What Will You Need To Do To Stick Porsche's New Flat-Four Into An Old Volkswagen?

When I first heard that Porsche was developing their first new production flat-four engine since the 356 era, I was understandably and visibly aroused. But not for any rational reasons; mostly because for me (and a good number of fellow loons) a flat-four anything is something that should be shoved in the ass of an old Beetle.


An opposed-four cylinder engine is, of course, very important emotionally and historically to Porsche. Porsche as a company was born from the also Porsche-designed Volkswagen Type I flat-four engine, modified to become the 356 engine, which was the powerhouse that Porsche rode to global notoriety.

So now that Porsche is making cars with flat-fours that regular (well, wealthy-regular) people can buy, the only rational question to ask is “How can I cram one of those into my old Beetle/Bus/Ghia/Thing/old air-cooled whatever?

There’s something so gloriously right about upgrading an old Volkswagen into a modern, terrifyingly fast sleeper with a Porsche flat-four. Sure, plenty of brilliant loons are doing very similar things now with Subaru flat-fours (the only remaining maker of mainstream automotive flat-fours until just now), but having a Porsche-designed-and-built engine in the car is just conceptually lovelier.

Also, with a 300 HP Porsche engine in an old VW, you’ll probably want to upgrade the brakes, suspension, seat belts, tires/wheels, and pretty much everything else, unless your plan is to make the most delightful suicide machine known to man.


So, let’s do a quick rough rundown of what’s going to need to happen to make this work!

You’ll need to flip it around


The 718 Boxster and 718 Cayman that Porsche is building these engines for are both mid-engine designs. The VWs an ambitious kook is most likely to want to put these in are rear-engined. That means the drivetrain needs to be flipped 180°, and needs to drive the wheels in the opposite direction, unless you want a car with one forward gear and a five (or more)-speed reverse.

So what are you going to do? Luckily, the VW world has been doing this for a while. First, in the opposite direction, it’s long been a practice to flip the guts of a VW transaxle to get the wheels going the opposite way, so you can build mid-engine VW-powered cars, like the little Formula Vee racecars or, even the very first Porsche.


We want to go the opposite way, and happily the Subaru-powered VW pioneers have already figured this out, since a longitudinal FWD Subaru engine is basically the same as a mid-engine Porsche setup, at least as far as rotating gears are concerned. That’s why I think you could use one of the many Subaru-to-VW transaxle options already out there.


Also a good thing: many of the Subaru-to-VW transaxles are built (or can be built) to handle the 300 HP/280 lb-ft (200 Nrp) that the 718 engine puts out. Incredibly, a stock VW transaxle is often said to be good for up to 250 HP, but if you’re going through all this cost and effort, you may as well get something beefier, and with more than four gears.

You’ll need an adapter plate

Now, I haven’t actually seen what the 718 engine looks like where it meets the transmission, but my guess is the bolt pattern and everything are not an exact match to the old VW air-cooled standard. So, you’ll need to have an adapter plate CNC’d out of aluminum. I’m sure once this gets nice and popular, you’ll just be able to order one.


You’ll need to cool it

Image from this guy, who put an Alfa engine in his Super Beetle

Since the new engine keeps cool with Evian instead of cheap, plentiful air, you’ll need to rig up a radiator and coolant tank, hoses, etc. At first glance, I’d think the Porsche has an advantage over the Subaru here, as the hardware used in the 718s should work fairly well on your old Beetle or Bus; the radiator is up front, and the engine’s still a ways back in the Porsche, so the water pump and hoses are designed already for a fairly long trip.

I’m sure there’s many ways to design this independently, but if you somehow have this mythical wrecked or stolen 718 to get the drivetrain out of, be sure to get all the cooling system bits, too.


Of course, that’s assuming you’ll be mounting the radiator up front. I mean, you could, and if you’re using a Super Beetle they have those valences that are already vented, or in a bus you could get one of those front-mounted radiators from the late Brazilian water cooled buses, but you could also mount the radiator (or radiators) at the rear, with ducting to catch airflow as it goes over the top of the car, like the Beetle’s original cooling system used.


You could sacrifice the rear luggage well for the radiator and intercooler, and pull air from some sort of scoops, possibly pulling air from below?

You’ll need a whole new exhaust system

Looking at these pictures of the exhaust setup on the 718s, it’s clear that it’s designed to use the space over the transaxle. Since we’ll be flipping our Porsche flat-fours backwards to fit into our Country Buggies, you’ll need to have a new exhaust system made, unless you want an intestinal-looking set of pipes hanging out of the back of your car for a foot and a half.


I don’t think this is necessarily rocket science, and I’m sure any shop used to making Baja headers and stuff can likely put together something that works. The big trick will be packaging those two mufflers and the catalytic converter. Maybe in the fenders?


There will probably be cutting involved

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I haven’t seen actual size dimensions of the new engine, and while they seem like compact units, I’m sure there will be some cutting and welding involved to get everything to fit.

I’m just not sure how much. Will these engines require sacrificing the rear luggage well? Will it mean an unsightly hump in the bed of your Type II pickup? I’m just not sure yet.


I’m probably not going to do it, but I hope someone does

Let’s be honest here: I’m not likely to have the money to just buy one of these engines, and I probably only have enough skill to tear everything apart before I realize what a horrible, expensive mistake I’ve made. But I’m an idiot.


For people who have already done Subaru swaps, I don’t think getting these new flat-fours in old VWs will be that much different, and I’m sure somebody is going to do it. That excites me.

Honestly, for the most part, follow what the Subaru swap community has done. There’s lots of information out there, like this nice long video here:

If any of you end up doing this, let me know so I can cover the crap out of it and beg you to let me drive it. Just a little. An 1800 lb Beetle with a 300 HP Porsche engine in back will be certifiably bonkers, so I’ll go easy, for the sake of my pants and my child retaining a father.


UPDATE: Holy crap, I forgot all about the electronic aspects here. The ECUs and all of the no-doubt considerable issues those will bring. So, you know, don’t forget that when you give this a shot!

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About the author

Jason Torchinsky

Senior Editor, Jalopnik • Running: 1973 VW Beetle, 2006 Scion xB, 1990 Nissan Pao, 1991 Yugo GV Plus • Not-so-running: 1973 Reliant Scimitar, 1977 Dodge Tioga RV (also, buy my book!)