LSA E67 Load question

[lockner13]

I didn't seem to find what I was looking for in the search, I may not have worded it correctly though so please forgive me. I have a 2015 V2 cts-v coupe automatic and I have installed a airaid intake, TSP headers, colder plugs, and x pipe on it. other than that its stock. I have started to learn the tuning process on this ecm (typically tune import applications), basically started with rescaling the maf curve only with a wideband and using maf eq error chart to gain the info. I've noticed that under WOT on the logs it shows my load will be higher than what's on the tables in spark table rows. My question is, do I need to rescale the tables with a load based axis? Also, what all tables would need rescaled then and what is the max load to scale things to or what is recommended? Im new to GM tuning, but feel with a little help or guidance here and there, I can get it all figured out as I'm not new to tuning, just more along the lines of COBB and opensource or AEM standalones and not the likes of HPT or EFIlive tuning on American made stuff. I've attached a recent log and the hpt file. Sorry for the newbie questions on this, but I figured this would be the place for the best answers!

Thanks everyone!
Ben

[blindsquirrel]

Why do you think it would need a different spark timing at 1.50g or 1.40g than it has at 1.36g? WOT is easy and simple, it's light throttle/load where you need fine control and good resolution.

[SiriusC1024]

First sentence of the second page should clue you in to how this is relevant:
http://injectordynamics.com/wp-conte...SteckScale.pdf

Pick a scaling factor that gets what you need.

[lockner13]

Why do you think it would need a different spark timing at 1.50g or 1.40g than it has at 1.36g? WOT is easy and simple, it's light throttle/load where you need fine control and good resolution.

I suppose it was the way I was taught, that said, I'm new to GM ECU tuning all together and trying to get the best understanding I can. For example in COBB AP maps or opensource on a Subaru, the maps are setup with a load axis of say 2.55g/rev then you are "running blind" topped out in the last cell of the map to make any changes. If you rescale all the load based maps, you then have more fine control over what it does in any other load ranges above that 2.55g/rev. They base ignition, knock, and fuel mostly off this axis, so basically you rescale the maps with this axis type and you have more control in what it will do when requested. The thing is, I didn't think this would really be required on the GM ECU unless I changed injectors or made some kind of bigger changes to engine setup. I only changed the intake, headers, and x-pipe on my car, no injectors or anything else, so I just didn't think it would be maxing the airmass out on the fuel and spark tables requiring a rescale until I made bigger changes. I am trying to learn and hope that my reference to a totally different platform doesn't seem stupid, it's just what I know. I want to learn the GM ECU stuff and be able to tune my own car so I have the best understanding of what's going on with my setup if anything comes up that needs attention.

Thanks!!
Ben

[lockner13]

First sentence of the second page should clue you in to how this is relevant:
http://injectordynamics.com/wp-conte...SteckScale.pdf

Pick a scaling factor that gets what you need.

Thank you! This is a great asset to look over! my main question I guess is, why is it necessary to rescale with just the small part changes i've made? Since I haven't changed injectors, pulley, fuel system etc. I guess I didn't think it would change the airmass the ecu is seeing so much. Sorry if my questions are stupid lol I'm just trying to get the best understanding of things that I can.

Thanks!!
Ben

[SiriusC1024]

The ECU gets the airmass from what you tell it. If the airflow models are wrong then the reported airmass will be wrong. That or injectors. Stock injectors?

Looking at your tune all that appears ok. Maybe GM knew 1.36 max airmass would be sufficient.

Another thing I noticed is that the Cylinder Airmass axis can be edited. Just click on the label. No need to scale anything, so that makes things a lot easier.

[lockner13]

ok, so could it be that the maf scale where Im making changes to it are just changing the reported airmass that much? Yes, stock injectors for now. The car was completely stock, I added an air-aid and green filter, TSP 2" headers, and TSP X-pipe to oem mufflers. thats all thats done to it. I may have the maf scale a bit too high causing it to report too much airmass entering the engine. Im still working on learning the maf error chart and making changes based off of that and the wideband.

[blindsquirrel]

Maxing out the g/sec scale on the spark map is not the same as hitting the ECM's airflow limit, which you aren't going to do with your combo. That's like 1000+ HP stuff. The timing will be fine carrying the 1.36g timing all the way out.

[lockner13]

Maxing out the g/sec scale on the spark map is not the same as hitting the ECM's airflow limit, which you aren't going to do with your combo. That's like 1000+ HP stuff. The timing will be fine carrying the 1.36g timing all the way out.

I wasnt thinking I was hitting the ecu airflow limits, but I was concerned about reaching the top end of the axis shown in the tables. I just didn't know if I should make changes to the airmass rows or literally rescale the whole maps or not. I appreciate the help understanding this. If, down the road I add more parts requiring a retune, is it advisable to change the airmass value labels higher so I have more head room in the tables or would I need to do a full table rescale at that point?

Thanks
Ben

[blindsquirrel]

Say you end up where it's eventually doing 1.60g, and that calls for 18* or 17* instead of 20*. You would not ever know the difference in 17/18* and 20*, when it's zipping through the (actual) 1.36g row (and going through there very quickly, usually) on its way to 1.60g. If it was being used for WOT only you could honestly put one single value in the whole table and it would do WOT stuff very nearly identical to what it would do with a finely-tuned full spark table. People just get way too hung up on this spark-airmass thing when there's really no there there. Nothing real to be gained by extending it, and nothing real lost by not.

[blindsquirrel]

Now, if you could add whole new rows to the table, which wouldn't sacrifice resolution down low where it's really useful to be able to fine tune for part throttle/low load, then I'd be all for it. But rescaling the spark axis just gives you less control where it's needed, in exchange for more control where you'll probably end up just putting in the same numbers it would be at without scaling anything.

[lockner13]

Now, if you could add whole new rows to the table, which wouldn't sacrifice resolution down low where it's really useful to be able to fine tune for part throttle/low load, then I'd be all for it. But rescaling the spark axis just gives you less control where it's needed, in exchange for more control where you'll probably end up just putting in the same numbers it would be at without scaling anything.

ok, that makes sense to me for sure. I agree that you def need more fine control in the part throttle/low load ranges. Good info!

Thanks again!
Ben

[sgod1100]

I didn't seem to find what I was looking for in the search, I may not have worded it correctly though so please forgive me. I have a 2015 V2 cts-v coupe automatic and I have installed a airaid intake, TSP headers, colder plugs, and x pipe on it. other than that its stock. I have started to learn the tuning process on this ecm (typically tune import applications), basically started with rescaling the maf curve only with a wideband and using maf eq error chart to gain the info. I've noticed that under WOT on the logs it shows my load will be higher than what's on the tables in spark table rows. My question is, do I need to rescale the tables with a load based axis? Also, what all tables would need rescaled then and what is the max load to scale things to or what is recommended? Im new to GM tuning, but feel with a little help or guidance here and there, I can get it all figured out as I'm not new to tuning, just more along the lines of COBB and opensource or AEM standalones and not the likes of HPT or EFIlive tuning on American made stuff. I've attached a recent log and the hpt file. Sorry for the newbie questions on this, but I figured this would be the place for the best answers!

Thanks everyone!
Ben

I just rescaled my spark airmass table as you can edit the rows. You will lose a little resolution, but I like to be able to edit my spark if need be and not just run off of the 1.36g row. I've seen 1.75-1.8g before so I'm way above the stock table

[Alvin]

I rescale my spark airmass tables. I typically only rescale 1 g and above. No need to reduce resolution down low.

[sgod1100]

I rescale my spark airmass tables. I typically only rescale 1 g and above. No need to reduce resolution down low.

yyyup, I think I was right around that area as well when I made the graduations larger

[lockner13]

Thank you guys so much for all the help on this! This is the info I needed to know. One last question I have is do you all rec turning off ltft permanently or just for tuning the cruise range, then re-enable ltft when done? Also, do you rec tuning the maf only for the mods I have done above or tune maf then vve table?

Thanks!
Ben

[sgod1100]

Thank you guys so much for all the help on this! This is the info I needed to know. One last question I have is do you all rec turning off ltft permanently or just for tuning the cruise range, then re-enable ltft when done? Also, do you rec tuning the maf only for the mods I have done above or tune maf then vve table?

Thanks!
Ben

I've had my LTFTs turned off permanently for a few years now. Just using the STFTs for fueling corrections and no issues

[lockner13]

I've had my LTFTs turned off permanently for a few years now. Just using the STFTs for fueling corrections and no issues

Ok, awesome. What would you rec. on the fuel tuning? Make maf only changes or maf changes, then disable maf and make vve changes, or is there a more preferred way to do it?

Thanks!
Ben

[SiriusC1024]

https://forum.hptuners.com/showthrea...-the-Same-Time

[sgod1100]

Ok, awesome. What would you rec. on the fuel tuning? Make maf only changes or maf changes, then disable maf and make vve changes, or is there a more preferred way to do it?

Thanks!
Ben

multiple ways to do it...when I started tuning a few years ago I always disabled one to tune the other but now there are ways to just tune both at the same time. Linke that SiriusC1024 posted will get you going with that process