timing off (pops, etc) - ideas on this map? (pics)

paulc · Post by **paulc** » Wed Aug 19, 2009 11:53 pm

so - i transposed the 2d map above in the distributor curve as follows...

RPM IGN-ADV LOAD
500 10 1
600 10
700 10
800 10
900 10
1000 10 2
1100 11
1200 12
1300 14
1400 16
1500 16 3
1600 16
1700 17
1800 18
1900 19
2000 20 4
2100 24
2200 26
2300 28
2400 30 5
2500 31
2600 32
2700 32 6
2800 32
2900 32
3000 32
3100 33 7
3200 33
3300 33
3400 33
3500 33
3600 33
3700 33
3800 33
3900 33
4000 33 8
4100 32
4200 32
4300 32
4400 32
4500 32
4600 30
4700 30
4800 30 9
4900 30
5000 30
5100 28
5200 28
5300 28
5400 28
5500 28 10

----------------------

into a 3d MJ MAP (config) file (although it's still only 2d in values) as follows...

LOAD BIN 10 20 30 40 50 60 70 80 90 103
RPM BIN 500 1000 1500 2000 2400 2700 3100 4000 4800 5500

advance0 10 10 16 20 30 32 33 33 30 28
advance1 10 10 16 20 30 32 33 33 30 28
advance2 10 10 16 20 30 32 33 33 30 28
advance3 10 10 16 20 30 32 33 33 30 28
advance4 10 10 16 20 30 32 33 33 30 28
advance5 10 10 16 20 30 32 33 33 30 28
advance6 10 10 16 20 30 32 33 33 30 28
advance7 10 10 16 20 30 32 33 33 30 28
advance8 10 10 16 20 30 32 33 33 30 28
advance9 10 10 16 20 30 32 33 33 30 28

Am i doing this right?

Broke4speed · Post by **Broke4speed** » Thu Aug 20, 2009 12:59 am

paulc wrote:brent.... fantastic idea!!

requirement 1) know the stock ignition curve

just out of curiosity - what would happen if i made a 2d map based on that curve? would it not perform like stock?

Broke4speed - this is car #14, i know it's not the carbs. you can hear/feel it.

I'm not trying to propose that you don't know what you're doing, my apologies. In my own experiences, a hopped-up distributor-based ignition system jets differently than a DIS one. Not a huge change, but enough to count.

NITROPIXIE · Post by **NITROPIXIE** » Thu Aug 20, 2009 9:12 am

I don't understand why you have reduced values of advance at the higher revs ie from 4000 onwards?? Is it a kind of rev limiter you have built into the values.

From my understanding of timing, higher rpm requires higher values of advance, because the air fuel mixture takes a certain amount of time from ignition to providing the engine with power.

Concerning the load part of the system, how do you have the vacuum system setup with split carbs to the MAP sensor??

paulc · Post by **paulc** » Thu Aug 20, 2009 3:55 pm

i have dual carbs, and each intake manifold (4) is tapped with a MAP bung and then routed to a mini-pulse-reducing reservoir (like the install guide suggests).

as far as reducing timing goes - i won't beat around the bush - i don't know what i am doing.

i looked at other folks maps, and guessed. i haven't had a chance to run this 2d/3d map yet, but i'll up the higher RPM ignition advance like this:

LOAD BIN 10 20 30 40 50 60 70 80 90 103
RPM BIN 500 1000 1500 2000 2400 2700 3100 4000 4800 5500

advance0 10 10 16 20 30 32 33 35 36 36
advance1 10 10 16 20 30 32 33 35 36 36
advance2 10 10 16 20 30 32 33 35 36 36
advance3 10 10 16 20 30 32 33 35 36 36
advance4 10 10 16 20 30 32 33 35 36 36
advance5 10 10 16 20 30 32 33 35 36 36
advance6 10 10 16 20 30 32 33 35 36 36
advance7 10 10 16 20 30 32 33 35 36 36
advance8 10 10 16 20 30 32 33 35 36 36
advance9 10 10 16 20 30 32 33 35 36 36

I'm guessing from here - it's seat-of-the-pants tuning, right?

DannyP · Post by **DannyP** » Thu Aug 20, 2009 7:46 pm

Nitro, re high speed retard: my engine builder told me type 1 engines of very high state of tune like 1 degree of retard for every 250 rpms above 4800. You simply can't do that with a distributor, as advance is usually all in by 3000 or so and flat after that. My motor pulls like a freight train to 6500, and would pull higher if I wanted to beat it to death! Valvetrain is good to 7500, but I like my main bearings.

Paul, I am not sure that a type 4 will require any retard or if max advance should be 33 degrees. Most aircooled go 28-30 max. What is CR, cam, jetting, fuel etc. Is it pinging?

Sputtering to me sounds like too much advance, as long as you are 100% sure fuel is correct. Is your trigger wheel indexed properly, not trying to insult you, but are you sure?

Also a possibility that the crank sensor bracket is resonating, which causes the EDIS to get confused. Also could be non-resistor plugs causing EMF and confusing the EDIS.

My engine was jetted on a dyno with a distributor(009). I haven't changed the jetting since Megajolt, it's fine as I have done some full throttle shut downs to look at the plugs.

DannyP · Post by **DannyP** » Thu Aug 20, 2009 7:49 pm

Paul, do you have a picture of your crank sensor and bracket?

Is it as solid as this? Notice the RAT stamp in the engine case, thanks Jake!

NITROPIXIE · Post by **NITROPIXIE** » Thu Aug 20, 2009 10:43 pm

Paulc - it very much can be seat of the pants tuning with a bit of time and patience. Just for information, as the 500 rpm and 1000 rpm bins all have the same advance you can effectively get rid of the 500 rpm column and the same with the 5500 rpm column, unless you plan on putting different loads in later.

Just to keep in mind, on most engines you can cause damage having too much advance at higher loads and higher rpms. So it would be safer to be more conservative with advance and advance the timing a little each time you go to tune it until the best results are achieved and don't go beyond this point.

Are you 100% that there aren't any air leaks with the vacuum setup?? it looks good and you seem to have the right kind of setup but would be nice to see some greater vacuum especially at idle so that you get a greater variation of load range.

Dannyp - I do have very limited experience with flat engines to be honest and megajolt is able to give a greater flexibilty of angles of advance never before seen from a dizzy. Hopeful that will change though at some point with future projects (rubbing of hands).

paulc · Post by **paulc** » Thu Aug 20, 2009 11:41 pm

thanks Danny - i just redid my VR sensor bracket (wasn't happy with the first one i made).

so - just to clarify NITROPIXIE -

is my advance too much? Danny is running 36 degrees on his setup (similar to mine)

DannyP · Post by **DannyP** » Fri Aug 21, 2009 1:58 am

But NOT at full load! That is only at 0-10% throttle position, which is cruise or deceleration. At full load, it is less, 32 degrees. Why I can get away with it specifically, I don't know. It has to do with many factors, dynamic compression, valve timing, combustion chamber shape, etc. Like I said, most flat engines can't use more than 30 degrees at full load. If I were you, I would reduce max advance to 28 at full load, and verify it with a simple timing light. Then drive that combo, and see how much better it runs. You do have timing marks on there, maybe a degree wheel? Just so you know, that is not the most current version of my map. I am up to version 17, and after I add the temp compensation, it will go a few versions higher than that.

paulc · Post by **paulc** » Fri Aug 21, 2009 3:18 am

thanks for the heads-up danny. i've backed it down to this:

mapBins=10,20,30,40,50,60,70,80,90,103
rpmBins=5,10,15,20,24,27,31,40,48,55
advance0 10 10 16 20 26 27 28 28 28 28
advance1 10 10 16 20 26 27 28 28 28 28
advance2 10 10 16 20 26 27 28 28 28 28
advance3 10 10 16 20 26 27 28 28 28 28
advance4 10 10 16 20 26 27 28 28 28 28
advance5 10 10 16 20 26 27 28 28 28 28
advance6 10 10 16 20 26 27 28 28 28 28
advance7 10 10 16 20 26 27 28 28 28 28
advance8 10 10 16 20 26 27 28 28 28 28
advance9 10 10 16 20 26 27 28 28 28 28

gunno go give it a try in a few minutes.

paulc · Post by **paulc** » Fri Aug 21, 2009 4:17 am

better, but i now feel like i need to adjust for load.

less load = higher KPa = less aggressive advance curve

more load = lower KPa = more aggressive advance curve

is that the just of it?

it's sort of hard to drive / watch / adjust / feel

Going to try this one out.

mapBins=10,20,30,40,50,60,70,80,90,103
rpmBins=5,10,15,20,24,27,31,40,48,55
advance0=8,10,15,23,27,29,30,30,30,28
advance1=8,11,15,23,27,29,30,30,30,28
advance2=8,12,15,23,26,28,29,29,28,28
advance3=9,12,16,22,26,27,28,28,28,27
advance4=9,13,16,22,26,27,28,28,27,26
advance5=9,13,16,22,26,27,28,28,27,25
advance6=9,14,17,22,26,27,28,28,27,24
advance7=9,15,18,21,26,27,28,28,27,23
advance8=9,15,18,20,26,27,28,28,27,22
advance9=9,15,19,20,24,26,28,28,27,20

paulc · Post by **paulc** » Fri Aug 21, 2009 4:32 am

oh ya - this is what I'm trying to tune

TwoSheds · Post by **TwoSheds** » Fri Aug 21, 2009 5:54 am

paulc wrote:oh ya - this is what I'm trying to tune

YEAH BABY!

NITROPIXIE · Post by **NITROPIXIE** » Fri Aug 21, 2009 6:54 am

I want one!!!!! Really does look nice, i wouldn't mind driving it around to sort out the timing, he he. Get that phot into the site banner http://www.autosportlabs.org/viewtopic.php?t=2469

DannyP · Post by **DannyP** » Fri Aug 21, 2009 1:22 pm

Paul, you've got it backwards. High load, select max advance minus a degree or two for ping(detonation) safety.

Less load you can have more advance than your full load max, can help with throttle response and mileage, if you care. Be careful, very easy to damage an aircooled motor with too much advance. Although it is easy to hear, sounds like a bunch of marbles in a large tin can in a paint shaker!

By the way, I see some light under that car, can you lower it a little more?