking dies*
Be honest with yourself, that’s inline with everyone expecting Porsche to make a Miata-priced competitor, or Ferrari to compete with the Corvette.
They never have, they never will. It’s not the market they address.
If you got $70K to spend, a fantastic 981 Boxster S is $50-55ish for a really clean one with all the right options in fantastic condition, and is all the Porsche anyone ever really needs. You can use damn near 100% of it on public roads, it’s not slow, sounds and handles great, and nice enough for a spouse to play ball.
I’m also being facetious. My next daily is going to be an EV (probably the iX3) and 5-10 years after that I’ll have a window to splurge on a weekend car. It’ll most certainly be the most Porsche I can get for whatever my budget is at that point, and I will enjoy it immensely.
I gotta say it like it is: You do not need a new daily.
Continuing to buy depreciating dailies is why most people never get the fun car. I am getting to the age (still “young”, but not as old as 20 years ago) where I can start to say I am watching people die continuing to buy dailies that don’t ultimately matter to them, and not getting what they actually want.
Keep existing daily in fine, reliable operating order. It is not expensive to do so, even for another 15 years.
Use that lack of depreciation, potentially finance (ugh) interest, etc. for… honestly, anything else. Retirement. IRA for kids. Furniture you’ll never get rid of. Or, perhaps, a non-depreciating fun car you and the SO can enjoy for 40+ more years.
What I desperately want is Porsche to yoink the GTi chassis and go nuts. That would be my ideal “entry level” Porsche.
Personally I’m hoping for the EV Cayman to come out so I can get a good lease deal on them
I’m looking forward to that car because it’s going to be good/receive a lot of acclaim and I can’t wait to see how hard the whining from MUH ICE crowd gets
I’ve had my name on the list at our local dealer’s for (checks calendar) 3 years for a Cayman EV. Not holding out a top of hope for that anymore.