aarongdl

I've wanted to do a boosted Miata since I've owned my first one, especially after owning a boosted GSR (No, I'm not a Honda kid. I gave a turd Miata and like $400 for a boosted GSR. It had so many issues, but it was fun.) Anyways, so in my current situation I've decided to go ahead and go through with my plans of having a turbo miata. I do have several setbacks, and have considered doing a build thread, but even with that, it likely won't be finished for a little over a year. That's fine. As of now, my largest concern with this Miata is reliability. I daily my car at the moment (I cringe every time I take the Corvette out because I live on a gravel road, and driving it every day just isn't going to happen.) Having worked 6-7 days a week, I dont have time to tear the motor down and rebuild it myself, so I will have a shop to do the actual rebuild. I have an end goal of around 300 whp, but honestly I'd be happy with a little over 200.

I'm a rather large believe of the saying "Do it once, do it right." So if it takes me a few weeks longer to have it done, so be it.

THis car will stay my daily for several years to come, commuting to and from work maybe 40 miles a day. (The car does not see over 60mph unless I'm on an interstate on a weekend. I'd like to roll into full boost around 3k. . . but that's for another time.)

Moving on; I've read and lurked for awhile checking out build threads and reading discussions and I think I'm going to do my build in 3-4 stages in the following order:

1) Build motor
2) Install and learn to tune N/A with MS3
3) Replace trans and diff (anything else I need to look for?)
4)Gather turbo parts and turbo setup

Or I could:
1)Build motor
2)Install and learn to tune N/A with MS3
3)Gather turbo parts. (Run relatively low amount of boost)
4)Replace trans and diff
5)Turn up boost

This leads me to the next few questions:

Can I have everybody's opinion on this? Or what they'd do, personally? I'm looking forward to seeing what all of you suggest, including some of the more active members, like 18psi for example. :P
If you could do your build differently, how would you?

As of now, I have the following parts sitting in my room:
Manley Forged Rods
Engine Rebuild Kit

I'm looking to order:
ARP Headstuds/mains
Billet Oil Pump (Have heard iffy stuff on the boundary engineering oil pumps)
8.6:1 Pistons (I am waiting on the builder to tear the motor apart to determine whether I can go with stock bore or if I'd need to have it bored over)

What else am I missing for the rebuild? (Already have new aluminum radiator, coolant reroute. Looking into ATI damper when it makes more than stock power, lol.)

Next questions:

Having work on the head done, what needs done?
This is one of my weaker points, I'll admit I don't know anything about having work done to a head or what kind of springs I need or anything of that sort. If I wanted to rev it relatively high, what kind of work do I need to have done? With a 8.6 piston, will I need a thicker, cometic headgasket? I mean, I'll be running around with a stock motor for awihle with lower compression pistons, I'm sure the thicker HG won't help me out.

Turbo bits;
Looking at a few parts, but I see a lot of the crazy is a GT2871 or an EFR turbo. What's the craze with EFR turbos?
Stay away from the ebay manis (duh) as Begi manifolds? (Those are prone to cracking?)
I imagine as far as fuel goes, I'd go with a 650cc injectors and a Walbro 255.

Thanks for taking the time to read this post and offer me your opinions!

18psi

iTrader: (76)

all depends on what year you're starting with

thirdgen

iTrader: (26)

Ms3 and learn to tune first, the worry about building a motor, or adding forced induction.

aarongdl

18psi, I'll be starting with a '97


My apologies!

I had a base model NB, and sold it. Then quickly decided i couldn't live without a Miata, so I picked up one with considerably less rust!

fig

If you don't have a 1.8 get a 1.8

18psi

iTrader: (76)

97 has 1.8 so that's good, but you really want an nb, and even more so an nb with the 6sp and torsen. otherwise install ms3 and wideband and start learning everything about tuning it

aarongdl

I'm planning on picking up a 6spd, but will most likely keep the NA.

What is it about the NB motors that are much better than the NA if you don't mind my asking?

I know the 01+ introduced VVTi (don't quote me on that.)

Do the '99-00 have better heads? (I've read something about those heads being swapped but I don't remember.)

Thanks for the input so far guys. A diff upgrade and trans are definitely in the works! Would just like to have the motor rebuilt and reliavle for now, but while it's apart I may as well have all the internals put in instead of having it done twice

18psi

iTrader: (76)

Much better head, better chassis, better suspension components, and some of them get the 6sp and torsen rear. Nicer interior, the list goes on.

But engine wise, basically just the head

fig

A obx lsd can be had for around 350, After upgrading washers and hardware it's comparable to a torsen. If you're on a budget.

18psi

iTrader: (76)

You can find torsens for 350 if you look hard enough

ridethecliche

iTrader: (2)

Are you actually going to be happy with just over 200 or are you set on 300? The build plan for the two will look pretty different for the same amount of reliability.

You probably don't have to tear into the engine if you're only wanting 230hp. I mean, it won't hurt matters obviously, but if you want to build it up over time you can stop there and do the engine work when you have a 6 speed and all the other stuff needed to bump it up again.

Can also sell the open diff to someone with a blown 1.6 diff. Won't net you all that much but it's better than nothing.

Now that I'm planning on doing boosty things, I'm self face palming for getting a 4.3 torsen for the 5 speed.

2798jmitch

Sounds like you have a good start on the build, Manley rods and engine rebuild kit is a good start. for the parts you need the arps are a definite. i have heard some things about boundary pumps too but i run one and havent had a problem (its better than cracking stock gears). definetly get a vvt pump because they are higher flow and your going to want that to feed your turbo. i was thinking the same plans for getting stock bore forged pistons uuuuntil i realized nobody makes them in 83mm(stock bore). unless you buy custom pistons. your going to have to bore the block, im doing twenty thou. youll probably want to do all the other typical machine work like chek the mains polish the crank, and most importantly get the whole rotating assembly balanced. as for the head id probably just do a full head job with upgraded springs and valves. maybe even a slight polishing. personally i run a stock head with oversized exhaust valves and i dont think doing a ton of head work is really needed for your power goals. for the headgasket just get a cometic or any mls. i run a .040. the gt2871 will be fine for what you want also. i also wouldnt worry about trying to learn to tune before you go turbo its not very difficult either way just dont be crazy with it off the bat and do your research. theres tons of info on this forum.
Good Luck!

Bill Pence

I'm new to the forum and also considering buying a 99 Miata stock (one owner 75 year old guy) with 54k for $5900 to do a build and eventually an Exocet. No torsen or 6sp though..

ridethecliche

iTrader: (2)

I paid 3800 for mine. It's a 2000 base model which had 103k miles on it. ~6k for 54k miles sounds in line with what I'd expect. That motors probably just starting to get broken in at 54k miles!