Those are the two reasons I'm familiar with, though I'd add that covers can also help reduce dirt and dust build-up too.

 

Only problem is that when they know they will have a full cover they do nothing to try to make the top of the engine look decent in "naked" form. Compare at Lexus 5 liter to say an LS or Coyote v8, the latter two look much nicer "uncovered", the Lexus is just a snake pit of hoses and wires.

 

same here, i can understand about noise and look. even dust i am not very sure since they come from everywhere. but when you cover the engine bay like that, heat efficiency can hardly be a reason i think. just imagine a car with and without the hood, which one is likely to run cooler?

 

noise and presentation are the only purposes.
I've taken the plastic covers off, and it's dirty as hell under there, because all the dust comes in from the grille and underneath the car.

Also, a car with and without plastic covers runs about equally cool, because the coolant radiator in the front. It's not like heat escapes upward, since the hood is sealed with a gasket all around the engine bay.

 

What do you define lag as? This TTV6 the power will come on very early, how many turbo cars have you owned? I have a single turbo supra does it come on later than when it had stock twins sure but not by much, the average person would not notice the difference on how it comes on, once it hits boost it hits harder than stock twins. I have rolling anti-lag meaning the ECU can "brake boost" for me while I'm rolling. Obviously the LS500 won't have that feature but I'm full aftermarket EMS. I get that you don't like it has a TTV6 instead of the V8 I wished it had a V8 just because but don't post stuff bashing TTV6's because of that, take a ride or drive a bone stock R35 that's a 3.8 TTV6 to understand powerbands of V6TT engines. Yes sequential turbos are better on a Inline 6 than V6 but a V6 spooling in parallel has a very nice powerband it's not waiting to build boost like my single turbo inline 6 does.

 

Plus the ceramic ball bearing turbos of today spool literally instantly, especially is on the smaller side which these will be. I doubt Lexus plans to leave much on the table for turning up the wick, so two very small turbos can easily support under 500hp on a relatively large displacement 6. Why not wait, take a drive in one, and then decide if you need to bash it. The only reason to prefer a v8 would be for the better, deeper exhaust note, but in an LS you want vault-like quiet so that is no longer an issue. I would also hazard to guess this new Lexus v6 will be supremely smooth and thus the reason they waited to introduce it on their flagship rather than a lesser model like a GS or IS-F.

 

The bashing the characteristics of an engine nobody has experienced yet is beyond silly I agree.

 

Correct the newer turbos today are better built than the ones from the Supra OEM era. BB turbos have ridiculous spool like you said and since these will be smaller ones even better. I urge anyone bashing this engine they haven't driven yet to drive a R35 GTR on stock twins sure it's .3L bigger than what the Lexus TTV6 will be but you will be surprised at how it comes on for a "heavy" car. Better yet to check the lag try the 3.0 TTV6 in the Infiniti line Q50 and the coupe would be a good example to try since it would be easier to test drive that versus a R35 GTR.

 

Lag (as defined by the old days of turbo cars) is pretty much non-existent these days in factory turbo setups.

What makes cars lag is when your turbo is larger (hence more inertia) than it needs to be. For example, when people put huge turbos in their cars, it's because they want 800+ hp. Supra guys do it all the time. Is it laggy? Of course. The turbo is oversized to provide the headroom (flow) for 800hp.

A properly matched turbo to a small engine will be imperceptible. If you put a 200hp (worth of flow) turbocharger on a 4 cylinder, it won't be laggy. It will be so small that the response will be more than acceptable. Downside? That engine/turbo combo is only good for 200hp. No more boost for you.

Ever driven a VAG 2.0T? Do you really think that 2-liter 4 cylinder is laggy? Come on. Same goes for the Ecoboost 2.7 and 3.5. Both of those have no lag.

Those turbos sure are screaming, tho! Hahaha you will be changing those sooner than you think.

The V6TT will feel like is has a fat V8 in it. The power delivery will be smooth as silk, I'm sure. The noise is all you will miss.

Plus that fat boy torque curve more than compensates for any millisecond lag you may be worrying about.

 

Good points Jose, I'm one of the Supra guys with what some would consider with a big single BW S366 SX-E. I have friends with 7Xmm and 8Xmm turbos but they are all 10:1 on E85. I drove Ford's Ecoboost 4 cyl and 6cyl and a R35 GTR no lag when compared to my Supra or even my old school GS400 with the 1UZ. I can get around "lag" on my Supra when rolling or even from launch using features of the Infinity 6 EMS.

 

I've driven many modern twin turbos, and lag is non-existent. I suspect the same will hold true with this one. 1st gear transmission hesitation has been something i noticed with high torque engines (manufacturer settings). That is is normal/comfort modes but gone in Sport modes. As long as this engine is quiet, we will be happy driving the torque.

 

I absolutely can feel the lag in a VAG 2.0t, whether that be the new A4 or a MK7 GTI I drove over the holidays. It's not major but I can definitely feel it at lower RPM's.

 

Ok, so your sensitivity for that is very high. By lower RPM's you mean like under 2k rpm, right? I had an MKV GTI and man by 1.5k it was moving nicely, and by 2k, it was GONE. For me, it was more than adequate for that application.

I appreciate your being able to discern that type of lag, but I feel for most of the public, they wouldn't notice. Especially in a car like the LS and it's audience where smooth power delivery (they call that lag) is good.

My mother has an SC430, and I recall reading somewhere that that car was detuned at low RPM on purpose (tuned-in lag) due to complaints of too much power when the pedal was initially pressed? Not sure if that's true, but I will say, I can't drive that car. Might as well be a camry engine in it with how bad it responds.

Point is, in the LS and who it's for, a tiny amount of lag (if any) would barely be perceived by most if not appreciated as "smoother". I wouldn't worry at all in this case.

 

Seriously some of you are completely missing the point of what I was trying to say.

I was talking about turbo types and the ability to help and mitigate lag. Twin-scroll turbos are designed in way to do just that. These turbos are found in BMWs, Porsches, Audis, etc and they do help with lag and part of the reason certain manufacturers use them, albeit they are more expensive.

Traditional single-scroll turbos aren't as capable in this department and, we were merely speculating that this engine has or probably has two single-scroll turbos.

By inference, if you believe twin-scroll turbos are better at combating lag, then by simple transitive property, you can assume that this engine will have more lag, more so then if it had two twin-scroll turbos.

And since no one outside of Lexus has driven it yet, your assertations are as speculative as mine.

 

I think a slow throttle response is often mis-characterized as turbo lag. You'll see people on this forum, with N/A engines talk about the slow throttle response on some cars, especially in the RX forum. On a N/A engine, people say "the throttle is laggy" but if the car has a turbo, they'll say "I feel the turbo lag".

Yes, I do believe some turbos have some lag, most often noticeable in say, a 5mph to 60mph test (rather than 0-60), but the manufacturers have done a tremendous job in greatly reducing that lag to the point that I think most people don't notice.

FWIW and full disclaimer, I've driven but never owned a turbocharged car. I have, however, had a supercharged car. My thoughts above could be all wrong.