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- MEGAsquirt (https://www.miataturbo.net/megasquirt-18/)

- - Racepak IQ3s How-To (https://www.miataturbo.net/megasquirt-18/racepak-iq3s-how-91964/)

Racepak IQ3s How-To

This write-up will have 2 parts. How to create your own custom channels to read more than the basic fields that are supported out of the box, and how to install it in an NA.

Part 1:

The Racepak IQ3s has Megasquirt 3 "support" right out of the box. But not what I wanted.

https://cimg2.ibsrv.net/gimg/www.mia...dc1a38f607.png

The default config has 20 predefined channels, and while those may be enough for some I wanted to do more. If you just want to use the 20 pre-defined channels then the setup is very straight forward and there are other writeups to look at.
This write-up will cover what I can't find documented anywhere, how to use the User Defined ECU setting.

This document will be needed: http://www.msextra.com/doc/pdf/Megas..._Broadcast.pdf

If you skip down to Section 2 you will see the giant list of fields that can be transmitted outside the basic dash broadcasting. You get to pick 20 total of these.

Setting up your Megasquirt

First step is turning on the broadcast fields you need. We need to go to CAN-bus/Testmodes-->CAN Realtime Data Broadcasting, and turn on the master enable. Keep the Base message identifier at 1520 unless you have a reason to change it.

Then just enable what you want transmitted. I chose 50Hz because why not. You may also need to open the other CAN Realtime Data Broadcasting menus to get more fields.

https://cimg3.ibsrv.net/gimg/www.mia...eb41add905.png

Once you Burn that you are done with the megasquirt side.

Setting up the Racepak

This took a decent amount of trial and error, and I will probably update it as I learn more.

To start you need to setup your IQ3s to use the User Defined ECU mode. So Right click on IQ3 Street and go to the Dash Info Tab. Select the ECU Type Field and change it to User Configured

https://cimg4.ibsrv.net/gimg/www.mia...91d51c373b.png

Then Send that configuration and close the Menu.

Next go to Edit->Read VNet Config (new channels), you will get a single channel titled EFI Setup. Right click on that and set the number of channels to 20 (or less if you don't need 20), the CAN Bus Bit Rate to 500k and the CAN Bus Termination Resistor to On

https://cimg9.ibsrv.net/gimg/www.mia...852f2fd7fc.png

Send that configuration, and then Read V-Net channels again. You should now have 20 ECU channels to define however you want.

Defining ECU channels

This part took the most trial and error, and will be the most confusing to document. I think the best way to explain it is to just walk through an example. We will start with Coolant temp.

Right click on one of the ECU Channels and take a look at the parameters. Change the Name to whatever you want.

The Channel Options are the important part

Logger Sample Rate: Rate at which the IQ3 will capture the channel
CAN ID For message on the network: This is the base identifier (default was 1520) + group number. So 1522 for coolant temp
CAN ID Message Type: Keep this 11-Bit Standard
Byte Order: Megasquirt uses Big-Endian, so change that
Message Index Bye Location: None
Message Index byte value: Dont change
Message Data Byte containing low byte of data: This will be offset in group + 1. So 7 for coolant temp
Bit offset into first byte of data: 0
Data Type: This is based off the sign? column. So for Coolant temp its "Signed"
Number of bits in data received: This is Size * 8. So 16 for coolant temp.

Next look in the upper corner for the Linear conversion.

Leave Raw Data Value A alone (unless you have a reason to change it)
Raw Data value B: Look at the Multiply/Divide columns. For coolant temp Divide is 10. So data Value B of 10 will become 1.
Set the min/max and decimal points to whatever you want to display, and set the unit.

Send the configuration and you have now defined a channel.

https://cimg3.ibsrv.net/gimg/www.mia...7d9884627f.png

So did you like, sleep AT ALL last night? :laugh:

Actually didn't take long once I figured out the custom channels. Around 10pm I had to make the decision to stay up all night and get it wired in, or just do it today. Sadly I chose to do it today, so that write-up will come later.

I hate you. This thread is going to cost me money. :giggle:

Nice writeup. Can you use the NB speed sensor 'as is' and just run the wires if on an NA? (IQ3 manual Pg 31). And 'gear selection indicator' is basically speed vs rpm calibration?

Quote:

Originally Posted by bahurd (Post 1388513)

Nice writeup. Can you use the NB speed sensor 'as is' and just run the wires if on an NA? (IQ3 manual Pg 31). And 'gear selection indicator' is basically speed vs rpm calibration?

Yes and yes. Make sure you use the Variable Reluctance setting.

Another small update I forgot to post here.

There is a bug with any IQ3 Street firmware greater than 2.13. You get "noisy" values, and random flashes of garbage values. Racepak sent me older firmware, and everything up to 2.13 worked fine. After that you get issues.

Still need to do the writeup for wiring for an NA. Coming soon.

I don't want to FU the thread but I've got a question related to odometer. Some states [mine] have dim views on odometer "tampering" (my quotes because it's not really tampering). If you were to sell the car say, that otherwise would have a clear blemish free title, do you just now acknowledge on the title the mileage is incorrect/unknown?

Quote:

Originally Posted by bahurd (Post 1390316)

At least in SC there is a checkbox on the title you check if the mileage might be wrong. I bought a miata where the speedo cable became slightly unplugged and the guy did not know how easy it was to fix. So he just left it like that and drove for a while, then the HG blew and the car sat and I bought it. Now I am getting it ready to sell.

Quote:

Originally Posted by shuiend (Post 1390319)

More or less the same here. I guess we wouldn't be selling to the typical M.net crowd anyway where everything needs to be 'correct'.

Set up the IQ3 odometer. Then when you want to sell spin the speedo with a drill until the mileage matches up. :D

Disclaimer: do not do this. It's illegal

Quote:

Originally Posted by aidandj (Post 1390322)

Set up the IQ3 odometer. Then when you want to sell spin the speedo with a drill until the mileage matches up. :D

$1000 + felony + likely jail time in this state. Not worth it on a Miata... :nono:

Back to the regularly scheduled thread...

Very interesting, thanks! I have a Dash 2 w/ CAN in my Exocet that I am going to need to program, so this at least gets me part way there for the MS side of things.

And all of my videos so far.

@aidandj first class job! :likecat::likecat::likecat:

Threads like this make me realize how dumb I am. Thanks