Ignition timing

I’m in the middle of going over my motor which is equiped with an Emerald ECU (to make sure everything is right)and I was wondering if anyone new what the maximum ignition timing (top of curve)would be for a UHPD K motor equiped with 1444 cams and enlarged valves.
Would it be 28,29,30deg…more?

Timing depends on CR, engine speed and load, I would expect to see no more than 32 degrees at 8000 with advance at around 10 degrees at 2000, and around 25 degrees at 5000, this is at full load (load site 15). The rest of the map will show varying degress of advance since when the cylinder is not completely filled the effective CR is lower and therefore the burn is slower, this necessitates a little more advance.

Send me your map and I will have a quick look over it for you. In the meantime there is a comprehensive article on engine management at here which may give some insight.


In the meantime there is a comprehensive article on engine management at > here > which may give some insight.

Wow - excellent article thanks Dave, I understood it all reading it through…not sure how much I will remember though!

Thank’s Dave,
I’ll try and down load the file as soon as possible, I’m still trying to get everything together to do it.
I was not given the software or the manual for the Emerald when I purchased the car (at least they left me the serial cable!).
I’ve downloaded the software from Emerald’s site as well as the operators manual, though it looks like there is a key code that has to be entered to unlock the software.

Once I get hold of it I’ll shoot it over, I’m interested to see what’s in there.

Emerald software should run freely on any machine. No unlock code.
Worst part is finding a laptop with a real serial port on it. Not too many around these days.
Works ok with USB/Serial converter, as long as you connect everything first before running the s/w.

Map has been sent Dave

Hi Dave,
do you know if there is a suggested/compatible knock sensor to plug into the Emerald?
I mean something cheap, which is read only (to be used with the Emerald datalogging software), simply to highlight the critical cells on the maps.


The Vauxhall C20LET is equipped with a knock sensor, this may be adaptable to the K series block. Whether the Emerald can accomodate it’s input I don’t know. Best speak to Karl.


Whats your view on knock sensors Dave?

My understanding is that knock sensors are tuned to the engine that a manufacturer fits them to as “knock” noise is different from one engine to another, pus as there is so much other noise coming from the engine it needs to be tuned to be listening for the appropriate “noise”.

To take this one step further a friend of mine who is an engine mapper for a manufacturer says that on a V8 quad cam chain driven engine he worked on, that had 4 knock sensors fitted to it (two on each bank, one between the front two cylinders and two betwen the rear two) they tuned the front knock sensor differently to the rear one as the front one had to deal with a lot more noise from the cam drive chain.


I’m not sure what you would gain from a knock sensor, I can see it’s value on a boosted engine or on an engine where the octane of the fuel cannot be guaranteed, but in this country where fuel quality is pretty much stable and the engine is calibrated reasonably there is not much reason to have one.

That said I’m sure that the response of the sensor will vary according to position and the material of the engine, however, I can hear pinking very clearly and recognisably on a variety of different engines… It may simply be down to some calibration of the sensors response.

The sensor is a simple Pizoelectric device which generates a voltage at the predetermined acoustic frequency, so I guess that specifying one would involve selecting or tuning one to react at the particualr frquency for the K.

Furrher probing has uncovered this quote…

The frequency of knocking (pinking) is approximately 15 KHz. As the response of the sensor is very fast an appropriate time scale must be set, in the case of the example waveform 0 - 500 ms and a 0 - 5 volt scale.

Knock sensors are available to purchase from several sources and they do not refer to any particular application data so from that I would presume that the frequency response is not engine specific.


Did you recieve that Emerald ECU file that I sent you?
I sent it to [email protected] , I hope that was the correct address.
Again if you know of anyone with a VHPD motor running 1444 cams, larger valves, some light port work, stock throttle bodies and a stage II sport exhaust (no cat) and they would be willing to share there current fuel and timing curves, I would really like to compare them to what I have at the moment.

I had a look at the map, there are a few small anomalies here and there which will affect idle and starting, the fuel numbers look small but then you may have larger injectors than standard, in which case only the shape of the fuel curve would be relavant, I did notice that the fuel went up between 8000 and 8500 which is of course mad…

I’ll see if I can root out a map for you later today.


Thank’s Dave,
It does idle very low and rough when first fired from cold, then the idle smooths and increases as it warms up.

I can’t figure out why Deman Motorsport decided to re-invent the wheel and go it on their own when there are so many great people such as yourself, with a massive well of knowledge willing to lend a helping hand to get these motors running right!
I can’t tell you how much I appreciate all your help!!