Father Larry

Does anyone have pics of a new 2017 Z06 that shows the modifications on the hood and supercharger? My car won't be delivered until Feb 13th, and hoping because I waited to order, that the issue will be solved. Thank you.

RFBHD

Do a search there are plenty of pics on here already.

Bill Dearborn

If you aren't planning on tracking the car it really doesn't matter.

Bill

Father Larry

Thank you but it matters Bill.

Dabigsnake

finally tracked my 17 A8 this weekend in 70 degrees ambient. Took 8 hard laps to get to 253* Coolant and 297* oil temp. while manually shifting. I'm pleased with the improvement over my 15 model.


https://www.corvetteforum.com/forums...-sc-cover.html

Father Larry

Thank you very much.

Mad Dog 24

Serious? Your happy with 253 and 297 in 70 degree weather! Makes me feel like my 2015 is doing a dam good job in the 80's and 90's then, thanks!

Dabigsnake

I run pretty close to the street car/ tire record at this 16 turn 2.75 mile track. My 15 Z would overheat after three hard laps. In cool temps, it would just pull timing to kill your runs. I'm happy over what I had. Not convinced of a real full cooling solution for our A8 cars. I should have just gone w the M7, but? I also like to drag race, and this A8 has proven itself there.
I intentionally used 3rd gear in two spots, where I could have torqued it though. I was intentionally running it 10/10. I think I can run 9.5/10ths all day w just 4-5th gears. I was working on tire setup etc. next sessions Feb3-5th. BTW- well prepped Viper ACR couldn't challenge me.

2fastnow

I bet the dealer sold it (your 2015) without a head gasket change to the next sucker. When ever you overheat any car, super high percentage the heads are burnt or the gaskets questionable.

Dabigsnake

GM protects the car by safe mode/reduced power @ around 262* Coolant temp, I believe. Heads warp or gaskets go, it shows pretty soon with drivability issues. water in oil, or in exhaust, or diminished compression at the least. If I were buying a used Z, I'dd certainly want a compression check and leak down done. GM swapped cars with me, so I have no idea what happened to my old '15 model.

SBC_and_a_stick

If both your '15 and '17 were auto, the car's ability to dissipate heat from coolant and oil are the same except '17 will make a tad bit more power when hot, so it will have MORE heat to dissipate. If you saw any improvement in cooling it's likely due to the way you drive or because your '15 HEs were dirty or fins were damaged from use.

A '15 with secondary radiator will cool down way better than a '17 auto.

ajrothm

I would NEVER hammer on a car with ECTs in the 240+ range.... (actually I'd never hammer on a car over 220*)...The 297* oil temp doesnt bother me much, especially with a dry sump system..

But there is no doubt in my mind, going WOT, multiple times in an LT4 with temps at 240*+ is detonating the **** out of it...If you track guys had a laptop in the car with HP Tuners scanning it while you made laps, you would be shocked at what you see. Its a miracle people arent melting engines down. The PCM is having to pull so much timing to keep them alive its not even funny.

I agree in the fact that GM dropped the ball big time on the cooling system in the C7s.. Unfortunately, there is nothing we can do but fix it ourselves. No point in crying over spilled milk.

dar02081961

While I understand the car is pulling timing from those temps it isn't likely to detonate very much, if at all.

The PCM has tables to pull timing based on the temps. The whole purpose of the PCM is to protect the powertrain and safely operate the engine for whatever conditions. The car has temperature limits that will send it into "limp mode" once reached. These limits are set based on a margin of safety that will normally leave the engine unharmed.

If GM didn't believe this was the case they surely wouldn't offer a 100k or 60k mile warranty that isn't voided by track use. A luxury many other supposedly superior vehicles don't have.

Speedforhire

^ this!

We all know GM hasn't fixed anything and no one has really pushed a 2017 Z car in extreme conditions yet. GM simply applied a band-aid to quell all of the chatter. No factory changes to the 17's will help the track rats. The 100 octane tune will help reduce power loss somewhat marginally but nothing oem will reduce the heat issues. Street brawlers need not concern themselves.

SBC_and_a_stick

Just about every track day in the summer coolant gets over 240*. That is with GM's secondary radiator that auto cars can't use, and with the $1,300 Denso core that NASCAR vehicles use for short track. With your rule of thumb this car shouldn't be out on the track in the summer. Not saying I don't agree but I'm saying I paid my $90k plus cooling mods and I'm going to run the car. I didn't get the Z07 to put it on display. I've done what I could to keep it cool, the rest is on GM. Oil gets near *310 at times, it does worry me. I think the optimum range is up to *275 with 50 weight.

I do see a bunch of KR at the track even with 100 octane, and the timing drops about 10*.

No point in crying over spilled milk you say? We got the GMPP second radiator, the PS cooling duct, and the revised SC bricks. Crying got us a lot!

GM did the math and realized they have a good ownership group that rarely stresses the car except with the wax sponge. I think the math works out that it's cheaper to replace 3 engines for the guy who drives and give the other 99 that wax a crappy cooling system.

Mad Dog 24

SBC and all you other track rats here's a good question. We've all heard of a few C7 Z06s blown up with fairly low street miles with obvious mechanical failures. Have any of you heard of a newer Z06 blowing up on the track or just after? I cant say if I remember any although as my wife says you wont remember my name in 10 years!

More interested in fairly stockers popping. Maybe these LT4s are more durable than we all are expecting them to be. Seems every other track day I see a car smoking up its ribs and parked for the day, no C7s!

SBC_and_a_stick

If I did I wouldn't say.

Expect under 30 race hours if driven properly.

ajrothm

I agree man.. the whole situation sucks and GM should have never put the car out like this from day one. Obviously there is major design faults that even GM's own updates don't fix. I'm with you on wanting to actually use your $90k car and not just let it sit in the garage and in parking lots on weekends...It seems the only real "fix" is to spend the $5-6k for the G Speed cooling up grades, as much as that sucks, I think it's a necessity for guys that want to track their cars.

As for the knock, my car in 1/4 mile sprints hits 212* when starting at 160* and pulls 4-5* KR going down the track. So you can imagine if I'm getting that much KR in only a single 1/4 mile pass, and starting out at a low coolant temp, how bad road course cars are going to detonate.

From my experience with C5s, by the time the knock sensors are detecting knock and pulling timing, the engines are already seeing detonation. I've seen it on plugs, broken ring lands etc.

Maybe the C7 knock sensors are way more sensitive for safety but....I still believe that if you are seeing 5-10* of KR, odds are the pistons/rings are already getting beat on..sure it may not "blow up" but, how long will it be before the rings get fatigued? 2-3 track days, a full season, 2 seasons? So in the course of 5 years it's drinking oil, down on power but still running, and people are ok with that since they felt it was "safe" since the factory engine protection nannies were working.

That's not good for me. If I was going to be tracking the car, I would do everything I could to get the temps to 220* or less...run the highest octane I can and scan for knock. If I really wanted to track my $90k that bad, I'd spend the additional $5-6k in cooling mods to protect my investment, YES, that freakin sux but....so does driving around in a bad *** looking car with a clapped out engine after 2-3 years. Just my opinion.

Like you mentioned, GM counted on the fact that 95% of Z06s will never see the track, so all they have to do is build in enough nannies to kill enough power to hopefully keep them alive long enough to make the 3/36k warranty period, after that, then its earning potential...If they have to eat a few engines under warranty in the mean time, so be it...it's still much cheaper then redesigning the cooling systems, recalls etc. just an educated gamble for them.

Bill Dearborn

With the Secondary Radiator my 15Z in low 90 ambient temps is seeing mid 220s for coolant and mid 270s for oil which is fine. Car will slow during the day from cool morning session where top speed at the end of VIR's back straight is 154 Vs 149 in the really hot sessions at the end of day. Best lap times don't change that much as I am more limited by other sections of the track where I can't go wide open anyways and need to pick up my driving game.

Bill

Poor-sha

102 track hours on my stock motor.