2016 C7 Z06 with Maggie 2650, and BTR Stage 2 Cam - Idle surging issue

[gman915us]

Guys,
I've been chasing a big cam idle surge since my car was tuned last year. It happens mostly when the car is cold and you put it in gear. But it also happenes once the car is warmed up and your coming to a stop (usually surges just once then levels out again). The rpms also rev higher then drop in a surging pattern while coasting down any hill with no throttle input. Everywhere else the car runs great and behaves perfectly. Please help! Attached is my tune.

Final Tune From KaizenSpeed.hpt
8 April 2024 Surging.hpl
surging hard 10 september.hpl

[charcoal03silvy]

Have you reached out to the tuner/shop about the issue to see if they can help? That is always my first recommendation.

Title says Z06 but VIN and OS are for a LT car not an LT4.

There's a lot of stuff in there that looks copy/pasta'd from an LT4 file and some of that got screwed up in the process. VVE stuff is completely fubar'd. There's some things I could try to tweak to help sort it out but honestly, in my opinion, it probably needs a LOT of stuff moved back to stock and reworked and the issues would likely resolve with a proper airflow and torque model. If it were something quick and easy I saw I'd make the changes and post it to try out.

I copy/pasta'd some stuff from a similar file to see if it helps you but IMO needs a lot of reworking after determining if this is actually an LT4 or LT1 car with a blower and cam.

gman915us test.hpt

[Alex14SS]

Guys,
I've been chasing a big cam idle surge since my car was tuned last year. It happens mostly when the car is cold and you put it in gear. But it also happenes once the car is warmed up and your coming to a stop (usually surges just once then levels out again). The rpms also rev higher then drop in a surging pattern while coasting down any hill with no throttle input. Everywhere else the car runs great and behaves perfectly. Please help! Attached is my tune.

Final Tune From KaizenSpeed.hpt
8 April 2024 Surging.hpl
surging hard 10 september.hpl

Final Tune From KaizenSpeed Maybe.hpt

try this

[gman915us]

Have you reached out to the tuner/shop about the issue to see if they can help? That is always my first recommendation.

Title says Z06 but VIN and OS are for a LT car not an LT4.

There's a lot of stuff in there that looks copy/pasta'd from an LT4 file and some of that got screwed up in the process. VVE stuff is completely fubar'd. There's some things I could try to tweak to help sort it out but honestly, in my opinion, it probably needs a LOT of stuff moved back to stock and reworked and the issues would likely resolve with a proper airflow and torque model. If it were something quick and easy I saw I'd make the changes and post it to try out.

I copy/pasta'd some stuff from a similar file to see if it helps you but IMO needs a lot of reworking after determining if this is actually an LT4 or LT1 car with a blower and cam.

gman915us test.hpt

Maybe this will help....

2016 C7 Corvette Stingray Built into a Fully Forged Supercharged Z06 Widebody
Engine:
1000HP Fully Forged 6.2L GEN V LT1 (DOD/VVT Deleted) with:
Magnuson TVS-2650 Supercharger with 90mm Grip Tech upper and DSX 9.25 lower (16PSI Boost)
TooHighPSI Billet Low Profile Supercharger Lid
Nick Williams 103MM Throttle Body
RotoFab Big Gulp 5-inch Z06 Cold Air Intake
2” American Racing Longtube Headers with 3-inch X-pipe
Gwatney Performance Forged 10.25:1 (Diamond) Pistons
Callies Compstar H-beam Connecting Rods with ARP 2000 Fasteners
ACL H- Series Calico Coated Main and Rod Bearings with Extra Clearance
ARP Heavy Duty Head Studs and Main Studs
LME CNC Ported Heads
BTR .660 Platinum Dual Spring Kit with Titanium Retainers and Keepers
BTR Gen V LT1/LT4 Rocker Trunnion Upgrade
BTR Stage II Supercharger Cam with +38%Fuel lobe
Johnson 2116LSR Slow-Leak-Down Link Bar Racing Lifters
BTR Chromoly One Piece 3/8” Pushrods with .080 Wall Thickness
LME Billet Timing Cover with LS3 Solid Timing Gear and Billet Timing Chain Guide
Katech C5-R HD Timing Chain
Katech Dry Sump Racing Oil Pump
ATI Super Damper
ZR1 LT5 Flex Plate with ARP HD Flex Plate Bolts
GM LT4 High Pressure Fuel Pump
GM LT4 Fuel Injectors
DSX Tuning 255LPH Low Side Fuel System
DSX E-85 Flex Fuel Sensor
Cordes Performance LT4 Heat Exchanger with Engine Bay Ice Tank
Lingenfelter EMP high volume 25Amp Intercooler Pump
Dewitt’s Dual 1-inch Core Direct Fit Radiator
Dewitt’s 19-inch 835W Brushless Fan with Shroud
Katech 71C (160 degree) Racing Thermostat
Texas Speed 10MM 30 OHM per foot Spark Plug Wires
P3 OBD2 Digital Vent Gauge
AEM X-Series UEGO AFR ODB2 Wideband with Carbon Fiber Mount
Mighty Mouse Wild 10AN Catch Can

[edcmat-l1]

That's a heck of a build. Too bad the calibration doesn't reflect the quality of the build. These are the kinds of cars I get. After someone spent all their money with some other shop, I get the clean-up work because it runs like dog poop. And it usually comes with something along the lines of "Man I just don't have any more money to spend on this thing".

Sorry for the vent....

[charcoal03silvy]

From what I gather it still has a the LT1 OS/Segments and they just copy/pasted all the LT4 stuff in.. not even setup as a sciap sensor system.

As stated, I think the best path forward is starting from a clean stage with fresh OEM segments, and redoing it entirely. Unfortunately, these newer controllers rely on everything jiving together and if one thing is in left field it can cause completely unrelated undesired outcomes.

[gman915us]

That's a heck of a build. Too bad the calibration doesn't reflect the quality of the build. These are the kinds of cars I get. After someone spent all their money with some other shop, I get the clean-up work because it runs like dog poop. And it usually comes with something along the lines of "Man I just don't have any more money to spend on this thing".

Sorry for the vent....

I built the car myself as a gift from retiring from the Army after 38 years. My OCD wanted to make sure that side of the build was right with the best parts complimenting the direction I wanted to go. The car idled perfect with zero issues on the base tune that was given to me, but had issues immediately after getting dyno tuned. Car runs great everywhere else, just the idle and down hill decelleration is jacked up. I have zero issues spending the right money for the right tuner, to make sure the car runs right.

IMG_0195.JPGIMG_0193.jpg

[GHuggins]

Going on the previously mentioned, you're going to want to make sure you have a sciap installed, wired in and the background sciap tables installed as it does require about 4 background normally 0ed out tables to be populated for the boost changeover and activated for the 2650 using the lt5's tables. That alone will clean up a lot of the startup, take off and light throttle driving issues. You're also, since its a car going to better off to actuate the supercharger settings in general. That part can be worked around depending on how you're currently referencing the iat reading, but it is best for the throttle calcs to use both the MAF's iat and post boost iat's readings. It all goes into it's air density calculations.

[1scls1z]

Fwiw I am just a hobbyist, but I have tuned several LT1 based platforms with superchargers installed that do not have SCIAP sensors and they drive fine. Do they drive 100% stock no, but they drive perfectly fine imo. I feel like trucks are more finicky with this vs cars for some reason. That being said, I would probably follow Gregs advice because he knows more about this than me. Just sharing what I have experienced. My friend has a 2016 Camaro SS A8, forged LT1, BTR stage 2, P1x @ 13psi that made 817whp. It could use a converter being it's right on the edge of pushing on the brakes but overall it drives good...like stock no. What I have found is that often times too much is done to the external load and torque reserve table. I have better luck leaving it stock and just rescaling the axis by the amount you increase the target idle. Also the throttle open/closing rate table will cause idle to hang if they are just maxed out. It sounds to me like someone that knows what they are doing needs to take the car for a couple days on do some tuning on the street. Greg is right that we don't have all the tables we need, but you should still be able to get the car to behave better than that as is. And you could probably get it 100% perfect if you did have the SCIAP sensor installed and tuned by him.

[GHuggins]

Cars are easier just because of how a lot of the settings are already like an lt4's from the factory including a lot of the throttle tables. They just don't have a lot of them populated or activated to work with boost such as the sciap settings as they didn't have the sciap in the first place. Plus everyone thinks you can just throw a sciap on one and be ok. This just isn't the case because a lot of the sciap settings in general such as their characterization tables are missing. Will found these a while back and I guess didn't realize it. After putting those in and activating them you can get really good light throttle control. I even had a zl1 with a bigger blower bouncing on take off due to a multi disc aggressive clutch grabbing and all I did was change those tables to be more in line with a 2650's and all of the throttle bounce went away. There are a lot of calcs playing into how these things control throttle. Can you tune one without them and be ok. Sure depending on the setup and how big the blowers are and how bad things are skewed. I've seen horrible looking tunes run just fine... I just prefer to have more things that should be there for correct torque and throttle control more in line with how the OE had them for the same like setups. There are plenty of decent tuners on here. I know Jason does a ton of LT1 and LT4 stuff too...

[gman915us]

Cars are easier just because of how a lot of the settings are already like an lt4's from the factory including a lot of the throttle tables. They just don't have a lot of them populated or activated to work with boost such as the sciap settings as they didn't have the sciap in the first place. Plus everyone thinks you can just throw a sciap on one and be ok. This just isn't the case because a lot of the sciap settings in general such as their characterization tables are missing. Will found these a while back and I guess didn't realize it. After putting those in and activating them you can get really good light throttle control. I even had a zl1 with a bigger blower bouncing on take off due to a multi disc aggressive clutch grabbing and all I did was change those tables to be more in line with a 2650's and all of the throttle bounce went away. There are a lot of calcs playing into how these things control throttle. Can you tune one without them and be ok. Sure depending on the setup and how big the blowers are and how bad things are skewed. I've seen horrible looking tunes run just fine... I just prefer to have more things that should be there for correct torque and throttle control more in line with how the OE had them for the same like setups. There are plenty of decent tuners on here. I know Jason does a ton of LT1 and LT4 stuff too...

GHuggins,
So your saying I should order the SCIAP harness and sensor for the Magnuson 2650, pin it into the ECU, then find a good tuner to assist in activating, and sorting out the tables in HP tuners? Also should I just purchase the stock LT4 SCIAP sensor for the maggie or do you recommend another?

[gman915us]

Cars are easier just because of how a lot of the settings are already like an lt4's from the factory including a lot of the throttle tables. They just don't have a lot of them populated or activated to work with boost such as the sciap settings as they didn't have the sciap in the first place. Plus everyone thinks you can just throw a sciap on one and be ok. This just isn't the case because a lot of the sciap settings in general such as their characterization tables are missing. Will found these a while back and I guess didn't realize it. After putting those in and activating them you can get really good light throttle control. I even had a zl1 with a bigger blower bouncing on take off due to a multi disc aggressive clutch grabbing and all I did was change those tables to be more in line with a 2650's and all of the throttle bounce went away. There are a lot of calcs playing into how these things control throttle. Can you tune one without them and be ok. Sure depending on the setup and how big the blowers are and how bad things are skewed. I've seen horrible looking tunes run just fine... I just prefer to have more things that should be there for correct torque and throttle control more in line with how the OE had them for the same like setups. There are plenty of decent tuners on here. I know Jason does a ton of LT1 and LT4 stuff too...

GHuggins,
So your saying I should order the SCIAP harness and sensor for the Magnuson 2650 (I see where the SCIAP sensor should go on the front of the Maggie), then find a good tuner to assist in activating, and sorting out the tables in HP tuners? Do you have the link to the harness and sensor I should get? I received the MAF/IAT break-out harness with the maggie kit that connects to the MAF and the IAT sensor at cylinder #2 intake, and I also received the extention cable to the MAP at the back of the SC. But didn't get anything for the SCIAP in the kit.

[GHuggins]

GHuggins,
So your saying I should order the SCIAP harness and sensor for the Magnuson 2650 (I see where the SCIAP sensor should go on the front of the Maggie), then find a good tuner to assist in activating, and sorting out the tables in HP tuners? Do you have the link to the harness and sensor I should get? I received the MAF/IAT break-out harness with the maggie kit that connects to the MAF and the IAT sensor at cylinder #2 intake, and I also received the extention cable to the MAP at the back of the SC. But didn't get anything for the SCIAP in the kit.

PCMofNC is the only company I know offering the sciap kits with directions to wire it in, only once again there are some missing background tables for it to work correctly and you can't just flip the switches like their directions state. IF you do the iat for a car's OS and set it up to be like an lt4's - this does require flipping some switches and Will will be who you're going to need to talk to for all of the missing tables and so on - but you're going to have to remove the iat harness from whipple and redo it. Basically you'll change its wiring to go straight to the ecm on top of going back to using the MAF's iat. The cars are the only ones you can do this to simply because they don't have an ambient air temp sensor or an OS that uses one. You can technically leave the iat how you have it and not flip the supercharger equipped switches and treat it like a truck's OS. This is how whipple and most people out there handle them.

I'm doing two swaps right now. One's running the lt4's OS and one's running the truck's OS, so they're both wired differently, but both ways work and will use the blowers iat reading for iat spark adjustments.

[gman915us]

Final Tune From KaizenSpeed Maybe.hpt

try this

Alex, I looked in the compare file but I can't find what was changed between my Kaizenspeed tune and your "maybe" tune. Can you please elaborate? thank you.

[gman915us]

GHuggins,
Should I also get the barometer break out harnes from DSX to ensure my car can adjust at different altitudes? From what I was told, they typically disable the barometer when you add a sc to an LT1.

[edcmat-l1]

Baro break out harness is used primarily in centrifugal SC applications where the MAF is pressurized.

[gman915us]

Thank you edcmat-l1

[gman915us]

Even though Cordes said the SCIAP was unnecessary to tune the car (LT1), I ordered it anyway since my issues are directly related to idle, deceleration and off idle drivability. I want to get it installed before taking the car down to them next week to get the tune done right, so I have a solid working base to easily make any future adjustments if necessary. Thank you everyone for your help in resolving this!

[Ben Charles]

That's a heck of a build. Too bad the calibration doesn't reflect the quality of the build. These are the kinds of cars I get. After someone spent all their money with some other shop, I get the clean-up work because it runs like dog poop. And it usually comes with something along the lines of "Man I just don't have any more money to spend on this thing".

Sorry for the vent....

Ed I feel you… when that happens.. I always ask them why would it be fair to fix it for cheaper?

[GHuggins]

Even though Cordes said the SCIAP was unnecessary to tune the car (LT1), I ordered it anyway since my issues are directly related to idle, deceleration and off idle drivability. I want to get it installed before taking the car down to them next week to get the tune done right, so I have a solid working base to easily make any future adjustments if necessary. Thank you everyone for your help in resolving this!

They have to be able to put in the background tables for the SCIAP. Otherwise it won't work or do what it's supposed to do. Just recently been discovered that it can cause emissions test to not pass too FWIW.