2004GS

iTrader: (1)

If you guys have not seen it yet BRP has suggested a VVT mod that works well with FI applications. It looks like you just advance the vvt sensor by 2 deg, so I guess this would keep valve timing advanced by 2 deg from stock all the time. They claim this was good for 30hp on their top end supercharger system.

If you interested check out the brp forum site or I have a PDF instruction sheet they put out, anyone interested can pm me their email and I will send it to ya.

Things are looking up for the MS on 01+ cars, let’s keep this thread going.

I’m about halfway done the build on my MS. Right now I need to set the jumpers to select between the VR or hall/optical type sensor. Is the VR sensor the one that works with CAS?

Al Hounos

No, set it for hall/optical.

Reverant

iTrader: (10)

Maybe so for an '00 10AE Miata, certainly not so for an '02 1.8 VVT:



Closeup:


Source?

The VVT is controlled by the OCV, the bulgy thingy on the top of the front of the cam cover. As a PWM solenoid, you don't just turn it on or off, though that may seem to work. Also, as the system uses oil pressure to push the actuator (integrated on the intake cam sprocket) which varies with oil temperature, oil type and RPM, you need to work around that too. The stock ECU does this by continuously monitoring the requested advance/retard of the valve phase Vs the actual advance/retard and then applies a correction factor on the next loop cycle. Yes, the VVT control is a closed loop system.

Reverant

iTrader: (10)

Sure, take a look here:

http://www.cardomain.com/ride/2287976/3

Reverant

iTrader: (10)

Although this is the Miata turbo forum, I intend to run N/A.

olderguy

iTrader: (19)

Very Nice

timk

The '99 workshop manual says the fuel line pressure should be between 53-61 psi, and the injector volume 264-328 cc/min. That's quite a big range. I'm assuming it will be pretty much the same on all the returnless setups. Does anyone have any good sources on what (if anything) controls how hard the fuel pump works?

Reverant

iTrader: (10)

It is mostly standard practice for returnless systems to alter the fuel pressure by adjusting the voltage sent to the fuel pump.

kingofl337

Source: http://www.madracki.com/miata/images/wiring/99sys.pdf
http://www.madracki.com/miata/images/wiring/00sys.pdf

Fuel pump connects to the main relay and then is grounded. It is not adjusted by the ECU.

The firing order and timing is still controlled by the crank mounted sensor. The cam is just a
reset on the megasquirt. So VVT changes shouldn't effect the megasquirt.
Also the megasquirt supports PWM output on Fidle I bet the extra guys could
adapt it to control the VVT.

Someone would have to try to MS a 01 to see if they can get everything to work. If you
leave the MAS in line the VVT should run correctly on the stock computer.

Reverant

iTrader: (10)

Update: The MS and the LM-1 arrived today at work - what a shame I am on a sick leave. :-/
Nevermind, instead of reading my emails tomorrow first thing in the morning, I'll be unwrapping pretty little packages instead. So stay tuned for the first install of an MS on 01+ Miata.

2004GS

iTrader: (1)

I have been told that the stock MAS would not work properly on a turbo charged car, the reason being that its not calibrated for the higher air flow rates you get on a forced induction engine.s THis is the reason we are all using a MAP sensor instead right?

Strange thing is, it seems that all the supercharger kits out there keep the MAS sensor.

Any experience in running a stock MAS on a turbo miata?

Im going to be using the MAP sensor that the MS comes with but if the VVT is using the MAS for something Im worried this will cause further problems for us.

kingofl337

The mazdaspeed turbo uses the same MAS sensor. The reason for using a map sensor is because the ECU wasn't programmed for boost. So once it starts seeing the kinda of vacume a turbo draws the OEM ECU is like "What the hell is going on?" But the megasquirt knows whats up.

Reverant

iTrader: (10)

Got my Megasquirt couple 'o days ago, along with an LM-1 wideband. I still have to order an extension harness, onto which I'll wire up everything. Below is my initial plan, the "ghosted" parts are left under the control of the stock ECU, while the oxygen sensor (pin 23 on the DB37) will be the LM-1 analog output, ignore the heater and gnd wires. My MAP sensor is not onboard, but external in the engine bay, so it is relayed through pins 27, 29 and 31. Just tell me what you guys think.

Aussie Driver

That looks great, but how is the factory ECU going to control the idle if the MS is doing the fuel and spark?

Reverant

iTrader: (10)

Through the idle solenoid, which it still controls. The oem ecu will open/close the solenoid valve and the MS will see the change in manifold pressure and will squirt and spark accordingly.

Arkmage

iTrader: (3)

The crank position sensor will have to remain connected to the stock ECU or you'll get no FIDLE control and a check engine light. Other that that its the finest diagram I have seen yet for MS miatas.

NiklasFalk

iTrader: (1)

Wow, this progress will be interesting to watch (looks like a nobrainer howto in the works ) .

Reverant

iTrader: (10)

No problem there. I have already purchased a used CAS from an NA 1.8, which is the dual wheel, magnetic type. I will retrofit it on the exhaust cam (the slot is still there on NB cars!), so I will actually not use the stock CKP & CMP sensors (which are left totally untouched and will only be connected with the oem ecu).

I have only drawn seperate sensor diagrams for the sake of clarity. Both sensors are integrated in one device, see Randy Stocker's page:

http://members.aol.com/solomiata/Fuel-elec.html

(check at the bottom of the page)

Arkmage

iTrader: (3)

Looks like that miata is in good hands. You are definately on the right track.

Reverant

iTrader: (10)

Just to let you guys know...I've updated the diagram above, I've been studying the connections on the stock ECU so some changes had to be made (ie the ckp and cmp sensors use +12V, not the +5Vref). If you continue to see the old diagram and not the new, just hit the refresh button on your browser.

Jim