1.6 or 1.8?
 

Ok, I'm in the midst of a search for a miata and I was wondering what you guys think. 1.6 or 1.8? I mean, should I aim for finding one with a 1.8 in it or if I find a nice say 90, should I just get it? I know, "there's no replacement for displacement" and I guess another option would be to replace a 1.6 with 1.8 motor. Anyway, hopefully I will have luck finding a suitable car soon and just give me your input on the subject. Thanks.

I have a 1991, and just built a 99 motor. With all the bullshit and gay ass variables, I wish I had stuck with the 1.6...however I haven't driven with the 1.9l in the car yet. Don't get a short-nose crank motor. Anything you buy with a 1.6 will have a moon trip, so get something you can rebuild and drive to the moon again.

The replacement for displacement is less duty on the boost control solenoid.

So... you plan to boost eventually?
 

If so, the 1.8 cars have stronger differentials. If you start to make real power on a 1.6, you will eat the diff.


It will cost you around $1k to upgrade a 1.6 diff to a 1.8.

The 1.8 will obviously make more power than a 1.6. You may want to lighten the flywheel on a 1.8 to make it as rev happy as the 1.6.

You may also want to consider your plans for frame stiffening. The 1.8 has a few more braces - but these can be added to a 1.6 for cheap.

I guess if I were on the market today, I'd look for the car that was in the best shape or the best value, and then plan my build cost around that.

Hope that helps.

the 1.6 revs faster because it has a smaller ring and pinion. Adding hp will make it rev faster. I have a 1.6 and a 1.8 with 4.10 rear ends right now, the 1.8 is more "rev happy" because it makes more horsepower.

Is there much difference in the NA 1.8 and the NB 1.8? NB has variable valve timing, correct? How does this affect performance under boost?

I have seen a '96 around here listed for $3800.. but the '99's are all in the 7k+ neighborhood. Worth it?

For that matter, are there any differences between the NA 1.8 years that is important for boosting?

If you plan to do a megasquirt, I would personally stay away from the 99+. Less headache with older cars. Unless you find an exceptional NB then go for it.

Let's put it this way. I wouldn't pass on a good condition 1.6 for a worse condition 1.8. Get the best you can get at the best price.

I say if you want a 1.6, budget enough to get a torsen swap.

If you live in an emissions testing state, go obd1 or you'll die of aids.

+1
6" 1.6 rearends all have 4.30 gears
94-97 7" 1.8 rearends (pre-6 speed) have 4.10 gears
1.6 motor is 78mm bore X 83.6mm stroke
1.8 motor 83mm bore X 85mm stroke
The stock 1.8L flywheel is also heavier than the stock 1.6L flywheel.

As others have noted the stock 1.6 rearend is a timebomb in a high output car; I've managed to keep mine together for over 30K miles running 8psi because:
1. I have a 4:10 7" sitting in the garage to put in after I blow the 6"
2. I avoid bonzai 6K sidestep-the-clutch launches (saaad, I know)
3. I don't powershift

If money is no object, a 1.8L motor (especially with a '99 + head) is going to make more hp/liter than a 1.6L motor (unless you can find an ultra rare JDM 1.6 head that has the late model '99+ port configuration). The early 1.8s had considerably larger ports & valves than the 1.6s; the 99+ heads reportedly flow 10-15% better than the early 1.8 head.

There's a helluva lot more to choosing a Miata than engine size.
It's just as easy to make 250whp on an NA 1.6 or 1.8. You're going to have a slight torque advantage to the 1.8, but that's all.

http://www.geocities.com/MotorCity/5361/

You need to have a thorough look through that link.
A 10k mile stripper '90 for $2k might seem like a good deal, until you compare it to a 100k mile sport '99 for $5k.

I've been saying for a long time that my next Miata will be a '99 with a 2860/71 and MS (in parallel). Some recent research is kinda leaning me towards an '01'02 w/Hydra and a 2560. The VVT will be awesome for spool and some mild headwork will flow just as good as a '99 on the top-end. There's been some great headway made in VVT tuning w/Hydra lately. I like the idea of 15psi@3000rpm and 250ftlbs.

Can't argue with that logic at all, but can you pass an OBD-II test with the Hydra?? I've got an OBD-II plug in test here in IL (only for 96+ cars, my '90 is finally test free!) that is a pre-requisite to getting vehicle tags renewed.

I've got the Mitsu equivalent of VVT (MIVEC) on my EVO IX and can tune the map via EcuFlash...sure would like the same capability on a Miata.

If you are going to turbo the car, get a 1.8. There's no reason not to, even if you have to wait a little longer. You will save money and aggravation in the long run. The '94 has the larger 1.8 brakes, a real oil pressure gauge (unlike the '95), OBD-I (unlike the '95.5+), and the biggest benefit, the 7" Torsen rear end (unlike the 90-93). When I was shopping for my car, I knew I was going turbo, so I didn't even consider anything that wasn't a black '94 with a Torsen.

So, the best thing to do seems to be waiting for a 94 b/c it is 1.8, has a torsen diff, is OBD-I, and has larger brakes. I really don't care the color or condition of the exterior to a certain extent.

I don't think ALL of them have the torsen..... right?

No they do not all have a Torsen, but they do all have the larger 7" rear differential. Some of them are open some are LSD.

How do you tell if it has a torsen and what is so great about said torsen diffs. I see that you all always recommend them but I don't understand why.

Would you rather have all of your power going to one wheel or two? The torsen's also help you corner.

to be honest, it really doesn't matter. i don't ever wish i had a 1.8 car over my 1.6 car. any one will be great.

The NA RX-7 LSD (see SoloMiata.com for info on all these rearends) is also an option if you can find one. A few people have suggested the RX-7 LSD (it is a clutch type) is stronger than the Torsen for all out drag launches. I'd be happy to find either at a reasonable price.

I thought we'd talked about the proper use of Google.

And take a good long look through the m.net Garage and FAQ and to get a good idea of the information there for all future general questions about Miatas:
http://www.miata.net/garage/
http://www.miata.net/faq/

This is how to spot a Torsen:
http://www.miata.net/garage/diffguide/index.html

Torsen stands for Torque-Sensing... read here why you want one:
http://en.wikipedia.org/wiki/Torsen