FL5 / DE5 Fueling Guide: HPFP, Injectors & LPFP Upgrades for Turbo Builds
By Thomas Germano
If you're upgrading the turbo on your FL5 Civic Type R or DE5 Integra Type S and not upgrading fueling, you're doing it wrong.
More airflow means more fuel demand. That’s not opinion — that’s physics.
On the K20C1 platform, rail pressure stability is the difference between a clean 500+ WHP pull and a very expensive mistake.
Why Fueling Is Non-Negotiable
The factory direct injection system runs around 200 bar (2900 psi). That’s fine for stock. Once you add boost and airflow, it starts hitting its ceiling.
• Rail pressure drop at high RPM
• Timing getting yanked
• Boost taper (ECU protecting itself)
• Lean conditions
• Long-term reliability issues
Yes, you can “get away with it” on conservative boost.
No, that’s not optimizing your setup.
Stop being cheap. Support the airflow properly.
Fueling Upgrade Comparison
| Component | Option | Highlights | Best For |
|---|---|---|---|
| HPFP | Full-Race | +68% flow Includes upgraded high-pressure line No drilling required |
Max effort builds |
| HPFP | XDI EVO / HPFP60 | +36% to +63% flow Good hybrid options |
Street + flex builds |
| Injectors | Hondata 1530cc | ~44–47% more flow 550+ HP tested on E85 Smooth idle |
Most builds |
| Injectors | Hondata 2000cc | Actual 2080cc ~90% more flow 240+ bar tested |
500+ WHP |
| LPFP | Hondata / DW300C | Higher supply capacity E85 compatible |
Ethanol / big boost |
The 5/64" Fuel Line Restriction
The factory high-pressure feed line has an internal restriction.
Drill to 5/64"
Yes it works. But clean it properly. Metal shavings in your DI system is a quick way to ruin your day.
Replace the Line
Cleaner and smarter. Some HPFP kits include upgraded lines so you don’t modify OEM parts.
Injector Upgrades (Where Power Headroom Lives)
Hondata 1530cc – The Sweet Spot
- ~44–47% more flow vs stock (1059cc)
- Calibrated at 100 bar
- E85 compatible
- OEM-like spray pattern
- Designed & manufactured in USA
Tested to 550+ HP on E85. Perfect for most hybrid and flex setups.
Smooth idle. Easy to tune. Reliable.
Hondata 2000cc – 500+ WHP Builds
- Actual Flow Rate: 2080cc
- ~90% more flow than stock
- Calibrated at 100 bar
- Tested beyond 240 bar
- E85 compatible
- OEM-like atomization
- Matched set of 4
Tested to 550+ HP on E85, indicating serious race fuel headroom.
These are the best injectors available for this platform in my opinion.
They idle smooth and tuners love them. That matters.
Hondata Complete Fuel System Kit
If you want a fully engineered solution instead of piecing random parts together:
- High flow ethanol-rated LP fuel line
- High flow DI pump
- High pressure fuel line
- High flow injectors
- FlashPro calibration support
Hondata states this system delivers ~24% more fuel flow over stock and supports reliable power gains.
Unlock codes are single-use and non-refundable.
Low Pressure Fuel Pump (LPFP)
As boost and ethanol go up, supply from the tank becomes critical.
If DI fuel pressure drops in logs, upgrade the LPFP.
Log everything. Don’t guess.
Recommended Fueling Stages + Tuning
Stage 1 – Hybrid Pump Gas
HPFP + address restrictionTuning: Hondata FlashPro with experienced tuner
Stage 2 – Flex Fuel Builds
HPFP + 1530cc injectors + LPFPTuning: Hondata + CANFlex
Stage 3 – Big Turbo / 500+ WHP
Full-Race HPFP + 2000cc injectors + upgraded LPFPTuning: Hondata maxed properly or MoTeC for full control
Build headroom. Build reliability. Build it once.