Max Power for OE HPFP's?
Senior Member
Joined: Mar 2025
Posts: 406
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From: Toronto
2025 AMG G 63 SUV /// 2025 AMG GT 63 S E Performance 4 Door Coupé
The M178 with stock TCU tune and stock HPFP’s are good for around 600 WHP, so about 730 to 750 BHP.
The pumps are good for more HP but the TCU holds the HP back without a tune for torque limits and clutch pressure etc.
If you’re going to do an ECU and TCU tune without changing the fuel pumps you’ll get close to 650 WHP. With new pumps up to 800 WHP. With injectors, turbos, race gas etc. you can get up to the 1000 mark.
The pumps are good for more HP but the TCU holds the HP back without a tune for torque limits and clutch pressure etc.
If you’re going to do an ECU and TCU tune without changing the fuel pumps you’ll get close to 650 WHP. With new pumps up to 800 WHP. With injectors, turbos, race gas etc. you can get up to the 1000 mark.
Thread Starter
Senior Member
Joined: May 2015
Posts: 253
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From: Scottsdale, AZ
2017 AMG GTS
The M178 with stock TCU tune and stock HPFP’s are good for around 600 WHP, so about 730 to 750 BHP.
The pumps are good for more HP but the TCU holds the HP back without a tune for torque limits and clutch pressure etc.
If you’re going to do an ECU and TCU tune without changing the fuel pumps you’ll get close to 650 WHP. With new pumps up to 800 WHP. With injectors, turbos, race gas etc. you can get up to the 1000 mark.
The pumps are good for more HP but the TCU holds the HP back without a tune for torque limits and clutch pressure etc.
If you’re going to do an ECU and TCU tune without changing the fuel pumps you’ll get close to 650 WHP. With new pumps up to 800 WHP. With injectors, turbos, race gas etc. you can get up to the 1000 mark.
Senior Member
Joined: Mar 2025
Posts: 406
Likes: 147
From: Toronto
2025 AMG G 63 SUV /// 2025 AMG GT 63 S E Performance 4 Door Coupé
My pleasure! New pumps and a quality ECU/TCU tune and you’ll be right where you want to be.
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2018 Mercedes-AMG GT R Evo
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many factors will determine your maximum for the OE pumps. The fuel octane, the oxygen content of the fuel, whether you want to use any additional margin (ie meth), the tuner, etc.
I’m running about 250hp more at the wheels over stock with the stock pumps. I wouldn’t push it any further and still have a safety margin.
I’m running about 250hp more at the wheels over stock with the stock pumps. I wouldn’t push it any further and still have a safety margin.
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AMG GTR
A fair few tuners in the UK are happy to get a GTR running over 900nm, seems way over what the box can handle, on paper!
The factory transaxle is officially rated for 750 crank Nm (553 lb-ft), with an unofficial upper tolerance of around 820 Nm, as reported by MBNRG. To maximize horsepower while maintaining reliability, the safest approach is a custom tune that flattens the torque curve across the mid-to-upper RPM range.
With the GTC and GTR OE turbo setups, an ideal strategy is to hold torque at roughly 750–780 Nm between 3,000–5,500 RPM, then allow a controlled rise to 780–820 Nm from 5,500–6,500 RPM. Achieving this requires precise boost management, with peak boost pressure in the 24 psi range. This level of balance is difficult to dial in, and in practice, most well-executed calibrations I’ve seen—including my own setups—tend to plateau near 680 crank hp @ 6,500 RPM (assuming ~12% drivetrain loss from wheel to crank).
I don't have numbers for the GTS, but since it uses smaller turbos, it will be difficult to reach the 750nm and I don't see any benefit for a HPFP.
A critical safeguard is torque limiting in the lower gears: specifically, torque should be capped between 1,000–5,000 RPM in 1st and 2nd gear to prevent drivetrain shock loads.
The OE fuel pump is adequate to support the above power levels without starvation.
This combination provides a balance of peak performance, drivability, and transaxle longevity, rather than chasing numbers that risk premature hardware failure.
However, if you’re planning to push beyond these limits, you’ll need supporting upgrades:
- Reinforced clutch system (e.g., Dodson)
- Strengthened transaxle internals (e.g., PTG billet solutions)
- Higher-capacity turbos (with the tradeoff of added lag)
- High-pressure fuel pump (HPFP) upgrade
- Coordinated ECU and TCU calibrations
- Street / Daily Driving: Beyond ~750–780 Nm, the gains are marginal because traction becomes the limiting factor. Extra torque will mostly translate into drivetrain stress, heat, and shorter component life rather than usable performance on public roads.
- Track / Road Course: Here, usable power is about balance and consistency. A flat, predictable torque curve that carries strong but controlled power to redline is far more valuable than brute-force torque spikes. This makes the car more manageable mid-corner and improves lap-to-lap consistency without overloading the transaxle.
- Drag Racing / Roll Racing: Higher peak power numbers are beneficial, but only if the transaxle and clutch are upgraded. In this scenario, additional torque is useful, but the priority is ensuring driveline reliability and maintaining efficient power delivery throughout the run.
- If the goal is longevity and balanced performance, you want controlled torque (750–800 Nm) with a linear delivery.
- If the goal is maximum peak numbers for straight-line racing, then you need significant hardware upgrades to keep the platform alive at 820+ Nm.
Last edited by G. P; Aug 24, 2025 at 09:47 PM.
For stock turbos, it isn’t required—so don’t waste time or money on an HPFP unless you’re going that route.
https://www.gad-motors.de/50aqawgh9a...-gt%2Fgts-m178
