So, had a thought that wasn't painful

For the last week I have been driving a mazda3 skyactiv automatic.

Averaged 37mpg.

I typically drive a protege5 automatic that gets about 27.

The protege is a lot more comfortable, lighter, more aerodynamic, and far cheaper.

Why couldn't you stuff the 2.0 skyactiv and six speed Auto into an older protege? Has there been someone that has done something similar? In my head, this seems like a great idea, and rather inexpensive.

What says the hive?

The mazda3 is a newer car infact the sky active means its even newer, I wouldn't be surprised if the engine bolted up but it would be pretty hard to get all of the computer stuff to line up and getting the engine to talk to the gauges would be a bit of a challenge.

Do it. I'll grab the popcorn.

Biggest issue is the engine arrangement. The Skyactiv is flipped 180 degrees from the arrangement in the Protege.

Protege:

Mazda 3:

So you would have a lot of adapting to do and it's not going to be an easy adaptation.

In reply to bmw88rider:

Looks like just intake and exhaust, the belts are both on the passenger's side and the trans are both on the driver's.

Anything is possible, buy you would really need a donor vehicle and basically transplant all electronics from the newer car onto the old shell. ECM, BCM, fuse box, instrument cluster. All the emissions stuff and possibly fuel tank and HVAC system too if you wanted it 100% code less.

The electronic parts are the real concern, as well as the fuel system for the direct injection.

I'm guessing that I would be the first?

And, with the newer electronic stuff, do you need the factory gauges, or could you run a set of can bus speedhut gauges?

Sedan or Hatch 3?

The Sedan has a Cd of 0.26
The Protege5 is probably somewhere north of 0.32 (Mazdaspeed Protege)

That's a huge difference.

In reply to ProDarwin:

I was going to bring up aero too. The SkyActive engine in the Protege might gain some fuel economy, and the (presumably) lighter Protege chassis might help to offset some of the aero losses you'd run into compared to the newer 3, but getting upper 30s without some aero mods or driving style changes might be a reach.

It would probably be much easier, and far cheaper to spend some time with some coroplast and tape trying reduce the drag coefficient than it would be to struggle with the engine swap. But the swap would be cool.

There are other things too. They went to drive by wire on all of the mazda 3's and I believe all of the proteges are throttle cable. Most of the wiring is pretty self contained.

Honestly, The Skyactiv only got 2 MPG over the MZR motors in fuel economy. I would get 34-35 MPG in my 2.3L Mazda 3 in steady state highway cruising once I switched over to synthetics. It was a really cheap car to run down the highways.

Not much to add, except that fuel mileage is one of the main reasons I got rid of my P5 after only a year. If I'm going to drive around in an econobox, the damn thing ought to at least be able to break 30mpg.

bmw88rider wrote: There are other things too. They went to drive by wire on all of the mazda 3's and I believe all of the proteges are throttle cable. Most of the wiring is pretty self contained. Honestly, The Skyactiv only got 2 MPG over the MZR motors in fuel economy. I would get 34-35 MPG in my 2.3L Mazda 3 in steady state highway cruising once I switched over to synthetics. It was a really cheap car to run down the highways.

I was seeing that mpg and higher with my 2.3L 3. My Protege 5 was fun and tossable but it was tough to break 30 mpg

Hmm....

So, would that mzr be an easier swap? The fsde in these is an old design, and I think more speeds than 4 in the automatic would help.

And on aero: I'm planning on experimenting with chloroplast when it's not so damn hot.

This is more of a thought experiment at the moment, but also research for the next project after the challenge car. I'm thinking cheap blown up p5, later drivetrain.