I have so many browser tabs open and I've read so much in the past few weeks it makes my head hurt. Looking for some input from the gurus; If this needs to be moved to ECU go ahead, I was torn on which section to put this in. Some of the questions are ECU related, but they're in boosted applications.

My car is a '92 Miata. Has the 1.6 in it with a Greddy kit, fmic setup, vortech fmu, the basic setup. No standalone of any kind. I pulled the whole kit out and was planning on refreshing the 1.6 and upgrading my dp and keeping the greddy setup...however:

I found a deal on a built 1.8 from a '96, so i scooped it up. Specs:

Manley Forged Rods
Supertech Forged Pistons
ACL Bearings
ARP head studs
Cometic head gasket
Port n polish headwork
Bell Engineering turbo manifold
Manifold studs
Turbo studs
S14 t28 bb with gt2560r chra - .60ar comp, .64 turbine
Hallman MBC
Bell Engineering 2.5" separated gases downpipe
Tial blow off
DSM Blue tops
2.5" charge piping
Fmic
Megasquirt PNP version 1
Speed density

I plan on relocating the Tial to the cold side piping, it's hot side right now.

It came with a Megasquirt PNP MM 9697 v1 included. From my research, the pnp for the 96-97's is basically useless to me if I put this motor into my '92 that obviously has a 1.6 harness. It *may* work but I'd lose control over several key items and its just a bigger headache than it's worth.

Question #1: I'd be better off selling the PNP mm9697 and just getting a PNP for a 90-93 correct? If so, am i better served spending the extra and getting a pnp v2?

Question #2: Say i go with a pnp v2 for the 90-93. This 1.8 motor obviously has the vtps on it and I'm going to want to take advantage of that. If I'm using the 90-93 pnp and harness, I'm guessing I will have to modify the pigtail from the 1.6 tps to work with the 1.8 vtps correct? Then just select the vtps from the megasquirt options because it's designed to accept a vtps signal? I've seen a few how-to's on this but none of them very clear. Can someone point me to making the 1.6 harness work with a 1.8 vtps?

Question #3: Companies like Flyin Miata have instructions for this swap, but almost all of it is based around NOT having a standalone. So you need to run an adapter plate for the 1.8 throttle body. With a standalone, things like using the adapter plate to be able to use the 1.8 throttle body isn't needed correct?

So if you have a 90-93 chassis, using a 90-93 megasquirt PNP, what are the key items you will undoubtedly have to address that the megasquirt can't account for or deal with?

1. Extending CAS wiring
2. Using 1.6 Coil Pack Necessary?
3. Thermostat sensor location?
4. Feel free to correct or modify my thinking here....

I'm here to continue to learn, I appreciate the guidance ahead of time!

And a bonus random thought: According to Garrett they suggest rotating the chra on oil/water cooled turbos 20 degrees off horizontal to aid with thermal siphoning during cool down. Most things you see/read, people stress having your gravity oil drain perfectly pointed downwards. This obviously causes conflict. Looking at the setup on this motor, it follows the school of thought of having drain pointed straight down which in turn causes the water inlet/outlet to be straight across. So what do you guys with oil/water cooled turbos consider the proper train of thought in this matter?

 

Too many questions. I'll answer some random ones.

Sell the 96-97pnp. If you have to ask then you don't want to try and adapt it.

Your 92 is already wired for TPS. Just hook the 1.8 TPS up correctly.

Water cooling really doesn't matter that much. Don't boost into your garage and you will be fine. Hook it up if you want but plenty of turbos are oil cooled only.

The fm adapter plate is to run a 1.6 TB on a 1.8. You don't need to do that.

 

I know the 92 is wired for tps. But I'm talking about using a variable tps....if I do that I'd need to modify the pigtail from the 1.6 harness no? The factory ecu doesn't recognize a vtps signal but megasquirt will. So would the easiest route be to find a 1.6 automatic throttle body (vtps) and use the fm adapter plate?

 

Any variable tps that goes on the shaft wired to that plug will work.

Its up to you to decide which one to use and how.

Dann

 

So if I just wanted to use the 1.8 tb and vtps that's already on this motor, what's the process for making the tps plug that's already on the 1.6 harness work with it? Pretty sure they're different plugs.

Of course using PNP after the fact.

 

Repin the 1.6 harness for a 1.8 connector? Cut a pigtail off a 1.8 harness and use crimp butt connectors and heat shrink?

You just need to get the TPS power, signal, and ground.

 

Buy the right plug.

Wire it to the TPS port on the megasquirt using the ECU harness wires already there.

How depends on what megasquirt you use.

 

Using the pigtail from a 1.8 harness and soldering it/heat shrink was my initial thought but I didn't think the wiring was that straightforward/shared from the 1.6 pigtail. If it really is just a matter of connecting those three wires together, then that's an easy solution. Thanks

 

Thanks for the reply. I'll be using a PNP v2 for 90-93.

I see in the response above I can just steal the pigtail from a 1.8 harness and solder/heat shrink it to the wiring that fed the 1.6 tps plug. Didn't realize it was that straightforward.

 

Well, that's half of it at least.

 

I'm down to learn the other 1/2 if you care to explain. 1.8 into a 1.6 and Megasquirt is new to me, so I appreciate the guidance. I'll in turn contribute the knowledge on to others!

I'm assuming the part I'm not thinking of is on the megasquirt side? If it's a PNP setup and I'm just plugging the harness plugs directly into the side of the PNP box, what is it that I'd be modifying on that end?

 

No it would be to use the 1.8 throttle body and wire that TPS to your harness.

 

1.6 doesn't have vtps, so mspnp will ignore all 3 wires in stock form.

I don't know what to tell you from here, the link to the guide for adding vtps is dead.

Edit: nevermind, just took more than 30 seconds of googling
http://www.megasquirtpnp.com/docs/mspnp_g2_mm9093.php

 

If the turbo was designed for water cooling, you definitely need to have the water lines hooked up. Yes, there are some that are oil cooled, but the CHRA design is different. That said, I don't think that's what OGWar was asking.

While the oil drain needs to be a constant downward slope, it can easily be 20 degrees off vertical and still work properly, so you're not trading off convection cooling for proper oil drain. That said, I don't get the impression the tilted convection cooling setup is all that critical -- it basically just stops water from boiling in the turbo when you shut the motor off. My 2560 boiled water after shutoff from day one, and the bearing was just fine until it ate a throttle body screw, 60K miles later.

--Ian

 

Very interesting thread as I am doing a 2003 complete swap into a 91. At this point I am also leaning towards a 91 mspnp and wiring up everything into it instead of switching the whole harness.

 

yes. MSPNP2, DIYPNP, MS3x, MSPNP-PRO, or bust.


yes. yes. there's plenty of diagrams for this flating around, this is silly easy, ask the question again once you're ready for it.


It depends. Keeping the 1.6L TB is also smart because you dont have to also figure out adapating the idle valve as well as the vTPS...


1. probably not.
2. unless you wire something else in.
3. wtf is a thermostat sensor? You mean teh thermoswitch on the front of 1.6L motors?



quit worrying about completely trivial BS. Link to source...

 

Thanks for the reply Braineack. I may contact you for a diypnp built for using the 1.8tb, icv, and coil pack instead of going the pnp route.

If I use the 1.6 coil pack on a 1.8 motor, I just verify that the orientation of coil->cylinder # is the same as it was when it was on the 1.6 motor correct, since the 1.8 is arranged differently.

Yes I meant thermoswitch, sorry I mislabeled that.

Here's the link to Garrett's discussion on oil/water cooled turbos I was referring to, I thought it was an interesting read: https://www.turbobygarrett.com/turbo...er_Cooling.pdf

 

nothign changes between the 1.6L and 1.8L as far as spark/firing order.

The 1.8L coilpack just happened to be arranged slighty differently. You'd put your spark plug wires exactly as they are right now in the new motor.

if you're running MS, the thermoswitch matters not.


temp difference of 25°F from vertical. I'd much rather have my turbo be 25°F warmer after shutoff and a oil drain that works well...

There's no way youll be able to plumb the turbo "optimally" to even bother. The outlet you'll be using is already lower than the turbo ports.

Garrett also used to say never rotate turbo past 15° else it would degrade oiling.

 

So pull the 1.6 coil pack off and throw it into the 1.8 with the plug wires/tubes exactly the same way it was on the 1.6.....disregard how the 1.8 wires were orientated. Got it.

Yeah sounds like Garrett has differing opinions. I too would rather avoid oil buildup inside the turbo and all the fun that can lead to. I just had never heard the 20deg principle before, every oil/water cooled setup I've ever seen has always focus on having the drain straight down which left the water setup horizontal.

I'll be in touch Braineack to discuss MS options, but I'll save that for PM.

Thanks for the replies everyone, I'm learning.

 

Looking at it, running a 90-93 COP conversion, like one from Fab9 tuning, eliminates all the coil pack swapping concern and is honestly a better option if I'm planning on north of 15-16 psi. Would you agree? I don't see any notices that people running MS run into issues with the Fab9 setup.