Ecu Experts I Need Your Help

[Mad-Max]

ok guys im looking for an ecu expert (or at least some one who can answer my question) for a bit of help with a project im considering to build.

what im wanting to know is how a stock ecu determines the timing advance on a rb20de/25de r32 ecu.

what sensors determines this or is it just the cas sensor?

Edited September 28, 2010 by Mad-Max

[mad082]

the crank angle sensor is what the ecu uses to determine what position the engine is at. the ecu then adjusts the timing around this based off TPS voltage, rpm and AFM voltage according to what settings it was originally mapped with. it will also take into account any readings from the knock sensors and also the temp sensor can play a part in this as well as it will alter the timing at different engine temps.

[Mad-Max]

the crank angle sensor is what the ecu uses to determine what position the engine is at. the ecu then adjusts the timing around this based off TPS voltage, rpm and AFM voltage according to what settings it was originally mapped with. it will also take into account any readings from the knock sensors and also the temp sensor can play a part in this as well as it will alter the timing at different engine temps.

ok forget about the fuel side of things and forget about the temp/knock sensors for a few mins here. i understand how they effect the timing when they need to

basically what im wanting to know is if the stock r32 ecu can work as a stand alone ignition system (only ignition) when only using the cas input to the ecu.

will it still advance the timing when rpm's are in play without those sensors (no afm, no tps)

Edited September 29, 2010 by Mad-Max

[blind_elk]

As mad082 has said, the function of the cas is to tell the ecu where each piston is in the cycle. The ecu then uses inputs from other sensors to calculate when to fire the spark.

So, no, it can't be used as a standalone ignition system if it is using only the cas as an input.

[Mad-Max]

As mad082 has said, the function of the cas is to tell the ecu where each piston is in the cycle. The ecu then uses inputs from other sensors to calculate when to fire the spark.

So, no, it can't be used as a standalone ignition system if it is using only the cas as an input.

and why not???????? id like some one to elaborate on this for me pls .... that doesnt really answer my question, try and think outside the box on this one....

i know the cas tells the ecu where each piston is in the cycle... inturn this signal that is sent to the ecu and lets the ecu know the rpm. and if the rpm of the engine determines the level of timing advance why would it need a afm/tps sensor to advance the timing surely it would have a base timing map it works from?

i always thought an afm/tps was more for the fuel side of things and only had a very slightly small impact on the timing

i know for a fact that with no afm and tps an rb25 will still idle with only a cas sensor and maintain base timing. trust me ive tryed but what i couldnt do was rev the engine and gauge the timing advance at the time

Edited September 29, 2010 by Mad-Max

[mad082]

the engine will idle, but it will use 15 degrees timing the whole way through the rev range. and without the AFM it will only rev to 2500rpm.

to go into a bit more depth i will post up an ecu map to explain it.

in this map you can see that there is a rpm scale down the bottom and a load scale across the top. the load scale can be calculated by either AFM, map sensor of TPS or a combination of them. without the load scale you would simply be using the first colum of the map. now in this case, at high rpm you would have the timing advanced by a massive amount, so it would be pinging it's arse off. however not all maps are like this one. some will have the first box of the column at high rpm only having 5 or 6 degrees, while at higher load it may actually be tuned for 20 or 30 degrees, so in that case you may be losing 10 or 20 degrees of timing. however by not having anything plugged in and just having it in base timing mode where it is locked at 15 degrees, you will be losing anywhere from about 10 degrees timing to 25 degrees timing, so it would be an absolute slug. even if you advance the timing via the CAS to get the base timing to 25 degrees, then there will be sections where you are still well under and places where you are still over. moral of the story, don't be cheap. get an aftermarket ecu

[Mad-Max]

thanx very much for that answers it exactly for me .... im just sortin out what options i have .... im currently lookin at another option of a standalone ignition system that can be pre programmed ect and programmed via a hand held/fixed controler either that or a re-programmed eprom.

if any one can think of any options i could use keeping in mind i only want it for the ignition and not the fuel ... fuel is only a bonus

[mad082]

this map shows it a bit better. look at the timing at 4000rpm. the top box is at low load (so light throttle). the bottom box it wide open throttle. there is a timing difference 23 degrees. now without the ECU recieving any type of info about the load on the engine then it will be running 36 degrees when it should only be running 13, so it will be pinging it's arse off. you could pretty much garantee the engine to fail in a matter of a couple of weeks (of regular driving), if not sooner.

[mad082]

generally any aftermarket ecu will be able to control just the timing alone as long as you still provide it with a TPS signal or a vaccum line for a map sensor.

i've just spoken to my tuner mate and am going to link him to this thread, so he can give you some more info.

[stanzasr20]

http://www.diyautotune.com/

http://nistune.com/

g`day mad max, i`m mad082`s tuner mate, these are two websites that you should look into, the megasquirt does do a stand alone

ignition ecu that can be run of a vn commodore map sensor to do your load and is cheap. the niztune on the other hand is a little dearer but has the abilaty to use all your stock sensors and you can just zero out all of the fuel settings in it, i myself have done this

with a straight lpg rb25det and it work fantasic.

hope this helps, gary, Gympie Mechanical & Dyno.

[zebra]

thanx very much for that answers it exactly for me .... im just sortin out what options i have .... im currently lookin at another option of a standalone ignition system that can be pre programmed ect and programmed via a hand held/fixed controler either that or a re-programmed eprom.

if any one can think of any options i could use keeping in mind i only want it for the ignition and not the fuel ... fuel is only a bonus

MSD-6AL is what you need...dont bother with trying to use EFI Stuff! the MSD, ICE, Accel etc gear is designed to be used with carburettors so they dont need TPS, and map/maf inputs, just program the ignition curve and and vacuum advance and away you go.

[Mad-Max]

MSD-6AL is what you need...dont bother with trying to use EFI Stuff! the MSD, ICE, Accel etc gear is designed to be used with carburettors so they dont need TPS, and map/maf inputs, just program the ignition curve and and vacuum advance and away you go.

yea ive seen this units used befor but i have little knowledge about them are they easily tuned and what can be done with them?? how are they tuned??

http://www.diyautotune.com/

http://nistune.com/

g`day mad max, i`m mad082`s tuner mate, these are two websites that you should look into, the megasquirt does do a stand alone

ignition ecu that can be run of a vn commodore map sensor to do your load and is cheap. the niztune on the other hand is a little dearer but has the abilaty to use all your stock sensors and you can just zero out all of the fuel settings in it, i myself have done this

with a straight lpg rb25det and it work fantasic.

hope this helps, gary, Gympie Mechanical & Dyno.

ahh good yea a map sensor i thought about that didnt think id need to use one tho.... and the megasquirt unit was what i was lookin at ealier

--> ( http://www.trademe.co.nz/Browse/Listing.aspx?id=321916315 ).

its compatable with knock sensor (which i want to run) and map sensor plus i like the fact i can plug it into a laptop and have a fiddle and since im using a series 2 vct head that would be very handy for controlling it

the other one i had a glance at was the silicone chip kitset from JayCar but i thought it might be a bit sketchy

any thoughts/ideas much apprieciated guys

Edited October 4, 2010 by Mad-Max

[zebra]

the 6al's are tuned the same way as most efi computers, plug the laptop in and away you go, they also come with half a dozen or thereabouts preset curves if you dont want/cant get to a dyno

[Mad-Max]

the 6al's are tuned the same way as most efi computers, plug the laptop in and away you go, they also come with half a dozen or thereabouts preset curves if you dont want/cant get to a dyno

oh wow thats good ...do they run ok with a cas? and can they be used with a knock sensor or is aknock sensor a bit obsolete with these?

[zebra]

They are designed for use with distributors, not individual coils, no knock control or anything like that.

what motor is it going on?

[Mad-Max]

They are designed for use with distributors, not individual coils, no knock control or anything like that.

what motor is it going on?

so it wont work with a cas sensor and wasted spark setup?

a non turbo rb30/25 vct hybrid

Edited October 5, 2010 by Mad-Max

[zebra]

Ill have a looksy in the msd manual I have floating around somewhere, Might have something in it.

[Mad-Max]

Ill have a looksy in the msd manual I have floating around somewhere, Might have something in it.

oh wicked i was looking at them to start with but i thought they were only for dizzys lol

the more info the better haha i couldnt find out much about them when i looked