FL5 Overheated on Track

[Gansan]

I'm personally not convinced the intake pipe routing is all to blame. The compression of the air in the turbo is responsible for much more heating than heat going into the intake pipe. PV=nRT and all that. The heat shield of the turbo is shielding the majority of radiant heat from it anyway.

Intake air temperature is not directly related to overheating of the engine. High intake air temps can lead to loss of power and detonation but that's a different issue than the original question of coolant temps. Colder and denser intake air makes more power because there's more oxygen, which means more heat is generated.

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[warmmilk]

100% agree. It was largely a copy / paste (with some minor modifications) designed to prioritize packaging purposes (see 10th gen 2.0 Accord / 2.0 TLX / 2.0 RDX, etc.).

We have the same problem with the cooling loop.

yeah but they could have been designed better in those applications as well... just cause its not a performance application doesn't mean intake temps don't matter

I'm personally not convinced the intake pipe routing is all to blame. The compression of the air in the turbo is responsible for much more heating than heat going into the intake pipe. PV=nRT and all that. The heat shield of the turbo is shielding the majority of radiant heat from it anyway.

Intake air temperature is not directly related to overheating of the engine. High intake air temps can lead to loss of power and detonation but that's a different issue than the original question of coolant temps. Colder and denser intake air makes more power because there's more oxygen, which means more heat is generated.

I'm not trying to say intake temps are causing the overheating issue, just that hot IATs are bad for power.

although there's a small affect... from the factory the car makes 315hp, its tuned to make 315, its tuned to compensate for a variety of factors to make 315. its easier to make 315hp when IATs are 90° vs 120° (arbitrary numbers picked to illustrate a point). at 120, the turbo has to work harder and therefore gets hotter, the intercooler gets hotter IAT air and therefore the cooling air coming off of it and going to the radiator is hotter, the combustion in the cylinders is hotter which makes the engine hotter, which puts more load on the radiator, the exhaust is hotter which makes the turbo hotter again, which heats the intake even more.
now if the IATs were 90° the turbo wouldn't have to work as hard, the intercooler wouldn't have to work as hard, the radiator would get slightly cooler air, combustion would be slightly cooler, exhaust temps would be slightly cooler...

but it is minor... we're talking maybe a couple degrees here. but then again there are people buying Acuity's reverse flow radiator hoses for a couple degrees for hundreds of dollars. I know I will if I end up buying an FL5.

and of course this all goes out the window once you tune the car and try to get every last hp (safely) out of the car instead of aiming for factory 315. cause then your turbo is back to working harder and everything making more heat... but you're also making more power for that same amount of heat...

I'm just a little bit of an efficiency nut. and this is just an inefficient design as far as temps and power goes. but as I type this I'm thinking there might me emissions and fuel economy (under normal driving) reason where a warmer IAT is better? prolly more emissions than fuel economy. Which would explain the design in the accord/rdx/etc. but then again, pretty much every other car out there OEMs make enclosed intake systems with ducts to fresh air and stuff...

 

[siwelnosaj]

Yeah IAT don't really have anything to do with engine overheating. I do agree that if the R was being built again from the ground up there are a few design features that could be changed to make the car run cooler both with regards to ECT/Oil and IATs.

All that aside it's what it is. I'm not sure how many of you come from the 10th gen/fk8 world but overheating is something that's been talked about extensively, and most simply could not solve the problem. The solution that seemed to be the most successful is really a holistic approach (increasing cool air in with a larger grill, increasing hot air exiting with a vented hood, secondary front mounted radiator which increases coolant volume and cooling surface area, single or more ideally a dual oil cooler set up to again increase fluid volume and surface area, not as critical but helpful to some degree is running an ethanol blend which burns a little cooler).

All aspects are important, but I would say the secondary radiator and oil coolers are the most important elements. Next would be air in and air out pathway.

The fl5 seems to do a solid job from factory with air in/air out with the mostly open grill and the small vent in the hood. I'm sure this can be improved with some of the aftermarket hood options, but it may not be necessary (I think it's still to early to know for sure at this point).

Talking with PWR they seem to think that the oil is the primary culprit and they are hopeful their front mounted oil cooler will do the trick. I think they are on the right track but I am unsure if it will be enough. I have no doubt their core is second to none, but as we saw on the fk8, everyone was running a single oil cooler in the lower fake vent area and it alone didn't really change the game.

From my own experience, along with several other people's experiences it was the introduction of the front mounted secondary radiator (along with an oil cooler or 2, and the other ancillary mods) that really tipped the scales. I really and truly believe it is critical to have supplemental direct cooling for both the coolant and oil to solve this problem.

The HRC DE5 tcx car developers seem to agree considering they are using a dual oil cooler set up along with a PWR race radiator with no AC condenser, as well as a seibon vented hood.

I will be testing to see if our fk8 secondary radiator kit can be made to work on the fl5, I'm waiting on it to arrive in the mail. My goal is to see if I can mount it to the OEM crash bar and have everything still fit and link up. We shall see. If this doesn't work there are still a couple of other ideas on this front that I'm sure will work.

Additionally we are working on a dual oil cooler set up that the average person would be willing to install. If we wanted the dead on best method we would just cut some holes and install some intake ducts to feed air to a pair of oil coolers, one on each side. But we know that most people won't be too keen on cutting big holes in their bumpers, so the challenge is providing air to said coolers with minimal modification. We are working on a couple of ideas at the moment and then will be testing. As mentioned in an earlier post I know that there's also a shop in the bay area who is developing a kit with a similar concept. I would image both will be in testing late this summer or in the fall at the latest. As mentioned PWR is about to release their core as well which might also do the trick.

All said, it's a matter of getting some oil coolers and possibly a secondary radiator in place to directly cool the hot fluids, this is for sure the most important factor. Add some hood vents or an aftermarket hood, and possibly an even more open grill and I think we'll be in about as good of a spot as we could realistically hope for (without removing the AC).

 

[ABPDE5]

yeah but they could have been designed better in those applications as well... just cause its not a performance application doesn't mean intake temps don't matter...
...I'm just a little bit of an efficiency nut. and this is just an inefficient design as far as temps and power goes. but as I type this I'm thinking there might me emissions and fuel economy (under normal driving) reason where a warmer IAT is better? prolly more emissions than fuel economy. Which would explain the design in the accord/rdx/etc. but then again, pretty much every other car out there OEMs make enclosed intake systems with ducts to fresh air and stuff...

This is exactly it. They have competing priorities -- performance, emissions, packaging, etc. When they design the platform, they have to make sure it fits in a variety of different engine bays and meets a variety of different emissions requirements, and it needs to be produced at the minimum possible price point (materials acquisition / inventory management, assembly, maintenance / repairs, etc.).

In fact, they are probably prioritizing bringing things up to temp ASAP not only for emissions, but also for reliability. Many owners will get right in their car on a frigid day and immediately call for peak torque as they exit the driveway while everything is still cold.

The system is more than sufficient for 99+% of Accord / TLX / RDX owners. Frankly, it's probably more than sufficient for 85+% of DE5 / FL5 owners -- if not more (the reality is most don't track their cars, and even among those that do, a large number don't push hard enough and / or reside in a warm enough climate to have issues).

Don't get me wrong: it bugs me that they implemented the intake and cooling systems the way they did on these cars. I wish they did otherwise. But... I understand why they did it.

The age of a bespoke powertrain implementation in a budget performance car is long gone. These cars are $45-52k with a mostly mass-produced platform. Additional hoses, radiators, oil coolers, pumps / valves, an entirely different intake design, cost accounting for managing addtl. assembly / maintenance training, inventory for assembly / repairs, addtl. warranty funding, etc. That cost is substantial.

While many of us on here posting on these forums and / or tracking our cars want a different solution... we're a small fraction of the market, and we still bought the cars anyway, so it's clear why they made the choice they did.

 

[Gansan]

OK I think we all agree in general. Yeah it would be nice if our cars were purpose designed for track use...like a Mercedes CLK GTR or something, but as @ABPDE5 says, the cost would be enormous and a money loser for Honda. The accountants would say no. Part of the value pricing in our cars is that it's a common car just with some nice modifications to make it pretty sporty and trackable.

Regarding cooling, I really don't like the secondary radiator solution if it's going to sit in front of the main radiator and blow hot air at it in addition to blocking airflow. It's just a super inefficient solution, even if it works. It would be nice if someone could come up with a nice exit duct which would greatly improve cooling...if only there wasn't a giant turbo in the way. hey, maybe that's a reason to want the turbo in the back.

 

[siwelnosaj]

OK I think we all agree in general. Yeah it would be nice if our cars were purpose designed for track use...like a Mercedes CLK GTR or something, but as @ABPDE5 says, the cost would be enormous and a money loser for Honda. The accountants would say no. Part of the value pricing in our cars is that it's a common car just with some nice modifications to make it pretty sporty and trackable.

Regarding cooling, I really don't like the secondary radiator solution if it's going to sit in front of the main radiator and blow hot air at it in addition to blocking airflow. It's just a super inefficient solution, even if it works. It would be nice if someone could come up with a nice exit duct which would greatly improve cooling...if only there wasn't a giant turbo in the way. hey, maybe that's a reason to want the turbo in the back.

Good luck with that...

The secondary option may not be the most sexy, but it works. It's blowing warmer air back, that's true, but overall you're still increasing cooling surface area as well as fluid capacity. Overall it's a net gain, and at the end of the day it works. Look up my times at Laguna and you'll see they are nearly 2 seconds clear of the next best fk8 and 4 seconds clear of the current fastest fl5. The numbers don't lie.

 

[Gansan]

Good luck with that...

The secondary option may not be the most sexy, but it works. It's blowing warmer air back, that's true, but overall you're still increasing cooling surface area as well as fluid capacity. Overall it's a net gain, and at the end of the day it works. Look up my times at Laguna and you'll see they are nearly 2 seconds clear of the next best fk8 and 4 seconds clear of the current fastest fl5. The numbers don't lie.

Your fast times aren't proof the car is fast because of the radiator. It means YOU'RE fast.

I believe you when you say it works. The engineer in me can still dislike it

 

[siwelnosaj]

Your fast times aren't proof the car is fast because of the radiator. It means YOU'RE fast.

I believe you when you say it works. The engineer in me can still dislike it

It's fair to dislike it, and no it doesn't make me fast over a singular lap, but when I say the numbers don't lie, I don't just mean the lap times, I also mean the temps I'm getting while getting those lap times while running full sessions as compared to others running slower times and only getting a few laps.

The coolant and oil temps compared to others, especially when you consider that I'm running times that are significantly faster than their times, it all adds up to the fact it's working.

Again, you can dislike it, but it works and at this point given how many fast fk8 guys are running it, it's not just me saying it.

But I get it, it was like this a few years ago when I first created the set up, a lot of people doubted the concept, but just like last time I think you'll see in time this ends up being the way to go.

 

[BuntaTypeR]

I haven´t tested the latest setup at the track, but another addition I made, other then the PWR and the HEL oil cooler, was divorcing the transmission from the water system.

Main reason for that is to remove parallel systems.

Keep in mind that if you plug all parallel systems and still run a thermostat, shit will happen.

now there is an oil cooler for the trans.

Also ordered this from... CHINA lol

this will probably take forever to arive, but at some point it will


I´ll let you know if it really helps

did you receive this hood? im thinking of getting it.

 

[Rhorn]

did you receive this hood? im thinking of getting it.

I wish there were some carbon fiber hoods that are color matched. The vents could be carbon fiber but I'm not a fan of having it all black espically since the goal is to reduce heat not attract it lol.

 

[siwelnosaj]

I wish there were some carbon fiber hoods that are color matched. The vents could be carbon fiber but I'm not a fan of having it all black espically since the goal is to reduce heat not attract it lol.

You just have to have your local body shop paint match it

 

[BuntaTypeR]

I wish there were some carbon fiber hoods that are color matched. The vents could be carbon fiber but I'm not a fan of having it all black espically since the goal is to reduce heat not attract it lol.

i feel the same way.
i do know that those vents will help. i know there's a car at the track who has a 1 vent and it was overheating. he put 3 vents using this https://racelouvers.com/ and it lowered the temp significantly. it lowered the engine temp by 20F to 30F!

although, installing these vents in my hood will look ugly https://racelouvers.com/

https://racelouvers.com/civic-17-22-type-r-xl-center-hood-louver-rt-track-trim/

 

[siwelnosaj]

i feel the same way.
i do know that those vents will help. i know there's a car at the track who has a 1 vent and it was overheating. he put 3 vents using this https://racelouvers.com/ and it lowered the temp significantly. it lowered the engine temp by 20F to 30F!

although, installing these vents in my hood will look ugly https://racelouvers.com/

https://racelouvers.com/civic-17-22-type-r-xl-center-hood-louver-rt-track-trim/

This is the hood the thrw 25h team used, and the de5 tcx cars are using.

https://www.procivic.com/pages-prod...pQaEPQZCevaWdV2CGDEn49R68B5EC-whoC5a8QAvD_BwE

 

[Rhorn]

Does changing the hood really reduce temperatures? I dont know about alot about areo and the mechanics behind the venting so idk really if the vents are actually working

 

[siwelnosaj]

Does changing the hood really reduce temperatures? I dont know about alot about areo and the mechanics behind the venting so idk really if the vents are actually working

I can say conclusively that if designed correctly the vents do work. I don't have data on it, but a lot of prominent race teams do it and they usually only operate on a basis of what's fast and effective.

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