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Did a TNIA at pocono raceway. I lasted 15 minutes at pretty much full stop before I hit limp mode. Coolant was 260, oil was 240. Car is 150000 miles, boosted. I have future plans for track days and would like to see what I can do to limit overheating. First step is flush the old coolant and oil. I'd like to install an oil cooler radiator but I'm not sure what lines to tap into or where. Next step as I was suggested by other LS guys was some air ducting to the radiator. If anyone cares to shed some light on this I'd greatly appreciate it.
 

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To the top for an answer(s) to this man's problem.
 

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The stock oil pan has a block-off plate for the oil cooler lines that would have been installed for such heavy duty usage.

I also took the liberty of finding a low profile cooler manifold for that location. It says it would fit the G8.


Edit: I had to go back and edit because I realized I overlooked an important question.

Are you on DOD? Or did you do a DOD Delete while blocking off the relief valve port in the oil pan? It is important, as higher viscosity oil may just end up discharging through the relief valve, which may cause problems with higher viscosity at operating temperature.

It's more of a disclaimer for me, because while the oil will be thinner at operating temps, pressure will want to increase. Having a plug in there will allow for the increase without sacrificing flow.

If you are DOD Deleted and plugged the relief port, then you should consider something other than 5W30 Oil. Try stepping up your oil viscosity to a 5W40, or even 5W50 for racing applications.

It will handle shearing forces better than 5W30, and you won't have any problems at startup getting oil where it needs to go as the viscosity will remain the same as any other oil rated SAE 5 at startup temperature.

That alone should kick your oil temps down some. The oil film thins out at high RPMs due to the aforementioned shearing forces, and the SAE 40 or 50 rating at operating temp will help alleviate some of that. (BITOG has good reading on this subject).

Installing a cooler may hurt your ability to get up to temp during normal driving, though.

I'm not sure what to tell you about your coolant loop. Assuming everything is in order, your Radiator needs to be able to handle more heat. I wonder, though, if something is wrong. That, I cannot say....
 

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Discussion Starter #4
thanks jova!
 

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Did a TNIA at pocono raceway. I lasted 15 minutes at pretty much full stop before I hit limp mode. Coolant was 260, oil was 240. Car is 150000 miles, boosted. I have future plans for track days and would like to see what I can do to limit overheating. First step is flush the old coolant and oil. I'd like to install an oil cooler radiator but I'm not sure what lines to tap into or where. Next step as I was suggested by other LS guys was some air ducting to the radiator. If anyone cares to shed some light on this I'd greatly appreciate it.

An oil cooler is a great option but your coolant temps might be the main issue. First I'd make sure your thermostat is working fine and check your tune to ensure your fans are coming on quick enough. If you are going to be running at the track with a forced induction car you are going to want those babies running full throttle all day.

The next question is what type of boost are you running? The problems could be stemming from your intake temps.
 

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Discussion Starter #7
what kind of boost? 6 psi. This was my 4th track day this year. First time overheating.
 

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Check your belts, if they're worn, you won't get traction on the water pump pulley... that can cause overheating

Replace Tstat with 160 or just remove it (will need re-tune)

Replace the radiator with all aluminum as the stock plastic one is prone to failure (like mine did)

Perhaps make the hood scoops functional if it's a track only dry car... more airflow over the motor can help cool it down.
 

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Discussion Starter #9
done all that haxagod, minus an aluminum radiator.
 

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Not to complicate things further, but just because I had it happen to me during a track day I thought I'd mention that the 6L80 will generate a fair bit of heat during hot laps. I watched my coolant temps throughout my first few laps and never saw much over 220 and didn't bother thinking about the trans until 30 minutes in and the car goes in limp mode. Granted I've got an aftermarket converter, but also a decent size auxiliary cooler too.

After coasting back to the pits I checked the engineering mode to see a sump temp of 158 degrees......celsius. So yeah, if you haven't make sure to keep an eye on that if you haven't already.
 

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Discussion Starter #11
I'd never checked the trans temp.
 
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