I've been reading the megasquirt forums learning about controlling timing with it, but thought it would be nice to be able to re-create the stock spark maps on the megasquirt for the very first start-up. So, If anyone has the HPTuners software on their car, would you mind postnig a screen shot of the timing maps. I know that as the map sensor increases, the computer begins to take timing out, retarding it one or two degrees. But as for what is normal, is what i'm trying to learn. Do the spark usually occur at 8 degrees BTDC like my friends mr2... ? You know what I mean? So, any spark timing maps would be useful. Thanks.
THANK YOU SHIFTED! That will help a bunch when I go to build the spark maps. Do you know what those numbers are in reference from? are the degrees before top dead center, or after top dead center?
I would think it would make sense the they are degrees before top dead center since they go down as kPa increases, and increase as rpm goes up.
Oh, also, I assume this is on your 2.4 right?
Just so I understand this right, if we look at the high octane map, then at 6000 rpm, and 100 kpa, the 22 is 22 degrees before top dead center or after top dead center.
I was just reading a page, that I believe explained the idea behind the spark maps, and it lead me to believe that those numbers are degree's before top dead center, and the negative numbers are actually degrees after top dead center.
One part of the article i read said, "As engine RPM increases there is less time to be able to fire the cylinder. The parts are moving faster so you must get the spark in there sooner, but not too soon that it will cause detonation or engine damage."
This leads me to think that since your numbers are increasing in numerical value, then that number most likely means degrees before top dead center. This accomplises the "get the spark in there sooner" as rpm increases.
Ok, great, now I at least have a good starting point. Thank you shifted.
Yeah, as I wrote above, advance is before TDC. The "modifier" tables I posted subtract that amount from the base table to produce the actual spark advance.
So, for example...
If the engine is using the High Octane table, at 100KPA and 2400 RPM, the advance is 18 degrees base. The IAT Temp is 160 degrees so that removes 1 degree from the advance, down to 17, ECT is 113 (not quite warmed up yet), so that adds 5 degrees, up to 22 degrees advance.
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Oh, ya, that was an incident of i started to write my post before your second post with the clairification. Opps. That's what i get for being too fast.
Yup, I got it now. Thanks.
Well, this isn't HPTuners, and it isn't from a 2.4. But it is from stock tables for a 94 2.2 which have been modified to work with a stock 94 spec 2.2 running 7.7 psi, 87 octane fuel, and non intercooled.
Yes, as stated before, this is degrees before TDC. This is the main spark table. 8 psi is roughly 150 kPa. Above those values I cannot promise the spark table is correct, but it's closer than nothing.
Next picture:
These values are added to the main spark values when PE mode is active. Ex. at 3200 RPM and 150 kPa in PE the spark is combined as 3.5 + 1.4 = 6.9 deg BTDC. Third table:
Third picture:
These values are also added to the main spark table. This table is for boost, so the MAP values are for pressures above 100 kPa. Ex. at 3200 RPM and 150 kPa, in PE mode, and with intake air temps at 80 deg C, total timing is 3.5 + 1.4 + 17.6 = 22.5 deg BTDC.
My ecm uses a different table to add more spark advance if better fuel is detected. You might want to add a few degrees of advance (about 2 or 3 to start) if you're using higher octane fuel. But you should not add spark advance if you are running higher compression since the air:fuel mix will burn faster.
Also note that I am not running EGR. If you plan to use EGR you will have to add additional spark advance to correct for the intake charge dilution.
Different tuning software can display corrections differently, and different PCM/ECM calibrations can use corrections differently. In this software and for my ecm, the correction tables will display negative values if the amount is being subtracted. Hopefully this explains why you may hear that corrections are subtracted from one person and added by another.
Keep in mind that the 2200 and 2.4 have different design combustion chambers which will alter the timing values. These engines have more efficient chambers and should require less advance than a 2.2 OHV. For example, the 2.4 appears to require 25 degrees advance at 3200 RPM and 60 kPa with the engine warm and IAT below 80 deg. The 2.2 OHV advance (mostly stock below 100 kPa) is adjusted for 38 deg BTDC.
I can post or email completely stock GM spark maps for the 2.2 if needed.
Oh, and BTW, I just checked mileage today and this car is getting 29 mpg, even with me driving. So the timing tables can't be too far off.
-->Slow
Thank you a lot slowolej. That should help a lot when I go turbo. I've been curious what the map would look like above 100kPa. Also, are you getting those from megasquirt? if not, what are you using to turn that car? And will it work on a 95 2.2? I know you've been the go to guy for these obd1 chips/eeproms. But, i'm not even sure how to tell if i have an obd1 computer. The scan port is an odb2 style, but obd2 scanners can't read it, so i guess it's obd1, just with an obd2 scan port.
These maps are from the 1227749 turbo Sunbird ecm I'm using instead of the factory ecm. This ecm can run the engine in your car, but it won't work in cars with an electronically controlled auto trans. The problem occurs with gauges and other extras. The 7749 can't output more than the vehicle speed for gauges so people with 96+ cars usually don't choose this ecm.
The 95 ECM in your car is really a bastard child. It's not really OBDII but it has got more than OBDI capabilities and power. You can't use a universal scantool to retrieve data from it, however, you can probably switch to another ecm without a problem in the eyes of the law. The question becomes whether or not you want to change your dash and gauges (or if you even have to) or try to work with the stock control module.
hth
-->Slow
slowolej, if you could email me the stock spark tables for the 2.2 it would be appreciated.
can email them to kdjhome@telus.net
wow, i'm already liking the effect that this HPTuners stuff is having on discussion around here... lots of new and informative stuff!
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Quote:
slowolej, if you could email me the stock spark tables for the 2.2 it would be appreciated.
Yep. Give me a day or two to get it transferred from the laptop.
-->Slow
would the 1227749 turbo Sunbird ecm not have a serial data signal for the cluster? I have noticed that GM took all the cluster information, and put it in a digital. serial signal, and send it to the cluster to be decoded there. Kinda sucks if you want to switch. but eh.. I'll probably just go with megasquirt. it's got the 2.5 bar which is what i'll be approaching. Even with this sunbird ecu, it's set for what looked like up to 2 bar, not 2.5.
Since I can do full fuel and spark control on the megasquirt, i'm leaning towards that heavily.
Quote:
would the 1227749 turbo Sunbird ecm not have a serial data signal for the cluster?
The older car clusters are analog. Separate wire direct from sensor for temp, fuel, and oil pressure. Tach reads off the coil signal. Speedometer is driven by ecm. Boost shares line for MAP sensor. Digital information in the J came about in '95.
Quote:
Even with this sunbird ecu, it's set for what looked like up to 2 bar, not 2.5.
With a 3 BAR MAP , GM # 12223861AC Delco # 213-1562, and a small code patch it works to almost 30 psi. I'm at 17 with the 3 BAR sensor.
OE 7749 ECM has some good stuff. Boost control, knock retard, additional fueling during knock, even emergency boost reduction if knock can't be stopped fast enough. And it's $50 or so at a junkyard, plus you can probably find a spare easily if something goes wrong.
But, MS has a bunch of support, is small, and is probably easier to tune.
Benefits either way, I guess.
-->Slow
slowolej wrote:Quote:
would the 1227749 turbo Sunbird ecm not have a serial data signal for the cluster?
The older car clusters are analog. Separate wire direct from sensor for temp, fuel, and oil pressure. Tach reads off the coil signal. Speedometer is driven by ecm. Boost shares line for MAP sensor. Digital information in the J came about in '95.
Quote:
Even with this sunbird ecu, it's set for what looked like up to 2 bar, not 2.5.
With a 3 BAR MAP , GM # 12223861AC Delco # 213-1562, and a small code patch it works to almost 30 psi. I'm at 17 with the 3 BAR sensor.
OE 7749 ECM has some good stuff. Boost control, knock retard, additional fueling during knock, even emergency boost reduction if knock can't be stopped fast enough. And it's $50 or so at a junkyard, plus you can probably find a spare easily if something goes wrong.
But, MS has a bunch of support, is small, and is probably easier to tune.
Benefits either way, I guess.
-->Slow
for the money, in Loki's situation, I'd say MS.... especially since 95 doesn't require a computer hookup to pass inspection, and only has to pass a sniffer test.... because for the money of hptuners and an ecu swap, you can most likely configure the MS to run fuel/spark/boost control and have it come out even... Anything newer than 95 in an emissions-strict state though, def. HPTuners as the number one option.
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oops!! there i go, not paying attention again!
Arrival Blue 04 LS Sport
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