1.0L Geo Metro engine swap into 1990 Mazda Miata!

[California98Civic]

Here's an eg of such a modded Mazda, I think (moving quickly... gotta get back to work):

[Ladogaboy]

Originally Posted by FXSTi

It is not emissions which keep these out of the States, it's safety. They don't meet crash test standards. We really need to get safety regulations to add an exemption for Kei class cars, or allow lower standards.With airbags and other safety based designs, they are still safer than early Metro's or Festiva's.

Kirk

I'm still surprised Smart cars pass our crash test standards.

[MetroMPG]

Originally Posted by California98Civic

Here's an eg of such a modded Mazda

Yup - that's the fastback hardtop I'd seen before. I'd say pretty high odds it's good for measurable drag reduction vs. the OEM hard or soft top.

[fujioko]

Originally Posted by MetroMPG

Great - added a few pics and links to your YouTube vids in post #1.

What an impressive build - congratulations.

As for the goal of better highway economy, have you compared the Miata's CdA (drag coefficient x projected frontal area) with the Metro's? Aero losses outweigh everything else above ~25-30 mph.

FYI, the default values in the aero/rolling resistance calculator here are for a Metro of the same specs as your engine donor: Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

I saw you mention the hard top option as a potential aero gain. If you're talking about the tapered aftermarket "fastback" hard top I've seen in pics of some racing Miatas, it will likely help. The OEM hard top, probably not so much.

Thanks for all the interest! I see I have a lot of questions. Hopefully I can answer most. If I miss something ...ask again.

Hardtop and aero mods...

According to the Miata folks... there is a MPG increase when the factory hardtop is installed. I seem to recall the increase is about one - two MPG. A used hardtop generally cost $500-$800. An aftermarket fastback looks great but is very costly. I can justify the expense of a factory hardtop because I have a 2nd Miata that I want to get a hardtop for.

The Miata sort of looks aerodynamic but is not an optimized shape for speeds greater than 40 MPH. Drop the top and it gets worse.

Probably not a good car to start with but I like Miatas ...so I centered my project on this chassis.

I realize my choice of body-style and drivtrain configuration will limit the results and 60 MPG @ 65 MPH is probably impossible.

Originally Posted by MetroMPG

It makes a noticeable difference in low-end torque. I added an XFi camshaft (OEM fuel economy cam similar to 3tech's economy version) to my car. Though I didn't try to measure the change in fuel consumption (too difficult to get an accurate A-B-A comparison). http://ecomodder.com/forum/showthrea...leted-102.html

In combination with switching to the tallest possible final drive (for reduced highway cruising RPM) they made for a good combination. http://ecomodder.com/forum/showthrea...-gain-107.html


But my driving environment is very different from yours: I never take the freeway. Always secondary roads, so I'm rarely above 55 mph.

FXi camshaft

I'm really interested in a FXi camshaft experiment. The car currently has a 3tech 6* cam sprocket and the car seems to run better at highway speeds.

You probably read about the 3tech cam sprocket experiment I did. The results were more or less inconclusive because of the winter fuel reformulation. I eventually decided the 6* cam sprocket was better than stock but I'm going to do the experiment over when the summer blend is back on the market.

Another reason I'm unsure about the whole 6* cam sprocket is I discovered my GPS is flaky. The GPS crashes and the touch screen is always detecting phantom touches.

I did manage to get a few good numbers from the experiment that leads me to believed the sprocket may be a benefit.

I had an additional mishap and lost the sensor for the vehicle speed. Something really bad happened underneath the car and I haven't had a chance to look.

So... back to the FXi cam......

You indicate I may see some improvement with an XFi cam and taller tires or a lower gear ratio. Sort of use the torque and not HP to move the car. I can see your reasoning.

Lowering the car....

I'm sort of in a tough spot with this car right now. This Miata was perfect for the original experiment but it is almost imposable to alter. Rust is the issue that I have to deal with ... and everything on this car is rusted solid.

I want to lower the car 1-2 inches but I fear bad things will happen once I start to disassemble the suspension. This is an issue I'm debating and the only real answer is to get another Miata to drop the three cylinder engine into.


Emissions.........

I worked many years in an emissions laboratory and I'm familiar with the rules manufactures need to adhere to. NOX, HC, CO... and the balancing act to get it all to work.

I'm just not a rule follower.

Perhaps someday I'll sort it out.


Money....

nobody asked, but I'm cheap. Playing with cars is a hobby. Realistically I can spend lots of $$ and get outstanding results. .... but I'm in it for the adventure and challenge.

The other car....

I'm very happy with the G10 Miata but I decided to do a second build with a slightly bigger engine. This second build has put the G10 sort of on the back burner. What I'm saying is I'm delaying transplanting the three cylinder engine into a nicer car.

I continue to drive the G10 and experiment with it but unfortunately it will remain a rusty car for a little while longer. I really need to get a show on Discovery Channel or something.... seems like everyone else has one.

Anyway the other Miata I'm building has a 1.3 Ford Festiva engine. the link is Project B3 STEALTH. A 63HP Festiva powered Miata - MX-5 Miata Forum

I did a lot of research and prep work to make the B3 project something that can be duplicated.

Jim

[MetroMPG]

Love the Festiva/B3 engine swap too. It deserves its own thread here.

[fujioko]

Originally Posted by MetroMPG

Love the Festiva/B3 engine swap too. It deserves its own thread here.

Hi Darin,

I agree, this would be a great forum to post the B3 project in. I could certainly use the advice of anybody interested.

Give me about a week and I'll start the new thread.

Jim

[MetroMPG]

Most excellent.

[wwarren]

Fortunately there are a lot of new tires available that have been designed for low rolling resistance.

The Potenza RE92's are only LRR in the 165/65/14 size. That's a pretty limited option and would require considerably taller final gears to make up for the reduced diameter and you would definitely want to add skirts to the wheel openings to close the gap as much as possible.

I use 205/70/15 LRR Goodyear Assurance Fuel Max on my diesel Maxima and there are several other LRR brands in that size.

It would probably improve my Cd by going down to the 165/65/14... I have a spare set of 14x5.5 wheels for the Maxima but they may be too wide for a 165... hmmm...

Originally Posted by MetroMPG

I can vouch for the rolling resistance performance of Bridgestone Potenza RE92 14 inch tires designed for the gen 1. Honda Insight

[gsasquatch]

Wouldn't the Suzuki engine be a better fit in the Triumph, who's original hp and weight is closer to the Metro? My Spitfire seems to get poor mileage for being a 2000# 50hp car. (<30mpg), I would think the Suzuki engine would enhance reliability and livability with the obdII and fuel injection. Looks like the G10 has 2 more hp than the American version of the Spitfire, and you'd probably lose some weight going from Fe to Al.
I've got a rust free overdrive Spitfire for you if you want to give it a go.

[fujioko]

Originally Posted by gsasquatch

Wouldn't the Suzuki engine be a better fit in the Triumph, who's original hp and weight is closer to the Metro? My Spitfire seems to get poor mileage for being a 2000# 50hp car. (<30mpg), I would think the Suzuki engine would enhance reliability and livability with the obdII and fuel injection. Looks like the G10 has 2 more hp than the American version of the Spitfire, and you'd probably lose some weight going from Fe to Al.
I've got a rust free overdrive Spitfire for you if you want to give it a go.

Hi 'ya,

Before I decided to put the G10 in the Miata I had looked into putting it in my 79 Spitfire. The engine is short enough and certainly a lot lighter than the cast iron Spitfire engine.

My spitfire has always been garaged and is completely rust free. The frame rails and floor pans still have near perfect paint. I just couldn't bring myself to altering the car.

For some reason Spitfires don't appreciate in value like other British cars. Perhaps the G10 would increase the value??. Still thinking about this...