Alan Cesar
Alan Cesar SuperDork
3/11/22 12:02 p.m.

[Editor's Note: This article originally appeared in the December 2012 issue of Grassroots Motorsports.]

Tuners and race shops alike are flocking to the new Scion FR-S and Subaru BRZ twins. There’s no doubt this chassis is popular. Shops are scrambling to develop show-and-go parts, but it’s early in the game. No one yet knows the driveline’s weak points or the …

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GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
3/11/22 12:46 p.m.

The first things this car needs are basically survivability mods to address the factory weak points, these are:

- Aftermarket high-flow oil pickup: The stock pickup is restrictive and causes cavitation at high RPMs which is about half the reason these engines have made a reputation for spontaneously lunching themselves. Killer B makes a high-flow pickup. The AVCS synchronization between the two heads will also improve with this mod.

- Oil pan baffle: It's a boxer engine with a plain-jane oil pan so oil has easy access to places it shouldn't go, goes there very easily, and can stay there for a while, this is the other big cause of these engines destroying themselves. An oil pan baffle will fix that. Plenty of options are out there, I went with one from Cosworth.

- Oil cooler: Now that your engine has a good reliable supply of oil, the next issue is that it's going to get that oil roasting hot in anything more than autocross use, even while coolant temps stay nice and stable. You might also want to bump viscosity to 5W30 and of course switch to a synthetic street-performance oil.

- Trans & diff fluid: The factory fluid is not good and needs to be changed quickly, Motul 300 is a good option.

- Temperature-proofing the left inner CV: The exhaust runs right next to this CV, cooking the factory grease until it separates into a runny liquid and some crusty residue. This is what has given these axles a reputation for poor reliability when lowered - it's the decrease in underbody airflow causing the problem rather than the axle angles as some have suspected. Add some insulation/heat shielding to the exhaust where it passes by this joint, and repack the joint with Redline CV-2 high-temp grease. Cusco also makes a heat shield that bolts to the diff here.

- Fixing the fuel starvation issue: The Toyobaru tank can fuel-starve very easily in left-hand turns and increasing fuel flow will only make it worse. Verus makes a drop-in trapdoor for the fuel pump basket that will keep fuel from leaving the basket so quickly. For further improvement you may want to add a second pump to the non-pump side of the tank that will force more fuel into the fuel basket at all times - Phil has done this with his FRS but hasn't given any details, I've been thinking about emailing him to see if he'd spill the beans on this in just the last few days actually.

- High temp brake setup: Standard track-use stuff, you will need high-temp fluid and pads of course, the car doesn't come with them...

Regarding the sway bar issue, this car can definitely use more front anti-roll bias than stock but you may want to consider switching to a much stiffer front bar rather than disconnecting the rear to achieve this, especially if you're on stock-ish suspension (which isn't bad with a lot of front negative camber added).

A performance exhaust and tune fixes the infamous power dip, when you're re-tuning the ECU you should look into altering the radiator fan control tables to get them to switch on at lower temperatures, in stock form the fans are used very conservatively and the engine can even get too toasty in the pits/traffic because of this.

BoxheadTim
BoxheadTim GRM+ Memberand MegaDork
3/11/22 1:25 p.m.

Heh, the list of engine mods reads mostly like the mod list we put on the replacement engine on my BRZ.

One slight correction - the torque dip "fix" is a header plus a tune. Changing out the rest of the exhaust doesn't make much if any difference to the torque dip.

z31maniac
z31maniac MegaDork
3/11/22 1:51 p.m.

This article is 10 years old and there is a lot more knowledge of the platform at this point.

Appleseed
Appleseed MegaDork
3/11/22 2:13 p.m.

In reply to z31maniac :

Any suggestions on more current info? Forums can be filled with bad info that gets repeated.

Colin Wood
Colin Wood Associate Editor
3/11/22 2:14 p.m.

In reply to GameboyRMH :

Thank you for the additional information. I'm sure it will help out quite a few people.

z31maniac
z31maniac MegaDork
3/11/22 2:45 p.m.
Appleseed said:

In reply to z31maniac :

Any suggestions on more current info? Forums can be filled with bad info that gets repeated.

Oil cooler, quality fluids in all of the drivetrain. 

All the "starvation" issues mentioned by Gameboy don't really happen until until you're very fast, on R-comps and have at least some aero. Not and/or, all 3. 

Slippery
Slippery GRM+ Memberand UberDork
3/11/22 3:13 p.m.
z31maniac said:
Appleseed said:

In reply to z31maniac :

Any suggestions on more current info? Forums can be filled with bad info that gets repeated.

Oil cooler, quality fluids in all of the drivetrain. 

All the "starvation" issues mentioned by Gameboy don't really happen until until you're very fast, on R-comps and have at least some aero. Not and/or, all 3. 

I was going to point him here:

Freddy McShreddy

Probably the best mod.

QuikMcshifterson
QuikMcshifterson New Reader
3/11/22 4:44 p.m.

In reply to GameboyRMH :

Excellent advice.

VolvoHeretic
VolvoHeretic GRM+ Memberand Reader
3/11/22 11:34 p.m.

I ran into the Pizza Hut delivery driver climbing out of the older version of that Subaru and told him that his little sports car was pretty hot. First time I had ever seen one up close and I asked him about the engine. He said it was nothing special and I asked him why it didn't come with a turbo WRX 4 banger or a 6 cylinder? Same question for this new one.??

z31maniac
z31maniac MegaDork
3/11/22 11:42 p.m.

In reply to VolvoHeretic :

Because it would dramatically increase cost and weight.

VolvoHeretic
VolvoHeretic GRM+ Memberand Reader
3/12/22 1:11 a.m.

In reply to z31maniac :

How strong is the NA engine in the new version for adding a turbo?

z31maniac
z31maniac MegaDork
3/12/22 9:46 a.m.
VolvoHeretic said:

In reply to z31maniac :

How strong is the NA engine in the new version for adding a turbo?

No one knows yet, it's only been available for a few months.

The previous FA20, seemed to be "OK" around 250whp, to the point Edelbrock would give you a 3/36k warranty on their supercharger/your drivetrain, if installed by an ASE mechanic.

But if you want big power on this platform, be prepared to open your checkbook.

A built engine, turbo kit and the all the other supporting mods, for example depending on how much power you want you'll likely need a CD009 swap. That by itself is just over $5k IIRC.

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