Tune required
Thread Starter
Racer
Joined: Mar 2017
Posts: 394
Likes: 46
Tune required
I feel if you want perfect performance and maximum gains from bolt ons on the Z. It needs a good tune and yes this applies for s drop in air filter or cold air induction. I have seen more than enough proof in this forum that this is correct. Car is tuned from factory for stock system.
Advanced
Joined: Mar 2015
Posts: 64
Likes: 18
From: Yorba Linda CA
I feel if you want perfect performance and maximum gains from bolt ons on the Z. It needs a good tune and yes this applies for s drop in air filter or cold air induction. I have seen more than enough proof in this forum that this is correct. Car is tuned from factory for stock system.
on the z06, I've added a BMS drop in filter borla xpipe and a CRP upper pulley kit on the way. Once installed I will be getting it tuned by Terry at Burger Tuning as well.
Thread Starter
Racer
Joined: Mar 2017
Posts: 394
Likes: 46
Racer
Joined: Sep 2012
Posts: 298
Likes: 86
COT kicks in and the LT4 goes pig rich......been there done that.....with bolt ons, stock tune....still at 10:4:1 afr wot......
I would agree tune required to get rid of COT (so you can lean it out) and set up a correct afr for the fuel you are using.
I would agree tune required to get rid of COT (so you can lean it out) and set up a correct afr for the fuel you are using.
Last edited by wagoetzmann; May 16, 2017 at 12:39 PM.
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
COT aside, why don't the oxygen sensor and MAF merely adapt to the increased airflow and change in mixture? Certainly there are limits to what it can adapt to, but within reason it's designed to be able to accommodate smaller changes, no? There are short term and long term fuel trim tables that would get updated, and then so long as it's within their range of compensation, it should "just work".
So why isn't it that simple?
So why isn't it that simple?
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
that OPINION is shared about half at best while both manufacturers say it doesn't with dyno runs to prove it. Yes a tune is better, but obviously not needed for just an intake since hundreds if not thousands have one without a tune and running fine with more power.
Racer
Joined: Sep 2012
Posts: 298
Likes: 86
Maybe it is an open loop versus closed loop thing.....at wot the open loop doesn't have enough time to adjust and needs tables to draw from?
Last edited by wagoetzmann; May 16, 2017 at 02:24 PM.
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Burning Brakes
Joined: Sep 2006
Posts: 931
Likes: 96
From: Canyon Country CA
I think you should tune the Z. You will pick up power and have a safer set up for mods. After all, you got the mods for more power, why restrict it with stock tune. You could even do a mail order tune from Diablo or ECS.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
COT aside, why don't the oxygen sensor and MAF merely adapt to the increased airflow and change in mixture? Certainly there are limits to what it can adapt to, but within reason it's designed to be able to accommodate smaller changes, no? There are short term and long term fuel trim tables that would get updated, and then so long as it's within their range of compensation, it should "just work".
So why isn't it that simple?
So why isn't it that simple?
At least on the 2 or 3 ZO's I have played with and all the other GM ECM controlled cars over the years.
The PCM can correct up to 25%. It wont even throw a code for high or low fuel trims until it gets above 7% correction factors in the LTFTs maybe more.
If you think about it the PCM compensates all the time by its nature. That's it's job. If you take the car to Pikes peak, it runs all day without codes or running lean. You take it to the Bonneville salt flats, it runs all day without setting codes or running rich. Anyone think the addition of a filter or a CAI is going to get outside of the swing from Bonneville to Pikes peak?
No it wont, but folks will argue to the cows come home.
Is a tune good? Absolutely.
Is it mandatory for minor mods? Absolutely not.
However I would recommend an AFR verification with a scan and data log anytime you do any mod. But with a filter change or CAI from any reputable company I wouldn't be concerned. If the computer cant compensate it will tell you within a few miles of driving the car.
Last edited by dar02081961; May 16, 2017 at 05:37 PM.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
You have atmospheric sensors on the car, a bunch of them to measure everything from IAT, manifold temp, humidity, MAF, fuel temp, engine temp boost and on and on. The PCM can compensate for more, is a lot smarter and thinks a lot faster than most folks on this forum give it credit for.
This isn't directed at any one individual but all of us as a group on this forum. Its actually a shame more don't spend time reading and understanding how the modern PCM adjust to changing conditions.
That's a challenge folks. Please do your homework so we can move on.
Folks have been repeating false rumors about the modern PCM over and over for years.
We are obligated to learn and put out the logical truth or as much of it as we can figure out on this forum. Isn't it time we put some effort into actually learning the basics of this system and its limitations......its only been around for 25 years or so.
Last edited by dar02081961; May 16, 2017 at 06:06 PM.
Former Vendor
Joined: Jan 2006
Posts: 797
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From: terry@burgertuning.com Simi Valley, CA
The factory tuning is actually pretty good on pump fuels IMHO. The largest problem is the overly aggressive timing IAT decay, cat over temp mode, fan turn on temps, and basic things that almost every tune addresses. If you've changed the intake and are tuning rescaling the MAF frequency is also a good idea.
Last edited by Terry@BMS; May 16, 2017 at 06:58 PM.
Safety Car
Joined: Apr 2010
Posts: 4,231
Likes: 451
From: Maryland
You are correct and it is just that simple.
At least on the 2 or 3 ZO's I have played with and all the other GM ECM controlled cars over the years.
The PCM can correct up to 25%. It wont even throw a code for high or low fuel trims until it gets above 7% correction factors in the LTFTs maybe more.
If you think about it the PCM compensates all the time by its nature. That's it's job. If you take the car to Pikes peak, it runs all day without codes or running lean. You take it to the Bonneville salt flats, it runs all day without setting codes or running rich. Anyone think the addition of a filter or a CAI is going to get outside of the swing from Bonneville to Pikes peak?
No it wont, but folks will argue to the cows come home.
Is a tune good? Absolutely.
Is it mandatory for minor mods? Absolutely not.
However I would recommend an AFR verification with a scan and data log anytime you do any mod. But with a filter change or CAI from any reputable company I wouldn't be concerned. If the computer cant compensate it will tell you within a few miles of driving the car.
At least on the 2 or 3 ZO's I have played with and all the other GM ECM controlled cars over the years.
The PCM can correct up to 25%. It wont even throw a code for high or low fuel trims until it gets above 7% correction factors in the LTFTs maybe more.
If you think about it the PCM compensates all the time by its nature. That's it's job. If you take the car to Pikes peak, it runs all day without codes or running lean. You take it to the Bonneville salt flats, it runs all day without setting codes or running rich. Anyone think the addition of a filter or a CAI is going to get outside of the swing from Bonneville to Pikes peak?
No it wont, but folks will argue to the cows come home.
Is a tune good? Absolutely.
Is it mandatory for minor mods? Absolutely not.
However I would recommend an AFR verification with a scan and data log anytime you do any mod. But with a filter change or CAI from any reputable company I wouldn't be concerned. If the computer cant compensate it will tell you within a few miles of driving the car.
Last edited by C7/Z06 Man; May 16, 2017 at 10:42 PM.
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
Because it voids the warranty. Why would someone with minor mods want to void their drivetrain warranty? Spoiler....they wouldn't.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
All I have read is 25% and if I recall the earlier ECM's had 20% authority. The information below was written 2 years ago so it should have but may not have been inclusive of the E92 ECM which had been out a year or 2 at that time.
Page 2 is of interest for this discussion.
http://www.autoserviceprofessional.c...for-you?Page=1
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
So given we seem to agree - that the ECM can compensate up to 25% or even 30%, why do people need a tune with a CAI?
I presume it's because it screws up the frequency tables of the MAF (Hz to gm/sec) when the pipe changes and it's no longer calibrated. But I still don't know.
And do most "tuners" really know how to recalibrate the MAF table or are they just making crude AFR adjustments elsewhere to compensate I wonder?
I presume it's because it screws up the frequency tables of the MAF (Hz to gm/sec) when the pipe changes and it's no longer calibrated. But I still don't know.
And do most "tuners" really know how to recalibrate the MAF table or are they just making crude AFR adjustments elsewhere to compensate I wonder?
Last edited by davepl; May 17, 2017 at 01:03 PM.
Race Director
Joined: Nov 2000
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From: CA
2017 C5 of the Year Finalist
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All good info, and over the years it has certainly been Ok to add a CAI without tuning, and one could easily argue that the C7Z has so many innovations that give the computer tons of info, and allow the PCM to better evaluate data, that it can make the proper adjustments.
I will also say that I have spoke directly to the GM techs who created the new tune for the 17, and the range of air flow IS tighter.
I know folks will come on here and say there are only minor differences in a 16 vs 17 tune, but can they see ALL of the entire tune that GM can?
I have a 17, and chose to tune based on my mods. I will also say that MY EXPERIENCE with MY 17 and bolt ons gave me little chose as to weather to keep certain bolt ons and tune and drive the car as I like to, or remove said bolt ons and keep the stock tune/warranty...
I will also say that I have spoke directly to the GM techs who created the new tune for the 17, and the range of air flow IS tighter.
I know folks will come on here and say there are only minor differences in a 16 vs 17 tune, but can they see ALL of the entire tune that GM can?
I have a 17, and chose to tune based on my mods. I will also say that MY EXPERIENCE with MY 17 and bolt ons gave me little chose as to weather to keep certain bolt ons and tune and drive the car as I like to, or remove said bolt ons and keep the stock tune/warranty...
Last edited by jbsblownc5; May 17, 2017 at 01:24 PM.
Melting Slicks
Joined: Oct 2007
Posts: 2,398
Likes: 858
So given we seem to agree - that the ECM can compensate up to 25% or even 30%, why do people need a tune with a CAI?
I presume it's because it screws up the frequency tables of the MAF (Hz to gm/sec) when the pipe changes and it's no longer calibrated. But I still don't know.
And do most "tuners" really know how to recalibrate the MAF table or are they just making crude AFR adjustments elsewhere to compensate I wonder?
I presume it's because it screws up the frequency tables of the MAF (Hz to gm/sec) when the pipe changes and it's no longer calibrated. But I still don't know.
And do most "tuners" really know how to recalibrate the MAF table or are they just making crude AFR adjustments elsewhere to compensate I wonder?
2. The CAI makers claim similar gains from their products (25-40hp).
3. Tunes with CAI's seem to add about 5-10hp on top of the CAI alone.
4. CAI's on top of tunes seem to add about 5-10hp on top of tunes alone.
So this tell us both approaches are making SOME of their gains from the same factor. What would the common denominator be? Boost!
But if you study where each makes its power you will see advantages to both and you would desire both because they make power at different areas on the curve. Airflow (CAI's) tend to make more power at high rpm where extra air is required. Tunes tend to make more power in the low and mid range by fattening the tq curve. And as stated their is some overlap thus diminished gains when the 2 are combined.
Most tuners do know what they are doing. Especially if they take pride in their work.
To answer your question "why do people need a tune with a CAI?" The same reason your would tune a stock car......to optimize the conservative factory tune.
Last edited by dar02081961; May 17, 2017 at 05:37 PM.
Burning Brakes
Joined: Sep 2006
Posts: 931
Likes: 96
From: Canyon Country CA
wrong! show me a case of a legitimate voided warranty claim from a tune. not one with all kinds of obvious bolts ons, headers, NOS and a long duration cam.
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
For some reason they always run through the auction
and are required to be disclosed. I have personally been witness to several vehicles going through the discovery and block process at the dealer level (with manufacturer verification) and countless "Warranty Block" disclosures at the auction(s).And yes, the trims can compensate for minor changes in airflow but that is a band aid to keep it from running dangerously lean or rich temporarily. What most people don't understand is when the trims are off, so to will be spark lead, torque reporting, transmission shifting for autos, and anything else that references a deviation from the expected airflow model and torque model. These aren't 2001 LS1 0411 ECMs anymore.
Mod your car, tune your car if you want it to run "properly." Simple as that.
I feel like we have been though this 100 times on CF.