Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   The Definitive "VVT swap into 90-97 chassis" Megathread. (https://www.miataturbo.net/engine-performance-56/definitive-vvt-swap-into-90-97-chassis-megathread-80469/)

Leafy 08-28-2014 02:06 PM

If you have a standalone you probably have it wired so the ecu drives the tach even on the 94.

curly 08-28-2014 02:17 PM

That's what we're finding on our MSM swapped '92. In order to have a tach with '01+ coils, you need to have a tach output pin on the ECU to go to the cluster.

FYI: For those of you running Gen1 MSPNPs, DIYautotune will do the mod for a tach output pin for $75 once you ship it to them. I believe the schematic for a DIY circuit is floating around here somewhere.

I'm fairly certain Gen2 MSPNPs already have a tach output pin.

curly 08-28-2014 07:33 PM

Note: this thread is meant for standalone ECU replacements, such as MS and AEM.

For those of you wanting to use a stock ECU, please keep the discussion in this thread:

https://www.miataturbo.net/engine-pe...athread-80666/

But to sum up: stock ECU won't see a tach signal with '01+ coils, and it'll kill itself within a few seconds.

Remember, DON'T discuss those issues here.

Ben 08-28-2014 09:12 PM


Originally Posted by curly (Post 1162019)
FYI: For those of you running Gen1 MSPNPs, DIYautotune will do the mod for a tach output pin for $75 once you ship it to them. I believe the schematic for a DIY circuit is floating around here somewhere.

I'm fairly certain Gen2 MSPNPs already have a tach output pin.

Only 90-93 Gen1 MSPNPs do not have a built in tach output. The Gen 1 94-95 and 96-97 already have it built in, as do all models Gen2 and Pro PNPs.

Example tach circuit for 90-93 Gen 1 is shown here:
MS1/Extra Hardware Manual

In most cases, I'd recommend purchasing an aftermarket tach adapter before sending an ECU in to be modified. Cost would be about the same or less and would eliminate down time.

TheBandit 09-04-2014 09:09 AM

In the event that you plan to keep your 94-95 block and simply update to the VVT head, is it still recommended that I update to the crank trigger setup instead of the CAS that is on the original head? I certainly understand that new ignition (in my case I will upgrade to COPS) and VVT actuation will need to be wired in. The throttle body update is suggested, but not a have to. I'm starting to add up the wiring harness needed for the pigtails along with all the sensors and the difference in cost from just getting an entire 01+ engine gets smaller and smaller. Again, this is all assuming the use of MS EM.

NiklasFalk 09-04-2014 09:38 AM

No way to control VVT without the crank sensor, so why keep the CAS?

Leafy 09-04-2014 09:45 AM

And you'll basically need to replace the oil pump in order to get the crank trigger on a 94-95. IIRC the boss is there so if you're a fucking judo master with a hand drill you could drill and tap it maybe.

TheBandit 09-04-2014 11:21 AM

So I might as well just get a complete VVT engine and stop trying to gather the parts to make it work with my 95 block. I'm still educating myself on the differences required to work with VVT. Thanks for the assistance.

Savington 09-04-2014 09:07 PM

You also get an extra point of compression. Lots of good reasons to just source a full longblock.

Updated the OP to include the answer to your question.

joyrider 09-06-2014 11:09 AM


Originally Posted by Savington (Post 1158403)

1994-1997 coils:
+12v:
94-97: Blue
01-05: Black/White

trigger cyl 1/4:
94-97: brown
01-05: brown/white

trigger cyl 2/3:
94-97: brown/yellow
01-05: black/yellow

ground:
94-97, 01-05: black

1999-2000 coils:
+12v: Black/white

trigger cyl 1/4: Brown/Yellow

trigger cyl 2/3: Brown

ground: Black

Now, do we have to put capacitor as NB2 OEM harness ?

Savington 09-08-2014 12:04 PM

99-00 coils are garbage, you're much better off retaining your stock 1.6/1.8 coils if you are doing a BP4W swap. I specifically left 99-00 coil info off the OP for that reason. :)

my97miata 09-08-2014 04:58 PM

Or you can just go with the Fab9 COP's.

Savington 09-08-2014 05:09 PM

Or you can use the perfectly adequate stock ignition system, vs. upgrading to a system with no benefits.

harrybeachdog 09-08-2014 05:36 PM


Originally Posted by my97miata (Post 1165237)
Or you can just go with the Fab9 COP's.

What I did. They just look purty. Stock bottom end and they're fine, but testing DIYauto has done shows they're not ideal for big boost.


Originally Posted by Savington (Post 1165242)
Or you can use the perfectly adequate stock ignition system, vs. upgrading to a system with no benefits.

They fit in the hole. Every double meaning intended.

Savington 09-08-2014 05:44 PM

Stock coils fit in the hole too...

harrybeachdog 09-08-2014 05:49 PM

I thought the VVT vc had smaller holes for the wires?

Savington 09-08-2014 05:51 PM

It does, and the stock VVT coils fit into the VVT holes. The 99-00 has the same holes as the 90-97, so you would just use stock 90-97 coils instead of the 99-00 coils. If you're going to go aftermarket, skip the fab 9 parts and go straight to an LS2 Truck coil setup.
  • If you are swapping a BP4W into a 90-97, use stock 90-97 coils and wires (preferably the 94-97 coils)
  • If you are swapping a BP6D (VVT) into a 90-97, use VVT coils and wires and wire them per the original post's instructions

harrybeachdog 09-08-2014 05:52 PM

1 Attachment(s)
https://www.miataturbo.net/attachmen...ine=1410213166

Ben 09-08-2014 06:55 PM


Originally Posted by harrybeachdog (Post 1165253)
What I did. They just look purty. Stock bottom end and they're fine, but testing DIYauto has done shows they're not ideal for big boost.

A 3rd party has tested the coils; we have not. The 3rd party test was not flattering. I have no horse in the race, other than the vendor was blaming my ECU for the troubles with his product.

greddygalant 09-08-2014 07:52 PM


Originally Posted by Ben (Post 1162169)
Only 90-93 Gen1 MSPNPs do not have a built in tach output. The Gen 1 94-95 and 96-97 already have it built in, as do all models Gen2 and Pro PNPs.

Example tach circuit for 90-93 Gen 1 is shown here:
MS1/Extra Hardware Manual

In most cases, I'd recommend purchasing an aftermarket tach adapter before sending an ECU in to be modified. Cost would be about the same or less and would eliminate down time.

Ben,
My 92 is the one curly mentioned, would you happen to have a link to an aftermarket tach adapter that would work for such an application?


All times are GMT -4. The time now is 06:40 AM.


© 2024 MH Sub I, LLC dba Internet Brands