Rx400h Torque & Horsepower Curves

[Gryphon]

Has anyone found horsepower and torque curves for the RX400h? (Actually two sets for FWD and AWD.)

Tom

[RX400h]

Are you referring to that which is generated by a dyno? I haven;t seen anything, yet.

[NeoN]

Are you referring to that which is generated by a dyno? I haven;t seen anything, yet.

after 20k miles and breaking in my RX i wanna dyno mine. I've only got 750 miles so its going to be a while :)

[Jim Clark]

The hybrid system may not react well to a 4 wheel dyno. With the rears only being driven be the electric motor, if it shuts off during the run and the fronts continue to speed up, the car's computer(s) will likely go bonkers. You need to bring the dyno slowly up to speed before you punch it for the actual run. You would have to be able to punch it from the start to ensure the rear electric motor stays engaged and I don't know if you can do that, I'm pretty sure you can not.

It's possible our AWD cars can not be dyno'd. FWD could be done.

[Gryphon]

Are you referring to that which is generated by a dyno? I haven;t seen anything, yet.

Yes, I guess so. Or from a magazine test, which I have not seen yet. I seem to remember (but can't find) someone posting a combined max torque number over 700, which surely cannot be correct.

Tom

[Jim Clark]

Are you referring to that which is generated by a dyno? I haven;t seen anything, yet.

Yes, I guess so. Or from a magazine test, which I have not seen yet. I seem to remember (but can't find) someone posting a combined max torque number over 700, which surely cannot be correct.

Tom

Our electric motors are "torquey" but they ain't THAT torquey, LOL.

[williz]

Has anyone found horsepower and torque curves for the RX400h? (Actually two sets for FWD and AWD.)

Tom

the RX400h is having a maximum combined torque of 750Nm and 200kw (272PS)

max torque ICE = 288Nm

front e-motor = 333Nm

rear e-motor = 130Nm

(all lexus figures and diagrams)

rear e- motor

rear_e_motor.pdf

front e-motor

front_e_motor.pdf

ICE

ICE.pdf

[NeoN]

Has anyone found horsepower and torque curves for the RX400h? (Actually two sets for FWD and AWD.)

Tom

the RX400h is having a maximum combined torque of 750Nm and 200kw (272PS)

max torque ICE = 288Nm

front e-motor = 333Nm

rear e-motor = 130Nm

(all lexus figures and diagrams)

rear e- motor

rear_e_motor.pdf

front e-motor

front_e_motor.pdf

ICE

ICE.pdf

can you please convert NM into lb/ft?

[riwyle]

One Newton-meter = .737 pound- foot

Has anyone found horsepower and torque curves for the RX400h? (Actually two sets for FWD and AWD.)

Tom

the RX400h is having a maximum combined torque of 750Nm and 200kw (272PS)

max torque ICE = 288Nm

front e-motor = 333Nm

rear e-motor = 130Nm

(all lexus figures and diagrams)

rear e- motor

rear_e_motor.pdf

front e-motor

front_e_motor.pdf

ICE

ICE.pdf

can you please convert NM into lb/ft?

[RX400h]

The hybrid system may not react well to a 4 wheel dyno. With the rears only being driven be the electric motor, if it shuts off during the run and the fronts continue to speed up, the car's computer(s) will likely go bonkers. You need to bring the dyno slowly up to speed before you punch it for the actual run. You would have to be able to punch it from the start to ensure the rear electric motor stays engaged and I don't know if you can do that, I'm pretty sure you can not.

It's possible our AWD cars can not be dyno'd. FWD could be done.

From a 2005 issue of Car & Driver:

At the rear wheels we find the rear electric motor (MGR), which is hooked directly by gear drive to the rear differential. This one is air- and oil-cooled, since it only functions intermittently (the other MGs are water- and oil-cooled), and it adds another 67 horsepower to the mix. Hermance says this motor cranks over 650 pound-feet of drive-axle torque to the vehicle’s overall tractive effort when it’s energized.

We believe him. Nail the RX400h’s throttle from rest, and you might hear front or rear tires chirping, depending on available grip. The V-6 growls with the usual determination when you’re hard on the gas, but the continuously variable transmission pegs its rotational speed somewhere near the torque peak and maximum volumetric efficiency, producing sound effects that are the opposite of a slipping clutch. Instead of a rising engine note as vehicle speed remains constant, the vehicle speed rises as the engine speed remains constant.

[Jim Clark]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

[mindmachine]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque. :whistles:

[Jim Clark]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque. :whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

[mindmachine]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque. :whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

Well you would have to take that up with NeoN it's his data i am only telling you the data he posted is equal to 553 ft-lbs of torque, no as an engineer myself, I must say you have to consider how the torque is applied and how the computer allocates the power for the Toyota hybrid system. for example just look at the GS450h vs the Rx400h. It depends on how the computer program is designed to apply the torque and how much is possible from all three sources at once. The programming of the system for power,acceleration and performance, or more reasonable performance and better fuel economy. It is entirely possible that the way the system is engineered that the full 553 ft-lbs is never available all at once, actually I would be willing to bet a sizeable sum of money on that point. It's not a Porsche Cayenne Hybrid geared toward performance primarily, it's a Lexus Scorer Mom/Dad type vehicle and probably programmed accordingly!!!!!!

:chairshot:

I have to say and thankfully so, I have a Porsche Cayenne S and I bought my Lexus RX400h for the decent fuel economy and decent performance it gives in an SUV size vehicle. 4365 lbs curb weight, 4 wheel drive version!!!!

I have to say 6.9 sec 1/4 mile aint bad considering you can get 26 to 30 mpg highway, my Cayenne S only gets 16 to 18mpg highway and doesn't perform that much better in the 1/4 mile!!!!! The 2006 Porsche Cayenne Turbo S only does 5.9 sec 1/4 mile what do you want?

[RX400h]

Actually, Car & Driver recently clocked the RX400h's 0-60 MPH in 6.7 seconds. They mentioned that this time is better than that of a Porsche Cayenne-S.

Of course, this kind of speed is dependent upon premium fuel and a fully-charged battery, but still, for the superior gas mileage it gets, compared to any other luxury SUV, the RX400h is among the fastest, even at 4600 lbs!

[Jim Clark]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque. :whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

Well you would have to take that up with NeoN it's his data i am only telling you the data he posted is equal to 553 ft-lbs of torque, no as an engineer myself, I must say you have to consider how the torque is applied and how the computer allocates the power for the Toyota hybrid system. for example just look at the GS450h vs the Rx400h. It depends on how the computer program is designed to apply the torque and how much is possible from all three sources at once. The programming of the system for power,acceleration and performance, or more reasonable performance and better fuel economy. It is entirely possible that the way the system is engineered that the full 553 ft-lbs is never available all at once, actually I would be willing to bet a sizeable sum of money on that point. It's not a Porsche Cayenne Hybrid geared toward performance primarily, it's a Lexus Scorer Mom/Dad type vehicle and probably programmed accordingly!!!!!!

:chairshot:

I have to say and thankfully so, I have a Porsche Cayenne S and I bought my Lexus RX400h for the decent fuel economy and decent performance it gives in an SUV size vehicle. 4365 lbs curb weight, 4 wheel drive version!!!!

I have to say 6.9 sec 1/4 mile aint bad considering you can get 26 to 30 mpg highway, my Cayenne S only gets 16 to 18mpg highway and doesn't perform that much better in the 1/4 mile!!!!! The 2006 Porsche Cayenne Turbo S only does 5.9 sec 1/4 mile what do you want?

You're saying the hybrid system is "capable" of 550+ ft lbs but we'll never get to use it? 7 sec 1/4 mile? :whistles: Now THAT's impressive ;) I know what you meant.

I guarantee the maximum torque at the wheels is less than 300 ft lbs, probably closer to 250. IF our cars can be dyno'd, and I still don't think they can because the hybrid system will go crazy and shut down, it would show that.

[RX400h]

Remember, electric motor torque peaks at 0 RPM, so you can't really compare that torque number to say, the torque that is generated solely by an ICE-engine. We can probably trounce any SUV to 20 MPH, due to our exposive low-end torque. The 1/4-mile drag race is another story, but hey, what is more valuable during our day-to-day commutes? I'll take low-end torque, any day!

[Jim Clark]

Remember, electric motor torque peaks at 0 RPM, so you can't really compare that torque number to say, the torque that is generated solely by an ICE-engine. We can probably trounce any SUV to 20 MPH, due to our exposive low-end torque. The 1/4-mile drag race is another story, but hey, what is more valuable during our day-to-day commutes? I'll take low-end torque, any day!

I agree about preferring low-end torque. When you punch our cars and get all 3 motors working, the power is impressive. But if they were producing 550 ft lbs at the wheels we'd be doing about 4.5 sec 0-60 times.

[Gryphon]

Has anyone found horsepower and torque curves for the RX400h? (Actually two sets for FWD and AWD.)

Tom

the RX400h is having a maximum combined torque of 750Nm and 200kw (272PS)

max torque ICE = 288Nm

front e-motor = 333Nm

rear e-motor = 130Nm

(all lexus figures and diagrams)

rear e- motor

rear_e_motor.pdf

front e-motor

front_e_motor.pdf

ICE

ICE.pdf

Does anyone have software to digitize these curves so that they can be converted to different units and/or combined?

Tom

[Jim Clark]

I guess I need to be smokin whatever you guys are putting in your pipes.

[mindmachine]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque.:whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

Well you would have to take that up with NeoN it's his data i am only telling you the data he posted is equal to 553 ft-lbs of torque, no as an engineer myself, I must say you have to consider how the torque is applied and how the computer allocates the power for the Toyota hybrid system. for example just look at the GS450h vs the Rx400h. It depends on how the computer program is designed to apply the torque and how much is possible from all three sources at once. The programming of the system for power,acceleration and performance, or more reasonable performance and better fuel economy. It is entirely possible that the way the system is engineered that the full 553 ft-lbs is never available all at once, actually I would be willing to bet a sizeable sum of money on that point. It's not a Porsche Cayenne Hybrid geared toward performance primarily, it's a Lexus Scorer Mom/Dad type vehicle and probably programmed accordingly!!!!!!

:chairshot:

I have to say and thankfully so, I have a Porsche Cayenne S and I bought my Lexus RX400h for the decent fuel economy and decent performance it gives in an SUV size vehicle. 4365 lbs curb weight, 4 wheel drive version!!!!

I have to say 6.9 sec 1/4 mile aint bad considering you can get 26 to 30 mpg highway, my Cayenne S only gets 16 to 18mpg highway and doesn't perform that much better in the 1/4 mile!!!!! The 2006 Porsche Cayenne Turbo S only does 5.9 sec 1/4 mile what do you want?

You're saying the hybrid system is "capable" of 550+ ft lbs but we'll never get to use it? 7 sec 1/4 mile?:whistles: Now THAT's impressive ;) I know what you meant.

I guarantee the maximum torque at the wheels is less than 300 ft lbs, probably closer to 250. IF our cars can be dyno'd, and I still don't think they can because the hybrid system will go crazy and shut down, it would show that.

What i am saying is the maximum torque of all three added together, the two electric motors and the ICE is 553 ft-lbs of torque, however that does not say that the hybrid system programming allows the combined use of all the torque at once. Nor does it imply even that the maximum torque is even available from all three sources at the same RPM and therefore not available as maximum torque (at the tires) at the same time or road speed. Bottom line is the maximum torque of all three is 553 ft-lbs, but the programming of the hybrid system I am convinced regulates and limits how much can be applied (combined) at once.

For example I seriously doubt the the front electric motor and the ICE produce their maximum torque at the same output level RPM wise. I also doubt that applying the maximum torque to the front wheels would even be advisable from a mechanical point of view. I doubt the CVT is designed to handle it all at once. If you add the front motor and the ICE, the therotical front end maximum torque is 458 ft-lbs, if you applied all of this at once the torque steer effect would be a bigger complaint by owners than what it currently is.

Anyway just my 2 cents worth, while I am a retired mechanical engineer I am not an automotive engineer. My expertise is large jet engines and pipeline compressors, so I am used to fluid torque. I do know however that applying torque mechanically you have to design the hardware to handle the maximum output you plan on applying plus a safety factor. Well in my opinion the Lexus RX is not designed to be a street racer and therefore not designed to apply all 458 or 553 ft-lbs of torque all at once. The key being the front drive mechanism where in theory 458 ft-lbs is available for use.

[Jim Clark]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque.:whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

Well you would have to take that up with NeoN it's his data i am only telling you the data he posted is equal to 553 ft-lbs of torque, no as an engineer myself, I must say you have to consider how the torque is applied and how the computer allocates the power for the Toyota hybrid system. for example just look at the GS450h vs the Rx400h. It depends on how the computer program is designed to apply the torque and how much is possible from all three sources at once. The programming of the system for power,acceleration and performance, or more reasonable performance and better fuel economy. It is entirely possible that the way the system is engineered that the full 553 ft-lbs is never available all at once, actually I would be willing to bet a sizeable sum of money on that point. It's not a Porsche Cayenne Hybrid geared toward performance primarily, it's a Lexus Scorer Mom/Dad type vehicle and probably programmed accordingly!!!!!!

:chairshot:

I have to say and thankfully so, I have a Porsche Cayenne S and I bought my Lexus RX400h for the decent fuel economy and decent performance it gives in an SUV size vehicle. 4365 lbs curb weight, 4 wheel drive version!!!!

I have to say 6.9 sec 1/4 mile aint bad considering you can get 26 to 30 mpg highway, my Cayenne S only gets 16 to 18mpg highway and doesn't perform that much better in the 1/4 mile!!!!! The 2006 Porsche Cayenne Turbo S only does 5.9 sec 1/4 mile what do you want?

You're saying the hybrid system is "capable" of 550+ ft lbs but we'll never get to use it? 7 sec 1/4 mile?:whistles: Now THAT's impressive ;) I know what you meant.

I guarantee the maximum torque at the wheels is less than 300 ft lbs, probably closer to 250. IF our cars can be dyno'd, and I still don't think they can because the hybrid system will go crazy and shut down, it would show that.

What i am saying is the maximum torque of all three added together, the two electric motors and the ICE is 553 ft-lbs of torque, however that does not say that the hybrid system programming allows the combined use of all the torque at once. Nor does it imply even that the maximum torque is even available from all three sources at the same RPM and therefore not available as maximum torque (at the tires) at the same time or road speed. Bottom line is the maximum torque of all three is 553 ft-lbs, but the programming of the hybrid system I am convinced regulates and limits how much can be applied (combined) at once.

For example I seriously doubt the the front electric motor and the ICE produce their maximum torque at the same output level RPM wise. I also doubt that applying the maximum torque to the front wheels would even be advisable from a mechanical point of view. I doubt the CVT is designed to handle it all at once. If you add the front motor and the ICE, the therotical front end maximum torque is 458 ft-lbs, if you applied all of this at once the torque steer effect would be a bigger complaint by owners than what it currently is.

Anyway just my 2 cents worth, while I am a retired mechanical engineer I am not an automotive engineer. My expertise is large jet engines and pipeline compressors, so I am used to fluid torque. I do know however that applying torque mechanically you have to design the hardware to handle the maximum output you plan on applying plus a safety factor. Well in my opinion the Lexus RX is not designed to be a street racer and therefore not designed to apply all 458 or 553 ft-lbs of torque all at once. The key being the front drive mechanism where in theory 458 ft-lbs is available for use.

OK, good write-up. BUT, even if the maximum torque was available from all three engines, wouldn't they cancel each other out, at least to a certain extent? This question is from a non-engineer.

The rear electric motor is RARELY used. Even under heavy acceleration from a stop, it shuts off quickly.

I assume the CVT is only used by the two front engines. When you floor it, the kilowatt gauge gets pegged and I assume the CVT in conjunction with the computer(s) regulates the RPM of the ICE and the front electric motor. What regulates the rear engine?

I guess what I'm asking is: "HOW DOES THIS DARN THING ACTUALLY WORK?"

[mindmachine]

OK, I must be a complete idiot.

BUT, wouldn't a vehicle with 600-700 ft lbs of torque (at the wheels) be WAY WAY faster than our 400h's?

What am I missing?

First that isn't ft-lbs.. it' newton-meters and the conversion factor is like .7375622 I believe. However this is why the wheels on the RX 350 aren't suited to the RX400h.

So 751 newton meters equals 552.55 ft-lbs of torque.:whistles:

550 ft lbs of torque should give you whiplash. Our 400h's have a good amount of power but I don't see how anyone can claim they have 550 ft lbs of torque.

I won't believe it until I see some credible evidence. The best evidence I have so far is driving the car. There is NO WAY our cars have 500+ ft lbs of torque.

Well you would have to take that up with NeoN it's his data i am only telling you the data he posted is equal to 553 ft-lbs of torque, no as an engineer myself, I must say you have to consider how the torque is applied and how the computer allocates the power for the Toyota hybrid system. for example just look at the GS450h vs the Rx400h. It depends on how the computer program is designed to apply the torque and how much is possible from all three sources at once. The programming of the system for power,acceleration and performance, or more reasonable performance and better fuel economy. It is entirely possible that the way the system is engineered that the full 553 ft-lbs is never available all at once, actually I would be willing to bet a sizeable sum of money on that point. It's not a Porsche Cayenne Hybrid geared toward performance primarily, it's a Lexus Scorer Mom/Dad type vehicle and probably programmed accordingly!!!!!!

:chairshot:

I have to say and thankfully so, I have a Porsche Cayenne S and I bought my Lexus RX400h for the decent fuel economy and decent performance it gives in an SUV size vehicle. 4365 lbs curb weight, 4 wheel drive version!!!!

I have to say 6.9 sec 1/4 mile aint bad considering you can get 26 to 30 mpg highway, my Cayenne S only gets 16 to 18mpg highway and doesn't perform that much better in the 1/4 mile!!!!! The 2006 Porsche Cayenne Turbo S only does 5.9 sec 1/4 mile what do you want?

You're saying the hybrid system is "capable" of 550+ ft lbs but we'll never get to use it? 7 sec 1/4 mile?:whistles: Now THAT's impressive ;) I know what you meant.

I guarantee the maximum torque at the wheels is less than 300 ft lbs, probably closer to 250. IF our cars can be dyno'd, and I still don't think they can because the hybrid system will go crazy and shut down, it would show that.

What i am saying is the maximum torque of all three added together, the two electric motors and the ICE is 553 ft-lbs of torque, however that does not say that the hybrid system programming allows the combined use of all the torque at once. Nor does it imply even that the maximum torque is even available from all three sources at the same RPM and therefore not available as maximum torque (at the tires) at the same time or road speed. Bottom line is the maximum torque of all three is 553 ft-lbs, but the programming of the hybrid system I am convinced regulates and limits how much can be applied (combined) at once.

For example I seriously doubt the the front electric motor and the ICE produce their maximum torque at the same output level RPM wise. I also doubt that applying the maximum torque to the front wheels would even be advisable from a mechanical point of view. I doubt the CVT is designed to handle it all at once. If you add the front motor and the ICE, the therotical front end maximum torque is 458 ft-lbs, if you applied all of this at once the torque steer effect would be a bigger complaint by owners than what it currently is.

Anyway just my 2 cents worth, while I am a retired mechanical engineer I am not an automotive engineer. My expertise is large jet engines and pipeline compressors, so I am used to fluid torque. I do know however that applying torque mechanically you have to design the hardware to handle the maximum output you plan on applying plus a safety factor. Well in my opinion the Lexus RX is not designed to be a street racer and therefore not designed to apply all 458 or 553 ft-lbs of torque all at once. The key being the front drive mechanism where in theory 458 ft-lbs is available for use.

OK, good write-up. BUT, even if the maximum torque was available from all three engines, wouldn't they cancel each other out, at least to a certain extent? This question is from a non-engineer.

The rear electric motor is RARELY used. Even under heavy acceleration from a stop, it shuts off quickly.

I assume the CVT is only used by the two front engines. When you floor it, the kilowatt gauge gets pegged and I assume the CVT in conjunction with the computer(s) regulates the RPM of the ICE and the front electric motor. What regulates the rear engine?

I guess what I'm asking is: "HOW DOES THIS DARN THING ACTUALLY WORK?"

Well not being a Toyota Engineer I don't have any way of knowing what algorithms they used to program the Hybrid Drive System. Once again as I said in the last three posts on this, it depends on how the system is programmed. The programming no doubt monitors many factors I am sure, like current speed, throttle position, current state of battery charge, probably outside temperature, current state of traction of the VDIM, and probably many other factors. It then takes the various factors into account and then allocates the power from each of the three sources according to the algorithms used in the performance program and design criteria.

[skyfish400h]

Dyno predict

By working backward from reported data we can use physics to predict what torque and horsepower to expect on the dyno (provided the 400h will perform on a dyno).

conversions courtesy of convert.exe from http://joshmadison.com/software/convert/

Given==

Given Quantities in metric [uS] units:

mass (m) = 1980 kg [4365 lbs]

0-60 time (t) = 7.3 s

speed (v) = 26.8 m/s [60 mph]

tire radius (d) = .356 m [14 in]

Reference values in metric [uS] units:

ref system power = 200 kW [268 hp]

ref ICE torque = 288 Nm [212 ft-lbs]

ref Fwd torque = 333 Nm [246 ft-lbs]

ref Rear torque = 130 Nm [96 ft-lbs]

ref Total torque = 751 Nm [554 ft-lbs]

Physics==

Impulse (J)

J = mv = Ft [eq 1]

where F is the force exerted by the road to propel the 400h

Torque (T)

T = Fd [eq 2]

where d is the distance between the road and the drive shaft of the wheel (tire radius)

Power (P)

P = Fv [eq 3]

Torque Solution==

Solving [1] for F and substituting into [2] leads to the following relation in terms of T

T = mvd/t [eq 4]

T = (1980 kg) (26.8 m/s) (.356 m) / (7.3 s) = 2588 Nm acting thru all 4 wheels

The simple breakdown per wheel is 647 Nm [477 ft-lbs] ea, but due to the greater power to the front wheels the breakdown would more accurately be determined by the following...

Using ref torque values to determine breakdown ratios (ignoring gear ratios)

Ratio Fwd: Front Torque / Total Torque ==> (288 + 333) / 751 = .83

Ratio Rear: Rear Torque / Total Torque ==> 130 / 751 = .17

Apply ratios for front/rear torque distribution to each wheel

2588 (.83)/2 = 1074 Nm [792 ft-lbs] per Front wheel*

2588 (.17)/2 = 220 Nm [162 ft-lbs] per Rear wheel

*This Fwd wheel value highlights the need for very strong rims on the 400h (that is a lot of torque).

Power Solution==

Solving [1] for F again and substituting into [3] leads to the following relation in terms of P

P = mv^2/t [eq 5]

P = (1980 kg) (26.8 m/s)^2 / (7.3 s) = 194,810 Nm/s or Watts moving the 400h mass

Thus 195 kW [261 hp] compares well with the advertised 200 kW [268 hp] reference value.

Apply ratios for front/rear to power distribution

195 (.83) = 162 kW [217 hp] at the Front axel

195 (.17) = 33 kW [44 hp] at the Rear axel

Conclusions==

Clearly the 400h is forward bias in the power delivered to the ground.

It will be interesting to see if these numbers play out if/when someone actually gets the 400h to perform on a dyno.

Fun with numbers==

So what would the 400h be like if we could put one of the hefty fwd electric motors into the rear of the car?

Using ref torque values to determine breakdown ratio

Ratio Fwd Electric: Front Elec Torque / Total Fwd Torque ==> 333 / ( 288 + 333) = .54

Apply ratio for front elec torque distribution to each wheel

1074 (.54) = 580 Nm [428 ft-lbs] per Rear wheel

Now, summing up the new torque from all 4 wheels

2(1074) + 2(580) = 3308 Nm acting thru all 4 wheels

Solving [4] for t

t = mvd/T [eq 6]

t = (1980 kg) (26.8 m/s) (.356 m) / (3308 Nm) = 5.7 s from 0-60 mph mph)

I will leave it to the reader to show that this translates to a 1/4 mi time of 13 s with a top speed of 141 mph (assuming the Lexus 112 mph speed limit feature is defeated).

[RX400h]

Holy cow! I wish I had the time to check your calcs! It must be nice to be retired.....

Thanks for the herculean effort!