Hi guys,

I don't own a Miata yet, however I do own a very rad set of widebody goodies for one... I'm here to learn about the swap. I'm no stranger to dropping in a more powerful engine in an unfortunately under-powered car. I just finished a motor swap on my 1986 BMW 325es; well the motor was one of the many things I swapped out of it (I refurbished the entire car and upgraded it). Frankly, I understand the effort, scope and cost of doing a swap properly so I'll probably just be drooling for the next few months.

My current vision is to build a fast, safe, street functional and really good looking Miata; ideally more show and enough go to be respectable. I know the V8 would be a good power plant, but I'm not canceling out a stroked/turbo/super charged/s2000(!?) motor...I'm not even sure I'm making sense to you at this point. Even though I've have experience with forced induction, I still know little to nothing about Miatas.

Side note: I have noticed that the motor swaps seem to increase the market value of the car significantly. This is not so much the case in the BMW world; there is an effect, but not nearly as significant.

See you around, Thanks for reading.

Pete

 

Hi PeteD, enjoy your stay :)

 

Welcome Pete!

If you want to go the kit route you are basically stuck with two main options: a late model GM LSx engine (Camaro, Firebird, GTO) or a late 80's-early 90's Ford 5.0 (Mustang, Explorer, Lincoln MkVII). With a little ingenuity each of these kits can be expanded outward to include some other options such as early carbed versions of the Ford 302 or iron-blocked truck versions of the LSx. The Ford kit has even been adapted to work with Rover V8's. Since the front and back of the car are only really connected with a custom driveshaft you can pick and choose the rear end of any of the kits to go with the front of any of them. The Ford kit (Monster Miata) uses a Ford Thunderbird IRS 7.5" center and the GM kits (Flyin' Miata, V8 Roasdsters) use a Ford 8.8 or GM rear.

Main kit differences:

-The Monster Miata kit includes more and is cheaper.
-The Flyin' Miata/V8 Roadsters kit includes a tube front subframe, the MM kit modifies the Miata's existing frame.
-Both kits can be made to use a T5 or T56 trans.
-The Flyin' Miata/V8 Roadsters kit requires removal of the car's interior and cutting/welding of the tub. The MM kit only requires some welding to the rear subframe.
-The LSx kits give you more "out of the box" performance but the Ford 5.0 (IMHO) just looks less "busy" in the Miata engine bay.

There are other differences that I'm sure will be posted up. I prefer the Ford kit/engine but I think that's primarily because my father taught me at a very early age to worship the blue oval. I've built 4 - 6 Ford 5.0 conversions depending on how you define a "build". Many others here have built the LSx cars. Cardomain pages for my 4 main builds can be found in my signature.

Again, welcome to the madness!

-Jason McCully

 

Sorry, I guess some links would help:

V8Roadsters (LSx kits):

V8 Roadsters

Monster Miata (Ford 5.0 kits)

Home -

My site which offers some parts to help out with the Ford builds as well as links to my builds:

McCully Racing Motors- There's no Replacement for Displacement.

-Jason

 

Thanks Guys! Jason, I appreciate the links.

 

Welcome Pete. I'm new here as we'll, but not new to Miatas. Your E30 looks amazing. If you have time, please share more info and pics or a link. I'm such a fan of these particular BMW's.

It's pretty neat that we have several good kit and engine choices for our cars. I'm going with a V8R kit myself. But the 5.0's are awesome too! Jason's cars appear to be so well done as well.

 

Hey! I'm happy to share some info on it. I haven't made a build thread yet. However, in summary - the motor is a 3.0 bottom end, m50 (non vanos) top end with 325is non vanos intake cams (I think the most aggressive BMW made cams for that head). The motor is basically an s50 motor without the vanos. Attached to the motor is an 8.5 UUC flywheel with a 5 speed e36 transmission. I painted it imola, which is the e46 m3 red. I rebuild an older (NLA I think) body kit for it. Swapped the suspension over to five lug (mainly for the rims I fell in love with) and actual suspension itself is fairly stiff (H&R Race Billy Sports). There are a lot of little parts that go into the swap, but that is the main idea.

The picture with my grandmother is what the car looked like after I first "freshened" it up. The KMC one is how it looks today. I can get some more recent pictures if you are interested.

Here is a video of a dyno pull with 17lb injectors. It has some room for more power with bigger injectors.

 

LS E30 once you get the LS Miata done?

 

haha, that'd be nice. It's crazy how minuscule the weight difference is in the engines and the feel of how the weight is distributed (long six vs. shorter/wider v8). What is different about the BMW motor swapping community, is the value of the car typically decreases when a non BMW motor is swapped into the car. That's not a reason to not do it, but in the Miata world, sale prices seem to at least fetch a break even point, or close to it.

 

+1 for LS BMW!!