K Swap Success: Engine Choice & Race Preparation

In the world of K series engines, there are many different variations. Lets discuss these options and why KPower builds our mounting solutions around the best examples. We will also discuss how we prefer to race prep a K swapped car.

KPower Industries designs and manufactures engine mounting solutions with one core belief: if you’re going to invest the time, money, and energy into building the ultimate car, why settle for a mediocre engine? That’s why our engine mounts are designed specifically for the Honda K24A2 and K20Z3 engines. We also offer mounting solution for the K24Z engine but only for the 1990–2005 Mazda Miata NA/NB.

We always recommend starting with a mostly unmodified longblock and of these three engines, both K24 variants are readily available with warranties from most JDM engine importers. We recommend sourcing your engine only after you have nearly all the swap components in hand, ideally purchasing it just a few days before beginning your swap and ensuring you can take advantage of the warranty from the engine supplier!

Lets take a look at the 3 best K series engines:

K24A2 RBB:

  • Same as Europe/Australia K24A3 RBB and Japan K24A RBB
  • Supported in all KPower engine swap packages
  • Found in 2004-2008 Acura TSX (USDM)
  • 200hp rated, common to make 220-230rwhp with supporting parts
  • 10.5:1 compression
  • 7,200 RPM stock redline, common to rev to 8,000-8,250 with supporting parts
  • VTEC Roller rocker valvetrain on exhaust and intake camshaft
  • 25 degree VTC intake cam gear
  • JDM engines have a market specific water pump housing, alternator, and automatic belt tensioner. We simply recommend converting these to USDM spec from 2004-2008 Acura TSX. We offer the USDM Water Pump Housing and EP3 Idler Pulley on our website.

K24Z3 RB3:

  • Same as Europe/Australia/Japan K24A RB3
  • Only supported for KPower 1990-2005 Mazda Miata (NA NB) Swap Package
  • Found in 2009-2014 Acura TSX (USDM)
  • 201hp rated, common to make 200-210rwhp with supporting parts
  • 11.0:1 compression
  • 7,000 RPM stock redline, common to rev to 7,500-8,000 with supporting parts
  • Roller rocker valvetrain on intake and exhaust camshafts
  • VTEC valvetrain on intake camshaft only
  • Single exit exhaust manifold port
  • 50 degree VTC intake cam gear

K20Z3 RBC:

  • Similar to Europe/Australia/Japan K20Z4 Type R engine
  • Supported in all KPower engine swap packages
  • Found in the 2006-2011 Honda Civic SI (USDM Market)
  • 200hp rated, common to make 200rwhp with supporting parts
  • 8,000RPM stock redline, common to rev to 8,500 with supporting parts
  • 11.0:1 compression
  • VTEC Roller rocker valvetrain on exhaust and intake camshaft
  • 50 degree VTC intake cam gear
  • Short block deck height is .80 inch lower than K24 engines
    • exhaust manifolds lowest point is lower

For all engine swap packages we offer (except the K24Z3 1990–2005 Mazda Miata swap package), our engine mount solutions fit the following blocks:

  • JDM K24A (RBB)
  • K24A2 (RBB)
  • K24A3 (RBB)
  • K24A4
  • K24A8
  • K20Z3
  • K20Z4

They are not compatible with the K20A2, K20Z1, or K24A1 blocks due to incompatible bolt-hole locations on the left side of the block. Please verify that you’ve sourced the correct block before beginning your project.

Balance Shaft vs. Non-Balance Shaft Oil Pumps in Honda K-Series Engines:

Balance shaft oil pumps and non-balance shaft oil pumps are a hot topic in the Honda world. The K20 engines are the smoothest engines, where as the K24s vibrate more due to the long stroke they have. Moreso, engines like the K20Z3 and K24A come equipped with balance shaft oil pumps, which are designed to smooth out harmonics from the rotating assembly.

Most enthusiasts, however, perform the K20 (PRB) oil pump conversion to eliminate the balance shaft assembly. This swap has been proven to free up horsepower, extend usable RPM range, and improve oiling, though it comes at the cost of increased engine vibration. Here are the key differences:

Balance Shaft Oil Pumps

  • Designed for smoothness and daily drivability
  • Ideal from a street car with some track usage
  • They are reliable up to about 8,000 RPM, making them ideal for street cars or occasional track use.

Non-Balance Shaft Oil Pumps

  • More engine vibration
  • Capable of handling much higher RPM, making them the go-to choice for dedicated track builds
  • We also offer ported versions for improved oil flow and additional high-RPM protection.
  • Ideal for track cars revving to 8,000 and above wanting every drop of power they can make.

For turbo K series builds, we really like the K24A RBB engine with the balance shaft oil pump, you'll have plenty of power to overcome the small HP loss from running it.

If you’re attempting to use an unsupported engine with our engine mounting kits, our engine mounts can serve as a starting point, modification will be required to make them work with these less compatible engines.

For customers with unique cars or especially tight engine bays with plumbing constraints (ex: Mazda RX8), it may be best to give us a call before finalizing your setup. In these cases, older K20A cylinder heads (such as the 2002–2006 Acura RSX Type S) may be worth considering. Upper radiator hoses and heater core hoses can quickly become a puzzle, and without careful planning, you could end up with a maintenance nightmare that’s difficult to service. We’re happy to help you determine the most effective way to route your plumbing and keep your build both clean and serviceable.

Race prepping your engine:

Our KPower swap packages offer a practical and cost effective way to K swap your car. Extra steps may be needed to make your K swapped sustain heavy track use. The following steps should be considered from track dedicated K swapped cars.

Drive-by-wire throttle bodies are fantastic. You can dumb down initial tip in sensitivity by electronic changing the pedal to throttle body ratio with simple ECU programming An example being that with the accelerator pedal pressed down 20%, the throttle body opens only 10%. You can also can take advantage of traction control, no lift shifting, and auto throttle blipping with DBW.

The bad thing is they are sensitive to vibration, and excessive movement can lead to premature failure. Always ensure the weight of your intake piping is not hanging on the throttle by without support. Rubber isolating bushings holding the intake tube loosely to the chassis will help a ton.

Our 3D-printed throttle body adapter is the most cost-effective way to complete your build while also providing vibration dampening for the throttle body. When combined with stiffer engine mount bushings, aggressive rumble strips, or the naturally higher vibrations of track use, the Winning Formula vibration-absorbing throttle body adapter is the go-to solution. While this adapter significantly reduces vibration-related stress, we still recommend keeping a spare throttle body on hand for track cars.

On-board ECU MAP sensors are convenient, but if one fails at the track, your day could be over. Ask yourself, would you rather carry a spare ECU, or a far less expensive spare MAP sensor that can be swapped in minutes before your next session? Our solution is to remote-mount an aftermarket MAP sensor to the chassis, using a vibration-absorbing bushing to protect it from harsh conditions. Ensure you position the sensor so the inlet faces down to keep moisture off it, do not forget to use multi-ply or SS wrapped line to deter shrinking of hose from high idle pressure, keep the length under 2-3 ft. Just like the throttle body, carry a spare.

For all of our Haltech and Link Electronic packages, we include the Bosch 2 in 1 oil temp/pressure sensor mounted right to the engine block, which is great for offering a lot of data for a street/mild track car. However, for extreme cases aftermarket oil temperature, oil pressure, and fuel pressure sensors should be remote mounted to the chassis, not on the engine. Often times you will have an oil cooler, so simply mount the pressure and temperature sensor right to the oil cooler with a simple Radium inline fitting. This will sound familiar, carry spare sensors at the track, and do not forget to program your fail safe ECU protections (yes, even your tuner can forget to do this!).

Mounting fuel pressure regulators directly to a fuel rail sure does clean up the install, but just like everything else, you should have this chassis mounted. Radium a very nice combination regulator with a built in fuel damper to smooth out noisy fuel systems. 

It is absolutely critical to run a flexible pipe section after your header. Without it, engine vibration transfers directly into the rest of the exhaust system, causing stress, cracks, and even damage to other components. We recommend Vibrant’s “TurboFlex” section, the most durable option on the market. While it is stiffer than their standard flex, choosing the longest version available provides the greatest vibration absorption.

Keep in mind, a worn-out exhaust system can contribute to vibration as well. Blown-out mufflers or resonators act like amplifiers, turning your exhaust into a tuning fork that sends vibrations straight back into your engine and chassis.

For proper heat management, any car that sees track time should have protection in place for heat-sensitive components such as engine mount bushings, radiator hoses, clutch slave cylinders (Especially 1990-2005 Mazda Miata NA NB), fuse boxes, and wiring. Exhaust systems radiate a tremendous amount of heat, and without shielding, these parts will fail prematurely.

The most effective solution is custom Inconel shielding designed specifically for your exhaust manifold or turbo setup, we recommend companies like HeaderShield for this service. For those on a tighter budget, Inconel sheet can also be used to cover and protect critical components, ensuring reliability under extreme conditions.

We hope this has been helpful! Have questions? Call us at 847-865-5739 and ask for Dustin, or schedule a 15 minute call here.

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