Hey guys,

So this is my first post and I'm looking for some advice. Have a really tempting '91 Miata lined up, only downside is: it's sitting at 190,000 on the clock...

So here's the question, do I just leave it alone and look for something else? Or go with it and have some fun. I'd be swapping the engine and most likely the tranny too and then look to do some FI not too long down the road. But is the 190k too much for the frame? If I'm going with a different engine/tranny, and upgrading the suspension with the number on the body really matter that much? Just looking for any advice, thanks in advance guys.

And any ideas for the best swap for both the engine and tranny? What seems to be the favorite one around here?
Or just get a low mileage 1.8L and turbo it? (after doing everything else)

Added note: Since it's a '91 with 190,000 miles I'm getting it for a really good price, so I'll have plenty of room in the "budget" to build it up. Just want to make sure the frame/chassis would be alright to work with.

 

build a 1.8L, then drop it in and boost it. you'll thank me later.

 

That's what I was initially thinking of doing. Any idea what it would be making at the crank once it's boosted?

Another question: How hard would it be to do a 1.8 Rear End swap, to swap do I just need to swap drive lines, axles, differentials... is that it?

 

1. we dont measure horsepower at the crank, so dont reference that number.
2. no idea, too many variables.

a third grader could do a 1.8L drivetrain swap.

 

All of it.

Engine power in this context will vary depending on many variables- most chiefly are the fuel and ignition management solution which you employ, followed by turbo selection, whether or not you fit an intercooler, and so on.

For a "typical" build, using fuel injectors in the 440-550cc range, a Megasquirt or similar, and maybe something like a GT2560 turbo, I'd expect to start somewhere in the neighborhood of 200-220 HP (at the wheels) running perhaps 10-12 PSI, with a bit of headroom left.



It's actually pretty simple, especially if you get the axles with the outer hubs still attached. The only part of the swap that can be taxing is installing the axles into the diff, and this is made easier if you can pick up a set of the early style two-piece axles (I think they changed around '97). This way you can pre-install the stub into the diff with a BFH.

 

To address the other part of your question . . . can the car structure take it . . .

Poke around underneath. If there is little rust and not a lot of obvious broken spot welds or cracks, I wouldn't hesitate. These cars are extremely overbuilt for street duty (which is why they are such great race cars) and there are lots of good ways to further stiffen the chassis. The condition of the frame rails will also tell you a lot about how it's been treated (although banged up frame rails are easily fixed).

Mine is at 194,000. I installed the turbo about 10-12K ago. I'm on the original 1.6 and it's never been opened. 100% reliable daily driver so far.

 

And the corollary, if there is a lot of rust I'd move on. In the US, there is no reason to buy a rusty car -- we have plenty of areas where you can find rust-free Miatas. An airline ticket is chump change compared doing proper rust repair -- and you never really get it all.

 

What about if the underbody/frame is clean but there's a bit in the trouble spot (rocker panel), I saw that there are replacement panels, if the rust is isolated to the rocker panel then wouldn't that in theory get rid of it?

 

Words of wisdom. I wish I got a perfect shell instead of now slightly rusting one.

 

Just found out it has a sprayed underbody rocket panels are clean. Bringing her home Wednesday, and then the fun begins

 

5 hours till pick up time. Then ordering a "new" 1.8L engine and transmission. Any tips/advice for building the engine?

 

Well guys she's seen better days. Moving her into some shop space tonight or Monday, then I can finally start pulling it apart and getting parts ordered. she's getting all new body panels, not gonna mess with the existing ones. Underbody is clean but the panels are showing some age on them. A couple dents and some rust :( but swap them out and paint them and it'll make a world of difference. Gonna remove my soft top and just go with a hard top. Then comes the engine and trans swap! I'll start a build thread as soon as I get moving