Better aftermarket computer - RX Turbo L .

[discopotato03]

My 86 or early series L RX Turbo has grown beyond its prehistoric EFI system and mechanical/manifold pressure sensing distributor ignition system .

That era was early in the days of production engine management systems and had really basic things like the twin throttle switches/vane type air flow meter/and conventional advance and retard distributor ignition system .

I have been down the road ages ago converting a carbureted car to EFI and let me tell you that updating a factory fuel injected car is much easier .
For starters the high pressure fuel system is in place and importantly the appropriate fuel tank .
Electrically the system is already set up for relayed computer and fuel pump wiring so all that has to change is the engine control wiring loom and the black box itself . I think I'll change over to conventional Bosch relays and power supplies just to have them new and reliable - known quantity .

Luckily Subaru used an optical Crank Angle Sensor in the later MPFI L Series and that makes life MUCH easier when setting up a complete engine management system . They are far more accurate that a modified distributor to give the four position and one reference pulse signals to the computer .
Provided the new box has a fast enough processor it can do all the crank position stuff in real time and also give faster more accurate control of large injectors .

I want to have sequential injection because that gives you the say in injection timing as in the injector close point in the 720 degree four stroke cycle .
I want to use injectors large enough not to be a limitation with E85 fuel and that means the ability to hose in something up to nearly 30% more than conventional ULP . I think the largest I'd go would be 440cc and from memory Mazda series 4 or 5 RX7 Turbos used such a thing and I believe some were high resistance ones which suit a ViPec V44 ECU .

Also TPS wise the later 4 plug MPFI EA82's use a potentiometer unit instead of the 3 plug systems twin switch one , they are interchangeable so go bolt .

More as it unfolds , cheers A .

[Gannon]

Luckily Subaru used an optical Crank Angle Sensor in the later MPFI L Series and that makes life MUCH easier when setting up a complete engine management system . They are far more accurate that a modified distributor to give the four position and one reference pulse signals to the computer .
.

Are you sure, i thought they had 4 position pulses and 360 position pulses. I was under the impression that there is no pulse to tell the ECU when Cyl No1 TDC is.

My guess is that is why they didnt have sequential injection and wasted spark ignition.

I suppose you could always fill in one of the little slots in the CAS dizzy to give your reference.


Disclaimer,... i could be barking up the wrong tree here

[discopotato03]

Gannon I'm pretty sure those four inner slots are different lengths and thats how the computer knows which cylinder pulse is which .

I don't think Subaru had any intention of running a multi coil system when a single one with rotor and four pole cap distribution system worked well enough .
Also the much tighter ignition timing control makes a big difference to emissions/consumption/drivability .
I'd say with the semi sequential injection they managed to get things clean enough for the 87-89 or whatever year ADR emissions regs . Trust me if they sold them in the US and particularly California our EPA would have been a piece of cake to get past .

Just off the phone from Scott at Insight and Ellie may be off for a new - er computer in a fortnights time .
Have to chase up some injectors ASAP and Scott tells me these ViPpecs cope well with modern 1000cc injectors in Two Litre Turbo engines so 440's in an 1800 should be easy peasy . He reckons to allow an extra 40% for E85 so going from ~ 225 to 440 would get the job done .

Also looking into electronic closed loop boost and idle control valves which these computers can run . Ellie with a steady idle , won't know itself .

Christmas at Colatown , cheers A .

[Gannon]

Sounds good

Keep up the essays and the pics. I dont own an EA82T anymore, so im gonna live my EA82T dreams through yours.

So are you gonna do individual coil packs or wasted spark? or are you gonna stick to distributor ignition?

You mentioned closed loop idle control.... XT6's had closed loop idle, and had an 'auxiliary air valve' or IAC 'idle air control' mechanically the same as early EJ22's (stepper motor), but just has an in and an out pipe and didn't bolt to the throttle body like EJ's did. Might make it easy to fab to your setup.



I have some diagrams floating around somewhere, i'll dig em up for your

[discopotato03]

I think the one in the picture there is a rotary valve IAC unit .
I'm just looking at my downloaded copy of an 88 Vortex Factory Fuel Injection system chapter , it covers the ER27 and EA82 , and it shows a valve like that one .
The Spider EA82 engine doesn't use that silly Auxiliary Air Valve (AAV) atop the water thermostat housing like the MPFI/T EA82's do in L's .
They have a different version which is similar to what Nissan uses - half dumb bell type .
If you look at the pics of my engine bay you can see the much neater carby style thermostat housing there .

Anyway the ER27 has IAC but no AAV , my Skyline has both .

If I can find a suitable IAC valve I should be able to replace the AAV and use its plumbing barbs to patch it in .

I think I may buy the system and wire in loom because we want to have a look at the layout of the harness and the best ways to get the relevant sections to each side of the engine bay .

Rather than go through the offside inner guard like the std engine control loom I think we can split the wiring and run it through the grommets behind the shock towers .
Meaning the wiring to the CAS/Dizzy and coil can go through the nearside and the injectors/cas/temp sensors/TPS etc through the offside .
Scott tells me that all the connectors are finger clip type unlike the _ _ _ _ clips used in the 80's era . This way we may get away with not having major connectors like std to separate the engine loom from the body one .
I REALLY love it when engine control looms are totally divorced from the rest of the cars body looms - so easy to fault find and R n R .

The std EFI loom down to the big round connectors in the bay can stay because as I've said before no one is ever going to pay me what this Frankensteins cost so it may one day revert back to the Factory system to cut my losses . Be really easy to remove if this car got parted out too .

Night all , cheers A .

PS : Gannon , scroll down through this thread and you'll see pics of a Nissan optical CAS type disc for a six cylinder . Note the inner 6 slots increase in length/arc to differentiate each cylinder .
Basically it would tell the computer which cylinder (in the firing order) is next to TDC rather than waiting till the starter wound the engine round to TDC No 1 to get a reference pulse and start doing the 153624 ting - or 1324 in a flat fours case . Quicker cleaner starting in that oh so cold and dirty first fire up phase .

http://forums.hybridz.org/showthread.ph ... l+CAS+disc

A .

[discopotato03]

Too early at 1 am to get my head completly around .
Read anyway .

--------------------------------------------------------------------------------

The ka24e ecu hardware is superior to any current megasquirt versions, and arguably, so is the code.
What you have with an OEM ecu of this caliber is a distributed network of control. Rather than have a single 8, 16, or 32 bit processor handling all CAS decoding and fuel/ignition output (core functions), the ECCS system off-loads to task oriented companion processors.

The main advantage to all of this and the reason the ECCS can effectively use such a high resolution CAS lies in interrupt timing.

A single microcontroller can easily handle the task of deciphering 720 degrees
of crankshaft rotation (or 360 degrees of cam) directly, provided resolution is available in the CAS (in the case of ECCS resolution is 2 degree per signal, on 720 count, when counting both rising and falling). What the single threading micro cannot be expected to efficiently accomplish is to handle this task when there are are others competing to be completed as well, such as possible fuel/ignition output. In microcontroller terms, this is called and issue with
"interrupt priority".

Alternatively, most modern aftermarket EFI measure the time (using an mcu counter) between current cam and/or crank sensor pulses, decide which count it wants to use for next operation, get signal, wait appropriate count and then perform operation. This allows for less signals to come from cam/crank sensor and and thus frees up time for other operations. These type of systems (megasquirt, AEM, etc.) cannot decipher the CAS like ECCS itself. ECCS does not assume for next signal, it performs its operation in current time.

In the ECCS system the 360 degree and the 90/sync CAS signals are fed to 2 and sometimes 3 different controllers, each having its own task within the system. The sequential operation of the fuel injector outputs is accomplished by using 2 of the controllers, one decoding the current cylinder in line, and the other using the normalized backside of the 90/1 pulse to fire an interrupt to start a counter on the 360 signal. This counter has a compare match, so as soon as the correct amount of 1 degree signals are read the controller will perform its operation.

The controller decoding the current cylinder in line does so by using the entirety of available CAS signals, not only the 90 degree sync. There are 3 distinct patterns on the CAS. Unlike aftermarket EFI, ECCS doesnt even measure this 90 degree pulse at all, it uses it to fire interrupts. These interrupts start and stop a counter on the 1 degree signal. Once this controller has decoded cylinder in line, it sends this data to the sequential fuel controller so that it knows which cylinder to output. It is constantly decoding the CAS using the same method, using the normalized backside of the pulse like I mentioned before, but it still needs to know what cylinder it is on.

This is all without even mentioning the controll processor yet, the one that actually extrapolates and sends the desired fuel injection and ignition timing values to the companion processors.

The control processor is indeed an 8 bit, a hitachi hd6303ycp , not much different than megasquirt. Its kind of neat in that it extra functions provided in the Hitachi version (in comparison to 6801 motorola counterpart) that make it comparable to the 68hc11 or the 68HC908. I use them quite a bit, especially in my output control routine. The controller does lack flash memory, but the system makes up for it with the more than adequately sized external memory.

To sum all of that up, think of the ka24e ecu hardware as everything that UMS aspires to be(distributed control), with a slightly older processor (that doesnt have to do very much), that is limited to using the nissan CAS.

I mentioned earlier that the code was arguably better than that of the megasquirt in any current versions, that is simply because we have no user guide to the ECCS system and must reverse engineer it. This would seem to make the megasquirt code better, but in reality ECCS is much more complex and refined.

Does your brain hurt ?

[Gannon]

Does your brain hurt ?

At 6am.... yes it does

[ORX-18]

Disco, please take it from someone who has burnt his brain beyond repair over computers. Just bite the bullet and get a haltech/microtech. for your application i would HIGHLY recomend a haltech F10X fuel only computer, and from memory there only about 900-1100 new with a loom. If you decide to go that route and need help with the loom i have a spare haltech loom you can borrow to copy. If you have ANY doubts about the fuel only capability i cna supply dyno sheets for 393whp and a 12.13 pass.

Cheers, allan

[Gannon]

I was thinking about it today, Schultzie used to run a Wolf3D with fuel and ignition. I think he may have even sent me a file that contained tuning information

I'll chase it up

[discopotato03]

ORX-18 you could not give me a Haltech EMS (engine management system) .
EFI Technology are or were no strangers to me and I remember spending a bit of time with them in their early days at Taren Point some 20 years ago .

You're talking about a different era back then with fairly basic 8 and 16 bit boxes like old F3's , IG4's , early E6's etc .
My first aftermarket system was an early E6 and while being GM Delco based hardware was nice the software really was crude - even for then . They could not see past bar graphs and basing zero as atmospheric pressure at sea level - PSIG . Trying to tell people that below zero (PISG) was a "negative pressure" is lunacy . You have absolute zero and everything above that is positive pressure - this is absolute pressure or PSI-A .

Essentially a lot of the problem was that they were trying to appeal to a DIY market and basing their target at people not really clued up enough to fit and tune EFI computers .
I also got sick of telling them that mapping in PSIG rather than PSIA is stupid and that the computing power to run sequential injection is not a luxury .

They kept trying to produce a cheaper Motec std unit and the E8 had a development phase that spanned too many years . I think eventually it hit the ground as an E10 or 11 but serious people out there kept buying Autronic or Motec systems and seeing the Haltech as the poor cousin .

EFI Technology bred a lot of smart people but they couldn't keep them inhouse , must have been better money elswhere .
Some years back one of the original founders of EFI Technology passed away and I feel the busuiness was never the same after that .

Anyway they moved from Taren Pt out in to Sydneys west and I haven't had anything to do with them since then .

My second system was an Autronic SMC and while it had some hardware limitations the software was much much better .

Once you've been down the road of fueling and ignition timing control you wouldn't have anything else - given a choice .
Mechanical and manifold pressure (actuator) systems don't even come close to the speed or direction in which timing changes can be made . With full engine management you can run much close to best mean torque timing everywhere and this means a surprising amount of the load range can be run at close to stoich or the chemicaly correct 14.7 to 1 AFR . It's this that gives you good throttle response and quite usable part throttle torque and good consumption .

The reason I'm looking at ViPec units is because some of the Nissan brigade are getting phenominal power and torque from their engines and they drive as well if not better around town that the bog std car did . Thats having your cake and eating it .

One thing about these units is that they have the ability to run TPS/MAP/MAF load sensing equipment . Most people agree that in a perfect world a mass air flow (MAF) sensor is the fastest and most accurate may to measure air flow by mass or weight , they automatically measure density as part of their wheatstone bridge circuitry and work very effectively .
The only real limitations of MAF sensors if their physical size and the fact that air needs to flow through them in one direction ie no reversions .
Your typical factory turbo engine these days has a throttle closed recirculation valve to keep the dryer spinning even it the throttle plate/s close quickly . The recirc valve usually plumbs back in between the MAF meter and the turbos inlet and if the air dump is big enough you can get reversion back through the MAF and issues like stalling . OEMS must have ways to get round this built into their std computers .

The ViPecs have the ability to use two load sensing options and one that is found to work well is TPS based with MAP or manifold pressure correction . The advantages of both sensors with the disadvantages of neither .
Maybe one day aftermarket computers will use any compination of the three for ultimate drivability/emissions/consumption .

Being a recent development the Vipecs had available more modern processors and injector drivers so running big squirters cleanly and acurately is not a problem .
Having things like closed loop idle and boost control means the box regulates these things to a finer degree .

The auto tune functioin when connected to a wide band 02 sensing system looks interesting and there is a youtube vid of it working on their website .

Running out of time again but will find a link to them in time .

Cheers A .

PS here ya go .

http://www.vi-pec.com/page_files/QuickTune.html
http://www.vi-pec.com/page_files/V44.html

[steptoe]

You can see why Brumberty Matt went dizzy and LPG on his EJ conversion - to avoid the above sort of additions and decisions, sort of my direction too with my EA82GT. Gees that is heavy reading at 3.30am Adrian, how much more power, drivability and economy out of your old EA82T are you aiming for when you're all finished?

[ORX-18]

If you are the kind of guy who doesnt mind spending the time doing fuel and ignition conversions then i couldnt recomend a Vi-pec more, i have one in my gtr. Ray hall is a fkn genius and put simply, he will bend over backwards to help you out, like free firmware and software upgrades for life. As for haltech's, they have come a dam long way, there not as bad as they used to be and they are VERY home/end user friendly. I have had a few experiences with wolf3d's and am not a big fan, but they do the job, EMS are just a plain headache fullstop, microtech is on par with haltech and motec is in my opinion, a little over rated in there lower end products. I tried a camira diy computer on an old datsun 1600 i had and it ended up bieng pretty big headache. If you love that sort of thing then the delco/megasquirt kits are a good hobby/tinker item but for ease of use, you just cant go wrong with pre assembled and set computers. If you want to know personal experiences with Vi-Pecs give me a pm. Same goes for haltech and microtech, my cousin has an ems in his sr20 powered gemini so i can always grill him about his loves and hates too if people want to know

[discopotato03]

Steptoe the thing is that the physical limitations of an EA82 are pretty much fixed so all you can hope to do is make them breathe as well as is practically possible and then lean heavily on the engine management system .

It's all part of the pick up a bit here and a bit there and do it enough times to achieve a significant overall gain in power/torque .

Lets face it , even in "ultimate" form no factory EA82T's engine control system is what you'd call sophisticated and that has to reflect in what they can be expected to achieve . The computers of the day were slow and chained to the semi sequential injection and really a smallish bore MAF sensor . Best fuel back then was rubbish but it was all they had to work with .

Something that may make some of you think a little is just how much modern controls help current engines work as well as they do .
Its been talked about recently that in some less wealthy countries EJ engines were available with a carburettor and distributor . At a glance it looks like a super easy way to get one fitted and running in a carbed L or MY but how much performance/consumption etc would it lose to the MPFI versions ?
Another way to view it is what would have been lost in the first RS's and WRX's if they'd had to use RX L type injection and ignition systems . They would have been worse off let me tell you .

Ok so to brain transplant an 86 RX Turbo like mine what do you gain .
1) Sequential injection and larger injectors
2) Electronic timing control + choice of 1/2/4 coils , tossing away long HT leads would be good .
3) No AFM restriction
4) New looms/plugs to replace the 23 yr old originals .
5) Tune to suit best performance/consumption - probably run cleaner than it does now .

I think people take for granted how sophisticated the electronics in modern cars is . Because the changes have been over time it isn't obvious until you jump out of a late car into an L Series and wonder whats wrong with it . 25 year old technology is whats wrong with it .

[Gannon]

Adrian sent me the photos of the CAS dizzy







And the Tech Edge wideband AFR display


So is there a difference in the slots to tell the ECU when TDC at cylinder 1 is?

[Outback bloke]

What exactly are you trying to achieve with your car? To me it sounds like you want to get as much HP as possible and do it with as little fuel as possible. If that is the case then you need to re-think your outcome a bit I think.

I'm not trying to be a PITA but it is a simple fact that you can not have the best HP figures in the game with out sacrificing economy.

ORX-18 already has shown that you can get big figures with relatively inexpensive equipment that will do the job reliably. A conservative guess at the cost of an Autronic compared to a Microtech/Haltech would be around $3500. Let's say you achieve exact dyno figures with both ecu systems. The fuel saving you will gain with an Autronic would take about 350,000kms to recoup. Add in the extra cost of dyno tuning to all the extra points and the cost variance if even greater.

Again, I have to ask, what are you trying to achieve with your EA82??? It is ancient technology as you have already stated. Sounds like flogging a dead horse with a very expensive whip to me. If you want a fast car then dump the EA and fit an EJ. If you just want a cruiser that goes OK you don't need to go to the extent that you are.

[brumbyrunner]

You're barking up the wrong tree Outback Bloke. He's trying to reinvent the wheel.

[Gannon]

Why does big power mean bad fuel consumption?

As long as your ECU can do 'closed loop' fuelling at cruising throttle openings (usually less than 10%) it shouldnt have anything to do with how much power you can make.

I do see what Adrian is trying to do here. I was doing the same thing with my EA82T. I wanted to know how far i could push it, i enjoyed fabricating and swapping parts to make it better, only thing was that reliability became an issue and i needed a reliable car as my daily driver, when the issue of swapping an EJ in came up, i figured i may as well buy a more modern car, hence why i sold it and bought an Outback. But i still wish i had my EA82T cos i miss playing with it.

[discopotato03]

LOL , what am I trying to achieve with my car ?

Well we though about re inventing the wheel but aside from having been done before you're stuck with going around in circles ...

I like the challenge of modernising the old L and making the best of what it had to start with . Any mug can throw an EJ in but I don't think thats in the spirit of things personally .
What I do believe is that modern externals and controlls can make more of a dinosaur EA82 than many would have you think . It's one thing to bag an old school engine but its another to put you money where your mouth is and rebuild it better than most or probably even the factory had it .

Outback Bloke its more like flogging , not that I do that because I have my trade based mechanical sympathy thing , a fresh horse with a reasonably expensive whip . That whip BTW is as sophisticated if not more so than many of the earlier EJ management systems - AND fully programmable . It is capable of being more flexible mod wise than any EJ computer - period .

Power means poor fuel consumption , you better go and tell the international race teams that one given that pit stops are being allowed less and less .
Poor fuel consumption if a factor of inefficient combustion or some kind of restriction or failure . There's no rule that says light loads the mixtures must be any richer than does any good . Timing advanced to give best torque (and volumetric efficiency) makes a big difference to consumption because it makes the most efficient use of air and fuel .

I won't speak for anyone else but my ideas of how to go about building a good road engine are very different to your average monkey see monkey do copy cat . I like to try to make an engine breathe better with cams and valve sizes aimed at good cylinder charging at the sorts of revs you use around town and cruising . We know theres only so much that can be done with EA82MPFI heads and any extra airflow has to be forced down the holes .
The EA's turbo is a dog and so is the header manifold , the L inlet manifold isn't much better and the best management rates with an AM/FM mono radio .

Like I keep saying the best legal local RX Turbos in Rally trim cranked out 190 horsepower using most of the std breathing bits .
I know that ALL the bolt ons I'm using are far better than what the Rally teams ran with and if anything the greatest difference is the cam shafts and you wouldn't want those in a street car anyway . Better manifolds and more modern turbos allows you to get similar airflow into an EA82T and without the extreme choppy cranky state of tune thats of little consequence in a competition car .
The dirt people used to break gearboxes in these cars for the same reasons that EJ converted ones do - more torque than the boxes were designed to take . If an EA can do it what have you lost over a heavier bulkier EJ shoe horned in the front ?

That aside , Gannon if you look at the optical disc you will notice the top inner curved slot is longer than the other three . The photo diodes output a signal on the rising and falling edges meaning the start and finish of those slots so the computer knows which is longest and representing No 1 cylinder . The third revision of this system , found in Nissan SR20's , has four inner slots of increasing length so , the computer can tell within the quarter of a turn (half a crank revolution) exactly which is the next cylinder approaching TDC at start up . The early version may have to wait nearly a full revolution of the CAS disc before it can find no1 and start counting from there .

My car earns its keep , it has about 317.5 K on it and thats 68.5 more than it had when I bought it .

A .

[Xtreme_RX]

When I had the EA82T in my wagon it ran115.2Kw at 4 wheels on the dyno.

This was running a Haltech F3 Fuel only ECU & STD Ignition @14PSI.
I also had larger injectors & my custom 'UP pipe'
It took 4 ½ hours to get the tune right & it still ran like a pig when it was cold.
Fuel usage was around 12 to 14 L/100kms around town depending on how hard I drove it.

Seriously for a daily driver stick with factory management the later 4 plug unit.
My 4 plug GLTA is 98Kw at the front wheels......

my 2c worth.....

[steptoe]

I reckon most of us can see Adrian is like many of us in here, just can't resist thinking you can do better, improve on factory, tidy a few things up, squeeze a bit more modern into an old fossil (Subaruousrex). Many of us have been there , done that and moved on, or like A. an me - still tinkering with the old stuff that needs no slime line fan or engineering certificate or nearly everything swapped out and jammed in to make it all work. i still chuckle at those having the readies to spend $3k on an exhaust sytem on a WRX - that's my whole budget for Cheap Grief ! Myself set out go Subie,turbo, LPG and get something flexible, driveable, reliable (getting there I think) and laugh again coz i got blown off at the lights by a chick in a newish Corolla. ( I hope I woulda had her if the speed limit did not apply or we hit the dirt )

Someone once (and only once) told me I looked like Forrest Gump. I reckon Adrian and I are gonna keep this tinkering up like Forrest did his running. Might just suddenly stop one day - satisfied with what we have done.

I just think it was good of Subaru to do a turbo version that has lasted this long for me to be able to tinker with on the cheap. The RX and Vortex turbos are in a class of their own in the Australian market from the mid 80's. What else was turbo ? The VL, CordiaLs, SAAB - all a little special in their own way. Adrian will probably still get blown away once finished , but then he has a Skyline too..don't ya still?