Saturday, June 03, 2006 - 11:24 am, by: Hudson Thomas(Hudson)
Anyone else fitted the SMT6 to their V8 yet and had it tuned? What is the consensus (if any) on these units?
A friend of mine has one but won't fit it until he he has an accurate wiring diagram (the one shown on the first page of this thread is said to be partly incorrect). I note Peter T's webpage is not working (he said he would make available a high quality version of the diagram on this page).
Thursday, June 08, 2006 - 06:26 am, by: Anish Varsani(Yomama)
Try attaching the unit to the stock ECU with double sided tape. Run an earth directly from the battery. If you can, run a positive through a fuse to the unit and use a relay from the ECU positive to turn the relay on to supply the SMT6.
This way you'll have a clean power supply and the stock ecu casing should be earth to the chasis so it'll help noise rejection.
PM me if you want the relay diagram drawn up. I'll hand draw it and scan it.
Thursday, June 08, 2006 - 08:46 am, by: Damien Smith(Damien)
Mine would turn over a few times before starting so I asked Perfect Power and they said that the crank signal can be weak when starting and the SMT6 has difficulty picking up the signal.
They said to use a relay and use the RPM switch at 600RPM so that when starting the crank signal bypasses the SMT and goes direct to the ECU then over 600RPM when the engine is running it routes through the SMT. Here's a wiring diagram I put together.
Thursday, June 08, 2006 - 04:52 pm, by: Anish Varsani(Yomama)
Damien, does this setup work if you wire the pullup to the crank input to the SMT6? During starting, you'll end up with the pullup and the ECU's internal pullup in circuit.
Friday, June 09, 2006 - 05:47 pm, by: Anish Varsani(Yomama)
Damien, I tried the relay and it didn't work.
However, I've just wired up the SMT6 without the pullup and set the pick up level to low level input and the car starts fine. Now if the revs drop below 600rpm, the car shouldn't stall and you shouldn't have any starting problems.
Friday, June 09, 2006 - 06:57 pm, by: Anish Varsani(Yomama)
Ok, my bad. That fixes up the ignition problem but the air flow meter won't work because there is a DC offset on the AFM of about 0.5V. I've emailed Perfect Power to see if there's a firmware update that will change the low level pick up from 0.1V to 0.5V or a bit higher. OR drop the high level pickup from 4V down to 1V.
Saturday, June 10, 2006 - 10:43 pm, by: Anish Varsani(Yomama)
Was having another fiddle today. Looks like the SMT can't do ignition and fuel trim stably. Low level pickup is needed to make sure the car starts and dosnt' stall when revs drop below 600rpm. AFM signal can't be read because it only drops down to about 0.4V instead of below 0.1V for the low level pickup.
If only a fuel trim is required, then it'd be ok. Just tee into the crank signal for RPM to the SMT6 or it can be used for timing. With all of the cheap SAFC's around it might be worth using the SMT for timing and monitoring AFR while using an SAFC for fuel trim.
If RPM can be maintained above about 700rpm, I think the unit will be ok for fuel and timing as the crank signal amplitude is a little higher. I'll see how my car idles after putting on the blower. The IAC motor isn't used with the M90 kit so Idle may be adjustable to some degree with an air bypass if needed.
Sunday, June 11, 2006 - 10:33 pm, by: Anish Varsani(Yomama)
There's a way to pull the AFM signal down to 0V by using a zenner diode and a resistor. I seems to work so far. Will go for a dirve tomorow and make sure all is fine. The air flow mod is definately working since if I change the idle cell from 6 to 100, the car surges and then stalls.
Wednesday, June 14, 2006 - 09:40 am, by: Anish Varsani(Yomama)
This works. Wired it in on Saturday night and haven't had a problem since.
If V8 owners go back a few pages, my fuel map and ignition map have been posted up. There's '6' in one of the cells that corresponds to closed throttle idle. This setting contributes greatly to off the mark response. Even after two days of driving, the ECU dosn't seem to have cut this value back. Anyone getting a tune might want to ask the tuner to have a play around in the closed loop areas of the map. There's a feature in the SMT6 settings to make divide all fuel adjustments by 4. Using this might allow small changes without the stock ecu cutting fuel out of the map.
Note that this feature will only work if your WOT column has a modification of less than +-32 when not dividing by 4.
If anyone in the Brisbane/Gold Coast area want a hand, PM me and I'll get back to you when I come back from leave.
Wednesday, June 14, 2006 - 10:36 am, by: Anish Varsani(Yomama)
Will have to do that from home. Havn't go the map file or SMT software at work.
I'll just post up the whole map file, use map settings at your own risk. The global settings will be in there.
Off the top of my head: Mode: 10 Teeth per turn: 12 Teeth per firing: 3 Low level pickup: On Input polarity: see below Output polarity: see below
This will be enough for you to be able to start your engine. The input/output polarity effects the stability of the timing modification. You need to set it to the opposite of what ever the default is. If you look at it on a oscilloscope, these settings will give you the most stable ignition pulse to the stock ECU.
Damien, I noticed you're using a Map ECU. Are you going to use the SMT6 for fuel mod and timing or just for timing? If it's only for timing, you don't need to use the diode and resistor for the AFM. You won't have to run the AFM signal into the SMT6 at all. The rest of the wiring and settings will be the same.
Wednesday, June 14, 2006 - 11:00 am, by: Damien Smith(Damien)
I'll just be using it for timing but I want to put all the details on my website for reference.
Regarding the input/output polarity, how do you know if it's triggering on the positive or negative edge by default? Should they be set to both positive or both negative?
Wednesday, June 14, 2006 - 11:31 am, by: Lew Radbourn(Marlew)
F&&#* me i recon i will leave it up to you guys to sort this out Anish . mate when ya recon it is all sorted i will give you a call mate this is just getting to be like walking through a mine field. Damien sounds good that idea of placing all the info on your site.
Wednesday, June 14, 2006 - 01:06 pm, by: Anish Varsani(Yomama)
Damien, if you go to global settings, I think it's the last tab.
They should both be the same. Whatever is the oposite of the default. I'll let you know with some screen shots and the map file when I get home.
Lew, it's pretty straight foward. The perfect power support is not the best, that's why it's take a while to sort out. I ended up having to go on hunches as perfect power wouldn't supply me with specific details on how the unit works and what hardware is inside.
As a side note, bullet sell these as a piggyback with their blower kits. The idle speed might be higher with the blower kit bolted on so they may not have experienced any problems.
Wednesday, June 14, 2006 - 01:20 pm, by: Damien Smith(Damien)
I misunderstood about the polarity sorry. Default setting in the software is "On" so they should both be switched "Off" which is what Peter Taplin posted initially.
Interesting that Bullet use is as a piggyback. I wonder how they adjust the closed loop tuning when on boost? Considering the stock ECU holds onto closed loop almost until WOT, the AFR would be around 14:1 when it would be better at 12.5:1 when on boost at part throttle.
I've looked at the closed loop tuning capability of the SMT6 but because it only has 1 analog table you can only use it to tune closed loop OR alter the MAF signal but not both. There is provision for an extra injector of course but that's getting a bit messy.
Previous
