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

[tezzasaurusrex]

Yup. It seems like a billet knuckle like that one you linked once. Did you notice the rear spring is mounted around the shocks?

From their website:

Ah yes I did notice that they ditched the divorced spring set up. I suspect done to save weight (as you can run a lighter rate spring on a 1:1 motion ratio). Also interesting to see how small the rear brakes rotors are... Makes me ask the question of if we really need to do the 350mm rear rotor upgrade? Very cool stuff

 

[keller]

Ah yes I did notice that they ditched the divorced spring set up. I suspect done to save weight (as you can run a lighter rate spring on a 1:1 motion ratio). Also interesting to see how small the rear brakes rotors are... Makes me ask the question of if we really need to do the 350mm rear rotor upgrade? Very cool stuff

Lol they are 258mm against our 304mm rotor, they are really small. I had noticed this when I first saw an RS3 TCR on a trackday.

 

[tezzasaurusrex]

Lol they are 258mm against our 304mm rotor, they are really small. I had noticed this when I first saw an RS3 TCR on a trackday.

Its really quite baffling! It doesn't quite compute in my head, especially considering how big the front's are.. I guess these TCR's do spend a lot of time on 3 wheels, often times lifting the inside rear!

 

[keller]

Its really quite baffling! It doesn't quite compute in my head, especially considering how big the front's are.. I guess these TCR's do spend a lot of time on 3 wheels, often times lifting the inside rear!

I managed to follow his RS3 one day and it lifted one rear wheel every tight corner. Unknown to me at the time, he uses used hard slicks on shakedown/training sessions. I managed to keep with him the whole technical session of the track, what I assume only happened because I had better tires that day. His lap times on trackdays are 4s better than my PB. Which turns to 14s on qualifying sessions hahaha. By the way, if anyone is interested, I can find an onboard video of an FK8 TCR a driver recorded at my local track.

One thing I found interesting the last time I went to a TCR race is that they swap tires right before the race starts. They leave the boxes, do 1-2 laps through the pit lane, swap tires front and back, then do the final outlap to stop at the starting grid. This pilot I once talked to mentioned they have a hard time keeping their rears heated.

Back to the topic, I don't think the fact it often raises one wheel is the reason for less braking force on the rears. I believe they wouldn't decide on the brake force bias considering a condition that only happens mid corner. But that brake bias indeed is interesting!

 

[Rhorn]

Could the reason for the smaller rear brakes in the rear be for getting more rotation and get some oversteer under braking because these cars are still FWD? Seems like that would make sense since having larger wheels up front and smaller wheels in the rear does make a FWD car more oversteer prone.

Also one thing I just noticed with the TCR is that from the hood pics it doesn't look like a V setup? With the canted radiator I don't see any auxiliary coolers. There's a TCR in the background and there isn't really anything on the passenger side of the hood. There are two massive pipes that look like it could be an intake for something in that area though (if you look closely you can see just the other inlet pipe on the passenger side), its partially covered by the black tarp so its hard to makeout what exactly is going on in that area.

 

[Rhorn]

Yeah, it should be fun. Each team is 4-8 pilots, plus a couple mechanics to fix things at the track. People basically bring a full car in spare parts. Half the cars break down and quit the race, most of the other half will go through 1-2h long maintenance on the pit floor. It's cool for beginner pilots (like us) because you get to race yet driving skills aren't the most important factor for success, the reliability of the car is. You don't need to defend/attack positions, just maintain a healthy pace avoiding extreme stress on car parts. It's a multi class race: from prototypes and gt3 cars to my shitbox. It starts at midnight, so it's a night of redbull and pizzas among friends in an amazing F1 race track. Our friends have participated before, my wife and I are the rookies of the team lol.

Wow yeah that seems really fun. I always found it a bit jarring to be in a race car turn after turn doing it for that long. That's why I always found the Nürburgring 24 Hours to be so brutal. My only endurance experience has been doing those races on Gran Turismo and I crash after lap 3 lol. You need really good concentration. You basically just have to stay alive lol. Must feel good being part of a team like that though.

That's just a kit anyway, one could build that with common parts. The good thing is that they test fit everything and it comes with molded hoses. I have seen very few reports of the FL5 running hot so far, so maybe there isn't a market for kits like this? I think Baxi was the fist guy to outright claim it overheats, but now that I've seen his video that was obviously expected. Let's see how he fixes it.

Yeah thats true. It would be nice though for people that are less mechanically inclined like just lazy like myself Idk if he posted on IG yet but he just released a video on YouTube. Apparently the turbo literally blew up and now there's oil everywhere. Idk much about installing turbos but he said he thinks one of the AV cooling lines popped off of the turbo and that caused it to just get hotter and hotter before exploding. That sucks really bad lol.

As a curiosity, the "FK8 TCR" is actually an FK7 and (at least) the inlet pipe is from an FK2. They just slapped a Type R logo on the back haha.

Oh yeah good info, thats what the HPD guy was telling me about the FK8 TCR. JAS still makes FK2 TCRs so there is alot of carryover in design, do you know what's attached to the radiator in the FK8 TCR? Looks like an additional cooler or something but its not in the FL5 TCR

 

[keller]

Could the reason for the smaller rear brakes in the rear be for getting more rotation and get some oversteer under braking because these cars are still FWD? Seems like that would make sense since having larger wheels up front and smaller wheels in the rear does make a FWD car more oversteer prone.

Also one thing I just noticed with the TCR is that from the hood pics it doesn't look like a V setup? With the canted radiator I don't see any auxiliary coolers. There's a TCR in the background and there isn't really anything on the passenger side of the hood. There are two massive pipes that look like it could be an intake for something in that area though (if you look closely you can see just the other inlet pipe on the passenger side), its partially covered by the black tarp so its hard to makeout what exactly is going on in that area.

You can tell it is a V setup because the intercooler and radiator aren't mounted upright in the engine bay. Note how both of them receive fresh air. Those pipes on each side are brake ducts.

Regarding the smaller rear rotor, my guess is they don't need a large rotor diameter to maintain close to the same brake bias. Their rear caliper seems to have a much larger piston area (2 pistons!) and the car has adjustable brake proportioning valves. Also, these race cars tend to be more front heavy than our road cars.

It's interesting how different the hoods are. They increased the original FL5 hood vent and added 2 new lateral vents. The FK8 TCR only has 2 large lateral vents.

 

[keller]

Wow yeah that seems really fun. I always found it a bit jarring to be in a race car turn after turn doing it for that long. That's why I always found the Nürburgring 24 Hours to be so brutal. My only endurance experience has been doing those races on Gran Turismo and I crash after lap 3 lol. You need really good concentration. You basically just have to stay alive lol. Must feel good being part of a team like that though.



Yeah thats true. It would be nice though for people that are less mechanically inclined like just lazy like myself Idk if he posted on IG yet but he just released a video on YouTube. Apparently the turbo literally blew up and now there's oil everywhere. Idk much about installing turbos but he said he thinks one of the AV cooling lines popped off of the turbo and that caused it to just get hotter and hotter before exploding. That sucks really bad lol.

Just watched his video, thanks. Considering what happened, that's not so bad. Bad turbo installation (assuming that is what happened, since AN fittings are supposed to be super reliable) could have resulted in fire. It still makes a grown man cry though.

Honestly, I believe he's rushing things. The fact there are many parts from the FK8 readily available probably made him want moaaar before it was wise to do so.

Oh yeah good info, thats what the HPD guy was telling me about the FK8 TCR. JAS still makes FK2 TCRs so there is alot of carryover in design, do you know what's attached to the radiator in the FK8 TCR? Looks like an additional cooler or something but its not in the FL5 TCR

That is a transmission fluid cooler. The FL5 TCR brochure you provided shows one too, but we can't see it in the engine bay picture. I don't know where it is mounted.

The FK2 didn't have a transmission fluid cooler like our cars have. Honda fixed it on the FK8 with a MTF to engine coolant heat exchanger. JAS uses an independent MTF to air cooler instead. This is where the coolant lines to the MTF cooler are connected in our cars:

 

[tezzasaurusrex]

Could the reason for the smaller rear brakes in the rear be for getting more rotation and get some oversteer under braking because these cars are still FWD? Seems like that would make sense since having larger wheels up front and smaller wheels in the rear does make a FWD car more oversteer prone.

I think its done purely for weight saving - its unsprung mass too which in racing and motorsport is extremely important. They must have calculated with the weight distribution of the chassis and brake bias levels they run that the rear's are not doing enough work to require the thermal capacity of large discs. I don't believe it has been done to increase rotation as if that was the premise you would want greater rear brake bias (achieved by increase rotor diameter or caliper piston diameter).

 

[tezzasaurusrex]

Just watched his video, thanks. Considering what happened, that's not so bad. Bad turbo installation (assuming that is what happened, since AN fittings are supposed to be super reliable) could have resulted in fire. It still makes a grown man cry though.

Honestly, I believe he's rushing things. The fact there are many parts from the FK8 readily available probably made him want moaaar before it was wise to do so.

Admittedly I've been giving Gridzila a hard time on youtube with some stern comments on his approach to the whole thing. It somewhat triggered me as the click baity title ("Overheat is alive and well") in his first video on track (when it first overheated) failed to address the root cause and seemed to alude to failure of the vehicle itself which we later found was not true. It all came down to a failed AN fitting or IMO more likely an installation error - if AN lines aren't routed in certain ways the vibration of the engine WILL cause it to loosen up. Its important that these things are tightened, marked, and rechecked and also lockwired, and I suspect none of which were carried out. The second video seemed to place some level of blame on the RV6 turbo which is erroneous as any turbo that continues to be run without a coolant feed will overheat and fail..
On the other side of the coin, we can use his videos as a 'what not to do' lesson for ourselves.

 

[keller]

Admittedly I've been giving Gridzila a hard time on youtube with some stern comments on his approach to the whole thing. It somewhat triggered me as the click baity title ("Overheat is alive and well") in his first video on track (when it first overheated) failed to address the route cause and seemed to alude to failure of the vehicle itself which we later found was not true. It all came down to a failed AN fitting or IMO more likely an installation error - if AN lines aren't routed in certain ways the vibration of the engine WILL cause it to loosen up. Its important that these things are tightened, marked, and rechecked and also lockwired, and I suspect none of which were carried out. The second video seemed to place some level of blame on the RV6 turbo which is erroneous as any turbo that continues to be run without a coolant feed will overheat and fail..
On the other side of the coin, we can use his videos as a 'what not to do' lesson for ourselves.

It feels to me like he wants to jump right back to the point he left his FK8. He did so many changes at the same time without proper testing, or even an inspection after a few shakedown laps. It's ironic that the coolant AN fitting is being blamed (actually the supposedly lack of proper installation instructions). That fitting is one of the selling points of this specific turbo, as the other drop in turbos have coolant lines secured by hose clamps.

Anyway, even though he seems to be quickly jumping to conclusions, it's nice he's willing to test such mods and share his findings publicly. Most of the good information unfortunately is kept in closed circles. It happened with the FK8, it should be happening with the FL5 too.

Now, what is interesting is how you can drive your FL5 to the limit and not overheat it. I saw your onboard videos the other day, you're quite fast. Can you share what you have observed?

Btw, I believe your signature is missing a few letters.

 

[tezzasaurusrex]

Now, what is interesting is how you can drive your FL5 to the limit and not overheat it. I saw your onboard videos the other day, you're quite fast. Can you share what you have observed?

Its been cold here on the Australian south east coast. The hottest being around 22°C (~70F) when my car was last on track - the hottest coolant and oil temps i've logged have been 93°C and ~122°C respectively.
I only tend to do around 2 hot laps per stint as the RE71RS's start to fade, at which point I usually just pull off the track and wait for the next session. It will be interesting to see how things go in the upcoming hotter months. I can tell you there's basically myself and one other guy pushing our FL5's to the limit in Australia. Both of us quickly saw the short comings of the OEM suspension - while most others didn't find a problem with it. Most others are probably driving at 8/10th's, so if anyone was to overheat the car it would be myself.

Btw, I believe your signature is missing a few letters.

Thanks for pointing that out! Fixed.

 

[keller]

Its been cold here on the Australian south east coast. The hottest being around 22°C (~70F) when my car was last on track - the hottest coolant and oil temps i've logged have been 93°C and ~122°C respectively.
I only tend to do around 2 hot laps per stint as the RE71RS's start to fade, at which point I usually just pull off the track and wait for the next session. It will be interesting to see how things go in the upcoming hotter months. I can tell you there's basically myself and one other guy pushing our FL5's to the limit in Australia. Both of us quickly saw the short comings of the OEM suspension - while most others didn't find a problem with it. Most others are probably driving at 8/10th's, so if anyone was to overheat the car it would be myself.

Thanks for this. It seems ECT is well under control. 93°C ECT is the temperature I wait to be at to start a hot lap haha. Have you considered using racing slicks to deal with the heat? Do you think you could push your car for a full 20 min session if not for the tires? People usually say they are not overheating when they can push the car for a full session without a cooldown lap or pulling power. They'll complain and (try to) mod the car until that happens.

Do you usually track your car during the summer? Please report back when you get to warmer weather.

I'd love to read your observations about the suspension. I once saw a video of you seemingly hitting a curb with the inside wheel and the car jumping badly.

@GreenMachineGTE, I think you'll be pleased to read this report.

 

[keller]

Admittedly I've been giving Gridzila a hard time on youtube with some stern comments on his approach to the whole thing. It somewhat triggered me as the click baity title ("Overheat is alive and well") in his first video on track (when it first overheated) failed to address the route cause and seemed to alude to failure of the vehicle itself which we later found was not true. It all came down to a failed AN fitting or IMO more likely an installation error - if AN lines aren't routed in certain ways the vibration of the engine WILL cause it to loosen up. Its important that these things are tightened, marked, and rechecked and also lockwired, and I suspect none of which were carried out. The second video seemed to place some level of blame on the RV6 turbo which is erroneous as any turbo that continues to be run without a coolant feed will overheat and fail..
On the other side of the coin, we can use his videos as a 'what not to do' lesson for ourselves.

RV6 commented about the issue.

https://www.civicx.com/forum/threads/rv6-r660-red-ball-bearing-turbocharger.78137/post-1263615

 

[PointByPatrol]

Thanks for this. It seems ECT is well under control. 93°C ECT is the temperature I wait to be at to start a hot lap haha. Have you considered using racing slicks to deal with the heat? Do you think you could push your car for a full 20 min session if not for the tires? People usually say they are not overheating when they can push the car for a full session without a cooldown lap or pulling power. They'll complain and (try to) mod the car until that happens.

Do you usually track your car during the summer? Please report back when you get to warmer weather.

I'd love to read your observations about the suspension. I once saw a video of you seemingly hitting a curb with the inside wheel and the car jumping badly.

@GreenMachineGTE, I think you'll be pleased to read this report.

Like Osiris from Tropic Thunder...."I don't break character until the DVD commentary!" I'm not the type that wants to back down on track at all, not even for one lap. RE71R's may not be an ideal tire for the track he is accustomed to running. Sounds like a track with HEAVY braking. I don't usually get greasy until lap 6-7 at VIR at +85 degrees F. You've seen my videos...I beat the shit out of that FK8! The ECT's do sound promising, but I never overworked the FK8 at 70F. Only started running into issues at 80+.

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