27WON 11th Gen Honda Civic Turbocharger Design & Development

[Vincent@27WON]

The OEM turbocharger is great on the stock Si and 1.5L turbo engines however it is just small and; well I'll be honest I want to make more power sooooo.. Time to make a turbocharger upgrade. Follow along on this thread as we do just that.

Turbocharger Design Blog Pt 1.

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[Vincent@27WON]

going to drop part 2 of our blog here in the next week or two and will take an even deeper dive.

 

[kanav]

Is the plan to work on 1 turbo at first or go straight to having multiple models like W1/W2 for the 10th gen?

Either way excited for the blog post 2!

 

[Vincent@27WON]

Is the plan to work on 1 turbo at first or go straight to having multiple models like W1/W2 for the 10th gen?

Either way excited for the blog post 2!

That is a great question. The focus will be on a Kuro stage 1 first but seeing the suite of parts for the 10 gen if the request and demand is there we can make a stage 2 as well.

 

[Vincent@27WON]

IN PART ONE OF OUR DESIGN BLOG SERIES FOR OUR UPCOMING 11TH GENERATION HONDA CIVIC TURBOCHARGER WE COMPARED THE OUTGOING OE MHI 10TH GEN TURBO TO THE CURRENT IHI 11TH GEN TURBO. WE LOOKED AT SOME OF THE KEY DESIGN FEATURES BETWEEN THE TWO AND COMPARED THE NUMBERS BY LOOKING AT THE WHEEL SIZES SIDE BY SIDE. IN THIS BLOG, WE WANT TO SHARE SOME OF OUR GOALS FOR THIS NEW TURBO UPGRADE AND HOW IT WILL TAKE THE FE1 CIVIC TO THE NEXT LEVEL.

At the root of it, the goal of a larger performance turbo upgrade is to make more power. We want to create a unit that has the ability to both produce and sustain more horsepower and torque than its factory counterpart. We not only want to improve peak numbers but we want to see gains under the whole RPM power band. More about why this matters will come in a later blog. In setting up our design goals we took a fresh look at our W1 10th-gen unit and asked ourselves how we could improve it for the next generation. The W1 was a trendsetter in the 2016-2021 Honda Civic market and was the first true drop-in turbocharger upgrade. It paved the way for a bunch of clones. We learned a lot from the W1. We saw what worked and figured out what we could improve on for the 11th gen.

Before we even get into bigger components let's talk about materials. We want this new turbo to be more robust than anything we have designed to date. Here is how we are doing that.

STARTING WITH THE TURBINE HOUSING WE ARE UPGRADING IT TO A MORE RESILIENT MATERIAL. THE W SERIES OF TURBOCHARGERS USE D5S STEEL FOR THE TURBINE HOUSING. IT’S GOOD METAL AND HAS BEEN USED IN TURBOCHARGER TECHNOLOGY FOR A LONG TIME. IT IS TRIED AND TRUE. THIS MATERIAL EXCELS IN LARGER-FRAME TURBOCHARGERS WITH PORT FUEL INJECTION AND IN APPLICATIONS THAT RUN COOLER. IN OUR TIME WITH THE 10TH GEN, IT HAS BEEN PROVEN THAT THESE LITTLE GDI ENGINES MAKE A LOT OF HEAT FROM A LOT OF BOOSTS. GIVEN THE SMALL FRAME, HIGHER-THAN-NORMAL LEVELS OF HEAT, AND PROXIMITY OF THE WGA EXIT HOLE TO THE BORE, SMALL CRACKS CAN APPEAR EVEN ON OE TURBOS. WHILE THESE ARE NOT DETRIMENTAL TO PERFORMANCE IT'S NOT SOMETHING WE WANT TO SEE. TO KEEP THIS FROM HAPPENING AND TO ELIMINATE ANY POSSIBILITY OF RUST WE WILL BE UTILIZING A PREMIUM GRADE 310 STAINLESS STEEL MATERIAL FOR OUR MANIFOLDS. THIS MATERIAL IS MUCH MORE RESILIENT TO HIGH HEAT AND KEEPS ITS FINISH LONGER. WHILE A MORE EXPENSIVE MATERIAL THAN THE OUTGOING IRON ITS BENEFITS JUSTIFY THE PRICE.

Remember, heat is the killer of everything and your turbine wheel sees a lot of heat so we looked for improvements here as well. The turbine wheel also sees a lot of fuel and detergents so material that can handle the chemicals, as well as the heat, is key. There is no shortage of materials that can be used. Some options are SS 418, Mar 246, Inconel 713, Inconel 718, etc. SS 418 is a good starter material but does not tolerate heat over 1000 deg F very well. Mar 246 can tolerate more heat and chemicals than the SS 418 but production control of the material can be very complicated. We have had great success with Inconel 713 in the W-series lineup but are exploring upgraded variants of this super alloy like Inconel 718. This superalloy is a high-strength nickel-based superalloy used for cryogenic temperatures up to 1200°F. I won’t bore you with the details but rest assured that we will be using the latest in metallurgy for turbine wheel strength.

The compressor wheel will also be getting several updates in technology. The turbo in the 10th gen Civics with the L15 engine used flank milled machining techniques which work well but better technology is available. When we launched our FK8 turbo a few months back we utilized point-milled technology. Flank-milled is a cheaper and easier method of machining. It works well but leaves performance on the table. Flank-milled wheels are generally heavier and don't allow for as complex of a design. Point-milled is a much more precise and expensive way to machine the wheel. By using individual tool paths during machining much more complex designs and geometry can be obtained when creating this type of wheel. This translates into a better flowing wheel. We will be using point-milled wheels on the 11th gen.

 

[Vincent@27WON]

WELCOME TO PART 3 OF OUR 11TH-GEN KURO TURBOCHARGER DESIGN BLOG. IN OUR LAST BLOG (PART 2) WE WENT OVER THE MATERIAL OPTIONS FOR THE NEW TURBO AND WENT INTO DETAIL ABOUT WHY WE SELECTED PARTICULAR METALS FOR THE WHEELS AND HOUSINGS. IN THIS BLOG, WE ARE GOING TO TAKE A MORE IN-DEPTH LOOK AT THE COMPRESSOR AND TURBINE WHEELS AND SHARE WITH YOU THE SIZES WE SELECTED AND WHY.

Before we dive into the wheel sizes let's first take a look at the diagram below to familiarize ourselves with some vocabulary. We have the compressor wheel which is on the intake side of the engine. That is the wheel that compresses the outside ambient air. Then we have the turbine wheel which is on the exhaust side of the turbo and sees the really hot exhaust gasses. Each wheel has what’s known as an inducer side and an exducer side and they direct the flow of gasses in and out of the turbocharger as in the picture below.

Let's first dig into the compressor wheel. The OEM compressor wheel is not a bad piece. It’s made well and looks high quality. It is a billet aluminum piece which is an upgrade from the cast aluminum wheel that was OEM in the 10th gen. It uses a 6x6 blade configuration which means it has 12 blade tips on it; 6 alternating tall ones and short ones. This 6x6 configuration is similar to the setup on the 10th gen OE turbo and to our W1 turbo for the 2016-2021 Civic. It is a good setup and spools very fast because the little blades can start moving air sooner than the big blades can. It's a bit of a compounding effect as the little wheels “get it started” while the big wheels help once the compressor side is already moving. Remember from our last blog that the OE compressor wheel has a 36.3mm inducer and a 47.7mm exducer. In the world of turbochargers, this is pretty small.

Compressor Wheel Selection

Now there are many ways to make power with aftermarket turbochargers, but by far the simplest and most straightforward way is to make this wheel bigger. So that is where we started. Our 11th gen Kuro turbo will likely utilize a 47mm inducer and a 58mm exducer on the compressor wheel. That is a 30% increase in size on the inducer and a 21% increase on the exducer. The logic here is very simple: a bigger blade size means we can move more air to make more power. The next consideration is blade configuration. The more blades you have the more surface area you have for air to spool up the turbo. However more blades mean less physical room for air so you can’t flow as much on the top end. For Kuro, we have opted for an 11-blade setup. The one less blade helps move more air for more power. The wheel is large and the 11-blades are all the same height so there will be a penalty in spool characteristics. If we find the trade-off on top-end power to spool (responsiveness) out of balance, we’ll adjust. To better get the best of both worlds (responsiveness and top-end power) we keep a lightweight billet aluminum design and use point-milled machining so that we can create a profile that improves the spool. We also did some tuning on the exhaust side to improve the spool. More on that later.

Turbine Wheel Selection

On the turbine side, the tiny OEM wheel has 9 blades. This small wheel spools up very fast which is what makes your 11th gen turbo Honda feel a bit like a naturally aspirated car since turbo lag is almost non-existent. But again that trade-off is the tiny turbo really loses steam up top. Basically, after 5000rpm this little engine falls flat on its face. But it's okay because we are fixing that!

LOOKING AT OUR UPCOMING KURO WE UPPED OUR GAME BIG TIME. WE ARE LOOKING AT A 46.5MM INDUCER AND A 41MM EXDUCER ON THE TURBINE SIDE. THAT IS A 10% AND 20% INCREASE RESPECTIVELY. YOU WILL NOTICE THAT THE JUMP IN SIZE IS NOT AS BIG OF A CHANGE AS IT WAS ON THE COMPRESSOR AND THAT IS FOR GOOD REASON. WE DON’T WANT TO MAKE THIS TURBO SUPER LAZY AND SPOOL REALLY SLOW. WE WANT TO GET MORE TOP END WITHOUT TOO BIG A HIT TO THE TORQUE CURVE. WE SWITCHED IT UP FROM AN OE 9-BLADE CONFIGURATION TO AN 11-BLADE. THIS HELPS SPOOL.

After crunching the numbers and determining our goals we feel that this wheel setup has a place in our catalog. We will be sharing the results of recent dyno sessions and tuning here so you can see what kind of power we make.

Lastly! We have a question for you and we need your feedback. The total of the turbo switch from the 10th gen to the 11th gen was that Honda used a turbo that spools quicker. That responsiveness feels great at initial acceleration then loses steam. This classic trade-off is larger on the 11th gen than it was on the 10th. What is the perfect first turbo upgrade for your Civic? Should it be pretty responsive and give up some power up top, or would you prefer more turbo lag and a bigger boost in top-end power?

 

[DYI01]

I think the first turbo upgrade should be the quicker spooling option vs. a lazier one. I like the idea of a 310-330whp, 300wtq capable turbo (on pump 93) that hits peak TQ around 700 rpm later than the OEM turbo. It should keep the OEM rods happy, there's no need for fuel system upgrade, and will pull nicely up top. For example something 1/3 the way between the 10th gen W1 and W2.

It's going to be a while before 11th gen owners will have rod options that will support big power.

 

[Vincent@27WON]

I think the first turbo upgrade should be the quicker spooling option vs. a lazier one. I like the idea of a 310-330whp, 300wtq capable turbo (on pump 93) that hits peak TQ around 700 rpm later than the OEM turbo. It should keep the OEM rods happy, there's no need for fuel system upgrade, and will pull nicely up top. For example something 1/3 the way between the 10th gen W1 and W2.

It's going to be a while before 11th gen owners will have rod options that will support big power.

Going to be tricky to see 330 whp on 93 oct alone. You will most certainly need ethanol to make that kind of sauce.

 

[Vlad@27WON]

NEWS NEWS NEWS! 329 WHP/323 WTQ. We achieved gains of 140WHP and 131WTQ over stock with some good ole Ethanol!!

Feel The Power

Our next step is setting up an early access list for our pending release. If you’re ready for some more power for your 1.5T powered Si, EX, or Touring, drop an email to [email protected] and let us know some details about your build and goals.

 

[torquestable]

Hi, I just got my 23' Si a week ago. Very excited to find out, theres more power available with this development. Can you tell me what the power would be ( rough estimate ) on 93 octane ? Same car you have but no ethanol.

 

[dastanli]

NEWS NEWS NEWS! 329 WHP/323 WTQ. We achieved gains of 140WHP and 131WTQ over stock with some good ole Ethanol!!

Feel The Power

Our next step is setting up an early access list for our pending release. If you’re ready for some more power for your 1.5T powered Si, EX, or Touring, drop an email to [email protected] and let us know some details about your build and goals.

Is there any artificial drop in torque from 2000rpm to 3250rpm done on purpose to protect the trans or is that just the lag from it being a bigger turbo?

 

[dastanli]

I'd be happy with quick spool and a flat torque curve of 230ish lbft of torque all the way to redline.

 

[Vlad@27WON]

Hi, I just got my 23' Si a week ago. Very excited to find out, theres more power available with this development. Can you tell me what the power would be ( rough estimate ) on 93 octane ? Same car you have but no ethanol.

You'd be looking somewhere right in the 300WHP range assuming you've got solid supporting mods.

 

[Vlad@27WON]

Is there any artificial drop in torque from 2000rpm to 3250rpm done on purpose to protect the trans or is that just the lag from it being a bigger turbo?

Larger turbine wheels simply require more effort to move so that's why you can see power building further in the RPM band. With larger turbo's it's often a balancing act in terms of down low spool vs mid and top end power.

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