Toyota Celica Supra Forum banner

5MGTE Guide with Microsquirt

34555 Views 57 Replies 23 Participants Last post by  Slidymk2
This is for the people who are looking to turbo their 5m-ge engine. This will sort of be a how to or at least how I did it. I had a turbo setup with a RRFPR and it never really ran well at all so I changed just about everything.
It is a pretty cheap setup in terms of cost but it is a full standalone setup. It was a pretty easy and straight forward install. Easier than even a PNP AEM on a 7mgte because of the multiplex crap that never seems to work right.

How it runs after 30 mins of basic tuning
Still needs a lot more tuning but it runs ok and boosts fine

Factory Service Repair Manual(TSRM) For the 85/86 supra

Main parts
Late year 5mge early years will work fine as well but you will need some of the later year parts
4 wire stock TPS Make sure the TPS works. Mine did not work so I pulled all apart and it seems like the ceramic solder points dont hold and it loses connection inside.
Stock coolant temp sensor
Stock ignition setup with stock VR pickups(2 of them)
$30~ GM 3 Bar map sensor
$20~ GM IAT(Any IAT should work I use a buick GNX)
$210+ 750cc high impedance injectors bosch style
$120~ Walbro 450 in tank pump
Stock fuel lines/rail/FPR
$360~ ECU is a Microsquirt V3 with the 8 foot harness yes Microsquirt
CT26 with 7mgte exhaust manifold
$50-$150~ Oil feed and return lines soft line kit works the best(rabidchimp, arizona performance, drift motion, ebay ect)
Return bung welded oil pan
$50-$350~ 2.5 inch IC pipes with matching IC diameter(can be same side exit or normal or even stock 7mgte stuff)
IAC removed and blocked on intake
EGR blocked on intake manifold and head/exhaust side
$125~ Wideband O2 sensor I use the LC-1 but a cheaper one is the Spartan V2 from 14point7 which should be fine
Downpipe with O2 bung
Turbo to airfilter pipe(accordion pipe)
Colder spark plugs I used NGK BRP8ES

This runs $1100~ plus whatever it costs you for the parts that dont have prices next to them.

Recommend/optional parts
Oil filter relocation kit(cant replace filter without pulling turbo without this)
Stronger clutch if running more than 5psi or sticky tires mine was new and slips
Bigger radiator with electric fans( I use a MKIII aluminium one off ebay)

Microsquirt ECU is basically Megasquirt V2 with some unique features and some missing features
The V3 version is important here because it has dual spark. Update to firmware version to MS2/Extra 3.3.3
It does not have stepper motor controll so it cant run the stock IAC but if you want an IAC you can get a PWM valve.

Fuel setup
Drop the tank and install the walbro fuel pump in the stock pickup
Install the injectors into the stock fuel rail.
Replace the fuel filter

You can run any size injector you want I just chose the 750cc because I plan to run e85 at 15psi of boost
Just make sure whatever injector you run is high impedance OR you have resistors installed inline as the ECU cant run more than 2 if low impedance.
Also check your injectors before you install them one of mine was stuck wide open and flowed full flow of gas directly into the intake manifold filling nearly
the entire engine with fuel
Fuel injector wiring makes this batch injection the microsquirt does not have enough outputs to run sequential injection
The injectors and ECU need to run off the same 12v relay
You should solder and heatwrap all connection you make if possible
The stock fuel pump relay is triggered off a wire that normally runs off the stock AFM
You can wire this as shown in the images to have it run off key on

Begin by removing the entire stock engine harness and ECU. The harness will pull through the firewall without needing to cut anything off.
Cut the TPS and coolant sensor connectors off you will be reusing them.
Wire using the diagram below and the microsquirt website here
All of the wires on the harness that comes with the ECU is labeled
You need a switched 12v power supply from a relay for the ECU and injectors

Turbo/charge piping
Trim the exhaust manifold to clear the power steering bracket a grinder worked for me.
Pull the oil pan and get a bung welded to it. I suggest a -10 AN bung for the drain.
The block has a oil port on it which is BSP thread use that for the feed. You can buy BSP to -4 AN if you are using AN
Double check the wastegate is working and install the turbo make sure you have gaskets where needed.
Routing the intercooler pipes can be a pain and is up to you how you want them routed.
I suggest using T-bolt clamps for everything if you can
The charge piping needs to flex a bit as the engine moves side to side under loads.
Install the downpipe I would not recomend a stock MKIII one
You can get a nice elbow and get a downpipe/exhaust made at a shop for pretty cheap as well.

Also if looking for parts on Rockauto
Look under celica then select 2.8l engine
Way more selection compared to selecting supra on the list
This is the best way to buy OEM type chassis parts like bushing that I have found.

Wiring diagrams

Tune setup
Calibrate your TPS
Setup for your wideband and map you are using in the settings
Input the general settings and the basic tune settings.
ECU needs power when you burn the settings to it.
Also needs a reset(power off and back on) for some settings after you burn them.

Most important part to get your timing correct
On the ignition options menu the tooth angle will need to be adjusted
For example on my setup I had to set the dizzy a tooth retarded to get it to zero out base timing
It might need to be 0 degrees or 30 degrees on your setup for the tooth angle number 1 setting
To set this correctly you need to set the fixed advance option to Fixed Timing
Using a timing light on the crank while the car is running, adjust the tooth #1 angle to get the timing to match exactly timing for fixed advance setting
I used 0 for the fixed advance setting and had to set the tooth #1 angle to 9 degrees
If it does not match going down to 0 on the setting you might need to retard or advance the distributor or even jump a tooth on it.

My car would start on rising edge setting but it would lose sync all the time at higher RPM
Falling edge cured that but it changes the timing by around 22 degrees
It is very important to make sure the ECU sees exactly the same timing as the engine is running at

This is a rough tune I made using some of the other tunes posted on here for the 7mgte like williamb82's tune in the megasquirt thread
I have driven this tune approximately 50 miles. Its a pretty safe tune I feel, AFRs run low 11s to low 10s at high rpm on boost
Max boost I have seen is about 145KPA on this setup which is around 6.5 psi I will be adjusting the tune and boosting a lot later on.
You can tune and adjust settings while driving you dont need to reset the ECU for every adjustment
ECU will show 1 sync loss every time you burn the ECU if engine is running.

Direct Link to the MSQ tune
right click save as
Make sure the file ends in .msq
not .txt

Main forum for the MSEXTRA if you have issues with the software or anything else with the microsquirt

Anyone else who has a turbo 5 or 6m or 7m feel free to add some advise on the tune

1/4 times on this setup here
See less See more
1 - 1 of 58 Posts
great write up. i may have missed it, but what did you do or calculations did you run to figure out the base ignition table? Also, why microsquirt instead of the full ms2/ms3? I look forward to your response
1 - 1 of 58 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.