Buh-Bye Greddy! Now what?
 

I hit a snag with my '91. The Greddy turbo setup is official broken. The DP flange warped, turbo has significant shaft play and the manifold has a bit old crack in it (plus I think that's warped too as it won't come off the head). The sad part in all this was I thought the studs just needed to be tightened on the DP, after all that fiddling I'm most likely going to miss my VIR weekend in November.

A couple of things to get out in the open, I love having a Miata but I hate having so much money tied up in one. I wasn't using my head when I purchased it. The car came from an older gentlemen that bought the car new and modified it to basically where it is today. That includes the Greddy turbo kit which was upgraded and running 12 psi, 1.8 Torsen, piggy-back engine management, AGX and Ground Control coils, and the list goes on. The "not thinking" part is I bought it for a premium because it was "done" but with this Greddy kit gone I've basically removed / replaced all the parts that made it "done" except the brakes. I'm figuring with all the safety equipment, new tires, suspension, radiator, intercooler, oil cooler, I'm into it for somewhere around $13k. With this investment it'll be closer to 20k by the time I'm done. A lot of money for a small car.

So here's the meat of all this rambling. I need the car to be a reliable track toy. I have gotten into HPDE events and need to continue my learning. I am also going to be taking delivery of my father's 1965 Olds Cutlass that I grew up in and I'd rather spend my time tinkering with that than the track toy. The Miata has 140k miles on it, engine seems healthy and if I were to source a 1.8 for a swap it would probably end up with a full rebuild which takes money and time that I'm not willing to invest since the 1.6 is fine for now.

Here are my list of requirements:

- Must be reliable!
- Power output should be in the 220 whp and 200 wtq range (plus or minus in there)
- Does not need AC or PS
- Must be "trackable". I don't want any long spool times or crazy surges of power if I can avoid it.
- Money isn't specifically a constraint but it needs to make sense. A 20k+ LS swap is not in the picture.
- If I go FI on the 1.6 I'd like the components to be able to port over to the 1.8 for the most part.

Here are the options I'm toying with:

Option 1:
Flyin' Miata FMII kit with Hydra ECU on the old 1.6l
About a $5k investment, should hit the power targets fine
Seems to be reliable
I could swap everything over to a 1.8 later on except the manifold and dp (not a lot of expense in the big picture)
Downside is I'm dealing again with a turbo and all its associated issues (heat, oil delivery, etc.)

Option 2:
Track Dog Racing Rotrex kit on the old 1.6l
About the same $5k investment, will hit the whp numbers but will be short on tq by 30 ft lbs
Power delivery would make it easier to drive potentially
Does not come with a standalone engine management unit
It will be the smaller c30-74 but most things can port to a 1.8. A good build on the 1.8 will reach the 200 wtq and "almost" 300 whp
Downside is low on tq, worried around town driving will be boring and corner exit won't be as great.

Option 3:
K24 swap!!!!
Probably close to $10k, will hit the power numbers and do it reliably
Power delivery will be great and would make it easy to drive
Lots of headroom for more power, probably too much power
A ton of work to do, makes me tired even thinking about it

Besides telling me I'm dumb for investing this much into my Miata, I'd like to hear your opinions.

Here she is after spending way too much time wrapping her:

https://farm5.staticflickr.com/4492/...99175d1a_b.jpg

Option 1: not worth it on a 1.6
Option 2: LOL garbage, not even worth mentioning.
Let's discuss option 3 or some other option.

Garbage because 1.6? Or garbage because old technology and Mazda?

both those things.
spending a whole lotta change on new parts to boost a 1.6 is really a waste. budget setup, you could at least make the budget argument. but when paying 4k+, it just doesn't make sense
just .02

Truth. According to TDR the Rotrex will carry over to the 1.8 if / when that conversion happens. The FM kit will require a new DP and mani which isn't too bad money wise.

Reliable track toy?

Get a megasquirt 3 and the Track Dog Rotrex kit. If you're willing to jump to a 1.8L then either TSE's EFR kit or TDR's rotrex are the most reliable way to make good power day after day without track break-downs.

K24 swap or TSE Kit on a 1.8.

Really the only options I would consider.

Also I wouldn't run a hydra, or any other terrible ecu that fm sells if they gave it to me for $3.50.

Option 3 remains the undisputed winner here, unless you bring a turbo bp into the mixyou only recommend that brotrex mediocrity cause you want to validate your choices.

how about hold off recommending it until you have lived with it for some time and it has been working flawlessly

+1

As usual there will likely be hysterical debate from the 1800 lovers but my impression and suggestion is as below....

My impression is that you already have the 1600. Your not trying for any crazy goals of power and the only problem you have is a crappy G Reddy setup.

Buy a 1600 Manifold and DP from Kraken, Buy a new or used t25 or t28 (small ish) tune and enjoy.

Save lots of money and have fun with what you have. The only unusable part you will have is the manifold and that will have residual value when you sell it IF you upgrade to 1800 later.

We have raced a 1600 for 3years now with class wins, series wins and a National Superlap 2WD Pro Street title.


Having just got back from the dyno with our new built 1800 (and Kraken manifold) and road tested I can confirm the extra torque etc is nice but certainly not a game changer IF cost and fun is your prime focus. The 1600 is a LOT of fun.

Sure an 1800 is the next step and if your competing with them and want to actually COMPETE you will need the same but for track days, road use and fun.....nothing wrong with a 1600.


See from about 6 minutes in for some overtaking fun.

1.8 Swap + MS3 + MKTurbo kit has to be the easy winner here, no?

Also....

"Besides telling me I'm dumb for investing this much into my Miata, I'd like to hear your opinions."

Most of us here have invested lots over time.....it's not dumb, you just have to determine if this is for you and the costs and fun associated with a performance car getting thrashed on track. I don't see any other car NOT having at least these costs. In fact I still consider MX5 to be cheap (relatively speaking, very few cars drive and perform as well on track at any similar cost).....despite having spent decent money these past 3-4 years.

edit. I also agree with 18psi on option 1. if your going to spend big lumps sums. Best on an 1800.

If you want to spend f'all and retain what you have....stick with it.

I think option #3 would be my choice. Its expensive but the K series motor is so good. Honda heads flow crazy well and make easy power. If youre not going down that road just get a T2 manifold, GT28 turbo and get a downpipe fabbed for the B6 motor. The other bits from the GReddy will still work with a different manifold and turbo with a little work. This way you dont invest a ton into the B6 motor because it really isnt nearly as good as a BP.

I daily a turbo Miata. Has enough torque to run the AC! LOL. Actually, it's a really nice daily and squirting around with the turbo is fun. Very reliably in a street application. Coming up on 70K with the turbo (250K total).

For track . . . normally aspirated. Spend the money on track time, suspension, tires and maintenance. That's what will make you fast. Everyone thinks my track car has uber HP. They are crushed when I pop the hood and they see that I'm passing them with 135HP. Emilio published the recipe, it's easy and effective.

Not track reliable at this point.


I think sticking with the 1.6 makes building a track reliable car a bit harder. Mostly due to manifold choices. I would honestly get a MS3, drop in a 1.8 motor, then a TSE EFR 6258 setup. This will get you the power you want at about $5k-$6k. I think it will be the easiest and cheapest route to go.

are you racing to win prize money? is it a track toy first and street car second?
if yes to both, stock 1.6 is fine. get the FM kit and a 2860 if you have a 6 spd or a 2560 if you have the 5 spd. I'm running 3hr w2w mini enduros, all it takes is a 7K redline, hood vents and proper ducting to the rad. you're going to make the same peak power with either before bending rods anyways, 1.8 has more midrange but if you're running the 6 spd,., you should never be below 4500RPM on track anyways. if 5 spd, there will be issues not being in the powerband with the 1.6, definitely get the 2560 to help out the midrange. pretty sure my car with the stock 1.6/2860 would be 2 sec./lap slower with a 5 spd at all the tracks it's running.
-never driven option 2 or 3 so I would have no first hand experience/comments.

After some reading, some lengthy discussions with both FM and TDR I've decided on the rotrex setup from TDR with some options added in for good measure (MS, bigger injectors, etc). In the end I thought the power levels were more than sufficient for me and I just really didn't want to deal with a turbocharger again. The K swap is just way too much money / effort.

well we can't all make good decisions. someone's gotta buy the mediocre ones. lol

I think you'll be pretty happy with it. I just got my full kit in from TDR and after opening the boxes I was even more sold than back when I drove one a few months ago.

option 1: buy a header and intake -- run VIR n/a
option 2: buy a MKTurbo kit.
option 3: go 1.8 vvt.

:)