Introducing Colin - a Mini-ature WRX

Weekend 13, day 1 (March... what day is it?  AAAAAAAAAUGH)

So.  After a lot of screwing around removing things from the WRX tunnel, then slicing the Mini tunnel top off...

We get to here. Mini kick up needed some sledgehammer massage for driveshaft clearance after all.

Now comes the math.  The drivetrain is at a 7.65° angle. The differential is at a 1.65° angle.  This means there is 6° of angle to be taken up by the driveshafts.  If this were a straight driveshaft, each U joint would need to be at a 3° angle, which is both kind of a lot, and also assumes that the diff is the correct distance lower from the drivetrain. This is rarely the case!

So really, because there is a center CV joint to take up slack, I need to take the midpoint of the drivetrain angles (half of 6 = 3, plus 1.65 is 4.65, and likewise from 7.65) and make sure the two driveshaft angles bracket that figure. While trying to keep U joint angles under two degrees. And allowing room for a 3" exhaust between the carrier bearing and the exhaust hanger plate. Bearing in mind that the two halves of the driveshaft are of different lengths, as well as the components not at complementary heights to each other.

Meat is on the grill, Red Bull is in the hand, time to think.

Ok, think I got it.  7 degrees on front shaft, .3 degrees on rear, which is pretty durn close. Down is as good as up as long as it is even. 

I am going to change mind a few times. Raising the bearing will increase front angle while decreasing rear... may do that.

Also.

Shifter cable fits. Guess I didn't overshorten the driveshaft after all.

Heh. Glad I slept on it.

Didn't fully trust the way I measured the diff angle, did what I should have done yesterday and removed the driveshaft, cleaned the rust from the flange, and measured directly.

0 degrees even.

Well, okay then. That changes a lot of things.

And the shrieking monkey frustration starts.  Got everything trimmed, cleaned up, blocked up, verified clearance to important things, tap-screwed in place, measure angles one last time before things are Permanent...

1.5° rear, 7.5° front.  Que?  Measure engine... 6.7°.  Que??

Are you using harbor freight measuring devices?

Nope, Matco brand.  Very frustrating as I used a handy table to verify that it reads appropriately on all faces in both directions.  It is almost like the driveshafts are tapered... which is probably something I should have checked.

I walked away from it, assisted by Evan needing the welder's extension cable to run a jackhammer.  And a really grody medical condition that turned up this morning that made constant crawling under the car and back a real pain, and I was just done.  

The shifter mechanism is REALLY close to the driveshaft, too.  I am thinkin', comma, that I will egg out the holes in the trans mount to shift the trans a little to the left.  This will also straighten out the driveshaft a bit, I think.  Easy to get crossed up looking at it from underneath.

Of course, moving the trans over will require that more of the Mini floor be cut out.  Right now there is just the outside edge of the box section that defined the bottom of the old tunnel. There is no real reason to keep it, I suppose, and the pedals have to be moved over a lot to the left anyway..

.....yeah.  You can see the front U joint in the shifter hole.

Measure once, walk the drill bit, egg out the two bad holes to match the one that went where you wanted...

Much better!

The welding of German Scheißmetall and Japanese kusogane is complete.  Lots of zip screws to pull the two together, tapping with a sharp edged hammer to shrink the Mini tunnel to meet the WRX tunnel, working five or six inches at a time.

I tell myself that all the times it burned through the thin Subaru metal was so I could get weld bead to the inner layer, as the Impreza floor is actually two thin stampings clamshelled together.

The seam on the underside will be addressed later, after the drivetrain is back out and the stands are placed all the way up so I am not welding six inches from my face.

So I remember what settings actually worked.

I used up all of my welding skill yesterday.  Discovered what Adam was talking about when he said he hated caging Minis: Undercoating kept blowing up at me.  But this is done.

Much tentative cutting got me to here:

17x65x15 tires fit, barely.

Thinking time.

I can believe how well you are getting all of this to fit!

In reply to java230 :

The interesting thing is that, looking at the numbers, an R50/53 and a GD are almost the same size, except for the overhang.

The Subaru is an old design paradigm, as they mostly just added more folds and creases to the GC, which was a shorter Legacy, which was a control arms and rear struts conversion of the GL, which is where my Subaru history knowledge ends but I am sure the base dimensions go back even further to the torsion bars and pushrod engines era.  The Mini is a much more modern car with the wheelbase pushed out to the corners as far as possible, with the interior sitting inside the wheelwells width wise as well.  The Mini has a lot lower floor than a Subaru, and the firewall is more forward (oddly enough), which is where all the channeling comes in.

Still thinking about internal air cooling for the engine.

Weekend I don't want to think about it, day 1: (April 2)

Cleaned up a lot so I can start working on the exhaust.

Got as far as here:

...then got called back home for a minor emergency.  Le sigh.

Yes there will be a flex pipe.

It won't exit at that angle, though.

Not sure how I will support the tail of the downpipe to the transmission.  I really don't want the weight of the exhaust hanging off of minimal hangers.

Weekend 15, day 2 (April 3):

Morning got sidetracked a bit by a GRMer and Fiat in need, but managed to get down to the COG by three for a few hours of exhausting work.

Heh.  Exhausting.

To work on the exhaust, first we must fix the driveshaft bearing support.  When I mooshed the tunnel to fit the Mini, it got narrower and also moved the two bolt locations together.  I had ground the sides of the carrier flush with the bushings, at which point I discovered that you can't do that or the bushing outer sleeve can fall out.  My thought was to eliminate the sleeves and weld washers to the bearing instead, raising the bearing and giving some critical exhaust clearance.

That lasted as long as finding out that without the bushings, the bolts would bottom out against the upper shell of the tunnel.

Moving right along, I decided to try to just egg out the inner sleeve of the bushings.  The first one spun the bushings assembly right on out.  Oops.

Not willing to let an accident go to waste, I just egged out the bracket so the bushing assembly would sit closer to the center.  Fortunately I'd started with the passenger side bushing, so this process would move the bearing to the right, allowing more exhaust clearance.

Bolt the mess up...

Weld in place, only setting fire to the bushing "a lot"...

And now we can actually start on the exhaust.  Well, after giving some sledgehammer attention to the bottom left corner of the tunnel/kickup interface.

You won't believe this, because I sure don't, the midpipe bends are kind of almost perfect, and the resonator works well right under the fuel tank.  First, we deflange everything.

Then after a lot of screwing around, using a scissor jack as a low profile exhaust stand, moving this, rotating that, installing the left side axle to make sure the pipe isn't pointed at it, so on and so forth...

Boom. Exhaust.

Still need to figure out how to hang it (I have ideas) and make the curlicue to point the tailpipe around the diff and out the center, but it came along nicely.  It even technically fits over the Mini center brace/exhaust bracket, but to ensure NVH isn't too horrible, the pipe will get mooshed and the brace will get spaced down a bit.

Since you're working on it right now, how important is a flex pipe for reducing NVH?  Trying to decide if adding one would help the in cab volume in my truck.

bigeyedfish said:

Since you're working on it right now, how important is a flex pipe for reducing NVH?  Trying to decide if adding one would help the in cab volume in my truck.

IME, it helps a lot.  I have actually used two in cases that I thought called for it.  Not only that, but they help extend hanger life and make exhaust fabrication more forgiving.  

This is all looking good.  My Quattro Audi Fox project took more than a year of spare time to get to this point, so you're doing great on my glacial time scale.  

Let me know what you need with the intercooler.  

this is gonna be awesome, following...  Part of me wants to see this with a big side exit hole behind the passenger door, but I understand that's not worth the effort, haha. 

In reply to golfduke :

It is even more of an issue than just looking tacky.  The sills are the structure of the vehicle, it would be a really bad idea to cut into them.

GasTungstenArc said:

This is all looking good.  My Quattro Audi Fox project took more than a year of spare time to get to this point, so you're doing great on my glacial time scale.  

We are specifically not doing any bodywork for this reason.

Pete. (l33t FS) said:

GasTungstenArc said:

This is all looking good.  My Quattro Audi Fox project took more than a year of spare time to get to this point, so you're doing great on my glacial time scale.  

We are specifically not doing any bodywork for this reason.

A wise decision.  It was also wise not to cut 9" out of the wheelbase, requiring body work to make it look right.  The shortening, plus the wide wheel arches to cover 8" wheels when 6" wheels could have *just* squeaked by, might, in retrospect, have been mistakes.  No external paint and body work would have been necessary if I had accepted those limits--and that would have shrunk up the scope, time scale, and budget to manageable levels.  Ah, decisions...  Yours is a good one.  This car needs to be up and running soon.  There is no time for goofiness and vanity.  

In reply to GasTungstenArc :

Goofiness and vanity is the whole reason for the project!   Well, more goofiness than vanity, but the visual/auditory disconnect is a prime goal.

Thanks to GRM Rock Auto discount code, just saved $25 on the necessary parts for the struts and the headgasket delete.

In reply to GasTungstenArc :

Not to threadjack, but I'm pretty sure I sold you the car that donated the engine to your Fox Quattro. Unless there's another shortened, widened, Audi Fox Quattro out there.

Turbine said:

In reply to GasTungstenArc :

Not to threadjack, but I'm pretty sure I sold you the car that donated the engine to your Fox Quattro. Unless there's another shortened, widened, Audi Fox Quattro out there.

There are so many that I have lost count.  But to be serious, the car is doing well.  I sold it to another enthusiast, who is nearing completion on the project.  He is currently engaged in a push to have it ready for Carlisle.  He's not sure if he's going to make it, but he's trying.