Nope, no Fiesta in here! A Fiesta engine bay is below for your consideration. Not only is the engine oriented the wrong way, but it's not even the right engine. Oh, but the engine is so very right. The Ford Duratec (aka Mazda MZR) is an amazingly popular engine both in production (everything from the Mazdaspeed3 to the new Ford Transit Connect bakery van) and in motorsports (everything from Formula Atlantic, to half the Caterham 7s on the planet to, well, this monster). Given the orientation and the front differential I spotted under the intake manifold, I'd guess the drivetrain is based on the rally proven Escort/Sierra Cosworth.
There's a lot going on over here on the exhaust side. First, note the long-tube header. No shortie log manifold is going to support this kind of power, you need a smooth-flowing shape and proper pulse tuning on top of raw boost. Unfortunately, the heat wrap obscured a lot of details, like how the weight of that turbo is supported. This is no small detail when the turbo is this far from the engine (the long lever arm means a lot of torque on the manifold flange) and has to deal with the g-forces of a massive, 50-foot crossover jump.
It also isn't clear if its a single-scroll or twin-scroll turbo. Although a twin-scroll should give better boost response and a wider powerband, the single tube running up to the wastegate (sticking up behind the turbo) suggests its a single-scroll. A twin-scroll turbo would have separate collectors for cylinders 1 & 4 and for 2 & 3, with a wastegate tube coming off each collector. Before pencil pecker ran me out of town, Ericsson did let me know it was a Garett turbo, and that they ran a smaller turbo for X-games than they did for Pike's Peak. No surprise there, since the hillclimb is completely unrestricted, while X-games requires a 40 mm intake restrictor (you can see it just behind the lower blue turbo hose) allowing a little more power than the 37mm restrictor all Rally America open-class cars must run in normal stage rallies.
The two small stainless tubes running across the manifold are part of the anti-lag system. The valve at the front of these tubes (with the aluminum cap and blue banjo fitting on top) functions like a blow-off valve. Boost comes in from the hot side of the intercooler. When the driver lifts off the throttle, the valve opens, dumping that hot boost into the exhaust manifold. At the same time, the ECU goes stink rich and igition timing goes extremely retarded, sending raw fuel and belching flame into the manifold That raw fuel mixes with the air that was just introduced, goes kablooey, and spins the turbo, keeping it spooled up and ready for when foot hits firewall again. Of course, with the throttle closed, and no actual blow-off-valve venting boost, the spinning turbo has nowhere to pump air to. Some goes through that anti-lag valve, but a lot of it just stalls and falls back through the compressor - a.k.a. compressor surge. That horrendous chirping you heard on that Pike's Peak video? That's the resulting compressor surge.
Its easy to be distracted by all the turbos and plumbing over here, but there's a big, very important detail hiding in plain sight. Notice that conical, cast-aluminum manifold right over the exhaust manifold flange? Its a water manifold, collecting coolant as it exits the four individual coolant outlets over each combustion chamber. Look closely at your Ford Focus, Mazda MX-5, or Mercury Mariner, all of which have this same engine, and you won't see these coolant outlets. Ericsson said his early efforts with the Duratec resulted in a series of mechanical failures of the cylinder head itself, so he had Motor Design Sweden make a stonger one. The MDS head has a 15mm thicker deck and more material around the combustion chambers, plus the improved coolant flow form the four outlets which helps keep the hottest parts of the head from reaching structurally critical temperarures.
Natually, if you're going to build a race head, you do more than make it stronger. The head also features ports that are larger, straighter, and higher in the head (Duratec/MZR heads are known to have very good ports from the factory, so this probably wouldn't have been enough to motivate a new casting all by itself), and leaves room for bigger valves (as big as 37mm intake/33mm exhaust, up from 35/30 on the stock head). Around the camshafts, there is additional clearance for high-lift cams, and the lifter buckets are substantially larger (36mm on the intake, 35 on the exhaust side, both up from the stock 31mm), allowing more aggressive opening and closing ramps without the cam lobe wiping off the end of the bucket.
While we're noticing things in this picture, noice which way that coolant manifold points. It goes backward, down the transmission tunnel..
Look in the rear window, and this is what you'll find. Air gets sucked in two massive rear window scoops and dumped into the rear hatch. At the back is the radiator, with a suction fan on the back pulling air through, and a nitrous spray bar on the front to throw an extra chill on things. In the middle of the hatch is an oil cooler. There is no natural air flow going through it, so a large fan does all the work. The giant metal can in the foreground is the engine's oil tank. Naturally, it's dry sumped.
| With all the fluid cooling in the back, the front is all intercooler. In the foreground is what appears to be just the huge blow-off valve you'd need to prevent all that compressor surge chirping, but Eriksson has it set up only as a safety valve to blow off in the case of wild overboost or backfire. |
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Additional safety is provided by this pressure relief valve on the intake manifold. |
The intake side is also busy with details. First, and most difficult to spot, is the fact that the intake runners are spaced farther apart than a stock Duratec/MZR head. The production intake ports are surprisingly large and high, but the #1 and #4 runners angle inward slightly toward the center. The Olsbergs head has four identical ports for perfectly even flow distribution.
The intake manifold consists of individual Jenvey throttle bodies fed by a plenum of Olsbergs' own design. The three cars at X-Games had slightly different plenums, each a different stage in the evolution of the design. This one is the most recent evolution. To ensure even distribution into all four runners, the cold-side intercooler pipe forks and feeds into two inlets in the bottom of the plenum.
In engines with extremely-high intake air flow rates, it often helps to move the injectors farther upstream to get better atomization. As is common practice on ludicrously high-output engines, Olsbergs' injectors are across the plenum from the runners, giving the fuel maximum time to mix with the air charge and aiming the fuel directly down the runner so less of it gets stuck on the port walls.
The four conspicuous red banjo bolts feeding braided lines into the top of each port are actually vacuum lines. With individual throttle bodies there is never vacuum in the plenum. Instead, vacuum is collected before the throttles at each port, and fed into the conspicuous distribution block. From there, the vacuum signal goes across to the anti-lag valve and also to a small accumulator chamber just out of frame to the right. Another line goes from this chamber to the diaphragm just behind the throttle cable (the red doohicky just behind the vacuum block). The diaphragm pulls the throttle back open slighly, helping send the fuel and fire into the exhaust manifold to feed the anti-lag.
So, thanks to needle dick and his power trip, that's all I've figured out so far. Wanna know more? Wanna know something specific? Leave your questions in the comments section and I'll update the story as I get more info. Updates will be in different colors, so you can find the new stuff easily.
-Dave Coleman