New Defender News

soflorovers

Well-known member
Buy the smaller engine or swap the brakes and 18’s will go on. Frankly I’d just buy the smaller engine.
Assuming the remainder of the drivetrain is the same, then sure. I had the chance to drive a P400 this weekend. While the P400 was sufficiently quick, I wouldn't sacrifice 100 HP if I was planning on running anything larger than a 33" tire. Furthermore, I have some concerns Re: undisclosed drivetrain differences between the P300 and P400. In the past, LR has used bigger axles and sturdier drivetrain components on vehicles with more powerful powerplants (makes sense - RRS SC and LR3 HD pack had thicker rear axles for example). So, with that said, if the P400 comes with thicker axles, it just might be worth it to upgrade.
 

soflorovers

Well-known member
Llc8 - 18" wont fit even with heavy spacers. 19" selection sucks so you are forced to 20" which is low profile. Argh.
"Low profile" is a relative term, especially if it's a 20" wheel with a 35" inch tire ;). If that combo doesn't provide you with adequate sidewall, then nothing will.
 

Carson G

Well-known member
Assuming the remainder of the drivetrain is the same, then sure. I had the chance to drive a P400 this weekend. While the P400 was sufficiently quick, I wouldn't sacrifice 100 HP if I was planning on running anything larger than a 33" tire. Furthermore, I have some concerns Re: undisclosed drivetrain differences between the P300 and P400. In the past, LR has used bigger axles and sturdier drivetrain components on vehicles with more powerful powerplants (makes sense - RRS SC and LR3 HD pack had thicker rear axles for example). So, with that said, if the P400 comes with thicker axles, it just might be worth it to upgrade.
Not sure on the axles but the P300 does have 4.11 gears. The P400 has 3.55’s.
 

Carson G

Well-known member
Excuse the n00b question, but what difference does that make?

Sent from my G8441 using Tapatalk
Simply put the P300 has shorter gears to help make up for the 100hp disadvantage. It makes the engine not have to work as hard to move the vehicle you do loose a little fuel economy and some top speed though. It might also give it a better crawl ratio but I’d have to check on that.
 

ChasingOurTrunks

Well-known member
Excuse the n00b question, but what difference does that make?

Sent from my G8441 using Tapatalk

I don’t think this is at all a ”Noob” question as a lot of experienced travellers probably aren’t totally aware of the gearing of their vehicle. And, many who are aware don’t necessarily have a fulsome understanding of why gear ratios are important.

Carson G already answered you succinctly; If you want a longer answer/explanation here you go; I am not an expert and I’m just drawing on what I’ve experienced and learned over the years. If wiser people can jump in and correct me I’m 100% happy for that as it helps my learning too. What it really boils down to is how much power is getting to the wheels for a given speed; for slow off-road driving we want as much power — the ability to move the weight of the car — as possible, being delivered to the rear wheels at a speed that is appropriate for the conditions (Maintains forward movement without losing traction).

Assumptions:

1) First, we’re going to totally ignore transmissions. All a transmission does is add more ratios. The principles below still apply with the transmission in the equation, but changing ratios in a trans is not something I’ve heard of as common, where as changing ratios in a rear diff is very common and the focus of this discussion, so I’ll stick with that. Realistically, every time the engine turns once, the transmission turns a certain number of times depending on what gear you are in, which is translated to the rear diff that turns a certain number of times depending on it’s gearing, which finally gets put to the wheels to turn a certain number of times. Change any of the components here (wheel size, trans gear, diff gearing, or engine revolutions), and the wheels turn more or less, depending on the change you make. Turning wheels is what this is really all about, so let’s use a simple example of an engine connected directly to a diff, which is connected directly to the wheels, with no transmission.

2) For the sake of making things easy, I won’t use exact numbers from LR. let’s just say our vehicle is 5,000 lbs. In this example we are really lucky actually and we have two IDENTICAL defenders — same weight,shape, colour, and even the same motor. The only difference between the vehicles is one of them is a 300 HP motor with a ratio of 4:1 in the rear differential, and another 300 HP engine in a vehicle with 3.5:1 gearing.

Power and Engines:

The power to move the vehicle obviously comes from the motor, but it’s not static — it’s on a curve; as a motor gets more fuel, it puts out more power. At very low RPMs, there is very little power produced. At really high RPMs, there might be a ton of power being made, but it is probably not very efficient because as engines spin faster and faster, they start to ease off on the extra power produced — Between these points is referred to as the “Power Band” of a given motor, and when it’s graphed it looks like a curve. The curves usually look like this:

D7C94E83-EA52-4873-A274-D63B7DEED75A.gif


When people talk about HP and Torque, they are usually talking about “Peak” HP and ”Peak” torque, not torque or HP all along this power band, because as you can see from the graph, it varies depending on RPM. This is one of the reasons why Diesel engines are so popular off road — they hit “Peak” torque at very low RPMs, and tend to produce a lot more torque for a given displacement, which makes them good in slow, off road environments.

Why is it good? Well imagine you are approaching an obstacle and need to move your 5,000 lbs hulk of a rig up and over a rock. Moving 5000 lbs is not easy — it takes energy. So the goal is to put as much energy from the engine to the wheels, but at as low of a speed as possible/reasonable — the wheels turning is ultimately what moves the vehicle forward, but if they try to do that too quickly, the tire spins and you lose traction.

Gear Ratios:

Let’s say we have a 300 HP engine, connected to our wheels via a rear differential with a 4:1 ratio. In this example, with this ratio, if the 300 HP engine turns 4000 times, the rear wheels will turn 1000 times (4:1). Additionally, let’s say you have a tire with a 5 foot circumference, it means every time your tire makes one full rotation, your car moves forward 5 feet. With this ratio of 4:1, it means that at 4000 Engine revolutions per minute, your tires are rotating 1,000 times in that same minute, and that means your car is moving forward at 5000 feet per minute.

Our second car is identical — The exact same engine and all — but this second Defender has a 3.5 to 1 ratio. That would mean that for every 3500 rotations of the engine, the wheels rotate 1000 times. This means that you can run your engine at 3500 RPM, a full 500 RPM less than your buddy with the 4:1 ratio, and still move forward at 5000 feet per minute, although you are now 500 RPM lower - and if “peak” torque is at, say, 5,000 RPM, you are further away from that power peak than your buddy weigh the 4:1 gears.

What does this mean? It means that on highways, the guy with the 3.5 to 1 ratio is a bit happier - he’s using less fuel for a given distance, after all. The engine rotating 3500 times uses less fuel than the same engine rotating 4000 times for the same distance.

Now I’ll introduce one more assumption here — let’s say this engine produces ‘peak’ HP and torque at 5,000 RPM.

After some highway, our defenders are now on the trails. Now it’s our friend in the 4:1 ratio vehicle is the one grinning. This is because when he’s off-road, his gear ratio allows him to more effectively use the engine — he revs at 4000 RPM to move 5000 feet in one minute, which is much closer to the 5000 RPM “Peak” number for this particular motor. His buddy revs at 3500 RPM to move 5000 feet per minute, but he’s further away from ‘peak’ power and torque — For him to get closer to that peak RPM number, he would have to rev his engine much more, and that means he’d have to travel across the ground faster. So, While 4:1 dude is getting 85% of his engine power by travelling at 5000 feet per minute, 3.5:1 dude might only be getting to use 60% of his total engine power for the same speed. And maybe, to move this 5,000 lbs vehicle up over an obstacle, 60% of the engine’s power just isn’t enough. That means that the guy with the 3.5:1 ratio will have to increased his RPMs to get closer to that 85% peak number, which means he’ll be travelling at a higher speed. Off road, not only is this not always possible - it’s quite dangerous in some situations.

Returning to our base assumption — of an otherwise identical pair of 5000 lbs vehicles. But this time, let’s put a bigger 400 HP motor in the 3.5:1 ratio car, while keeping the 4:1 ratio car With the 300 HP motor. How does this play out?

If both cars are at the same obstacle, the “peak” HP and Torque don’t really matter — instead, the minimum HP and Torque required to move 5,000 LBS is what matters. For ease of illustration, let’s say that the motor needs to produce 100 HP and 100 Ft-lbs to get our 5,000 lbs vehicle over an obstacle in it’s way. The big motor may hit that 100 HP and 100 Ft-Lbs number at only 25% of it’s capacity — say, 2000 RPM. The smaller motor would have to rev higher to hit that same 100 HP and 100 Ft-Lbs number — it may need 50% of it’s capacity to hit that number, so let’s say 3,000 RPM.

Bringing this back to gear ratios, Imagine yourself in the drivers seat on a typical off-road trail when you look at these numbers — remember, terrain is usually what limits speed off-road. Take an obstacle too fast and you’ll break something or lose control; take it too slow and you won’t get over the obstacle at all; the goal is to hit that 100 HP and 100 Ft-Lbs of energy at an appropriate speed for off-road driving.

EngineGear RatioEngine Revolutions Per Minute (RPM)Distance Travelled per Minute
300 HP3.5:13,000 RPM4300 Feet
300 HP4:13,000 RPM3,750 Feet
400 HP3.5:12,000 RPM2800 Feet
400 HP4:12,000 RPM2500 Feet


The smaller motor needs to work harder to reach that same 100 HP/Ft-Lbs as the bigger motor, but if they didn’t adjust the gearing, the smaller motor would be covering a lot more ground than the bigger motor, and that’s really the core of the issue - how much ground is covered for a given RPM, which means at a given RPM the wheel is turning faster. A faster turning wheel is hard to place, reduces mechanical sympathy from the driver, and increases the risk of losing traction.

By providing the smaller motor with wider gears (4.xxx:1) and the bigger motor with closer gears (3.xxx:1), it’s getting as much useful power — the ability to move the weight of the car — delivered to the wheels at a speed that is appropriate for the conditions we are driving in to preserve traction and forward movement.

Thank you for reading my gear ratio thesis. I hope I explained it well but if I’ve misunderstood anything (Again, not an expert) I welcome the feedback.
 
Last edited:

DieselRanger

Well-known member
Assuming the remainder of the drivetrain is the same, then sure. I had the chance to drive a P400 this weekend. While the P400 was sufficiently quick, I wouldn't sacrifice 100 HP if I was planning on running anything larger than a 33" tire. Furthermore, I have some concerns Re: undisclosed drivetrain differences between the P300 and P400. In the past, LR has used bigger axles and sturdier drivetrain components on vehicles with more powerful powerplants (makes sense - RRS SC and LR3 HD pack had thicker rear axles for example). So, with that said, if the P400 comes with thicker axles, it just might be worth it to upgrade.
What if they engineered the axles for the P400 and for production efficiency put them in the P300?
 

DieselRanger

Well-known member
I don’t think this is at all a ”Noob” question as a lot of experienced travellers probably aren’t totally aware of the gearing of their vehicle. And, many who are aware don’t necessarily have a fulsome understanding of why gear ratios are important.

...

Thank you for reading my gear ratio thesis. I hope I explained it well but if I’ve misunderstood anything (Again, not an expert) I welcome the feedback.
Awesome.

I'll say that I believe the transmission is the same ZF 8HP transmission that's used on the D5, RRS, and FFRR. Don't know if there are different variants for the Defender as that's a big product line that's used on vehicles with over 600hp. And everything is computer controlled and programmable so shift points may not be the same between, say, the RRS HST (same P400 MHEV setup) and the Defender P400. They may also tune it differently between the P300 and P400.

And, I have to say, this is a great basis for the argument that turbo diesels are best for offroading. More torque/power at lower RPM where most offroading happens, and you get into the power band in low range much easier.

But, between the P300 and P400, the description above doesn't imply that the P300 won't be good for offroading, the P400 will just be a more relaxed engine while doing it. At least until the battery needs to go into regeneration.
 

Corgi_express

Well-known member
But, between the P300 and P400, the description above doesn't imply that the P300 won't be good for offroading, the P400 will just be a more relaxed engine while doing it. At least until the battery needs to go into regeneration.

I'm really excited to hear more news about the plug-in hybrid. I've seen mixed reviews of PHEV on other Land Rover models, but I hope that JLR will optimize for mountains of torque when they release the PHEV. Here's hoping for a announcement soon.
 

ChasingOurTrunks

Well-known member
Awesome.

I'll say that I believe the transmission is the same ZF 8HP transmission that's used on the D5, RRS, and FFRR. Don't know if there are different variants for the Defender as that's a big product line that's used on vehicles with over 600hp. And everything is computer controlled and programmable so shift points may not be the same between, say, the RRS HST (same P400 MHEV setup) and the Defender P400. They may also tune it differently between the P300 and P400.

And, I have to say, this is a great basis for the argument that turbo diesels are best for offroading. More torque/power at lower RPM where most offroading happens, and you get into the power band in low range much easier.

But, between the P300 and P400, the description above doesn't imply that the P300 won't be good for offroading, the P400 will just be a more relaxed engine while doing it. At least until the battery needs to go into regeneration.

Totally agree with you. I would expect them to be mapped differently from comparable motors in other LR vehicles and the mapping really makes a huge impact on how a car “feels” to drive on road. I think either engine will be good off road (and early reviews support that); maybe not the same but both adequate. I wish we could get a diesel option in NA because the platform really does lend itself to an efficient oil burner but if I were to buy one tomorrow I’d actually get the smaller engine — it’s a tad simpler, and I want steel wheels which I don’t think are available on the bigger motor version that requires the 19” wheels.

But most of my overlanding for the past decade has been in 3.6L Jeeps — not exactly known for “stick you to the seat” power — and for highways, I really prefer the power in my Canyon. Off road, so far the gearing has not made a significant difference in experience as the power delivery is pretty responsible. I would expect a similar experience with the Defenders (of course, I won’t know for sure till I drive them!) — hopefully not a significant difference off pavement for most people for either motor, but a bit of a benefit at highway speeds for the bigger power plant.
 

JackW

Explorer
When I drove the P300 on Monday it had plenty of power (and a nice little growl under acceleration) and was very relaxed and quiet at highway speed (80 mph). I don't know how it will do ticking along just above idle in second gear low range like my 300 Tdi does so very well. A diesel is just so outstanding for crawling along a trail at very slow speed allowing you to concentrate on picking the right line.

We reordered my 110 today after having to decline the one that came in this past weekend. Somehow the Tow Pack which includes the Advanced Off Road Capability Pack was deleted from my build and that option can not be retrofitted. I tow trailers and not having the tow package was a deal killer. So now I have to wait another four months for my new truck.
 
Good to see a lot happened since I was gone this weekend on a bit of a California and tad of Nevada crawl. @JackW great to see your beautiful P300 and maybe you can answer some further questions on the driveline when you take it in the garage and get underneath to oooohhhhhh and ahhhhhhhh at her!

My 4.4 is a heavy pig (Sorry Victory) but loaded correctly and driven properly she is more than enough on any trail I've needed. I average 15.3mpg at roughly 70mph on cruise for most of my road driving and around 12mph or less on the trails; depending on what gearbox I was in off course. I spend the majority in Drive on the freeways/cruise and sport-shift between 2-4 gear in Hi-Range on the trails and/or down mountain roads with engine braking/speed control. On the trail if I am in low-range, generally I am in 2-3 gear only with the mighty 1st being for steep incline/declines and rock crawling; Victory crawls up just about anything I ask her too and I think the 4cyl power line is going to do just fine if not overloaded like many of have done or many of us continually do. I learn every time I go out and found in my younger years I limited my vehicle by overloading it regardless of what I drove and now I am conscious about it with planning and my trips are fantastic. Point is, sling what you bring and know your gear for its strengths and weaknesses and plan accordingly and get out and have fun and tread lightly.

I too will wait most likely for the 4 banger in a year or two or maybe pray for a diesel option when I am out of Cali for the extra communist taxation; I mean socialism; I mean democratic socialism; I really have no what or who is running this mess or clue where my taxes go these days to be honest but a D400 is an easy $100k in this money-pit of a state once out the door. Regardless I think the P300 is going to be awesome for many, epic for some, just right for many, and not enough for others but its still a Defender and we have options for P300 or P400 lineup so I hope it continues to hurt the feelings of the negative Nancies around here.

On that note, great to see @ChasingOurTrunks come over here with tons of Jeep experience and lay down some productive conversation........seriously, it is truly welcomed to have other OEM users any brand, class, or experience and bring constructive conversation to the table here in the LR rooms so we have viable and accurate opinion and fact.

Waiting on our lovely Moderators to move all of those other garbage posts from the same broken record crew to the other thread..........early Christmas please???
 

Forum statistics

Threads
185,540
Messages
2,875,670
Members
224,922
Latest member
Randy Towles
Top