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How to Performance Mod Your Subaru WRX STI Without Blowing Anything Up

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My 2019 Subaru STI Limited

My 2019 Subaru STI Limited

Maintenance, Maintenance, Maintenance!

Why spend hundreds and even thousands of dollars to modify an already-working car, but cheap out on the basics? I don't know, but people do it all the time.

Get More Oil Changes: The Subaru manual says every 6,000 miles. Yeah. That's for a stock Subaru. That's not for your new speedbeast. You are pushing your car to the limit. Even with fresh new parts, your engine still has a lot more work to do now.

Use Better Fuel: You wouldn't feed Usain Bolt a diet of Pop Tarts and Mountain Dew. If you can swing it, go to an alcohol-injection system and use the E85 fuel. If you can't, or haven't yet, use premium gas. A Turbo engine like the Boxter will perform better with the higher octane.

Don't Drive it Cold: Yeah, you're gonna have to waste some of that precious premium gas and let the car warm up before you drive it. Do most cars need to warm up? No. But if you are modding your car and making it do things the manufacturer never planned for? Yeah, you should.

Clean the Car Regularly: Sorry to say but my Subi is not a garage queen. So until I get my laser-guided bird defense system up and running, I gotta wash this thing once a week, and do frequent spot checks to make sure they haven't dookied any landmines on my paint.

How to Craft Your Masterpiece

A lot of people go into this thinking ooh, this looks cool, let's add it! That looks cool. Add that!

I did that with my old car, an Audi A3. I did everything wrong. Got an extended warranty. Then did a bunch of mods that all but voided the warranty (more on that below). Then got big tires because I don't know, I'm an idiot. Then sold the car for a huge loss.

I swore with this new car, I wouldn't do that. I would research, plan, and then execute, after I had a complete picture in my mind of what I wanted the car to be.

Do you want to race? Take it to car shows? Drive through the mountains of Bolivia? Look cool in the parking lot? Blast people's windows out with your loud-ass exhaust? What are you DOING with this car?

Before doing any non-cosmetic mods, you need to have an engine management system. Cars nowadays are really just computers on wheels. If you add or change a part on a car but the car doesn't know that you've changed it, your car will drive around thinking the old part is still there. People who change their intake without an engine management system end up with shitty gas mileage, because the car doesn't know what to do so it just wastes a bunch of fuel.

After you have an engine management system, you can then, if you want, change to an alcohol injection system--in other words, you can use E85 gas. This may give you enough of a performance boost that some other mods will be unnecessary. It makes the car run cooler and prevents knocking.

ICT Billet Ethanol Flex Fuel Sensor

Is Getting a Flex Fuel Sensor Worth It?

What Next?

After you get an engine management system and maybe an alcohol injection system, you can then install a better intake, or a turbo-back exhaust. However, you will also need an oil catch can, or an air oil separator (AOS) because the stock part won't be able to handle what you're throwing at it. This non-glamorous mod is often overlooked, but is essential to keeping the car running smoothly.

Why on earth would I cover up these beauties?

Why on earth would I cover up these beauties?

Mods To Skip

If you're modding your car for looks...fine. I can't tell you what will make your car look better. Looks are subjective. What I can tell you is what mods will make your car perform worse than stock.

Bigger Wheels: The 2019 STI comes with awesome wheels. They are plenty big, 19", they look great, I like how you can see the performance brakes...there is like, no reason to change them. But if you do change them, dude, do NOT go bigger. 19" is plenty. Forget about cost. Think performance. Big wheels do not equal speed, they don't equal handling, they don't equal precision. They may look cool, but they don't improve the car and may even ruin your car's handling. The car I owned before this one, an Audi, I had a fit of temporary insanity and traded the stock 18's for 20's and boy that was a mistake. I could never get the car adjusted so it rode as good as it rode before. $3k right there down the drain.

Any Mod With Cheap Parts: Why mod the car with worse parts than stock? Modding the car is a luxury. It's not a necessity. If you can't afford it, save up until you can. Don't replace a perfectly good stock part with a sub-par after-market part.

Some small mods, no mapping required: air oil separator, 4 cylinder cooling mod, radiator upgrade

Some small mods, no mapping required: air oil separator, 4 cylinder cooling mod, radiator upgrade

Short shifter

Short shifter

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Jo Gavilan