BETTER IMAGE ADDED....


The reason I ask is on the rollers yesterday I had slight detonation above 5,000rpm (ish). The run was then aborted.

Fuelling was OK and the operator recommended that the timing needed retarding.

looking at the above map I figure that the area around 5,000rpm - 6,400rpm (bottom center of the map), is the region that needs retarding.

So would I be correct in thinking that reducing these figures for example by 5 degree's and making closure to TDC would be the right thing to do ?

Or would it be better to adjust the timing correction map (which at present I am assuming is mapped on the same axis).


P.S ECU Code was replaced with a similar map that had the same timing/fuelling parameters but target boost was dropped by 2psi. This gave no detonation and a figure of 255BHP.
With the extra 2psi the BHP was still rising (prior to the abortion), but the torque figure had peaked 20ft/lb more. At 5,100rpm. So my aim is to maintain that torque but get rid of the detonation that occurred above that RPM point.

[Edited by Scott.T - 9/1/2002 11:52:28 AM]

 

More advance (ie bigger numbers BTDC) at higher RPM. Less in the midrange to control det. More advance for the lower airflows and lower engine speeds. So there is a dip in the middle. A lot carry on 6000 RPM timing up to the top as some ECUs do not knock correct high up. If you are filling out the boost curve at the top in particular you may need to pull it out a lot compared to a tapering boost curve - because of extra boost (increased dynamic compression ratio), intake temperature and therefore in-cyl temp. Suggest adjusting the base maps rather than correction maps to get appropriate timing. Provoke it towards detonation in the nastiest conditions you can conjure up and retard or correct fuelling to get it det free. Then pull out your safety margin on top of this - this will depend on the quality of knock correction on your car.

[Edited by john banks - 9/1/2002 2:17:45 PM]

 

Sorry John, couldn't really get my head round your answer.

On the map below, if Det was occurring starting at 5,600rpm on the rolling road. Would you reduce the figures in Area 'A' or Area 'B' (or have I got it completely wrong and I need to increase the figures).



This is taken from a Pre96 Prodrive Map, which has slightly higher figures than the Standard Pre96 UK Map.



[Edited by Scott.T - 9/1/2002 3:20:51 PM]

 

FYI - Here's my Ignition & Fuel Maps - Sorry haven't had a chance to change orientation & scales - which are completely **** about face!





Chris


[Edited by Chris.Palmer - 9/2/2002 9:47:54 AM]

 

John,

Wise words to all.

I edit graphically - edit image - blow image - read image - display read image graphically (see previous above)& use binary file comparisons at each stage too - Just to prevent any really silly mistakes.


[Edited by Chris.Palmer - 9/2/2002 10:52:59 AM]

 

I'm trying to understand the timing Map from an MY94 upgraded ECU and need a few rule of thumbs, just so I can understnad what it's giving me.

I have a load axis and an Rpm Axis, but am wondering if they are shown on the 3D graph the correct way round.

As load/rpm increase should the Deg BTDC be figure be increasing or decreasing.

At no load and any Rpm (i.e throttle lift off) should the Deg BTDC be a large or a small figure.

The map below shows the item in question, although I think the load scale may be from the wrong part of the Map (Map address 84E0 - 84FF on the map seems to have better scaling).

 

Hmm, well more airflow means less advance needed
More speed means less advance needed
Higher inlet temps means less advance needed

More boost = more airflow, you get the idea

The 16x16 table should read Load from left to right
and rpm from top to bottom

Probably looking at retarding 1 deg per 5'C extra inlet temp over some baseline. And retarding 1 deg per psi boost over some baseline.

Obviously the baseline has to be know to start with, and you also don't know where you are on the map (yet) to know where to retard, so doing. At a guess you are in the top (rightmost) 25% of the map at 4500-5000 rpm, and retarding say the rightmost 6 values might be a good place to start.

Paul

 

O.K John. I've read your post a few times and also read an old Ford haynes manual which talks about changing settings if running unleaded.

If running unleaded the ignition is retarded by 2 Degree's, so if I need to retard to reduce/eliminate knock I must be right in thinking the values require reducing in the region where knock occurs.

Would I be right ?

I think the prodrive map was set by prodrive right on the limit of knock in order to get the best performance. The slight increase in boost I have given it must have pushed it beyond that limit, hence the knock and the reason I now have to retard it slightly.

 

Yes I agree. Drop the numbers to retard timing. You will soon know if you have gone the wrong way because it will get worse, but assuming the maps work similarly to other ECUs, then smaller numbers mean the ignition is retarded which will reduce your chance of det.

 

Scott, I think you have your igniion map **** about face somehow.

Load scale is backwards, should have more advance at lower loads.

Should like more like this:




Paul

[Edited by Pavlo - 9/1/2002 8:29:24 PM]

[Edited by Pavlo - 9/1/2002 8:53:52 PM]

 

Yep ya right there Paul.
I was using 84C0 instead of 84E0 for the load scaling, as per your original info emailed to me months back (Doh!)

I did think it a bit suspect....so this should now be correct....


It certainly highlights why Knock was occuring in that region as the PPP map has defo increased the advance in that area.

What Knock indicator are you getting, a 'Link' ? How much you paying for it as I may be interested in getting one too now.

P.S Nice bit of software, will have to get that installed.

 

OOoops....

Having actually read this thread - and with the issues over orientation & scales being "**** about face" etc - me now thinks my Ignigtion Timing Changes - are more by luck than design

Think I need to go away and look this again more carefully

Mind you - It didn't bang & ran well

PS - Graph here http://www.scoobynet.co.uk/bbs/threa...=115197&Page=8


[Edited by Chris.Palmer - 9/2/2002 9:50:41 AM]

 

Just be very careful you don't go and wholesale adjust the wrong row, or wrong part of a map (particularly with fuelling and ignition), the consequences are not pretty and it has been done before. Also really check any changes before committing data to the ECU and testing - make sure there are no $31 instead of $13. Sounds stupid. It isn't. A good way of ensuring you have not left your brain in the glovebox is to graph the maps with a known system or colour code them and any dodgy bits should stand out. Also actually look at every entry in the maps. It is easy for example to be using an editor changing swathes of data at a time and make mistakes. Sorry if this sounds patronising, not meant to be at all.

 

Chris,

You need to increase the length of the Scale on the BTDC, as it doesn't flatten like that really.

I think you need to start the scale at about 7 Degree's BTDC.

 

Hopefully this is a bit better to read now the scales are similar.

Certainly makes it easier to compare the differences between the two maps.





[Edited by Chris.Palmer - 9/2/2002 11:49:52 AM]

 

More like it.

Interesting the advance in the maxLoad/maxRPM.

I think the usage drops away from the corner, also at high rpm the VE would drop some, resulting in less air in the engine.

Next step is to get the ecu loggin sorted so you can see it move accross the map. I suspect it fell off the map in the middle, and wasn't able to retard the ignition further. Even though the PPP map has a larger load scale than the standard ($2f vs £2b I think).

Paul