Honda 1.5T engines are also known as the 1.5 Turbo and L15 VTEC or VTC. The 1.5L inline-4 engine delivers up to 205 horsepower and 192 lb-ft in the Honda Civic Si. It’s solid performance for such a small engine. However, the 1.5T leaves a lot of room on the table for extra power. Turbo designs allow for excellent power gains with a few simple mods. In this guide, we discuss some of the best Honda 1.5T upgrades along with power gains, benefits, cost, and more.
*The L15 Turbo engines span a lot of different engine codes. Our primary focus is on the L15B7 in the Honda Civic and Civic Si. However, much of this info applies to all turbo 1.5L Honda engines, like the CR-V and Accord. Fitment and exact results vary, but these remain excellent mods for those engines too.
L15 1.5 Turbo Background Info
As stated briefly above, many of the mods and general info in this article apply to all Honda L15 1.5 Turbo engines. There are a lot of different engine variants and models that use this engine family. As such, fitment and exact results from each mod can vary. Regardless, the 5 best Honda 1.5T upgrades apply to almost all of these engines.
All of these engines share the same base design and 1.5L displacement. Honda uses so many engine codes, so it can seem a little overwhelming. However, the differences between the engines is pretty minor.
For additional info, check out our Honda 1.5T common engine problems guide.
Honda L15 1.5T Engine Variants
Bear with us as we break down a little bit of basic information about each of the 1.5T engine variants. Skip down to the best Honda 1.5T upgrades section if you’re not interested in this data. There are 11 variants of the L15 turbo engine, but we’ll stick to quickly discussing the most common 1.5T engines.
Anyways, let’s jump in and discuss the L15 turbo engines. We are looking at the basics here like what years and model use each engine, power output, etc. Afterwards, we will dive right into the 5 best bolt-on engine upgrades for the Honda 1.5 Turbo.
L15B7 VTEC Turbo
What cars use the Honda L15B7 1.5 turbo engine? It’s in the following years and models:
- 2016-2021 Honda Civic Turbo
- 2017-2021 Honda Civic Si
- 2019-2021 Honda Vezel
- 2020-present Honda XR-V
The L15B7 offers 174hp and 162 lb-ft with 16.5 pounds of boost in the standard Civic models. For the Civic Si the engine delivers 205hp and 192 lb-ft thanks to running 20.3 psi. It’s important to note the Civic Hatchback does NOT use this engine. Instead, Hatchback models get the L15BA VTC Turbo engine that’s coming up in a moment.
This engine is one of the primary focuses of this article. Another important note is that horsepower gains can actually be better in the base Civic Turbo models. The Si has more power from the factory since it runs higher boost. In other words, the standard Civic engine is just as capable but it has a lower starting point so power gains appear larger.
L15B7 VTC Turbo
VTC engines see the addition of variable timing control on the intake and exhaust. VTEC still remains on the exhaust side, too. This L15B7 VTC engine is in the following:
- 2022+ Honda Civic
It also runs the same 16.5psi peak as the previous VTEC version in 2016-2021 Civics. Power comes in at 180hp and 177 lb-ft. A solid 6 horsepower increase and an even more impressive bump of 15 lb-ft.
L15BA VTC Turbo
Honda L15BA engines are basically the same as the L15B7 in the Civic and Civic Si. However, it uses thinner connecting rods for whatever odd reason. As to why this engine has its own engine code your guess is as good as ours. It’s in the following Honda models:
- 2016-present Honda Civic Hatchback
It offers the same 180hp and 177 lb-ft when equipped with the 6-spd manual. Power remains the same with the CVT transmission, but torque slips to 162 lb-ft.
L15BE VTC Turbo
Next up is the L15BE VTC engine in the CR-V models of the following years:
- 2017-present Honda CR-V
Boost comes in around 18.5psi and the power output is a nice middle ground between the base Civic and Si models. It offers 190hp and 179 lb-ft.
L15BE VTEC Turbo
Last on our list is the L15BE VTEC engine. You can find this Honda 1.5T engine in these models
- 2018-present Honda Accord
With 192hp and 192 lb-ft it’s one of the more powerful variants from the factory. Horsepower is down from the Honda Civic Si, but it offers the same peak torque with similar boost of 20.2psi.
Best Honda 1.5T Upgrades
Alright – that covers most of the basics. As such, it’s time to move onto the best Honda 1.5T upgrades and aftermarket mods. Tons of different options exist, so where do you even start? What 1.5 turbo mods offer the best bang for the buck? These are just a few of the questions we answer in this article.
To start, a few of the best Honda 1.5 turbo engine mods include:
- Downpipe (exhaust)
- WMI / Fueling
Throughout the rest of this article we discuss the above 1.5T upgrades in-depth. They’re among the best basic bolt-on mods to take the 1.5L inline-4 turbo engine to the next level. It’s generally a good starting point before moving onto more serious upgrades like an upgraded turbo.
*Note – any power gains or specific data is based on rough estimates. Actual results can vary depending on many external factors. Some 1.5 turbo mods on this list may also be illegal in some or all states. They’re intended for off-road use only.
1) Honda 1.5 Turbo Tunes & Tuning
Looking for only one mod for your Civic 1.5T? If so, a tune is without question the best starting point. Not only do tunes offer massive horsepower gains, but they’re also the foundation for building more power. A tune is necessary to maximize performance gains from other mods like an intake, downpipe, etc.
Benefits of running a tune on the Honda 1.5 turbo include:
- 20-40+whp gains
- 20-40+wtq gains
- Better fuel economy
- Data-logging and monitoring
There are tons of awesome features and benefits that come along with the right tune. Gains of 20-40 horsepower and torque to the wheels is already impressive enough. With the right tuning and driving you may notice better fuel economy. However, that’s likely not the case if you’re using the new-found power.
Otherwise, some tunes offer data-logging and monitoring capability. It’s nice to see and know what’s going on with the engine. You can easily read and clear codes, and the list could go on.
Best Civic 1.5T Tunes
Normally we like to include a few options, but we can’t bring ourselves to do that here. Burger Motorsports offers their amazing JB4 piggyback tune for the Honda 1.5T engine. They originally started developing tunes in the BMW world just before 2010 when BMW started building turbo engines. We personally run the JB4 on all of our BMW’s with great success.
Piggybacks are a little different than your standard flash tunes. That’s a conversation for a different time, but these tunes offer so much in a simple package. The JB4 is a simple plug & play install and it offers 9 different tuning maps. You can switch from stock, to a mild tune, to complete kill mode in a matter of seconds. No need to stop and re-flash the entire ECU.
They also offer a few maps compatible with 30% E85 blends. We’ll be discussing this later, but E85 mixes offer lots of potential. The features go on and on, so be sure to check out the JB4. For the price it’s tough to find a single better Honda 1.5T upgrade.
Buy Here: Civic/Accord/CR-V 1.5T JB4 Tune
$ Per HP: ~$10-20
2) Honda 1.5T Upgrades – Performance Intake
This list is in no particular order, but an intake is our second favorite mod. No, an intake upgrade isn’t as capable as the other Civic 1.5T upgrades on the list. However, it’s a great mod to combine with a tune since it’s also easy to install and cheap. As you increase power and boost it’s also important to improve air-flow into the engine. That’s where a 1.5 turbo intake system comes into play. Benefits include:
- Similar torque
- Awesome turbo sounds
- Better response / turbo spool
Again, the gains from an intake aren’t overly impressive. It’s still a great upgrade for many reasons, though. Honda Civic 1.5T intake mods free up a lot of awesome turbo and induction sounds. We think it’s really addicting and would recommend an intake for the sounds alone. Intakes can also improve engine response and turbo spool. Just a few extra benefits to what’s already a great mod for the power gains and sounds.
Performance intakes have so many different names. Intake system upgrade, cone intakes, air-box upgrades, cold air intakes, etc. There’s one primary thing to consider in our eyes – open vs closed intakes.
Open vs Closed Intake Upgrades
An open intake does not have an air-box surrounding the air filter. As the name suggests, a closed system retains an air-box to keep the filter covered in a housing. We’re big fans of open intake systems on turbo engines, and refuse to run anything else on our own cars. What about intake temperatures and heat soak, though? Isn’t it going to hurt the Civic 1.5T’s performance if the intake is pulling in warm air?
Fair questions. This can be very true on a naturally aspirated engine or forced induction without an intercooler. However, the Civic 1.5 Turbo engine does use an intercooler. The air is super-heated while traveling thru the turbo where it’s then cooled by the FMIC. Temperatures at the intake have little to no effect on the intercoolers ability to cool the pressurized air.
That said, open intake upgrades have the least restriction. They’ll offer the best air-flow and the best sounds. In our opinion, running an open intake system like this one from BMS is the clear choice. As with the JB4, we run BMS open intakes on all of our BMW engines with great success.
Buy Here: BMS Honda 1.5T Performance Intake System
HP Per $: ~$25-50
3) Civic 1.5L Turbo Downpipe Mods
A downpipe (DP) is likely the second best bolt-on mod from a horsepower and torque perspective. They’re without question one of our favorite mods on any turbo engine. That also applies to the Honda Civic 1.5 Turbo engine. The downpipe bolts directly to the turbo making it the most important piece of the exhaust post-turbo.
Stock Civic downpipes are great for emissions, but hurt performance a lot. The restrictive cat creates a lot of back-pressure, which slows turbo spool and limits max performance. Reducing back-pressure with Honda 1.5T upgraded downpipes offers a lot of benefits:
- Better turbo spool
- Awesome sounds
- Lower EGT’s
- Reducing back-pressure is healthy for engines
It’s a long list. Not only does a downpipe offer significant power and torque gains, but quicker turbo spool is another major upside. This means a lot more low-end torque. You can also feel more of the push back in your seat feeling.
Combine that with a more aggressive exhaust note that isn’t overly intrusive. DP sounds are mostly noticeable with cold starts or heavy throttle inputs. Otherwise, less back-pressure helps reduce temps and is healthy for the engine and turbo overall.
Civic 1.5 Catless vs High-Flow DP
All of these benefits have to come with a serious downside, right? Unfortunately, that is the case with Honda 1.5T upgrades to the downpipe. The goal is to reduce back-pressure as much as possible. Doing so means eliminating the catalytic converter, which is not street legal. Passing emissions can become an issue.
Enter high-flow downpipes. These Civic 1.5 Turbo downpipes retain a high-flowing catalytic converter. They may still be considered illegal, but it’s more likely to pass emissions. Power gains aren’t quite as impressive as with a catless downpipe, and cats are expensive. It’s still an excellent mod, though.
Best L15 1.5T Downpipe Upgrades
Those opting for a catless downpipe need not consider much when it comes to quality. What’s important with a downpipe is that it’s stainless steel for longevity and fitment is good. Otherwise, it’s a simple steel pipe. Point is – don’t worry too much about quality as long as the downpipe is made from rust-free materials and offers quality fitment.
We like the PLM downpipe found here. It’s one of the cheaper options we came across that’s stainless steel and looks to be a quality downpipe and front pipe combo.
$ Per HP: ~25-75
4) Honda 1.5 Turbo FMIC
The intercooler is an extremely important part of any forced induction engine. Turbos run off hot exhaust gases for one. Air also heats up as it’s compressed. Combine the two and the charge air exiting the turbo is HOT. Obviously, that is not good for performance or engine safety. That’s why an intercooler is standard equipment.
The Honda 1.5 Turbo factory FMIC holds up fine on stock boost. Although, it’s quickly overwhelmed when you start adding more power and boost. Benefits of Honda 1.5T upgrades to the front mount intercooler are:
- Cooler IAT’s
- Consistent performance
- Safer for engine
FMIC upgrades aren’t really a big power mod. They might pick up about 5whp on most setups, but more power is possible. However, an intercooler mod goes a long way in ensuring consistent performance. Ever noticed the car feels a bit sluggish after punching it a few times? That’s heat soak at work. It causes the engine to pull timing, boost, and overall power. As such, an FMIC upgrade may prevent the engine from losing 10-20whp.
Reducing IAT’s help the L15 1.5L engine maintain performance even after multiple back-to-back pulls. Cooler air also reduces the chance of engine pre-detonation events, which is a big cause of blown motors. All in all, don’t expect tons of peak performance gains but it’s still a very worthwhile mod.
Best 1.5T FMIC Mods
Civic 1.5 Turbo engines use an air-to-air front mount intercooler. The intercooler is mounted at the front of the vehicle, and outside air passes thru fins to cool the charge air. Volume and surface area are two important aspects of FMIC upgrades. More surface area and volume generally means better cooling capacity.
Tons of great options exist, but we don’t recommend price shopping on FMIC’s. It’s important to find a quality intercooler that maximizes cooling performance. Two Step Performance, PRL Motorsports, and Injen all have some great options.
$ Per HP: ~$50-100+
5) Civic 1.5T Upgrades – Fueling / WMI
Fueling upgrades and water-methanol injection are lengthy topics and 1.5T upgrades. We will definitely address this in an individual post in the future. However, high octane and high-quality fueling is important when increasing performance. E85 blends are a great option, and some tunes like the JB4 allow for 30% E85 mixes with no other mods.
E85 benefits are endless. It helps the engine run cooler internally, reduces the risk of detonation, and has a rating of 108 octane. Power gains can be massive even on small blends of E85. The downside is that E85 is less fuel efficient and puts higher demand on the fuel system.
WMI offers similar benefits, but actually reduces demand on the fuel system. It also lowers intake temps significantly. These mods are a bit more advanced, so we don’t recommend jumping right in on E85 or WMI. Stick with the basic Civic 1.5T upgrades to start, and work up to more serious mods like fueling and water-methanol injection.
Price: E85 is the same price as lower grade fuels. WMI is generally $300-500+ for the full kit.
HP Per $: E85 blends – unlimited ($25-50 for WMI)
Other Honda 1.5 Turbo Mods & Supporting Mods
We already wrote a lot more in this article than originally intended. As such, we’re going to keep things pretty short in this section. Be on the lookout for new content in the near future. We’ll expand on many of these additional mods below in posts of their own. Anyways, a few extra power mods to consider include:
- Turbo upgrades
- Fueling upgrades
You may also want to take into account any supporting mods. More power means more heat. It also means you should consider traction, braking, suspension, and more. The major topic is with the CVT transmissions.
Honda CVT Transmission Mods
Some CVT trans begin running into issues in the 220-240 wtq ballpark. It’s not a perfect science as to when the transmission start having issues with more torque. However, it’s something to consider addressing. There are CVT cooler upgrades that may go a long way in supporting the extra power and torque.
Best Civic 1.5T Upgrades Summary
The Honda Civic 1.5 Turbo offers great performance for its size. It’s also an efficient engine that offers solid reliability. However, some are always looking for more power and performance. The 1.5L inline-4’s turbo design leaves plenty of power on the table. A few simple Honda 1.5T upgrades can take the engine to the next level.
Tuning is usually the best single mod and starting point for the Civic Turbo. It’s the best bang for your buck, and also maximizes power gains from other mods. An intake is a good mod to couple with a tune. If you still want more power it’s time to move onto Civic 1.5T downpipe and FMIC upgrades. Fueling mods offer even more power, but it’s generally something to work your way up to last.
Combine these simple bolt-on mods and the Honda L15 Turbo engines can pick up as much as 50-70whp. That’s really impressive for a small 1.5L engine. One major concern is the CVT trans, so be cautious with torque or consider upgrades for the transmission. Ultimately, mod away and have some fun!
What’s your experience with Honda 1.5T upgrades? Are you considering any?
Leave a comment and let us know!