ISR Performance Aluminum Modular BOV Flange - HKS Style BOV's

The ISR Performance Aluminum Modular BOV Flange is a two-piece weld-on flange designed for HKS-style blow-off valves. The two-piece design lets you weld the bottom portion to your charge pipe, then thread the HKS-pattern top piece on, with the ability to swap to a different BOV brand later by changing the top piece (HKS or GReddy compatible).

What It Does

Welding a BOV flange directly to a charge pipe is the standard approach, but it locks you into one BOV pattern forever. The ISR modular flange splits that into two pieces: weld the bottom portion to the pipe (which is easier to weld because the top piece comes off), then thread the BOV-specific top piece on. Want to switch from HKS to GReddy later? Unscrew the top piece and replace it with the GReddy variant - no rewelding required.

HKS-Style BOV Compatibility

This flange ships configured for HKS-style BOVs. The top portion can be swapped for a GReddy-style top piece (sold separately) to convert between HKS and GReddy BOVs without rewelding the bottom flange to the pipe.

Why Two-Piece Matters for Welding

Single-piece BOV flanges are awkward to weld because the BOV-pattern face is sensitive to heat warping. With the two-piece design, you weld only the simpler bottom flange to the pipe, then thread the precision BOV face on once welding is done. Cleaner welds, fewer heat warp issues, and a flat sealing surface.

Fitment

• Universal application for charge pipe BOV installation
• HKS-style BOVs (top piece swappable for GReddy compatibility - sold separately)

What's in the Box

• 1x ISR Performance aluminum modular BOV flange (two pieces - weld-on bottom + HKS-pattern top)

Product Details

Brand: ISR Performance

Part Number: IS-FLA-002

Type: Modular Aluminum BOV Flange (Weld-On)

Material: Aluminum

BOV Pattern (as shipped): HKS style

Convertible To: GReddy style (top piece sold separately)

Design: Two-piece - weld-on bottom + threaded top

Benefit: Swap BOV brands later by changing top piece, no rewelding required

Application: Universal charge pipe / hotpipe BOV installation

Sold: Complete two-piece flange (HKS configuration)

Legality: Off-road and competition use only