crxguy52

Despite this not being a turbo miata question, there are several great build threads on this forum, so I figured I'd ask here.

I've been into cars for a while now – I've had a few cars I'd call "quick" (IE, S2000), but none that I would call fast. I finally have the time and money to build a "fast" car, and like many, the answer seems to be miata. I'm looking for a project that:

- Requires some, but not too much fabrication. All bolt-ons would be boring, and building a chassis from a pile of tubes is too much work
- Ideally a convertible, going fast is more fun topless
- Is comfortable-ish on the street (trips of up to 4ish hours at a time, I don't have a truck and trailer) – this means AC and a top are musts (IE, no permanent convertibles)
- Is "fast", which is definitely subjective. Something in the 7 lb/hp range.
- Is fun at the track 2-3 times per year
- Won't break the bank – total cost of ~$20k once everything is said and done

I think a LFX Miata meets all these goals without blowing the budget. V8 miata crossed my mind, but based on what I've seen it's going to be an additional $5k for the drivetrain (LSx + trans is ~$9k, whereas LFX + trans is $3k). I've also looked into kit cars, but the interior quality and body panel fit leave a lot to be desired. A few questions:

1. I know people here are probably biased, but do any other project cars come to mind? I'm starting from scratch here.
2. For the LFX drivetrain, do I buy a doner and strip it or buy engine + trans + harness + ECU separately? Looks like a wrecked Camaro is going to be $5k, whereas buying engine + trans is in the $3k range.
3. Where do you source your donor car \ engine \ trans?
4. Seems like the V8R kit is designed for the NB (steering rack, fits under the NB hood), so it'd be easier to start with that?
5. Seems like e39 ECU with HP tuners is what most people are using, although I've seen mention of EFI Live
6. What are people's opinions on which software to use?
a. Does an e39 ecu plug into an e39a harness or do they need to be matched?
7. Seems like timing chains are a weak point in this motor, has anyone found a more robust aftermarket solution?

I've read through build threads from griff, Portabull, and The Pass, all of which were super helpful. I've got some more reading to do, but answers to the above questions will help guide my build plan.

rdb138

iTrader: (1)

I'll write more later...but you may want to read my build thread too. It has the answers to some of your questions.

https://www.miataturbo.net/build-thr...-build-100655/

BTW...I really like my LFX, its a very fun car.

crxguy52

Your thread was actually next on my list, browsing it now and it’s super helpful!

rdb138

iTrader: (1)

Answers to your questions:

- Requires some, but not too much fabrication. All bolt-ons would be boring, and building a chassis from a pile of tubes is too much work
There is definitely fabrication with this build. It also lacks any instructions, besides other build threads

- Is "fast", which is definitely subjective. Something in the 7 lb/hp range.
With AC and a semi street build you are probably looking more at 8lb/hp range

- Won't break the bank – total cost of ~$20k once everything is said and done
Depending upon what other upgrade choices you make / how much work you do yourself, 20k sounds about right to me.

1. I know people here are probably biased, but do any other project cars come to mind? I'm starting from scratch here.
I have a run down of miata swaps and my thoughts on those in my build.

2. For the LFX drivetrain, do I buy a doner and strip it or buy engine + trans + harness + ECU separately? Looks like a wrecked Camaro is going to be $5k, whereas buying engine + trans is in the $3k range.
Getting a donor car keeps you from having to buy brackets, bolts, etc. which quickly adds up. I found a car that had all the parts (except power steering parts) in a junk yard and they pulled it as one big assembly for me. I would go this direction so your not buying and searching for every bolt.

3. Where do you source your donor car \ engine \ trans?
My blog has info on this.

4. Seems like the V8R kit is designed for the NB (steering rack, fits under the NB hood), so it'd be easier to start with that?
NB keeps you from needing to cut the hood. Power steering rack is cheap (under 100). You may want to also look at the NC if that interests you.

5. Seems like e39 ECU with HP tuners is what most people are using, although I've seen mention of EFI Live
I bought my ECU from Keisler Automation. It was a brand new ECU with a tune already on it & just works. This is the way to go. Otherwise finding the correct ECU is going to be a PITA / you probably are gonna end up buying a couple to find the right one.

6. What are people's opinions on which software to use?
I would use HP Tuners if I was gonna make any changes, but the Keisler ECU just works.

a. Does an e39 ecu plug into an e39a harness or do they need to be matched?
Unless you are running an automatic, I would stay away from the e39a harness & ECU. I believe Gooflophaze (Portabull's son, who wrote most of that blog) spent a lot of time making his work.

7. Seems like timing chains are a weak point in this motor, has anyone found a more robust aftermarket solution?
I believe the timing chain issue was more with the LLT motor (which was the version before the LFX). Not to say it couldn't be an issue, but I'm not that concerned about it.


Also if you are very serious about this swap...Some additional info I would have liked to have known.
A) This car is a torque monster, just mash on the gas...any gear, any rpm and she just goes. I wasn't expecting this, but I'm a huge fan.
B) I put 3.42 diff in. 1st gear is basically un-driveable and I only use it to load my car onto the trailer. I'd go with the 3.23 for the street & you probably will still also use 2nd most of the time.
C) You're dealing with small boutique companies making the parts you need. Things take months to receive, and certain vendors take weeks to respond to emails / phone calls. You will receive little to no instructions, and about every part had some sort of issue that requires a little modification to work. I found Andrew at Keisler Automaton awesome to work with and his parts always worked. Not LFX specific, but SuperMiata also sold parts that just work. I'd recommend buying parts from those two first whenever possible.
D) Electrical, especially how you want to handle the gauges. Know your approach early on. I built my own harness. It's a bit time consuming, but not hard.
E) You will end up taking THE ENTIRE car apart. For some reason I wasn't expecting this. I believe the only parts I have not removed or modified (yet) are the trunk hinges, rear tail lights & rear bumper. (seriously not exaggerating here)
F) Tools. I started with most of the tools I needed, but I've spent over 2K buying tools with this build, expect to buy specialty tools you don't have. The biggest for me was welding equipment. If you don't have it, spend the 1000 bucks and buy, welder, bottle, cart, hemet, gloves, etc. You will end up welding stuff all the time. I also would have purchased 2 grinders right off the bat, one for a cut off wheel & the other for a flap disk. Huge time saver. Another thing I would buy is a metric tap and die kit (or at the very least) 10 to 15mm taps to fix any threads that get messed up along the way.

Don't let the above scare you off. It's worth it in the end. Anyway, ping me if you have any questions & If you live around Atlanta, happy to show you the car / go for a ride.

crxguy52

Thanks for taking the time to write such a detailed response and your offer to help! I'm in NC, if I'm in your neck of the woods I'll take you up on a ride. Definitely serious about taking this on, I might message you with more specific questions as I encounter them. Thanks for documenting your build in such detail, it's super helpful!

I only brought up the timing chain since griff seemed to have an issue with his, but after some more searching it seems like that might have been an isolated incident.

Seems like my first step (outside of planning) will be to locate a full drop-out from a car. As much fun as it would be to strip the Camaro myself, I think it adds a lot of complication. I'll see if I can get the gas pedal as well. Has anyone tried to include the BCM to make the alternator charge properly? I haven't gotten to that point in your build thread, but Keiser offers a bracket for an aftermarket alternator, so it may be more trouble than it's worth.

I'll also need to buy a welder, any recommendations? I know someone who bought a Yes welder which is an all-in-1 welder + plasma cutter, which means it's probably not good at any one of those things . After that I'll have to locate a NB / NC Miata shell, ideally with a blown motor.

Edit: you don’t happen to have a pdf of the Camaro manual, do you? I was planning on buying a 3-day subscription and saving all of the relevant sections, but if you’ve already done that it would be helpful

rdb138

iTrader: (1)

Definitely feel free to send any requests if you have questions. I think most of the other LFX guys aren't on as much as they use to be. You will want to look at Luke G's build too. He has an LFX Exocet build on here.

You may want to order the front subframe & rear from V8R once you have figured out your Miata, then go looking for engine / trans etc.. It took a few months to get parts after ordering. You have time then to find & buy the engine / trans. (FYI...he generally runs a sale during July 4th and Black Friday, no guarantees, but if you can save a buck...) Oh, something else I thought of, the 2014 & 2015 Camaro (maybe 2013) have the oil pan you want to use. It's a bit more shallow and sits 1/4 below the subframe. My understanding is that the 2012 oil pans sit an inch or so below the subframe.

I don't believe anyone has tried to hook up the BCM for the alternator. I have a race car and a much lower power demand, but I run a 3lb Lifepo4 motorcycle battery and never had any issue with it (even in colder weather). I was worried about it to begin with, but its been fine with multiple starts. It's charging the battery at 13.4 volts on average, so a bit low, but seems to work fine for my purposes. I do know a weak battery will turn over the engine fine, but will not start the car due to the high pressure fuel pump, so you definitely want a strong battery. I think Luke G did the brackets and aftermarket alternator, if memory serves, it was good for weight savings and also fit better. I would probably go that direction if you choose to upgrade unless you wanted the BCM for some other reason. (Additionally, I did not have to clock my alternator so it would fit like some guys have. Mine came out of a 2014 Camaro.)

I bought a 140 Hobart Mig welder. Its about as simple as it gets and will weld up any thickness metal you should have in this build. I wished many times I had bought a TIG setup so I could weld aluminum, BUT I'm probably just now getting to the point I could attempt to weld aluminum. I will say using gas made welding the thin sheet metal so much easier and definitely worth that price.

I do have a PDF of the Camaro manual. It's big, but let me try and send it your way.