For the love of a tractor engine: The life and times of the 18R-G

[o_man_ra23]

Last time I needed a bung to fit an O2 sensor, I took the sensor to boltmasters, got a nut to suit, drilled a hole, then welded it into the extractors... piece of cake.

As for the learning experience bit... yeah, its great. I want to do a bit of playing around with the assembly code to try and give it some more features... will get to that when I get one up and going though I guess.

[matttai]

Ok running into some problems.
Letting go of accelerator pedal , when the revs start to go down the car with start to splutter.
If i do nothing and let it idle it will keep spluttering and the engine will then die.
Then when try pressing the accelerator pedal nothing happens (engine seems to splutter more) and feels like it is choking.
Is this a problem of the car getting not enough or too much fuel?
Only solution is to turn off car and restart it again.

Proving to be a problem when stopping at traffic lights

[timbosaurus]

I want to do a bit of playing around with the assembly code to try and give it some more features... will get to that when I get one up and going though I guess.

They give you the C code now. Advice = dont bother fucking with the asm.

But adding features like individual coil control to the C code is certainly possible

[matttai]

ok fuel problem sorted. the car was actually running empty - the fuel gauge is no longer accurate and 1/4 = empty!

[o_man_ra23]

Mattai... lesson learned the hard way I guess.

Timbo... I can program ASM a lot better than I can C, so I would be requesting the assembly. At least with ASM I have full control over what the registers and stack are doing. Also I can write more efficient code than what C writes, so I can get much quicker reaction times to things like knocking... where you want the reaction to the knocking to happen before the next spark. I guess they include the C code because C is easier for the average programmer to write... engineers are another kettle of fish though

[The Witzl]

Here's my result from yesterday's dyno day.... http://www.18rg.com.au/RA28/18rge-ms2.jpg

not too bad for a home tune.

[timbosaurus]

Timbo... I can program ASM a lot better than I can C, so I would be requesting the assembly. At least with ASM I have full control over what the registers and stack are doing. Also I can write more efficient code than what C writes, so I can get much quicker reaction times to things like knocking... where you want the reaction to the knocking to happen before the next spark. I guess they include the C code because C is easier for the average programmer to write... engineers are another kettle of fish though

Owen, do you know how many lines of uncommented ASM is generated from 137 pages of C code???

yes, I agree, you are talking like an engineer straight out of uni that rattles off all the lecturers justifications about why we had to learn asm, that are practical in programs the flash LED's.

In practice it's rarely used (even in GPS timing critical situations where things are measured in nanoseconds) anymore, and when it is, it is inserted inline in the C source.

And with the megasquirt processor running at 24 cyles per microsecond (1 microsecond being a 200th of a firing cycle at 10,000rpm) I don't think a few theoretical cycles of C code overhead is going to be the difference between knocking killing your engine and not

I wish you all the luck with working with the asm, but highly doubt you will have any success with it (despite your mass of experience after you graduated how many years ago? )

my 2c.

Timbo

[chris_rg]

MS-II is C i think. whereas MS-I is asm.

Also, I'm pretty sure any modern C-compiler will generate more efficient assembly than a human can. Heaps on this on the net.

[timbosaurus]

MS-II is C i think. whereas MS-I is asm.

Also, I'm pretty sure any modern C-compiler will generate more efficient assembly than a human can. Heaps on this on the net.

Correct on both counts!

Timbo

[RAd28]

can anyone suggest where i might find an Ignition only ECU? so far i've uncovered MegaJOLT (thanks Timbo) and MegaSPARK (which i believe to be associated with MegaSQUIRT)...

any other suggestions worth looking into?

[timbosaurus]

Hey RadMan,

As I mentioned earlier, the Megajolt option would be a great DIY option, however, I expected it to be able to drive coils directly which isn't the case.

If you just wanted to be lazy, and have all the parts for a full system, sent to your door and ready to wire up, you'd need...

*36/1 metal trigger wheel
*EDIS 4 trigger sensor
*EDIS 4 coil pack
*EDIS 4 coil pack driver
- cost would be about $200 shipped to your door from http://trigger-wheels.com

*Programmable MegaJoltLiteJnr ECU
- About $250 assembled, tested and shipped to your door from http://www.autosportlabs.com/

So you could have your whole programmable ignition system for under $500.

You could save about $100 by buying th MJLJ kit and assembling the ECU yourself with the comprehensive instructions included.

Unfortunately the EDIS units aren't available on aussie cars, so you'd always have to get that setup sent over... but you could no doubt save some money by waiting till something came up cheaply on ebay.

Jaycar also sell kits, but others would have more experience that I do on them, so I'll let them have their say

IMO $500 is a pretty good price for a full programmable setup, including coils sensors and trigger wheels.

Timbo

[o_man_ra23]

I built the Jaycar HEI ignition kit (not the multispark) and yeah, it worked fine. I ended up pulling it back out and putting in 21R ignition though, due to the more compact nature of the setup. Performance didnt change between the setups, and the only thing that the Jaycar kit did better was take the loading off the points.

[timbosaurus]

Hey Rad,

You are planning on ditching the dizzy, using a crank trigger wheel, and going wasted spark right?

Since you'll loose vaccum and centripetal advance if you do this, you'll NEED a programmable unit. The Jaycar HEI unit Owen built will not suffice.

They do sell a programmable unit, but it's is only single channel (you need dual for dizzyless wasted spark), and if i understand the website correctly it still wont drive the coils directly. This means you'd have to buy two units, buy two drivers, program and run both units in parallel, yadayadayada... dont sound like much fun to me

Timbo

[o_man_ra23]

What Timbo said is true... so for Gerrard's situation, it wont be suitable. Have you had a look at the MSD range lately?? The Jaycar device has its uses, but obviously not distributorless wasted spark.

[RAd28]

last time i looked at the MSD range my wallet crapped itself...

from what i found out, the MegaSPARK system was another DIY solution, but you need 2 "latching" hall effect triggers, and 4 rare earth (or similar i'd imagine) magnets... from what i could gather, you need 2 magnets, with N side out, and 2 with S side out... must be for switching the trigger on, then off ready for the next cycle?
i spotted Microtechs site where they listed hall effect sensors at $150ea + $20 for each RE-Magnet...

will look at that trigger-wheel site, see if it helps...