@edsnova I like the SOHC, too. I just heard that Greg is picking up my motor from John to install it, so maybe now is a good time to start listing specs on the engine. I haven't got the fine detail sheet rom John yet, but I have the invoice and my notes from discussions with John and Jeremy at Outfront, so here it goes.
It's the last iteration of the 2.5 SOHC engine code EJ253 sold up through 2011 in the US. In stock trim, with cats, running through all pollution controls, full muffler, and air box on Subaru engine management the engine makes ~170hp @6200 and ~165ft/lb torque 4200rpm. The torque curve is pretty much flat from 3500 to 5200rpm. Redline is 7,000 max, but a 6-6500 shift point for maximum acceleration seems best. (there was a variable vale train version that bumped hp 5 and torque 10 on the same block and head casting) Remember this curve the we get to the transmission ratios in a later post on its specs. This seemed like a great place to start because I wanted two things in my coupe so I could drive it year round: heat and AC.
Talking to John there were lots of options available, including stroking to 2.7 liters. The one that piqued my interest was their Z-head mod. It replaces the stock cylinder head with a JDM cylinder head with higher flowing/higher velocity intake tracts, larger valves and higher compression. It also uses the DJM intake manifold with equal length runners that are longer than the typical EJ253 US manifold. It has to be modified to accept a throttle cable instead of drive-by-wire. The normal intake isn't a restriction point, just that the Z-head boosts both torque and hp. As I recall this had has better cooling passages, too, which helps with head gasket longevity. The cam is left stock to preserve the shape of torque/hp curve. The stock injectors are replaced with blueprinted units held in place with billet fuel rails that hold the injectors more securely and maybe helps fuel flow, but mostly looks cool. An idle control circuit is added to aid cool weather start-up/idling. Ignition and fuel management is handled with a Stinger control unit using crank trigger and cam trigger. This allows complete custom mapping of ignition and fuel. The motor has been given a quick tune on the dyno and when the car is complete it will be tuned on the rolling road unit with its exhaust and intake in place. The exhaust specced is a Subie version of the A-1 sidewinder w/center exit. The intake is a simple silicone hose with an enormous filter on the end. John predicts 200+ crank hp and similar torque based on what he's accomplished with these builds before. That's the sweet spot for me in a sub 2000lb car. Properly broken in and maintained it should be good for 200,000 miles.
Other mods include a custom water crossover pipe with with reservoir, this becomes the highest point in the system for the radiator cap and for cooling system bleeding. It has the connection for the overflow tank as well. The coolant inlet and outlet have welded AN fittings for the water lines, the aluminum radiator also has welded AN fittings. Greg insists on using AN fittings for this and I'm on board 100%. Greg has had no cooling issues with this set-up; it is well proven in his Subaru builds. The oil pan is shortened, and in sand rails they have found that if you run the stock oil capacity the new baffling keeps the crank out of the oil and prevents starvation without reducing volume. This means a non-standard dip stick, too. Outfront typically gives the manifold, valve covers, and bolted on aluminum bits a light polish. It's not my favorite look, but it does look really nice with the chrome alternator, so the engine compartment will look pretty blingy and I didn't see the point in upsetting John's production process and slowing down the build. I may change that myself at some later date, but I'll at least put on some ceramic coating so it's easy to clean and to keep it from corroding. For sure I'll bring it to cars and coffee events or the occasional show and shine, but I'll probably arrive with the front all covered in bugs and the rear covered in dust. Spending Saturdays cleaning an engine compartment with dental floss is not my idea of fun, nor my intent. The intent is to DRIVE, BABY!!!
Next installment will be transaxle specs. Given recent discussions it will be fun to see how different a route Stan and I have taken, but how close we are in thinking and execution at times.
Peace and clean hands to all,
Michael