I've done the mods. I'm waiting to place the MS back in the car along with some other mods to see if it works. Just too bysy at work these days.









(Baro MAP, Dual Tables, Launch Control, Shift Lights, EGT)

 

You show the knock sensor on your wiring diagram. Do you know yet what settings you're going to use for knock retard? Any idea how the stock ECU manages it?

I just got an O-scope this week and I'm going after my engine with a hammer this weekend to see what signals I get. Anyone know the proper way to whack an engine to simulate knock?

Frank

 

Got the ignition going today. Disconnected the MAF, and the car continues to run. Revved her pretty hard in the parking lot just to make sure. And boy, does she rev well...

 

Awesome! Any special tricks involved? What about controlling the VVT?

 

I'll be writing a guide soon. I have a theory that the VVT may be controlled via the boost controller logic. We will see how that turns out.

 

I didnt think we could disconnect the MAF doesnt the VVT use that for its operation?

While were talking about vvt does anyone have any ideas oh how timing should be controlled to work well with boost? (low boost high advance, high boost full retard?)

 

You can disconnect the MAF, the car will continue to run, however the VVT and the VTCS will not be operating. This means reduced midrange torque (VTCS) and higher emmisions (VVT). Like I said in my previous post, the VVT is controlled by a solenoid valve so you may actually be able to use the boost controller code to contro the VVT! I am still researching into the VTCS to see how it operates, however I am not really looking into doing anything with it, as I will ultimately install individual throttle bodies, therefor no more VTCS.

Jim

 

VTCS can be operated by a "simple rpm switch". It only have two modes (thats what i've read at least).

VVT is operated by PID regulating pulse lengths of the binary valve. The CamAS is used as feedback.
If this is anything similar to boost control I don't know. If someone could make code/solutions to tune the VVT things would start to look extremly fantastic.

What would a Double-DIN complete MS setup cost (with a mediacenter+navi it would be a schweet setup )?
Just kidding but you're on to something really nice here.

 

VTCS as is fitted in the NB8C is Variable Tumble Control System, so as far as I know it has varying states, not just on/off. VICS (NB8B) on the other hand, is indeed on/off.

It is possible and it has been suggested for another type of VVT (on a Toyota engine I think, which only had variable valve timing, ie NOT VVTLI) on msefi.com or msextra.com. You don't really need the PID controller to control the VVT, you just have to tune for warmed up conditions because when the engine oil is still cold, the oil pressure is high thus the intake cam is given a bigger phase advance than when the oil is warmed up (and it's pressure is lower).

I already have the said setup? The incarpc cost me about $1200 including fabrication of the LCD in the center console.

Jim

 

As far as I've understood the VVT contol it's continously regulated even to keep the cam timing constant. Longer pulses to advance and shorter to retard (or the other way around). The CAS is used to tell the ECU what the cam timing actually is at the moment (in relation to the crank sensor).
There is no simple pulse lenght that will keep the timing constant in a system like this.

But I have not designed the system, only read posts on miata.net about a project trying to control the VVT. It looks like the Mazda solution is a bit different than what other manufactures have used.

 

It was my understanding that the 01+cars didnt have the VTCS. I will try to track down the reference that put this idea in my head.

 

01-05 had VTCS
99-00 had VICS
90-97 had nothing

 

Anyone know what the maximum advance/ retard is on the intake cam?

I am from a mechanical back ground so a lot of this control stuff is pretty alien to me.

But a friend of mine is looking at ways to filter the stock crank and cam sensors so that they look like the cas sensor outputs. It looks like we have something that works. My main concern is that the intake cam is advanced or retarded so much that the two sensors (crank,cam) do not remain in relative phase, we need to use the intake cam signal as a reset for the crank sensor.

Given that the stock ecu takes timing of these two sensors it seems resonable that the vvt timing range is not great enough to prevent the intake cam to be used as a reset for the crank sensor.

This make any sense to you electrical guys?

 

IIRC it's 50 degrees, 15 retard and 35 advance.

 

but it's half that in crank degrees, so 7.5 retard and 17.5 advance in crank deg?

FM's base map uses 6.0 ret and 12.5 adv at their limits in the hydra.

 

The other way around, 720 degrees on the crank for 360 degrees on the cams.
But if the -15 - +35 degrees is in relation to the cam or crank I don't know.

 

If vvt is unplugged is the cam held at 0 deg?

 

No, it falls to full retard IIRC (it needs regulation/contol to stay at one specific degree of advance/retard).

 

wow. I jus read this now. I must say wow

 

Hey Reverant,

Any updates? have you played with VVT at all yet?