mx5 vvt head swap.

carlmx5 · Postby **carlmx5** » Sat May 11, 2013 10:20 pm

hello guys, i have a question. I have searched a few forums for an answer but they all end up getting carried away so here it is. Is it possible to drop a vvt engine head into a normal 99 nb engine? I ask because it might end up being easier than a engine swap, and just overall curiousity.

Postby **NitroDann** » Sat May 11, 2013 10:39 pm

Yes. Bolt on.

Dann

carlmx5 · Postby **carlmx5** » Sat May 11, 2013 11:12 pm

Ok sweet. The head is what would contain the vvt? Dont need to change anything else?

Postby **NitroDann** » Sat May 11, 2013 11:14 pm

ecu.

Probably the wiring harness.

Dash possibly.

Dann

Kenstaki · Postby **Kenstaki** » Sun May 12, 2013 12:36 am

Let's say you go and put a VVT head on your '99 block.

Now how are you going to run the VVT using your '99 ECU that knows nothing about the VVT?

Luckily for you, I was contemplating the same thing a few weeks back and gathered some threads on the topic.

http://www.miataturbo.net/general-miata ... urt-62851/
http://clubroadster.net/vb_forum/18-eng ... e-nb1.html
http://forum.miata.net/vb/showthread.php?t=2673
http://forum.miata.net/vb/showthread.php?t=488802
http://clubroadster.net/vb_forum/18-eng ... assis.html
http://forum.miata.net/vb/showthread.php?t=488802

In summary, your options if you decide to go ahead are:

1. Run the engine without a VVT controller, valve timing will not be optimal at all RPMs.
2. Run the engine with an aftermarket VVT controller. The controller will need inputs to control valve timing, such as crank angle, cam angle. So you will need to feed these as input to the VVT controller somehow.
3. Replace your '99 ECU/loom with a '01+ ECU/loom

Kenstaki · Postby **Kenstaki** » Sun May 12, 2013 12:37 am

NitroDann wrote:Dash possibly.

Why the dash?

Postby **NitroDann** » Sun May 12, 2013 12:47 am

Depends if you keep all the loom or still run a cable to the dash.

Dann

carlmx5 · Postby **carlmx5** » Sun May 12, 2013 9:21 am

So if i do go ahead, i just need an aftermarket ecu, which i am getting anyways, and a new dash? Do i need a new dash if i keep the looms or no?

lightyear · Postby **lightyear** » Sun May 12, 2013 2:11 pm

For cost per hp, is it worth doing over normal mods? The vvt engine isn't really more powerful than the non vvt engine. You could get basic head work on your bp4w head for less money and hassle I would think. What is he reasoning for the swap?
I have a complete low k vvt engine, loom and computer. $1250..
Might work out cheaper to do the whole swap if you want to go that way.

manga_blue · Postby **manga_blue** » Sun May 12, 2013 2:14 pm

There's not a huge difference in power between an NB8A head and a VVT NB8B head. But getting more power out of an NB8A head is much easier and much better understood. Cams, headwork and ECU (or any combination of these) on your existing head will give you more power more reliably than you'd get by stuffing around with the head swap.

carlmx5 · Postby **carlmx5** » Sun May 12, 2013 3:51 pm

Oh really, i just assumed having the vvt would make the car more precise in terms of executing power and economy. I thought it would work out cheaper than buying the whole engine and putting it into the nb8a, unless the engine diameters are virtually the same and a perfect fit.