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DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)?

keller

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Went down a long rabbit hole of YouTube videos and HPD catalogs, and the common theme is the following;

1) Airflow really matters. Most of the hoods have extra vents. At the very least, they don’t have the rain shields.

2) They all have OE or OE style tube and fin intercoolers

3) They’re feeding aux oil coolers with fresh air that doesn’t interfere with radiator cooling.
And:

4) Separate coolers for transmission fluid

Also we can't forget all these race cars don't have ACs. It's the single most effective cooling mod. The AC condenser sits in front of the radiator and increases the total air resistance - a lot less air travel through the engine bay because of it. The ultimate proof is the BTCC FK8 race car (pic below). It has 350bhp, stock-ish grill and stock hood with some laughably small lateral vents. It doesn't overheat, ever. But this would never work on a street FK8 with an AC, a stock crash bar and fans+shrouds. What I mean is that we can't easily translate race car solutions to our road going cars. We need much more extensive mods than them. And as soon as we get close to dealing with the heat issue, we bump the power level another 20-30% (race regulations don't allow them to do it!) and we have to go back to the drawing board haha.

Anyway, I agree completely with your observations. They are a common theme with the fk8 crowd. Large bar&plate ICs and front-mounted oil coolers have only made it worse.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? btcc_050
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tezzasaurusrex

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Have you ever driven an FK8 on track? This behavior of the suspension is exclusive of the FL5? I might just be so far away from the limit that I haven't noticed it haha.

It's sad you are close to ditching the ADS for coilovers because of it. For me, the Type R is so special because it's both a great daily and a somewhat capable track car. I'm working on a way to tune my FK8 ADS controller. I'm getting tired of having to replace the original ADS unit every trackday for the LE ADS. I simply can't use the LE ADS on the street because it's so damn stiff.
I haven't driven an FK8 on track, only around the street and I can't say I remember a whole lot about the experience. I think the bouncing is exclusive to the FL5 - I've not seen it in any other Honda platform out of the factory.
Thankfully, the Ohlins DFV is so capable that I don't think I'll be missing the adjustable suspension modes at all, especially since I never adjust it anyway cause comfort is the only mode I use. The ability to easily change spring rates will also be a welcome addition.
It would be amazing if you can find a way of tuning the ADS system yourself - you could turn the OEM suspension into an entirely different beast altogether likely more capable than any other aftermarket solution.
 

Dennis

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It's sad you are close to ditching the ADS for coilovers because of it. For me, the Type R is so special because it's both a great daily and a somewhat capable track car. I'm working on a way to tune my FK8 ADS controller. I'm getting tired of having to replace the original ADS unit every trackday for the LE ADS. I simply can't use the LE ADS on the street because it's so damn stiff.
Maybe you can make a plug and play harness with some relays in it, in order to leave both ECUs installed into the car and switch between them using a button.
 

keller

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It may just be an illusion but it looks almost as though the engine has tilted back some to make way for the V mount set up on the TCR.
On Sunday I'm going to a TCR race with pit lane access. Coincidentally just today I received this picture that shows exactly what I wanted to see haha. Indeed the engine seems tilted back. I can't even see the left engine mount.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? IMG_20231019_153130_670
 

tezzasaurusrex

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On Sunday I'm going to a TCR race with pit lane access. Coincidentally just today I received this picture that shows exactly what I wanted to see haha. Indeed the engine seems tilted back. I can't even see the left engine mount.
Amazing, get all the photos you can get! Bring a zoom lens hahaah

Yeh makes sense, I think TCR mandates a 60/40 weight distribution which is a little further back than what the stock car is (which is 62/38) - the tilting of the engine should help some, and then plus all the cage work would bring it to 60/40. FWIW I don't believe this to be the better way to set up a FWD - I prefer something closer to 65/35
 
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keller

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FWIW I don't believe this to be the better way to set up a FWD - I prefer something closer to 65/35
You know you shouldn't just make us curious and not explain us the reason right? :p

Amazing, get all the photos you can get! Bring a zoom lens hahaah
Not really needed haha. Took a lot of short videos, mostly from the FK8s though. I will open a new thread on civicx and upload them in the coming days!

Lots of anti tempering wires. One of them on the valve cover, so teams can't just install new cams haha. These are from the FL5. They were replacing the transmission fluid. There was a quick connect hose at the strut bar/roll cage to make the process really fast.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? IMG_20231022_103013465_HDR
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? IMG_20231022_103648253
 

tezzasaurusrex

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You know you shouldn't just make us curious and not explain us the reason right? :p
Haha its only my opinion thus cannot be taken as gospel, but my thinking is based on a design of fwd where inertial moment is not the goal but a foward bias mass to maximise front grip. The result is a fwd that doesn't have the best handling dynamics per se but is focused on purely going fast.

Not really needed haha. Took a lot of short videos, mostly from the FK8s though. I will open a new thread on civicx and upload them in the coming days!
Lots of anti tempering wires. One of them on the valve cover, so teams can't just install new cams haha. These are from the FL5. They were replacing the transmission fluid. There was a quick connect hose at the strut bar/roll cage to make the process really fast.
Thats awesome, makes good sense as you'd only need to run a metric to AN fitting adaptor to replace the factory filler plug and fill the amount they drain (saving them from having to remove the little m6 fluid check plug at the front of the transmission). I assume they've removed the factory water/oil heat exchanger for a dedicated transmission cooler mounted on the left side of the intercooler - not sure if you managed to catch a glimpse of this.
Will keep my eyes peeled for the thread on the civicX :)
 

tezzasaurusrex

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Just thought I'd share some cooling system diagrams comparing our cars and the system on the BMW M3/4 S58 engine.

FK8/FL5
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? FK8 Cooling Diagram


S58
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? S58 Cooling.JPG


Our system relys on a single front mount radiator (not including the heater core) to cool the engine and both the engine oil and the transmission fluid.
The S58 on the other hand has a seperate air/oil cooler for the engine oil, 4 seperate frontal radiators for the water, and a water/oil cooler for the transmission fluid - which equates to a total of 6 cooling elements!
Granted - the S58 is producing more power and it runs a water/air charge cooler, but the supporting cooling system is light years ahead in terms of cooling capacity.
On a more comparative level, the Golf R has 3 seperate radiators for the water system and produces about the same power as the K20C1 - only I couldn't find a cooling system diagram online.

Moral of the story - we need more radiators people.
 

keller

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Just thought I'd share some cooling system diagrams comparing our cars and the system on the BMW M3/4 S58 engine.

FK8/FL5
FK8 Cooling Diagram.png


S58
S58 Cooling.JPG


Our system relys on a single front mount radiator (not including the heater core) to cool the engine and both the engine oil and the transmission fluid.
The S58 on the other hand has a seperate air/oil cooler for the engine oil, 4 seperate frontal radiators for the water, and a water/oil cooler for the transmission fluid - which equates to a total of 6 cooling elements!
Granted - the S58 is producing more power and it runs a water/air charge cooler, but the supporting cooling system is light years ahead in terms of cooling capacity.
On a more comparative level, the Golf R has 3 seperate radiators for the water system and produces about the same power as the K20C1 - only I couldn't find a cooling system diagram online.

Moral of the story - we need more radiators people.
This is amazing. I looked for this same S58 doc and the explanation for each cooling circuit is just so cool to read. To be fair, since 2 of their frontal radiators are for charge air cooling, we should count our IC and say we have 2 cooling elements. Still a bit short hahaha

More importantly, their engine doesn't use a headifold design - they have proper exhaust manifolds! This should considerably lower the rejected power going into the engine coolant fluid.

I looked for info on the Golf R just the other day and I found mentions that only the DSG had 3 frontal radiators, one of them being for the transmission. The MT model only had 2. Is this correct? I'm considering purchasing an OEM Golf R aux cooler to install on the fk8 side vents. It's cheap and it seems to fit the available space.

Now, regarding your last point. Jason Lewis has an ad hoc aux radiator solution that supposedly can handle the overheating issue even for tuned fk8s. A few guys have copied him with great results. Recently a Singaporean company started manufacturing a complete kit based on his design, but with a few (maybe critical) changes. Jason received a test unit that he's going to test on track next weekend. Meanwhile, I have also talked to an fk8 owner on ig that has this exact kit. He told me that at least now he can push for 1 full hot lap in Sepang Intl Circuit, but not 2 hahaha. And that's with all the cooling mods we can think of. So now I'm waiting for Jason's impressions before purchasing it because I'm worried their changes might have been for the worse.

I have a question for you. I know the FL5 OEM radiator is larger than the FK8 radiator, but not by that much. However the coolant capacity has increased a lot! Is it because of the radiator alone?

FK8:
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? Screenshot from 2023-10-24 03-22-13


FL5:
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? Screenshot from 2023-10-24 03-22-32
 

keller

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Thats awesome, makes good sense as you'd only need to run a metric to AN fitting adaptor to replace the factory filler plug and fill the amount they drain (saving them from having to remove the little m6 fluid check plug at the front of the transmission). I assume they've removed the factory water/oil heat exchanger for a dedicated transmission cooler mounted on the left side of the intercooler - not sure if you managed to catch a glimpse of this.
Will keep my eyes peeled for the thread on the civicX :)
The TCR CTR uses a sequential transmission, so the factory transmission heat exchanger is not there. I could easily see the small transmission cooler on the FK8 TCR, but not on the FL5 - even though the brochure in post #1 says the FL5 should have one. Could this be the reason they changed the FL5 transmission fluid between races and not of the FK8s?

Everything was so quick because the mechanics had to work on the cars before the next race that happened like 1h later. Most of the time of the visit the cars had their hoods down. On the last 10 minutes the mechanics started working on them and then I managed to get a few short videos of the engine bay and wheel wells, trying to annoy them as little as possible before I had to go upstairs to the paddocks.

I'm probably just uploading everything to a google drive because the forum won't allow me to upload such large files =/

So, this race happened on a circuit called Velo Citta, which is a fairly technical circuit with lower top speed. Coincidentally, my last trackday was exactly at this race track. My wife was driving her Civic Si that we had just installed parts and set up for better rotation. We have been training with our race car that is a hilariously loose car. From the paddocks, it was nice seeing her rotating so easily around those corners. Our instructor also drove my fk8 and told me the Si was rotating a lot easier.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? VID_20231022_090906043_exported_9525


Now, during the afternoon TCR race I was at the same spot at the paddocks and could see a few cars struggling to rotate at the very same corners that I happened to see my wife's Si doing so easily. One of them was the only FL5 on the grid. Later I learned that that FL5 was the slowest car on the qualifying session (+1.5s).

When the mechanics lifted the cars and removed the wheels, I quickly realized the FL5 was "missing" a rear sway bar. It has 3 adjustable positions, so it's adjusted to the driver's preference for each track. But there was no endlink there - I can only assume the driver asked it that way. No wonder he seemed to be struggling to rotate. The other 3 FK8s were all set up with some RSB setting.

What motivated me to write about this is where the RSB was located (see below). JAS put it going through inside the cabin hahaha. On the left you can see a ride height potentiometer.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? VID_20231022_103311460_exported_2306


Since I can't allow my wife's Si to rotate better than my fk8 haha, I recently ordered 2 sets of Karcepts RSBs. They look just like this JAS RSB, but they mount on the factory position.
 


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Just thought I'd share some cooling system diagrams comparing our cars and the system on the BMW M3/4 S58 engine.

FK8/FL5


S58


Our system relys on a single front mount radiator (not including the heater core) to cool the engine and both the engine oil and the transmission fluid.
The S58 on the other hand has a seperate air/oil cooler for the engine oil, 4 seperate frontal radiators for the water, and a water/oil cooler for the transmission fluid - which equates to a total of 6 cooling elements!
Granted - the S58 is producing more power and it runs a water/air charge cooler, but the supporting cooling system is light years ahead in terms of cooling capacity.
On a more comparative level, the Golf R has 3 seperate radiators for the water system and produces about the same power as the K20C1 - only I couldn't find a cooling system diagram online.

Moral of the story - we need more radiators people.
Wow, you can really see just how barebones the K20C1 is compared S58. I think the K20C1 was the first real high performance turbocharged engine Honda put out so maybe they just don't have the same experience as BMW since they have been on forced induction for awhile now. But the K20C1 has been out for 2015 so hard to not see why they didn't invest in better cooling. For how small I4s are its kind of ironic that I don't even think you could fit all of those coolers in the engine bay lol.

I was curious to actually see the cooling diagrams of other similar engines to the ours. I looked at the G16E-GTS (GR Corolla) and it seems pretty barebones too. I'm not in any GRC circles so I wonder if that has engine overheating issues too. I know it the differential can overheat and will keep the car in 60/40 FWD mode.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? 1698156485864

1 - water inlet housing with water pump, 2 - throttle body, 3 - reserve tank, 4 - water outlet housing, 5 - turbocharger, 6 - radiator, 7 - oil cooler, 8 - thermostat. a - from heater radiator, b - to heater radiator

This is the source incase anyone wants to go digging
 

tezzasaurusrex

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I looked for info on the Golf R just the other day and I found mentions that only the DSG had 3 frontal radiators, one of them being for the transmission. The MT model only had 2. Is this correct? I'm considering purchasing an OEM Golf R aux cooler to install on the fk8 side vents. It's cheap and it seems to fit the available space.
Yes you are correct on this one, the MT Golf R has 2 coolers instead of 3 like the DSG variant.

I have a question for you. I know the FL5 OEM radiator is larger than the FK8 radiator, but not by that much. However the coolant capacity has increased a lot! Is it because of the radiator alone?
I can't say for sure - it does appear to be a huge capacity increase (2.1L) according to the spec you quoted. Not sure how that translates to real life as from what I can see there's really not an awful lot that has changed except the main thing being the FL5 radiator is positioned a few inches further forward and away from the engine compared to the FK8 and the airflow design structure change (FL5's bonnet vents out), There won't be a 2.1L difference in radiator capacity thats for certain.
 

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I think comparing our cars to the similar class of car (GR Corolla) is appropriate.

It’s not really fair to compare cooling packages to a much larger displacement, significantly heavier, and more costly car (G80 BMW).

It’s obvious that weight and cost/complexity were not a concern for BMW. It costs nearly double the MSRP and weighs almost 900lbs more.
 

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I just noticed they are running the factory intercooler in the V mount set up. Amazing.
Did you see the brake caliper position in this picture? They inverted it from the FK8 TCR!

I assumed it was the OEM intercooler when I saw the plastic end tanks, but was not sure. The intake is also interesting - it doesn't have that aluminum inlet pipe over the turbo. It's a hose that travels right behind the crash bar and collects air (without a visible filter!) from the right side of the grill with a plastic deflector:

Back to the topic, here's a pic of an FL5 TCR car:
11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? fuus7hkwwaq-jaa-1-
Lol look at the brake calipers on this picture at JAS. The caliper was always mounted behind the axle! I only noticed it at the track.

The radiator is actually small, just slightly tilted back. I'd say smaller than OEM, and it's crossflow! It has one small fan and no shroud.

11th Gen Honda Civic DE5 HPD/JAS Motorsport TCR - What cooling modifications were done (comparison to the HPD FK8)? IMG_20231022_102115468_HDR


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