Apexi Super Ignition Timing Computer

[dontfeelcold]

Just an idea, seeing as the stagea needs the standard ecu to run the auto gearbox, can't you leave the standard computer hooked up to the loom, still receiving inputs from the sensors and sending instructions to the auto, but not let the standard computer tell the injectors, timing etc what to do. Then, get a Power FC and splice it into the loom and away you go.

Might require some fiddling here and there to make sure that the correct voltages are going to the ECU's.

Just throwing the ideas out there.

[Sydneykid]

Just an idea, seeing as the stagea needs the standard ecu to run the auto gearbox, can't you leave the standard computer hooked up to the loom, still receiving inputs from the sensors and sending instructions to the auto, but not let the standard computer tell the injectors, timing etc what to do. Then, get a Power FC and splice it into the loom and away you go.

Might require some fiddling here and there to make sure that the correct voltages are going to the ECU's.

Just throwing the ideas out there.

Nice throw..........

The standard ECU doesn’t “run the auto”, there is a separate transmission ECU for that. What the standard ECU does is cut and/or retard the ignition on the gear change. If the standard ECU is not running the ignition how does it cut/retard it?

You could use an aftermarket ECU to run the injectors, but you still can’t tune the ignition timing. So it is arguably better than an SAFC/DFA on its own. But is certainly inferior to the SAFC/SITC combination.

cheers

[NewKleer]

would something that could control ign timing and fuel adjustments independant of each other (ie, leaning fuel wont change ign timing at that load point and vice versa) be useful?

and how much resolution would be required for it? whats the minimum load point interval that would be acceptable?

as soon as the first version of my consult lcd project is done, i want to look at doing something that will allow adjustments to fuel/ign independantly of each other, but the main drawback will be relatively slow response times (it has to actively monitor/adjust, can be as slow as 100ms real world) which effectively puts an upper limit on how often (and hence resolution) of the adjustments.

[CruiseLiner]

so whats the process of using one of these? how do u set the timing etc exactly? its not for my car but a mates running a SAFC and he is thinking of adjusting timing using one of these but we are unsure on the way to set the timing up using one

anyone mind explaining it?

thanks

[Sydneykid]

A SITC is to ignition timing what an SAFC is to AFM voltage. The SITC sits between the CAS and the ECU. It takes the signal from the CAS and changes it (advance or retard) according to the correction factors you have dialled in (yes, it has knobs). This means the ECU still runs the igniters, the ECU can still cut the ignition and the ECU can still retard the ignition.

That’s why the SITC is good for an auto, all the shift programming for gearchanges still works. The ignition timing might be a bit retarded or advanced from the standard mapping, but the shift quality is pretty much exactly the same as standard. Think of an SITC as like someone sitting under the bonnet and rotating the CAS to give you the best ignition timing.

In this regard an SITC is not the same as other ignition tuners (such as EManage), that sit between the ECU and the igniters. They take the ignition signal from the ECU and change it according to the correction factors you have programmed in. The problem with that style of ignition tuners is they have to match exactly the igniters’ requirements. This is where EManages in the past have caused problems with burning out igniters. Plus they loose a little shift quality compared to the SITC.

As you can see from the early pictures in this thread, the SITC (being a several year old design) has 5 knobs for adjusting the ignition timing in rpm range steps. It also has good interpolation between those 5 steps ie; it’s not really a step change in ignition timing, more of a slope.

If Apexi sold a later generation SITC with laptop programmable ignition timing of multiple load points (say 40) instead of the 5 knobs (RPM) I reckon they would sell heaps. But they haven’t, so the best you can do is try and buy a used SITC when one comes up. They are in high demand and sell fast, so make sure you are ready when they come up.

To answer newkleer’s question, what you need to do is have a look at the CAS signal with a cro. Take that as input, manipulate the timing of it (+ or - 25 degrees max) and then duplicate the output so that the ECU thinks it is coming direct from the CAS. Then you have to make it programmable according to RPM, 20 steps may be enough, 40 (that’s every 200 rpm) would be more than enough.

Cheers

PS; I have through thsi thread and updated the links since they were lost in the gallery update.

Edited July 13, 2006 by Sydneykid

[NewKleer]

To answer newkleer’s question, what you need to do is have a look at the CAS signal with a cro. Take that as input, manipulate the timing of it (+ or - 25 degrees max) and then duplicate the output so that the ECU thinks it is coming direct from the CAS. Then you have to make it programmable according to RPM, 20 steps may be enough, 40 (that’s every 200 rpm) would be more than enough.

Cheers

i wasnt thinking of doing a direct piggyback type one like SITC, but via consult. you would map out adjustments for fuel and ign, and these would be applied on the fly via the active test functions of the consult protocol.

its nature is slightly unreliable (due to serial comms) and response time wouldnt be super, but i imagine its effectiveness, at least for fuel mixtures would be better due to not being a piggyback and hence not messing up your ignition timing, so theretically you wont have the issue of ign advancing if u make huge leaning out changes to top end. wouldnt be better than an SITC though for ign (being plug and play would be the only advantage), however it may be good enough to be useful.

hence what i was mentioning about before at the least amount of load points for it to be effective/better than using nothing. the problem is not its resolution (mapping resolution would only be limited by the amount of memory required to store the offsets for each point) but the response rate - eg if you rev from 0-8000 rpm in one second in neutral, then you are essentially limited by how quick the adjustments can be made to ensure your not going to be running incorrect or damaging offsets in the wrong rev ranges

i never anticipated doing anything with the ign timing (perhaps aside from consult controlled static ign timing adjustments, which would just be set once and left, and not modified on the fly) due to that, but would be interested if itd be of any use.

[Sydneykid]

i wasnt thinking of doing a direct piggyback type one like SITC, but via consult. you would map out adjustments for fuel and ign, and these would be applied on the fly via the active test functions of the consult protocol.

its nature is slightly unreliable (due to serial comms) and response time wouldnt be super, but i imagine its effectiveness, at least for fuel mixtures would be better due to not being a piggyback and hence not messing up your ignition timing, so theretically you wont have the issue of ign advancing if u make huge leaning out changes to top end. wouldnt be better than an SITC though for ign (being plug and play would be the only advantage), however it may be good enough to be useful.

hence what i was mentioning about before at the least amount of load points for it to be effective/better than using nothing. the problem is not its resolution (mapping resolution would only be limited by the amount of memory required to store the offsets for each point) but the response rate - eg if you rev from 0-8000 rpm in one second in neutral, then you are essentially limited by how quick the adjustments can be made to ensure your not going to be running incorrect or damaging offsets in the wrong rev ranges

i never anticipated doing anything with the ign timing (perhaps aside from consult controlled static ign timing adjustments, which would just be set once and left, and not modified on the fly) due to that, but would be interested if itd be of any use.

OK, I think I have finally got it. I didn’t have my head around changing the standard ECU mapping on the fly via the Consult port. So it’s not a permanent change, you simply send changes to the mapping from a lap top or a palm. Which would normally have to stay plugged in all the time. So what you are making is a lap top/palm “replacement” that has the mapping changes programmed into it.

Have I got it?

cheers

[NewKleer]

yeh thats it, you could do something like that via laptop/pda, but that would even be slower than in hardware - so my idea would be to use a microcontroller to do it from (and hence no need for laptop/pda there permanently). since u cant save any changes made via consult, its an active thing

i would base it upon the consult lcd display im making, since the hardware etc is already setup for it, would just require different firmware etc on the microcontroller that runs it.

so because it uses consult, theres no hardware setup, just plug it in and go. however, the drawbacks are that communication is serial, and each changes requires you to tell the ecu to stop sending data before making the next change request (just adds a bit more time)

serial not a huge issue in itself, but the 2 main factors is it does add lag in the region of milliseconds somewhere from when it can read ur current rpm/afm, and when it can then apply the changes, and secondarily, if u pull the plug out in the middle of the car running, it will be "stuck" in the current adjustment until car is turned off/on again (or its plugged back in)

so the idea is to have a 2D map of RPM vs AFM (another advantage over piggybacks that are traditionally 1D maps), with adjustments (+/- % for fuel).

one extra thing to be noted, is that any change in adjustment (ie from one value to another) will result in adjustments going briefly back to normal/0% adjustment (between the time you tell the ecu to stop with current changes, and apply new ones). so the less "jumping" between different % adjustments the better. ie it will be better to leave it at say +10% for xxx rpm to xxx rpm, than going to 11% for only a few hundred rpm, then back to 10, as when it changes to 11, and then back to 10, it will briefly be running

not sure how much of that is understandable

Peter

[Sydneykid]

Having got the first bit, I will have a go at the second part.

So the mapping adjustments aren’t absolute, as in;

open the injector “now”

close the injector “now”

They are more like “open the injector 10% longer” than would be the case if all else was equal. If that’s right, then in reality all it is doing is applying a correction factor.

For a lightly tuned engine (more boost, FMIC, turbo back exhaust etc) the changes are actually pretty broad based. You don’t need hundreds of load points, 20 or so does the job just fine. This is because the standard mapping is the right “shape” it just needs to be moved up and down a bit. It is one (if not THE) big advantages of an AFM sensor driven ECU.

Even a high flow or mild upgrade turbo using the standard injectors is pretty much the same It’s not until you get to injectors and AFM upgrades with large turbos that the basic “shape” of the mapping gets out of line. That’s when you need lots of load points.

I wouldn’t get carried away with catering for that sort of level, because the standard ECU starts to have limitations in other areas.

A question (or two);

1. can you modify the top speed (180 kph) limiter this way?

2. what about rpm limiter?

cheers

[NewKleer]

thats right, theyre correction factors or multipliers. from memory fuel is +/- x%, and ign timing is +/- x degrees (so fuel is a multiplier, timing an offset)

unfortunately fuel/ign are the only interesting things you can do. you can do other random stuff (alter iaac valve, temperatures for fans to go on/off, cut out cylinders(cant remember if its ign or fuel), and turn the fuel pump on/off), but none all that useful for everyday running

for all other things, such as rpm limited and speed cut, you have to manually remap/edit the ecu rom.

[Sydneykid]

Bump for the people who can't use the search button.

cheers

[FLYSLY]

So SK have you got any results for us as to how much the SITC has helped?

ie: Dyno tune with SITC and DFA power figure and fuel economy over standard fuel economy?

I just bought one of these off ebay the other day still awaiting for it to arrive so i would love to know in what areas it has helped your power curve etc...

Simon

[Sydneykid]

So SK have you got any results for us as to how much the SITC has helped?

ie: Dyno tune with SITC and DFA power figure and fuel economy over standard fuel economy?

I just bought one of these off ebay the other day still awaiting for it to arrive so i would love to know in what areas it has helped your power curve etc...

Simon

Sorry Simon, I have been road tuning using the Tech Edge A/F ratio meter. So I haven’t had the Stagea on the dyno, there just never seems to be the time. Plus I have a few incomplete mods, which I really want to finish before I stick it on the dyno.

I can tell you that the SITC on its own makes ZERO difference to the fuel consumption. Tuning the A/F ratios using the DFA made the most difference, after the exhaust system upgrade (split dump, Magic cat and Nismo cat back) of course. I am still playing with the DFA tune, it needs to be a bit leaner. Which I couldn’t do without the SITC, the DFA was advancing the ignition (via lowering of the AFM voltage). So it was getting a bit of pre-ignition, the SITC enables me to retard the ignition (back to where it was) and therefore avoid the pre-ignition problem.

cheers

[FLYSLY]

Thanks for the info SK i have read through this whole thread and the amount i have learnt just from reading your posts is phenominal.

You are a credit to yourself.

Once i get my safc i will get the lot tuned and i will let you know how i go.

Simon

[FLYSLY]

One other thing, with the SITC and SAFC would i be able to run aftermarket camshafts?

Cheers for any help SK

Simon

Edited September 7, 2006 by FLYSLY

[Sydneykid]

One other thing, with the SITC and SAFC would i be able to run aftermarket camshafts?

Cheers for any help SK

Simon

Tomei Poncams would be fine, but I wouldn't go any longer duration or higher lift than that.

cheers

[FLYSLY]

Got my SITC today so stoked, now gotta search for a nice and well priced SAFC NEO

[munchstagea]

Got my SITC today so stoked, now gotta search for a nice and well priced SAFC NEO

Have seen some on Ebay for $240........... plus $240 postage! Wonder how many people will get tricked by that? Still seems reasonable for a Neo SAFC if you really want one?

[FLYSLY]

yeah i have seen those ones too, but i wasnt stupid enough to fall for it lol.

you can get them from a sponsor on ns.com for 480 delivered.

[AlexCim]

I was looking on eBay US for around ~200USD + ~30USD delivery.

What sponsor on NS does them brand new? (SITC i am saying)