Making the 911 that Porsche were too sensible to consider

This is a longer post from 911uk which was a response to "WTF are you doing you idiot?"

Chasing the noise.

I was 22-23 when the Porsche GT3 was announced, and at the time I read all of the car magazines from cover to cover - this was before the Internet changed the publishing landscape and there was a wealth of tests, driving stories and reviews.

I read them all, and from the standpoint of an alcoholic architecture student who never opened a letter if it had a window in the front they were as relevant to my life as the space ships in the science fiction novels that I also devoured. However, the stories stuck with me over the years as my situation changed, and a series of seemingly impossible challenges fell one after another - I gave up smoking, then drinking, both things that an earlier me had considered to be literally impossible.

I did better at work, life became more stable and then at the age of 40, reviews of that first GT3 still in my mind, I bought a 911 of my own.

Percy was not the car I intended on buying, nor was he the car that would ever win favor with the inchoate but inescapable quorum of car enthusiasts - as despite his manual gearbox, LSD, hard-shell seats and sports exhaust he also featured the ultimate accessory of hair-dressers the world over, the convertible roof.

I didn’t care, he was a tremendous little car and accomplished a life goal, and I concentrated on bringing his condition up to a point that was arguably better than new - challenging given that he was 20 years old and had clearly had a number of owners who were less committed than I was to attending to squeaky bushes, worn coffin arms and so forth.

I also worked on how I fit into the car - changing the wheel, removing the lower console, having the seat modified until we gelled together in a way that I simply could not with a standard car. This was to become something of a theme - and soon Percy was riding on significantly upgraded suspension, newer, larger wheels, was resplendent in a new coat of paint and had a new mohair roof with a heated glass window replacing the original, and largely opaque plastic one.

By this point I’d been thinking about the engine - a sea change for Porsche in that it was their first water cooled engine for the 911, and like all most initial offerings whilst it had it’s strengths it also had it’s weaknesses. I decided on a prophylactic rebuild that would remove the weaknesses (which by this point, 20 years in, were quite well understood) whilst building on its strengths.

At the back of my mind, as ever, was the mighty GT3 and it’s Mezger engine - a unit forged in the Porsche Motorsport program, a direct relation of the Le Mans unit from the GT1 and famously carrying part numbers that demonstrated it’s heart was shared with the 964 (at least for the earliest units). 3.6 litres, 360 horsepower and 8,000 rpm in the gears, all accompanied by a spine tingling shriek that sounded like nothing else on four wheels.

For me the sensations of Motorsport always started with the noise - the rising intonation followed by a brief pause, then a further escalating shriek of the cars running on the straight followed by what to me was always the most intoxicating sound - the driver prepares the car for a corner, engine barking in repeated short bursts whilst they change down through the gears. That whap-whap-whap almost like a super-bike engine revving on the starting grid. It was the first thing that struck you as you walked into a racing circuit, then the smell of hot motor-oil competing with that of the doughnut stands, and finally the sight of the cars themselves, primary colours of sponsors logos, flaring brake discs and flaming exhausts. But ever present, the noise- spine tingling howls punctuated by staccato barks, the defining aural signature of the sport.

How could I miss the opportunity to bring some of that to Percy, the little silver bath-tub with his hairdressers roof?

Enter Mike, a man who has been involved in Motorsport for his entire life, with multiple championship winning engines having emerged from his modest workshop.

What started out as a project that wished simply to lose none of the spark and zing of the 3.4 M96 engine soon spiraled, the replacement of weak parts meant, of course, an opportunity to do better - we took the Porsche X51 version of the same engine as an inspiration as much as we did the Mezger, but what soon emerged was wholly our own. Then Martin joined the project, a fellow enthusiast who shared our passion for making the ill-favored M96 what it could have been, if the 996 Cup had been run with X51 engines rather than the race-derived Mezger.

In creating our alternate history we soon accrued a great deal of knowledge, much of it directly in proportion to the expertise and inclusive nature of the Porsche community, and the engines themselves began to take shape.

Mike was forever the voice of sanity, reining back some of our more “because race-car” thoughts, whilst giving full approval to our more sensible suggestions.

We steadily designed and made parts, sometimes multiple takes on a single unit - three intake cams, two exhaust, two different tappet chests, modern iterations on once-produced X51 specific parts such as the engines iconic additional scavenge pump and “towel rail” return line. I was particularly entertained by the repurposing of a bearing that normally sees duty in a helicopters main rotating assembly, which was soon followed by parts appropriated from the E60 V10 engine.

Through it all ran the desire for that noise, to me the epitome of racing, the sound of an engine born to rev, a weightless, effortless bark twinned with a basso growl that rapidly becomes a searing howl before dropping down to do it all again.

We’re still a long way from the finish line, two short blocks wait on the shelf at Hartech with their new cylinders fitted whilst we finish off the critical aspects of the intake system, pistons and exhaust. But we’ve crossed the mid-point now, the design is finalized as a strategy, with only tactical decisions to be made as we make progress to the engine dyno.

What will our pair of engines make, in the end? My 3.7 and Martins 3.9 will ultimately have to tell that story in Mikes dyno room, but whatever the final figures, they’ll both make the noise.