Engine Management for VVT ?

[Quiksilver]

What kind of engine manangement systems are out there for a naturally aspirated 02 NB with VVT? Are there any out there that will do anything to improve torque/HP without having to by a new fuel system (rails, injectors, pump)? Is a wideband O2 a necessity? What about MAP sensor?

Can you reasonably get better performance on a budget with any of these systems - can they work as a first step in the building block process- or should you do many other things first?

I've been following the Greddy Blue thread on M.net and it's quite interesting, but I admit I don't know much about any of this.

[mistanfo]

Hydra will play nice with the VVT. Don't know about any other offerings, though I am sure some of the others do as well. You might check out the MS PNP guys to see if they can offer control of it. Certainly less expensive (though also less powerful).

[mistanfo]

A quick check of the DIY PNP site shows no current support for the 01+ Miata. Oh well. Stay tuned, or even write them, they do respond to what the people want.

[ChristianL]

Might want to ask Chris Rummel. I remember him saying he had a lot of experience with the AEM standalone (can't remember what it's called right now).

[thebeerbaron]

A conventional MegaSquirt could do it, but you'd probably have to go MS-IIextra, which isn't a bad idea anyhow. All of this assumes that the VVT is just an on-off switch, and not some infinitely-variable thing based off a voltage curve...

I haven't checked on the miataturbo forums, but they'd be the ones who've done it if anyone has. In my mind, it should just be another output pin tripped at a specific RPM. You'd have to spend lots of time on the dyno to figure out where that point is though.

Also remember that on certain NBs, not sure if its 99-00 or 01+, the alternator is controlled by the ECU, so backdating to a NA alternator may be required.

Honestly, I don't know how much the 01+ VVT does for power, especially with boost (which I assume you're dreaming about, since short of a V8, there's no other sensible way to add power to these things). I tend to suspect such things are emissions related. Switching to a 99 head could simplify things and give you the superior flow that all the turbo-nuts rave about. But see below first before you change anything...

Getting the car running smoothly on an aftermarket ECU is a great first step to adding boost. Once the car is working great with the ECU, adding new parts is simple, because the fueling portion is already proven to work. You add the ECU and a wideband, spend a few days/weeks (months/years if you're me) getting it all working together. Finally it all works great and you have a good base tune. Woohoo! Then let's say you're upgrading to a massive turbo and matching injectors. You add the injectors to the NA engine, tell the computer you're using new injectors, and your old NA tune now works with the new injectors (you may need to tune idle, but most of it should be OK). Run it for a few days, prove that it's working great. Then add boost. You tighten the last bolt and the car starts up the first time, because you've already tuned in the injectors. You'll need to tune fuel now, but since you'll already have the wideband hooked up and running, that's just dyno time or long drives with a passenger and a laptop. (Note, this is all hypothetical, but makes a lot more sense than adding everything at once and not knowing if it's your turbo that's FUBAR or your WBO2 or what).

My recommendation? (being that I live hundreds of miles away and can't be shanked for my bad advice) Get the MS-IIe, get it running without VVT, switch to the 99 head, and go hog wild.

I can't speak to the power gains of an aftermarket ECU on an NA engine, but Mike Junk can. I did mine as an academic exercise when I was under-employed. It's been over two years since I started the project, but I'm maybe one solid weekend of wiring away from running on the MS-IIextra. It's been a lot of fun and frustration.

[Sam Powell]

I have done what you are talking about with another car, and believe me, it is not that easy. In two years I never got it running really right, with excellent response in all RPM and load ranges, and good drivability, for many long and varied reasons. I finally gave up on it. I haven't driven the car in over a year.

It takes forever to get it really tuned well, and I am convinced it is not its best without a dyno and someone who really knows how to use it. The OEM ECU maps are developed with budgets in the millions of dollars. Those who say it is easy are either trying to sell you something, or haven't done this themselves to a really high level. I;m sorry if someone out there is offended by that last comment, but I hate to see you take a car that is running pretty well, and mess with it until it doesn't. I will share more on this story if you are interested.

Sam