My S204

Min

Type RA Member
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Hello all, I thought I would do an intro regarding my S204 270/600
I have bought the car completely stock. To this day cannot determine whether it was the right thing to mod a limited edition car, but I am happy with the results. I daily this except for the winter seasons where it is stored in a shed until the snow melts.
The build was really to see if I could maximize the performance without sacrificing daily comfort.
I was thinking of Carbon roof and Endless 6 pot, Ohlins DFV HAL this year but since I just bought an RA-R, I am contemplating what to do next.

First, I will drive my S204 and Ra-r back to back to decide what I prefer and sell and keep one. I am also restoring a FD3s efiny and space is quite limited here.


Suspension
SPOON Rigid collars front and back
Superpro urethane bushes
CUSCO reinforced rubber engine and transmission mounts
Laile front subframe bush
Superpro Anti lift kit
Whiteline stabilizers 24mm front and back
Pleasure racing service alloy endlinks
S204 bbs wheels. 7.4kg Lightest wheel I can find for that size
HankookRs-4 245/40/18
Endless mx72plus pads
Project Mu SCR rotors
Cusco MCS
Stock s204 struts

Engine/other
Tomei 92.5φPistons・HRods・bearings kept it at 2.1 without stroking to 2.2 to keep high rev limit
honed block, WPC processed balanced s204 crankshaft light porting
Clearance and balance checked
Getadomtune reverse cooling mod
KILLERB oil pan and baffle set
HKS Actuator
APP Teflon brake and clutch lines
WALBORO 255L
AUTOSTAFF fuel reg
modified fuel lines from ー1→3→2→4→return, To1→3→return・2→4return。
Trust 52mm radiator
HPI silicon hose
CUSCOpitching arm
HPI 150cell front pipe
Trust full titanium muffler and center pipe
EXEDY VF HYPER SINGLE 5.4kg fly wheel and reduced disc size
Spec c oil cooler
Mature dry carbon rear difuser


Please let me know if you have any questions.
 

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johnfelstead

Type RA Member
If you want to keep the value, keep them stock. Certainly don't install a carbon roof, i would run a mile from anything with a none factory carbon roof installed.

A 2.1 needs a 2.5 crank with 92.5mm pistons (2123cc). If you retain the 2.0 crank it's not a 2.1, just an overbored 2.0 (2016cc).

To get a 2.2 you need a genuine 2.2 block, you could use a short stroke conversion with 2.5 bore size to give you a 2.3 (2332cc).

Don't do the cooling mod, the OEM design is the way it is for a reason.

What sort of power are you looking for?
 

Min

Type RA Member
If you want to keep the value, keep them stock. Certainly don't install a carbon roof, i would run a mile from anything with a none factory carbon roof installed.

A 2.1 needs a 2.5 crank with 92.5mm pistons (2123cc). If you retain the 2.0 crank it's not a 2.1, just an overbored 2.0 (2016cc).

To get a 2.2 you need a genuine 2.2 block, you could use a short stroke conversion with 2.5 bore size to give you a 2.3 (2332cc).

Don't do the cooling mod, the OEM design is the way it is for a reason.

What sort of power are you looking for?
Thanks John!
Thats probably going to be the plan with the Ra-r. Keep it stock with some good brake pads and suspension setup.
Great info on the bore size. My knowledge is quite limited in the modification world so I thought a bigger piston means a stroker. But from what you said and connecting the dots, it makes complete sense now.

In Japan, we have 38deg-41deg (Celsius) quite often in summer, and my car overheats just trying to go up the mountains to enter gunsai touge. This cooling mod felt quite effective as I no longer have temperature issues but would be good to know what your thoughts. I will study abit more around the oem design and why/what this mod can jeopardize it.

I have not done a dyno run but I dont plan to increase other than what I have done now.
I believe the factory boost was 1.5bar, I am running with 1.62bar with EVC 6 2.4IR
A rough guess would be around 340-350hp at the crank.

The goal is to be able to put its pace through anywhere at any temp with minimal burden on the engine. Current setup allows me to run my local circuit (tokachi int speedway) clubman course which is about 2km for about 5 hot laps before the brakes or tyres start to give.
 

johnfelstead

Type RA Member
Thanks John!
Thats probably going to be the plan with the Ra-r. Keep it stock with some good brake pads and suspension setup.
Great info on the bore size. My knowledge is quite limited in the modification world so I thought a bigger piston means a stroker. But from what you said and connecting the dots, it makes complete sense now.

In Japan, we have 38deg-41deg (Celsius) quite often in summer, and my car overheats just trying to go up the mountains to enter gunsai touge. This cooling mod felt quite effective as I no longer have temperature issues but would be good to know what your thoughts. I will study abit more around the oem design and why/what this mod can jeopardize it.

I have not done a dyno run but I dont plan to increase other than what I have done now.
I believe the factory boost was 1.5bar, I am running with 1.62bar with EVC 6 2.4IR
A rough guess would be around 340-350hp at the crank.

The goal is to be able to put its pace through anywhere at any temp with minimal burden on the engine. Current setup allows me to run my local circuit (tokachi int speedway) clubman course which is about 2km for about 5 hot laps before the brakes or tyres start to give.
The cooling mod is lying to you, what it does is remove some flow from the crosspipe where the temperature sensor is located, so it reads cooler and takes heat away from that area designed to be hot (they put the temp sensor there for a reason). Subaru spent a fortune designing the cooling system and how the water flows around the engine to remove heat from where it needs to be removed, as soon as you mess with that you change the efficiency, so you need to think more deeply about what is going on.

The basic fundamentals of this are that you need to be able to transfer the heat generated in the engine away from it into the surrounding airflow, so when you have a situation where the cooling system is unable to do a good enough job of that, the whole assembly starts to heat soak until you hit the limit of what is acceptable, you then have to reduce heat input to enable the system to recover.

In your conditions you don't have a lot of power, so in low ambients its likely to cope, but as soon as you introduce a saturated high temperature ambient air, probably with some altitude also, your efficiency of heat transfer falls of a cliff and you get a rapid buildup of bulk temperature and heat soak becomes a big issue.

The only way out of this is increase the efficiency of the cooling system, that usually requires a larger surface area for the coolers or a more efficient core material within that available surface area, oil cooling makes a huge difference on Subaru's when driven hard for prolonged periods.

If you aren't monitoring it, you need to establish what your oil temperature is doing, if you are seeing over 100 degrees C, your oil cooler is too small. Once you have tackled that and you still have too high a water temperature, you need to change your radiator to one that can handle the conditions.

If the system is correctly sized, you should be able to run the car at full power forever without any temperature issues.

On my car due to the use and increase of power (i have over 500lbft at 3750rpm) i installed a combined oil cooler and radiator assembly that can cope with the extra heat generated, i can run that flat out on track forever. Based on your conditions i would install the race version of this, that will fix your issues.

We are lucky in the UK because our ambient temperatures and humidity help us enormously, we can get away with using the stock systems more easily, but even here once you start pushing hard you hit the same problems eventually.

The engine tune also plays a role in this, you can have limited power increases but if the tune is on the lean side, you generate a lot of heat in the cylinder that the cooling system has to manage. The other thing is driving style, if you drop your shift point by 500rpm you can knock 10 degrees C off your peak oil temperature when your oil cooling is undersized.

On the brakes, there isn't a great deal you can do about them giving up when you run stock calipers (4 pot Brembo), they heat soak badly and then you lose the pedal. Obviously increasing airflow to the caliper body and the disk and using a high temperature brake fluid will help, but often the only answer for a proper track setup is install some more suitable brakes. Tyres again have to match the conditions.
 

SUBGT

V-Limited Member
I can understand that the reading being lower isn't representating the fact that it cools better, because the same amount of heat will raise the temp by the same amount, but how about the fact that it equalizes a bit the egt's on the 4 cylinders?
I am aware that it doesn't help the overall cooling capabilities but having the 4 cylinders at the same temp isn't a bad thing?
 

johnfelstead

Type RA Member
That would depend on what you are actually doing. If the heat output is the same, are you reducing the efficiency of the good cylinder to match the bad one closer? You haven't changed the overall efficiency, it's likely you made matters worse because the manufacturer does a lot of work to ensure hot spots are removed from the areas they develop.

EGT's are a result of the cylinder burn, Subaru's don't have an equal burn rate in each cylinder so you see different EGT's (this is normal for many engines), which is why when you tune them to a high level you use a cylinder offset on the fuel and ignition to balance out that issue.
 

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