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Increasing reliability of C7 Z51 for HPDE

 
Old 09-01-2017, 02:31 PM
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quick04Z06
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Default Increasing reliability of C7 Z51 for HPDE

If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.
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Old 09-01-2017, 07:04 PM
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Originally Posted by quick04Z06 View Post
If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.
AFM actuators will melt the first time you will go to the track. Nothing to worry about, it happened to me during the second 20 minute session. CEL will come on.

Other than that have fun and enjoy, it is a fun track car.
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Old 09-02-2017, 12:19 AM
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Originally Posted by burunet View Post
AFM actuators will melt the first time you will go to the track. Nothing to worry about, it happened to me during the second 20 minute session. CEL will come on.
Now that I think about it, replacing the mufflers with Z06 mufflers wouldn't be a bad idea since it doesn't have afm valves.
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Old 09-02-2017, 06:05 AM
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Originally Posted by four0nefive View Post
Now that I think about it, replacing the mufflers with Z06 mufflers wouldn't be a bad idea since it doesn't have afm valves.
You'll have to connect 'something' to the plugs of those actuators, or the CEL will still come up. I ended up just cutting the actuator part of the exhaust, and left it dangling:
https://www.corvetteforum.com/forums...k-driving.html

Many seem to have purchased the simulator that's being sold by a vendor.
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Old 09-04-2017, 11:49 AM
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You might want to get your wheels cambered as the manual suggests. I did not do that for my last HPDE and got some ugly tire wear on one side - I guess this counts as "melting".
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Old 09-05-2017, 09:20 AM
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Default Track Prep reliability

Mobil1 15W50, Mutol RBF 600 or equivalent high temp brake fluid, adjust tire pressue expect 6-8psi increase. After 24 hr track time change rear diff fluid. Stock brakes OK for your first few times out but then go to a track pad.

Originally Posted by quick04Z06 View Post
If you want to track you M7 Z51 car, what changes/adjustments should I make JUST for reliability's sake for the long haul? I have a pretty good idea of needed track prep generally, but does this car have a few issues you need to take care of to avoid breakdowns, broken bits, melting parts, etc.

Thanks.
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Old 09-25-2017, 04:05 PM
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Originally Posted by X25 View Post
You'll have to connect 'something' to the plugs of those actuators, or the CEL will still come up. I ended up just cutting the actuator part of the exhaust, and left it dangling:
https://www.corvetteforum.com/forums...k-driving.html

Many seem to have purchased the simulator that's being sold by a vendor.
My car is a 2015. Does that simulator work well for 2015 M7 cars as far as you know? Also, can you just exhaust wrap the 6 inches of the exhaust on either side of the AFM module and provide sufficient protection from heat?

Last edited by quick04Z06; 09-25-2017 at 04:51 PM.
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Old 09-25-2017, 04:17 PM
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Originally Posted by quick04Z06 View Post
My car is a 2015. Does that simulator work well for 2015 M7 cars as far as you know?
On a separate thread, Edgyvette stated they no longer carry those simulators. You might need to ask around.
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Old 09-26-2017, 01:19 PM
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Best thing you can do is leave the engine and tune bone stock.
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Old 06-23-2019, 11:52 PM
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I'm currently on my fourth set of AFM valves for my 18 GS A8. My buddy with a 17 GS is on his fifth set. I lost an entire two day event at WGI sitting in a Chevy dealer the first time it happened since I didn't realize what it was causing CEL and major noise (dealer couldn't figure it out at that point either). The down time for having the car in the shop has also been significant. GM sent my friends mufflers and pipes to an aftermarket vendor who applied a thermal insulating coating that was supposed to fix the problem. Was not a fix, they burned out again on the first track day. We run in the advanced HPDE groups with street tires. This car is built and marketed as a track/street car and if GM performed any track testing on the car with A8, they would have encountered the problem during the first 20 minutes or so. Since this is and will continue to be a recurring problem with our cars, and with no apparent permanent fix, has anyone pursued a Lemon Law claim towards a potential buy back?? If I had any idea of this problem initially, I wouldn't have purchased the car.
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Old 06-24-2019, 12:19 AM
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Just remove it from the exhaust stream and let it hang by the side. Mine had never caused a problem with that setup.
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Old 06-24-2019, 09:29 AM
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Proper alignment (I use DSC Street/track)
Track brake pads (I use Carbotech XP12 & XP10)
Proper brake fluid (I use Castraol SRF)
Proper engine oil (I use Mobile 0W40 ESP)
Change diff fluid after the first event, and then every 4-5 events thereafter
Change Trans fluid every 4-5 events.
Inspect wheels, tires, brake lines, rotors, brake pads, wheel hubs, belts, wire harness, oil level, and coolant level before and after each event.

P.S. If you care about the factory warranty, keep the car as stock as possible.
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Old 06-24-2019, 11:49 AM
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Originally Posted by dfettero View Post
adjust tire pressue expect 6-8psi increase
I believe you meant DEcrease... as tire pressure goes up when they get hot - so you need to let some air out at the track.

Originally Posted by GoatHead View Post
Proper alignment (I use DSC Street/track)
How is your inside tire wear using these settings? That's the area of my Z51 that current sees the most wear. I believe this is mostly related to toe but want to go to the dealer with some knowledge.
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Old 06-24-2019, 11:56 AM
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Just sold my 2014 Z51 in prep for the C8, but I tracked it 4-5 weekends a year and did TT a few times. Car needs nearly nothing:

1. Castrol SRF fluid

2. Stock rotors and calipers were used until the stock rotors (the early 2-part cast rotors) finally wore out after 2 seasons. Replaced with DBA single rears and 2-part fronts.

3. Used stock brake hoses w/o issue.

4. Ended up having to pull the dust boots from the calipers after they thoroughly melted and cracked.... expected.

5. G-Loc R12/R10 F/R pads.

6. Trackday alignment (-1.5/-1.2 F/R for street tires, -3/-2.2 Hoosiers)

7. Added a Z06 grill to the bumper and Z06 quarter inlet ducts to feed the trans/diff cooler... that's it... stock coolers stock radiator; zero issues run hard in VIR summer heat. Oil temp max was 266 and coolant was 232 in May, but usually stayed in the low 220s (219-222 usually). This past May was the hottest I'd run the car at 97 ambient.

Oh... if using stock seats don't bother with a harness bar or harnesses. Use the OEM belt cinch feature and get a HNR that uses the 3-point belt... holds you every bit as good as harnesses. If you go race seat, get harnesses.

PS - I bought Edgy Vette AFM sims expecting mine to fail, but they never did.

Last edited by Tool Hoarder; 06-24-2019 at 11:56 AM.
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Old 06-24-2019, 12:55 PM
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Originally Posted by JMII View Post
I believe you meant DEcrease... as tire pressure goes up when they get hot - so you need to let some air out at the track.



How is your inside tire wear using these settings? That's the area of my Z51 that current sees the most wear. I believe this is mostly related to toe but want to go to the dealer with some knowledge.
After 5 events (12 total days) and 4k miles after alignment, I started seeing inside wear in the front tires. I still have 4/32 on the tires, and I am going to use them for one more event.I drive to and from the track and do some street driving on weekends.
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Old 06-24-2019, 01:56 PM
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Originally Posted by GoatHead View Post
After 5 events (12 total days) and 4k miles after alignment, I started seeing inside wear in the front tires.
Thanks - that doesn't sound too bad.

I only got 3 track days out of the stock tires, but they were old (bought my '14 Z51 used) so it wasn't fresh rubber to being with.
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Old 06-25-2019, 12:26 PM
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Originally Posted by GoatHead View Post
Proper alignment (I use DSC Street/track)
Track brake pads (I use Carbotech XP12 & XP10)
Proper brake fluid (I use Castraol SRF)
Proper engine oil (I use Mobile 0W40 ESP)
Change diff fluid after the first event, and then every 4-5 events thereafter
Change Trans fluid every 4-5 events.
Inspect wheels, tires, brake lines, rotors, brake pads, wheel hubs, belts, wire harness, oil level, and coolant level before and after each event.

P.S. If you care about the factory warranty, keep the car as stock as possible.
Diff and trans fluid every 4-5 events is too much. You're not getting but 2 hours of track time per event. That's changing fluid every 8-10 hours of track time. Overkill.
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Old 06-25-2019, 01:03 PM
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Originally Posted by BrunoTheMellow View Post
Diff and trans fluid every 4-5 events is too much. You're not getting but 2 hours of track time per event. That's changing fluid every 8-10 hours of track time. Overkill.
That was based on Richie's recommendations.
Some events are 3 days and others are 2 days. There are 4 20-min sessions per day on average. I had approximately 15 hours of track time in my last 5 events.
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Old 06-25-2019, 02:48 PM
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My supercharged z51 burned spark plug wires twice. Then I added plug boots and that was fixed... These suckers run hot. Stock headers.

Last edited by BrunoTheMellow; 06-25-2019 at 02:48 PM.
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Old 06-25-2019, 02:50 PM
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Originally Posted by GoatHead View Post
That was based on Richie's recommendations.
Some events are 3 days and others are 2 days. There are 4 20-min sessions per day on average. I had approximately 15 hours of track time in my last 5 events.
I see. I was measuring each event as 1 day.
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