What happens when tuners realize the hybrid HP/TQ numbers?

[heady]

The main thing that holds back the peak power in the hybrid is the relatively small battery; you can only pull so much current out of it safely, based on the C-rate specification of the cells. Adding batteries and capacity to most EVs, PHEVs, and hybrids is relatively easy, you simply tie into the high voltage bus with a matching voltage battery and add a contactor, you can see the examples of this on forums and youtube across the internet, look for range extending trailers, etc - the cars don't actually care where the electrons are coming from or going to on the high voltage bus.

So, that being said, what happens when an enterprising tuner actually realizes that the stock 2025 hybrid is a 393 HP, 405 lb-ft power train bolted to a 405 lb-ft rated transmission?

edit 11 July 2025:

Post #87 explains the complete function of the transmission including the gearing and planetary, and provides a spreadsheet to model the behavior of the powertrain in different circumstances.

Post #88 provides the explanation of what happens when you have enough battery capacity to use the planetary as a combiner, two inputs, instead of in the power split, two outputs mode.

Post #104 includes the live data capture that was used to verify the spreadsheet values with a wide open throttle run from 0 to 85 MPH.

Sponsored

 

[710-oil-614]

You can't take the max power numbers from MG and ICE and combine them for the maximum power. It doesn't quite work that way.

While Ford is understating the combined power output of the hybrid drivetrain it is nowhere near the power numbers you are stating.

 

[heady]

Actually you quite easily can, the stated figures are peak power capabilities of the motors and inverters at the rated voltage in the current packaging, which in this power train is quite a low voltage. The real limits are inverter IGBT current limits and thermal limits, and peak power can be pushed even further by increasing the bus voltage from the low 200's to the EV-like 400's, within the limits of whichever inverter you decide to use and the insulation breakdown voltage on the windings, which is also going to be in the 400's at minimum...

After having tuned DIY electrics as a hobby for many years, this could be a fun one to play with if someone was interested in tuning the OEM locked down and undocumented stuff!

 

[heady]

*It is possible, and maybe even most likely, that the published motor/inverter HP/TQ numbers are already spec'd at 450 volts input, as it is a power train designed for hybrids and plug in hybrids, just like the Escape. It would be a shame if there wasn't more headroom, but it's cool that Ford could launch a RAV4 power competitive product turn-key once, and if, they pull the trigger on the PHEV version.

edit: Also, it's an oversimplification on my part, and 710-oil-614 is almost certainly correct that it's not actually that simple to just add all the numbers together to come to a total, at least not for HP (you can add them all together for the TQ, as the max TQ of electric motors is available at any RPM below the torque knee. But, the HP is RPM dependent. So, the traction motor will need to be above a certain minimum RPM to reach its rated HP figure, which being directly coupled to the wheels, means that maximum power from that motor is only available above certain road speeds. For the "generator/starter motor" this and its torque will also be dependent on what RPM it is spinning at to keep the planetary ratio adjusted for the engines HP peak RPM

 

[OWP]

I'd like to see someone tune a hybrid, I'm all for modifying everything. If someone does they better be prepared for the usual group of "why do that? its not a hot rod" people

 

[phoneguyinpgh]

MG2s function is as traction motor, meaning it provides propulsion or regenerative breaking. MG1 does a lot more. It can provide extra electric propulsion if the ICE is not running but it is primarily used as the ICE starter, an alternator to recharge the HVB when the ICE is running but the vehicle is stopped and primarily to vary the gear ratio between the ICE and the planetary set's ring gear which is connected to the differential via another gear. When MG1 turns in one direction it provides gear reduction, the ratio is dependent on how fast it is turning. When MG1 turns in the other direction it provides an overdrive, the ratio again dependent on how fast MG1 is turning. It takes electrical power to control the direction and speed of MG1. That power does not add to the power from the ICE or MG2. In fact, when running on the ICE with a depleted battery, electrical power will be tapped from MG2, which is always turning when the wheels are turning, to supply electrical power to regulate MG1s direction and speed. That is one reason MG2 is larger than MG1. Also that is why The HP and torque specs are limited to pretty much what the ICE can provide.

Further, the type of motors being used in the hybrid transmission appear to be 3 phase, delta connected, variable frequency, synchronous AC motors. (I'm not sure how many poles each has) So the peak torque is always available from the electric motors from 0 RPM to peak RPM and their HP will increase as the speed increases.

Higher capacity batteries would permit the Maverick to be a PHEV like the Escape but would not give it the power to make it an electric dragster or able to tow 10,000 lbs.

 

[heady]

There's nothing physically that prevents MG1 from adding power during engine on run in such a transmission design that I know of, it may be that it does not in the Ford tuning, but mechanically and electrically speaking, it can be tuned to have a positive torque output while the engine is also on. With a bigger battery and RAV4 like numbers, it should be quite a capable little power plant, there's a good reason the RAV4 PHEV was the quickest Toyota in the lineup with a little 2.5L like the Maverick until the Supra and GR Corolla came out.

 

[hdave]

From what I remember, the battery is under the passenger side and Ford had a blank spot for another battery under the driver side, so it sounds like battery capacity can be doubled.

With that being said, this isn't a machine with electronics, it's a computer with mechanical parts.
Everything needs to go through the computer and I bet it would be a nightmare dealing with that since most tuners aren't computer programmers who can open up Ford's code.

 

[HeyBales]

The system total torque reference value on pre-25's is 245.6 ft/lbs.
Maybe the same on 25's.

Other values that may be different on 25's due to EV allowed to go to 15% power before ICE on, compared to 10% on pre-25's.
From the system PID's, the Max HVB charge is 32 kW, discharge is 27 kW - or 145 A / 123 A.

 

[Clarkdonbran]

 

[710-oil-614]

"Towelie - you're the worst character ever"

"I....I know....."

 

[heady]

From what I remember, the battery is under the passenger side and Ford had a blank spot for another battery under the driver side, so it sounds like battery capacity can be doubled.

With that being said, this isn't a machine with electronics, it's a computer with mechanical parts.
Everything needs to go through the computer and I bet it would be a nightmare dealing with that since most tuners aren't computer programmers who can open up Ford's code.

As long as it's being done in the normal tuning way of modifying lookup tables and soft limit values, it should be very much like tuning any other PCM/ECM, but it would be unfamiliar to a normal tuner until they understood and fully mapped out the torque and speed tables, which also controls the planetary gear ratio as well, for one extra level of challenge.

MG2/traction motor tuning would be dead simple and take it to the inverter current limit and hold it until thermal limits as long as you've got the additional battery C rate to support it, MG1 starter/generator tuning is a little more complex, and might not be possible depending on how Ford coded the PCM equation.

"Tuners" that use "sensor fooling" and other cheap tricks would be of no use tuning a hybrid, though. Beyond factory inverter limits, you'd need to modify or upgrade the inverters for more current, if there's additional thermal headroom.

 

[colinl]

what happens when an enterprising tuner actually realizes that the stock 2025 hybrid is a 393 HP, 376 lb-ft power train bolted to a 405 lb-ft rated transmission?

As long as it's being done in the normal tuning way of modifying lookup tables and soft limit values, it should be very much like tuning any other PCM/ECM, but it would be unfamiliar to a normal tuner until they understood and fully mapped out the torque and speed tables, which also controls the planetary gear ratio as well, for one extra level of challenge.

what in the youtube mechanic nonsense are you spouting here? 400 horsepower lol.

tuning a gas engine is very different than what you're suggesting, which seems to be a belief that you can pull more current or increase the voltage and get more output from the hybrid electric motors? a gas engine can add more fuel, lean the fuel mix, add boost, advance timing, etc.

you aren't getting more output from the electric motors without premature failure unless you are talking about changing the windings, magnets, etc. this is NOT at all like tuning a gas powertrain.

 

[heady]

It's actually significantly easier to tune an electric motor, as there is no such thing as a HP rating on an electric motor, merely a duty cycle and current beyond which it begins to melt down. When you have modern equipment like three phase electric permanent magnet motors coupled to inverter drives with field weakening, the only real limitation is igbt current limit and motor temperature.

This is why you can take a "750 watt" electric bicycle bldc motor and pump about 20kw though it for a short drag race at over 100mph, if you know what you are doing.

 

[MetalThunder]

You first - theories are only as good as results BUT i'd recommend you understand about HV battery degradation

Cheers

Sponsored