12,000 rpm air-cooled Porsche 911 upgrade from Swindon Powertrain | CAR Magazine

12,000 rpm air-cooled Porsche 911 upgrade from Swindon Powertrain

Published: 05 October 2023 Updated: 05 October 2023

► Porsche 911 gets a 24-valve air-cooled head
► Swindon Powertrain spins the flat-six to 12,000 rpm
► Synchronised precision is pure poetry for M64 owners’ ears

The air-cooled Porsche 911 wasn’t short of performance by the time the 964 and 993 were on sale. Yet on National Poetry Day, Swindon Powertrain has chosen to release a modification that remixes the classic flat-six soundtrack and makes it sing.

Is there rhyme or reason to this innovation? Let’s find out…

Swindon Powertrain M64 24V head for air-cooled 911s

New heart for an old boxer

Another change in temperature
Air cooling, autumn falls like morning dew
Familiar scenes shift, colour and sound
The same orbit, same cycles, renewed

Multiplied, the magic works
In a roundabout display
Six, twelve and twenty-four
A dance repeats in 4/6 time

Breathing deep, the dancer’s timing
Becomes a blur, organic curves
Recognise this shape so timeless
Remixed in ways as yet unheard

Morning’s bark, the trumpets sing
Reveille in aluminium
Valves so fast, the pitch increases
Still harmony, remains complete

Grounded planes bequeath their spirit
Lightness gives dreams flight
Spring yet to come, pressure decreases
Freedom to run, more room to breathe

Zoom in close, magician’s secrets
Use your head, and close your eyes
Twice the mouths to sing these praises
Twice the mouths, that now imbibe

Sixty-six percent more volume
Forty percent more to inhale
Yet this gluttony, not wasted
Lighter, leaner, optimised

Thirty-thousand pounds is offered
Seven point seven pounds are saved
Porsche’s art as yet unfinished
Reborn upon Swindon’s lathes

Classic heart of 911, chambers beat the same
But valves, doubled, turn much faster
Twelve-thousand RPM, a pipe-dream?
Magic, yes, but there’s no trick

Circles within circles battle
Slice of pi and wasted space
Smaller circles, increase volume
911’s increased pace

Swindon Powertrain M64 24V head for air-cooled 911s

Smaller, less work, rockers relax
Though the beat is rising still
Past the limits of the ‘90s
Classic Porsche, modern thrill

ASMR, an air-cooled tingle
As the old song changes still
964 to twenty four
993 may join as well

As the seasons cycle faster
Age, like autumn, cools the air
But breaths deeper, shed the leaves of summer
Rebirth is just a spark away

Orbits, cycles, ever quicker
Timing tailored by the past
Artisans still reinventing
Engineers rekindle lust

A 911 like no other
Elder statesman of the breed
Purity of air-cooled boxer
Fighting with a young heart’s speed

24V air-cooled Porsche cylinder head upgrade

For those of you who would rather skip the poetry, the details are pretty straightforward. For £29,950 ex. VAT and fitting costs, Swindon Powertrain’s Formula 1 and BTCC-honed CNC machines been put to work on some aptly-named A356 aluminium – creating a 24-valve upgrade for the M64 flat-six used in the 964 and 993 generations of Porsche 911.

By using four valves, lighter springs can be used reducing the load on the rockers, and a greater cylinder area used for breathing – exhaust flow can be increased by up to 66%, while intake is boosted by 40% depending on application. Bore diameter from 95 to 102.7mm is supported, and the comprehensive package includes titanium valves, cam and timing gear covers. An option to retain the Porsche’s factory power steering is available, and upgraded pistons and other internals are offered should you want to take full advantage of the improved breathing.

Swindon Powertrain M64 24V head for air-cooled 911s

That advantage is most evident in the upgraded rev limits of the 24V M64. Testing has revealed an F1-like 12,000 RPM potential, suggesting not only a faster classic 911, but one that sounds like little else you’ll encounter on the road.

Swindon Powertrain may not have the mainstream profile of many 911 tuners, but their bespoke EV conversions and powertrain packages have reached cars as diverse as the classic Mini and the timelessly beautiful W113 Mercedes-Benz SL ‘Pagoda’ by Everatti (who also created an electric Porsche 964).

24V air-cooled 911s? Is this a precedent?

Sort of – Porsche used four-valve technology on the original Type 935, but with water-cooled heads, the same technique was deployed in the 959 and 911 GT1 (993) before the 911 adopted fully water-cooled engines. There have been many experiments, but Swindon’s package offers a relatively inexpensive route to a Group C-style soundtrack or, indeed, something rather different again.

By Richard Kilpatrick

Used cars editor. Questionable taste in cars, music and hairstyles. Wears a lot of black