W1, W2, or W3…How to Pick the Right Sized Turbo for Your 10th Gen Civic 1.5
Ok, here we go. Deep breath. This topic is going to get a bit into the weeds but we promise once you finish reading this blog you will know more about turbocharging your 10th Gen Civic than most other guys and gals. Yup, you’ll score some knowledge and also get to flex in your forums and Facebook groups.
Tl;dr CVT owner? Stick with the W1 turbo. 6 speed owner? For the majority of owners with an Si Civic or a manual transmission such as those found on the FK7 hatch your choice will be W1 or W2. Now, say you want to just have a ripper and blast well into 400 WHP territory then it’s time to consider a W3.
You can’t start talking about the 27WON brand without talking about the W1 drop in turbocharger. This is where it all began. This was the platform's first drop-in turbo. We were numero uno, #1 to enter the game. When the L15 engine first debuted, it was an entirely new engine family. Smaller than its predecessors at 1.5 liters but now employing a tiny MHI turbocharger this was literally a breath of fresh air in the Honda game.
Soon after introduction, owners started craving more and more power. The stock turbo was simply not up to the task.
So, what did we do? We started designing a larger drop-in turbo from scratch that would replace the stock unit with just a simple swap and provided the extra power customers were now craving. What were the essentials of this design? Turbine and compressor wheels that were ~60% larger than stock so the turbocharger flowed more air. A beefier CHRA(Center Housing Rotating Assembly) for strength and more coolant capacity. Finally, we topped everything off with a good dose of new install hardware & gaskets so you’d get everything all in one package without any trip to the auto store mid install. And what resulted from all this? A CivicX turbo upgrade capable of producing upwards of 325WHP on Ethanol with full supporting mods.
Fast forward a couple of years and owners were now building up their engine internals, upgrading their fuel system components, and even running meth injection. The need for an even bigger turbo immediately became clear. Designing a turbo is a balancing act. Go too small and you leave power on the table but go too big and you have a mismatched turbo that won’t feel great on the street.
For the W2 we took the W1 architecture and increased the A/R of the turbo. What the heck does this mean?
We made the compressor and turbo housings bigger! Why? Because now the turbochargers flow capacity is once again increased and can be used to build more boost and flow even more air. The W2 kept the same (large) turbine wheels from the W1 and now paired it with equally large housings. To back up all that increased potential we again strengthened the CHRA with an even bigger shaft and bearing system. The net result? A turbo could pump out upwards of 375WHP!
Was that it? Was the W2 the end of the line? Nope! We didn’t stop there. We wouldn’t be able to Redefine without pushing the limits and so that’s what we did when we released the latest 27WON turbo, the W3 late last year.
This turbo is a culmination of everything learned developing turbos over the last half decade combined with a desire from our customers and the community to crack the magic 400 power threshold with a drop in turbo. The W3 is a big turbo capable of ~415WHP and is best suited for racing, drag, and spirited highway driving in Mexico, if you know what we mean. It’s a top end turbo for those who already have a full roster of supporting mods, a beefier fuel system on-board, and upgraded engine internals. This turbo is not for the faint of heart and when the boost kicks in, all 30+PSI of it, you’ll feel it! What makes the W3 so capable? It combines even larger sized compressor wheels(bigger than W1 and W2) with an equally large A/R (i.e. housing) for the maximum amount of flow while keeping a true drop-in package. It gives up some of the low down spool you’ll find in the W1 and W2 for more top end power. Again, this is a very specific turbo for a very specific purpose and not everyone should run a W3.
So, the final question is how do I choose the right turbo for me? Here are a few pointers we can offer to dial in the right sized 27WON turbo for your FC1, FC3, FK7 or any other 1.5T L15 equipped Civic and we listed all the options out below.
Pick a Ball Bearing (BB) unit for a slightly quicker spool and improved reliability. Pick the Journal Bearing (JB) if your budget is a primary consideration. Both BB and JB come with the same awesome lifetime warranty.
CVT owner? Stick with the W1 turbo. Journal or Ball Bearing are both fine to run. If you’ve got the budget, go with the Ball Bearing and you won’t be disappointed.
6 speed owner? For the majority of owners with a 2017- 2021 Si Civic or a manual such as those found on the 2016-2021 FK7 hatch, your choice will be W1 or W2. With the W1, expect a max WHP range of ~325. This is perfect if you want to keep your engine internals stock and want a responsive turbo that’s great on the street and for auto-x or track duty as well. Now, if you’re going to eventually upgrade the engine internals and run a larger fuel system, it might be better to start with the W2. The W2 is happy working a shift on your stock block and when the time comes to ramp up the boost, the W2 will also be happy to play and perform at max boost with your choice of internals. Now, say you have to have a ripper and blast past 400 WHP, pick W3. Just remember, this turbo is not as responsive as the W1 or W2. Upgraded internals, fuel system, head studs, clutch are a must to run the W3.
Hopefully, this clarifies the turbo selection process for you and will help you pick the right turbo. And a final note…tuning is required for each and every turbo. That typically means a Ktuner or Hondata is required along with a map specific to the “W” turbo you pick. W1 turbos will have an available starter map for the Si trim of the Civic, while other trims and all W2/W3 turbos will need custom tuning. You can grab a tune from one of our recommended etune shops, IMW or Phearable or your local Honda tuning shop.
REDEFINE the Aftermarket
-Vlad