Just wondering if anyone would be kind enough to give me some feedback on my tune. All my mods including cam specs are in my sig. Feel free to point out anything that stands out to you, good or bad. Any red flags, anything that can be improved ect.

One particular issue the car has is that it will rarely start with the AC on. It'll fire up and die in a couple seconds. I don't know if this is normal or not for cammed cars. Sometimes it'll manage to stay alive, but the RPM falls very very low down to 300-400ish and it kinda struggles there for a bit or it will surge really bad, but eventually jump starts itself back to life at normal idle RPM. Sometimes it even does it with the AC off, particularly the surging RPM. I know it's hard to give good feedback on this without seeing the car do it for yourself but if anything sticks out to you in the tune that might cause what I described please point it out.

Thank you.

 

are you still running a stock intake setup? its hard to tell without seeing a scan log. the startup problem could probably be solved with a little more startup airflow and possible slowing the devay again trial and error there. the a/c torque tables are still stock and usually those get bumped a bit if its having trouble with rpm drops when cruising with ac on.

 

Intake is stock LS6 intake. Thanks for the tips. I will try a bit of trial and error with the things you mentioned, as well as bumping up a/c torque a tad. Will update later with results.

Forgive my newbiness but is a scan log just a scan with vcm scanner or something else? If that'll help out then tell me how to do it and I'll post it up for you and anyone else who finds it useful.

 

Well I bumped up delay and airflow some, and cranked it up cold with the AC on and no dying, low rpm, or surging. However the idle is now a bit high at 900-950ish RPM, so I bumped things back down a tad and started it up. Back to the same issues as before... Must be a really fine line between too little, too much, and just right. Going to keep tinkering till I get it right.

However I don't get why something this simple was so difficult for the guy who "professionally" tuned my car. I took it back to him a couple times and he did some things but nothing changed it and he seemed lost... First time using HP Tuners and I almost got it figured out... Definitely know now not to go back to that guy. Curious how much power may be left on the table to be opened up with a better tuner...

 

I guess no one else has any input?

 

what table did you bump up? if you just bumped up startup airflow it shouldnt idle high after it has decayed post up the tune and i'll look at it again and tell you what i see. the delay is very sensitive i have mine set at 25 for startup and left the other stock then i have the decay set to .15 instead of .8

 

he also left the adaptive idle airflow values fro a/c stock these are usually bumped up to compensate for the ac kicking on

 

I bumped the base running idle airflow table. Was that the correct one to bump? If not, and they don't look right in the new tune file let me know so I can change them back to how they were. I toned it back down a tad and no more high idle. A/C off surging seems to have been completely eliminated with the new changes though. And it hasn't shut off on me with the A/C on, but still some surging and rpm drops. Start up decay is at .8 so I guess he left that stock also?

I'm not sure if I'm looking at the correct one but my start up airflow delay table is at 4 across the whole temp range. Should I change it to 25?

There are a several different numbers under adaptive idle airflow, I'm not sure which ones to bump, and how much to bump them to achieve the desired results?

Am I risking any issues here making these minor bumps in numbers? A/F ratio getting lean or anything of that sort? Don't want to do anything to drastic and damage something.

 

I'll send you some screen shots of what I'm talking about later tonight. The idle running airflow table could still be off but you would have to do a cold idle scan to see. I was talking about startup airflow which is added to that value. You raised the airflow too high so it caused the high idle. Raising the startup airflow will only effect startup which is what I was talking about

 

Alright cool thanks man. I must say drivability has improved a lot with those adjustments I made to the running air flow. Taking off from a stop is just much smoother. I'll tinker with startup airflow a bit next.

 

Good stuff man there's actually a config that tells you how to set running airflow. Search Russ k idle config and it will show you. That will get your airflow right where it needs to be.

 

Was the smoothness increased with ac on or off

 

http://www.hptuners.com/forum/showth...ve-idle-config

 

Smoothness was increased with both A/C on and off. The only issue with the A/C is on initial startup. Once the car runs for a few mins and gets rolling it's fine. I noticed that when taking off from stops, going from idle to moving, that the take off was smoother and there was less RPM drop as I let out on the clutch.

I also bumped up startup air flow just a tad a little while ago and noticed startup improvement with both A/C on and off, but still have RPM falls and surging with the A/C on.

Thanks a lot for the link to that guide. Will start looking over that next.

 

yep use that idle config and that will get your base airflow in check. change the values in the below screen shot to 25 for delay and then add 1.25 g/sec for the startup airflow and then fine tune from there if its not enough/too much etc.



the next is adaptive airflow. these values add or subtract air from the base airflow value depending on what the car needs. in your tune the a/c max and min are both set to .5 g/sec which is stock. this means that when the ac kicks on the compressor might want 2 g/sec more air than with it off but your table only has room for .5. the base airflow vlue in your car may be high enough that thats ok but without a scan you cant tell. pop in these values, they will provide more of a cushion either way for a/c.

 

I appreciate you taking the time to post this stuff man. Forgive my newbiness again, but what does g/sec mean? I don't see that unit in any of the tables. If a given startup airflow box is at 1.50, would adding 1.25 g/sec make the value 2.25 or is it calculated another way?

Also should my startup airflow numbers be similar to what's in that picture? Or is that a stock table or something? Because mine were already much higher than that before I messed with them.

I also started messing with vcm scanner a bit earlier so hopefully I can get some scans up soon. The weekend is coming to a close though so I won't have as much tuning time during the week will definitely keep updating with every change I make though.

 

g/sec is just grams per second. yours may or may not already be in that unit. if you look in the pic above you'll see next to the "+-x" there is a text box and next to that is g/sec if yours does not say that then go to one of the cells in the bottom right click it, go to units and change it. g/sec is the standard tuners use so any specs you get will be in that.

and both those tables were taken directly from your tune. the lower one was called "startup airflow initial" and "startup airflow delay" you may have been looking at frictional airflow. they both add air in the same way just for different reasons. I chose to add to that because the frictional airflow value was already decently high. again that table is what your car is right now at least in the tune you sent first. add to that and see what happens. if the car starts, flares up then drops and dies try increasing the delay longer and slow the decay rate, that will make sure that it waits longer before it subtracts the startup airflow and that it takes out less every millisecond.

and yes if you high light all the cells and enter 1.25 in that top right box then click the + sign it will add 1.25 to all the cells. if you want to reduce the cells by 10% then you would simply highlight them again and enter .9 in the cell box and click the x. increase by 10% would be 1.10 x

 

Ah ok, I got the units right now. I'm going to try and get those changes done during lunch today or tonight after work.

 

Made those changes, start up is even better now but STILL not much success with A/C on starts. Hasn't died on me like it used to but still surges really bad. I guess I should just accept that I can only start the car with the A/C off. However I'm still really happy with the drivability and startup improvements I've made so far.

I tried doing a cold idle scan and setting up the running air flow the way it says to in that guide. I added the Idle Desired Airflow PID to the table, however when I go to histograms there isn't an IDA histogram for me to copy over the running idle airflow table in VCM editor... I don't know how to make that histogram show up. I must be missing something?

 

it should start with ac on it just may take some more fiddling. try adding more to startup and see what happens. another thing you can try is this... 0 out this table. the screen shot is of yours now. you want to change it all to 0. you can find it under tq management-engine-a/c-max retard. this table retards timing when the ac kicks on...its pretty stupid and can cause some of those conditions.




the config is pretty easy, just download it and then open the config in the scanner everything you need should be there in the histogram. do the sca and then under teh desired airflow histogram just right click load all data and ensure its in g/sec