OVERVIEW
Genuine VW/Audi turbocharger downpipe stud, part number N-907-787-01. This original threaded stud provides the assigned attachment point for securing the downpipe to the turbocharger outlet flange on the configurations below. It is supplied individually for exhaust removal, flange repair or replacement of damaged mounting hardware. The cataloged arrangement uses four studs per turbocharger.
Technical details
- Original number: N-907-787-01 / N90778701.
- Published nominal size: M10 x 23.5.
- Double-ended threaded stud with a central shoulder.
- Application: assigned turbocharger outlet flange-to-downpipe attachment.
- One stud supplied. Mating nut, outlet sealing gasket, turbocharger and downpipe are separate.
The stud screws into the assigned flange position and provides the threaded attachment for the mating exhaust component. Correct hardware and the specified gasket work together to form the intended outlet connection. The stud itself is not an exhaust seal.
Nearby exhaust joints can use different studs, nuts or bolts. Select this part by original number and actual flange position, rather than assuming that every turbocharger outlet uses the same M10 hardware.
Common reasons to replace
Replacement may be needed when exhaust disassembly reveals damaged threads, a broken stud, deformation or corrosion that prevents reliable attachment. Renew hardware wherever the factory procedure requires replacement after removal.
Heat cycling and earlier repair work can make outlet fasteners difficult to remove or leave damaged threads in the stud or flange. Inspect the complete mounting connection before fitting a new stud.
Exhaust noise, leakage or a loose outlet connection requires diagnosis of the flange, gasket, mating component and support hardware. A new stud cannot repair a cracked flange, damaged turbocharger thread, distorted downpipe connection or failed gasket. Correct those faults before reassembly.
Installation and service notes
Follow the factory procedure for the exact turbocharger outlet arrangement. Allow the exhaust assembly to cool and support the connected exhaust component as prescribed before releasing the flange hardware.
Inspect the turbocharger flange threads, mating faces and stud positions. Remove damaged hardware using the appropriate repair procedure without damaging the threaded mounting hole. Do not install a new stud into compromised threads without completing the required repair.
Fit the correct stud in its assigned position using the prescribed installation method and thread preparation. Observe the specified installed position rather than applying an assumed universal insertion depth.
Use the correct separate gasket and mating nut. Position the exhaust connection correctly and follow the prescribed tightening sequence, torque and any additional angle for that joint.
Do not transfer a tightening value from a different exhaust flange or an unrelated M10 fastener. Add lubricant, anti-seize or thread treatment only when the applicable factory procedure specifies it.
Complete the required exhaust clearance and leak checks after assembly. Confirm that the connected exhaust is supported correctly and that every assigned flange position contains the proper hardware. This listing supplies one original stud; order the quantity needed for the repair.
Fitment
| Vehicle | Model years | Engine | Configuration | Application restrictions |
|---|---|---|---|---|
| Audi S4 | 2000–2002 | 2.7L twin-turbocharged gasoline V6, APB | B5 sedan, quattro; 6-speed manual | Factory K03/K04-pattern turbocharger-to-downpipe stud. Four required per turbocharger in this arrangement; one supplied. Confirm N90778701 and actual outlet flange. Aftermarket hardware may differ. |
| Audi S4 Avant | 2001–2002 | 2.7L twin-turbocharged gasoline V6, APB | B5 wagon, quattro; 6-speed manual | Factory K03/K04-pattern turbocharger-to-downpipe stud. Four required per turbocharger in this arrangement; one supplied. Confirm N90778701 and actual outlet flange. Aftermarket hardware may differ. |
Confirm the original stud number and turbocharger outlet flange arrangement before ordering. One stud supplied.