Product Description
FLEECE FPE-34856 STAINLESS STEEL TURBO STUD KIT FOR S-300/S-400
Upgrade your turbo mounting hardware with the FLEECE FPE-34856 Stainless Steel Turbo Stud Kit for S-300/S-400 turbos. Built from aged 630 stainless steel right here in the USA, these studs deliver unrivaled corrosion resistance, superior clamping force, and ease of installation — key for serious turbo builds and high-temperature environments.
Key Features
- Made in USA from aged 630 stainless steel for strength and corrosion resistance.
- 4 mm internal hex head design makes installation cleaner and faster.
- Designed for turbos with flange thickness up to 3/8" (0.375″).
- Allows higher clamping force compared to standard hardware, supporting durability under boost.
- Corrosion-proof finish ensures long-term reliability in harsh conditions.
Fitment & Application
This kit is engineered for use with BorgWarner S-300 and S-400 series turbochargers (and equivalent flanged turbos) where flange thickness is 3/8" or less.
Note: This is a universal hardware kit — verify flange thickness and stud length against your specific turbo and manifold setup before installation.
Installation Notes
- Apply a light coat of anti-seize to the stud threads entering the manifold.
- Snug each stud by hand with the 4 mm Allen head; do not over-tighten.
- After turbo and gasket installation, torque nuts to 55 ft-lbs, then perform a hot re-torque after first heat cycle.
- Ensure flange thickness does not exceed 3/8″—this kit is not designed for thicker flanges.
Why Choose Fleece Turbo Stud Kit?
When you’re pushing boost, high-temperatures, and repeated heat cycles, your turbo flange hardware can be a weak link. The Fleece FPE-34856 kit solves that by combining premium materials, easy installation, and performance-grade design. Whether you’re running a built 5.9L Cummins, 6.7L Cummins, Duramax or other turbo platform using S-300/S-400 flanges, this hardware upgrade helps keep things sealed and solid so you can focus on performance.
Specifications for FLEECE FPE-34856
| Attribute | Value |
|---|---|
| Brand | Fleece Performance Engineering |
| Part Number | FPE-34856 |
| Kit Components | 4 × M10 aged 630 stainless studs with 4 mm internal hex + 4 × 12-point nuts |
| Material | Aged 630 stainless steel (USA) |
| Maximum Flange Thickness | 3/8″ (0.375″) |
| Torque Spec | 55 ft-lbs initial and after hot re-torque |
| UPC | 670875717152 |
| GTIN | 670875717152 |
| Shipping Info | Approx. 2 lb ship weight; packaged box ~4″ x 2″ x 5″ |
| Cross-Reference / Alternatives | FLEECE FPE-34772 (Exhaust manifold stud kit for 94-18 Cummins) – see related hardware upgrades |
| E-Codes | Not applicable |
| Prop 65 | WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov |
FAQ
Will the FPE-34856 studs fit any turbo flange or only S-300/S-400?
This kit is specifically designed for S-300 and S-400 series turbochargers (and equivalents) with a flange thickness up to 3/8″. It will not accommodate flanges significantly thicker without modification.
Why go with stainless steel studs instead of the factory hardware?
Factory hardware is often mild steel or lower grade and may stretch, corrode, or deform under high exhaust heat and boost loads. The aged 630 stainless used here resists corrosion and allows higher clamping force, which helps maintain flange integrity and turbo sealing over time.
Is a hot re-torque really required after installation?
Yes. Because of high exhaust temperatures and thermal expansion in turbo systems, Fleece recommends torquing the nuts to 55 ft-lbs and then re-torquing after the engine has run and reached thermal equilibrium (hot). This ensures the clamp load remains correct under actual conditions.
Can I use this kit for non-S300/S400 turbos if flange thickness is under 3/8″?
Potentially yes—if the flange thickness, stud engagement depth, thread size, and bolt circle match. However, this kit is optimized for S-300/S-400 style flanges and you should verify fitment carefully before use. For mis-matched flanges or unique layouts, a custom stud kit may be required.
What supporting hardware or upgrades should I consider when using this stud kit?
While the FPE-34856 stud kit secures your turbo properly, it's wise to also check or replace the turbo gasket, manifold bolts, and inspect flange surface flatness. If you’re running high boost or custom setups, premium gaskets (multi-layer or solid copper), upgraded manifolds, and proper alignment help ensure longevity and sealing integrity.
