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-   -   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/)

oregonmon 11-01-2014 10:42 AM

1 Attachment(s)
Thanks for this thread.

Here's my finished (for now) swap.

Attachment 235543

Reverant 11-01-2014 12:47 PM

Nice and clean. :)

my97miata 11-04-2014 06:36 AM

Love the clean and healthy look of that engine above. My number 1 recommendation would be to cover the header with a TDR heat shield, those things really work.

Morello 01-28-2015 07:57 PM

So I'm just now getting around to starting my swap (life happens) and I figure I would swap the fuel rail before putting my 02 engine in the car. So I have put on the 99 fuel rail with the 1.6 fpr outlet facing up and it doesn't seem like the intake manifold will go on without hitting it, unless I'm just dense. Do I need to bend the fpr tube? I am using the VTCS manifold. Does anyone have a picture showing specifically what on the 01+ manifold needs to be modified to fit this setup?

Savington 01-30-2015 11:34 AM

You need to bend the FPR outlet up, yes. It's easy to do with a deep-wall socket and some patience.

curly 01-30-2015 12:46 PM

Yeah just take your time and bend/test fit/bend/test fit.

The real problem is the vacuum barb. Although you have to bend the 90-93, it positions the vacuum barb in a position that doesn't interfere with the VTCS brace behind the throttle body. This is a metal plate held on with 4 bolts on a VICS manifold, but cast into the upper half of a VTCS manifold. You'll have to cut the inside brace arm off if using a 94-97 fpr.

Morello 01-30-2015 09:04 PM


Originally Posted by curly (Post 1201524)
Yeah just take your time and bend/test fit/bend/test fit.

The real problem is the vacuum barb. Although you have to bend the 90-93, it positions the vacuum barb in a position that doesn't interfere with the VTCS brace behind the throttle body. This is a metal plate held on with 4 bolts on a VICS manifold, but cast into the upper half of a VTCS manifold. You'll have to cut the inside brace arm off if using a 94-97 fpr.

Okay, so no modification of the manifold required if I use the 1.6 FPR in this orientation and bend the tube a bit? I'm more comfortable with bending than grinding haha. :noob: Back to work.

curly 01-30-2015 09:35 PM

Yeah I think that's right. You'll find out soon enough.

Savington 01-30-2015 09:52 PM

You need to grind on the '01 manifold to clear the '99 rail, if you're using a 01-05 VCTS manifold (which you shouldn't be). It's a very minor modification and I've done it before with a hand file.

curly 01-30-2015 10:53 PM

That mod is pretty obvious, grinding for the front long bolt.

I mean the vacuum line off the FPR, it runs right into the throttle body flange brace if you're using a 94-97 fpr.

wkndracr 02-08-2015 12:19 PM

Just wanted to add a note about the alternator if you have a 90-93. On my swap, I simply used the 1.6 crank pulley and water pump pulley and kept the v belt setup without having to mess with alternator pulleys, or buying a 94-97 alternator. Might be an easier route for some.

curly 02-08-2015 12:33 PM

I almost wish I did that. I think ribbed belts look much more modern, but I've never had issues with squeaking V-belts like I have with NB belts. They seem much more sensitive.

Savington 02-08-2015 02:37 PM


Originally Posted by wkndracr (Post 1204074)
Just wanted to add a note about the alternator if you have a 90-93. On my swap, I simply used the 1.6 crank pulley and water pump pulley and kept the v belt setup without having to mess with alternator pulleys, or buying a 94-97 alternator. Might be an easier route for some.

Interesting. I specifically tried this when I built Rover 5 years ago and the 1.6 pulley would not fit on the 1.8 alternator (pulley was too large). I'm starting to think the 1.6 alternator I had was non-OEM. Can anyone 100% confirm that the OEM 1.6 and 1.8 alternators have the same shaft diameter?

harrybeachdog 02-15-2015 06:12 PM

I think the wiring colors for 94-97 coils may be slightly jumbled. On my 96 the trigger wires are switched from what you have listed in first post. Overall extremely helpful thread, TONS of awesome info.

Savington 02-16-2015 02:29 PM


Originally Posted by harrybeachdog (Post 1206364)
I think the wiring colors for 94-97 coils may be slightly jumbled. On my 96 the trigger wires are switched from what you have listed in first post. Overall extremely helpful thread, TONS of awesome info.

The diagrams I have show '94 and '96 both with BRN/YEL triggering 1/4.

harrybeachdog 02-16-2015 02:55 PM

The only way I could get mine to fire, stock ecu or ms2, was with
96 BRN to 05 BLK/YEL
96 BRN/YEL to 05 BRN/WHT

harrybeachdog 02-16-2015 02:55 PM

The only way I could get mine to fire, stock ecu or ms2, was with
96 BRN to 05 BLK/YEL
96 BRN/YEL to 05 BRN/WHT

92mazdaspeed 03-03-2015 10:08 AM

Thinking about updating to the NB1 or NB2 head and was wondering if anyone has found a fix for the NB2 intake cam harmonics problem at high RPM. I remember reading about it awhile back. I want to use the VVT since my ECU can control it and it would also allow me to pick up 949 cams with the crazy 4.. Lift. Plus who doesn't like torque the added torque of the NB2.

wkndracr 03-03-2015 10:24 AM

2 Attachment(s)
For those running a stock VVT motor, what does your spark table look like? I swapped back to an OEM airbox the other day and today I noticed what sounded like pinging while cruising on the highway at 4k rpms if I gave it a bit of gas, although it's hard to tell with all the wind noise. I've been running the same tune for almost a year, and haven't blown it up yet, including a few autocrosses and a track day, let alone about 20k street miles, so I don't think my tune is that off, but I'd like other opinions. Here is my current spark table. I don't remember exactly where I got it from, but it was snagged from a thread somewhere on this forum.

wkndracr 03-03-2015 10:32 AM


Originally Posted by Savington (Post 1204104)
Interesting. I specifically tried this when I built Rover 5 years ago and the 1.6 pulley would not fit on the 1.8 alternator (pulley was too large). I'm starting to think the 1.6 alternator I had was non-OEM. Can anyone 100% confirm that the OEM 1.6 and 1.8 alternators have the same shaft diameter?


Maybe you misunderstood my post. I did nothing to my 1.6 alternator or pulley. I used the 1.6 crank pulley, (with the ribbed and v-belt setup) and the 1.6 water pump pulley (v-Belt setup) and it all worked together just lovely.


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