Metro-powered sports car project

[Arragonis]

Wouldn't know, never driven round London. Have sat in a GT6 round Oulton Park in the past though. That was lairy ;-)

[JackMcCornack]

I'm making some progress on construction. First things first--figure out how to place the powerplant. The mounting system needs to be robust 'cause if the car stops suddenly (like into a bridge abutment or an oncoming Escalade) I don't want the engine joining me in the cockpit. Ditto getting rear ended. So I'm putting the powerplant in a cradle made of 2" square mild steel tubing that wraps around the engine and will butt up against another 2" square tube at the back of the cockpit.

Step one was to make a powerplant simulator out of scrap metal. I bolted sleeves and plates to the engine mount and suspension attachment points on a Metro chassis, welded them together with bits of tubing, and ta dah! A thingie I could remove and measure without breaking my back or getting all greasy.

[JackMcCornack]

Next step (after the measuring and thinking and calculating etc, which doesn't count) was to make up the engine mounts.

I love CNC for small run manufacturing, and prototyping too--I have a deal with my local laser guys where I bring them G-code files to their specs, and they can run off prototype parts without having to do any setup or translations, which keeps it cheap. So nowadays I do all my sheet metal parts on the laptop, do a desktop test print on card stock, cut out the parts, form them over the edge of a table, weld them together with hot glue and Scotch tape, and if the paper parts fit I have a metal set made and build a prototype from them.

I generally plan on making one test-fit assembly that isn't quite right, but is close enough that the second shot will get it. It saves a bunch of calculating time if I assume I'll make a mistake or two, plus I'm such a crapola welder that I don't weld finished products...which means if I think it might work like a charm the first time, I have to bring in a professional to weld it. This way's faster.

Here's a cool technique for laser parts: to reduce fixturing and fitting sub-assemblies, I rely on origami. For a nice bend line that'll be exactly the same from part to part, I cut a line where I want the bend, leave it connected at the ends with tabs about as wide as the thickness of the metal, and then one can bend the part by hand and weld the cut back together after the part is installed.

Here's the left pickup plate (the part the left engine mount--trans mount, actually--attaches to), it has legs that fit (and weld) under the cradle tube and a center brace about mid-plate. The photo shows the cuts in the brace and how it folds, plus there are pix of the right pickup brackets (where the right motor mount attaches) already folded, plus how they fit on the 2" tube.

[JackMcCornack]

So, the right attachment points were welded to the tube to a measured position, the 2" tube cradle (a C shape at present--two sides and a back--with a scrap of 1" temporarily in the front to hold it solid 'til it's welded to the cockpit) made square and true (using a Craftsman digital level, a carpenter's square, and carpenter's clamps), the "engine simulator" placed in the cradle and the left and rear pickup points welded to the cradle. With the simulator removed, the cradle was dropped on a Metro engine/trans/mount assembly and woohoo! It fit.

[MetroMPG]

Hi Jack -

I just came across another project out there using some Metro (Swift, actually) parts as the motivating bits for a light DIY sports car project. Made me think of yours.

His is a somewhat different approach: the main one being he's going with electric propulsion. He's also modifying an existing Ford race car chassis to take the Suzuki transaxle, axles & hubs (RWD configuration).



Below is the Suzuki transaxle mounted in the chassis:



And he'll top if off by sticking a Lotus(esque) fiberglass body on top:



Project web site: szott.com

Probably won't be as low drag as your project, but I thought it was worth posting as brain fodder since people here seem to get a kick out of the idea of transplanting small displacement drivetrains into custom bodies.

Darin

[amcpacer]

I would love to see a Countach style super car look with a 1.0 engine. I suppose they were probably not very aerodynamic in their beauty!

[hypermiler01]

Imagine a Peugeot P81 without the wing.

[jamesqf]

Originally Posted by hypermiler01

Imagine a Peugeot P81 without the wing.

Nice, but I think I would keep the wing, modified as sort of the inverse of the bars on semi-trailers that keep cars from going under the trailer in a rear-end collision. There are too many jacked-up pickups & SUVs, driven by cell phone users, and I could just see myself waiting at a light while oblivious idiot rolls through on the red.

[Frank Lee]

Countach had bad Cd and the wing was notorious for knocking quite a bit of top end speed off.

[jamesqf]

Originally Posted by Frank Lee

...the wing was notorious for knocking quite a bit of top end speed off.

Better that than oblivious idiot knocking off quite a bit of MY top end :-)