FL5 Overheated on Track

siwelnosaj

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11th Gen Honda Civic FL5 Overheated on Track FB_IMG_1744309943039


I want to share some pretty exciting news for the Type R track community! I have been working with PWR over the past couple of months and they/we will be releasing 2 versions of a triple pass radiator for the FL5 (and possibly the FK8 depending on demand).

One version will be the PWR version, and the other will be the WOT Performance by PWR version. I'm going to call it WOT spec for short.

In a general sense they will be very similar in design and concept, and both should perform extremely well. The triple pass design forces the coolant to travel along a longer path within the core, allowing it a longer period of time to cool down before traveling back towards the engine.

The WOT spec will have two primary differences:

1) More track oriented custom core spec: higher fin density, and special fin louver angle to further improve heat transfer.

2) Integrated bracket for optional transmission cooler: Built in provision on the back side of the radiator to easily add an optional transmission cooler to further reduce coolant temps by unburdening the coolant system (the OEM design uses the coolant system to cool trans fluid via the heat exchanger on the front of the transmission). The placement on the backside of the radiator is to minimize interference with the radiator and maximize efficiency.

The idea is that the PWR spec will be a massive step forward from the current track spec single pass that's available, and WOT spec will be the ultimate level stock replacement radiator available.

Both the PWR spec and WOT spec should be available in the coming weeks. Official pricing is still yet to be determined but should be in the $1400ish range (plus shipping) for the PWR spec, and $1600ish (plus shipping) for the WOT spec, with the transmission cooler add add on available for around $200.

The core of both specs will be 42mm (same as the current PWR track spec single pass radiator), and the other dimensions will also be similar with some slight changes to accommodate the different end tanks. Both specs will be a direct bolt on and will work with OEM fans and other components.

If you would like to pre-order either spec to be one of the first with this on your ride contact me. I will be the only vendor offering the WOT spec.

The picture in the post is a stock photo of the PWR track spec single pass radiator, currently there are no images yet available, but as soon as there are I will add them.

I recently hired someone to help me finish designing my website and it should be up and running here soon.
 

west357

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Has anyone just removed the trans cooler/heater and then tracked the car in warm temperatures? Also how involved is the modification? My car is 100% stock under the hood and I’m contemplating doing this first. My local shop has recommended starting here (they support an extremely fast time attack Honda civic that laps 1:24s at Mid Ohio). So I do think they know what they are talking about.
 

svvitch

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I don't know the temp trans fluid reaches on track. But plenty of Honda transmissions without coolers. I feel this was installed to warm the fluid in cold climates vs cooling the fluid on track.

Cold fluid probably reduces efficiency in cold climates and simply takes to long to warm up without the cooler/heater.
 

siwelnosaj

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Has anyone just removed the trans cooler/heater and then tracked the car in warm temperatures? Also how involved is the modification? My car is 100% stock under the hood and I’m contemplating doing this first. My local shop has recommended starting here (they support an extremely fast time attack Honda civic that laps 1:24s at Mid Ohio). So I do think they know what they are talking about.
That could make sense on a time attack car but I would be worried about the trans fluid getting too hot and also not getting proper warm up with the method used. I can't say for sure but those would be my concerns.

With my kit you'll have 2 options for install. Bypassing the piece you are talking about which would unburden the coolant system completely, but it also means you won't have the OEM warm up design of using coolant to warm the trans fluid (really just depends on your climate and use plans)

The other would have the trans cooler tap into the OEM piece so that warm up still happens via coolant, but the supplemental cooler helps significantly with trans fluid temps and the coolant system doesn't have to carry the load.

For what it's worth the TCR cars also use a transmission cooler. Time attack makes sense cause it's 1 or maybe 2 hot laps usually and then the cool down. They usually don't even need much in the way of cooling mods
 
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siwelnosaj

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The physical units are being built currently but here is the final design of the FL5 WOT spec triple pass radiator with transmission cooler! There is also an FK8 version in production and it will in essence be the same with different mounting points specific to the FK8.

PWR will also be releasing their own spec here soon. The WOT spec will have two primary differences:

1) More track oriented custom core spec: higher fin density, and special fin louver angle to further improve heat transfer.

2) Integrated bracket for optional transmission cooler: Built in provision on the back side of the radiator to easily add an optional transmission cooler to further reduce coolant temps by unburdening the coolant system (the OEM design uses the coolant system to cool trans fluid via the heat exchanger on the front of the transmission).

The placement on the backside of the radiator is to minimize interference with the radiator and maximize efficiency.

The idea WOT spec will be the ultimate level stock replacement radiator available.

This will fit just like the current PWR single pass radiator. No modifications needed, works with the fan and works with various intakes.

If you would like to order either spec contact me and I can set your order up. I will be the only vendor offering the WOT spec.

Price is $1600 without the transmission cooler attached (but can add it later since the bracket is on), $1800 with the transmission cooler, lines, and clamps. $120 for shipping, so $1720 or $1920 depending.

PWR spec will be $1400 plus $120 for shipping so $1520.

You have the option to plumb the transmission cooler in 2 ways: 1 is to integrate it with the OEM heat sink piece to maintain OEM warm up using coolant, or #2 is to completely bypass the OEM heat sink but at the cost of losing OEM warm up.

FK8 version will require the removal of the passenger side fan, but in talking with the PWR engineering team they feel confident this will cause no issues on the street and on the track it will actually help by removing resistance on the back side. I ran my FK8 daily and track for 2 years without the passenger side fan with zero issues even in 105+ temps in the Reno summer.

11th Gen Honda Civic FL5 Overheated on Track Screenshot_20250425_073900_Drive
11th Gen Honda Civic FL5 Overheated on Track Screenshot_20250425_073928_Drive
11th Gen Honda Civic FL5 Overheated on Track Screenshot_20250425_073958_Drive
11th Gen Honda Civic FL5 Overheated on Track Screenshot_20250425_074018_Drive
11th Gen Honda Civic FL5 Overheated on Track Screenshot_20250425_074045_Drive
 

siwelnosaj

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11th Gen Honda Civic FL5 Overheated on Track Apr-27-2025-Speed Ventures (Sun)-Red Group-Session 2 (Turn 2)-CPRP5092_Apr2725_839AM_CaliPhoto~2
11th Gen Honda Civic FL5 Overheated on Track Apr-27-2025-Speed Ventures (Sun)-Red Group-Session 1 (Turn 3)-CPRP4150_Apr2725_705AM_CaliPhoto~2
11th Gen Honda Civic FL5 Overheated on Track On Track Oil Temperature Comparison-1
11th Gen Honda Civic FL5 Overheated on Track On Track Coolant Temperature Comparison-1
11th Gen Honda Civic FL5 Overheated on Track FB_IMG_1745866505787
11th Gen Honda Civic FL5 Overheated on Track FB_IMG_1745866788162


Massive results during track testing yesterday!

Dual oil cooler set up is working and working well. Still need to make a couple of small adjustments on fitment and finalize brackets, but given yesterday's results with the prototype, it showed it's ready to perform. Hopefully I can get these adjustments made in the next few weeks and officially put the kit up for sale. Best part is you can't even see that there's oil coolers on the car, OEM+. I'll share pictures when it's ready for sale.

Testing was done in 2 parts. Saturday ran with no oil coolers, no cooling plate, OEM radiator. Sunday I added the oil coolers and later the cooling plate. Ambient temps were low at 62°, but this testing was about relative performance, 1 for 1. Oil temps were measured using a physical sensor added into the oil pan (post engine and pre oil coolers so it's at its hottest). Coolant was measured using the OEM sensor in the head.

On Saturday to create a baseline, the car was run in OEM cooling form (OEM radiator, OEM under tray, no oil coolers) I got the car to the limit with a peak oil temp of 290° and coolant up to 249°. This was in a session where I had my last 5 laps averaging 1:55.66 on the new Buttonwillow "The Circuit".

Sunday with the oil coolers added, peak temps dropped to 255° for oil and 219° for coolant. In this session I had the last 5 average 1:55.21. A giant 35° improvement in post engine oil temps, and 30° in coolant temps!

When the cooling plate was added, peak temps dropped again with oil at 249° and coolant down to 206°. Last 5 laps averaging 1:54.41. Another drop of 6° for oil, and 13° for coolant!

I experienced zero aero issues with the cooling plate added, I achieved my highest top speeds and highest lateral Gs with it on the car, 128.4 mph and 1.46 G respectively.

I will be returning to The Circuit in 2 weeks to run the WOT spec triple pass radiator and transmission cooler and I'm hopeful ambient temps will be in the 80s or 90s to show that the whole suite of cooling items collectively can get the job done in the heat!

Once I've finalized everything on the FL5 I will be working on releasing the kit for the DE5 and FK8. All 3 cars will have the same modifications available to them.
 

Rhorn

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Apr-27-2025-Speed Ventures (Sun)-Red Group-Session 2 (Turn 2)-CPRP5092_Apr2725_839AM_CaliPhoto~2.jpg
Apr-27-2025-Speed Ventures (Sun)-Red Group-Session 1 (Turn 3)-CPRP4150_Apr2725_705AM_CaliPhoto~2.jpg
On Track Oil Temperature Comparison-1.jpg
On Track Coolant Temperature Comparison-1.jpg
FB_IMG_1745866505787.jpg
FB_IMG_1745866788162.jpg


Massive results during track testing yesterday!

Dual oil cooler set up is working and working well. Still need to make a couple of small adjustments on fitment and finalize brackets, but given yesterday's results with the prototype, it showed it's ready to perform. Hopefully I can get these adjustments made in the next few weeks and officially put the kit up for sale. Best part is you can't even see that there's oil coolers on the car, OEM+. I'll share pictures when it's ready for sale.

Testing was done in 2 parts. Saturday ran with no oil coolers, no cooling plate, OEM radiator. Sunday I added the oil coolers and later the cooling plate. Ambient temps were low at 62°, but this testing was about relative performance, 1 for 1. Oil temps were measured using a physical sensor added into the oil pan (post engine and pre oil coolers so it's at its hottest). Coolant was measured using the OEM sensor in the head.

On Saturday to create a baseline, the car was run in OEM cooling form (OEM radiator, OEM under tray, no oil coolers) I got the car to the limit with a peak oil temp of 290° and coolant up to 249°. This was in a session where I had my last 5 laps averaging 1:55.66 on the new Buttonwillow "The Circuit".

Sunday with the oil coolers added, peak temps dropped to 255° for oil and 219° for coolant. In this session I had the last 5 average 1:55.21. A giant 35° improvement in post engine oil temps, and 30° in coolant temps!

When the cooling plate was added, peak temps dropped again with oil at 249° and coolant down to 206°. Last 5 laps averaging 1:54.41. Another drop of 6° for oil, and 13° for coolant!

I experienced zero aero issues with the cooling plate added, I achieved my highest top speeds and highest lateral Gs with it on the car, 128.4 mph and 1.46 G respectively.

I will be returning to The Circuit in 2 weeks to run the WOT spec triple pass radiator and transmission cooler and I'm hopeful ambient temps will be in the 80s or 90s to show that the whole suite of cooling items collectively can get the job done in the heat!

Once I've finalized everything on the FL5 I will be working on releasing the kit for the DE5 and FK8. All 3 cars will have the same modifications available to them.
Doing the Lords work 🙏

Always love it when the fan passion projects outdo billion dollar companies 👏

You should change your username to Type R Jesus 😅
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