Ignition Mapping

[petert 554]

When I ran in my new engine on the dyno, I thought I'd given it a conservative 25 degrees of maximum advance at full load, from 3000 to 7500 to produce 123kW at the wheels. It has 11.8:1 CR, runs on 100 ron fuel and has CDI ignition. Yesterday I did some very brief experimenting with ignition advance. Well respected tuners had suggested I should be running 30 degrees. I didn't think it would need that much.

 

So I did a few power runs. For the first run (red) I reset the full load points all to 28 degrees. This yeilded approx 117kW. Down nearly 6kW from the run-in session. Second run (blue) gave an almost identical result with 30 degrees. The third run (green) was 30 degrees again just to make sure. So then I put the original mapping back in (pink) which returned the power to what you'd call acceptable error based on the original results. A gasped a sigh of relief but the brain cogs really started ticking.

 

Then it was suggested I hadn't set up the trigger position correctly and it was probably running 30 degrees anyway. So then I found TDC and started puting some marks on the harmonic balancer. I took great care to make sure I accurately found TDC and 25 deg. BTDC. Just to make sure I wasn't fooling myself, I put two extra marks on the inner and outer, to check for slip. A check with the timing light revealed it slipped 10 degrees as soon as it started! So that was useless.

 

I already had a mark on the flywheel at TDC, so I then added another four teeth later, 24 degrees BTDC. Those Motronic teeth make fantastic timing marks. I screwed on my pointer which sits in the hole near thge starter motor and doubled checked the timing at TDC and at 24 degrees. All this revealed I was indeed out, by one degree RETARDED. So when I thought I had 25, it was actually 24 degrees! A quick adjustment with the software fixed that.

 

So what does all this mean? Well I've just given you some valuable information if you have an engine similar to mine. The full load advance curve goes from 14 to 24 degrees, meaning it has a very efficient burn, not needing the extra time to start the fire. A standard D6C ceratainly does not have a flat curve from 3000 onwards, but does need 30 degrees maximum. If you got something in between, say 11:1+, I'd suggest you start experimenting with 26-28 degrees maximum. I need to go back to the dyno and experiment at every 500rpm to make sure 24 deg. is perfect at each interval. I know from other modified Mi16 engines that a degree here or there makes a significant difference to mid range torque.

 

It's also important to remember I'm talking about maximum full load advance. More will need to be added for cruise, as the load decreases, to improve fuel economy and part throttle response.

 

(yes, the AFR's are like a roller coaster and need fixing too)

Edited May 20, 2007 by petert

[Sandy 189]

I tell you what, it's been amusing me lately how similar "different" 16v engines can be on ignition. Nothing like the variations 8v's seem to end up with. My H22A7 is apparently 11:1 (Factory) and ran from 12-28 degrees (calibrated trigger wheel) at full load (maximum 28 degrees at 7800 rpm). Pretty close eh?!

[midnight motorsport 0]

When I ran in my new engine on the dyno, I thought I'd given it a conservative 25 degrees of maximum advance at full load, from 3000 to 7500 to produce 123kW at the wheels. It has 11.8:1 CR, runs on 100 ron fuel and has CDI ignition. Yesterday I did some very brief experimenting with ignition advance. Well respected tuners had suggested I should be running 30 degrees. I didn't think it would need that much.

 

So I did a few power runs. For the first run (red) I reset the full load points all to 28 degrees. This yeilded approx 117kW. Down nearly 6kW from the run-in session. Second run (blue) gave an almost identical result with 30 degrees. The third run (green) was 30 degrees again just to make sure. So then I put the original mapping back in (pink) which returned the power to what you'd call acceptable error based on the original results. A gasped a sigh of relief but the brain cogs really started ticking.

 

Then it was suggested I hadn't set up the trigger position correctly and it was probably running 30 degrees anyway. So then I found TDC and started puting some marks on the harmonic balancer. I took great care to make sure I accurately found TDC and 25 deg. BTDC. Just to make sure I wasn't fooling myself, I put two extra marks on the inner and outer, to check for slip. A check with the timing light revealed it slipped 10 degrees as soon as it started! So that was useless.

 

I already had a mark on the flywheel at TDC, so I then added another four teeth later, 24 degrees BTDC. Those Motronic teeth make fantastic timing marks. I screwed on my pointer which sits in the hole near thge starter motor and doubled checked the timing at TDC and at 24 degrees. All this revealed I was indeed out, by one degree RETARDED. So when I thought I had 25, it was actually 24 degrees! A quick adjustment with the software fixed that.

 

So what does all this mean? Well I've just given you some valuable information if you have an engine similar to mine. The full load advance curve goes from 14 to 24 degrees, meaning it has a very efficient burn, not needing the extra time to start the fire. A standard D6C ceratainly does not have a flat curve from 3000 onwards, but does need 30 degrees maximum. If you got something in between, say 11:1+, I'd suggest you start experimenting with 26-28 degrees maximum. I need to go back to the dyno and experiment at every 500rpm to make sure 24 deg. is perfect at each interval. I know from other modified Mi16 engines that a degree here or there makes a significant difference to mid range torque.

 

It's also important to remember I'm talking about maximum full load advance. More will need to be added for cruise, as the load decreases, to improve fuel economy and part throttle response.

 

(yes, the AFR's are like a roller coaster and need fixing too)

 

Hi peter, thanks for reading about my nurburgring trip, it was so much fun! !Everyone that went, said that my car, was the best out of all that went, that included 3 mk2 golfs ( 1= 20v turbo, 1= 2.9vr6, 1=16v) 2 vr6 mk3 golfs, 1= m3 bmw (stripped out, caged, etc etc..) I went around the outside of this about 2/3 around the track, after startin 30 after it biggrin.gif,

 

Anyway i think you catch my drift the car went well!!

 

But going back to your post here, when i got the engine set up and run in, we set the adv at a what we thought was a tame 32 deg,

Now like i was saying i think that my carb and dizzy set up are a fairly limiting factor in this car, as, the car felt good on power, and was not pinking or anything so on the way over ther when messing about with jets etc, i knocked the timing forward a bit, and boy did the car feel like a load of crap in the high rev range!! But of course if felt amazing on the pick up, ie bang the throttle and light up the tyres smile.gif

So we knocked the timing back a bit (forgot my timing light so just guessed a few degrees back again), and it felt good,

But then somthing wierd happened, the car suddenly died on the way home? The funny thing was the rev counter went dead too, so i knew it was something to do with the primary ign, so changed ign amp, (no change) so changed dizzy, sweet!! (and yes i did have one of everything with me on that trip!!! Biggrin.gif i was getting home one way or another!

But as i couldnt time it up i just guessed it, that car went really bad, so kept backing of the adv, and now i sware the car is going better that before?

So i will check the adv over the next few days and report my findings here,

 

But like i say i really want to change this set up now, as i feel that i could get so much more from this engine with mapped fuel and ign, as you just cant get a good balance on the ign timing, my car felt like it wanted more advance down low and less up top, infact i know thats what it wanted, and messing with bob wieghts and springs is too 1970s for me, so i think im going to shelve the pug untill ive saved up for a set of throttle bodies and ecu,

 

If anyone has or knows of any for sale please let me know,

 

And i will report my ign findings asap,

 

Cheers , jay

 

Oh yes just thought id add,

 

Maybe thats part of the reason that in 1st, 2nd, 3rd, 4th, it would pull like a train up to 7500-8000 ish ohmy.gif

But in 5th and 6th it reallt tailed off at 6000-7000? And since doing that other dizzy thing it seems a bit better? Maybe it still has too much full load advance? And cant pull in the top gears when its fully loaded?

 

 

Right! Im off to check timing smile.gif

And find a 3d ecu and bodies!!! Biggrin.gif

 

Any ideas?

 

Jay

 

(edit: ALL CAPS POST changed to lowercase)

Edited May 21, 2007 by jackherer

[Sam 4]

[midnight motorsport 0]

 

 

KISS MY *SS (*= THERE IT IS RIGHT NEXT TO CAPS LOCK) only joking!!

 

Yeah sorry, i did think that after id writen it all!! but i was dammed if i was going to write it all again!!

 

cheers,

 

jay

[petert 554]

These were the three full load ignition curves, adjusted 1 degree.

[midnight motorsport 0]

Hi peter, thanks for reading about my nurburgring trip, it was so much fun! !Everyone that went, said that my car, was the best out of all that went, that included 3 mk2 golfs ( 1= 20v turbo, 1= 2.9vr6, 1=16v) 2 vr6 mk3 golfs, 1= m3 bmw (stripped out, caged, etc etc..) I went around the outside of this about 2/3 around the track, after startin 30 after it biggrin.gif,

 

Anyway i think you catch my drift the car went well!!

 

But going back to your post here, when i got the engine set up and run in, we set the adv at a what we thought was a tame 32 deg,

Now like i was saying i think that my carb and dizzy set up are a fairly limiting factor in this car, as, the car felt good on power, and was not pinking or anything so on the way over ther when messing about with jets etc, i knocked the timing forward a bit, and boy did the car feel like a load of crap in the high rev range!! But of course if felt amazing on the pick up, ie bang the throttle and light up the tyres smile.gif

So we knocked the timing back a bit (forgot my timing light so just guessed a few degrees back again), and it felt good,

But then somthing wierd happened, the car suddenly died on the way home? The funny thing was the rev counter went dead too, so i knew it was something to do with the primary ign, so changed ign amp, (no change) so changed dizzy, sweet!! (and yes i did have one of everything with me on that trip!!! Biggrin.gif i was getting home one way or another!

But as i couldnt time it up i just guessed it, that car went really bad, so kept backing of the adv, and now i sware the car is going better that before?

So i will check the adv over the next few days and report my findings here,

 

But like i say i really want to change this set up now, as i feel that i could get so much more from this engine with mapped fuel and ign, as you just cant get a good balance on the ign timing, my car felt like it wanted more advance down low and less up top, infact i know thats what it wanted, and messing with bob wieghts and springs is too 1970s for me, so i think im going to shelve the pug untill ive saved up for a set of throttle bodies and ecu,

 

If anyone has or knows of any for sale please let me know,

 

And i will report my ign findings asap,

 

Cheers , jay

 

Oh yes just thought id add,

 

Maybe thats part of the reason that in 1st, 2nd, 3rd, 4th, it would pull like a train up to 7500-8000 ish ohmy.gif

But in 5th and 6th it reallt tailed off at 6000-7000? And since doing that other dizzy thing it seems a bit better? Maybe it still has too much full load advance? And cant pull in the top gears when its fully loaded?

Right! Im off to check timing smile.gif

And find a 3d ecu and bodies!!! Biggrin.gif

 

Any ideas?

 

Jay

 

(edit: ALL CAPS POST changed to lowercase)

 

 

just to say thanks too jackherer, for moding the post,

 

hope i havent offended anyone,

 

sam i really was only joking, thanks, guys,

 

jay

[midnight motorsport 0]

These were the three full load ignition curves, adjusted 1 degree.

 

Peter, What was the best final adv and power combination? i assume that your engine was a 2L one? although being that they both run the same cylinder heads and c.r, that the advance will be similar? also what engine management do you run? as i am looking to get some in the near future,

 

cheers

 

jay

[jackherer 543]

just to say thanks too jackherer, for moding the post,

 

no problem

 

I used word to do it btw, I pasted the text into a new document then selected change case from the format menu.

[midnight motorsport 0]

no problem

 

I used word to do it btw, I pasted the text into a new document then selected change case from the format menu.

 

 

cool, cheers mate

 

hopefully i wont need it, as i will try to type it properly from now on