ooldguy93

Just ran my 2nd track day ( 85 deg. ) with my ( new to me ) '16 Z06

I've got 50+ years W2W and open track experience in many kinds of cars

Car seemed to run well in the AM - faster then other C7 Z's and even with 2 ZL1 1LE Camaro's on the straights. The Camaro's were faster in the corners due to them being on Hoosiers instead of 888's

In the PM I struggled to " inch up " on a well driven STOCK C5 Z
( 355whp ) on the straight's. He's a 15 year track pal

My C7 Z didn't " miss ", ran smooth, but, felt " flat " compared to the AM sessions

240 water and 320 oil / no dash messages

What does " Limp Mode " feel like ?

thebishman

Well the car was pulling loads of power since it was on the cusp of going into limp mode with those high of temperatures.

I’m assuming you car is an A8? If not, get the secondary water radiator installed and you’ll control the engine oil/water temps in any M7 driven sanely.

Bish

ooldguy93

just finished installation of the " 2nd rad " and received the G-Speed I.C. bleeder yesterday

I'll be running an SCCA Track Nite on Tuesday as a test session before Road America

My car is an M7

My goal is to get the car back to what it could do on my first track day this season - 50 deg. and dry, ran several sessions " nose to tail " , back and forth, with a Viper ACR in the Advanced Group. The most fun day this year !

davepl

There's no "subtle" limp mode that causes you to slowly lose power or anything like that. Sure, it pulls some timing/power based on heat, but if you got no messages, you did NOT hit limp mode.

You'll generally see three messages, which I cannot recall verbatim:

- Power steering overheated - use extreme caution. This tends to happen first.
- Then air conditioning will be turned off
- Then the car will go into "REDUCED ENGINE POWER" and will tell you so, no guessing.

So, no message, no limp.

I've found that tracking on cold days is fun, tracking on hot days is stressful. 85 is the limit for my A8 car, and that varies by track and driver.

If you have a straight you can coast it and that will help keep temps down lap after lap, as will upshifting to keep the RPMS down somewhat.

Bill Dearborn

Since you have installed the secondary radiator an 85 degree day shouldn't bring your coolant or oil temps that high. I basically have the same setup with my 15Z and can easily run 20 minute sessions in the low 90s with coolant temps running in the mid 220s and oil temps in the mid 270s.

However, I do have an intermittent power loss that can comes and goes. Sometimes it exists all day and sometimes it hits in the middle of a session and is gone 4 or 5 laps later. The malady seems to show a P0300 code indicating random misfires at cylinder #8 and sometimes a P0308 that indicates a definite misfire at cylinder #8 and that lights the CEL. At a VIR event in April I had P0308 with 512 misfires of cylinder #8 so the dealer mechanic replaced the plug, plug wire and coil for that cylinder. A couple weeks later I still had the misfire but it came with the P0300 code this time and only 131 misfires with no CEL. The history reports show the misfires occur at around 5200 rpm and the car doesn't surge like a low speed misfire the power just seems to sag and feel sluggish not respond to throttle input as quickly as when it isn't misfiring. A lot of times a passenger in the car won't know it is happening. When it misfired 512 times the passengers did notice it since there was a definite bumping in power level. The other thing you should know is my misfire occurs whether the ambient temperature is in the 60s or the 90s.

Check for codes even though you may not have seen a CEL. If you see a P0300 with a misfire on cylinders #7 or #8 bleed the intercooler and make sure there aren't any air bubbles in the horizontal line that runs from the fill port to the S/C and be sure the air bubbles at the top of the reservoir are quarter sized.

Last week I received an email from a GM engineer that has been working with the dealership since last year to resolve my issue. Once the misfire had reoccurred I contacted him again and sent these two pictures showing the air bubbles at the top of my intercooler reservoir:





The following is his reply to the pictures:

There should only be two small bubbles the size of a quarter in the coolant bottle. There is clearly more air in the bottle. I recommend the dealer follow the bulletin below and make sure they use the special tools called out.

18-NA-088: Reduced Performance or Malfunction Indicator Lamp Illuminated with DTC P0300 (Engine Misfire Detected) Set After Service or Replacement of the Charge Air Cooler - (Mar 19, 2018)

I made a PDF file of the TSB info he included in the email and attached it to this post.

I am having the dealer do another vacuum bleed on my intercooler tomorrow.

Just so you know, the dealer mechanic had used those tools (released for the ZR1) to bleed the intercooler before I first went to VIR. However, there is no mention in the TSB of how little air has to be in the air gap or in any of the other documentation telling how to bleed the intercooler. The level shown in my pictures is basically what every other Z06 I have checked has (including ones right off the truck from the factory). Both the dealer mechanic and I are getting exasperated with the continual intercooler bleeding which hasn't resulted in a solution.

However, GM engineering has been insisting since the middle of last year that is the problem. They say that too much air in the intercooler will cause cylinders #7 and #8 to misfire since their combustion temperatures are higher than the other 6 cylinders.

As for the high coolant and oil temps a misfire could cause those but make sure your coolant is at least a mixture of at least 60/40 water to antifreeze (stock mix) and that there are no air bubbles. I don't know how much time you spend in 2nd gear coming off corners at Road America but one thing that can keep temps down is to avoid 2nd gear if the cornering speeds are in the low 50s and just use the engine torque to pull you off the corner in 3rd. That reduces the amount of low speed high rpm activity on the engine and may reduce cooling load sufficiently to bring your temps down.

Also, check the intercooler level and talk to the dealer about vacuum bleeding the intercooler if you think it needs it. The procedure may or not help both of us or maybe just one of us. Good Luck.

Bill

ooldguy93

I bled the I.C. with the G-Speed bleeder.

Ran the pump for 10 min. and no bubbles

However, prior to this I used the " gravity method " about 30 days ago :

Remove filler cap and fill to line and leave cap off

Check the next day and it was below the line - fill again to line

Did this for a week and it didn't fall below the line overnight

I'll try cracking the bleeders under pressure

Mr. Gizmo

jlbjr

GSpeed

This is incorrect Dave. With the intercooler pump shutting off, you get a closed throttle scenario, and ZERO messages. I consider this limp mode. Its worthless, and limps along. No check engine light either. The car will regain throttle.



This is the million dollar question. The pump has diagnostic info, but it is not utilized.

Also, believe me when I say that 4 ounces of air will make a difference. When you have the stock radiator/intercooler configuration used, the intercooler temps can reach upwards of 220*F. Imagine this hot air being shed directly into the radiator. It doesnt take a thermodynamics degree to know that if you have 220 water, and 220 intercooler, that the water temp isnt going to cool. We measured air in and air out while developing our system, and even 30* air temp INTO rad makes a large difference. Its the main reason our system has the intercooler outboard, and away from the radiator.


Those of you bleeding your IC systems, please do it cold. Doing it hot reduces the volume due to expansion, and also does not allow much if any pressure build to aid in cavitation reduction.

GSpeed

OP, when the blower system gets hot, you have a significant reduction in ignition timing. from 24* when cold, to 5* before it closes the throttle. We have seen negative timing in some cases.

with such little ignition advance, power output is 350ish hp, hence your C5 friend keeping up.

Its a gradual reduction in power, sadly. Many do not notice.

Mr. Gizmo

Bill Dearborn

I think the only way you get the air out of the system is to use a vacuum bleeder. If it was as easy as continuously running the pump and having a container of coolant plugged into the top fill port I suspect GM Service would do that. The vacuum will release any air emulsified into the coolant and let it be sucked out of the system.

Bill

Bill Dearborn

I agree with the C5 depiction. When I was running the car at the Glen and the power dropped off it would hit the same top speeds on the straights as my 97. The problem is my issue would not stay constant. The last session of the third day the car started running sluggishly going up through the Esses onto the back straight and hitting 137 to 140 mph before braking for the Bus Stop. Right at the same speed my 97 would run through the same part of the track. However, it didn't start doing it until Lap 3 and it stopped doing it on Lap 7. The guy riding with me didn't really notice until I said It just came back while in the middle of the Esses and we hit 152 before braking for the Bus Stop. Car ran fine for the next 5 laps and the session finished.

Bill

ooldguy93

from the ROAD & TRACK road test :

Truth is, the 650-horsepower, 6.2-liter pushrod V8 finds a much happier home here than it does in the Corvette Z06. The Camaro may have to cut a much larger hole in the wind, even with the so-called “flowtie” hollow Chevy emblem in the gaping grille, but the same bluff front that costs the ZL1 several MPH down the main straight of our test track also makes cooling the engine a much simpler matter.

Our two days at NCM featured some remarkably high temperatures for September, but the supercharged 1LE didn't exhibit any of the heat issues for which the Z06 has become a bit notorious. It didn’t even appear to suffer much supercharger heat soak.

ooldguy93

I " agonized " for some time before purchasing the Z06 as the Nürburgring lap times are the same

With employee pricing a new '18 ZL1 1LE Camaro was the same price as a used '16 Z06 ( 5k miles )

Chose the Z06 as I felt depreciation would be greater on the Camaro vs the Z06

We'll see if I made the right decision

360Lemans

Yes high IAT with M7 and especially A8. It blows my mind how forum members that track 2015/2016 Z06 cannot feel the loss of power from AM to PM sessions?? I could only get 4 laps VIR full before full limp mode, so I have not tracked for almost two years now. My wife has tracked with no limp mode issues at all, but she is not pushing the Z as hard. Thanks to LG Motor Sports and Gspeed I just finished my installation of twin coolers.

GSpeed

Thankfully they (LG) started purchasing tanks from us, but be aware of the bleeders on their coolers. The tank design doesn’t lend well to purging the air out. My suggestion is to make them remote bleeders, do you don’t have to remove the bumper to bleed them.

We designed the Gspeed system to be as self bleeding as possible.

Let us know if we can help. Track time is always more enjoyable with more Vette’s out there!

GSpeed

Yes. But not nearly as bad. They needed to be bled, but fine once bled.

Bill Dearborn

Finished getting intercooler bled (or maybe just gave up as the case may be). What a PIA Process. Took car to dealer today for a 4th bleeding of the intercooler. This is the second time the ZR1 Bleeder was used. Here is a picture of the setup attached to the engine:



When the pump is running and a vacuum is pulled you can get a burst of air bubbles that are very small and basically make the coolant look milky. After the system runs for a while the air bubbles get pulled away by the vacuum. However, the amount of vacuum you can pull on the system is limited to some degree by air leakage past the top and bottom seals on tool reservoir. The other thing that happens to make things difficult is when the burst of bubbles comes out they circulate around the reservoir and get sucked back into the system. What we finally did to get the air bubbles at the top of the reservoir reduced was to raise the front of the car by about 2 ft using the lift and switching the pump on and off. We would run the vacuum system at 25 psi vacuum without the pump running and would get some very large bubbles coming out of the system. Then we would turn the pump on for a few seconds and get the burst of small bubbles and turn it off before they got sucked back into the system. Then repeat the process multiple times and check once in a while by removing the vacuum and stopping the pump to see where the air level was. I got there at 9:30 and left at 12:30. When I left the air gap looked like this:



It took a lot of pulls to get it that way and some times we seemed to go backwards. Hopefully, this will address the situation with the misfire. The mechanic told me to take some pictures of the reservoir after my 10 mile ride home and a several hour cooling period to see where the level will finally settle in. I will post that picture if it shows any difference.

Well it has sat in 95 degree heat inside an open garage for 3.5 hours and the S/C is still so hot I can't hold my hand on it for long. However, the air bubbles did change a little. Here is the latest picture showing a little air under the rear hump and even less under the front hump.




Bill

badhabit_wb

Bill that's the least air I've seen anywhere. Mine had less than what you showed earlier but not that little. I use the G-speed bleeder kit and I've started just putting it on at the quick disconnect once the day is over and it cools down. I always get a couple of bubbles when I squeeze and shake the hoses but I haven't had mine die again since I started doing this. I'll find out how it works next week at NCM when we have some real temps to deal with.