Turbo a high mileage miata
 

Hey guys, I recently picked up a well maintained 230,000 mile 1.8 miata and I'm trying to understand what I can do with it. From what I understand it has been rebuilt and all the hoses and belts have been done. Should I turbo it? I'm not looking for anything crazy just a little bit more fun.

Do you know what the extent of the "rebuild" was? If it was just hoses and belts then those are the basic maintenance items. For me, a "rebuild" would go much further. I would ask you some questions to dig a bit deeper;
- Is the original radiator in place (and, if so, has it started discoloring)?
- Are the original coils, wires and plugs in place (and, if not, when were they last changed)?
- Have you had (or will you have) an oil analysis performed (to understand the state of wear of the bearings are)?
- Do you know what the fuel and oil pressures actually are (to know whether they are up to the task of a turbo application)?
- What is your budget and what is your appetite for fabrication?
- Are you planning to use an aftermarket ECU (and if so, are you ready to dive head-deep into tuning)?

I'll stop here, but you get the drift. (Successfully) turbo'ing a car is more than slapping on a snail and punching the throttle. If your base platform is up to snuff, then you'll be off to a good start. If not, then your initial goal should be to bring it up to a sufficient level to support turbocharging.

Beyond that, adding power will quickly uncover deficiencies in other areas; brakes, suspension, tires, drivetrain, etc... Be prepared to discover and fix those deficiencies. Your car is a "system" with lots of interconnected pieces. Change one part and others may suffer.

I see well I do know it has a resurfaced head but all of the information u just gave me is very helpful in giving me a way to analyze if my car is ready for a turbo. I plan on installing a ms3 and getting the kraken turbo kit I will buy a new radiator and fans for it. I don't plan to just slap it on I understand what needed for it to work I just don't have the knowledge or resources to fabricate or the understanding of what i need and how I should check the health of my motor. Side note it is also my daily driver.

Compression and leak down tests are a good way to know a little bit more about the health of the motor itself before boosting it.

You are clearly a newbie to this game, and that is not (yet) a hanging offence.

You are a newbie who asks good questions, a trait that portends a productive future, a trait that some newbies lack unfortunately.

You are a newbie who wants to turbo his DD - a high risk move!

So a slow and cautious approach is a sound approach to this venture. You will need deepish pockets, and a lot of learning (especially if you plan DIY tune). Asking questions is one way to get the learning, the other is to read the build threads here that document builds of varying complexity and power goals - from V8 swaps to low boost turbo'd and supercharged street cars. Don't just read about people doing what you propose to do, also read the people who are pushing boundaries - firstly it is interesting, second you learn what the limits are and how to manage them, and thirdly you might end up doing something similar down the track.

Good luck!

Don't have much useful advice to add aside from mentioning again that you can essentially learn everything from A-Z about building a turbo Miata from threads that already live on this site.

Do all the engine health checks including a leak down and compression test. I turbo'd my daily Miata back in highschool and the key was careful planning/research and doing it incrementally. Still was a bigger undertaking than expected but sounds like you may already have a grasp of the basics. Here's 2 links to threads that you'll be able to branch off from for expectations and parts/systems to learn about.

Noob thread:
https://www.miataturbo.net/diy-turbo...-build-102653/

Less noob thread. Disregard the 300hp+ goals but good read for perspective:
https://www.miataturbo.net/diy-turbo...-105444/page3/

Do you guys think I should just try to find a lower mileage 1.8 engine to drop in or just do a rebuild? if its a rebuild please let me know what that would be to get my engine to a sufficient level for turbo. Also these are my plans for the car before starting the turbo stuff...

kensei k1 wheels and extensa hp II tires- 1,065$ 1
tien coilovers -854$ 1
EBC brake pads -95$ 1
Cobalt exhaust -500$ 1
AWR motor mounts-240$ 1
Powersport brake rotors-231$ 2
Flyin miata clutch level 1- 429$ 2
mishimoto radiator and fans- 520$ 3
Godspeed camber arms front - 212$ 3
Godspeed camber arms rear -212$ 3
flyin miata fuel filter-37$ 3
Flyin miata feul pump kit-109$ 3
skunk2 intake manifold- 400$ 3
Destroy roll bar-561 4
Strut tower brace- 123$ 4
Ms3 pro- 1300$ 4
Total-6,917$

Mileage is just a rough indicator of health. If it's best to get a new engine totally depends on the tests and your mechanical aptitude/patience. Can't really give advice without some numbers, but from your goals, it sounds like you shouldn't bother with any internal *upgrades*, just maintenance like rings/hone/bearings if you take it apart.

On the list of parts, here's some tips:
- No need to upgrade rotors. This is basically reserved for people tracking their cars competitively.
- Skip the Mishimoto rad + fans. You can get a big generic Miata aluminum radiator that works essentially just as well off eBay for <$100. I ran one at 250hp for years. Also no need for new fans. The OEM ones actually work great, better than the Mishimotos afaik.
- If you read anything on here, don't get the godspeed camber arms unless you have an affinity for totaled Miatas and/or stance cars. Do some research, plenty of cases of those and other cheap arms snapping from potholes.
- OEM and similar strut tower braces do nothing.
- I'd recommend a Walbro 255 pump for safe headroom and some injector clinic, injector dynamic, or flow force injectors when you want to start tuning.
- Deals on used MS3's pop up every once and a while for some good savings so keep an eye out on the classfields.

thanks this helps a lot i'll look into these and update my list. Im planning on sending my oil to get tested and i'll do a compression and leak down test soon and get you guys the numbers thanks a lot.

also what size injectors do u think is a good size?

This is like asking how big of a condom you should buy. You've got to figure out what you're working with and find the size that fits your needs. A basic ~200whp, stock block miata should be good with 400cc's. Most built motor, e85 miatas will be on 1000cc injectors or bigger.

I agree with Jumpster's suggestions, but I'd scratch the intake manifold off the list too unless you're going for big power.

What year is your miata?

97

Worth noting also, and this is information that can be found all over this site, your stock block and 5 speed transmission are good for up to ~250whp. If your power goals lie above that, you're going to need a forged bottom end and transmission swap (6 speeds are good for ~350whp and BMW ZF transmissions are popular for power levels above that).

Essentially, there's power level tiers for building a turbo Miata. Sub-250whp is the least expensive, least intrusive, and probably most popular. Once you go above 250whp, there's a substantial step up in cost, and again if you want to go higher than 350whp.

You first want to decide how deep you want to go with this project and choose your turbo's supporting upgrades accordingly. I.E. there's no reason to buy 1000cc injectors, a DW300 fuel pump, and huge turbo if you don't want to swap your transmission down the road.

Reading the sticky'd threads on this site will give you a really good idea of what you do and don't need.

thanks this is exactly what I'm looking for. my goals are for 220-250 whp so once I do some test I will be able to see if I need to open up my Engine and fix things. Are there any threads that show supporting mods needed for 220-250 whp because I can't seem to find any. thanks.

There are lots and lots. Look at the "Useful posts" tab under beginners luck on the forums here. Also the sticky'd threads in the Engine Performance section have a lot of wisdom.

Hold up. Hit the pause button.

First, there's nothing inherent in a high-mileage engine that makes it no good for boost. Just make sure the engine is healthy like others have said, get your maintenance baselined, then you can gather parts.

Try to avoid the basic "what injectors do I need" type of questions. You need to invest some time reading. The path to success is one of two paths: Either pay a pro, or become your own pro. Becoming a pro is a lot of work, but taking the time to do it is immensely rewarding.

Read a bunch of build threads. I recommend this because you WILL see yourself in some of these people haha. It gives you context behind the answers you read here. Don't read mine unless you just want to see ultimate struggle bus. Here are some of the more helpful build threads:

https://www.miataturbo.net/build-thr...ta-ever-62679/

https://www.miataturbo.net/build-thr...ack-lap-80308/

https://www.miataturbo.net/build-thr...-thread-81161/

https://www.miataturbo.net/build-thr...ru-td04-74776/

In addition, read the articles on our Tech Guide page. https://949racing.com/supermiata/tech-info/

There's sooooo much information there. Most of my job answering people's questions results in me referring them to information on one of our product pages, or on that tech guide page.

Good luck!

thanks alot I can't believe i have gotten so much great replies. I think im just going to go with a k24 swap insrtead once i ha e another car and do supporting mods for the time being.

this is the way

cool i feel like it will solve most of my problems somewhat.

Quitter.



Lol.