I found a '90 Miata in my area for $1800, that I will be looking at tomorrow or thursday. Unfortunately, it's got the auto tranny, whiich I've decided I would retain if I bought this car...it's the engine that I would replace since it must have high miles and let's face it, it's underpowered. I'm looking for sensible/logical suggestions on a bigger/more powerful 4 cylinder or 6 cylinder (V6?) engine and help in finding any websites that detail the kind of engne swap I'm looking for. I don't want to perform a swap that would seriously undermine the wonderful balance of this car, nor do I want to end up with an engineering nightmare. a good example of an "ideal" swap would be the V6 from a 929 or Millenia.
kcbhiw
Reader
8/5/08 11:03 p.m.
Take into consideration the '99/'00 Miata 1.8. It flows well, has higher compression than earlier 1.8's, practically bolts in, and really doesn't affect the balance of the car.
www.solomiata.com has a wealth of info on various breeds of the B-series engines that will work with the car.
Yeah, I figured the most obvious idea was to go with the newer engine, tho I do remember reading in some car mag that the "changeover" from the 1.6 to the 1.8 can get involved....lots of piddly little details, like differences in emissions control hardware.
I wish there was a bigger "pool" of alternative Mazda engines (I had this idea of keeping it as much of a Mazda product as possible) other than the 4 cylinders, the rotary, and the previously mentioned 929/Millenia V6s.
It's not so bad. I think FM even has a kit to take care of the piddly details. I'd convert to a 1.8, which would be a pretty substantial boost, then if that's not enough, turbo it.
Here is some further and important info.
In the '90 Miata, 1.6L engines mated to 5 speeds produced 116 hp. The 1.6L engines mated to autos produced only 105 hp.
In '94 & '95 the 1.8L produced 128 hp with both transmissions
In '96 the 1.8L went to 133hp with both.
In '99 the 1.8L equalled 140hp then 142 hp in 2001
Source: http://www.miata.net/faq/features.html
http://www.miata.net/faq/miatachanges.html
I think keeping the auto trans in place and adding more power is a bad idea. I do not think it is built for power. I also then realise that you are not just perceiving the car to be under powered, it really is.
I am not sure what is needed to gain the 11 hp (105 hp to 116 hp.) I am not sure if it is an engine issue or an ECU issue. You could then supercharge or turbo charge on top of that.
Seems the hot set up is the later 1.8L's. This will bring you about 30 hp and at your current state of 105 hp, that is like a 30% increase.
If I buy this car, I'm not crazy about the bright blue color, the guy who winds up doing this "conversion" will be one of the guys mentioned in the "Joes vs the Shmoes" article (I won't say which one in case I don't buy the car, and besides, he has his own Miata for sale). For reasons having to do with emissions, I would think the best candidate for years used if I stay with a 1.8 would have to be '94/'95.
How about a built 302 with a C6 trans behind it? I think it fits...
Quickest and easiest solution? A low-boost turbo. The auto 1.6 has a different camshaft profile and lower compression.
I don't know what the power limits of that trans is. The fact that Mazda dropped the horsepower on the auto car makes me wonder.
1.8 swaps aren't that difficult, especially if you start with an automatic car so you can use the 1.8 throttle body and TPS. Yes, FM has the parts you need to make it easy. There aren't a lot of piddly details - most of the emissions equipment from the newer engines simply isn't on the 1.6, and the 1.6 ECU doesn't expect to see it. The basic rule of thumb is that hardware gets changed, electrical does not. So if a sensor is on the 1.8 and not on the 1.6, you don't need it. There's nothing magical about an engine that has bigger holes in the block.
Once you get outside the Miata engines, it's just like any other engine swap. You're probably going to change the transmission anyhow.
stumpmj wrote:
How about a built 302 with a C6 trans behind it? I think it fits...
99% of the 302's out there would never need a C6. A C4 is usually more than enough. Of course, there's always a few one-percenters out there...
Anyway, I vote for anything Keith recommends.
This afternoon I dug out an old issue of the MIATA magazine I have that has an article about superchargers and turbochargers for the Miata. It left me kind of hazy as to which would offer the better performance improvement.
If/when I ever added a super or turbo charger I think I would want which ever one improves low end power response. I'm currently driving an Integra with auto and it really is kind of "lazy feeling" below 2,000/2,500 rpms.
One little tidbit about Miata magazine - the editor got royalties for the Jackson Racing supercharger :) It does explain some of their editorial stance.
There hasn't been any advancement in superchargers for a 1.6 Miata since 1990. There's been 18 years of solid progress on the turbo front.
From the way the magazine read, I suspected the editor was trying to keep several advertisers "happy". The guy that would do a 1.6 to 1.8 on this car....if I go ahead and buy it, has leaned in the direction of turbos before, when I was considering one for my old Civic with a "B" series transplant. Personally, I suspect that just gaining a "few" extra horsepower by trading up to the 1.8 will be enough for me. I have a bad habit of exercising my right ankle a little too much.
