Apexi Super Ignition Timing Computer

[Sydneykid]

I bought an Apexi SITC today, so I can have a go at changing the ignition timing independantly of the Jaycar DFA's effect on the AFM voltage.

Judging by the amount of correction I had to apply after retarding the exhaust camshaft timing 4 degrees, I figure I am going to need to use the DFA for some serious A/F ratio tuning. Especially with the GCG Ball Bearing High Flow turbo, split dump and 3.25" exhaust to go on. The only draw back of tuning with the DFA (as with all AFM voltage benders) is it advances the ignition at the same time as it leans out the A/F ratios.

The SITC will enable me to correct for any excessive advance while it is on boost and at the same time add as much advance as it will take off boost. This should help the fuel economy even more and improve the response. Maybe even help the boost build.

The Stagea is going to have a glove box full of piggy backs, such is the price for having an auto.

PS, For some reason I can't fathom, Apexi decided to no longer make the SITC. So if you are thinking of getting one it means shopping around for a used one. I strongly suggest you get in quick when you see them come up, they are most sought after around the world.

[GTRgeoff]

Mr. Gadget has entered the building. Gotta love your tenacity SK.

[Sydneykid]

The first job is to identify the correct wires into the ECU from the CAS. That would be 44/45/46 according to the trusty Stagea ECU pin out drawing;

For the sake of completeness I will post up page 2 of the Stagea ECU pinouts, it may be useful for other projects.

Next job is to scan the SITC Instruction manual:cheers:

Edited July 13, 2006 by Sydneykid

[Jay95R33]

Just for info, when I wired the Unichip up on my old Stagea I had to tie pins 44 & 45 together, then run it through the Unichip.

Not sure if you'll need to do the same with the SITC though.

Both 44 & 45 are marked as "Crankshaft position sensor 120 degrees (REF) signal". Not sure why there are two wires doing the same signal, but there is...

J

[pshrdeta]

dont jaycar have an ignition control module?

ive bin reading your ibc and dfa thread and am interested to see how this one goes........

[Sydneykid]

A bit of an explanation as to how the SITC works. It intercepts the signal from the CAS and them applies a retard or advance into the signal it passes to the ECU. This means the SITC can trick the ECU into firing the plugs earlier or later.

This is good for an auto as it doesn't interfere with the ignition retard and cut that the ECU applies on gearchanges. That's why the SITC is a far superior solution than the interceptors that sit between the ECU and the plugs. They really do cause problems to the smoothness of the changes and ultimately the life of the auto.

The SITC has 5 load points, 800rpm, 2,400rpm, 4,000rpm, 5,600rpm and 7,200 rpm. With the usual excellent Apexi interpolation between the load points. I have no idea why, but Apexi in the SAFC, SITC and boost controllers have great algorithms working out the corrections between what seems like a small number of load points. The smoothness of an SAFC corrected A/F ratio trace is a prime example.

The wiring diagram for the Stagea;

Enough theory, the next sequence will be the fitting

Edited July 13, 2006 by Sydneykid

[Sydneykid]

dont jaycar have an ignition control module?

ive bin reading your ibc and dfa thread and am interested to see how this one goes........

Unfortunately no, Silicon Chip haven't done one yet. I am hoping this will put some pressure on Julian to have a go.

[pshrdeta]

Unfortunately no, Silicon Chip haven't done one yet.  I am hoping this will put some pressure on Julian to have a go.

http://www1.jaycar.com.au/productView.asp?...x=&SUBCATID=347

pretty sure thats an ignition adjuster

although i maybe wrong...........

[B-Man]

Shouldn't be too hard for SC to one of these - essentially the same concept as the DFA et al - Maybe a different PIC and some additional smarts.

Looking forward to seing the results and learning some more stuff from you SK - Thanks for your great work so far - I got me a DFA the other day for the GTS4 - Lots of learning to do now

[Gav]

 With the usual excellent Apexi extrapolation between the load points.  

Nice write up! Have already decided on just this approach for the missus 4 door auto Skyline (although she doesn't know she's getting one yet!).

For the sake of being pedantic, extrapolation is estimating a value outside the range of measured points, interpolation is estimating a value that sits between two measured points. Gav

[Sydneykid]

http://www1.jaycar.com.au/productView.asp?...x=&SUBCATID=347

pretty sure thats an ignition adjuster

although i maybe wrong...........

When I read the fine print...............

"This programmable ignition timing module used in conjunction with our high energy ignition module KC-5247 allows you to program timing of engines with points? Hall effect or reluctor distributors well as many other features."

DISTRIBUTOR?? RB's don't have distributors :confused:

[pshrdeta]

i see what youre saying

it controls the ignition through the distributer

hard to do when you have multi point coils

[Sydneykid]

Nice write up! Have already decided on just this approach for the missus 4 door auto Skyline (although she doesn't know she's getting one yet!).

For the sake of being pedantic, extrapolation is estimating a value outside the range of measured points, interpolation is estimating a value that sits between two measured points.  Gav

Thanks Gav, post suitably amended:cheers:

[CEF11E]

Distributor? whats that??? j/k..

I havent seen one of those for a long time. :0

[Sydneykid]

The SITC arrived today in good condition and I will be fitting it tonight. Looks pretty simple, and it fits in the glove box OK with the IEBC and the DFA.

This is the SITC, I replaced the standard plugs on the cables that the Stagea needs;

Red = +12 V parallel connection to Pin 67

Black = -12V parallel connection to Pin 25

Blue = Pin 46 (CAS 0 degrees)

White = Pin 44 & 45 (CAS 120 degrees)

Peach = to the wires that used to go to Pin 44 & 45

Light Blue = to the wire that used ot go to Pin 46

As you can see from the picture I have used female connectors on blue and white and male connectors on peach and light blue. I also made up some Y connections so that I can simply unplug the SITC and replug the standard wires back together.

I like the nifty buttons on the SITC that pop out (like 1, 3, 5) so you can adjust them and then they push back in (like 2, 4) so you can't accidently change the settings.

Edited July 13, 2006 by Sydneykid

[emanuelt]

How much should a second hand SITC cost?

I'm thinking of getting one to help my remote start, when the car is cold remote start will not start up properly, but when cold and I use the key its fine. If the engine is warm it starts fine with remote start?

[emanuelt]

SK do you have any pics of the Stagea ECU and any more installation pics.

Thanks

[Sydneykid]

How much should a second hand SITC cost?

The one I got was $210, they are often on Ebay for $US199.

I'm thinking of getting one to help my remote start, when the car is cold remote start will not start up properly, but when cold and I use the key its fine. If the engine is warm it starts fine with remote start?

Doesn't sound like an ignition problem, more like a fuel problem.

SK do you have any pics of the Stagea ECU and any more installation pics.

We are racing at Sandown this weekend, I will post up the install and wiring pictures when I get back to my home computer.

[Sydneykid]

Finished the install of the SITC during the week, I put it in the glove box with the IEBC and the DFA. It already had some velcro on the bottom, so I just stuck some on top of the IEBC to hold it in place.

It's a tight fit, not a lot of room left, but I can still fit my gloves in there

I wired it into the harness using the bullet plugs and I made sure I put the male and female plugs on the standard wiring. That way I can remove the SITC (and the IEBC and DFA) and just plug the standard wires back together.

The extra wires meant I couldn't get the standard plastic cover to fit into the clips on the ECU plug. So I used a pair of cable ties to hold it in place and protect the back of the ECU plug.

Well that's it for the install, now for some testing. I warmed the engine up and checked the timing (timing light) with the SITC set on zero for all rpm ranges.

It was as I set it (15 degrees BTDC) when I changed the timing belt and the adj camshaft pulley. So I adjusted the 800 rpm knob to 10 degrees advanced, and checked it with the timing light, bingo 25 degrees BTDC. Then I adjusted the 800 rpm knob to 10 degrees retarded and checked it with the timing light. Bingo again, 5 degrees BTDC. Since the 800 rpm knob is working perfectly, I think it is pretty safe to assume that the other 4 will be too.

As soon as I fit the exhaust I will stick it on the dyno and give it a tune. I can lean it off some more with the DFA and then retard the igntion timing with the SITC if it starts to ping (pre-ignite). Not quite as accurately (it has only 5 load points) as I could with Power FC, but I am sure it will be close enough to satisfy my power requirements and help meet my power target of 200 4wkw.

Edited July 13, 2006 by Sydneykid

[GTRgeoff]

Oh hello Sir, do you have FCC approval for all that extra electronics emmissions and the substantial radiation threat you pose to passing aircraft?????