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Discussion Starter · #1 ·
I was wondering if anyone has considered upgrading their MDX hybrid braking system with better rotors, calipers and pads considering the OEM brakes are not that great.

The question I would have is that since the hybrid uses regenerative braking to charge the battery, would it be even possible to upgrade the brake system? or it really doesn't matter because the regenerative braking is something just attached to the OEM brake system?

Thank you!
 

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The regenerative braking system consists on the electric motors turning into generators, Its not really something to do with the physical brakes themselves.

When they switch into generators the LOAD is so high they act like brakes. That is why one of the most intensive parasitic draws in a gasoline engine is the alternator.
 

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I read somewhere that the front brakes on the Hybrid were an upgrade from the 12.5" on the gas MDX to 13" on the Hybrid. Trying to find that reference now....
 

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Discussion Starter · #4 ·
I was trying to figure out how the regenerative braking system works but i could not find any articles or literature on it. I was thinking about upgrading to bigger brakes for better stopping power. I feel like i need to apply extra pressure on the brake pedal to get the car to stop. very weird feeling coming from a lexus IS350 F sport with performance brakes.
 

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I found that the Hybrid uses a different part number for the front disc (17" on the Hybrid). As for the regenerative braking I found a very technical explanation on the Acura press release for the Hybrid. Basically the computer splits the braking between friction and EV...

Electric Servo Brake System
The MDX Sport Hybrid SH-AWD's electric servo brake system maximizes regenerative braking capability for improved fuel efficiency. The braking system is fully hydraulic from the master cylinder all the way to the 4-wheel disc brakes, just like a traditional braking system. The key difference is that the braking function is electronically controlled rather than a purely mechanical activation, allowing regenerative braking from the front and rear electric motors to slow the vehicle, rather than the hydraulic friction brakes, under most circumstances. Besides its payoff in efficiency, the system offers excellent feel and feedback for the driver through the brake pedal.
When the driver applies the brake pedal, a signal is sent to the vehicle's Electronic Control Unit (ECU), which determines the appropriate amount of braking force to assign to regenerative braking through the electric motors and to the hydraulic friction braking system. In many cases, friction braking is not needed until the vehicle speed drops below 9 mph, as the vehicle slows to a final stop to promote a smooth end of the stop. Midway between the master cylinder and the calipers is a separate motorized electronic actuator. This actuator receives an electronic signal, generated in the master cylinder module that precisely defines how the driver has applied the brakes – soft or hard, slow or fast. The ABS unit then directly apportions hydraulic pressure to the brake calipers at each wheel. While the MDX SH-AWD uses a 10.5-inch vacuum booster to assist the driver in applying needed brake pressure, the MDX Sport Hybrid SH-AWD uses an electric servo brake actuator
 

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I read somewhere that the front brakes on the Hybrid were an upgrade from the 12.5" on the gas MDX to 13" on the Hybrid. Trying to find that reference now....
Highly unlikely as its 17" wheel rated.
Its still the same 12.5" rotor size but just a different design which obviously changes the part number.
 

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Regenerative braking captures kinetic energy that would otherwise be lost to heating up the brake rotors, and uses the energy to charge the hybrid battery. This accounts for most of the improved efficiency of the hybrid drivetrain. It is how the fuel economy can be similar in city stop and go driving and steady-state highway driving. The different brake feel during braking is part of the package. The friction brakes will kick in when necessary.

Sorry to belabor what may be obvious, but if you upgrade the friction brakes and shift the relative amount of energy going into friction loss vs the hybrid system, you will probably reduce the efficiency of the hybrid. And since AWD is exclusively driven from the hybrid battery, you might not have AWD when you want it. Dunno if the hybrid can charge the battery exclusively from the gas engine, but that would affect performance as well as efficiency. As the saying goes, no such thing as a free lunch.
 

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Make sure you give the OEM brakes a chance. It takes some time to get used to the different brakes on a different vehicle. It could be that the brakes on the MDX are fine (I think they are mine) but just feel different to you than what you're used to. This is especially true when comparing across vehicle types - truck, SUV, coupe/sedan, sports car, etc., and even more so with a different type of braking system such as regenerative brakes.

Outside of the feel, it seems that the hybrid's brake pads/rotors would last considerably longer than a non-hybrid due to the additional braking the regenerative function provides.

I certainly wouldn't try to switch them out at this point.
 
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