Civic Si Performance Upgrades

John_Zombie

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Hey Guys,

So I am looking to start making some more power out of my 2018 si. I just installed an AEM intake which by the way so far is amazing... Should I go for the hondata tune next and downpipe? What do you guys recommend? Really want to try and get 400HP out this bad boy.
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SDAlexander8

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Hey Guys,

So I am looking to start making some more power out of my 2018 si. I just installed an AEM intake which by the way so far is amazing... Should I go for the hondata tune next and downpipe? What do you guys recommend? Really want to try and get 400HP out this bad boy.
400 HP from a 1.5L engine? Lets dial back those expectations a little bit. Unless you are okay with being on the side of the road watching all of your oil evacuate out the big hole in the side of the engine block after throwing a rod. Paying for a tow to the Honda dealership, where you’ll be writing them a check for 6000$ + labor to replace the entire engine. (Many days without your vehicle)

If this is your daily driver, you need this car to be reliable and get you from point A to point B every day, lets take a step back and start with 250HP. Drive it awhile, enjoy the extra power and see what you can do from there.

If this is your fun project vehicle and you’ve got an extra 20 grand in savings dedicated to modding this vehicle... Hell yeah brother, do it for Dale, lets get 500 HP out of this EarthDreams 1.5L beast!

1: First you’ll need a new clutch/flywheel/pressure plate that can hold down and transfer that kind of power without slipping.

2: You’ll need to disassemble your engine and rebuild it with stronger parts. Rods, pistons, head bolts, injectors.

3: you’ll need a built transmission. 4th gear will explode. Bigger axels?

4: Now you can buy all your bolt ons and Ktuner. Big Turbo, Cold air intake, intercooler, exhaust, front pipe/downpipe, flex fuel kit, motor mounts.

5: You think those stock goodyear all seasons wrapped around those boat anchor wheels are going to transfer 400+ HP to the ground without spinning? Lets talk suspension. Wheels, tires, coil-overs, bigger sway bars, strut tower brace, sub-frame brace

6: Those stock brakes aren’t going to last long... big brake kit. Brembos baby. If your rotors aint drilled and slotted, what are you even doing with your life?

7: Insert cosmetic/aero mods here, because everybody has to know that you’re ready to Race at all times
 
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JT Si

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If you want to increase horsepower like that you're going to need a new turbo, period. The best you can get out of the stock turbo is probably around 300-320HP with full bolt ons and flex fuel, but having low end torque levels that are going to be of questionable safety for the engine.

A bigger turbo like the 27Won or PRL kit is going to help you shift your torque higher in the rev range and help you achieve higher horsepower levels more safely.

Even with a bigger turbo you'll need flex fuel to get upwards of 300.

Are you prepared to install a new clutch that can handle more torque?

I would suggest a starting point would be to get a Ktuner from TSP with the TSP stage 1 tune (free with ktuner purchase from them). Then as you add bolt ons you'll increase your power and torque. If you're still not satisfied with TSP stage 1 and bolt ons, either moving up to TSP stage 2 with flex fuel or getting a custom tune to maximize your power and torque with your configuration of bolt ons.

If you're still not happy with that or you just have money to burn, get a turbo.


Remember, every failure is an opportunity to upgrade.
 
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John_Zombie

John_Zombie

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If you want to increase horsepower like that you're going to need a new turbo, period. The best you can get out of the stock turbo is probably around 300-320HP with full bolt ons and flex fuel, but having low end torque levels that are going to be of questionable safety for the engine.

A bigger turbo like the 27Won or PRL kit is going to help you shift your torque higher in the rev range and help you achieve higher horsepower levels more safely.

Even with a bigger turbo you'll need flex fuel to get upwards of 300.

Are you prepared to install a new clutch that can handle more torque?

I would suggest a starting point would be to get a Ktuner from TSP with the TSP stage 1 tune (free with ktuner purchase from them). Then as you add bolt ons you'll increase your power and torque. If you're still not satisfied with TSP stage 1 and bolt ons, either moving up to TSP stage 2 with flex fuel or getting a custom tune to maximize your power and torque with your configuration of bolt ons.

If you're still not happy with that or you just have money to burn, get a turbo.


Remember, every failure is an opportunity to upgrade.

Damn, my dreams seem unrealistic here XD . I guess the realistic route here is trying to get to the 300's
 


SDAlexander8

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Damn, my dreams seem unrealistic here XD . I guess the realistic route here is trying to get to the 300's
You can throw money at this car and get it where you want. But at that point, wouldn’t it just make more sense to get a different car with a V8 for the same price? Then you don’t have to put in all that work.

This is an economy car, built with (mostly) economy car parts. Things are gonna break.
 

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Hey Guys,

So I am looking to start making some more power out of my 2018 si. I just installed an AEM intake which by the way so far is amazing... Should I go for the hondata tune next and downpipe? What do you guys recommend? Really want to try and get 400HP out this bad boy.
400 HP from the 1.5T? Theoretically, you better damn well re-do all the internals to beef things up. Then (as was mentioned earlier), upgrade the clutch, tires and brakes. And finally, I expect you to post that you had a catastrophic failure in my CivicX tuning reliability survey. :cool:

Save all the money you're thinking about throwing into your car and just trade in for an R.
 

fenix-silver

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400 hp in a FWD daily driver sounds like an awful time.
 

arpypat

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400 HP from a 1.5L engine? Lets dial back those expectations a little bit. Unless you are okay with being on the side of the road watching all of your oil evacuate out the big hole in the side of the engine block after throwing a rod. Paying for a tow to the Honda dealership, where you’ll be writing them a check for 6000$ + labor to replace the entire engine. (Many days without your vehicle)

If this is your daily driver, you need this car to be reliable and get you from point A to point B every day, lets take a step back and start with 250HP. Drive it awhile, enjoy the extra power and see what you can do from there.

If this is your fun project vehicle and you’ve got an extra 20 grand in savings dedicated to modding this vehicle... Hell yeah brother, do it for Dale, lets get 500 HP out of this EarthDreams 1.5L beast!

1: First you’ll need a new clutch/flywheel/pressure plate that can hold down and transfer that kind of power without slipping.

2: You’ll need to disassemble your engine and rebuild it with stronger parts. Rods, pistons, crankshaft, injectors

3: you need a beefier front axel so you don't break that

4: Now you can buy all your bolt ons and Ktuner. Big Turbo, Cold air intake, intercooler, exhaust, front pipe/downpipe, flex fuel kit, motor mounts.

5: You think those stock goodyear all seasons wrapped around those boat anchor wheels are going to transfer 400+ HP to the ground without spinning? Lets talk suspension. Wheels, tires, coil-overs, rear sway bar, strut tower brace, sub-frame brace

6: Those stock brakes aren’t going to last long... big brake kit. Brembos baby. If your rotors aint drilled and slotted, what are you even doing with your life?

7: Insert cosmetic/aero mods here, because everybody has to know that you’re ready to Race at all times
Trading it in for a Type R seems easier than all of that :rolleyes:
 

shibles

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I'd save the 400+ hp dreams for a car better equipped from the factory to handle that kind of power. Most popular mods for the Si are CAI, exhaust, fp/dp, tune, intercooler, etc. With those you'll probably see about 55 - 65 whp increase from stock and 75 - 90 lb-ft torque increase. Those are pretty respectable numbers from an economy 1.5T engine. If you still aren't satisfied with straight line power then you could start shedding weight wherever you can, aftermarket wheels, carbon fiber body panels, etc. Or go looking into a big turbo kit.

Just remember that the spirit of the Civic is a nimble car to swing around corners. It was never meant to beat a muscle car in straight line acceleration. Some of the best builds I've seen (imo) are the ones that give a little nudge in all departments to improve the overall capabilities of the car. Just a thought, happy modding!
 


TornadoredGen3

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LOL you guys are too harsh on the fella... The 400hp mark is out of the question on stock bottom end due to reliability. BUT if you can afford $800 Rods and another 300 installation if you can pull the motor your self and just send it to an engine assembly place you have a decent base .
 

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Downpipe/frontpipe, Intercooler, a bigger turbo and ethanol will put you at 330ish whp. That’s pretty close to 400hp and your stock engine MIGHT be able to hold it. Drob(likely the best civic x tuner) tunes a bunch like that on stock blocks. You can find dyno post on his Instagram/Facebook. It would be a lot more efficient and cheaper to build the block first before pushing your luck but the choice is yours. As for your first step I would get a Ktuner or hondata and do a custom tune with drob or javi immediately, during the tuning process you can ask him about reliable power levels. After the custom tune take things slow, get some cosmetic mods, suspension and driveability mods such as short shifter, steering wheel whatever you feel would make your driving experience more enjoyable and slowly shape the car into your personal perfect version of it. That’s how I would do things anyways. Maybe look at some build threads for inspiration either way best of luck and enjoy your build! @John_Zombie
 

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I was looking at a more respectable 300 as well. Lol was going for a one stop shop like 27Won. Their whole page is a check list of go fast for FBO and tune. Drop in turbo, CAI, turbo back exhaust, intercooler and their TIP is looking good...seems like It'll step to those numbers without too much hassle at all.
 


 


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