Scirocco Miata chassis swap

That's right, I'm going to weld a Mk1 Scirocco on to the floorpan of a Miata. (Well, at least that's the plan.)

After years of working on the family cars I've decided to build something just for the fun of it.  I've owned a bunch of Miatas and I love driving them but I'm getting sick of having the same car for over 10 years.  I've always loved Mk1 Sciroccos but I no longer have the desire to own a front wheel drive car.  Actually I recently sold my '81 Rabbit.

So after finding a few build diaries of chassis swaps I've decided to do my own.  It's going to take quite a while since this is just for fun and I will only be able to work on it when I don't have anything else needing to be fixed.

Others' swaps that have inspired me to jump off the cliff:

MX-5 under a Datsun wagon:  http://build-threads.com/build-threads/datsun-411-mx5/

MX-5 under a VW type 3: https://jalopnik.com/this-1968-volkswagen-fastback-is-actually-a-miata-1825036646

MX-5/Mini clubman built in a space the size of my kitchen: http://retrorides.proboards.com/thread/144316/mx5-powered-mini-clubman-estate

Hopefully this will help me to keep making progress and people will find it entertaining.

I have pictures but I'm trying to figure out photo hosting.

Here is the Scirocco roller I recently bought.  It's mostly rust free except for the driver's outer rocker panel and the top of the driver's door.  It's mostly complete except for the hood that the PO dropped off his truck so I will need to find one eventually.  I have the original but it is very bent.

Sweet! Did you see this:

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/volvo-p1800eskinda/72311/page1/

In reply to RossD :

Not yet but it looks great!  I love old Volvos.  I saw the P1800 coupe on the build-threads site.  I'll look through it all later.  I'm planning on using everything from the Miata from the front sway bar back to the rear of the rear subframe and halfway up the firewall.  I want to use the Miata steering column but the Scirocco dash and steering wheel.  I will need to stretch the Miata about 6.5". 

I got a free Miata kinda-roller to practice on and start taking a bunch of measurements from.

This is after I stripped it and started cutting away some of the unneeded sheet metal.  It is way too rusty and bent underneath the floor to use on the Scirocco.  I will be able to use the driveshaft, PPF, and some of the floor to stretch the car the required 6.5".

Here is my old-school drawing to help with the planning.  I got some photos off the internet and with a doc cam and projector I drew them on a big piece of paper.  I got both enlarged to 50% of real size so I can actually measure off the drawing and just multiply by 2.

I would have done this in CAD but I don't have access to CAD at my current job.  You can see the two locations of the Miata vs VW seat, dash, steering wheel, and pedals.

Cool stuff, I'm looking forward to seeing how it progresses. Some day I'd love to do a chassis swap. For now I'm challenged enough just making a Mk1 Scirocco into a ...Mk1 Scirocco. If you can, post plenty of pics of how the Scirocco comes apart - I haven't dug too deeply into my chassis yet.

This topic of a Miata body swap has been on my mind of late. I am excited to see how this turns out. 

What are are the differences of the wheel base and track width between the two?

Definitely read through ALL of NOHOME's Molvo build thread. Also watch Project Binky on YouTube if you haven't seen it. Both cover well many of the gotcha's you will face.  Actually fitting the body to the pan is the easy part.

In reply to AAZCD :

This Scirocco is a strange mix of zero rust underneath and lots of questionable paintwork up top.  The more it look at the lumpiness of the body the less guilty I feel about cutting it up. I would love to help others by cheaply selling what I don't need.  What's your scirocco like?

I love the Mk1 Scirocco. It's one of the best looking cars ever designed in my mind. This is great.

In reply to Ian F :

Thanks for the heads up on the other builds. I'll definitely check them out.  I want to do as little engineering on this as possible.  That's why i want to swap the whole chassis as complete as I can.

In reply to Somebeach :

Thanks!  The Scirocco wheelbase is about 5.2" longer so i will need to lengthen the driveshaft and the powerplant frame. I'd rather not have to.  The front track is close.  The Miata is only 0.1" per side.  But the rear track is 1.15" wider per side on the mazda.  I'd also like to have room to run up to a 225mm tire. So that's a total of 1.94" more room needed in the rear.  That's way outside of the factory fenders.  

In reply to Keith Tanner :

Thanks Keith!  That means a lot coming from you.  I've read through all your Targa posts and I already bought a Rabbit fender repair panel after reading about your MGB GT project.  I'm going to need them to get an extra 2" of clearance per side in the back.

I love what you are doing.

Link to miata body swapping you tube stuff.

urchfab

Extending the driveshaft is cake -  any driveshaft shop can do that for you at a good price. You can do it yourself with some careful fabrication. The PPF is a little more difficult but you could potentially just bolt in an extension if you don’t want to weld. 

Rabbit flares should work well on the Scirocco for obvious reasons!

In reply to chinman :

Are you positive that the extra length needs to be added behind the seats and NOT in front of the firewall? 

Put the drivers seats in your position of choice in each car. Then measure from the front axle to the middle of the seat base. How close are they? You don't want to be driving from the back seat and you dont want to be up against the glass when the Miata front wheel is in the Scirocco front wheelwell.

If the goal is to not have to re-engineer the whole car, then put a lot of thought into how you are going to blend the two cars at the firewall.  The Mazda engineers spent a lot of time making this zone work and moving any one item sets off a domino effect where if you move one thing, the whole matrix changes. Aim to keep all of the  controls and HVAC system from the Miata.

Much like you, my original thought was to keep the more vintage dash. However, once I ran into the realities of doing that, I bailed and went with the dash that fits the firewall and the hardware that Mazda put there. 

Pete

In reply to NOHOME :

Thanks Pete. 

Cue the sound of a can of worms being opened...  I have put a lot of thought in to this part and it's tricky.  The two cars are very similar in dimensions except for the placement of the front wheels in relation to the driver.  The Miata, as you already know, has you sitting close to the floor with the wheels out in front of you.  The wheelwells are totally in front of the firewall.  In the Scirocco you are sitting a little higher which bring the petals closer and the wheels are very close to the fire wall.  About a 1/4 of the wheelwells are inside the cabin. 

I looked in to doing what you suggested and decoupling some of Mazda's placement of the components around the firewall but doing so gets ugly fast.  

The front wheels need to be centered in the wheelwells so that locks in the position of the subframe. This, in turn, locates lower frame rails (subframe lower mounting points) steering rack, engine, transmission, and shifter placement.  This then dictates firewall clearance behind the motor which locates the pedals.  If I were stretching things in this area maybe I could do it but I actually need to compress everything about 6 inches.  The best idea I could come up with was to lock in the subframe and then notch the subframe for oil pan clearance to allow me to move the motor, and the rack, forward about 4.5".  This would allow me to move the shifter, pedals, and steering forward but trying to relocate the lower mounting points further under the car doesn't look very easy.  I also am concerned about the potential bump steer issues from moving the rack so far forward in relation to the spindles.  

I also plan on dropping the body of the Scirocco about 1.5".  That will make the wheel clearance even worse.  Man that's a lot of typing!

Do you think I missed something?

In reply to NOHOME :

You added to your post while I was typing my dissertation.  

My "plan" is to use the top half of the scirocco firewall and the bottom half of the Miata firewall.  Because of VW's silly rain tray this gives me a lot of choices for connecting the two.

6" of difference is a lot but from my preliminary sitting and measuring I don't think it will be too bad.  Thanks for your input.  This is one of of the reasons I am doing the build diary.

I think I will space the VW dash out a little to account for the difference. This is ver easy to do on the VW.  Either way I won't fully weld anything until I am sure.

I would consider moving the wheel opening forward. That is pretty easy to do.

Have you actually measured how much further back from the front axle the Miata seat is than the VW? 

What is the plan to add to the Miata wheelbase?

Pete

wheelsmithy said:

I love what you are doing.

Link to miata body swapping you tube stuff.

urchfab

Wow. I am about 8 episodes in. And wow. 

Width wise, just use Group H, Berg Cup or Trans Am arches.. all available at reasonable cost in the US. One of the US suppliers even sells complete fibreglass quarter panels and front fenders..

Somebeach said:

wheelsmithy said:

I love what you are doing.

Link to miata body swapping you tube stuff.

urchfab

Wow. I am about 8 episodes in. And wow. 

Geez, this build is addictive. 20 episodes in so far. 

In reply to NOHOME :

I plan on lengthening the driveshaft and PPF.  I'll also use a section of the floor from the silver Miata I have already to add the 6 inches behind the seats.  I will have two driveshafts and two PPFs to work with.