2015 Corvette Z51 A8 LT4 Supercharger CamStage2 Headers HPFP - Need Help - Runs Bad

[djyankees31]

Hi All,

2015 Corvette Z51 has the following:
LT4 Supercharger with 2.31 pulley
LT4 Injectors and Fuel pump
BTR Cam Kit Stage 2 with delete
BTR Forged Pistons
Halltech CAI
Headers Catless
Granatelli Intercooler HX Expansion Tank
BTR 160 Thermostat
Catch Can
nGauge
xPipe Catless
O2 wideband installed.

Just got these mods completed on my 2015 Corvette Z51. However, it's not drivable in it's current state. With throttle and boost the car cuts out losing power.

I've driven it in automatic mode and manual mode with the same results. Even in manual mode, doing a pull in 3rd or 4th gear the car cuts out and surges under boost. It does the same with Traction Control On or Off. The dash and PDR doesn't display any traction control engaged while the car in losing power or surging or whatever is happening.

Also, in 7th and 8th gear the car is super sluggish just cruising around. Sounds like knocking or pinging under slight load. However, there's no KR in the logs as the sensitivity was changed. But changing it but to stock KR and misfire settings showed KR and misfires.

Monitoring Lambda with O2 wideband seems to be all over the place maybe that's how it works with cam. Just don't know.

Getting about 9 mpg city and 16 highway with these mods if this helps.

I've compared the tune with the stock tune and a stock tune from a Z06. But since I'm not a tuner, I don't know if the issue is with torque managements, timing, airflow, or etc.

The Corvette dyno around 670 rwhp and 640 ft/lbs

Attached in the current tune and a logging session of cruising around with a few pulls.

What do you see as obvious issues with the tune that I can maybe try myself or suggest to the tuner?

Thanks for any feedback.

17-11-16 15-39-57.hplHPTuners_DataLog_Capture.jpg2015 Corvette Z51 A8 LT4 Supercharger CamStage2 Headers HPFP.hpt

[johnny_boii]

Did you completely delete the VVT or did you get the limiter? If you completely deleted it then change the camshafts to 0 to disable it instead of just zeroing the tables.

The tuner somewhat copied the zo6 torque table but you're making more power than a stock zo6 so that could be causing problems.

Your IAT is higher than anything I've ever seen before, that's definitely taking away spark which could make the car sluggish.

Your knock sensor settings seem odd to me. Every cylinder is set to 10 across the board. Neither a stock zo6 or stingray are set up like that. That could be why it sounds like it's knocking but the scanner doesn't show it, I've never changed the settings for them so I'm not exactly sure if that's beneficial or detrimental.

I'm no where near as experienced as some of the guys on here but that's what stands out to me.

[djyankees31]

Johnny_boli,
Thanks for taking the time to look!!! The builder installed a complete stage 2 cam kit that removed the VVT.

The tuner has sent me a revised tune that did increase the torque which helped it from being removed so dramatic. However, the throttle and boost both are immediately decreased like a yo-yo.

The engine actually sounds bad to me and I'm definitely concerned. I'm not a tuner but I can't image why the knock sensor settings would be changed.

There's also multiple cylinder misfires too.

I've asked about the IAT but haven't received an explanation why it gets so hot so fast.

Attached is the latest tune made with beta version and logs.

Thanks again for the feedback.

[johnny_boii]

I can't open the tune file for some reason

[djyankees31]

The tune was created with a beta version and I downloaded 3.7.573 beta to be able to apply.

The tune didn't change much exact for some of the torque values. But the Corvette still has the same issues.

[paulsmithsr]

who is your tuner its very bad a lot of stuff wrong

[johnny_boii]

2017-11-23 (2).png

So no one else gets confused like him. The tune on the corvette was NOT DONE BY ME!

[djyankees31]

who is your tuner its very bad a lot of stuff wrong

I don't want to mention the shop and tuner at this time. The shop is well known and the tuner is an active member of the forum. I want to give them a chance to make it all right.

I just want a working car that's not going to blow and runs smooth as butter for many years. I paid a lot $$$ for the build and tune.

Yesterday, I changed the KR sensitivity and misfires back to stock settings. I did a simple drive for 10 minutes with logging. It's so upsetting and scary to see the all the cylinder misfires,KR, and O2 errors. Now I know why it seems like it's running on 3-4 cylinders and 9 mpg.

The tune seems like a very bad job of cutting a pasting from other tunes without doing anything specific to my build.

Thanks for looking guys!!!! So much appreciated!!

[djyankees31]

who is your tuner its very bad a lot of stuff wrong

Would you mind listing some of the serious issues in the tune as to help me and others that get tunes as this one.

[paulsmithsr]

first thing high timing and low timing are wrong gonna blow up ---the low timing is higher then the high

[Ben Charles]

If your getting misfires and 02 problems, I would look there first!! Have you pulled plugs to look at them??
Didn’t look at the tune, but if it really runs that bad, it could be non tune issue

[djyankees31]

Some more info:

Please see the latest data log and captures histograms. There's so many misfires happening all the time at every RPM. There are KR issues under light load and WB O2 errors everywhere too.

When I picked my Corvette up, I watched as they did a dyno run.

After the dyno run, while they were getting the car ready they changed the spark plugs. After changing the plugs, I'm sure they didn't do any new runs or take it for any substantial driving. Shortly after I took the car and headed home. I knew it seemed weird but I attributed it to me not being used to a cam stage 2 car in traffic for 1.5 hours. However, once I got out of traffic and cruising the interstate the corvette seemed to struggle just cruising at 60-65 mph.

So outside of a bad tune, I wondering if the spark plugs that were put in the car right before I left are causing the misfires and maybe some of the other issues.

[paulsmithsr]

Any news or help ?

Some more info:

Please see the latest data log and captures histograms. There's so many misfires happening all the time at every RPM. There are KR issues under light load and WB O2 errors everywhere too.

When I picked my Corvette up, I watched as they did a dyno run.

After the dyno run, while they were getting the car ready they changed the spark plugs. After changing the plugs, I'm sure they didn't do any new runs or take it for any substantial driving. Shortly after I took the car and headed home. I knew it seemed weird but I attributed it to me not being used to a cam stage 2 car in traffic for 1.5 hours. However, once I got out of traffic and cruising the interstate the corvette seemed to struggle just cruising at 60-65 mph.

So outside of a bad tune, I wondering if the spark plugs that were put in the car right before I left are causing the misfires and maybe some of the other issues.

[djyankees31]

Any news or help ?

The corvette is headed back to the shop today via trailer. They think it might be a header gasket leak.

I'm expecting, when it's returned all the issues will be resolved, running smooth as butter and powerful. That would help add some of the excitement back that's been lost over the last 5 weeks.

But, I'll be logging with every drive for the first few weeks and will posts some of the logs.

I'll also post the tune.

If it's not right, I will definitely be asking for some help!

Thanks

[veee8]

Lot's of people out there willing to help you if they can't get it right. I have my doubts that a header leak will correct your issues though.

[djyankees31]

Lot's of people out there willing to help you if they can't get it right. I have my doubts that a header leak will correct your issues though.

Thanks! I do feel better knowing I have this community that's willing to help!

Whatever the problem, as I've question that too multiple times, I'm expecting them to fix it as the engine was rebuilt by them adding the cam kit, springs, rods, lifters, forged pistons, blower, intercooler, and etc.

If it turns out to not be ideal, I was already leaning toward RPM Motorsports since they have a great reputation and fairly close.

However, this shop also has a great reputation but isn't close. I'm believing they will figure it out and make it right based on the $$$ spent and work performed.

I'm hoping to have the corvette back within a week with a great build story.

I'm just interested in the final outcome as everyone or shop deserves the chance to make it right. That's the reason I haven't mentioned the shops name. At this point, I don't want to even entertain any different outcome.

Thanks again.

[bfd811]

I second Chris on the header leak. Some incorrect fuel trims... sure... The stuff you are experiencing? Highly unlikely. I wish people could just be honest and just say, "Hey, We're extremely sorry your car isn't performing well. Please allow us to make it right."... Rather than try and pawn it off on "quick fix" like leaky manifolds. People fail, as do parts. Coming forward and taking it to the chest is what counts in my book. I really hope they're able to make it right for you, but if not... I'd let them RPM boy's tidy her up for you. I have absolutely no doubt Chris will get you right where you need to be. His calibrations are spot on, every time.