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DSM Link V2.5 Starting to tune NEED HELP

Galantvr4559

Well-known member
Joined
Jul 15, 2011
Messages
264
Location
Denver, CO
So I just recently purchased link v2.5 from a guy here on the org and i just want to know how to do initial set up for start up, idle, and some helpful tuning pointers. I have an AEM wideband soon to be installed and then link. Is there maybe some stater maps to get me going or is it as simple as setting for global and deadtime and start her up and fine tune everything. I have watched some videos on youtube on simple set up but i guess i am asking to see if there is a starting point. My set as fallows gm maf, maft, precision dual bb 50 trim, ic short route 2.5 piping and 28x10x2.75 core size, fic 750cc injectors, ss internal wg o2 housing atmosphere dump to 3in exhaust with no cat, emissions deleted, act 4 puck unsprung clutch, jacks stg 2 with a 4 spider center diff, rebuilt driveshaft and a 4 bolt rear end.

Any help is very much appreciated. Maybe a site i can go to, to download some maps.

Thanks
Bryan
 

BluFalcon

Well-known member
Joined
Jan 20, 2002
Messages
1,312
Location
Wichita, KS
This is what I used. Pulled it off of Tuners or Talk a long time ago.

Basic DSMLink Tuning Guide
(This guide is exactly what the title implies, a basic guide to tuning. It is not intended to teach you, or tell you, everything needed to tune a DSM. Research will be required to fully understand the terms, values, and procedures below. With that said, the people involved with any and all aspects of this guide are NOT responsible for ANY damage done to your car.)

Written and edited by: Shane2GSX and NickNorth11


Before You Start:
• Verify that Base Timing is correct
• Verify that Base Fuel Pressure is correct (1g manual = 37 psi; 1g auto = 43.5;
• 2g = 43.5 psi)
• Verify that there are no boost leaks
• Ensure all other components are working correctly
• Swap plug wires to account for different CAS (97-99)
• Approximation of desired values: (Some of these must be obtained manually and some via DSMLink. Others are simply values to monitor and keep within given parameters.)

A/F Ratio (closed loop) 14.7
(open loop) 11
AirFlow (compare to specific turbo output)

AirFlowPerRev (at idle)
(1g) M/T = .27 +/- 10% (.24 - .30)
A/T (neutral) = same as M/T
(drive) = .31 +/- 10% (.28 - .34)
(2g) .31 +/- 10% (.28 - .34)

CoolTmp (1g) x>189°, sufficient operating temp. to tune
(2g) x>179°, sufficient operating temp. to tune
if: x<206°, full timing
206°<x<224°, -1°
x>224°, -2°

IdleSw (car off / ecu on) 1

IntTemp 34°<x<84

ISCPosition 30 (at idle)

LearnedIdleAdj 140 (at idle)

LTFT Lo x→0, (0+/- 5)

LTFT Mid x→o, (0+/- 5)

Front02 cycles around .5 (.05-.95)

RawThrotPos 32

ThrotPos if: idle, 0
WOT, 100

TPSvolts .63 (when RawThrotPos = 32)


Setting Initial Parameters:
1. Setup wideband operation within dsmlink.
2. If needed, change BoostEst to your respective engine size. (2.0L, 2.3L)
3. Set the A/F Ratio prefs for your injectors.
4. If base timing is off, adjust timing sliders across the board to compensate. (if 3, add 2)
5. If needed, cancel out any CEL’s due to already known causes. (such as rear O2)
6. For safety and if desired, set Knock CEL to 3 degrees knock.
7. Set global and dead time parameters according to specifications for injectors.
8. Set desired values to be logged.





Closed Loop Tuning (Cruise/Idle):
1. Setup DSMLink to Log the following (if available):
a. TPS
b. STFT
c. LTFT Lo
d. LTFT Mid (2G) or LTFT Hi (1G)
e. MAFRaw
f. Wideband
g. Boost sensor (GM 3 bar, AEM, etc.)
2. Turn on vehicle and let warm properly.
3. Drive normally, cruising for at least 10 minutes - Do not go WOT
4. Let car idle for 5 minute before shutting it off - Stop logging
5. Choose your method of closed loop tuning by first determining if AirflowPerRev is at an acceptable value at idle. If AirflowPerRev is not acceptable, evaluate whether adjusting fuel trims with airflow sliders will improve the idle AirFlowPerRev value. If airflow adjustments will improve AirFlowPerRev, begin tuning using step 4 of Method 1. If AirflowPerRev is acceptable, proceed to step 4 of Method 2.


Method 1 – Airflow Metering:
1. Turn on vehicle and let warm properly.
2. Begin logging. Drive normally, cruising for at least 10 minutes - Do not go WOT
3. Let car idle for 5 minute before shutting it off - Stop logging
4. Compare LTFT for idle (Lo) and cruise (Mid) operations – Strive to get as close to 0% as possible. (1Gs are limited to a minimum of -4.7% fuel trim and should therefore strive to attain a slightly positive fuel trim; 0 - +5%)
5. If either is greater than 5% from 0%, proceed to step 6. If not, and your happy with your %, you may stop.
6. If LTFT Lo is negative, decrease the 50 Hz slider in the amount of that value. (i.e. If LTFT Lo is -10%, decrease the 50 Hz slider from 0% to -10%).
7. If LTFT Mid is positive, increase the 150 Hz slider in the amount of that value. (i.e. If LTFT Mid is 10%, increase the 150 Hz slider from 0% to 10%).
Or: (From method 2) If LTFT Lo is greater than LTFT Mid, increase dead time. If LTFT Lo is less then LTFT Mid, decrease dead time.
8. If adjustments are made, return to step 1.


Method 2 – Fuel Delivery:
1. Turn on vehicle and let warm properly.
2. Begin logging. Drive normally, cruising for at least 10 minutes - Do not go WOT
3. Let car idle for 5 minute before shutting it off - Stop logging
4. Compare LTFT for idle (Lo) and cruise (Mid) operations – Strive to get as close to 0% as possible. (1Gs are limited to a minimum of -4.7% fuel trim and should therefore strive to attain a slightly positive fuel trim; 0 - +5%)
5. If either is greater than 5% from 0%, proceed to step 6. If not, and your happy with your %, you may stop.
6. If LTFT Lo is greater than LTFT Mid, increase dead time. If LTFT Lo is less then LTFT Mid, decrease dead time. (If dead time is adjusted, adjust the A/F props settings for the new value).
7. If LTFT Lo and LTFT Mid are equal but non-zero, adjust global setting.
8. If adjustments are made, return to step 1.


Open Loop Tuning (WOT) Fuel & Timing:
1. Choose a desired fuel/octane level.
2. Choose a desired boost level that you want to run. Dial your boost in at a lower boost setting to begin with, depending on turbo size, probably no more than 1 bar.
(An alternate to the previous method is to start at your target boost level with conservative settings, i.e. low timing and rich mixture. Make a few pulls before tuning to ensure safe operation before continuing with this method).
3. Choose a proper A/F Ratio to shoot for in the entire RPM range – Some common A/F ratios are 10:1, 10.5:1, 11:1, 11.3:1, 11.5:1. The proper A/F ratio will depend on your specific vehicle and its setup. While there are too many variables to list when determining a proper A/FR, some of the common ones are fuel octane, intercooler efficiency, and turbo size. In most cases, on a properly running DSM, on pump gas with an efficient intercooler, an 11:1 A/FR is a common and safe ratio to make good power with.
4. Ensure that all values you want to log are set. (The following are recommended).
a. Wideband
b. Boost sensor
c. EGT
5. After warming the car properly (warm car, drive at cruise for 10 min., idle for 5 min.), data log a 3rd gear pull from 2000 RPM to redline. Keep a very close eye on Knock, A/FR, and EGT’s for anything that might spell trouble.
• If you see ANY Knock, increase fuel sliders. If A/FR is already richer than your target, reduce timing by a degree instead of increasing fuel.
• If no Knock is present and your A/FR is leaner than your target, increase fuel to desired level. If A/FR is richer than your target, and you’re at your target boost PSI, decrease fuel.
6. Allow car to cool down between runs. (Number of runs between cool down periods will be dependant on intercooler efficiency and boost level, among other things. Not doing this will result in inconsistent results).
7. Continue logging runs in this manner until you reach your target A/FR with no Knock.
8. Once you reach your target A/FR with no knock, raise boost by 5 PSI or less. Repeat steps 5 through 7 until you reach your target boost PSI.
9. Once you’ve reached your target boost PSI and desired A/FR with no knock, increase timing by one degree and log another 3rd gear pull from 2000 RPM to redline. Again, keep a close eye on Knock, A/FR, and EGT’s.
10. Repeat step 8 until you see one degree of knock retard. At that point, reduce timing by one degree. (Aim for high teens to low 20s for timing advance. Higher is better.)
11. Finally, do a full run from 1st through 4th gear, watching Knock, A/FR, EGT’s, and boost. Watch knock especially closely. Ensure you run the car very hard. If you see any Knock, you may need to reduce timing. If you see that your A/FR’s are off, you may need to adjust your fuel.
 

Galantvr4559

Well-known member
Joined
Jul 15, 2011
Messages
264
Location
Denver, CO
I am installing next weekend and after i install and log some data i will for sure post it so i can get some feedback. Thank you very much for the information very helpful and a good explanation of what to do for initial start up and tuning. Logs to come soon
 

Galantvr4559

Well-known member
Joined
Jul 15, 2011
Messages
264
Location
Denver, CO
Im not sure how to post a log onto this site. does anyone have any suggestions. When trying to get some tuning done i noticed that ltft lo and ltft hi arent doing anything at all when driving around. I dont want to do any pulls until i get some settings straightened out. I am really new to this. If there is someone in colorado that knows how to use and tune with dsm link v2.5 or v3 i would love some help. pm me. I appreciate all the help guys.
 

ktmrider

Well-known member
Joined
Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
You should be reading the DSMLink FAQ front-back-front then again before diving in like this. Also join the Forum on Link and troll, troll, troll.

LTFT = Long Term Fuel Trim, key being Long Term ( ie won't change very quickly ). However the STFT should/will be changing quickly ( Short Term ). LT tells you how your base fuel trims are set, ST tells you how much fuel is being added/subtracted from said base trims. LT will slowly adjust over time, target should be +/-3.
 
Last edited:

slugsgomoo

Well-known member
Joined
Oct 16, 2003
Messages
3,770
Location
Tacoma, WA
have you gotten onto the dsmlink forums yet? click

There's an incredible amount of knowledge there, and they're happy to help.
 

Galantvr4559

Well-known member
Joined
Jul 15, 2011
Messages
264
Location
Denver, CO
Ya i finally got a user name and password. Had to email ecm link to get It. Thanks for all the help guys i very much appreciate it.
 
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