Any questions you have before you begin buying, building and installing.
By Jeffer949
#51158
Hello.

I could use some help finding the info I need for what board to use for my upcoming project. Im not new to DIY standalones. I built and installed a few megasquirt systems 15 years ago

I just bought a 1984 maxima and am going to put a l28et motor in it. I just cant find an up to date description as to which boards are best for what kind of build.

Here is list of things I would like it to do.

Batch fire injection
fire 6 individual coils. (LS coils or similar)
Wideband
Boost control
normal sensors, clt, map, tps, Iat
Launch control or flat shift(Not sure if possible on Speeduino and not necessary.)
Fuel pump control

Im not expecting tons of of this I know it has its limits. I just want to start out on the right foot.
Thanks for your help
Attachments
195498954_4212490382141547_3850226252219270367_n.jpg
195498954_4212490382141547_3850226252219270367_n.jpg (73.81 KiB) Viewed 4762 times
User avatar
By Mr_Hypnotic
#51160
Check out the wiki. Tons of good info to get you up to speed.
If it was my project, I would be leaning toward a version 4 board. You could run batch fuel ( 3 channels) and wasted spark (3 channels).
You will need to figure out what is needed for the crank position and other sensors.
It looks like a great project! I can't wait to see the progress! :)
User avatar
By PSIG
#51164
Welcome! There are many board designs, and only a few are described on the Wiki. I would suggest you compile a list of your requirements, and then post for suggestions. For example, batch fire could be 2 channels with 3 injectors each, or 3 channels with 2 each, etc., or your crank position could be VR or digital, and so on. Those are your choices for various reasons, not ours, but directly affect which boards you could use.

While your'e at it, you will also need a list of goals, to give focus for reaching them and to help us with the general directions you are going. Are you making your own wiring harness or modding the original? Is this first install permanent? Stuff like that. If you're not sure, just say so. The configuration and board used for a land speed record may be different than a daily driver looking for max economy or weekend auto-x.
By GabeZ
#51195
Is your 84 maxima an efi L28? Does it have an optical (360 slot) distributor? Or is it a diesel maxima you are converting to L28?

An aftermarket AEM 24/1 optical disk can be used in the L28 optical distributors. They are available in 2 different diameters and can be fit to most Nissan optical 360 distributors/cas. You would use this as a 12 tooth crank/1 tooth cam in dual wheel mode. Diyautotune makes a similar disk but I found the AEM to be much higher quality.

The Nissan optical distributor with a 24/1 interfaces easily with the speeduino. You do not need a VR conditioner, simply use the internal pullups and be sure to trigger on the falling edges

If you are using an oem Nissan harness you may need to reconfigure main relay so that it turns on with key. This involves grounding the solenoid at the ecu harness connection, and making sure the positive is switched with key. These seem to be wired differently Pre-86, and may already have positive for main relay switched with key, in which case you still need to ground the main relay at ecu harness location (Nissan ecu "eccs" controls ground for its own main power relay).

Also you would want to introduce a relay for the injector 12v+, on many Nissan they are wired directly to battery via fusible link.

I would recommend any 4channel fuel/ign speeduino. You would only be using 3 injector outputs, and 1-3 ignition outputs depending on whether or not your using distributor or wasted spark. So a v0.3, v0.4, or UA4C would all work great it just comes down to how you want to make your enclosure and interface to your OEM connection (or make your own harness).
By GabeZ
#51196
Also, GM temp sensors are the easiest option. A GM 14mm straight thread coolant sensor will thread into Nissan location. and has a much better sealed connection.
By Jeffer949
#51549
GabeZ wrote: Sat Jun 19, 2021 7:56 am Is your 84 maxima an efi L28? Does it have an optical (360 slot) distributor? Or is it a diesel maxima you are converting to L28?

An aftermarket AEM 24/1 optical disk can be used in the L28 optical distributors. They are available in 2 different diameters and can be fit to most Nissan optical 360 distributors/cas. You would use this as a 12 tooth crank/1 tooth cam in dual wheel mode. Diyautotune makes a similar disk but I found the AEM to be much higher quality.

The Nissan optical distributor with a 24/1 interfaces easily with the speeduino. You do not need a VR conditioner, simply use the internal pullups and be sure to trigger on the falling edges

If you are using an oem Nissan harness you may need to reconfigure main relay so that it turns on with key. This involves grounding the solenoid at the ecu harness connection, and making sure the positive is switched with key. These seem to be wired differently Pre-86, and may already have positive for main relay switched with key, in which case you still need to ground the main relay at ecu harness location (Nissan ecu "eccs" controls ground for its own main power relay).

Also you would want to introduce a relay for the injector 12v+, on many Nissan they are wired directly to battery via fusible link.

I would recommend any 4channel fuel/ign speeduino. You would only be using 3 injector outputs, and 1-3 ignition outputs depending on whether or not your using distributor or wasted spark. So a v0.3, v0.4, or UA4C would all work great it just comes down to how you want to make your enclosure and interface to your OEM connection (or make your own harness).
Thanks for the reply GabeZ. Are you on Hybridz also? Your user name seems familiar. Sorry about the late reply. Just got back from family vacation in Yellowstone.

This has the L24E engine in it. I actually dont have the car yet. The guy selling it is holding it for me till this weekend as I was leaving for vacation right after I found the car. I believe it has the same EFI system as the 280zx did. I will more than likely try to find a 280zx turbo distributor but If I cant I will make a holder for a sensor using the stock Oil pump shaft as a turbo oil pump shaft will be hard to find.

Thanks for the heads up on the AEM wheel. I think back in the day we used the 280zx distributor with a z31 trigger wheel if I remember correctly.

Getting the harness to work with new or with the factory one is not a big issue. I will say that If I can get away from screw terminal like megasquirt has I will gladly go that route.

On the ignition side I would like to run 6 coils. I have a File around here somewhere to have a bracket cut for ls1 type coils. So I would like to go that route rather than wasted spark. Granted it is based on I like how it looks.

So based on this. Which board should I Go with. Ill be honest I want to get it ordered before anything else happens with vendors getting shut down by the EPA.
By GabeZ
#51586
You will need to run the ls1 coils in a wasted spark configuration, as far as I know speeduino does not yet support 6 individual ignition outputs.

You would still have 6 individual coils, but they would be paired in the wiring.

If your going with the coil packs and can't find a turbo distributor, you can use an 86-89 D21 Z24i distributor without the cap and rotor. The oil pump shaft will fit the l series. This will give you the optical sensor that you could install the 24/1 disk.

A 90-95 D21 or 89-90 240sx ka24e distributor and shaft would also work, but the mounting ears are slightly different compared to the L/Z series. The oil pump shaft and most dimensions are compatible.

The screw terminals of the v0.3 do not need to be used, you can leave them off and solder wires directly to board.
By theonewithin
#51592
Speeduino is capable of 8x8 operation using a STM32 or Teensy 3.5.

Even the Mega 2560 can do 9 total timed outputs (3x6) so you could add an additional driver circuit and tweak the firmware if you really wanted to.

Search the forum for details.
User avatar
By Rdgordon
#52209
Hi, I get a feeling we may end up having a few discussions about your project! I've got an 82 280zx, that I'm putting a 280zx turbo motor in, and a lot like you, want to try building an ECU, instead of paying $2k+ for something a million times easier!

I've got a lot of experience in electronics, and automotive, but car stereos was where my mixing of the two always ended.

Anyways, hope to catch you around so we can trade stories! I'm just starting the research into an ECU, which at present I'm planning to run as a secondary ECU, just monitoring sensors and what not, then roll into doing coil on plug and injector control when I feel confident I've made something stable.

Best of luck! Your maxima sounds like an incredible project!

Robin.
By Jeffer949
#52389
Hello this actually isnt my first turbo l series. I used to have a 1974 260z 5hat I swapped in a l28et into it. Ran megasquirt1 on it. Was running a holset he351cw pushing 20 psi. 750cc injectors intercooler etc. Zg fender flairs and mirrors. Roughly 400 hp.

My advice for you... just ditch the stock ecu and sell it on ebay. Once you have it hooked up there is no reason not to use it.

You dont have an extra turbo manifold do you? I cant find one. I've sold close to 10 over the years.

you could set 'skip revolutions' to 3, then it wou[…]

Hi, I am trying to assign Signed values to the x-a[…]

blitzbox

I've finally figured out why MAP and Lambda weren'[…]

Hello, I bring news!! Let me tell you that after […]

Still can't find what you're looking for?