3.0 Litre Update

Turn the key, drive the bloody thing...

Says him
I've tried turning the key ...........nothing Good job I've got homestart

Ive just realised what you were going on about earlier, I did my diagram wrong. Your's is right on that flywheel pic..

[stephendell]

I think my crazy math works now too!

In that case for the GTA it's back to 66 'theoretical' teeth in a 'full' flywheel @ 5.4545 degrees per tooth.

Does the sensor trigger on the leading edge or the trailing edge?

If the sensor triggered on the trailing edge of the large tooth (which would be teeth 20 and 21 in a sequence if the gap was machined out) then there is 10.9 degrees before the sensor would pick up the trailing edge of the next tooth (tooth 1 in the next sequence). Tooth 22 would then be considered the missing tooth.

If there are three repeat sequences at 120 degree intervals then the untriggered interval = 120 - 10.9 = 109.1 degrees

108 is pretty close to 109.1 so presumably that would still work?

Has anyone tried 109 degrees in the adaptronic?

Well even though a straight answer has not been forthcoming, a healthy discussion should always be encouraged. Dave, your diagram is slightly wrong. The pattern will be

101010101010101010101010101010101010101000111

Now if you look at a flywheel (and I do have a photo somewhere if I can track it down) you see that the teeth are evenly spaced and that if you ignore the joined and missing teeth, you get 66 even divisions.

The reason the Adaptronic software now includes a wizard for setting up the trigger is that I pestered Andy about this pattern and although the software can calculate in decimal places, the setup can't display it.

The sensor triggers on a FALLING edge, and will detect two missing teeth on a stock pattern, but will reset the counter too early on the next tooth I believe.

Theoretically (and I spent 3 years doing this sort of sh!t) you should be able to set it up with 66 teeth on crank, reset on two missing per period, angle of first tooth after reset os 60 degrees BTDC.

This does not work. Tried it

So what does work?

Well, knowing that bit of info, you can keep plugging in figures till the bigger runs, then check with a timing light and alter your trigger figure (the 60 degree bit) till it fires where you expect it to. This is I suspect where the 108 degree biut comes from. Why it's there I don't know, but I do know there's n 8 degree discrepancy when running an odd-fire engine....

However, as this has yet to be explained, I wonder if this only works at idle. And that any other given point in the ignition map, the figures may be off. So you may be running more advance/retard than you expect or than the software shows. Possibly why Tony's is now acting like it's more advanced when under boost

For example - peterg's config states that the engine has 6 cylinder and that there are 20 teeth per period. Now this is where the Adaptronic manual fails us slightly because what's not clear is whether it wants to know how many teeth there would be if they were all there (like a 36/1 means 35 teeth and one missing, each tooth equals 10 degrees), or now many ACTUAL teeth there are. So I would like to try peterg's config with the setting saying 22 teeth per period

I KNOW that telling it there's 66 teeth per CRANK (ie engine rev) and one missing per period works perfectly on a modified flywheel (and yes, once you've modded it, it'll never run again on a standar ECU but this was a moot point on a DeLorean with a donor 25 turbo engine and no ECU, or on Rob's Atmo and it's shiny new 3 litre 12v). The angle sit spits out are indeed 5.45 degrees per tooth which we know is correct.

I've e-mailed Andy to see if he can shed light on this but no reply as yet....

(ps am ex-curry house and two pints of cobra so typing at the speed of light and not making much sense probably...)

For example - peterg's config states that the engine has 6 cylinder and that there are 20 teeth per period. Now this is where the Adaptronic manual fails us slightly because what's not clear is whether it wants to know how many teeth there would be if they were all there (like a 36/1 means 35 teeth and one missing, each tooth equals 10 degrees), or now many ACTUAL teeth there are. So I would like to try peterg's config with the setting saying 22 teeth per period

)

The ecu doesnt want to know really HOW MANY teeth there are, more importantly at what angles they occur. (as I said previously, a japanese car can have 5 teeth - doesnt mean they are evenly spaced).

Which means you can't tell the ecu with the wizard that there are 22 teeth in the wizard (plus fat/gap), as we know 100% that each tooth on the Renault flywheel is 5.45 degrees apart, and if you work it out and tell there ecu there is 22 PLUS the missing/fat tooth, then this won't be this angle, and therefore is incorrect.

The 108 is NOTHING to do with the angle of TDC after the first reset point. If you look in the software in the wizard it asks for the 'angle BTDC of the first tooth after 'reset' - but we have set the software to look at periods only, not full crank rotations (period is the series of teeth), so the BTDC bit it irrelevant. The 108 is simply the point on the flywheel that missing tooth trigger occurs, nothing to do with reference to TDC on the engine.

Hurrah! An explanation.....admit it works so we can move on

Which means you can't tell the ecu with the wizard that there are 22 teeth in the wizard (plus fat/gap), as we know 100% that each tooth on the Renault flywheel is 5.45 degrees apart, and if you work it out and tell there ecu there is 22 PLUS the missing/fat tooth, then this won't be this angle, and therefore is incorrect.

{/quote]

But you can tell it there are 66 teeth on a crank when in reality there are 63 with 3 missing....

The 108 is NOTHING to do with the angle of TDC after the first reset point. If you look in the software in the wizard it asks for the 'angle BTDC of the first tooth after 'reset' - but we have set the software to look at periods only, not full crank rotations (period is the series of teeth), so the BTDC bit it irrelevant.

Sorry you've completely lost me here. The software NEEDS to know where the TDC point is in relation to the reset point, that's what the reset point is FOR! And you can measure the reference yourself on a bench! And yes I know we're only dealing with periods in peterg's config, but given that we've told the ECU it's got 6 cylinders, it'll work out for itself that these 20 teeth plus 2 missing or 22 incl 2 missing accounts for 120 degrees of crank rotation.

The 108 is simply the point on the flywheel that missing tooth trigger occurs, nothing to do with reference to TDC on the engine.

So it's a completely unitless measurement of nothing at all really.... is what you're saying. So why have it at all? Why not just have 66 teeth on the flywheel, Or for that matter, why not just read the ring gear teeth?

Maybe it's because the ECU needs to know at what point TDC occurs for either number one or each cylinder* ? And to do this, it needs to know where the reset point is in relation to TDC............

so we're back to the orignal quesiton: Where's the 108 figure come from?

*( for those who might want to learn here, having one missing tooth per engine rev gives the ECU enough information to know which cylinder is which - vital if you want to run coil packs/wasted spark. It does not need to know which cylinder is which if you run a distributor and batch fired injection - as we are here, so having a missing tooth for each cylinder pair is fine)

But you can tell it there are 66 teeth on a crank when in reality there are 63 with 3 missing....

No, you don't fill in the boxes in the setup window for the teeth that are missing, so you are not directly telling it how many teeth there are (well you are - only the 'real' ones)

Sorry you've completely lost me here. The software NEEDS to know where the TDC point is in relation to the reset point, that's what the reset point is FOR! And you can measure the reference yourself on a bench! And yes I know we're only dealing with periods in peterg's config, but given that we've told the ECU it's got 6 cylinders, it'll work out for itself that these 20 teeth plus 2 missing or 22 incl 2 missing accounts for 120 degrees of crank rotation.

Why? If I tell the ecu its 10 degrees before TDC or 50 degrees before TDC, you can just adjust the map to suit. Doesn't mean its not going to run - the evidence of that is it does run!

So it's a completely unitless measurement of nothing at all really.... is what you're saying. So why have it at all? Why not just have 66 teeth on the flywheel, Or for that matter, why not just read the ring gear teeth?

NO, its 108 degrees of teeth! Because, like Ive said numerous times, just because a flywheel can have 66 teeth, doesnt mean they are going to be at regular angles, so you can't just tell an ecu to look for 66 teeth and get on with it... The ecu is told there is 20 teeth per period, over a 108/9 degree section, = 5.45 degrees, which is correct. I can't explain it any simpler...

so we're back to the orignal quesiton: Where's the 108 figure come from?

We're not..

Please stop now my brain is melting - I do need to know one thing though - what happens when the car gets old and loses all its teeth?

Even I understand it now!! Please lets stop now....Martin,if its still not working for you feel free to keep on machining flywheels or PM David or something.
Personally I'm off to find out why bumble bees cant fly!

Proof of the 109.10 ,commonly known as the 108 theory ...................Trailing edge, measurements dont lie

http://www.cldesigns.co.uk/_vti_bin/GTA ... 09.10.jpeg

[stephendell]

All we need to do now is ask Tony or Peter to try changing the 108 data entry to 109 if possible and see if it still runs!

All we need to do now is ask Tony or Peter to try changing the 108 data entry to 109 if possible and see if it still runs!

It will, it will just advance the ignition table by 1 degree.

( for those who might want to learn here, having one missing tooth per engine rev gives the ECU enough information to know which cylinder is which - vital if you want to run coil packs/wasted spark. It does not need to know which cylinder is which if you run a distributor and batch fired injection - as we are here, so having a missing tooth for each cylinder pair is fine)

I "want to learn" but I cant see how you can positively identify a cylinder from the Crankshaft rotation - surely you can only narrow it down to one of two, given that each cyliner only fires once every two revolutions and you dont know which of those revolutions the engine is currently on. Dont you need a camshaft sensor in order to positively identify which particular cylinder is firing at any given time? I know its irrelevant to the GTA - just wanted to get all this stuff straight in my head.

Good question, I think on the GTA turbo, all injectors give a squirt of fuel on all cylinders irrespective of which one actually needs the fuel. In which case, the ECU does not need to know which pot is firing next, the distributer will just issue the spark to the next one. The other 5 will be cooled by the fuel and air will saok up the fuel droplets ready to be forced into the cylinder.