Getting more whp on the FA20
 

Hey everyone!

I've recently purchased a 2018 Subaru BRZ sport tech. Dont get me wrong but I do love driving this car. I'm not one that cares for 0-60 times or ¼ mile times. I wanted something that was amazing at handling/ carving corners and something I can get into drifting with.

A little extra power would be amazing. I would be completely satisfied with 300whp. I know the stock FA20 block has reliability issues when seeking for more power. Where I live E85 is not something that's readily available so I would stick to pump fuel, 91 or 94.

As far as getting the power I'm still debating between a turbo or supercharger. Just starting my research now but want to get somewhat of idea what things I should be looking at or where to start. Do you think 300whp is attainable on a FA20? What things would need to be done to still have reliability in the motor/ transmission/ drivetrain components? What would I be looking at roughly as far as cost goes for building someone like this?

Thanks everyone in advance for your opinions/ feedback!

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I know there is a forum search button, but yes 300 whp is attainable. It will require forced induction. You'll need a great tune and supporting mods to be as reliable as possible. Expect a pretty decent investment to have a turnkey reliable setup.

300whp is definitely attainable with most FI kits on the market right now with E85, but I know you said E85 isn't really available in your area. Reliability gets thrown out the window when you boost your car, but the chances of your engine blowing up is pretty rare, given that you went with a good tuner.

With that being said, 300whp is pretty high for the FA20 engine. The rods aren't as strong as the one's in the FA20DIT from the WRX. I believe 240-270whp is the sweet spot with this car and it's weight.

Look into the ACE 350 Header with an Ecutek tune. That should net about 20whp safely.

In terms of supporting mod, you'll want an oil cooler, gauges (boost, AFR, oil pressure), gauge pod to hold your gauges, catchcan, an ecutek tune and device. If you include all that with your FI kit, you'll be looking at around $7k-9k with installation. I don't recommend doing this until your powertrain warranty is out.

As for SC or a turbo..that is up for you to decide. Tons of threads out there about this topic. I personally like the SC route for the instant throttle response and boost.

Best SC kits for our car would be the Jackson Racing, Edelbrock and Harrop. Best Turbo would be JDL and Fullblown. This is just what I've gathered from hundreds of hours of research before boosting my car.

I SC'd my car and it all costed me $6k. Good luck.

Awesome good to know it is attainable. I know anything boosted can be prone to issues but I don't want it totally unreliable where I'm going to worry everytime i drive it or push it a bit if the engine will blow. Definitely waiting until my powertrain warranty is up so it gives me a reason to wait and save up the next 5 years or else I would have done it right now if I bought a used one. Lol.

Definitely going to start off with headers and a tune then go from there. That's less than what I was expecting. I was thinking 10k+ but your costs seems alot more attainable. As for your setup is it pretty reliable? Do you daily drive it or more of just a weekend car?

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If you go with a header you'll want to consider a SC as a turbo kit (except for like one or two, can't remember which one) will replace the header with their own header. Go Ecutek and not OpenFlash Tablet since you'll be needing Ecutek when you go FI.

Reliability is great, but I only have 5k miles with the kit. It's a daily driven car, with about 400 miles per week. Like I said, any kit is 'reliable' if you have a great tuner. I recommend Delicious Tuning, Moto-East (now known as Xero-Limit, HRI Tuning, and JRTuned. Those have the most knowledge of our car's engine. I boosted my engine when it had 73k miles, but compression test showed that it's still very healthy.

300whp on pump is really pushing the limits of reliability. Especially on a SC setup.
Obviously more power and boost more, risk lots of people have had different experiences and opinions. But generally
300whp on E85
285whp on pump+wmi
270whp on 93
250whp on 91
Are pretty safe numbers to obtain and maintain good reliability.

The things that generally blow engines are torque, torque hits, and knock.
Having a slower more gradual torque ramp up and not exceeding about 210-230wtq peak (based on fuel) as opposed to a massive hit of torque down low or a sudden spike of torque very quickly in the power band.

I'm really surprised nobody here mentioned a clutch. Also driving habits and luck play into reliability. As someone mentioned before, I know you think it's a novel question, but it really had been asked I'd say maybe half a million times. You're planning on spending 10k on something, research. And bank some money if something goes wrong:)

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Yes a clutch will be 100% necessary. I believe stock clutch starts slipping around 180wtq once clutch is upgraded stock trans should be good to about 240wtq before the gears are at a much higher risk of shearing.

And like you mentioned. 300whp on a daily vs 300whp on a track/autox/drifting are two totally different scenarios. With the later requiring a much more extensive and costly build to try and keep some what reliable.

Can get a bolt on turbo kit for $3k and install your self, about $1k for tune. And probably $1500-$2000 for wheels/tires to put down the power. And about $750 for clutch to hold the power if you install yourself. And you'll have all you really need for a pretty reliable DD at about 250-275whp for about $7k all in. But i would not advise to do anything beyond spirited driving/hwy pulls with this base boosted setup.

My stock clutch has held up fine on the street for the last couple of thousand kilometers.

I run it hard daily.

AVO turbo, 8psi, 270hp.

If you really want to get into drifting I'd start with a header/tune, shorter diff gears (4.5-4.8) and a 2 way LSD. Then I'd take out as much weight as you can stand.

If that's not enough go F1. None will be wasted money except for the tune update.

Seems a tad low for AVO turbo at 8psi. Low octane fuel in your area?
Stock manual transmission is rated at 250nm or 185ft lbs torque.
Sure it can probably work and hold up for a while for some people. Just like some people have gone 5k+ miles at 400whp on stock block and others bend a rod at 500 miles at 200wtq/240whp how its driven and luck play a big role. But I wouldn’t consider the stock clutch to have any long term reliability at 220wtq just my 2 cents.

Without E85, lower compression is the best way for more power. I don’t think the OP is going to do an engine build though. There are some tuning tools to reduce the effective compression ratio, but nothing will beat E85/meth/octane or lowering compression for safety.

Safe fat tune.

Typical numbers for here in Australia on a chassis dyno running 98 ron.

Right, except the gains with E85 aren’t as much with lower compression, depending on the ratio and the amount of boost of course, but often people will hit the limits of their basic engine builds or of the transmission or of the axles before needing E85 on top of lower compression.