New member! Some questions.

[ThexGovenor]

Ok so Im new to the tuning world and have been lurking the forums hard and bought Greg Banish's book. I own a 2006 Cobalt SS with some extensive work done to it. I have always had my tuning done at ZZP and have been happy with it. However I am moving to the Seattle area and figured I needed to be able to log and tune on my own! Anyway I had a E85 tune on it and it made great power (360whp) however it had some annoying idle surge. I had ZZP switch the car back to 93 pump gas and now im getting a decent amount of knock and the idle surge is still present. So now I need to get that fixed. Mods to the car are as follows:
2006 Cobalt SS Supercharged 2.0 Liter I4
Harrop 1320 TVS supercharger (2.7 pulley ~20lbs of boost)
3” ZZP intake
75 Lb valve springs
ARP Head Studs
Ported head
ZZP Stage 2 Camshafts
80# injectors with return style fuel system
ZZP Longtube header and downpipe
ZZP 2.5” catback
GM performance parts upgraded clutch
Griffen Heat exchanger
Dual pass intercooler plate
Option B
How do you shorten a log?
initial tune.hpt nolan.hpl

[ThexGovenor]

at roughly 9:30 you can see the idle surge.

[MMGT1]

Your really running rich there...REALLY RICH. I would start by taking/removing 10% from that MAF table, then get it close in the low range, disable the MAF, tune your VE Table. Get VE in good shape and then re-enable MAF and tune it, full range. Get both tables to within 2% error. I would also bump timing in that Idle table so there isn't such a harsh transition going from Idle to Load... disable trims and go OL to get VE, then tune MAF, then tune timing
I think your combo of being rich and having really low timing is making a mess of your idle
Hit the stickies in this section, you have a lot of great info available for your platform here

[cobaltssoverbooster]

your fuel injector settings will correct the surging issue. the 80's run perfectly smooth once the flow and offsets are dialed in for your specific engine and set of injectors. read the injector threads and use the verification methods to double check your injector settings.

mmgt- you have a good point and idea but unfortunately this issue is fixed 99% of the time by proper re-calibration for the specific injector set. after you read enough of the lsj posts on the forum you will both see this true quickly.

[ThexGovenor]

I'll look into the scalings. Thank you! If that doesn't work I'll try leaning it out

[MMGT1]

Cobalt has your platform down man, he has you on the right track. As you will read over and over, your tune has to have good injector data, no two ways about it. Once you have good data in your tune for them, take the advise I gave you there, apply to your tune, and read until your eyes bleed, then read some more...hahaha

[cobaltssoverbooster]

Offest data test:

set into speed density mode, and make a good ve base correcting the afr to as perfect as you can get it. you will know when your there as your afr error will start to switch back and forth in small adjustments. like 1% or less.

select entire offset data table. multiply by 10% and save as separate file. load it and record data.
the test will pass if the recorded data shows the 10% added fuel being removed by 10%. if you add 10% and it removes 9% or 11% then you have some adjusting to do on your offset values.

the offset data for lsj ecu's is a value half of the actual required value. EX: .250 for a plot data is internally corrected by the ecu to read .500. thus the plotted data must be half of the required amount. if you figured out you need .500 and you entered .500 into the plot field the ecu will internally correct the value to 1.00. keep this in mind when making adjustments. they may be small but in reality they are double the visually adjusted amount.

[ThexGovenor]

Ive been looking over a lot of the stuff on 80# injectors. and It seems that ZZP does their scalings drastically different than Omegas spreadsheet. They dont even use a flow rate modifier? Im tempted to just switch over all the injector scalings to omega's and see if that helps. Sound like a good idea?

[GM COBALT SC SS]

zzp does injector scaling. our ecu is limited to roughly 120# injectors. when you scale the airflow and flow rate and airflow by half, it allows you to double that limitation. also. this is why we can run ID 2000s. i dont know anyone who does, but you can. it would be a good idea to find out the fraction at which it was scaled, but id bet its .5

its really up to you whether you want to use zzps or omegas data. but i dont think the scaling will affect offset data test. it will affect the way timing is commanded. so you dont want to just copy and paste omegas data onto the zzp tune your currently running.

here is a good article for injector scaling:
http://wpdev.injectordynamics.com/wp...SteckScale.pdf

[ThexGovenor]

I appreciate it. Just curious as to why its running so rich. What Tim said he did was just change the fueling from the e85 tune. Ill try to do that offset test today and report back.

[cobaltssoverbooster]

Offset data changes with injectors.
Disabling flow modifiers means your using a smaller injector than the max limit. By scaling they have to change the injector flow by their scale value which most likely puts them under the 63.5 lb hr limit on the flow table.

[ThexGovenor]

Well bad news, went to do the test and my wideband crapped out on me

[jp1600]

It almost looks like its still set up for e85 if you just look at the fueling, good god its unbelievably rich

[jp1600]

Oh, and during the surge your ecu commanded a 10.1 a\f ratio and shut of your fuel trims

[cobaltssoverbooster]

e85 stoich is like 9.76 so if hes was running e85 still it would be ok.

[jp1600]

just going on a basic number of 30%, he would be running fine for e85 yes. I'm wondering what he did to adjust fueling because I would not drive with the tune like it is.

[574]

I knew you had to be rich to stay safe because thats just zzp's style. But wtf

[ThexGovenor]

Well folks good news. I have taken your advice, read everything I could and I believe fixed my tune. Here you go! Also I have switched back to E85 thank goodness. There is a second gear pull to almost 7500 at 32 minutes in the log. I leaned out the PE so Im running a 11.4 AFR (gas scale) to battle the IDC. If you see anything wrong let me know! I am planning on further refining the top end MAF on a dyno later this week. rate.Nolan Smooth VE.hptLog 2 MAF STFT.hpl
Edit. When I did the log the car was in Open loop except Short term fuel trims were enabled. I have since changed it all back to allow the car to go to closed loop.