sdickinson64

Hey all,

I know many of you will say to use the search, but I have been searching for quite some time to try to find some answers that may apply, and some do and some do not. I am just at a loss at this point and need some ideas here.

I am not happy with the cooling of my car at this point as I can only run a few laps in a row before my car goes into limp mode from overheating when on the track. About 6 min when 95-100 outside, and 8 or so min in 75-80 degree weather and the car is in the 290+ oil and maxes out the water temp putting me in limp mode until it cools back down. Now I do have a good amount of racing experience from my racing career from when I was younger, so I do tend to push the car. The only time I am able to keep the temps reasonable is when driving half throttle and shifting at 4k. With this driving style it tends to run 260 oil 230 water which is totally fine, but I'd much rather it come in after a 15 min session around these numbers driving it to much more of its ability.

Here's a breakdown of everything I have done
- Tuned by Nic D on Flex fuel with headers and K&N intake is all I have for power mods. 423whp/428wtq
- 3 core aluminum radiator
- 19 row Derale oil cooler mounted at backside of front grill opening
- -10an oil cooler lines
- 180 degree oil thermostat
- 160 degree water thermostat
- Distilled water/Water wetter for coolant
- Improved racing oil pan baffle kit
- Completely sealed up radiator shroud
- Cleaned radiator, Oil cooler, and condenser
- 4" front splitter with air dam - hole cut for airflow ducted into radiator opening on the bottom of the front bumper and 90% sealed
- 5th gen camaro hood vent allowing heat out the top.
- Amsoil 0w-40 to help with higher temps
- 275 front/285 rear RE-71R tires. Intend to replace with 305 square pirelli Scrubs as I already have the 18x10.5 wheels for the car

At this point, I am not sure what would be the best route. Rerouting my brake ducts allowing me to mount 2 19 row oil coolers behind fog light openings and running them both together or a larger center mount oil cooler that goes across entire front bumper opening. Also would either of these completely fix this issue and allow me to push the car for a 15-20 minute session without having to worry about cooling the car down during the session? I do not tend to run often in 100+ heat here in AZ, I tend to only do fall/winter/spring events below 90 degrees. That and I am also worried about when I put the slicks on and am able to be on throttle sooner and longer creating even more heat.

If anyone has any suggestions, I am looking for ideas here. Highly considering making some new condensor lines so I can lay the rad/condensor down and vent out the hood, but is this going to help much with the oil temp? I am under the assumption that the high oil temps is bleeding the heat into the coolant heat, so I am not sure about all that work if I can get the oil temps down enough to alleviate the entire problem.

Thanks guys.

Dane@LGmotorsports

Any pics of your oil cooler mounting?

ajderzie

So you have an aftermarket radiator and oil cooler. My guess is thats probably not the problem. It could be that your thermostat is not working allowing circulation of the coolant or your mixture of water and coolant is possible the issue. Assuming there is no obstruction to airflow into radiator, I would change/flush the coolant (I'm sure its fine but who knows) and then focus on the thermostat. If you get caught out with engine overheating, put on your heater full blast (yes, even if it's 100 degrees out). It will remove a lot of heat from engine bay.

TrackAire

Just to verify, is your car a manual transmission or automatic?

Something is not right....I would definitely look at the tune. Sounds like something might be off there, possibly running too lean, timing curves off, etc. For it to go into limp mode that quickly, I would also suspect and change out both the oil and coolant thermostats just to be safe.

Good luck and hope you get it figured out quickly.

Supercharged111

The thing that caught my eye was a 3 row aluminum radiator. That sounds suspect. The only ones I've seen are ching chong units. Aluminum cores should be 1" wide each to be effective and I doubt you have a 3" thick radiator.

Bill Dearborn

I agree there is probably something going on with the radiator. You should have more than enough cooling capacity to run a complete session in 75-80 degree weather. A lot of people run fine once an oil cooler is added. The DeWitts and Ron Davis Racing Radiators which are best in the business providers both have two one inch wide rows.

However, you mention how you have ducted air to the radiator. I believe the base C6 includes some bottom breathing air flow into the radiator. Do you have a center air dam deflecting air upward into the radiator? Make sure you are getting air to the complete radiator. If you have modified the car so it take in all of it's cooling air from the front make sure the bottom is closed off or air will bypass the radiator.

Bill

chetly

Might also look into putting some more holes in your hood. The 5th gen Camaro vent isn't really that big compared to some of the vented hoods or aftermarket louver kits out there.

Go watch that video posted in the other subject about group buy for race louvers. You'll see what I'm talking about.

Glowing Rotors

Here are some things I learned about my C6Z cooling over the years, .....

I took out the thermostat, plugged the bypass and plugged the cabin heater lines.. This bypass opening is at the bottom of the thermostat housing in the water pump and it allows more water to go to the heater core in the cabin when the engine is warming up and the thermostat is closed. A 1.125 inch freeze plug worked for me. Tap a freeze plug into the bypass hole with a deep socket. The engine takes a little longer to heat up, but you know that all the water is going to the radiator all the time. You can always put in an orifice in place of the thermostat to slow down the flow, but I have not seen the need to do that.

Air flow to the radiator needs to be as unrestricted as possible. I have nothing in front of the radiator. And my shroud fits pretty tight to the radiator. All coolers are behind the radiator or get cooling air from the fog light openings. Years ago I had a small setrab power steering cooler on the driver side of the main opening and after 4 laps on a 95 degree day, I overheated the engine (LS7) to the point that it needed a major rebuild. Since then I put that PS cooler on the driver side fog light opening, which lets more air flow through the radiator.

I moved the transmission cooling to a small, fan powered cooler in the rear of the car. This reduced the heat load up front.

I removed the A/C long ago, but on a hot day I wish I still had it....

sdickinson64

Hey all,

Thanks for the input. Just wanted to answer a few of the questions I got here and include some images as requested.

- The car is a 6 Speed Manual
- I have the front opening for the radiator with the oil cooler mounted in front of the radiator as I thought it was supposed to be.
- The bottom feed is now cut into my splitter air dam with deflectors on each side directing it back to the center opening, with a plate resting flush on the splitter to duct the air up into the radiator opening and bypassing the oil cooler as it comes in directly below it.
- This problem was occurring with the factory radiator and as it only gets hot when the oil temps start to get up in the 250+ range, I did not feel like I needed to increase the water cooling capability all that much and did get the ebay one since its significantly bigger than the factory one and allows more water to be in the system. I was operating under the diagnosis that I need to address my oil cooling more so in order to keep those temps in check and that will keep the water temps cool enough to run longer, but I am getting from the responses that that may not be accurate?
- I was going to leave the hood with just the single center vent until the point at which I need to tilt the radiator forward and duct directly out the hood, then of course I will need more opening to increase air flow and decrease temps. Is that a valid idea there?

I guess my main question here is if I do something to bring down the oil temps significantly so it only gets to 260-270 after a 15min session, would that fix my water cooling problems? And what would be the best easiest way to accomplish this? 2 19 row coolers behind the fogs (would this decrease oil temps enough or would it just make a small difference and still need more cooling), one large oil cooler across the entire front opening (blocking some air flow through the radiator), or some other method?

Here is pictures of my oil cooler mounting location with the shroud off (off course I put in on and taped it up as necessary to seal the minor cuts that had to be made to fit the cooler), My extra front splitter opening to duct more air in from the bottom, as well as my Dyno Graph from a few weeks back. Definitely hope its not my tune.

Glowing Rotors

Here are my suggestions about your system based on my limited experience.....

1) Move the oil cooler. See how your temps change without the oil cooler in front of your A/C & Radiator. Inlet air takes the path of least resistance and that cooler out front may be diverting or slowing down too much air that the radiator needs....

2) Take out the thermostat and plug the bypass and heater lines. Cheap and easy to do.... (Dorman Expansion Plug P/N 555-019 1.125 inch diameter)

Another thing I did years ago was to get an aftermarket fan controller to force the radiator fan to high speed all the time. This may not be a big issue for you at the temps you are running as the
OEM controller should be directing the fan to high speed anyway.

Supercharged111

It looks to me that your bottom intake is a bit smaller than the factory inlet, correct me if I'm wrong here. That 3 core is going to be inefficient. Aluminum doesn't transfer heat as well as brass/copper which is why they use 1" tubes for aluminum and 5/8" tubes for the brass. At 1", the aluminum tube will work better and it can be done because aluminum is stronger. I'd go back to stock first and get an idea of whether that 3 core is better or worse than stock.

TrackAire

Not sure about the brand or model of your radiator, but if the core is too thick, then the air flow can't push through it efficiently to transfer the heat. Air in front of it then stagnates. Fans do nothing (running or not) at race speeds...they actually limit the air flow through the radiator. I think anything over 40 mph, the fans are a detriment to helping cool the car on the track.

Having said that, I think the issue may be how you have the air intake openings set up on your car.....I'm wondering if the front opening is stagnating the bottom feeder or vice a versa. It may be worth it to tape on a bunch or yarns on the front opening edges and Go Pro video what the strings are doing at 70 plus mph. You might actually have the strings pushing outward instead of inwards towards the radiator.

For ***** and giggles, you may want to tape up the front opening completely with painters tape and drive at highway speeds to see what the temps do. If it gets worse, block off the bottom feeder and see if the front intake is better.

Also, is there something blocking the sides of the radiator to keep air from going around the condenser and radiator stack? If too much air gets behind the radiator it will pressurize the engine compartment and let less air through radiator stack.

sccaGT1racer

You need proper ducting. Air will go to the easiest path.

Mordeth

I've dealt with this for years on multiple C6s including my own C6Z race car. Airflow is paramount. You must direct all incoming air through the grill to the radiator, everything must be sealed and then the air leaving the radiator needs a natural place to go, preferably to a low pressure zone. You need to start moving things out from the front of the radiator. The oil cooler is not only slowing down the air entering the radiator, but it is superheating it. If you have a hole cut in the bottom of the splitter/undertray behind the radiator for air to exit, then you need to install a small flap in front of that hole to make that hole a low pressure zone which will help to draw air out.

So again, air needs an unimpeded path that is directed (via sealing on all sides and top) to the radiator and then a place for it to go. Also, is your hood vented?

sdickinson64

I had not considered the idea of the flap at the end of the splitter. It is open behind the radiator as stock, but I guess with the splitter I have increased the pressure going under the car and did not think about it drawing the hot air back out. I can take care of that rather easily.

I am also considering doing a dual rear mount oil cooler setup instead of trying to tear my front end apart to make it all work. Rather make both systems as cool as possible then try to cram everything in there up front. I would take off the condenser if I didn't drive it on the road occasionally, but as of now, I do enjoy going for little road trips and canyon cruises in it and need it half the year here in AZ.

Thank you for the help, and I had a follow up question, it seems like everyone on here is pointing towards the radiator being the issue. I was thinking its the oil heat causing the problem since I don't see any problems with the water temp until my oil temp gets up over the 250 mark (doesn't even hit 200 until the oil is up around 220-230) Water gets really hot and will go into limp mode when the oil is sustained up in the 280-290 range. Completely agree with allowing the radiator to cool as much and efficiently as possible, but still think the root of the issue is the oil cooling, not the water cooling.

Dane@LGmotorsports

Air is just going around your oil cooler, it needs ducting. You'd see a small temp drop just from putting a few inches of aluminum jutting forward from the edges to trap air rather than it just slipping around. Think of the air as water, you'll catch a lot more with a box structure than you will with a plate.

Also what Mordeth is saying is correct, I'm just talking about your oil cooler itself and why it isn't working in current form.

SkittlesRgood

Yes, your engine is heat soaking and coolant and oil are all heat soaked too. Cooling one will help cool the other. My base c6 auto radiator is like 80% covered by oil coolers. Putting them somewhere else is definitely better but I don't think that's your problem. I went with a much bigger oil cooler than you so that might help. But if you don't have the radiator shroud on, like in your picture then that is 100% your problem. Absolutely no doubt in my mind. My coolant temp got high enough to go into limp mode one day and I noticed a 2" gap in my shroud where it meets the bumper/crash bar. Used some aluminum tape to pull the shroud to the bar and that made a ~15* difference. get that shroud back on!

sdickinson64

Lol, yes I do run the shroud. I just had it off when I took the picture to better show the layout while I was adding my oil thermostat in there.

At this point, I have a larger high flow oil cooler coming that I will be mounting in the rear end of the car with 2 fans mounted behind it to try to alleviate some of the issue. If that's still not enough, I have room to do one on each side worst case scenario. Will update with results once I get it all installed and tested.

SkittlesRgood

lol I thought so but you didn't correct the people suggesting it before so I had to make sure.

It's weird man. My car got hotter than most just on the highway and got up above 290* on track. So I added EOC and TOC and that alone fixed it. With the hood vents and everything you have... Doesn't make sense.
But this thread did make me realize what the stock spoiler/air dam thing is for. Low pressure to suck out air behind the radiator. Since I took mine out and made an underbody tray... might be a good idea for a hood vent now. Except I park outside

ajderzie

By the way, is the fan coming on?

Check out these links as a possibility