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Beams 3SGE + G4+ Xtreme 1983 Toyota Carina

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probably the best source of information for wiring etc for beams engines is on this site:


Take a look through some of the threads there, there are ECU pinouts and so on.
I probably wont be able to help you too much more specifically from there. 

But there are very few wires actually needed hooked up to get the motor running.

If you're not too sure, it would be best to get an auto electrician to wire up some of the basics for you.

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Hey David, Just read through this thread, I admire your incremental approach to tuning your car. I'll take away the use of dropbox for managing logs from the comfort of my arm chair when my project is running. 

Keep the updates coming :) 

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I've been tinkering with a few other things, however for the better part, the car is now running great. 

I am going to enter a series here called "Superlap" which is a time attack sort of contest that goes around to a few different tracks around the country.

One of them is based in Cromwell, which is a 21 hour trip each way for me:


Which is where cruise control just really shines! This is one of my favourite features so far, and one that I wasnt expecting to be available when I initially purchased the ECU. (I didnt have E-throttle initially either)

I setup an injector test bench and used the advanced injector test function to work out accurate deadtimes and short pulsewdith adder tables for both sets of my injectors:


Which made the staged injection work much much much better with changing temps etc. Also switched over to modelled fuel which works well.

So just fine tuning things, because my outer injectors are 1000cc and spray at a reasonably low pulsewidth, injector timing is something worth spending time getting right. 

I tested this out and found that at lower rpm (when mainly using inner injectors) it's best to spray very early, onto the back of hot valves and let it vapourize the fuel.

But as RPM goes up and switches over to outer injectors, it prefers the injection timing to occur as the valves are open and air is flowing into the cylinder. Which makes sense!

I tested this by statically settting the injection timing to one setting across the whole rpm range, datalogging a run, then incrementing the timing forward, and testing again.

Whereever the AFR shows as richest, that's where the best injection timing exists, as it's more efficiently mixing air/fuel so there's more fuel left over on the way out.

The below graph shows degrees before TDC combustion on the left hand side, and RPM across the top, and the air fuel ratio in each of the boxes. Yellow highlights the best AFR acheived for each RPM range, it's pretty clear to see the trend where it starts transitioning after 5500rpm from 450BTDC down to 250BTDC.



Edited by Davidv

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Oh hey! 

Havent been up to much with the car lately... I moved to the South Island to take a job in the motorsports industry, so funnily enough I actually ended up moving right near that track shown on the post above. 
It was awesome down there, but some life complications meant I needed to come back.
Some interesting stuff has happened between now and the last time I posted though I guess...

Firstly I had the windscreen smash which was fun! 


Then I competed through the time atttack series which was good fun, cut a little bit short by me moving away. But I was determined to make my "Street class" car as streetable as possible... Drove it to-from events and even used the car for camping near the events.


At one of the events I had one of the outer injectors in my staged injection setup fail - due to a rusty fuel tank and blocked up fuel filter which obviously let some debris through. 
So I had to roadside retune the car back to primary injectors only, then set a new fastest lap once the engine was running right. 
Since then I switched to a Seimens 850cc "shorty" injector, this gives me more clearance to the bonnet which was needed.

I made up some MSpaint style stickers for the numbers that I needed for the race series, also at the event furthest from home (about 6-7 hours drive) I ended up having the front universal joint in my driveshaft explode which sucked! 


Ended up getting towed all of the way home by some friends who unloaded their car off the trailer so I could get home. Which was much appreciated.

On the ECU side of things, I've got a few changes to plan coming up. 

I have just been working through populating the table to run my tacho as a combined tacho and fuel economy meter, using virtual aux conditions to switch between them automatically depending on what the car is doing. 
So currently I am thinking that when RPM is between 2000 and 4000, rate of acceleration below (something) and speed is above say 60kph the tacho switches over to the fuel economy meter. 
I dont see a way to achieve this apart from wiring two auxiliary outputs to the same tacho input, and switching between them using virtual aux. But I've got some left over so that's fine. 
I also want to setup something using CAN, I have been meaning to double check the accuracy of my analog wideband input so I might kill two birds with one stone and buy the link Can wideband module some time soon.
I've got a lot of DIs left over so will be looking at setting up wheel speed sensors as well, it will be interesting to see how much my LSD is slipping or locking under different circumstances.
It will be interesting to have a play with the traction control system when this is setup, not that a car with this power level particularly needs it. Might come in handy on wet trackdays though! 

I saw a cool idea where someone was using a K type thermocouple dragging against a brake disc to measure brake temperatures. I've been meaning to get some temperature paint or similar to find out how hot the front gets, as I wear out brake pads quite quickly. 
So for sake of interest I might do something similar while I'm setting up wheel speed sensors. Or maybe even a K type just sitting against the brake pad, I guess that's really what you're trying to measure and prevent from overheating.

It might also be fun to setup 4x EGT or 4x wideband, one for each runner but would look at doing this with a CAN based solution.

Apart from that not much else going on, just driving the car and enjoying it.
I like having the car NA and fairly simple but realistically for the time attack stuff I've been doing this means my car is mid pack at best. 
It's heeaapppss of fun though, with some great people and I still wince at the extra engine bay complication of forced induction. As the whole point of this car is to keep things simple. 

I have been having some thoughts lately about starting a new build using maybe a Suzuki cappucino or a Honda Beat. 
Just because they are awesome, and I like the gimmick of tiny cars. Both options will most likely be slower than my existing car haha.
Maybe a Toyota MR-S or similar would be a more sensible starting point.
(Or just go on holidays to Fiji etc instead and enjoy the car I've got!) 

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Cool man, sounds like you've been getting out there and enjoying the car. Isn't it funny how breaking the car miles from home opens the opportunity to meet like minded people and make new friends. Thats what I love about cars, the joy of machine and the fact it brings people together.

Quite like the idea of the K type on the brake disc, I would never have thought of that, you could always drill a small hole into the friction material of the brake pad and force the tip of the thermo in there?

I'd sat stick with the car, i've always quite liked the idea of taking a car and evolving it continously which is what you've been doing and thats always appealed to the engineer in me. You've made something unique and its truly yours, i like that.

Keep going with it buddy and next time get some on track footage ;)


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Yeah I definitely wont be selling this one... I dont think I'd ever find another one. 

Most of them rusted into dust about 10 years ago and they were uncommon and unloved compared to some of the other Toyota models of the era. So most just got binned as soon as they got rusty. 

And yes I've been a bit slack at getting track footage, things become a bit more complicated when I'm fitting semislicks each event and carting around all of the tools etc in the car. Feels like my day is busy enough already without worrying about camera stuff. But definitely a good keepsake.

The factory 4AGE Carinas essentially had an AE86 drivetrain in them so they were the first to get harvested for parts. 
I've been thinking about building a campervan as well, perhaps just keep this and make a start on that some time soon. I wonder what weird and wonderful features a G4+ could control for a campervan haha.

Edited by Davidv

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One thing that I've been curious about lately is advancing cam timing at part throttle for better fuel economy. 

So I did some tests, where I set the timing all to 0 degrees, then 10 degrees, etc, and then went for a drive at a set rpm on the same stretch of road with cruise control and closed loop lambda turned on.

Interestingly, 0 degrees advance clearly gave the best results. At first I felt satisfied with this, but then the nagging problem in the back of my mind... Toyota documentation says that advancing the cam "about half way" yields best economy.

So I took a closer look at the logs. When the cam advances, at same throttle angle, the MAP sensor reading goes up! In one case, up 60% higher. 
So the ECU is of course trying to dump fuel in, and pulls the ignition timing back which is why the economy was notably worse even though Closed Loop Lambda was trying its best to salvage the situation.
Why does the map sensor value jump up? Because of internal EGR, when you introduce cam overlap, the low pressure in the intake manifold and high pressure in exhaust pulls exhaust gas back into the inlet manifold which raises its pressure.
So this is obviously why the factory ECU uses a MAF sensor rather than MAP - A map sensor is including some "dirty" air in its readings (which has no oxygen left in it) where as a MAF only reads fresh air coming in.
Since the factory ECU only has a narrowband sensor, using the internal EGR method allows it to run a greater airmass to reduce pumping losses while still operating at 14.7:1 as the recycled air has little or no oxygen left in it.
Pretty clever.

So I thought I'd wire a MAF sensor back into the car. 
But this presents the next problem, how do you get the 0-5v signal of the MAF into a grams/sec that the ECU needs for a calibration curve.
So for starters I was just logging raw MAF voltage output, so depending on airflow it spits out somewhere between 0-5v to ECU
My ECU currently has load source as MAP sensor, and one of the values it logs as part of the modelled fuel calculation is "Grams of fuel per cylinder Estimated"
So we need to turn this into a grams per second, so some maths to create a custom field in Megalog viewer and now I've got Grams per second which I can compare to voltage:


Which I can then use as an axis on a scatter plot, which shows me a very rough outline of a MAF curve starting to form...

So I rough out a voltage vs grams per second to put in the calibration in Link

And then go for another drive and do same thing again in megalog viewer...
Starting to look better! 

(It would be cool if PClink allowed Maths functions like this... Just saying)

Then from here have updated the MAF curve again to suit the trend seen there. 

I think another 1 or 2 iterations of this and I'll have that low airflow area cleaned up.
If not, I will just switch to map or alpha N based tune around the areas where it sucks.

But from here, once the MAF sensor data is accurate I'll build secondary ignition and fuel tables which have MAF as the load axis. 
Then I can start experimenting with cam timing at part throttle some more, without my load axis going bananas (map sensor value changing a lot)
In order to find the sweet spot for economy though I really need to play with a few variables at once. 
As when you're introducing EGR gas, you might start getting misfires at 16:1 where as this is most economical if you are running no overlap. 
And when you introduce EGR gas you need more ignition timing as it slows the burn.

So I think I'm gonna make a little box that communicates over the CAN network that has a few potentiometers which log as virutal 0-5v which I can use as trim tables for ignition table, cam angle, goal AFR, and maybe a little display that shows fuel economy.
So I can very quickly go through a lot of combinations while someone else drives with cruise control turned on.
It's a lot of effort to make only a small iterative improvement to the car's economy, as it's already getting 7-8L per 100km if driven nicely. But it's always bothered me that I've had no way to quantify how to best set the part throttle cam timing so I'm thinking there's something to learn here yet.

I'll post the results once I've got my MAF curve dialled in nicely and I've put together a CAN box.

Also, at the same time as wiring in a MAF I thought I'd wire in an exhaust pressure sensor. 

I wasnt sure what sort of pressures I would see on an NA car, so I bought a 30psi sensor. 

I drilled a hole in a spare wideband bung, which then goes to a line of copper tube to cool the gas, then to a rubber line, then to the pressure sensor. 

Results are interesting! At high RPM (Or high mass airflow more specifically) the measured pressure actually drops. Down to 91kpa which was quite literally the last thing I was expecting hahaha.

Thoughts as to why? 

I think the airspeed past the hole in the wideband bung is creating a venturi effect and pulling the air out of the hose, rather than telling me what the pressure is.
So I am thinking that having an angled bit of pipe internally that either faces towards or against the flow will prevent this from happening. Or maybe upsizing the diameter of the tube that I am using as it's very small. (maybe 2mm ID)

The resolution isnt very good with a 30psi sensor so I'll perhaps switch it out for one from an NA car instead. I've got a spare Toyota one here somewhere. It doesnt really show any results that I was expecting though, so I might just ditch it from here.
Was worth it just for curiosity's sake though! 
More useful on a turbo car though of course.



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I asked over at another forum where you asked this, but this is probably a better place... does the change in backpressure have any relativity to the change in cam timing?

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It doesnt seem to, but it may be that the change is so small that it isnt able to be seen with a map sensor of this scale. And possibly because my copper line is too smaller diameter as well. 

I've parked this idea for now, I'll revisit it later on when I can redesign the pipes a bit better. 

But I'm just about there with my MAF based tune, might need a test driver at some point while I tinker if you're keen! 

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I've had a bit of a side project going on, I've wanted to learn about canbus so I bought an arduino and a canbus shield. 

Using some of the examples of code found on the net, managed to get frames both sending and recieving. I've never coded anything before so I had a few blunders like using = where I needed == and so on haha.

I'm using another shield on top of the canbus one that runs a screen, and have put together a box for it all.

The goal is to have the 4 pots control trim tables for goal AFR, ign timing, cam timing, and injector timing. So when I have cruise control turned on, I can quickly go through a lot of variations and have a graph showing fuel economy on the screen. 

I can also write a fuel economy value back to the ECU as well, and then have that log into the ECU's logs so that's cool.

Currently my car gets around the mid 7 litres per 100km mark, and I'd like to see if I can drop it into the sixes.

I'm most of the way there to finishing this thing so hopefully not too long till I can have a play around. 

I am thinking that for version 2.0 instead of pots I will have rotary encoders and then build an array which will act like a load vs rpm based trim table for each of the different areas. 
So it will hold the values in that area without affecting the others. It's a bit more complicated though so I'll just get this running as is for now.

Since I run 98 octane and MBT is quite far away from knocking I have also been thinking about using a feedback loop where the arduino adds a few degrees timing, see if this positively or negatively impacts economy, and then either reverts or keeps change. Then repeats, and maybe hones in by a smaller change each time. But I think that might work best once I've got some arrays setup, rather than just blanket applying a trim table to everything.



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My arduino based canbus box thingy has escalated into a digidash haha. 

So 3d printing a housing that will mount up to standard points and accept the standard loom plugs for power supply and so on. 

Lots of work left to do, but will be cool.


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