Track Time Limited due to High CHT

[67Fast_V]

I agree, the grille is a big ticket item. Great to know that top grill only gave 12-15F. Thanks for sharing. I have the upper and lower modified now but not installed. So maybe my calc's are conservative. Hard to estimate the increasing heat load when the cooling temps drop. That's my struggle. I hope I see your improvement level ... vs. mine.

Unfortunately when you increase the grille opening there is an Aero penalty. So I didn't want to take that hit unless I couldn't get there any other way. I will get one more data point (98% sealed) and then decide where to go w/ the grille. Can do the upper or lower only ... or both.

However based on my measurements, calculations, cruise data, and track data, the best knob in the system in my opinion is to seal the radiator. You get a huge cooling improvement and it helps the Aero too. So win-win. And its pretty easy to get 75% of it. About 4-6 hrs of work and $15. The last 25% in the front is not so easy ... but very do-able.

So for those that are experiencing cooling issues or just want lower temps for engine robustness, power, etc, I would highly recommend you spend the 1 day and go after the side and bottom sealing of the radiator. If someone wants some tips, can ask here or send me a PM. Glad to help where I can.

If you want to get a sense of how bad the factory sealing is, just take 5 mins and remove the 8 little push pins on the radiator top cover plate and look around ... you will see monster "holes" on the sides that are bleeding off the radiator airflow. Shocking size openings, really, with no attempt by the OEM to seal.

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[67Fast_V]

If you are asking me, Alex, my daily temps are ice cold. 180-185F CHT around town. I have 170F t-stat and runs 10-15 above the initial opening temp.

Never had an issue w/ daily driving ... even w/ no sealing and sporty driving. On the track w/ 3rd - 7th gear WOT, totally different story ... as you well know more than me.

 

[Flyhalf]

CHT are really under control for me.
I believe the Mishi bigger rafiator did really good.
Also engine oil is related to CHT
i really think is time to separate the 2.system.with a cooler.
I'm ok with the small mishi oil.cooler but mainly cause I do.time trials. Less.oil temps better CHT.
Question. What fluids are u using?(for radiator and oil)
And
To share
Attached the possible combo ideas i have.

 

[tosha]

I agree, the grille is a big ticket item. Great to know that top grill only gave 12-15F. Thanks for sharing. I have the upper and lower modified now but not installed. So maybe my calc's are conservative. Hard to estimate the increasing heat load when the cooling temps drop. That's my struggle. I hope I see your improvement level ... vs. mine.

Unfortunately when you increase the grille opening there is an Aero penalty. So I didn't want to take that hit unless I couldn't get there any other way. I will get one more data point (98% sealed) and then decide where to go w/ the grille. Can do the upper or lower only ... or both.

However based on my measurements, calculations, cruise data, and track data, the best knob in the system in my opinion is to seal the radiator. You get a huge cooling improvement and it helps the Aero too. So win-win. And its pretty easy to get 75% of it. About 4-6 hrs of work and $15. The last 25% in the front is not so easy ... but very do-able.

So for those that are experiencing cooling issues or just want lower temps for engine robustness, power, etc, I would highly recommend you spend the 1 day and go after the side and bottom sealing of the radiator. If someone wants some tips, can ask here or send me a PM. Glad to help where I can.

If you want to get a sense of how bad the factory sealing is, just take 5 mins and remove the 8 little push pins on the radiator top cover plate and look around ... you will see monster "holes" on the sides that are bleeding off the radiator airflow. Shocking size openings, really, with no attempt by the OEM to seal.

I would very much appreciate a how-to guide or some tips on building up the sides+bottom ducting

 

[67Fast_V]

CHT are really under control for me.
I believe the Mishi bigger rafiator did really good.
Also engine oil is related to CHT
i really think is time to separate the 2.system.with a cooler.
I'm ok with the small mishi oil.cooler but mainly cause I do.time trials. Less.oil temps better CHT.
Question. What fluids are u using?(for radiator and oil)
And
To share
Attached the possible combo ideas i have.

Good options. Thanks. I think the extent of the mods necessary depends on the usage type (Racing, Time trials, short HPDE, long HPDe), how hard you push, transmission type, and type of track. Grossly different heat loads depending on all those factors. I run short HPDEs, on low speed/gear tracks, and push a decent amount and of course w/ the A10.

Glad to hear your CHT levels are good now . Those spray misters are pretty cool.

As far as fluid types, I run 22% antifreeze and water wetter. And use 5w-40 or 5w-50 Mobil 1 syn., depending on what is available. With the oil temps I'm running (edge of yellow/green ~ 285F), likely 5w-50 is better. But I expect oil temp to come down to 275F-280F for the next event.

I'm reluctant to change the oil cooling on the GT unless I really need to. Cooling oil w/ air is tough duty. Takes a lot of surface area. Utilizing water is much more effective but gotta keep water temps low enough for it to work.

If the heat load is high enough and for extended period like what you and Bob and others are doing, then I can see where there is not much choice but to separate the oil from the cooling system. I'm not there yet. I will have a better gage in June. Going to be hot in FL.

 

[67Fast_V]

I would very much appreciate a how-to guide or some tips on building up the sides+bottom ducting

I didn't install or fab my own ducting, that's a much bigger job that I didn't want to bite off at this time. In general, what I did is seal up the OEM panels and holes/opening with a combination of black duct tape and custom panels.

Tips:
A. remove the underbelly pan/tray and start on the bottom. The bottom radiator panel needs to be sealed in the front and rear. You will see it's open on both ends. I used 3M "extreme hold" black duct tape to seal it. It's much thicker than the std duct tape and has better adhesive. It's $10-12/roll vs cheap stuff is $6-7.
- Clean all taped surfaces w/ rubbing alcohol first and I tape over the areas in different directions w/ 2 overlapping layers total as a minimum.
- In all 4 bottom corners, you will see massive holes/openings. I took std corrugated cardboard and cut out a custom shape panel to fill the opening. Once I was happy w/ the shape, I covered it entirely w/ the black duct tape to seal it from the elements. Surprisingly it makes it pretty stout panel for what it is. The 3M extreme tape is thick. You will see if you try it.
- And with the custom panel, I would look to wedge it in place against something more structural (behind a bolt, bracket, etc) and then use the black duct tape to hold it in place and seal the perimeter.
- For the sides of the radiator, I would make custom panels and lay those on top or adjacent to the OEM plastic seal strips. Leak areas all over the place. Used the black duct tape to hold and seal where necessary.
- I probably made 15-20 custom panels. Some no bigger than 1' x 2", Some 4" x 6". Some 1.5" x 9". All sorts of crazy shapes with bends and angles ... all to fill the irregular openings. Easy to cut cardboard and tape. Doing this with aluminum would be 5x more difficult. Plastic sheet ... maybe 2-3x. All do-able, just time.
- I left some small water drainage holes in the bottom rear panel (aft region,1 on each end and 1 in the middle)
- After the bottom is done, then you can work on the top. Remove the OEM plastic upper radiator panel via the 8 small push pins. Then look to the left and right. Huge opening that you want to make custom panels for. Same approach. Also go after the upper sides of the radiator. You will see all those openings.
- 6 hr job. Maybe 8 hrs. I did all the above in 1 day. Good for 70-75% of the leaks.
- Note that there are a lot of smaller leaks that you will see. Up to you if you want to chase them out. It's just time. For the first round, I did not bother. But for my final round recently, I did.
- So far, I have been through 3 track days with the above. 140 mph many times. Some of the tape ~5% came loose and allowed air to leak by. 1 of the custom panels moved on me and wasn't sealed anymore. Driven in the rain once, and it was fine. But jury is still out on the impacts of water.
- Overall, I'm pretty happy with it. Not the most robust solution but easy to implement and fail safe. Taped cardboard isn't going to cause any issues. But I will say that removing duct tape adhesive is no fun ... so if you have to remove any of this to replace parts, etc, that will be a crappy job. I've had to do a little of that already.

B. To get the remaining 25-30% leakage, the front nose/bumper needs to come off. More involved and another discussion needed. Took me 2 days start to finish, including the nose removal/install (1st time for me and I was slow). A lot of very tricky leaks ... like running down through the frame and out the ends. Also made a custom panel to seal under the OEM upper plastic radiator cover since that doesn't seal well. It's ~4" x 20". Have not track tested the front leak sealing yet. June.

Hope this is helpful to you. Cheers.

 

[tosha]

I didn't install or fab my own ducting, that's a much bigger job that I didn't want to bite off at this time. In general, what I did is seal up the OEM panels and holes/opening with a combination of black duct tape and custom panels.

Tips:
A. remove the underbelly pan/tray and start on the bottom. The bottom radiator panel needs to be sealed in the front and rear. You will see it's open on both ends. I used 3M "extreme hold" black duct tape to seal it. It's much thicker than the std duct tape and has better adhesive. It's $10-12/roll vs cheap stuff is $6-7.
- Clean all taped surfaces w/ rubbing alcohol first and I tape over the areas in different directions w/ 2 overlapping layers total as a minimum.
- In all 4 bottom corners, you will see massive holes/openings. I took std corrugated cardboard and cut out a custom shape panel to fill the opening. Once I was happy w/ the shape, I covered it entirely w/ the black duct tape to seal it from the elements. Surprisingly it makes it pretty stout panel for what it is. The 3M extreme tape is thick. You will see if you try it.
- And with the custom panel, I would look to wedge it in place against something more structural (behind a bolt, bracket, etc) and then use the black duct tape to hold it in place and seal the perimeter.
- For the sides of the radiator, I would make custom panels and lay those on top or adjacent to the OEM plastic seal strips. Leak areas all over the place. Used the black duct tape to hold and seal where necessary.
- I probably made 15-20 custom panels. Some no bigger than 1' x 2", Some 4" x 6". Some 1.5" x 9". All sorts of crazy shapes with bends and angles ... all to fill the irregular openings. Easy to cut cardboard and tape. Doing this with aluminum would be 5x more difficult. Plastic sheet ... maybe 2-3x. All do-able, just time.
- I left some small water drainage holes in the bottom rear panel (aft region,1 on each end and 1 in the middle)
- After the bottom is done, then you can work on the top. Remove the OEM plastic upper radiator panel via the 8 small push pins. Then look to the left and right. Huge opening that you want to make custom panels for. Same approach. Also go after the upper sides of the radiator. You will see all those openings.
- 6 hr job. Maybe 8 hrs. I did all the above in 1 day. Good for 70-75% of the leaks.
- Note that there are a lot of smaller leaks that you will see. Up to you if you want to chase them out. It's just time. For the first round, I did not bother. But for my final round recently, I did.
- So far, I have been through 3 track days with the above. 140 mph many times. Some of the tape ~5% came loose and allowed air to leak by. 1 of the custom panels moved on me and wasn't sealed anymore. Driven in the rain once, and it was fine. But jury is still out on the impacts of water.
- Overall, I'm pretty happy with it. Not the most robust solution but easy to implement and fail safe. Taped cardboard isn't going to cause any issues. But I will say that removing duct tape adhesive is no fun ... so if you have to remove any of this to replace parts, etc, that will be a crappy job. I've had to do a little of that already.

B. To get the remaining 25-30% leakage, the front nose/bumper needs to come off. More involved and another discussion needed. Took me 2 days start to finish, including the nose removal/install (1st time for me and I was slow). A lot of very tricky leaks ... like running down through the frame and out the ends. Also made a custom panel to seal under the OEM upper plastic radiator cover since that doesn't seal well. It's ~4" x 20". Have not track tested the front leak sealing yet. June.

Hope this is helpful to you. Cheers.

That's awesome, thank you! I was thinking of taking off the front facia and fabricate something, but at the same time didn't want to deal with all the metalwork, I will give it a thought about your method.

On a side note, any thoughts about this one: https://shop.watsonracing.com/product-p/wr-15-rrradcloseout.htm ? Putting the price aspect aside, is it a good option? Anyone tried it? Also, what is the purpose of those tube extensions, anyone knows?

 

[67Fast_V]

That's awesome, thank you! I was thinking of taking off the front facia and fabricate something, but at the same time didn't want to deal with all the metalwork, I will give it a thought about your method.

On a side note, any thoughts about this one: https://shop.watsonracing.com/product-p/wr-15-rrradcloseout.htm ? Putting the price aspect aside, is it a good option? Anyone tried it? Also, what is the purpose of those tube extensions, anyone knows?

Sure thing . Glad to help. I looked at the Watson product. Hard to know how it will fit unless you try it (or get feedback from someone that has). And also whether it was designed with the A/C condenser in mind. I would definitely ask them ahead of time if you want to purchase. All the cars I've seen with sheet metal (AL) ducting have the condenser removed which makes it significantly easier and more manageable. But I'm sure it can be done w/ the condenser if enough effort is applied. But either way you go, there will be a lot of custom fitting.

The difficulty in sealing this system is the geometry. It's a complete mess. The bottom corners, top corners, the sides with condenser and trans cooler, ... just totally irregular shapes. Everything needs to be custom. Once you take a look, you will see what I'm talking about. It's so bad it can be frustrating and requires some patience (a lot of). Getting the last 10% was painful for sure.

The good thing though is you can get ~70% sealed w/o removing the nose/bumper cover or dedicated ducting as discussed previously. And in most cases, that might be good enough, although it will not be as elegant as nice aluminum duct work. And in lue of the last 30%, as EFI forum member rightly pointed out, the grille size is a big knob. So that can be used to get additional cooling.

As for me, I went for the 98% solution and likely the bigger grille will be needed as well. The heat load w/ the A10 using 3rd gear and up and shifting at 7000 rpm+ is tremendous. Even using 4th and up is too much for the system w/o all these improvements. Good luck w/ your project..

 

[ZPD]

man, I wish I knew about that Watson Racing kit. I just spent the weekend boxing my radiator in.

 

[Ewheels]

It's been a while since I provided an update on my cooling issues, so here it goes.

Since Nov 2021, I have run 2 additional track events. One w/ the same configuration as outlined above ("sealed" radiator + fan shroud mod) and one w/ added hood louver. Both still ran unacceptable temps. 251F CHT max w/o hood vent and 247F w/ vented hood. So the hood vent gave 4 degs lower temps. I was expecting 5 degs. So not a surprise that the vent didn't fix the issue.

But I believe I found the smoking gun. Based on my calculations, I decided the best course of action for my application/usage was to modify the grille to increase the flow. ISince the radiator flow is metered by the grille, I have to open it up by 50%+ to cool this beast off based on my calcs. It's an Aero hit but gotta reduce temps.

However when I pulled the front nose of the car to install the bigger grille, I noticed massive leaks around the radiator. I thought the system was mostly sealed but it wasn't. You can't see these leaks unless you remove the nose of the car. It's about 45 in^2 of open area which will bypass the radiator. Ridiculous. My calcs show that plugging this leak will drop CHT by 10F. So that will put me at 237F max which is pretty good, given the situation.

So I sealed the leaks and did not install the bigger grille. After I run in June, I will install the bigger grille which should put me around 229F max CHT (assuming the leak reduction gives me the expected benefit).

At this point, this is all on "paper" ... but I'm confident that I've found the solution for my usage. I should be able to get by with the stock PP1 radiator and stock oil cooler. The trans cooling will likely need some medicine. It's borderline to flyhalf's recommendation of 225F max. But after June's run in the FL heat, I will have better idea. Cheers.

Those CHT's still make me think there's something else going on here. CHT should never be nearing 250° (personal opinion: you should back off once it gets to 240° so your engine doesn't blow).

My last track weekend: 90° ambient, max CHT 235° with hood vent, aftermarket grill, no ducting, 0w40 oil, and that's it. No other cooling mods. I was running the full 20 mins for the session too. Granted I was 5-7 seconds off TT3 pace but that still wouldn't account for 15° CHT difference.
If you're hitting 250° CHT, I still think there is air in the system or possibly you have a defective sensor but CHT should not be hitting that high even completely stock.

 

[67Fast_V]

Those CHT's still make me think there's something else going on here. CHT should never be nearing 250° (personal opinion: you should back off once it gets to 240° so your engine doesn't blow).

My last track weekend: 90° ambient, max CHT 235° with hood vent, aftermarket grill, no ducting, 0w40 oil, and that's it. No other cooling mods. I was running the full 20 mins for the session too. Granted I was 5-7 seconds off TT3 pace but that still wouldn't account for 15° CHT difference.
If you're hitting 250° CHT, I still think there is air in the system or possibly you have a defective sensor but CHT should not be hitting that high even completely stock.

I don't like to see those CHT levels either but they occur very quickly and not functionally avoidable unless I go real easy and essentially goof-off. For example, I exit a corner leading on to a long straight, CHT might start at 235F exiting a 55 mph turn. No problem, that's an acceptable temp. Well by the peak of that straight before I'm into the brakes, max speed of 143 mph, CHT will be 242-243F. About +6-8F is what I get down a straight section that takes 8-10 secs. Start in 3rd, shift near redline in each gear (4th, 5th, 6th, and ride 7th until I need the brakes).

I glance at the temp's occasionally during a session, but I don't study them. Too much else to do as you well know. Good thing is that I have the data logged on a laptop secured in the car. Data every fraction of a second. So after each session I take a look at things (all temps and many other parameters). I will have to get a graph put together to show what happens during a 15-20 min session. The temp totally depends on when you look at it.

What has worked best for me is traffic. I don't mind it at this juncture cus it forces me to slow down and temps drop like a rock when that occurs (like from 240F to 225F in 1 lap). By the time I do the cool down lap (in lap), temps are 215-220F. In the pits at 210F.

As far as the causes of these higher temps, I have thought about the CHT sensor being erroneous and replacing it. So I agree w/ you that is a possibility. But it behaves perfectly. Totally consistent. There is no indication of an issue, on the track or street. Other than high readings at the track when I'm on it. And replacing the sensor looks tough. My thought was to add a secondary gauge and run that into the car and compare to what the ECU reports as coolant temp(ECT). It's on my list ... but have been too busy with my tape .

Note that CHT at 245F puts ECT at 232F which is not too high. But I am assuming that Ford knows how to calc the coolant temp correctly.

But I'm glad your temps are low/reasonable. Sounds like you have a good set-up. Note that aftermarket grille will likely drop your temps by 10F or more on an incremental basis. If you want to measure or estimate the area of your aftermarket upper and lower grille, then I can run a calc to let you know what that is doing for you.

Thanks for thinking on this and for the feedback. Cheers.

Side note: Redline (fuel/ignition cut-off) is 6800-6900 rpm in 6th gear for me. This appears to be the factory setting for 18' & up GTs. Anyone found anything different?

 

[tosha]

Those CHT's still make me think there's something else going on here. CHT should never be nearing 250° (personal opinion: you should back off once it gets to 240° so your engine doesn't blow).

My last track weekend: 90° ambient, max CHT 235° with hood vent, aftermarket grill, no ducting, 0w40 oil, and that's it. No other cooling mods. I was running the full 20 mins for the session too. Granted I was 5-7 seconds off TT3 pace but that still wouldn't account for 15° CHT difference.
If you're hitting 250° CHT, I still think there is air in the system or possibly you have a defective sensor but CHT should not be hitting that high even completely stock.

You have a manual transmission, that isn't trying to boil the whole system all the time

 

[tosha]

(Keeping this great discussion going)

What are everyone's thoughts between going just with racelouvers rx center vent, or rx center + rt side hood vents? Are sides really worth it or center vent would do most of the work anyways?

 

[67Fast_V]

(Keeping this great discussion going)

What are everyone's thoughts between going just with racelouvers rx center vent, or rx center + rt side hood vents? Are sides really worth it or center vent would do most of the work anyways?

In general, the more open area in the hood the better, especially with an unsealed radiator since the engine bay flow is higher. But there comes a point of diminishing returns. I'm not sure how much more open area you get w/ the side vents. Just calc. it based on estimated physical throat area and see if it can justify itself. Or better yet, call Race Louvers. They are great at helping and providing product support. One of the best ones to deal with, in my experience.

As far as cooling is concerns, it's not a significant knob as discussed previously ... as compared to sealing and grille size. But there is an Aero benefit, although not big either. The biggest benefit I saw for the vent is now my hood doesn't shake at high speeds. This was a little unnerving the 1st time going 140+. The vent fixed it.

I installed only a center vent and even though race louver has a more effective design, I was looking for a more low profile look and decided on trackspec. It works, just not as well. I went cheap and only got the center. Might need the sides if I go with the big grille.

FYI ... I measured the pressure in the engine bay before and after the vent. 80 mph cruise. 0.3 in H20 dP above ambient. After vent install, went down to 0.1 in H20. Now w/ all my sealing, it's pretty much the same as ambient pressure (0 inH2O).

 

[tosha]

In general, the more open area in the hood the better, especially with an unsealed radiator since the engine bay flow is higher. But there comes a point of diminishing returns. I'm not sure how much more open area you get w/ the side vents. Just calc. it based on estimated physical throat area and see if it can justify itself. Or better yet, call Race Louvers. They are great at helping and providing product support. One of the best ones to deal with, in my experience.

As far as cooling is concerns, it's not a significant knob as discussed previously ... as compared to sealing and grille size. But there is an Aero benefit, although not big either. The biggest benefit I saw for the vent is now my hood doesn't shake at high speeds. This was a little unnerving the 1st time going 140+. The vent fixed it.

I installed only a center vent and even though race louver has a more effective design, I was looking for a more low profile look and decided on trackspec. It works, just not as well. I went cheap and only got the center. Might need the sides if I go with the big grille.

FYI ... I measured the pressure in the engine bay before and after the vent. 80 mph cruise. 0.3 in H20 dP above ambient. After vent install, went down to 0.1 in H20. Now w/ all my sealing, it's pretty much the same as ambient pressure (0 inH2O).

Thanks, I look at it more as multiple approaches complimenting each other, rather then making choices. I don't want to mess with ducting and opening up the grilles before I add a way to extract all the additional air that will be coming in (hood buffering and lift), so adding louvers seems to be a good first step. I will have an opportunity to test it first and then add ducting and test again. Would be interesting to see progression. As long as I can cut up to 10 degrees just with louvers, that would be great.

My goals for the reference - I have manual GT with PP1, so no issues with transmission oil heating up everything else. However, I also have a roush/fp supercharger, which is adding quite a lot of heat. I don't have issues short shifting, as I'm not chasing any lap records and have enough torque at any point in rev range. I also live up north, so I don't have to deal with very high ambients. In my recent HPDE event, the first day it was 50F and raining almost all day, next day it went up to 65F with sun. Car did great, especially on first day I don't think I saw CHT's going over 210F. On a second day, it started climbing towards 225F, but 1-2 cooldown laps per session kept it in check. As long as I can stay within 230F range during warmer days, I would be happy with the result.

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