Switching to speed density advice

[gsexxx]

Hey guys, I have read through the wiki on the link website and have read numerous threads on the topic. However, I have a question about dialing in the ve tables using the mas. I have the speed density plug n play harness and already have my iat in my upper intercooler pipe and a 4 bar map sensor that is ready to go in. I am fairly new to dsmlink, especially sd, and don't fully understand this process: sdveadjsdratio [ECMTuning - wiki]

My question is are you supposed to log the gm map sensor and iat when dialing in the ve tables with the mas? The plug n play harness plugs into it so I cant log the map & iat while running the 2g maf. Sorry if it is a stupid question, I tried to find the answer through searching but I didn't find what I was looking for. I would really appreciate it if someone could help me out so I can proceed to switch over to sd. Thanks a lot!

 

[ColtiXim]

Maybe this thread could help you : http://www.dsmtuners.com/forums/articles-tuning-ecu/395564-how-tune-1g-v3-sd-ecmlink-no-maf.html

 

[synthetek]

You would have to use other inputs at first. Connect the MAP to the MDP input and the IAT to another available input and then switch them to the MAF plug after you do the calibration if you want to use the speed density cable.

 

[Dude McGee]

The SD Ve adjust combined ft tool works very well. Just plug in the map and iat, ditch the maf, and use the generic sd table. It should get it to fire up, although afr will be off. the article above covers everything after that.

 

[gsexxx]

Thanks for the quick responses guys, I think I am going to use the SD Ve adjust combined ft tool to get it dialed in like Dude McGee mentioned. Thanks for the link as well!

 

[deylag]

For my Speed Density setup I was going to connect the IAT sensor to the MAF connector.

They are available through this website: http://www.spoolinup.com

 

[clipto]

I think iat sensors are over rated. Never used one in all the years i ran sd just plug in that map sensor and get a tune. If you dont know how to tune sd there so many great tuners that can do it. Try my1gdsm for a great remote tune at a good price!

 

[turbojo]

I think iat sensors are over rated. Never used one in all the years i ran sd just plug in that map sensor and get a tune. If you dont know how to tune sd there so many great tuners that can do it. Try my1gdsm for a great remote tune at a good price!

Running with out a iat is a bad idea if you don't have a really good intercooler in my opinion the more sensors that you can use to keep your setup safe the better

 

[clipto]

Is true but you can only do so much I mean intake air temps will very per how hot it is a day. Unless you ganna make changes everyday for weather changes to your tune depending how hot it is but idk. All I know is I have been running 3 years without one and have not had one issue without it. All it is to me is a extra clutter and crap in the engine bay well just another sensor but w/e. But find me amazing proof that you absolutely need one and it makes such a huge difference and I will get it. Otherwise I am good just plug in the map sensor and tune your heart out.

 

[gsexxx]

I have been tuning on a maf for almost two years now and have everything I need to switch to speed density so I am going to give it a shot. Reading the wiki and other threads have given me a basic understanding of sd and how to tune with it. I am really interested in tuning and would like to learn and do it myself if possible. Thanks for all the feedback guys I really appreciate it!

 

[GSLENK]

Just do it. You can easily get yourself started using some basic guides. My car runs decently well, and calibration is not difficult if you have the time (once calibration is done, tuning is "easy")

If your injector settings are absolutely correct then its pretty easy to calibrate the VE table. Use the VEadjust tool for SD to get closed loop taken care of (maximize closed loop conditions so you can "overlap" open loop a little.

Next read up on Calan's LinkTools Excel program. It is amazing. You can now easily and systematically calibrate open loop.

So closed lop and open loop are calibrated you should be done calibrating. Then it is back to tuning as regular.

 

[Jon91TSi]

Is true but you can only do so much I mean intake air temps will very per how hot it is a day. Unless you ganna make changes everyday for weather changes to your tune depending how hot it is but idk. All I know is I have been running 3 years without one and have not had one issue without it. All it is to me is a extra clutter and crap in the engine bay well just another sensor but w/e. But find me amazing proof that you absolutely need one and it makes such a huge difference and I will get it. Otherwise I am good just plug in the map sensor and tune your heart out.

If you have your car tuned in 50*f temps, and now the temps are in the 90's, don't you think your tune will be off? The IAT sensor allows the ECU to compensate for the changes, just as an OEM MAS or GM MAF will. Speaking of clutter.. It's only two wires

 

[WES_393]

But find me amazing proof that you absolutely need one and it makes such a huge difference and I will get it. Otherwise I am good just plug in the map sensor and tune your heart out.

We've been over this before. You don't need an IAT sensor, and can use an alternative input such as coolant temperature, but your tune's consistency will suffer. A quote from this page:

However, at wide open throttle, the air temperature seen by the IAT sensor quickly takes over as the primary factor in determining air density. We have logs showing this effect as well with measured A/F ratio dipping to 8.3:1 with IAT at 133F compared to A/F ratio of 9.1:1 at 65F with boost around 20psi. These logs can be found below.

As before, these logs were taken minutes apart from each other on the same car. The only difference between them is air temperature. In the first, air temperature averaged 65F while in the second, it was 133F.

However, unlike the idle logs, measured A/F ratio in these actually *did* change, suggesting that air temperature in these log actually did have an impact on airflow entering the engine.

I'd say .8 difference in AFR at WOT is a huge difference...

I have been tuning on a maf for almost two years now and have everything I need to switch to speed density so I am going to give it a shot. Reading the wiki and other threads have given me a basic understanding of sd and how to tune with it. I am really interested in tuning and would like to learn and do it myself if possible. Thanks for all the feedback guys I really appreciate it!

If you have a MAF and understand the general concepts of tuning, then dialing in the VE table will be cake.

 

[gsexxx]

Going to give it a shot tonight. Thanks for the help!

 

[Troybuilt]

Great Thread!!! Perfect timing!!! New on this site but I've been playing around with Dsm's for 8yrs....finally have one ive stuck with making good power and i am also switching from gm mass to speed density. This helps alot, much appreciated