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2009 CTS-V tuning

General Tuning Discussion

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I am just getting started on tuning my CTS-V. I have a zeitronix ZT-3 wideband installed and I am trying to figure out where the best place to start. Currently it is completely stock. I would like to start by seeing if I can tweak the current tune and learn about tuning before I start doing any mods. I do not have access to a dyno, but I do have a lot of country back roads for road tuning.

From my research I see that some people believe the best place to start is with MAF tuning and others say start with speed density. I am not sure what is best, but I have been playing around with MAF tuning to start. I have setup my VCM scanner to do MAF error by adding a new graph setting up MAF frequency sensor and copying in my column headings from my tune (MAF calibration Airflow vs. Frequency). Then doing some logs and taking the error from the table and multiplying the results by % half in my tune. I am not sure exactly how I should drive to pull these logs. I have basically tried to slowly progress through the frequency range and try to spend enough time in each cell to sort of even things out. From what I gather I should shoot to have my log run from -2 to +2 across the board before I move on to speed density. Prior to doing any logs these are the changes I made to the tune to try and make sure I am not in closed loop.

Engine, Fuel, Cutoff

Disable DFCO

Engine, Fuel, Temp Control

Turn of COT

Engine, Fuel, Oxy Sensors

O2 Readiness ECT Maxed to 400*

Engine, Airflow, dynamic

Disable Dynamic Air

Spark, Advance,

Subtract -5%

Any advice would be wonderful. Am I on the right track or should I start over and go a different path? I really would like to get this down, but honestly I do not have enough experience to know if I am doing things correctly or if I am about to mess something up. Thoughts?



Where are you located? Everyone in the US has access to a dyno -- the question is how far away is it? Try googling "chassis dyno near " or "dyno tune near ".

I think the first step is to decide which tools you are going to use to tune and log data from your vehicle. Get those setup and working, learn how to select channels to be logged, and how to look at the data in the logs before you change anything.

From there, I'm sure you'll see something you want to change -- often modifying the drive-by-wire throttle mapping will totally change the character of the car, or you'll find some issue (runs extra rich at wide-open-throttle, long-term fuel trims are large at a certain load, etc) you want to address.

Hey David,

Thanks for the reply. I do have a dyno, but it is 2 hours away. I might rent a dyno session after I understand the basics of tuning. But it is not worth my money to try and learn with it that far away. I might waste all my time trying to figure out the little things. Once I have my understanding better I will make the drive.

I have the HP Tuners MPVI pro. And I have done enough stuff with it I know where everything is at. I know how to pretty much use the VCM scanner. I have setup my scanner with the PIDS that I have read most people use. I have learned how to put the ECU in open loop for MAF tuning. But I am not sure if the settings I have made are accurate or not. This is just what I have learned online and I want to make sure I am not spinning my wheels when I might not be in open loop properly. I also need to learn what the data means that I collect with the VCM scanner. I have a good general understanding of everything but putting it to the real world is what I need help with. I am basically ready to jump in and tune, but I am hesitant to just do it. That is why I joined up here. I hope that all made sense.

So if someone could look at what I have changed in my first post to get in open loop and let me know if what I have done is acceptable or not would be great. Also if someone can confirm how I drove to start my MAF tuning to gather the logs and if I am on the right track would be very helpful.



I am bumping this in hopes to getting some help.



Hello there,

I will try to offer some advice by I don't have any direct experience with HP Tuners or your specific applications so i wont be able to give you a step by step guide.

With respect to MAF or SD or AlphaN+D I would think about where you want to be, if you did want to stay close to stock then the MAF is the easiest and simplest way to go but for larger increases in power MAF will be limited and you will benefit more from SD so it could be worth getting on board with SD from the outset.

Road tuning is more than enough for most aspects but you will need a load control dyno to accurately map things such as the ignition timing, injector timing, compensation tables etc. however an accurate wideband uego and a good logging set up will get you most of the way there.

The Zeitronix wideband you have should also have a 0-1v or narrowband output, wiring this to the input of your factory lambda sensor should mean the ECU won't compensate the fuelling and it will essentially be in open loop full time so you can calibrate by logging the wideband signal, you could however loose any engine protection so putting it on a switch and only using it or calibration is advisable.

HPA do have a number of Webinars and courses that will help;


this course should cover any questions you may have and includes HP Tuners worked examples




Thanks Scotty88! I do plan to stay mostly stock until I get better at tuning. I want to get my feet wet with just updating the stock tune and then next start to add bolt ons like intake, upper pulley on the superchager, ported snout, etc. I do have big plans for big HP, but I want to take it easy.

So do I understand you correctly? If I go SD, will that disable the need for MAF tuning? It was my understanding you do one then the other and they work together. I have played around with MAF error and updating the MAF tuning. I have not messed with SD tuning yet.

I have been through all of those courses already once and the worked examples. In the worked examples I noticed Andre did disable a few things to disable the long/short term fuel trims. But the things I disabled seemed a little different. Basically I put the system in open loop to tune the MAF. Is that the correct way?

Is there a way for me to upload my tune and my logs to makes sure the changes I have made are proper?



Bump, I am hoping to get some answers to the above questions. Thx

Hello Barry,

You're quite right in tuning in open loop mode to avoid the CL fuelling fighting back and there are multiple ways to do it.

regarding tuning with SD, HP tuners has a few idiosyncrasies as the OEM strategy uses MAF in in steady state and SD in transient conditions. After a scan on the HP tuners forum the common method is to scale the MAF 1st then disable the MAF sensor to tune the SD tables and the two will work together as before. There is however a software patch that will allow it to run in SD full time and maintain traction control functionality etc. for when the MAF becomes a limitation.

I'ts worth taking a look at the HP tuners forum and elsewhere online as there are multiple SD tuning step-by-step guides for each ECU application that may be helpful.

You can use the attach file option below to upload logs and calibration files if you would like us to take a look.

Thanks Scott! That does help.