Overheating & What You Can Do To Stop It

[RepyT]

I don’t know if it’s legal but why not just remove hood for track time?

All this aero talk sparks my interest (and some job experience) but with zero data we’re all being the cooling equivalent of ‘butt dyno’ers’!

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[Lust]

I don’t know if it’s legal but why not just remove hood for track time?

All this aero talk sparks my interest (and some job experience) but with zero data we’re all being the cooling equivalent of ‘butt dyno’ers’!

I remember seeing somewhere that the hood being removed at the track didn't solve the overheating problem.

 

[boosted180sx]

the example with the cowl hoods makes sense. im far from am expert but wouldn't pushing more air into the engine bay (with the grill and fog light etc) force the air out the only opening being the raised rear hood? also, wouldn't raising the change the high pressure zones? so like forcing more air into the low pressure zone (i.e. engine bay) and basically pushing it thru the rear of the hood?

i would kinda liken it to a PC case (not sure if anyone here are pc nerds ) but putting fans only on the front of your case to pull in fresh cool air and basically forces the air to exit the chassis opposite the fan locations

i barely past physics so im a bit simple minded. ?

but your actually not pushing more air into the engine bay with the grill and foglights open as your just creating more area for the air to go all over the place rather than ducting it through the heat exchanger where you want it to be. You need a shroud around your heat exchanger for that very reason. A heat exchanger is a resistance to air flow. Air will ALWAYS take the least path of resistance and thats not through the heat exchanger.

they also removed the plastic shroud that goes on top of the bumper? Your just now allowing even more air to escape up and over the heat exchanger ...

your not going to force enough air through the front to push the air out especially when there is air getting sucked in from the rear. how hard do you think the front fans on your pc has to work to push air through the rear case fan if your rear case fan is also an intake. although at t that point, air will never force its way past the rear case fan because the air will take the path of least resistance which would be out the sides of the case or a top fan. (in a car, it could be the bottom of the car or any opening that the air can go to)

 

[Centripetal]

I remember seeing somewhere that the hood being removed at the track didn't solve the overheating problem.

I hope there are videos because going 100+ mph with no hood has to be interesting stability wise and/or amusing

 

[RepyT]

I hope there are videos because going 100+ mph with no hood has to be interesting stability wise and/or amusing

Not obvious but I was just kidding about removing the hood.

Without it, may as well film, “When Air Currents Attack” (or “Air Gone Wild” but some might think Spring Break naughty going topless (hood).

FYI - Shrouds work b/c resistance to pass through objects is less than that required to double back and go around.

Think of this quandary as wanting to specifically control, channel, and maximize airflow volume with minimal drag points added (they have nothing to do with cross-dressing or sports scores) through heat transducers. Just creating holes outside that goal might cool something (non-vital) but you’re Swiss cheese and that takes more power pushing against the air to maintain a speed, more to accelerate. All this gets calculated in CAD before anything is fabricated long before we saw it.

B/L - Doing something to change airflow makes the performer feel better. Changing airflow to perform better takes science Honda used that we don’t have access to. Increased component efficiency can exchange thermal energy better than stock.
Not that anyone is interested in my novice auto (but not aero) opinion but prolly best to improve upon parts (I.e.- use C&R radiator) than try to outthink Honda Engineers (they built aircraft too y’know .Not rope pull start either).
????

 

[Z06Chris]

Dang, this thread sounds like the overheating threads on corvetteforum for the C7 Z06. GM kinda fixed the issue of the LT4 with 10 radiators in the ZL1 and like 14 on the ZR1 ?

 

[MadMage]

ill have to double check the hood later, i thought the metal duct under the scoop kept the air separate form the engine bay air but i could be wrong. I'm been wrong before.

I haven't looked, but the scoop airflow path was mentioned in a video I saw. Don't remember who/what, but is was the only one I didn't call BS on the aerodynamics mentioned. Though not sure it was right either. But, they were pointing to were the scoop air goes and that they felt it was existing on the side near the wheels.

wouldn't pushing more air into the engine bay (with the grill and fog light etc) force the air out the only opening being the raised rear hood? also, wouldn't raising the change the high pressure zones? so like forcing more air into the low pressure zone (i.e. engine bay) and basically pushing it thru the rear of the hood?

As others said, the air would rather go around the vehicle rather than through it. It's one reason the front end of cars are relatively blunt, the engine needs air to go through it. I studied aerodynamics in college (decades ago) and wouldn't hazard a guess without really diving into the fluid & thermal dynamics.

It's a really complicated issue. Not only do you have fluid flow, but you also have to account for heat transfer. None of which are linear relationships, so increasing one thing decreases another. I would love to see the CFD models, but I can assure you Honda keep those protected as closely as they can.

 

[Si_chRis]

Has anyone ever looked into using a lower temperature thermostat with their setups?

I also wonder if the K20C1 OEM waterpump itself is not efficient enough from the factory considering all the extra internal cooling channels this engine has compared to older Honda engine designs.

 

[Centripetal]

Not obvious but I was just kidding about removing the hood.

Maybe it's not obvious but my reply was facetious.

Think of this quandary as wanting to specifically control, channel, and maximize airflow volume with minimal drag points added (they have nothing to do with cross-dressing or sports scores) through heat transducers. Just creating holes outside that goal might cool something (non-vital) but you’re Swiss cheese and that takes more power pushing against the air to maintain a speed, more to accelerate. All this gets calculated in CAD before anything is fabricated long before we saw it.

I'm well aware of Finite Element Analysis and its failures, which is why I mentioned yarn and tape ealier. I would have suggested a wind-tunnel like Honda probably used to develop their jet but I thought that might be out of reach.

 

[Lust]

Has anyone ever looked into using a lower temperature thermostat with their setups?

I also wonder if the K20C1 OEM waterpump itself is not efficient enough from the factory considering all the extra internal cooling channels this engine has compared to older Honda engine designs.

A few people have tried the Spoon and Js thermostat. At full operating temp, the stock thermostat is already fully open. Unfortunately it doesn’t help.

Someone else mentioned the stock water pump not being able to keep up. I don’t have a way of testing this

 

[boosted180sx]

Has anyone ever looked into using a lower temperature thermostat with their setups?

I also wonder if the K20C1 OEM waterpump itself is not efficient enough from the factory considering all the extra internal cooling channels this engine has compared to older Honda engine designs.

if the cooling system is already overloaded, a thermostat should not make any difference. The factory thermostat is fully open at 194 deg F iirc so at the race track doing multiple laps, whether you have a low temp thermo or not, it would be fully open. A low temp thermo will open sooner but the coolant will ultimately rise to the same point if your cooling system is not sufficient enough. It might help just a bit to cool down the car faster during a cool down lap maybe but its not going to help keep the temperatures in check when your doing multiple hot laps.

the thermostats regulates the minimum temperature and not the maximum temperature. The maximum temperature is regulated by the heat exchangers efficiency. If its not efficient enough, it wont make a difference.

The car will only cool as much as the cooling system your running will allow it to. If you want to lower coolant temps, the only things you can really do is to increase the efficiency of your cooling system i.e. increase the number of heat exchangers, increase the surface area/fin density of the heat exchanger, or allow more air to flow through the heat exchanger via shrouds, etc. Also oil temps and coolant temps correlate with each other so lowering one should lower the other.

as for the water pump ... i have no idea ...

 

[lestat2369]

were turbo blankets discussed?

 

[Lust]

were turbo blankets discussed?

I am running a turbo blanket. I did notice a small decrease in underhood temps especially near the inlet.

 

[elmoTK]

I remember seeing somewhere that the hood being removed at the track didn't solve the overheating problem.

Correct. It was on the FK8 Track cars FB page. One of the members in South America. But his temps were extreme. Something like 100°F and 90% humidity? Swampy!

 

[Centripetal]

With more air coming into contact with the radiator you'll want to extract that heat as quickly as possible. The stock hood and even some vented hoods are not great at extracting heat and the air inside the engine bay becomes lazy. Poor airflow behind the radiator increase engine bay temps all across the board. You'l see higher IATs, ECTs, OilTs, etc. This is where a properly vented hood comes into play. My recommendation would be to have a vent right above the turbo. This will help the air escape the hottest parts, the radiator and turbo, as quickly as possible. Varis, Js, and Trackspec all have good options for this.

I thought I'd share some thermal imaging to graphically explain why this is sound advise. The heat from the turbo needs to be dealt with; in some way.

The following is a thermal image of a coated PRL Titanium Inlet Pipe after a spirited drive. The hour glass shape is from the turbo dumping so much heat.

Honda even knew the area needed to be cooled. This hole in the hood is directly over the electronic wastegate actuator and it's likely the purpose is to cool the wastegate electronics.