C5 Corvette 58 PSI Filter/Regulator LS-Swap Plumbing: Diagram, Parts & Install

C5 Corvette 58 PSI Filter/Regulator LS-Swap Plumbing: Diagram, Parts & Install

C5 Corvette 58 PSI Filter/Regulator — LS Swap Plumbing Diagram & Parts List

The C5 Corvette filter/regulator (fixed 58 psi / 4 bar) makes a clean return-less LS fuel system: one feed to the rail, return handled at the filter/reg. Below is the layout, exact parts, and a beginner-safe install sequence. Works for LS1/LS6/Gen III/IV and common TBSS/NBS intake upgrades.

Quick Diagram

[Tank] ──> (In-tank Pump) ──> IN on C5 Filter/Reg (58 psi) ──> OUT to fuel rail (single feed)
                                   └── RETURN back to tank

Filter spec: Pressure-side EFI filtration should be ≤ 10 μm. Choose an E85-compatible element if you run ethanol blends. Our corvette C5 regulator is rated at ~5 Micron 

Two Ways to Plumb It

A) C5 Filter/Reg with Integrated AN-6 Males (cleanest)

  • Pump → AN-6 hose → IN (male AN-6)
  • OUT (male AN-6) → rail feed (AN-6)
  • RETURN (male AN-6) → tank return (AN-6)

B) OEM-style C5 Filter/Reg with Quick-Connects

  • Typical sizes: 3/8" feed & outlet, 5/16" return
  • Use EFI Quick-Connect → AN-6 adapters with threaded locking nuts (won’t pop off like plastic clips). The nut’s cutout lets you engage even on short stubs—seat the lip, then thread together. Lightly oil the small internal O-rings before tightening.

Recommended Parts

Helpful Add-Ons

Install Steps (beginner-safe)

  1. Plan sizes & routing: AN-6 feed/return covers most NA builds
  2. Mount the C5 filter/regulator near the tank on the frame rail (away from heat). Observe flow arrow.
  3. Pump → IN: Run AN-6 PTFE from pump outlet to IN. For QC ports, use 3/8" QC → AN-6 threaded-nut adapter; lightly oil O-rings.
  4. OUT → Rail: AN-6 PTFE from OUT to rail feed. If the rail is QC, use a 3/8" QC → AN-6 threaded-nut adapter.
  5. RETURN → Tank: AN-6 from RETURN back to tank. If adding a bulkhead, drill & deburr; use PTFE sealing washers. Submerge the return where possible to reduce aeration.
  6. Secure & protect: P-clamps every ~18–24". Avoid sharp edges; add heat sleeve if needed.
  7. Assemble fittings correctly: For PTFE ends, seat the olive squarely. Tighten with AN wrenches—do not over-torque. Wrap the cut with tape before using shears to control fray.
  8. Prime & pressure-check: Key-on prime. Verify ~58 psi at the rail (use the gauge port). Check for leaks at pressure and at idle.

FAQs

Is the C5 Corvette filter/regulator return-less or return-style?
Return-less at the rail. You run a single feed forward; the unit regulates to 58 psi and returns excess fuel via its RETURN port at the rear.
What are the port sizes?
OEM-style units commonly use 3/8" QC for feed & outlet and 5/16" QC for return. Our integrated version uses AN-6 male on all three for a cleaner build.
Do I still need a separate filter?
The C5 combo includes a fine element. Our guidance: pressure-side EFI filtration should be ≤ 10 μm. If you run the C5 unit as designed, you’re covered. Standalone regulators require a separate ≤10 µm post-pump filter.
What hose size should I use?
Most swaps: AN-6 feed and return. Step to AN-8 feed for long runs, higher HP, or heavy E85. Always use PTFE for ethanol blends and zero-odor garages.
Where should I mount it?
Near the tank on the frame rail to keep the return short and reduce heat/vapor issues. Keep away from exhaust.
When should I use a return-style regulator up front?
Very high pump flows (340+ LPH), boosted applications, or when you want adjustable pressure. In that case, use a high-flow ≤10 µm filter and plumb a return from the engine bay.

Buy the Return-less LS Kit   PTFE Hose Bundles · Adapters · Fuel Filters

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