The Borla XR-1 Multi-Core is a racing muffler with a 3in center inlet and 3in center outlet on a 4.25in x 7.88in oval body (16in body, 21in overall), originally cataloged for rotary-engine vehicles but usable across high-horsepower builds. Its patented Multi-Core 4-tube design flows better than straight tubing for maximum horsepower and torque. T-304 stainless with a reversible design.
| Type | XR-1 Multi-Core racing muffler |
| Inlet/Outlet | 3in inlet / 3in outlet |
| Configuration | Center / Center |
| Body | Oval - 4.25in x 7.88in - 16in body - 21in overall |
| Core | Patented Multi-Core 4-tube |
| Material | T-304 stainless steel - reversible |
| Part Number | 400371 |
Shipping: In-stock orders placed before 3 PM EST ship the same day, and everything else ships within 24 hours. Standard, expedited, and overnight options are available at checkout. Backordered items ship as soon as we get them back in stock. Contact us for lead times. See the full Shipping Policy.
Returns: 30-day returns on new, unused items in original packaging. See the full Refund Policy.
