PRODUCT DETAILS
Driveshaft Shop X4 700HP Axle Set - 2012-2015 Civic Si & 2013-2015 ILX 2.4 (510358 / 510359)
This is the axle for a fast street car that still shows up at the track. Driveshaft Shop's X4 line is built from 300M with their best heat treat processes, rated to handle 700 to 1000 wheel horsepower depending on application, and it's a direct bolt-in. On a K24Z7 car making real power, this is the tier that stops axles being the weak link.
ILX Owners: 2.4 Manual Only
Check before ordering, since the ILX came two ways.
These fit the 2.4 manual ILX, which runs the same K24Z7 and transmission as the Civic Si. The 2.0 automatic uses a different drivetrain entirely and these won't work with it.
If you're in a Civic Si, every one of those is the 2.4 manual, so there's nothing to check.
300M Is Why It Holds
The material is the reason for the rating, and it's a genuinely different tier from what ordinary axles use.
300M is a high-strength alloy used where failure isn't an acceptable outcome. Combined with Driveshaft Shop's heat treat processes, it's what lets these handle the torque and shock loading that destroys lesser axles on a hard launch.
Axles fail in torsion rather than bending, so material strength through the bar determines whether one survives a sticky tire and a built engine. That's where the 700 to 1000 wheel horsepower range comes from.
Built For Cars That Do Both
Driveshaft Shop engineered the X4 line for fast street cars that visit the track for drag, road course, and autocross duty. That's a demanding category, since the axle sees daily driving loads, launch shock, and sustained cornering load in the same week.
On a 9th gen Si that's usually the profile. These cars get driven, and the ones making real power are typically still someone's actual transportation rather than dedicated race equipment.
Direct Bolt-In
No hub change, no modification, no adapting anything. These go in where your factory axles came out, which keeps the job straightforward and keeps the cost to axles rather than an entire package.
Non-Refundable After Installation
Once installed these can't be returned, which is standard for driveline components at this level. Confirm your application before ordering rather than after.
Check Your Range Of Motion After Install
Once fitted, cycle the suspension through full travel and turn to full lock both directions. You're checking that the inner joint isn't bottoming out at compression or over-extending at droop, and that everything clears through the steering range.
On a lowered car this matters more than it would at stock height, since the axle is working through angles Honda didn't plan for.
Fitment
2012-2015 Honda Civic Si
2013-2015 Acura ILX 2.4 manual
K24Z7 applications. Part number 510358 / 510359. Sold as a pair.
Who Should Run These
This is for the 9th gen Si or 2.4 ILX owner whose car is genuinely fast and still gets driven, and who's decided axles shouldn't be what limits it. Real power on the street, track days on the weekend, and a set that won't be the thing that ends your day. Confirm your engine if you're in an ILX, bolt them in, and check your travel before you lean on it.
Fits: 2012-2015 Honda Civic Si and 2013-2015 Acura ILX 2.4 manual (K24Z7). Does not fit: ILX 2.0 automatic. Part number: 510358 / 510359. Rating: 700 to 1000 wheel horsepower depending on application. Material: 300M bar and splined stub, chromoly CV housing. Includes: axle pair. Warranty: 1 year. Note: non-refundable after installation.
2013-2015 Acura ILX
2012-2015 Honda Civic Si