Engine position, Questions related to Subaru Swap Options

[Lilchopshop]

Hi All,
I’m sure this has been discussed in other posts here, but I’m not having luck finding them…. I’m building a Suby-swapped 914. I’m using the 2.2L motor and 5MT from a ‘99 Legacy. I want to build my own engine cradle and I might make my own engine mounts that are tied into the rear suspension ears similar to what @tygaboy is doing on his Ferrari swap. I don’t mind cutting into the trunk for clearance, but I still want a functional trunk and storage for the targa top.

I’m at the point now of trying to find the optimum position for the engine/tranny and I have the following questions:
1. Crankshaft angle; I’ve seen others try to keep the angle parallel to the ground. If I do this, the engine will be very low unless I make big cuts into the trunk floor for the transmission. What should I be looking for relative to engine height and crankshaft angle?
2. CV angle; I know that less angle is better, but the output shafts on the Suby transmission are very far forward. If I align these to the trailing arms, the whole engine/transmission ends up very far back leaving no room for a muffler, making intake plumbing tricky and shifting the CG of the car rearwards. I’m planning to get custom axles that will use the Subaru inner cv joints and the 914 cv joints at the wheels. With the mock-up I am doing now, i have things in a position where there is just enough room to fit a muffler behind the tranny and gives me enough room between the stock intake manifold and the rear of the engine bay. However, this position has the cv axles sweeping backwards at about 15.5 degrees when the trailing arms are horizontal. Does this seem like too much?

Anything else I should be considering here?

[Superhawk996]

1) Engine should be a low as possible while allowing for reasonable ground clearance to the lowest point on the engine. Unless running a dry sump engine, it is likely that your oil pan will limit how low the engine can go. Wet sump engines are at a serious disadvantage here. Keeping the engine low, lowers the vehicle Cg and aids handling. Whether or not crank should be parallel to the ground is more dependent on oil pickup and how your oil pan is designed.

2) Positioning the engine to package the muffler as a priority is a very bad plan. Let the driveline angles dictate where the engine goes. Don’t forget about driveline angles in full jounce and rebound.

I can tell you when OEMs package the muffler - they are fit into what ever space remains after the suspension and driveline are packaged. This is why so many modern cars now have odd shaped mufflers that are essentially shrink wrapped up behind the rear fascia in the leftover spacial voids.

Better to have to custom fabricate exhaust and mufflers than have a driveline that tears itself to shreds because CV joint angles weren’t respected.

[Lilchopshop]

1) Engine should be a low as possible while allowing for reasonable ground clearance to the lowest point on the engine. Unless running a dry sump engine, it is likely that your oil pan will limit how low the engine can go. Wet sump engines are at a serious disadvantage here. Keeping the engine low, lowers the vehicle Cg and aids handling. Whether or not crank should be parallel to the ground is more dependent on oil pickup and how your oil pan is designed.

2) Positioning the engine to package the muffler as a priority is a very bad plan. Let the driveline angles dictate where the engine goes. Don’t forget about driveline angles in full jounce and rebound.

I can tell you when OEMs package the muffler - they are fit into what ever space remains after the suspension and driveline are packaged. This is why so many modern cars now have odd shaped mufflers that are essentially shrink wrapped up behind the rear fascia in the leftover spacial voids.

Better to have to custom fabricate exhaust and mufflers than have a driveline that tears itself to shreds because CV joint angles weren’t respected.

@Superhawk996 , Good advice here, thanks. There are a few good reasons for pushing the engine forward, other than muffler clearance, but I'm now starting to consider dual mufflers on either side of the trans rather than one behind.

The inner CV joints I am using have a 22 deg maximum. I'll never reach this point, but I'm thinking it will be much better if I'm not running at 15-16 deg all the time. Moving the engine rearward just half an inch reduces my CV angle by almost 5 degrees.

With respect to engine height, the stock subaru oil pan definitely causes some limitations. I am probably going to shorten the stock pan or buy one of the cast aluminum pans from Smallcar performance.

I was hoping to hear from some of the Suby guys here, but I think I'm starting to narrow in on the optimum position now.