Insane Shafts 500HP Axles for RSX Base/EP3 Civic Si/EF K Swap

Insane Shafts 500HP Axles (IS-015 / IS-016) - RSX Base, EP3 Civic Si & EF K-Swap

Here's how it usually goes. You get the K-swap running in your EF, or you start adding real power to your RSX Base or EP3, and everything feels great right up until you dump the clutch and hear a bang you can't unhear. Factory axles were never built for what you're asking of them, and they're almost always the first thing to give up once the power goes past stock. Insane Shafts built the IS-015 and IS-016 for exactly this combination, and they're rated to handle up to 500 wheel horsepower whether you're on the street or on track.

Read This Before You Order

These do not fit the RSX Type-S or Type-R. That catches people out constantly, because Type-S owners are usually the ones shopping hardest for stronger axles. This kit is for the RSX Base, the EP3 Civic Si, and EF Civic and CRX chassis running a K-swap. If you're doing the EF swap, you'll need the K20 RSX or EP3 half-shaft to make it work. Sort that out before you buy so you're not sitting on a set of axles you can't install.

What Makes Them Hold Up

The strength comes from two things, and the second one is where most budget axles fall down. First, they're forged from chromoly steel, so you're starting with better material than the factory unit. Second, and this is the part that matters, Insane Shafts runs them through their own annealing and heat treatment process afterward. That relieves the internal stress left in the metal, which is what keeps the shaft from fatiguing after a few hundred hard pulls. Plenty of cheap axles are made from decent steel and then skipped through the process that makes that steel actually last. Torsional load is relentless, and a shaft that hasn't been treated properly will eventually let go no matter what it's forged from.

They Still Have To Drive Nice

A strong axle you hate living with isn't much of a win. The outer joints use 26-spline hubs, which is the correct spec for K-swapped EF chassis and for RSX Base and EP3 cars, and the joints are built to OEM-style tolerances. That's why they run smooth instead of giving you the vibration and clunking that comes with a lot of cheaper aftermarket axles. Both inner and outer CV boots are new and sealed, so you're not fighting a torn boot and slinging grease six months in.

What Shows Up At Your Door

You get a complete left and right pair, IS-015 for the driver side and IS-016 for the passenger side. New spindle nuts come in the box too, which we appreciate, because reusing old hardware on a part at this price point is asking for trouble. Removable ABS rings are included where your application calls for them. There's no core charge and no half-kit nonsense where you order twice to get one car's worth.

Backed For The Long Haul

Insane Shafts covers every axle with an 18-month limited warranty. That tells you something about how they expect these to hold up. This isn't a part you buy to get through the season and replace later. It's the one you put in and stop thinking about while you keep building.

Who This Is For

This is for the person whose build has outgrown its axles, or the one smart enough to handle it before it breaks. Maybe you're finishing an EF K-swap and you want the driveline sorted from day one. Maybe your RSX Base or EP3 is making real power now and you're tired of babying the launch. Either way, get these in, get your half-shaft situation right, and go use the power you built.

Fits: 2002-2006 Acura RSX Base, 2002-2005 Honda Civic Si (EP3), and 1988-1991 Honda Civic and CRX with a K-series swap. Does not fit: RSX Type-S or Type-R. Requires: K20 RSX or EP3 half-shaft. Rating: up to 500 wheel horsepower, street or track. Part numbers: IS-015 driver side, IS-016 passenger side. Construction: forged chromoly steel with proprietary annealing and heat treatment. Splines: 26-spline outer hubs. Includes: complete left and right pair, new inner and outer CV boots, new spindle nuts, removable ABS rings where applicable. Core charge: none. Warranty: 18-month limited.