After much deliberation, looking at a ton of engines, talking to lots of motor and electronics folks and almost making a deal that I then had to back out of, I’ve finally purchased an engine. As it happens with these kinds of things, the engine I bought basically was under my nose ready to purchased from the time I first started looking for engines and transmissions, but I had to take my own long path to get there. Thankfully, I again learned a lot though and I think I got a pretty decent deal on it.
So what did I get? I got a 2004 Porsche GT3 engine out of the same car as the transmission. It’s got about 17k miles on it and I was very comfortable purchasing this engine, since the vendor (Speedy’s in Nashville, TN) was easy to deal with when we did the deal on the transmission. The final engine transaction was simple, shipment was quick and since I knew the transmission was in great shape, I was very comfortable that the motor would be in the same great shape. I also was able to get the clutch from the car as part of the deal, so that’s another part I don’t have to source new.
But onto the meat of it: why this engine? Let me start by doing a little Porsche engine history. All Porsche 911 engines from 1965 onwards are what’s called “flat-6” engines, where there are three cylinders on each side laying flat opposite each other. It’s also referred to as “boxer” motor and it’s where the Porsche Boxster derives its name. Until 1998, all of these engines were fully air-cooled and that last air cooled generation, the 993, is pictured at right. While air cooling was a popular design used in many cars like the Volkswagen Beetle, by the 1990’s it was a fairly unusual setup. Fortunately for Porsche, their air cooled block had an excellent reputation with a lineage that traces back to the same basic design from the 1980’s. It’s won many races, was at the base of all 911s and was an all-around great block that everyone loves. Beyond being race-proven, durable, easy to tune and fairly simple, a major reason why it was liked so much was the air cooling makes an engine and car much lighter, because it doesn’t need all the plumbing for cooling with water. Unfortunately, the big disadvantage is as engines produce more power and thus more heat, cooling them turns into an ever greater challenge. At some point, cooling by air just becomes impossible for a street legal car that needs to survive conditions like Death Valley, especially once you add forced induction (turbos) in the mix.
Porsche therefore decided that it was necessary, rightly so, to move to water-cooled engines for their car and developed a series of engines called the M96 and M97 to fit into the 996 generation of Porsches (1998-2005), pictured right. These were their first fully water cooled engine blocks, a fresh ground-up design, and these engines were fitted into all 1998-2009 base Carrera and Carrera S models.
Since this was Porsche’s first major foray into water cooling technology, the engines turned out to be somewhat complex – especially so if compared to their predecessor – and did not have a bulletproof reputation. It was a decent engine for your grocery shopper or commuting i-banker buying a Carrera or Carrera S, the bulk of Porsche’s audience, but not for higher end powerful or club racer models. Porsche therefore did not deploy this base engine block in those cars. Instead, the street-legal almost-race cars like the GT3 and forced induction Turbo, Turbo S and GT2 models all retained the old air-cooled block, but with the addition of water-cooled heads. They were never switched over to the M97 engine and never will be, completely skipping this block. Instead, the plan is to move these over once the second generation water-cooled block has proven itself.
That new block is the MA.101 and MA.102 series of engines. From 2006-2008, the first generation 997 ran the same engine as the 996 version. In fact, many pieces on the whole care are interchangeable between these two generations. But starting in 2009, the refreshed 997 generation Carrera and Carrera S models had the new engines. The larger Carrera S 3.6-liter MA.101 is supposed to be the 911 engine of the future and all Porsches going forward, higher end included, will be based on this block. It contains 40% fewer parts than the previous block and has so far proven to be very reliable apparently, producing 385 HP in the Carrera S. As the 997 starts to get replaced from 2012 onwards with the 991 series of Porsches, this will be the single base engine for them all supposedly.
Since this is a modern engine and Porsche’s engine of the future, I wanted to put that in the SLC. What’s most unique and modern about it is that it uses a technology called direct injection (DI). It’s often referred to as Direct Fuel Injection (DFI) and Gasoline Direct Injection (GDI) as well. The basic principle is that gasoline is injected into each cylinder individually and under very high pressure, thus making for a more efficient burn.
Unfortunately this did not work out. Here’s why. First, the electronics in a Porsche are all encrypted and if you don’t run the full suite of sensors, ECU, wiring, ignition, key fob, etc. all the way through the dashboard (or figure out how to fake them out), you won’t get the engine to start. You therefore need to get an aftermarket ECU, which is not at all a problem, as there are quite a lot of manufacturers doing anything from ECU upgrades for street cars to full on race car solutions for professional teams. The problem is that DI is a very new technology and with the exception of one manufacturer (Cosworth/Pectel), none of the major suppliers can run a DI engine yet. Cosworth’s DI system is expensive for the hardware and takes a long time to tune, so this turned into the second effectively insurmountable problem.
I wish I had known this earlier. I had gotten some input from a number of ECU vendors’ technical representatives and they said “no problem”, so I went onwards with my search. I spent a fair amount of time sourcing an MA.101 engine and finally had found one with only 2000 miles on it. I had a contract in hand and was close to signing it when I got in touch with an (the?) expert on aftermarket engine and race car electronics, Neel Vasavada from Apex Speed Technology. His input: you’re crazy (nicely), we can do it for you, you won’t gain much with it, you’re crazy (again nicely), it’ll cost you, we can do it, but I recommend against it. Ok, point taken, I didn’t buy the engine.
So remember how I said the high-strung Porsche 996 and 997’s are the air cooled block, but water cooled heads? I went back and made a deal on the block from the 2004 GT3 that gave me my transmission, because I knew this was the old air-cooled block, but with water-cooled heads. In stock form, it’s a naturally aspirated 3.6-liter engine with a redline around 8200-8400 RPM. To this day, it’s the base of Porsche’s race car efforts in the the GT3 series, run at races like the 24 Hours of LeMans and ALMS. It’s consequently fairly easily tunable to 500 HP by changing the crankshaft and pistons, but I’m not fully sure that’s necessary in a 2200 lbs car, at least initially. It’s also got a dry-sump oiling system vs. wet-sump, but that’s a topic for another day.
What I think will be most fun about this engine is the noise. At a high redline for a street car, it should be quite the high-pitched symphony coming from behind me. In my opinion – and opinions greatly differ on this – I’m much more fond of this than a growly and ubiquitous V8. But that’s just personal preference and there are some great V8 SLCs being built. I’m just sticking to my German roots and being a Porsche nerd I guess.
Oh, and it runs better with high-end electronics. Hint, hint… 🙂