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The Stainless Bros 2.50in Diameter 1.5D / 3.75in CLR 90 Degree Bend Leg Mandrel Bend (part number 601-06356-4150) is a high-quality 90-degree turn section for 2.5-inch custom exhaust and turbo piping builds. Formed from 16-gauge 304 stainless steel using a precision mandrel-bending process, this component delivers a perfectly round cross-section through the full 90-degree arc. The 1.5D loose radius provides a gradual sweep at 3.75in CLR, resulting in lower flow restriction and reduced turbulence compared to tighter 1D bends at this diameter.
Features and Benefits
- 16-gauge (0.065in wall) 304 stainless steel withstands exhaust heat and resists rust in all climates
- Mandrel-bent bore stays perfectly round through the 90-degree sweep, eliminating flow restrictions
- 1.5D loose radius (3.75in CLR) minimizes backpressure on 2.5in exhaust and intake systems
- Straight leg on each end provides material for trimming to exact fitment requirements
- Polished exterior finish makes alignment and weld prep straightforward
- Compatible with standard 2.5in exhaust couplers, clamps, and V-band flanges
- Consistent wall thickness supports reliable TIG and MIG welds without burn-through
- Ideal for downpipe bends, cat-back routing, and intercooler charge piping at the 2.5in diameter
Specifications
| Specification | Detail |
|---|---|
| Part Number | 601-06356-4150 |
| Brand | Stainless Bros |
| Material | 304 Stainless Steel |
| Wall Thickness | 16 gauge / 0.065in |
| Tube OD | 2.50in |
| Bend Radius | 1.5D / 3.75in CLR |
| Bend Angle | 90 Degree |
| Finish | Polished OD |
| Warranty | Stainless Bros limited warranty |
What's Included
- 1 x Stainless Bros 2.5in 90-degree 1.5D mandrel bend (part 601-06356-4150)
- Straight leg sections on each end for trimming
Frequently Asked Questions
What is the tube OD for the 601-06356-4150?
The outside diameter is 2.50 inches. Use 2.5in couplers, clamps, or flanges rated for 2.5in OD tubing when mating to other components.
What is the difference between 1D and 1.5D radius at 2.5in diameter?
A 1D radius gives a centerline radius equal to the diameter (2.5in CLR), producing a tight bend that can increase backpressure. The 1.5D radius in this bend gives a 3.75in CLR, creating a wider arc that preserves exhaust velocity better in high-flow applications.
Is the 601-06356-4150 suitable for a 2.5in turboback exhaust build?
Yes. The 2.5in OD with 1.5D radius is a common specification for turboback and cat-back exhaust systems on four-cylinder turbocharged vehicles. The smooth bore maximizes flow and the stainless construction handles sustained exhaust temperatures.
Can I cut the leg sections shorter?
Yes. The straight legs are provided for trimming. Use a tubing cutter or angle grinder with a cutoff disc to cut to the required length. Deburr all cut ends before welding to prevent flow obstructions.
What filler rod is recommended for welding this to mild steel pipe?
ER309L is the standard choice for welding 304 stainless to mild steel. For stainless-to-stainless joints, use ER308L. Both require argon or argon/helium shielding gas for clean, porosity-free welds.
What is the wall thickness of this Stainless Bros bend?
The wall is 16 gauge / 0.065 inches, consistent throughout the straight legs and the curved section. This provides sufficient rigidity for unsupported mounting points while keeping weight manageable.
Does this mandrel bend require any straightening or correction out of the box?
No. Stainless Bros mandrel bends are produced to consistent dimensional tolerances and ship ready to cut and weld. The 90-degree angle and leg dimensions are verified during manufacturing.
Is this the same as the 601-06356-4100 part number?
No. The 601-06356-4100 is a 1D tight-radius version of this bend (2.5in CLR), while the 601-06356-4150 is the 1.5D loose-radius version (3.75in CLR). The 1.5D version provides better flow characteristics in most exhaust applications.
Installation Instructions
- Plan the routing of the 2.5in exhaust or piping system and confirm the 90-degree bend angle and leg lengths required before cutting.
- Dry-fit the 601-06356-4150 in the system to verify alignment and clearance with surrounding components.
- Mark the cut lines on the leg sections and trim to length using a tubing cutter or cutoff wheel.
- Deburr all cut ends to remove sharp edges and facilitate weld prep.
- Clean weld areas with acetone prior to welding.
- Tack-weld in position before completing full circumferential welds.
- Inspect welds and verify no leaks or cracks before installation on the vehicle.
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