FitFam

Its not a 1970 Dodge, they hold their own for larger cars. 24.7 on the Figure 8 (MotorTrend) is no slouch. There are people tracking the car, yes its not a Z06, but the point is you can run the crap out of it and not overheat.

Chrysler's torture testing revealed that the intercooler system can keep inlet air temperature below 140 degrees under the most extreme conditions. Engineers say that after 20 laps on a 3.1-mile road course in 100-degree heat during testing, the Hellcat's horsepower didn't drop one bit. Other durability tests included a 24-hour road-course run and 125 consecutive dragstrip launches. On top of that all production Hellcat engines are subjected to a 42-minute dyno test before shipment.

My point in all this is there are way to many people experiencing real heat issues with the Z, tracking or not, driving up a mountain or what have you. That in my opinion requires a fix from the manufacture period. I feel bad for those that have purchased these cars for whatever purposes and are getting the run around from GM. I am a long time GM guy, I want the Z, I have my order in. They are one of the hottest cars on the market today, but they need some tweaks. I take my hat of to Dodge for building an amazing car and its does it very well. This is my very first Dodge. I have been looking in the forums and people are not having issues with the Hellcat, the same is not true in the forums here in this site.

I wish everyone all the best with their cars and hope GM will step up and fix what needs to be fixed. It will only benefit them long term.

wilyvet

When was the power steering fix implemented in series production? ... for those of us having Z06s built more recently than April.

SBC_and_a_stick

I overheated on both 91 octane and 100 octane in the same day. It doesn't make a noticeable difference, if any, for me.

Catchmeifyoucansam

Did you notice consistency in power from beginning to end of the run session? Notice a top end speed increase? Change in lap times?

Cyclone09Z06

Dave I also run 195 on the street, never had an issue on the street. The oval cap deal is a separate issue all together. As I reported GM did replace my fuel pressure rail switch even though I had no code. I am running VIR with the NCM next Monday and I am hoping I can run a full session like Sean does. If I am able to than this could be part of the solution for the early produced cars. It does appear that the early cars have the biggest problem

Higgs Boson

octane is not going to help an overheating issue. it can help lower combustion temps but not coolant and oil temps when you are hammering around a road course....

i'd say correlation is not causation.

Catchmeifyoucansam

Also, did you happen to check the radiator resivior for the oval shape everyone is talking about? I want to check mine but it's 3 hours away from me

Cyclone09Z06

I think the oval rad cap is a separate issue, I think that you success was due to your Fuel rail pressure switch being replaced or at least I hope so as mine has been replaced as well, we will see!

hyteck9

..very interesting thread.

In my experience, afr contributes to overheating way more than timing. ..so maybe its not completely leaning out... but still fuel = cool.

I would be very curious to know what kind of WOT AFR's are actually being achieved independently of what the ECU 'thinks' is going on.

Someone with a C7 Z06 , go slap on a self-contained wide-band data logger (I have and like the FAST unit myself) and see if the computer is confused!

CitationZ06@yahoo

http://www.freshpatents.com/-dt20090312ptan20090064976.php


It is near the end, but every time you get gas "change in fuel levels". The (virtual flex fuel sensor) uses math, temp, fuel tank pressure, bla bla bla to determine fuel type. This gives the car a starting point to determine which map to use. If your virtual fuel type is wrong you will be using to much or to little timing with your fuel choice. The cars that have overheated may have a problem with determining fuel type. Adding E85 sensor may help the computer find the correct fuel, no matter weather you use E85 or not. The truck uses a sensor the vette uses this virtual sensor. This may explain why some cars overheat all the time, some never do. Hummmm are the fuel tank pressure sensor off a little.

hyteck9

I'm pretty sure the cars reporting overheating are running 93 or race gas, not E85. If they were doing so, and the ECU was misidentifying it as E85, the cars would be running richer (cooler) not leaner (hotter).

If all cars running E85 are running hot, you might be on to something there. I'm don't know who all has done so.?

CitationZ06@yahoo

How would it run if you had 93 in the tank but it used the 91 or 87 map?

descartesfool

Exactly. If the car is making 650 HP on track flat out, then it is making about 33% of that in mechanical output, 33% of that out the exhaust pipe, and 33% of that in heat into the radiator and other coolers and drivetrain. No change in octane is going to make any noticeable change in the heat output if the car makes the same average power per lap. If car makes more or less power due to a change in fueling, it makes more or less heat, with percentages remaining about the same.

johnglenntwo

https://books.google.com/books?id=8b...rature&f=false

SBC_and_a_stick

Well, the car started sputtering out of nowhere after my second session with 91 octane. The power came in waves and it was hesitating to give me throttle even at 50%. It wasn't on the track. Just driving back from the dealer to the track. I put in 100 octane and power was smooth after. I didn't notice sputtering the first two sessions, so it is hard to explain if it was low octane that caused it.

Now that I think back on it, it must have been something to do with the car more than the fuel. Maybe my fuel rail sensor or fuel pump acted up. Perhaps mine is on its way out too.

Generally, with 100 octane I don't feel much difference, not in times, nor in power, nor in top speed on the straights. Perhaps as I get used to the car and push for that last 10th I'll start noticing the subtle improvement.

Mine is fine. It takes a few twists on the cap to start hearing the pressure come out of the system. It seals and sits well in the reservoir. I also haven't lost any coolant yet. The cap seems to work as intended.

Higgs Boson

This is only true for Flex Fuel vehicles, of which the Corvette is not. it will read 10% no matter what in the Scanner and the Stoich table is 14.1 all the way across. It is not equipped stock to read any alcohol %. Depending on model year, trucks could be virtual or physical.

In the Vette tune it is listed as Virtual in the Fuel section but that is because there is no option for none. In the Diag section the sensor is disabled (because there is no sensor).

SBC_and_a_stick

This is my belief as well. The computer may pull timing with 91 octane. If so a slight loss of power should occur. Other factors impacting coolant levels will overwhelm this small change in power.

Throttle position and gear selection are likely 1000 times more important for coolant temps. Here we are talking about a few HP difference at 100% throttle. If there is a loss of HP due to low octane, I gather the engine will produce less heat not more. Either way, it can only be a negligible amount.

johnglenntwo

http://www.deseretnews.com/article/5...ne.html?pg=all

AORoads

That's what I thought when I read overheating and poor cap or neck design.

rsilver

Would be nice to know if this fixes overheat on power steering and is for real. What was done to fix it?.Is there really an ECM patch to fix it? TSB? ......bob noob