When do you see peak airflow here at altitude?

[mpdeneen]

I'm running an E316G (10lbs. boost) on a stock 1G MAS and a K&N filter. I'm running the stock ECU and a 3" exhaust. I'm seeing the following MMCD log:

Tim. TPS MAS RPM knock
37° 27.5% 301.9Hz 3063 1
34° 37.6% 415.1Hz 3063 1
30° 49.0% 509.5Hz 3094 1
29° 62.7% 585.0Hz 3188 0
28° 75.3% 647.9Hz 3188 0
27° 83.5% 704.5Hz 3250 0
25° 96.5% 786.3Hz 3313 0
24° 100.0% 842.9Hz 3375 0
24° 100.0% 861.7Hz 3438 0
25° 100.0% 886.9Hz 3500 0
25° 100.0% 912.1Hz 3563 0
25° 100.0% 930.9Hz 3625 0
25° 100.0% 962.4Hz 3719 0
24° 100.0% 993.8Hz 3750 0
24° 100.0% 1006.4Hz 3813 0
24° 100.0% 1044.1Hz 3875 0
24° 100.0% 1075.6Hz 3938 0
24° 100.0% 1100.8Hz 4031 0
24° 100.0% 1125.9Hz 4094 0
23° 100.0% 1151.1Hz 4156 1
22° 100.0% 1169.9Hz 4219 1
23° 100.0% 1214.0Hz 4313 0
24° 100.0% 1226.6Hz 4375 0
24° 100.0% 1264.3Hz 4438 0
24° 100.0% 1302.0Hz 4531 0
23° 100.0% 1314.6Hz 4594 0
23° 100.0% 1320.9Hz 4594 0
23° 100.0% 1358.6Hz 4656 2
22° 100.0% 1396.4Hz 4750 1
22° 100.0% 1402.7Hz 4813 1
23° 100.0% 1409.0Hz 4844 1
23° 100.0% 1427.8Hz 4938 0
24° 100.0% 1440.4Hz 4938 0
24° 99.6% 1446.7Hz 5031 0
24° 98.8% 1465.6Hz 5063 0
24° 96.1% 1503.3Hz 5063 0
25° 96.1% 1515.9Hz 5219 0
24° 94.1% 1528.5Hz 5219 0
25° 92.9% 1534.8Hz 5281 0
25° 92.9% 1534.8Hz 5281 0
25° 91.8% 1566.2Hz 5281 0
26° 90.2% 1566.2Hz 5500 0
26° 92.2% 1578.8Hz 5406 0
26° 92.5% 1604.0Hz 5531 0
26° 92.5% 1597.7Hz 5531 0
27° 95.7% 1604.0Hz 5625 0
27° 99.6% 1604.0Hz 5656 0
27° 100.0% 1591.4Hz 5688 0
28° 100.0% 1604.0Hz 5781 0
29° 100.0% 1604.0Hz 5750 0
28° 100.0% 1604.0Hz 5813 0
29° 100.0% 1604.0Hz 5844 0
29° 100.0% 1604.0Hz 5875 0
29° 100.0% 1604.0Hz 5938 0
30° 100.0% 1604.0Hz 6000 0
30° 100.0% 1604.0Hz 5938 0
30° 100.0% 1604.0Hz 6031 0
29° 100.0% 1604.0Hz 6063 0
29° 100.0% 1604.0Hz 6125 0
29° 100.0% 1604.0Hz 6250 0
29° 100.0% 1604.0Hz 6156 0
28° 100.0% 1604.0Hz 6219 0
29° 100.0% 1604.0Hz 6313 0
28° 100.0% 1604.0Hz 6313 0
28° 100.0% 1604.0Hz 6344 0
28° 99.6% 1604.0Hz 6438 0
27° 100.0% 1604.0Hz 6438 0
28° 100.0% 1604.0Hz 6438 0
28° 97.6% 1604.0Hz 6469 0
28° 94.9% 1604.0Hz 6531 0
27° 76.5% 1604.0Hz 6531 0
28° 55.3% 1604.0Hz 6625 0
32° 33.7% 1113.3Hz 6594 0
44° 17.3% 226.4Hz 6500 0

I think the base timing is off & I'm going to fix that tonight. The next thing that seems weird is the airflow peak. Compared to other "good" logs I've seen online, the airflow seems to come on late. These logs are done a lot closer to sea level, though. What should I see here at altitlude?

Thanks,

-Mike

[Carl Morris]

Airflow in mass/time (Hz is close enough) is an indicator of the approximate horsepower curve. Airflow in mass/rev is an indicator of the approximate torque curve. This is saying your hp peak is somewhere above 5500rpm, you can't tell more than that because of the 1600Hz logging cap, and also because you let off before the airflow went back below 1600Hz. Looks like you were probably at full boost by 3300rpm or so, mass/rev or "load" would be a better way to know since torque is pretty much proportional to boost.

[mpdeneen]

Airflow in mass/time (Hz is close enough) is an indicator of the approximate horsepower curve. Airflow in mass/rev is an indicator of the approximate torque curve. This is saying your hp peak is somewhere above 5500rpm, you can't tell more than that because of the 1600Hz logging cap, and also because you let off before the airflow went back below 1600Hz. Looks like you were probably at full boost by 3300rpm or so, mass/rev or "load" would be a better way to know since torque is pretty much proportional to boost.

Thanks Carl.

So short of the base timing being off, does this seem like a normal log? I'm a little confused as to what to expect and I want to make sure everything is running the way it should before I do any more modifications.

-M

[XakEp]

I can honestly say I dont know where I see peak airflow - it just keeps climbing.

[mpdeneen]

I can honestly say I dont know where I see peak airflow - it just keeps climbing.

Should I see the max 1604 hz as late in the rpm band as I am or should I hit that sooner?

(Probably the question I should have asked the first time...)

-M

[sbiggi]

That high timing on pump gas is killing your spool.

I take you have upgraded injectors and afc or something? Either that, or at 10psi the evoIII doesnt really flow much.

[mpdeneen]

That high timing on pump gas is killing your spool.

I take you have upgraded injectors and afc or something?

No, I'm trying to get all the bugs out of the way before I change anything else. Stock ECU, 450cc injectors. I believe the base timing is off. I'm going to check that tonight...

-M

[XakEp]

That high timing on pump gas is killing your spool.

I take you have upgraded injectors and afc or something? Either that, or at 10psi the evoIII doesnt really flow much.

Agreed. Thats some REALLY high timing.

[mpdeneen]

The first order of business is to check the base timing and set it to 5*BTDC if it's not there. What else could change the timing like that? What sort of numbers should I expect?

Thanks for all the help,

-Mike

[mpdeneen]

Ok. Found a loose vacuum line. Base timing is at 5* btdc, turned down the base idle just a bit. New log:

Tim. TPS MAS RPM Knock
25? 100.0% 666.7Hz 3125 3
25? 100.0% 717.1Hz 3156 2
24? 100.0% 786.3Hz 3219 2
22? 100.0% 855.4Hz 3281 2
21? 100.0% 918.3Hz 3344 1
21? 100.0% 981.2Hz 3438 1
21? 100.0% 1012.7Hz 3531 1
21? 100.0% 1037.9Hz 3594 0
22? 100.0% 1056.7Hz 3688 0
21? 100.0% 1094.5Hz 3750 0
21? 100.0% 1113.3Hz 3844 0
21? 100.0% 1144.8Hz 3906 0
21? 100.0% 1188.8Hz 4000 0
21? 100.0% 1207.7Hz 4063 0
21? 100.0% 1251.7Hz 4156 0
20? 100.0% 1289.5Hz 4250 0
21? 100.0% 1320.9Hz 4344 0
21? 100.0% 1358.6Hz 4406 1
21? 100.0% 1396.4Hz 4438 1
20? 100.0% 1434.1Hz 4531 0
20? 100.0% 1478.2Hz 4594 0
19? 100.0% 1503.3Hz 4688 0
19? 100.0% 1547.3Hz 4719 0
20? 100.0% 1572.5Hz 4813 0
20? 100.0% 1572.5Hz 4875 0
19? 100.0% 1604.0Hz 4906 0
20? 100.0% 1604.0Hz 5031 0
19? 100.0% 1604.0Hz 5031 0
20? 100.0% 1604.0Hz 5125 1
20? 100.0% 1604.0Hz 5250 1
20? 100.0% 1604.0Hz 5281 0
21? 100.0% 1604.0Hz 5281 0
21? 100.0% 1604.0Hz 5313 0
21? 100.0% 1604.0Hz 5438 0
21? 100.0% 1604.0Hz 5406 0
22? 100.0% 1604.0Hz 5500 0
22? 100.0% 1604.0Hz 5594 0
23? 100.0% 1604.0Hz 5594 1
22? 100.0% 1604.0Hz 5719 0
24? 100.0% 1604.0Hz 5688 0
24? 100.0% 1604.0Hz 5750 0
24? 100.0% 1604.0Hz 5875 0
24? 100.0% 1604.0Hz 5906 0
24? 100.0% 1604.0Hz 5969 0
25? 100.0% 1604.0Hz 6031 0
26? 100.0% 1604.0Hz 6000 0
26? 99.2% 1604.0Hz 6094 0

[Paul]

I see max airflow at peak rpm.

Paul

[sbiggi]

Do you have any piggyback fuel control or is it just the stock ecu?
Also, what is your injector duty cycle?

The reason I ask is that you arent even hitting the top of the timing and fuel maps, and that doesnt take much airflow. I'm betting you could turn up the boost safely because your timing numbers will come down as airflow increases.

If the airsignal is unmolested, you are barely touching 20 - 23 lbs/min of airflow (just looking at timing and off the top of my head)

[mpdeneen]

Do you have any piggyback fuel control or is it just the stock ecu?
Also, what is your injector duty cycle?

The reason I ask is that you arent even hitting the top of the timing and fuel maps, and that doesnt take much airflow. I'm betting you could turn up the boost safely because your timing numbers will come down as airflow increases.

If the airsignal is unmolested, you are barely touching 20 - 23 lbs/min of airflow (just looking at timing and off the top of my head)

Just the stock ecu right now. I want to make sure everything is doing what it should before I ask more from it. My concern is that I'm not dipping into the 15-16* range when boost hit. I checked the base timing, and it was perhaps a little past the 5* mark, but pretty close considering the angle. I haven't checked IDC yet, that comes after I make sure everything is running as it should.

So you think that increasing boost will bring the timing down?

-M

[sbiggi]

Base timing has absolutely nothing to do with what the logger reads. The logger assumes you have it set at 5 degree just like the ecu does, so it reports what it 'thinks' is happening.

The reson your timing doesnt dip is because your airflow numbers are so low that you dont hit the top of the timing map. I dont have my normal tuning program on this computer... but here is a screen shot of the stock timing map for a 1g from evilscribe.

http://www.awdboost.com/seth/images/timing.jpg

[mpdeneen]

Base timing has absolutely nothing to do with what the logger reads. The logger assumes you have it set at 5 degree just like the ecu does, so it reports what it 'thinks' is happening.

The reson your timing doesnt dip is because your airflow numbers are so low that you dont hit the top of the timing map. I dont have my normal tuning program on this computer... but here is a screen shot of the stock timing map for a 1g from evilscribe.


Thanks. I think I've got a better idea of what's going on in there. So timing gets pulled when I hit the top of the timing map based on rpm & airflow and then the timing is slowly added back in until I start knocking?

So the only reason timing gets pulled is if I hit the top of the timing map or I start knocking, otherwise it stays on the map?

-M

[sbiggi]

Timing doesn't get pulled unless you are knocking, or have been knocking.
The maps are what max timing will be.

Timing is subtracted from what the ignition maps says depending on octane count, and instantaneous knock correction.

If you are flowing anything above 2.06 grams/rev the ecu will just use the timing values at 2.06 grams/rev. Unless you have a modified eprom with the extended timing/fuel maps, then the maps support 4.12 grams/rev.

[mpdeneen]

Timing doesn't get pulled unless you are knocking, or have been knocking.
The maps are what max timing will be.

Timing is subtracted from what the ignition maps says depending on octane count, and instantaneous knock correction.

If you are flowing anything above 2.06 grams/rev the ecu will just use the timing values at 2.06 grams/rev. Unless you have a modified eprom with the extended timing/fuel maps, then the maps support 4.12 grams/rev.

Ok. I think I've got it. Right now I'm well within the timing map, just about in the middle, actually. I've got plenty of room to raise boost as long as the fuel system can feed it and I don't overrun the MAS.

Thanks for all the help.

-Mike