Let's see what you guys think about this. There have been several cars including the G37 that are having oil temp problems and overheating when taken to the track compared the 3.5L HR engines these cars use to have. Here is a copy and paste of a sample post and also a copy and paste of a article on what is the cause of it.
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http://www.the370z.com/track-autocross-d...really-bad.html
and
http://my350z.com/forum/2009-370z/414330-370z-has-overheating-issues-on-road-courses.html
Had some mechanical issues at the track today, so figured I'd share with you guys to see if anyone else is having the same...
location: PIR in phoenix, az
Phoenix International Raceway - Trackpedia
conditions: sunny, 70f
event: nasa hpde3... 4 runs about 20 mins each
I'm driving a 370z base model with sport package and M6... no mods so far, other than pulling about 100 pounds of plastic and spare tires... i only broke it in for ~200 miles prior to the event.
Overall, I think this car is a great starting point for a track / race car. It was reasonably fast, but I definitely wanted more out of 4th gear when going onto the nascar straight... I think once I have another few hundred pounds out of the car, and maybe +25hp in tweaks, the power/weight will be better. The suspension was not as stiff as I'm used to but even with stock setup it handles ok if you anticipate the gradual body roll. I definitely found that it was NOT able to hold the line I wanted for example in the carousel at PIR, but I think that'll be fixed with sticky tires.
So, the big issue i had is this... About 10 mins into my first run, I noticed that the oil temperature gauge was pretty much burried at 300f... As soon as that happened, my rev limiter moved from 7500 to 6000... Every time I'd accelerate through a gear it would prematurely cut the throttle at 6000rpm... Was extremely frustrating as it seemed to cut in at all the wrong times and slowed me down overall by at least 10%
It happened in all four of my runs, usually about 10 mins in.
I can only imagine this is going to get worse as I move to stickier tires and tweak the motor.
It gets worse... After the fourth and final run, it dropped the rev limiter from 6000 to 3500, just as I was pulling off the track. I decided to keep the car running after the session to let the engine cool. Tried to drive it home, and every time I accelerated through a gear it just cut the engine at 3500, sending it back down to 2500... I had to shift gears real fast... luckily 6th gear is good for 80mph at 3000rpm, so I made it home. Also, it turned out that after I shut off the car and restarted, the computer had reset and all was back to normal.
So, we need a solution to this ! I suspect Nissan has decided to get very aggressive on the computer parameters for protecting the engine from overheat in order to lower their warranty repair expenses. We either need to get some REALLY BIG oil coolers for this car, or someone needs to figure out how to hack the computer.
Thoughts ? Anyone else had this issue ?
------
And here is the explanation:
Apparently Stillen is working on one for the VQ37 thanks to the G37 guys. Should probably work for the 370Z too I assume?
"TORQUE CUT CONTROL (AT HIGH ENGINE OIL TEMPERATURE)
ECM receives engine oil temperature signal from engine oil temperature sensor.
To avoid VVEL performance, ECM performs the engine torque cut control at high engine oil temperature.
If engine oil temperature is too high, engine oil viscosity will change. As a result, engine oil pressure is
decreased. This control is to control the VVEL operating angle by operating the VVEL actuator sub assembly.
If this control is operated, engine performance will decrease, then maximum engine speed is reduced a little,
for example.
NOTE:
If the engine oil temperature sensor is deteriorated, its characteristic will change.
In this case, the operating temperature for engine torque cut control might be decrease.
Perform Component Inspection of the engine oil temperature sensor to check for the deterioration.
Refer to EC-248, "Component Inspection". "
And Resolute responded to this with:
I think this was to be expected. The VQ37VHR was already known to be engineered with a sensitive eye on oil temperatures, well before the 370Z made it to production. There wasn't much Nissan could do since the G37's release that would indicate the 370Z wouldn't have this problem, except not use the VQ37VHR, and I imagine they need to install it in several vehicles for a certain number of years to recoup their engineering expenses for the new engine's VVEL system.
The VVEL is a fairly complex system, with a relatively high amount of reciprocating mass and multiple linkages. The lubrication demands are very high to ensure Nissan's life expectancy goals are met. The shearing loads and high pressures exerted on the oil dictate a proper viscosity be maintained in order to resist lubrication failure due to these loads. Because an oil's ability to resist shearing weakens as it gets hot and thins out; a phenomenon plotted as a function of viscosity and shear stability known as the Stribeck curve, it is essential that the oil maintain it's specified viscosity at the appropriate operating temperature. This is why Nissan has engineered a fail-safe which limits power until the oil cools back to its specified operating temperature, because at that temperature it should be at the proper viscosity to withstand the high loads of the VVEL system.
Nissan has already recommended a conventional oil with an ester additive (most likely a borate ester) for a TSB with the VQ37VHR. This was designed to reduce noise and ensure proper lubrication at a wider range of temperatures. However, even a synthetic will thin out with heat, and running a high-end synthetic does not guarantee that the thinner viscosity will have the film strength to resist the mechanical pressures exerted on it by the valvetrain's various components.
Like most engines which see racing or track endeavors, increasing the oil viscosity and capacity will most likely be the best solution to ensure proper lubrication at higher temps. There's a reason high-end sports cars like the M3 use a 60 weight oil. Tampering with the oil temperature sensor might very well become a track hound's legitimate option to maintain the engine's power potential, and as long as a heavier weight oil is used, they might be just fine in doing so. Time will tell.
Will (still wishes the 350hp VQ38HR was used in the new Z34 chassis, instead of the VQ37VHR)
-------
http://www.the370z.com/track-autocross-d...really-bad.html
and
http://my350z.com/forum/2009-370z/414330-370z-has-overheating-issues-on-road-courses.html
Had some mechanical issues at the track today, so figured I'd share with you guys to see if anyone else is having the same...
location: PIR in phoenix, az
Phoenix International Raceway - Trackpedia
conditions: sunny, 70f
event: nasa hpde3... 4 runs about 20 mins each
I'm driving a 370z base model with sport package and M6... no mods so far, other than pulling about 100 pounds of plastic and spare tires... i only broke it in for ~200 miles prior to the event.
Overall, I think this car is a great starting point for a track / race car. It was reasonably fast, but I definitely wanted more out of 4th gear when going onto the nascar straight... I think once I have another few hundred pounds out of the car, and maybe +25hp in tweaks, the power/weight will be better. The suspension was not as stiff as I'm used to but even with stock setup it handles ok if you anticipate the gradual body roll. I definitely found that it was NOT able to hold the line I wanted for example in the carousel at PIR, but I think that'll be fixed with sticky tires.
So, the big issue i had is this... About 10 mins into my first run, I noticed that the oil temperature gauge was pretty much burried at 300f... As soon as that happened, my rev limiter moved from 7500 to 6000... Every time I'd accelerate through a gear it would prematurely cut the throttle at 6000rpm... Was extremely frustrating as it seemed to cut in at all the wrong times and slowed me down overall by at least 10%
It happened in all four of my runs, usually about 10 mins in.
I can only imagine this is going to get worse as I move to stickier tires and tweak the motor.
It gets worse... After the fourth and final run, it dropped the rev limiter from 6000 to 3500, just as I was pulling off the track. I decided to keep the car running after the session to let the engine cool. Tried to drive it home, and every time I accelerated through a gear it just cut the engine at 3500, sending it back down to 2500... I had to shift gears real fast... luckily 6th gear is good for 80mph at 3000rpm, so I made it home. Also, it turned out that after I shut off the car and restarted, the computer had reset and all was back to normal.
So, we need a solution to this ! I suspect Nissan has decided to get very aggressive on the computer parameters for protecting the engine from overheat in order to lower their warranty repair expenses. We either need to get some REALLY BIG oil coolers for this car, or someone needs to figure out how to hack the computer.
Thoughts ? Anyone else had this issue ?
------
And here is the explanation:
Apparently Stillen is working on one for the VQ37 thanks to the G37 guys. Should probably work for the 370Z too I assume?
"TORQUE CUT CONTROL (AT HIGH ENGINE OIL TEMPERATURE)
ECM receives engine oil temperature signal from engine oil temperature sensor.
To avoid VVEL performance, ECM performs the engine torque cut control at high engine oil temperature.
If engine oil temperature is too high, engine oil viscosity will change. As a result, engine oil pressure is
decreased. This control is to control the VVEL operating angle by operating the VVEL actuator sub assembly.
If this control is operated, engine performance will decrease, then maximum engine speed is reduced a little,
for example.
NOTE:
If the engine oil temperature sensor is deteriorated, its characteristic will change.
In this case, the operating temperature for engine torque cut control might be decrease.
Perform Component Inspection of the engine oil temperature sensor to check for the deterioration.
Refer to EC-248, "Component Inspection". "
And Resolute responded to this with:
I think this was to be expected. The VQ37VHR was already known to be engineered with a sensitive eye on oil temperatures, well before the 370Z made it to production. There wasn't much Nissan could do since the G37's release that would indicate the 370Z wouldn't have this problem, except not use the VQ37VHR, and I imagine they need to install it in several vehicles for a certain number of years to recoup their engineering expenses for the new engine's VVEL system.
The VVEL is a fairly complex system, with a relatively high amount of reciprocating mass and multiple linkages. The lubrication demands are very high to ensure Nissan's life expectancy goals are met. The shearing loads and high pressures exerted on the oil dictate a proper viscosity be maintained in order to resist lubrication failure due to these loads. Because an oil's ability to resist shearing weakens as it gets hot and thins out; a phenomenon plotted as a function of viscosity and shear stability known as the Stribeck curve, it is essential that the oil maintain it's specified viscosity at the appropriate operating temperature. This is why Nissan has engineered a fail-safe which limits power until the oil cools back to its specified operating temperature, because at that temperature it should be at the proper viscosity to withstand the high loads of the VVEL system.
Nissan has already recommended a conventional oil with an ester additive (most likely a borate ester) for a TSB with the VQ37VHR. This was designed to reduce noise and ensure proper lubrication at a wider range of temperatures. However, even a synthetic will thin out with heat, and running a high-end synthetic does not guarantee that the thinner viscosity will have the film strength to resist the mechanical pressures exerted on it by the valvetrain's various components.
Like most engines which see racing or track endeavors, increasing the oil viscosity and capacity will most likely be the best solution to ensure proper lubrication at higher temps. There's a reason high-end sports cars like the M3 use a 60 weight oil. Tampering with the oil temperature sensor might very well become a track hound's legitimate option to maintain the engine's power potential, and as long as a heavier weight oil is used, they might be just fine in doing so. Time will tell.
Will (still wishes the 350hp VQ38HR was used in the new Z34 chassis, instead of the VQ37VHR)
