Car is an '07 Z06.
What are the changes that normally need made to the tune when adding long tubes with hi flow cats?
I have HPS Tuners Pro and had a custom dyno tune done by Ed Hutchings previously. I plan to have the car dyno'd and send the logs to him but was curious what changes are almost always needed when doing the headers?
Thanks in advance!
depends on your o2 sensor placement
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Although I'm pretty new to the tuning side of modding, I've built several 5th gen Camaros, and when adding long tubes, I've had to go into "engine diagnostics", "dtc's" and for the P0300 (engine misfire detected) line, set it to #3 - no error reported. Wish I was more familiar with which ecu's are used in which vehicles, but for the e38's, moving the 02's to any distance from OEM, the engine will occasionally detect a random misfire, which triggers the "Service Stabilitrac" message on the DIC.
Someone please correct me if I'm wrong, but the ecu calculates the time from injector pulse to cylinder fire to 02 read, and if the 02's are moved, that calculation time is off, which could trigger a misfire.
I haven't noticed it much on cars with just headers, but every single one with a bigger cam has done it.
Also, depending on your high flow cats, depending on how well they work, you may start getting MIL's for post 02 codes. There's several of them in the DTC's to go through, but on boosted cars (can't keep cat's alive for some reason), we usually run cat-less, and go through the DTC's and anything listed as "H02S with a BANK 2 on it, set those to #3- No error reported.
Soemone please correct me if i'm doing something wrong, but this has worked well for me to keep the MIL lights off and eliminate the Service Stabilitrac message..
It towards the end of the headers. In front of the cats. Thanks!Originally Posted by SultanHassanMasTuning
Cool thanks for the explanation Nate! Ultimately I'm not doing the tuning alone but figured that there was a standard number of changes needed. I'll watch for the codes that come up.
Anyone else have any info to add?
In Closed Loop there is a delay from the time fuel trims are adjusted till the O2 sensor reads again. If you move the O2 sensor 2 feet? Well the STFT Vs airflow delay needs to be increased or it causes all sorts of issues like up down fuel trims, surging etc...
Where exactly is this table? I'm very familiar with adjusting this for Fords with different software, but I could never find the table for it when tuning GM vehicles with HPT.
I haven't found it either in HP Demo. Was thinking of purchasing HP Tuner since many parameters like this are missing from EFI Live. Other's like O2 sensor high and low to go with switch points, Proportional gains etc...
I'll check my latest version of HPTUNERS to see if it's there somewhere. Thanks for the replies!
I believe the misfire settings are in the engine diagnostics>general tab, but I don't have it handy right now to check, but I'm pretty sure I've seen the misfire settings there?
I might be over thinking this, but I've had the same issue with several 2010 Camaro's I've built within the last couple years. The cam grind that I've been using is fairly large at 621/624, and all have thrown the "service stabilitrac" message at one time or another. After figuring out what was causing it, I've been disabling the p0300, and it's been working just fine, but the question of adjusting the delay on the 02's has me thinkning...
When the factory ecu detects misfire, it is calibrated to be able to detect which cyl is the offending cyl, as noted when scanning it has shown which cyl it detected. It seems logical to me that the misfire detection system is calibrated using the oem exhaust manifolds, which are not equal length, so by adding an equal length long tube header, there really wouldn't be any way to retain it's ability to detect misfire correctly anyway, even by adjusting a delay? Am I understanding the process correctly here? Simply adjusting the delay wouldn't be accurate enough without some serious calculations to get the distance just right, and with an equal length header it wouldn't work anyway as the pulses enter the collector completely different than they do on the oem manifold? It would seem to me that to adjust it so it's correct, it'd have to be completely re-written to correctly identify which cyl, and correctly calibrated to the exact length of the header? Someone correct me here, or does the delay setting simply make the ecu more "numb" to the event, which in any case, why not just change the p0300 when adding long tubes?
If I'm doing something wrong by only changing the p0300 setting, please let me know. A number of the cars I've made this adjustment to are supercharged cars with the long tubes and big cam, and I'd hate to be masking a potential issue with something?
I believe the misfire diagnostic primarily uses the time between signals from the teeth on the crank trigger wheel, not the O2 sensors.
Usually the big cam is an issue at idle for all sorts of reasons. One is O2 sensor Proportional gains, without it it's impossible to tune idle Closed Loop. "Base proportional O2 gain for engine idling" = "Defines the base gain for generating the O2 proportional correction terms when the engine is idling." That is just the idle proportional gains. Calm them down for off idle and it's easy to get fueling dialed in throughout RPM range.
Right on the long tube headers, how does the misfire detection know the O2 sensor has moved 2 feet? It's reading the wrong part of exhaust flow. It's not numbing the PCM to anything! It's just giving it the correct information!
This was known many years ago in OBDI tuning and known as INT Delay Vs Airflow. It is an O2 setting... but like I said many of these are none existent in OBDII tuning software. All sorts of tricks have been invented to cure the issue. I'm not sure why OBDII software does not have them, or found them, or maybe it's a scare to put adjustments to emissions devices? Maybe it's a secret that only the top tuners have? Not really sure why
Look for a parameter like "O2 Airflow rate factor = The airflow rate factor represents the transport delay for the exhaust to reach the O2 sensors."
It's never an issue with CARB approved headers and if you look at them the O2 sensor hardly moves if at all...
I just got a chance to try a privately written definition file that had all these parameters defined in a highly modified 2001 Camaro. It was OK when I tried with EFI Live. But when done with all the needed parameters I am used to working with the difference at start up, idle and driving was amazing! Drove like a factory car. No tricks, no DTCs disabled, no Open Loop, no headaches, no surprises, all fuel trims in order all the time.
Is it this table?
These two tables affect the % fuel needed for proper closed loop response and start the STFT process
Closed Loop Proportional Base vs. Airflow Mode: This table returns the base proportional % fuel change. Proportional base rate table is the primary amount of fuel needed to drive the closed loop fuel control into oscillation. Proportional fuel acts like an on/off switch to keep the fuel moving around the current O2 Rich/Lean vs. Mode table set point. The values on the Proportional Table add or subtract to the base fuel rate depending on the previous fuel condition (i.e. if rich then switch lean, if lean the switch rich). The amount of fuel to add or subtract increases with the airflow mode and should be based on injector size and % fuel switching needed.
Closed Loop Proportional Gain vs. O2 Error: This table returns a multiplier value for the increase/decrease of the base rate table. A multiplier value of 1.000 will have no effect on the proportional base rate. If the difference between the current O2 reading and its desired value from table O2 Rich/Lean vs Mode (the current Fast O2 error) is large the VCM will need to change the proportional fuel a lot. If the error is small, it should change it only a little to continue oscillation without undershoot or overshoot. Undershooting will cause the Closed loop fuel to become sluggish or miss the current O2 Rich/Lean vs. Mode table set point. Overshooting with cause the engine to vary excessively in RPM.
That looks like the 2 I described earlier!
I dont believe "Closed Loop Proportional Gain vs. O2 Error" exists for E38 PCMs in HPT atleast not for 2007 Z06 or C6, but I do see it for 2008+
I believe 2007 uses Fast 02 filter coefficient instead not in HPT but in other editor
"O2 Airflow rate factor = The airflow rate factor represents the transport delay for the exhaust to reach the O2 sensors."
you need to increase by 5-10% this table if you are experiencing issues...because of the distance increased from stock head to O2 sensors also the transport timing has been affected...
Where is this located?
Inquiring minds want to know.
Doesn't exist on E38s.
There are transport delay features but they are not what "ingsteve" mentioned above. In my other software I use, I have something similar : "Closed loop proportional term gain vs. airflow mode lean & rich" tables, which are related to the "closed loop proportional / airflow mode" except the tables in my other software alter the gain not just the base.
The only transport delay features the E38 has is integrator delays vs. airflow mode for rich and lean.
The other is the fast o2 coefficient table, I found that one made the biggest difference, also not in HPT or EFI Live, but in my other software.
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