To restate - very cool project Jay!
Be sure to take into account your chassis length into all the "fitting and measurements".  Pretty sure Paul's Imp runs a slightly longer chassis than the std. 80" Manx.  Not sure where the difference is, but guessing it's more or less behind the front seats?  Sounds like you're planning the under-the-rear bodywork radiator location, so be sure the package doesn't come out too long to fit under there!

I can take any measurements you'd like off my engine, which is sitting on a dolly for the near future.
From your description I gather you're fitting the turbo version motor?  Running a standard Outfront exhaust?  Fitting an intercooler will be the biggest challenge from what I can see.  You might consider a straight J tube for the initial install, just not sure how that works with the OEM ECU?  Be sure to fit a boost gauge in your instrument plans!
Jeff

Jeff, That's all good info.
I would like to fit the radiator under the rear deck. As it comes down a ways in the rear, I would think this is a possibility. I spoke with Paul about rad size, and he has seen the size successfully come down in size (from when these conversions first started making their way into buggies) and I'm hopeful to be able to hide some kind of rad under the rear there.

As far as the engine goes, Paul MAY be getting it this coming weekend. Once he physically has the engine in front of him, we'll be able to tell more what will happen with the build. Its unclear just exactly what the engine comes with. Intercooler? Intake? Plumbing? etc etc.

What I really wish I had was a rear before (with a VW engine installed) and a rear after (subi engine) picture to be able to compare.

I could overlay images to visually see where the subi engine is in relation to the crank pulley and alt/gen pulley. From there, I would be able to overlay the subi engine on my rear photo and scale off some measurements so I would know how ifs all going to fit together ahead of time.

I will need to go shopping for Tach, water Temp, and as you say, Boost pressure. I'm going to have a look and see what I can find for matching gauges.

Jay

Hi Jay - Jeff has some good points there.  My Imp is shortened 12" instead of the standard Manx 14.25".  The difference is behind the rear seats but I will keep that in mind and will have Pinkaru (14.25" shortening) just across town to take measurements from.

I like the picture overlay idea. I'm not sure I have any pictures "straight on" to the tail of a subaru install.  I have 2 Imps, one with and one without a Subaru. Both have matching lift kits.  I could see if I could get identical pictures of both over the weekend.  That would be a start. 

I also had an idea to make a "plug", maybe by surrounding the engine with the adapter and shrink wrapping it.  Then I would carefully cut the shrink wrap off and send it to you so you could see how it would fit under the body. 

Can you take a measurement from the back of the transmission horizontally to the bottom edge of the tail? I can then compare that to my installed EJ20 and the EJ22 on the engine stand to see how it compares.

The plan will be to use the stock Subaru exhaust and turbo placement, but the OutFront exhaust may be an option as well.  OutFront designs for sand rails, so they don't take into account the position of the tub buggy back seat.  On my EJ20, the whole intake is flipped 180 degrees which makes mounting the alternator a challenge as it doesn't fit under the flipped intake. On Pinkaru, the throttle body has almost a 180 degree bend between it and the intake for clearance with the back seat.  OutFront's exhaust would make mounting the radiator behind the buggy interesting.

Tach, water temp and boost pressure are all great gauges to have.  The intake should have a spot we can run the boost gauge from. 

Paul...

That's a great idea about the shrink wrap plug. I was thinking about cutting a cardboard template so you could see the room available to work with.

If you made a plug, It wouldn't be difficult to make a (+) dummy shape. Have you ever seen the shipping material that looks like expandable foam inside of a garbage bag? I imagine a shape could be made like this. It would be light weight and although not detailed, would provide a way to figure out if you were going to have any interference issues.

The picture overlay idea should function well enough with two identical bodies (like you said with identical lifts).
If you can get similar pictures, that would be great. If you have a tripod, where you could fix the height, then measure back, I imagine that will be close enough to work with. If you let me know the measurements (from the ground to the center of the lens and distance back from the rear axle, I'll be able to duplicate the same image and the overlay shouldn't take a lot of playing to get right.

"Can you take a measurement from the back of the transmission horizontally to the bottom edge of the tail? I can then compare that to my installed EJ20 and the EJ22 on the engine stand to see how it compares." The only issue with this is that the trailing edge is not vertical. It lays back at an angle. I think having this measurement along with a cardboard template will be helpful to you.

I'd like to hide the rad up under the fiberglass tail if I can get away with it. There are two stiffeners that are in place when the body was made. I may need to cut these out of the way and glass in a stiffener once the engine is in place. I'm not worried about cutting the stiffener though... just the gel coat area of the body.

I saw an image the other day of a subi intake with a "J" tube. From images on the manx site, I know this protrudes into the rear seat, which is not desirable. I would rather flip the intake 180 and relocate the alt. Actually, from a high vantage point of a Subi engine, I don't know why an offset manifold isn't made that could incorporate the alt to the side of the intake tube. I wish I had an intake here to play with. It looks like the alt could easily shift off center to the left of the engine and the intake tube could stay to the right of the alt, then dive back to the manifold. Obviously the manifold would need to be redesigned to accept the angle of approach from the intake tube, but it could be done. Sorry... thinking out loud.

OK, I've got a lot of work to do.

Jay

OK, here's my thought for hiding the radiator ultimately:

From the rear:

Side View:

Interesting!  As you know, my crazy mounting above my transaxle is often questioned, but I have not had an overheating problem.  The Imp doesn't have a spare tire or battery box (well - this one doesn't) to worry about.  Your buggy body has both those in the way for an over the transaxle design.

Some points we will have to figure out:
How can the radiator be supported way up there? 
Will the fan(s) mount below and push the air up into the radiator?  Might as well use the natural flow of hot air to our advantage.  But I wonder what direction the normal flow of air is back there.
So this would push air out the sides while drawing it in from below.  It may be against the normal flow with air coming from under the fenders.  May have to experiment with this.
Tubing up to the ports should not be bad.
How do we fill it?  If we had a vacuum system, we could suck all the air out and let the vacuum draw the fluid in, but without that, it will have to have a vent at the very top of the radiator to ummm - fill AND vent from?
I'm not sure how a catch can or over flow can would work for this?  Taking the cap off might cause the radiator to empty. 

Those are my thoughts.  Should be interesting. Paul...

filling would be a B!^*#... I'll give it that. If this location even has enough space... Yet to be determined once I can figure out  exactly how many BTUs need to be dispersed... I could easily cut a small access in the glass behind the rear seat upright. The seat could be unbolted, and the rad and cap could be filled with a funnel. Since the rad cap would be the high point, as it is in a car, the cap would automatically vent and fill through the catch bottle with normal expansion and contraction.

As far as the flow of air, I'm not sure how I would be able to find out, aside from someone videotaping strings of yarn flying around back there while I'm driving. (Oh MY GOD... I'll add that to my list of things to do, LOL) Seriously though... A pusher fan or a puller fan, it doesn't matter to me. I don't care if a pusher is mounted under or a puller is mounted above, but my thought is to stay with the same natural convection flow while idle, which would be air rising, pulling in cooler air from the bottom of the rad.

I'm going to have to give you some serious dimensions. (I drove home last night and forgot to measure the tail overhang from the bell housing, ARGH. I'm headed back home tonight too, so I'll try and get you some serious measurements by the end of the weekend.

Jay