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My Megasquirt plans check and feedback pls.

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Old 05-01-2012, 04:24 PM
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Default My Megasquirt plans check and feedback pls.

This weekend I should get my '99 back from the shop with a new (to the car) block from a '97. That of course means lower compression than my stock '99 block and lower compression means I can boost more

I'm planning on going MS3. Please let me know where I'm being stupid....

Goals:
  • Streetable (my wife should be able to drive)
  • Light track use (would probably drop boost to make blowing up less likely)
  • 240 - 270 rwhp (14psi)
  • MS (even if that's not strictly necessary, I just want to!)

Current Setup:
  • '99 NB, no AC, Manual
  • FM2 kit from 2000 with link (added later), this includes:
  • -> internal MAP sensor
  • -> Boost control solenoid
  • -> 2 additional injectors for boost enrichment driven by the link installed BEFORE the intake manifold (yikes!)
  • FM big clutch kit
  • FM Cat-back exhaust
  • Wilwood brakes
  • Has been running successfully at up to 14psi and high octane gas until the engine blew up

MS Plans:
  • Keep original ECU for passing Emissions OBDII inspection
  • Run spark, boost and fuel ONLY off MS for now
  • [S]Batch fuel is OK for now[/SGoing MS3X and sequential fuel.
  • Drive approx 500cc High-Z injectors from MS
  • Drive high current Chevy coils (2 of them) in wasted spark config from MS
  • Run 4 LS2 coils off the MS3X
  • Get JimStimX kit to check the MS thoroughly before install

Later upgrade thoughts:
What I have:
  • All kindsa tools, including basic electronic tools like soldering equipment, voltmeter, power supplies etc.
  • Standard electronic components (heatshrink, heatsinks, resistors, transistors, diodes...)
  • SD card for logging
  • USB cable
  • Laptop
  • Home furnace diagnostic analyzer - maybe the thermocouple can go high enough for EGT measurements
  • Instructions for wasted spark direct drive (http://www.mye28.com/viewtopic.php?t=68448)
  • '99 Miata
  • waaaaay too small garage

This is what my research indicates I need:
  • LC1 wideband sensor (already ordered)
  • PCB V3.0 with MS3 is sufficient without the and MS3X
  • Mapdaddy MAP sensor
  • Boost control mod
  • 2x coil driver mod kit (will probably have to make up a secondary board for those)
  • MS wiring bundle 23" long
  • All kinds of Miata connectors for boomslang
  • coils, spark wires and mounting HW
  • Injectors

Questions:
  • Boomslang install would be the best/cleanest way to go for this, assuming I want to keep stock ECU - correct?
  • Are the connectors neeeded to boomslang the '99 the same as needed for '96 - '97?
  • MS3 should be sufficient for this, no MS3X needed for now - correct?
  • Does the '99 have a stock knock sensor or not? (FM indicates the link for the '99 came with a knock sensor, but the service manual lists error codes for the knock sensor)
  • '99 tach signal comes from ECU, so I should not have to worry about that at least - correct?
  • I can't have the CEL coming on, or I will fail OBDII emissions. Do I need to do something to cheat the stock ECU in terms of O2 signal or such?
  • Can I delete the AFM without CEL coming on?

That puts me at just around $550 $600 to DIYautotune right now. I'm almost ready to hit that 'checkout' button on their website, but would really
like to make sure I got this right and I don't have to place another 20 small orders- or, even worse, big ones!

Last edited by stefanst; 05-02-2012 at 09:22 AM.
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Old 05-01-2012, 04:50 PM
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Has been running successfully at up to 14psi and high octane gas until the engine blew up
Made me laugh.

it looks like a lot of work to get OBDII functionality. How often are your emissions that you need to do all this hoopla? Why not run standalone and just swap to stock ECU once a year?

And to answer some of your questions - deleting MAF and replacing the O2 sensor would require a "magic box" to fool the stock ECU. You could get away with running both stock O2 sensors and then add another bung for a wideband.
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Old 05-01-2012, 05:03 PM
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Originally Posted by soviet
Made me laugh.
Made me cry when it happened

But it was running at that level for 50,000 miles! And then it blew up....

Emissions check is once per year, but I would also have to pull/replace injectors, disable the turbo and probably a few more things....
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Old 05-01-2012, 05:38 PM
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I highly suggest getting the expander board now and starting with the MS3x. Start with sequential fuel. Your car is already wired for it and it is easy to set up. Absolutely no reason to run fuel in batch. then I would suggest get 4 LS2 coils and running them in wasted spark if you really want to avoid running 2 additional wires now. LS2 coils go for about $25 a piece new online all day long. So no reason to get any other coils.
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Old 05-01-2012, 06:10 PM
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Originally Posted by shuiend
then I would suggest get 4 LS2 coils and running them in wasted spark if you really want to avoid running 2 additional wires now. LS2 coils go for about $25 a piece new online all day long. So no reason to get any other coils.
OK- point taken. Looks like LS2 coils often sell in batches of 8 - anyone need the other 4?

I'll update my original post to reflect the changes.
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Old 05-02-2012, 02:08 AM
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Originally Posted by soviet
And to answer some of your questions - deleting MAF and replacing the O2 sensor would require a "magic box" to fool the stock ECU. You could get away with running both stock O2 sensors and then add another bung for a wideband.
The LC1 should be able to output wideband on one analog channel and narrowband simulation on the other.

Boomslang install would be the best/cleanest way to go for this - correct?
Cleanest? Swap ECUs once a year and wire your wastegate open. If you don't want to swap ECUs and need to stay emissions "legal" then yes.

Are the connectors neeeded to boomslang the '99 the same as needed for '96 - '97?
ECU connectors? yes.

MS3 should be sufficient for this, no MS3X needed for now - correct?
Not needed but you should do it, makes the MS3 build incredibly easier and lets you go full sequential as well as giving you more inputs/outputs than you will know what to do with.

Does the '99 have a stock knock sensor or not? (FM indicates the link for the '99 came with a knock sensor, but the service manual lists error codes for the knock sensor)
Yes, Megasquirt doesn't have anything that works in practice to do anything with a Knock signal. There is some stuff for MS3 on the horizon that will have meaningful knock detection.

`99 tach signal comes from ECU, so I should not have to worry about that at least - correct?
Correct, should get the tach signal from the factory ECU.


I can't have the CEL coming on, or I will fail OBDII emissions. Do I need to do something to cheat the stock ECU in terms of O2 signal or such?
Set the 2nd LC1 analog output to narrowband, send it to the OEM ECU.


Can I delete the AFM without CEL coming on?
No. Every stock sensor will have to remain on the car wired to the OEM ECU.
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Old 05-02-2012, 10:08 AM
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Since our MD member, Soviet, posted he had Antique tags on his Miata, I checked to see what the PA rules are on that. Looks like in PA you can register a 'classic' after only 15 years. Since mine is a '99, it seems that in two years I can get a classic registration for it. And that means <drumroll please> NO f-ing emissions!
So if I get emissions done now in 2012, then I'll have to do them again in 2013 and that's that!
All that being said, this means that I could go standalone and only have to swap back original ECU and injectors once until eternity. That may definitely be quite doable. So now I need to look into what it takes to go standalone.

This forum is definitely a host of inspiration!
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Old 05-02-2012, 10:13 AM
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who cares about emissions? so one week out of a year you have to wire open the wastegate and put stock injectors and the MAF back on.

there's other rules that go with antique plates beyond the benefits.
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Old 05-02-2012, 10:31 AM
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Originally Posted by Braineack
there's other rules that go with antique plates beyond the benefits.
On classic cars in PA it's apparently no daily driving, but that's it. And the price for insurance goes down, no inspection, no registration fees.
Since I won't be driving daily, that shouldn't be too much of a deterrent for me!

I'm really feeling the peer-pressure here to go standalone
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Old 05-02-2012, 10:35 AM
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there's little reason not to. does PA have annual emissions? when's your next test due?


i know in VA antique plates limit car use to:

•Participation in antique car club activities, exhibits, tours, parades, and similar events.

•Testing its operation, obtaining repairs or maintenance, selling the vehicle or trailer, transportation to and from events as described in number 1 above and for the occasional pleasure driving not to exceed 250 miles from your residence.

•Carrying or transporting passengers, personal effects or other antique motor vehicles being transported for show purposes.



I doubt any cop would question me on it, but it's silly--especially since I'm odbI and can pass emissions
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Old 05-02-2012, 11:11 AM
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OK,

I'm almost convinced to go standalone with an MS3X. If I'm going to get classic tags or not in two years time remains to be seen.

For standalone the following additional requirements seem to apply:
  • MS generate tach output, so I need to build the tach circuit
  • MS needs to deal with the idle, but MS3X shouldn't have a huge problem there
  • MS needs to control fans - so I need a high-power FET, driving a relay. Shouldn't be too bad
  • .....

To go back to stock for testing I would have to:
  • Plug stock ECU back into harness
  • Replace LS2 coils with stock coils
  • Replace ignition wiring
  • Re-install AFM
  • Swap injectors for original
  • Wire open WG

Anything else?
Could the stock ECU possibly drive the LS2 coils, so I don't have to undo my ignition mods?
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Old 05-02-2012, 11:57 AM
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expander card has tachout circuit already onboard.
ms3x idle is baller city, better than stock. built into expander
fan control is simple and easy, already built into expander

building an ms3x is simple, the expander make it easy as ever. it's just building the hanress that becomes the pain, but even that's not too hard, just time consuming.
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Old 05-03-2012, 11:25 PM
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OK - there's only one thing left I think I didn't have in my original plans: IAT sensor. What does that figure under: Nice toy, Good to have, Very good to have or MUST have or the car won't run properly?
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Old 05-03-2012, 11:30 PM
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Originally Posted by stefanst
OK - there's only one thing left I think I didn't have in my original plans: IAT sensor. What does that figure under: Nice toy, Good to have, Very good to have or MUST have or the car won't run properly?
Must have.

Edit, I see you are keeping the stock MAF in place, but I'd still wire in a separate GM IAT sensor.

--Ferdi
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Old 05-03-2012, 11:42 PM
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Originally Posted by ftjandra
Must have.

Edit, I see you are keeping the stock MAF in place, but I'd still wire in a separate GM IAT sensor.

--Ferdi
Aaaah. About the stock MAF. It's going out most likely since I'm planning on going standalone and getting the engine back to stock once per year to pass emissions. And it looks like an IAT is lighter than an MAF.

So a GM IAT. The spending just never ends!
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Old 05-04-2012, 10:11 AM
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I mean to could do something crazy and cut the stock AIT sensor out of the MAF and epoxy it into a charge pipe for free
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Old 05-04-2012, 10:29 AM
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He has a 99, isn't the stock ait sensor just kind of plugged into intake pipe already? I do not think it is attached to the maf.
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Old 05-04-2012, 10:33 AM
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ohhh yeah it is.
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Old 05-04-2012, 10:33 AM
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Originally Posted by Braineack
I mean to could do something crazy and cut the stock AIT sensor out of the MAF and epoxy it into a charge pipe for free
I got some bailing wire and an old infrared fever thermometer. I'm sure I can duct-tape something up
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Old 05-04-2012, 10:36 AM
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Originally Posted by shuiend
He has a 99, isn't the stock ait sensor just kind of plugged into intake pipe already? I do not think it is attached to the maf.
At some point I'll visit my car and identify the location and connections of all sensors. Maybe then I won't have to ask all those really smart questions
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