998cc moke (1979) plan for full elec engine management and Turbo
Turbo Mini Forums

Hey guys

I am an aussie in vic and I have just bought a 1979 998cc moke that I have not yet picked up, its missing numerous engine ancilleries like distributor coil etc, which I feel would probably cost me a lot to source and I would likely need to spend time rebuilding these bits...

but to skip the whole frustrating stage of screwing around with distributors etc I have a complete Trionic 5.5 engine management system in my shed that I could use for this project, basically its an all in one EFI system that allows you to live laptop tune Ignition, Injection and Boost control really easily. Its Saab made, and I run the system on an earlier model Saab I own - it originally came out on saab 9000s.

It consists of
injectors, fuel rail, fuel pressure reg, intake temp sensor, coolant temp sensor, idle air control valve, throttle position, manifold air pressure sensor, ignition cassette, crank position sensor, and o2 sensor to run the system

the ignition cassette uses ionisation current detection to synchronise or determine what stroke each cylinder is on, it also detects detonation or the precursors of detonation before it occurs (by measuring voltage across the cylinder) it then has a few ways of preventing detonation by reducing ignition timing, adding fuel, and then finally reducing boost. its a very elegant and sophistciated system, with far more capabilites than megasquirt etc etc.

Basically from what I've read the big issue with fuel injection is the Siamese ports - I know everyone says semi sequential or TBI is the way to go for siamese ports
- Trionic has the ability to individually adjust each injectors fuel volume (via a correction factor) and also each cylinders ignition timing, as well as being able to change from fully to semi sequential if desired. This means I could theoretically add more fuel to the inside cylinders. it also has complete ability to alter injection angle (crankshaft degrees) etc to improve efficiency etc.

I have a wideband innovate MTX-L I use for live tuning.

so questions >

has anyone ever welded dividers into the ports - because I am going to go turbo I dont feel the slight restriction would be too harmful, it would also reduce the risk of the inner cyls leaning out.

whats a good turbo (and what cars do they come on second hand) no problem for me to build my own inlet and exhaust manifolds ive read people talking about G15?s? I'm thinking cheap/2nd hand, and if turbo needs a rebuild thats no problem.

in terms of making oil feed and return are there any threads on where these lines are usually plumbed in on 998cc engines?

what sort of engine mods do you need to do to make the engine turbo ready - like do you need different valves, rockers,. different head gaskets, etc??? - I should mention that the engine management system resolves knock before it occurs or takes drastic steps to protect the engine in the event of knock... with this system I've found I dont normally need to worry about reducing compression ratio, and I imagine on 998cc engines from the 80s probably fairly low already?

any other major considerations, other than space/location for turbo, I have seen people run the turbo off to the side to allow room and with a tig and some time dont see that being a particular problem,

thanks for any thoughts or questions or hints.

cheers

Ed

I'll only cover the EFI issues and leave the other questions to the rest..

Schrödinger's cat - so which one am I ???

Hey rod

thanks for the fantastic information.

well you can put any size injectors you like in the trionic system, it has a fuel injector constant that you can use which scales all the related fuel maps, and then you can modify the main fuel map or scale it down to reduce the duty with larger injectors.

the stock saab injectors put out about 345cc/min they're designed for a 2L engine. what flow rate injectors are people normally using?

the injection timing symboltable is based on rpm and load and allows you to be pretty precise in that regard.

I just thought i'd ask a dumb question but the engine inlet valve timing it is completely symmetrical right?

does anyone have the standard inlet valve timing in crankshaft degrees written down? it would help me get my head around how I am going to map it out.

but seriously, to remove all these problems could I just divide up the ports in the head by welding dividers in? has anyone done this?
seems it would resolve a lot of the tuning issues.

here is the crankshaft delay map


and here is my duty cycle calc lol - definitely need bigger injectors ha!

for my saab

so the two main things I wonder
- what duty cycle do I want to aim for
- what size injectors should I start with (thought maybe these saab ones could be a good starting point at 345cc/min

now i've never had to mess with the crankshaft delay map, so I am not sure about how to interpret it, I know that its referring to crankshaft degrees, and its obvious the delay reduces as RPM and Boost increase... ???

I suppose lets talk about my saab for example

if this is the cam timing (8 valve)
Inlet opens: 12deg BTDC closes 40deg ABDC duration 232
Exhaust opens: 62deg BBDC closes 2deg ATDC 244

I want the injection to be happening with the inlet valve open riiiight,

so how does that correlate back?

it seems like the delay map is telling it to inject onto closed inlet valves - ?would this be to reduce emissions when cold?

Edited by s900t8v on 18th Dec, 2016.

Assumeg a 7-port head is out of the question, then diverds are your best bet if you want to use the ECU. I doubt it can be made to do anything close to what the the siamese MS3 code is doing.

I toyed with the idea of dividing the ports, but ended up buying the SC 7-port head. There was a company called Manx that used to make a 7-port head out of a 5-port by enlarging the inlets. I've seen one and it was a LOT of work, and actiually the one I saw was not divided in the head, it just had large ports with twin 40 bolted on with special inlet naifolds (which were a lot of work also).

My idea was to put a 'tongue' on the inlet manifold that split the port when you bolted it on. I was going to machine slots in the head to hold it in place.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

www.twin-turbo.co.uk

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

thanks paul, I will keep the forum updated! I reckon I can makei it work well, the fact I can control individual fuel and ignition timing means that even if I ran it sequential without any sort of care or provision for the siamese ports the system will adapt and compensate for different intake lengths very easily... had simialr problems converting my 8 valve saab to trionic - everyone said it coudlnt be done, just needed a bit of brains!

looking forward to cracking on with it, thanks for the information!

found a post on the mustang forums who did a really good write up

http://www.stangnet.com/mustang-forums/thr...process.736061/

so based on the above

looking at the injection delay map (in crankshaft degrees)
a full cycle is 720 degrees. I think 360 degrees is top dead center and the start of the intake phase. OR its possible that for this map 0 is the start of the intake phase - either way the map is obviously injecting onto a closed valve for a significant portion of the map,

Inlet opens: 12deg BTDC closes 40deg ABDC duration 232
Exhaust opens: 62deg BBDC closes 2deg ATDC 244

means that in the scale of the map the intake valve is open from 348 degrees to 580 degrees. (for my saab)

now my thought would be because this is start of injection timing that the best thing to do would be just to set the delay to 348 degrees (or calculated just a little earlier to compensate for the delay from injector opening and for mixture to travel from injector to cylinder) on every single cell because the valve will not be open until that time irrespective of RPM or load.

the experimentation would be seeing how much earlier you could set it (as rpm/load increases) before it started to cause uneven fuelling the cylinders.

now I finally understand it!

the other big variable is if I can set my ECU which is fully sequential to run 4 squirts through 2 injectors, providing I use big enough injectors I wont have the problem of pulse overlap, but again this would be hard to measure and probably needs experimentation.

I am thinking of how to best create a manifold that would accomodate (all 4 injectors) 2 injectors per runner in such a limited space with a realistic fuel rail.

Edited by s900t8v on 20th Dec, 2016.

Depending on where you put the injectors, you will need to allow as much as 120-150 degrees of crank rotation for port travel time.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

wow that is a lot of time!

thanks for the info!

Trying to cover some of your previous questions...

All the normal cams are symettrical, it's only the so called "scatter" cams that aren't, they used different timings between inner and outer cylinders to try to minimise the charge robbing effect.

Given what you have said about the ECU, this does look possible but it's not clear if you can vary the injection timing (advance as you describe it) with load and/or RPM.
EDIT - just re-read your previous posts and you say it can, but can you alter it on a "per cylinder" basis ? end EDIT.
The travel time that Paul mentions above varies with RPM and you get all sorts of wall wetting issues at different loads and ideally you want to be able to vary the inner and outer cylinder pulses seperately (or run what we call merged pulse).

If you are going for large injectors and through open valves you want to aim for a duty cycle of less than 25%. Otherwise you will be hitting closed valves. Whilst that is quite normal on an engine with seperate ports, for all the reasons I mentioned earlier you don't want to hit the outer valves when they are closed (as it will just get sucked/blown into the inner next time around) although inners early is OK as they open first.
But that is <25% per injection pulse.
So if you use only two injectors and they inject twice, ie cylinder 2 followed by cylinder 1 (firing order being 1,3,4,2,1,3,4,2,1, etc) they only need to be sized for 25% whereas if you use four in the manner you suggest, all four would still need to be sized for 25%.
Providing the ECU uses common Mosfets for the output drivers switching to ground (which is the most common setup) you can simply connect connect the cylinder one and two output (and three and four) together to drive a single injector on each runner. This is exactly what Rover did with the standard four cylinder MEMS ECU on the MPI Mini. Just look at the wiring diagram for the MPI. You would then obviously have to ensure the timing figures you use don't overlap or, if they do (which is a valid way of working, the merged pulse I mentioned earlier) you have the pulse widths set to take into account only one injector is being commanded open rather than two at the same time.

This is all assuming NON-staged injection (staging is what some of us use (with a suitable ECU) to overcome the dis-advantages of large injectors at idle although my current setup idles fine (better than any carb) with two X 1000cc injectors).

Anyway, it sounds an interesting project.

Edited by Rod S on 21st Dec, 2016.

Schrödinger's cat - so which one am I ???

hey thanks for taking the time to reply

ok thanks that makes sense about the cams I didnt think they would be asymm just off the bat.

ok sounds good about the injector info, so I could just run 2 injectors by bridging two pairs of injector trigger wires together.

I have the ability to individually control fuel on each injector via a correction factor which would also help me to get the fuelling right
this is what the injection timing map looks like - the X axis is Manifold pressure and the Y is RPM. - its 'start of injection' timing.

what injectors are you using?
what manifold are you using - did you make your own?
do you have a build thread or any pics?

not planning on doing staged - I think I could with the earlier batch fire software and I could adjust each pair of injectors - but that seems to complicated for me at this stage.

hey a random thought, we all worry about charge stealing, but if you got rid of the divider wouldnt the open valve just suck the mixture down?

so the issue is I am stuck with a 998cc, there are not many 1275cc motors in aus anymore and the ones that are very expensive like 2.5k each! I do a lot of work with 2 strokes so maybe I can embrace some cylinder porting and get a cheap cam to give it a bit more kick!

the project itself is in parts, I am not 100% whats missing but there is a lot of work in it (at least its a moke not a mini right) but I am figuring the main plan will be to half assemble it, figure out what is missing, and make a decision re the level of restoration, but I think to pass roadworthy it will need a lot of money !

Schrödinger's cat - so which one am I ???

My build thread:

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=559956

998 with worked crank, lightened rods, Minispares Evo pistons, scatter cam, Turbo Phil 12G295 head, 1.3 roller rockers, straight cut box and drops.

Gt1752 on remote manifold. Tuned length inlet manifold - 400mm runner length. Impact of charge robbing eliminated (according to simulations).

MS3 driving 4 injectors, 2 primary and 2 secondary staged in on boost. LS logic level coils. Boost control, traction control, water injection control. Triple widebands.

Edited by Paul S on 21st Dec, 2016.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

the mosfets x4 driving the injectors (ecu grounds) MTD3055VL N-channel MOSFET DPAK SMD

the injectors I have


345 cc/min @ 3 bar fuel pressure
Static Flow Rate: 31.6 lb/hr @ 43.5PSI = 239.4 g/min = 349 cc/min (+/-4%) Dynamic Flow Rate 2.5ms pulse width @ 100Hz: 6.68 mg/pulse (+/-6%) Coil Resistance: 16.2 Ohms (+/-0.35 Ohms)
Physical Dimensions: EV1 Body Type
Connector: Minitimer (Bosch EV6)

most of the tuning I am seeing done here in aus is NA, whereas I come from turbo land and think its a waste of time spending thousands on cams when you can just go forced induction. if you know how to tune it and can make your own manifolds it wont cost you thousands.

Edited by s900t8v on 22nd Dec, 2016.

You will need bigger injectors.

You need around 1000cc/min per port for 120hp as a guide figure.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

right I get it now

so it doesnt matter if you have 4 injectors they still need to be able to deliver in a small injection window

how about siemens deka 850s

http://www.ebay.com.au/itm/Siemens-Deka-EV...q0AAOxykUZTjPL6

or bosch 1000cc? http://www.ebay.com.au/itm/1x-New-Genuine-...wEAAOSwstxVN4Ax

Thanks again paul!

I've used the Siemens Deka injectors on my last 2 builds, as much because you can sit them close together.

No real operating experience though.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Schrödinger's cat - so which one am I ???

hey thanks, ok I will look into trying the bosch injectors they are meant to be pretty well toleranced whereas the siemens have a rep of being fairly unreliable.

it's going to be interesting nonetheless!

what did you think of the idea of removing the port divider so the open valve can get access to the fuel sitting on the other valve? atomised mix will always take the shortest route, and technically fuel should never form on the back of a valve its too hot!?

Edited by s900t8v on 25th Dec, 2016.

hmm I am getting confused about this again

I need to keep the duty under 25% or just within the inlet valve open period right >

my question is
- is the need for huge injectors because at higher rpm if the injectors are not big enough they will overlap pulses which will result in loss of fuelling? or is it purely because they need to be big so to be able to inject enough fuel in the short period of inlet valve open.

Thinking about this more I am going to use a DIY flowbench when I get the car and test the head in its current setup, I have other figures of stock 998cc flowbenched to check my setup against. I am then going to with clay and some sheet metal install a full length intake divider and test the flow with full length dividers, if flow loss isnt catastrophic then I will use full length cylinder head intake dividers to remove the problem of
1) charge stealing
2) having to go to rather large injectors, worry about injection angle, and issues of poor idle because of dead time and inaccuracy with low duty cycles on large injectors. - meaning i can inject onto closed valve which will improve atomisation and reduce fuel consumption whilst maintaining power output.

my thoughts are
1) the limitation on power gains with EFI on siamese ports is injector sizing which ends up wiping out idle / low speed driveability and emissions right (so the fix is to go to staged which means more money)
2) I think that sometimes when dividers are done properly they help laminar air flow and increase velocity improving torque, because these cars are not insanely high revving in their natural state the potential loss doesnt strike me as being that great but it has to be tested. its like using a smaller carb throat on a particular engine and I think all the worry is in regards to NA vehicles - mine will be turbo.
3) if the cfm flow loss with dividers was minimal or able to be compensated with careful port modifications then the benefit could be better all round driveability on EFI and removal of the power output ceiling, without having to buy a 7 port head.

because I am turboing I feel the restriction on the inlet side to be less worrisome. the issue will be installing a reliable divider that is not affected by 10-12PSI of boost. I'd probably braze in a 2mm thick divider, and port the outer walls to improve flow. I guess the point is that the choke point is at the valve and not in the inlet tract (although the intake manifold is a restriction), hence why porting the inlet and not around the valves doesnt really do much except for race porting, this combined with a proper flowing manifold i think would potentially work...

Edited by s900t8v on 25th Dec, 2016.