PRODUCT DETAILS
Driveshaft Shop X4 700HP Axle Set - 1988-1991 Civic & CRX (B-Series Cable)
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 an EF running a B-series cable transmission and real power, this is the tier that stops axles being the weak link.
Cable B-Series, But Not Y1 Or S1
Read this before ordering, because the exclusion matters.
These fit B-series cable transmissions with the Y2, A1, and J1 codes.
They do not fit the Y1 or S1. Those transmissions take different axles, and they aren't interchangeable.
If you're unsure which you've got, check your intermediate bar hanger bracket. A Y1 carries SH3 on the casting. If yours reads SH3, this isn't your set.
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 typically fail in torsion rather than bending, so material strength through the bar is what 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
Worth understanding the positioning, because it's specific.
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 all in the same week.
On an EF making real power, that's usually the profile. These cars are light, they're quick when built, and they mostly still get driven.
Direct Bolt-In
No hub change, no modification, no adapting anything. These go in where your existing axles came out, which keeps the job straightforward and keeps the cost to axles rather than an entire package.
Non-Refundable After Installation
Worth stating clearly. Once installed these can't be returned, which is standard for driveline components at this level.
That's another reason to check your transmission code first. Confirming a casting mark costs you two minutes. Ordering wrong costs considerably more.
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 or swapped EF this matters more than it would on stock height, since the axle is working through angles Honda didn't plan for.
Fitment
1988-1991 Honda Civic
1988-1991 Honda CRX
B-series cable transmissions: Y2, A1, and J1. Does not fit Y1 or S1 cable transmissions.
Part number 510499 / 510014. Sold as a pair.
Who Should Run These
This is for the EF 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 transmission code, bolt them in, and check your travel before you lean on it.
Fits: 1988-1991 Honda Civic and CRX with B-series cable transmission (Y2, A1, J1). Does not fit: Y1 or S1 cable transmissions. Part number: 510499 / 510014. 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.
1988-1991 Honda Civic
1988-1991 Honda CRX