95bat

It's mostly displacement and cam profile, not some magic technology. You can have a small motor with mountains of torque, but you lose the top end horsepower. Lexus went more for top end power with their design of a high RPM, high power motor. It isn't really a secret anymore how to do this lol.

Bigger displacement motors can have the best of both worlds. The displacement helps make up for the loss of torque and still get strong top end power. Even going up from our 5 liter to a 6 liter has huge torque benefits. Another bump to a 7 liter and you've got my favorite motor 😁 Google some dyno graphs of the LS3/LT1/LS7 and compare it to ours. They make excellent torque as low as 1800 rpm, but they don't Rev to 7300 rpm either. Just a design choice.

trippleB

I approach the torque and RPM domain from another angle.

The rev limit (redline) of an engine is not the focus. The risk of lower redline will be a problem only if:
- the transmission gear ratios are too aggressive, plus a small size tire which leads to low top speed of the vehicle; or :
- the transmission gear ratios are too conservative, which solves the top speed issue but causes insufficient wheel torque.

Nowadays auto makers are smart enough to design the gear ratios and tire size to be suitable enough, such that the power band of the engine can cover the whole speed range of that vehicle. As long as it can fulfill that requirement, the red line of the engine is irrelevant because it is just a number printed on the tachometer. Unless the driver specifically likes to listen to the sound of the engine at some particular RPM range, the value of the number printed on the meter really does not matter.

It is the torque per liter, and also how flat of the torque curve matter.

Torque per liter measures how well the NA engine inhales air, and how complete the fuel burn to utilize all those available air, and how well of all the energy from the burn make it to the crankshaft to propel the vehicle. These determine by a huge collection of factors which makes perfecting a NA engine to be so hard. High torque per liter means high peak torque (given similar displacement);

The flatness of the torque curve indicates how soon the peak torque arrives, and how well the engine can maintain the peak torque to higher RPM. The flatter the curve means the peak torque is achieved sooner, and can be maintained to very high RPM.

So the higher the torque per liter, and the flatter the torque curve, the better. It worth to call out that, we should compare engine of similar architecture, for example DOHC vs. DOHC, or OHV vs. OHV. This is because the weight of the push rod in OHV engine will cause the rod to vibrate excessively under high RPM, so the red line of an OHV engine is typically lower than DOHC to prevent damage; however the single large intake value of the OHV architecture makes it easy to achieve peak torque at lower RPM. So there are both pros and cons for both architecture.

Let's take a look at how the 2UR-GSE match up with others:

• 2UR-GSE torque per liter is: 79.5 lb-ft/L; it maintains ~81% of the peak torque from 2.5k RPM to red line

Compared to some other NA engine:

• Toyota 2GR-FSE, torque per liter: 81 lb-ft/L, it maintains ~86.6% of the peak torque from 2.5k RPM to red line
• Ford Coyote (pre-2024), torque per liter: 83.4 lb-ft/L, it maintains ~77% of the peak torque from 2.5k RPM to red line
• Dodge 5.7L Eagle HEMI, torque per liter: 72.5 lb-ft/L, it maintains ~90% of the peak torque from 2.5k RPM to red line (this is an OHV engine)

These data are all calculated from factory official document, which means they are the torque curve measured at flywheel. Not all auto maker publishes its engine output curve, these are what I can collect within the hour that I am writing this reply. The reason I did not use dyno numbers is because the data quality cannot be guaranteed and it also mixes other factors such as the transmission.

From the above data, the V8 on the IS500 is somewhat lukewarm when compared to other, but it is OK for its purpose. It obviously still have quite some room to improve - as we can see even thhe V6 2GR from the same factory is remarkably better. OHV engines generally have very flat torque curve, but it exchanges the rev limit with this.

DLPTony

I want to change my answer. God knows this thread has gone on for so long, my initial response has been archived. 😉😂

I spend hundreds of dollars a month at Shell Pump #5, a crap ton of time detailing it in between multiple washes, and weekend after weekend up in the mountains slaying our Mini-Tail of the Dragon (It’s a real thing.) and seriously hanging with Lotus’, Vettes, R32 Skylines, and a gaggle of IS F’s.

So what don’t I like? Nothing. I clearly effing l-o-v-e this car to effing bits!

17.5K miles in 17 months and counting.

Happy.
Effing.
Motoring!

95bat

I typed up a lengthy response, but then I took a Sunday afternoon nap and realized it didn't matter. I don't agree with several parts of your post, but again, doesn't matter. The point of my post was that designing an engine isn't some secret mystery. Lexus chose to build this motor as a more powerful high redline motor at the sacrifice of low end torque (without sacrificing reliability). Lexus could have gotten more torque from the motor, but at the expense of horsepower. You can't have the best of both worlds without a displacement increase, power adder, or a hit to reliability. My point was that Toyota/Lexus knows this, they're not behind on tuning like you originally said.

SpudsMcD

Dude, you are totally off-base here. Redline, or usable range of engine speed is critical to the driving experience. A low redline (e.g., 6K rpm) is just nowhere near as engaging, exciting, or fun as a high redline (e.g., 8.5K rpm), even if the lower-redline engine has better peak torque, or even peak horsepower. The ability to hold second gear through a longer section of curves, i.e., reduced shifting frequency, is unbeatable on track, and way more fun. Even in street driving, the ability to hold gears longer makes for a much more enjoyable drive. The 7300rpm redline on the IS500 is very good for a non-exotic V8, certainly one with Toyota reliability. The only other high-rpm engine you mention is the Ford Coyote (7500 rpm in Dark Horse form), and that's got a host of other problems that Ford appears to have no interest in solving (including an improperly balanced flat-plane crank that causes vibration problems which are going to be hell for durability). The Dodge is a joke at 6200 rpm, and the IS350 is marginally better at 6600 rpm.. My McLaren 12C redlined at 8500 rpm (peak torque was 442 lb-ft. and pretty flat from 1500rpm on up), and the ability to pull second gear to the redline was unreal, shifting into third was at about 80mph. A high redline just makes the car a lot more enjoyable.

trippleB

Let me summarize @95bat and @SpudsMcD 's opinion: Toyota/Lexus sacrificed the low end torque (not-so-flat torque curve), and also the peak torque (lower lb-ft per liter), in exchange for the high rev limit, and also peak hp, on the 2UR-GSE engine.

Please let me know whether the summary is correct, if yes I can provide some fruit for thought; if not please correct my above sentence. Thanks.

04gita

Quick correction here: the vast, vast majority of S550 Mustangs have the "Coyote" bent-crank V8. Only the GT350/GT350R got the "Voodoo" flat-plane crank engine, which has been, to be polite, reliability-challenged. But that [deserved] bad reputation doesn't apply to the regular GT, or Mach 1, or other Mustangs of the generation. Same goes for the new S650, including Dark Horse, which all have the Coyote underhood).

Longwaldo

I came from a 2019 Mustang GT premium PP1 because my car sounded like a typewriter and I had no faith in the engine. It was my second Coyote. 2014 had no issues.

arentz07

Folks, let's keep this in context of the thread topic; we can always create a separate thread about engines if needed.

Side note: OF COURSE THAT IS WHAT THEY DID. It was made to go in the IS F, which was to be a motorsport-inspired high-performance car. What else would they have done?

BChoCRNA

I really wish the IS500 came with power foldable side mirrors like the JDM IS500.

Phresh2010

iTrader: (3)

If this can be retrofitted, I would buy right meowwwwwwwww

TipsyTonio

@nigel821 did it on his RC F but I believe it was $4000 in parts alone and if I’m not mistaken the auto function does not work, only the manual power folding option.

abdrury

Can we talk about the USA 1884 license plate?? He’s got the folding mirrors but we’ve got what he wants: ‘Merica

BChoCRNA

thats a damn shame because the JDM version does have auto folding mirrors





no clue as to why Lexus removed this option for the states.

DLPTony

::heehee:: I would too, but I’ve made my peace with it. So I park so far away it’s not needed, or I’ll do the ghetto-walkaround.