Product Description
MBRP UA9004 is a T409 stainless steel exhaust adapter that transitions 4" ID to 5" ID over a 7" length for clean, leak-free size changes in heavy-duty diesel systems. Built for longevity and easy fabrication, it’s the stainless counterpart to MBRP’s aluminized adapters.
- Material: T409 stainless steel
- Size: 4" inner diameter (inlet) to 5" inner diameter (outlet)
- Approx. length: 7"
- Universal straight adapter (slip fit), weld or clamp as needed
Fitment
Universal—works wherever you need to step from 4" pipe to 5" pipe on pickup and medium-duty diesel exhaust systems (e.g., transition sections, tailpipe/tip upsizing, custom turbo-back builds). Verify OD/ID on adjoining tubes and use appropriate MBRP hardware.
Cross-Reference / Alternatives (MBRP only)
- Stainless, 4" ID to 5" OD: MBRP UA9001
- Aluminized, 4" ID to 5" ID: MBRP UA2004
- Aluminized, 4" ID to 5" OD: MBRP UA2001
- Stainless, 3.5" ID to 4" OD: MBRP UA1007
- Universal polished tip, 4" inlet to 5" OD tip options: MBRP T5124
Helpful Notes
- Clamps are not included; weld for best results or use appropriate band clamps.
- T409 stainless offers excellent durability; surface discoloration is normal with heat cycles.
- Always mock-up and measure before cutting—confirm ID/OD ends on both mating tubes.
FAQ
Is the UA9004 a slip fit on both ends?
Yes—both ends are designed as slip fits sized for 4" ID and 5" ID mating. You can weld it in or secure with compatible band clamps.
When should I choose stainless (UA9004) over aluminized (UA2004)?
Pick stainless for long-term durability, winter/salted roads, or off-road abuse. Aluminized is a solid budget option for milder climates.
Will this help me run a 5" tip on a 4" system?
Yes. Use UA9004 to step to 5" tubing, then pair with an appropriate 5" OD tip like the MBRP T5124 (check inlet/OD matchups).
Do I need new clamps?
If you aren’t welding, yes—use quality band clamps matched to your pipe sizes. (Clamps sold separately.)
