Matt Cramer

The delay exists in theory, but is almost infinitesimal. In any case, you will have no problem using the trigger angle and spark latency settings to tune around it.

FatKao

If there is a delay you can just play with the trigger offset till it's true again.

y8s

iTrader: (8)

I think Matt means the delay is on the order of the length of the wires divided by the speed of light (give or take). plus perhaps a couple milliseconds for processing.

Matt Cramer

Yes, there is theoretically a bit of a delay from processing, but it's almost non-existent.

JayL

iTrader: (12)

I'm still a bit confused as to whether they are preset to a certain vvt profile or are they end user adjustable?

engled

It has a base tune on it that will control a 01-05 Miata engine, it is also fully adjustable via a 12x12 map.

Joe Perez

iTrader: (8)

Based on what reading I've done, my impression is that you don't have to do it this way. If you own an MS1, then yes, you can use the box to convert the NB signals to NA format. But if you have an MS2 or MS3, you can just bridge the raw NB cam and crank signals and feed them into the MS as usual, and leave the VVT controller's "NA" outputs disconnected. (This may be wrong.)



Here's the documentation, including tuning instructions: http://www.diyautotune.com/vvtuner/index.htm

Cilff's notes: fully tunable. You can download the software here: http://www.diyautotune.com/vvtuner/files/vvtuner.zip

shuiend

iTrader: (24)

From the little research I have done if I wanted to feed my MS3 the NB signals I would have to build an additional circuit onto my MS board to understand them. Since I am to lazy to order parts and build the circuits I will just use the VVT controller box to feed NA CAS signals to my MS.

When MS3 gets VVT support added in I might look into building the circuits I then need.

Edit: Joe I built my MS back in the beginning of 07 using the KingofLeet mods and then switching to your spark mods. So I am almost positive I would have to build the circuits to understand the NB signals.

engled

The current controller will output to anything expecting to see a NA CAS or the NB crank/cam sensors. Whether it's a MS, factory computer what ever you want to send the signal to. You can not bridge the signals, you have to go through the VVT controller.

NiklasFalk

iTrader: (1)

This then sounds like it would e really easy to attach the VVT controller to my DIYPNP for the 99 (just feed the cam/crank-signals out through the DB15 on the DIYPNP).
In my case I will like to continue to simply swap in the 99 OEM ECU when changing engines for annual inspection.
The whole VVT setup attached to the DIYPNP DB15 makes it real easy to connect (but I'm getting ahead of myself as usual, I don't need to startup until April).

Ben

iTrader: (33)

Almost. NB CMP and CKP are fed to the VVTuner. The VVTuner performs black magic and outputs NA or NB CMP and CKP signals to the stock or aftermarket engine computer. I guess an exception to this rule would be if you swapped a VVT motor to an NA and were planning on using the car's original CAS and engine computer... though it doesn't make sense to use an NA CAS if you have the option to use the NB crank trigger.

y8s

iTrader: (8)

I think i misread and then reread, but you are currently using your NA CAS for your MS3, right? That definitely wont get you far with the VVTuner. It needs at the very least a fixed (cam or crank) primary signal and a moving (intake cam) sync pulse to calculate cam advance.

So I guess in theory you could use an NA cas on the exhaust cam and the 01 cam sensor on the intake cam and be ok. Assuming the NA CAS output matches the NB crank output (and phase). It would just be weird.

HOWEVER, since I know Lars has both the NA CAS *and* the 2001 Crank wheel and VVT cam sensor... it's all moot.

shuiend

iTrader: (24)

I am currently using my 94 CAS for my MS3. I have both the NB sensors and will be hooking those up to the VVT controller. I will then be using the VVT controller to output the CAS signal to my MS because it does not have the actual circuits built to understand then NB signals. I like making things complicated.

Joe Perez

iTrader: (8)

Ok, looks like I was wrong.

Why is this, may I ask? On the Megasquirt, at least, I'd expect it to be insensitive to changes in the phase relationship between CMP and CKP, so long as CMP always stayed within a certain boundary between a given set of CKPs regardless of cam advance.

Or is that the problem? I've not studied the relationship between the CMP signals and the min/max advance settings of the cam. Do they actually cross over a CKP pulse depending on advance?

FatKao

I'd rather keep MS3 on the NA style signals so it keeps the VR circuit free for things like the VSS. As long as it's NB accuracy NA signals I don't see any real reason one would be better than the other.

y8s

iTrader: (8)

Free samples of the MAX9926 from maxim, a half dozen resistors and caps and a 1" square PCB... and that whole area is free.

shuiend

iTrader: (24)

Who thinks I should pull off the top to look at the insides?

engled

Mine looks like this on the inside.

shuiend

iTrader: (24)

Here is a spreadsheet that has what colors go to what pins on the DIYAutoTune harness that they sell with the VVT Controller.

Pin # CCM Pinout Wire Color
1 CMP (CAM) Signal to EMS [Output] green/black
2 CKP (Crank) signal to EMS [Output] white/black
3 CMP (CAM) Sensor Signal Ground [Input] green
4 CKP (Crank) Sensor Singnal [Input] white
5 CMP (Cam) Sensor +12VDC [Output] orange/black I added black stripes on my harness
6 CKP (Crank) Sensor +12VDC [Output] orange
7 System +12VDC [Input] red
8 OCV Control [Output] purple/black I added black stripes on my harness
9 EMS Ground brown/black
10 Shield Ground (EMS,OCV)
11 Shield Ground (CKP/CMP Sensors)
12 CMP (CAM) Sensor Ground black
13 CKP (Crank) Sensor Ground black
14 System Ground black
15 OCV Control +12VDC [Output] purple

Joe Perez

iTrader: (8)

Indeed, the 9924/9926 is about the best cam/crank sensor input circuit I've yet come across. Works great for both VR and hell/opto sensors. I posted a writeup on one a little while back: https://www.miataturbo.net/megasquirt-18/max9924-47243/


What does the input topology on the new controller look like? From the images, it's clearly all through-hole, which rules out the Maxim chips, but is it a dual opto circuit, an op-amp based design, comparators, etc? I can't make out the part numbers on the ICs from the photo which engled posted.