NAV8 vs SCV6 Comparison

Looking at specifics for 7000 feet, normal temperature and humidity, Actually
the loss with a naturally aspirated engine will be about 58 hp or 15.4 percent power loss. Forced induction engines will lose approximately 8 percent (27.2 HP) to 10 percent (34 hP) at the same altitude in the same conditions. The issue with forced induction is that the air at higher altitudes is thinner and the same problems that beset the naturally aspirated engines start to befall the FI engines as altitudes rise. Reduce the humidity, increase the temperature and the problem continues to increase. One solution is increasing boost which LR does not give one the option to do out of the gate. If you could increase injector output and sequentially increase boost to compensate for altitude, you theoretically could output close to the same HP as at sea level. (If the engine would stand the strain)

Turbo charging leaves the same issues but to a slightly smaller scale since they are already dealing with intense heat that must be cooled. Both supercharging and turbocharging inter coolers remain somewhat inefficient as elevations rise. Nothing performs like at sea level!

manoftaste said:

So if the general consensus is that a NA engine loses about 3 percent of its power for every 1000 ft of elevation, vs a FI engine that loses only about 1.5 percent (half) for the same 1000 ft, then the SCV6 wins hands down at an elevation of say 7000 ft.

Using the above formula the following will be the final horsepower left for each engine at 7000 ft:

NAV8: 375 hp (at sea level) minus 21 percent of it (78.75 horses) = 296.25 horses
SCV6: 340 hp (at sea level) minus 1.5 percent of it (35.7 horses) = 304.3 horses

And of course the difference would be higher (say at 8000 ft or more) in favor of the SCV6.

So with that math, the range rover (or sport) with its 510 hp SCV8 motor does pretty well at 7000 ft for still having more than 450 horsepower at that elevation.

I wonder whats the loss percentage of torque at elevation.

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Riiiiiiight. Whatever makes you feel better.

This thread is so over.

Honestly, given the minuscule MPG difference, if there was a choice and price would be the same, would folks choose the SCV6 for this vehicle over the V8 since you get better towing...etc. with the latter? I think if the answer is V8 for most, it conveys how people feel about the SCV6 in comparison.

Having said that, there is only one option with new LR4s and I'm sure it's more than capable for 90% of most folks buying this wonderful vehicle.

manoftaste said:

As far as performance on the highway, I felt the same when I moved from my LR3 to LR4 V8 a year and a half ago. I was expecting my LR4 V8 to be a lot more responsive with more gut at highway passing, but that wasn't the case. Honestly, I feel that when I stepped on it in my LR3 at highway speeds, it really pulled with power with a feeling of constant increase in speed, so much so that I would have to ease off on the gas to let it up shift again and calm down a bit.

I remember the only one time I felt that the power wasn't enough on the highway (in my LR3) is when this one night I was driving to vegas on 15 and I was climbing up on a slight grade and wanted to go faster than 90 mph so pressed the pedal a bit more to get more speed and was surprised to find out that there was no more room left under the gas pedal. LR3 was struggling a bit go above 90 mph. I could have been on higher elevation stretch at the time. The car wasn't even fully loaded, it was just me and a carry on and bunch of other usual stuff in the car.

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Wow I couldn't disagree with you more on the LR3 to LR4....especially when towing my 24' boat....

ougrad1 said:

Honestly, given the minuscule MPG difference, if there was a choice and price would be the same, would folks choose the SCV6 for this vehicle over the V8 since you get better towing...etc. with the latter? I think if the answer is V8 for most, it conveys how people feel about the SCV6 in comparison.

Having said that, there is only one option with new LR4s and I'm sure it's more than capable for 90% of most folks buying this wonderful vehicle.

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Honestly, the biggest 'issue', if you can even call it that, with the SCV6 is the throttle mapping. Land Rover has tuned the vehicle to be incredibly lazy off the line thus requiring a fair bit of throttle input (more than you'd expect) before it takes off at a reasonable pace. This tends to give the truck a slow, underpowered, pokey feeling... but it actually does have a fair bit of jam. If you pin it, it actually gets it's fat ass hauling much more quickly than you'd expect. I keep prattling on that with aftermarket tuning, the SCV6 has the ability to surpass the V8 performance numbers by a fair bit.

..mg.. said:

Honestly, the biggest 'issue', if you can even call it that, with the SCV6 is the throttle mapping. Land Rover has tuned the vehicle to be incredibly lazy off the line thus requiring a fair bit of throttle input (more than you'd expect) before it takes off at a reasonable pace. This tends to give the truck a slow, underpowered, pokey feeling... but it actually does have a fair bit of jam. If you pin it, it actually gets it's fat ass hauling much more quickly than you'd expect. I keep prattling on that with aftermarket tuning, the SCV6 has the ability to surpass the V8 performance numbers by a fair bit.

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How so and at what cost?

Don't tell me your going to throw a ton of $ at that v6 and compare it to the stock v8.

What your explaining is the loss of torque on the V6.

Also, since the SCV6 is from jag, I wonder if its been beefed up in terms of seals, water-proofing, belts, steep angles, etc, just the way the V8 was prepped for LR duty when it was originally designed. Unless I have missed it, I have not read anything in that regard in LR press etc the way I had read about the 5.0 V8 when it was first introduced.

brettmess24 said:

How so and at what cost?

Don't tell me your going to throw a ton of $ at that v6 and compare it to the stock v8.

What your explaining is the loss of torque on the V6.

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What I'm explaining is precisely NOT the supposed loss of torque. What I'm explaining is throttle mapping. x% of applied throttle = x% of TB plate opening and resulting IDC, load etc.; the calibration on the SCV6 is such that you need a lot of throttle to get the output you would expect. Ready to have your mind blown? The V6 and the V8 perform the same in the real world. We have an '11 LR4 with the V8, and a '14 SCV6. For fun (remember, these are not performance vehicles), I compared the two side by side. Bench racing, which results in great arguments, is rarely accurate. 0-60 sprints were almost equal, with each vehicle "winning" depending on who got the better jump. Up to highway speeds that I'm comfortable with in a vehicle this size, they're within spitting distance of each other, again depending on who got the better jump. If I was really motivated and cared to waste my money, I'd get both on an AWD dyno to see what the true, non-marketing material, performance comparison was.

Anyway, you'd spend maybe $500 for a flash and $500 more for an undersized pulley to really open things up. So $1,000 all in for a very spicy machine. I would take an FI engine over NA every single time for commuter applications.

The benefit is that this same engine is shared across numerous Jag models (as ↓ mentioned). As it's new, there isn't much in the way of aftermarket tuning yet. Give it a year or two, and we'll see where things are at.

manoftaste said:

Also, since the SCV6 is from jag, I wonder if its been beefed up in terms of seals, water-proofing, belts, steep angles, etc, just the way the V8 was prepped for LR duty when it was originally designed. Unless I have missed it, I have not read anything in that regard in LR press etc the way I had read about the 5.0 V8 when it was first introduced.

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I doubt it. Despite the differential and suspension bells and whistles, the LR4 is a commuter vehicle.

I must be in the minority as I care very much about torque and tow my boat loaded with family. Would be great to compare the two engines/transmission.

Dry weight of boat and trailer is 4900 lbs so loaded up with gas family etc I have to be about 6500lbs.

Deciding if I should hold on to my12. No 8 has me leaning toward a yikes Tundra!

I just vacationed in NH and rented a place that was on a mountain. The LR4 had to do a 650' climb in less than a mile. Up the hill at 2krpm with 750lbs+ worth of people and stuff, no sweat, smooth as silk not a sense of drama or straining.

I doubt the SCV6 would have felt as comfortable.