Also available in 2.500" ID: 4" Long | 8" Long | All Flex Coupling sizes
304 STAINLESS FLEX COUPLING WITH INTERLOCK LINER — ISOLATES ENGINE MOVEMENT AND VIBRATION FROM YOUR EXHAUST
This 2.500" ID x 6" long flex coupling is a mid-length option that balances packaging space with angular movement (3°–5°). Both ends are a slip-fit for 2.500" OD tube, so the tube slides into the coupling for easy alignment before welding.
Every engine moves on its mounts, especially under load. Weld a rigid exhaust to it and that movement ends up in your welds, flanges and hangers. Adding a flex coupling lets the exhaust move with the engine instead of fighting it, so welds last longer and less vibration makes it into the cabin.
FEATURES
- 100% 304 stainless construction: braided exterior, 2-ply bellows, interlock liner and end caps
- Smooth-flowing interlock liner (non-directional, can be installed either way)
- Outer braid protects the bellows and limits over-extension
- Slip-fit inlet and outlet for easy alignment and welding
- Overall OD (braid): 3.622" (92 mm)
Full specifications are listed in the spec table at the bottom of this page. Nominal dimensions; material tolerances apply. A dimensional drawing is included in the image gallery.
CHOOSING A LENGTH
Longer couplings allow more angular movement. The bend angles below are the most each length should see in service, not a target for installation.
| Length |
Max Bend Angle |
| 4" |
2°–3° |
| 6" (this coupling) |
3°–5° |
| 8" |
5°–8° |
| 10" |
6°–9° |
WHERE TO USE IT
- Downpipes and mid-pipes, after the turbo
- Close to the engine, where engine movement is greatest (for example, right after the manifold on transverse-engine cars)
- Non-turbo exhaust systems
IMPORTANT: NOT FOR PRE-TURBO USE. The interlock liner is not intended for turbo manifolds or any location before the turbo(s). The heat in those locations can degrade the interlock liner, and pieces of it could damage the turbo. Ace Race Parts is not responsible for damage caused by using this flex coupling in pre-turbo applications or in the direct line of induction of the turbo(s). For turbo manifolds and other pre-turbo locations, use our Flex Bellows with a solid inner liner.
INSTALLATION TIPS
- Install the coupling at its free length. Don't compress, stretch or twist it.
- Line up both tubes before welding. A flex coupling absorbs movement while driving; it isn't meant to correct misaligned pipes.
- Support the exhaust with hangers on both sides so the coupling isn't carrying the system's weight.
- Keep weld spatter off the braid, and don't let the welder's ground current pass through the coupling.
MATCHING PARTS
Pair this coupling with our 304 stainless tube, 304 mandrel bends and 304 V-band clamps and flanges. Questions about a specific part? Email us at support@aceraceparts.com.
