Mercedes AMG V8 - Naturally aspirated vs Twin Turbo

What's best? The venerable Mercedes AMG 6.2-litre V8, or the new 5.5-litre biturbo V8? World record drifter and Autocar special correspondent, Mauro Calo, tests the Mercedes C63 AMG and SL63 AMG back-to-back on track to find out.

 

Well, of course AMG are looking for continual improvement, so I guess their "new" engines should be better...otherwise why would they produce them.
I LOVE the "classic" 6.3 in our C63...I love the capacity, I love the sound, & I love the performance, its "character" etc etc etc,.....so I'm very happy.
However, when one looks at the performance of the new 5.5TT engine, particularly with the P.P., I don't think there's any doubt that the new T.T. engine is better....it's more powerful, & at the same time it's supposed to be more fuel efficient?
It's probably lighter as well?...so that should improve handling.
Cheers, Pickles.

 

The new 5.5 twin turbo becomes a monster when you add a tune and downpipes for it. Add some intakes, intercooler, and put in high flow cats or delete them all together you should have a 700-800 hp car that gets mid 20 something mpg on the freeway if driven conservatively. But I wonder how bad the turbo lag really is or maybe it's not even noticeable.

In terms of the old 6.3 V8, there's no replacement for displacement still.

 

Turbo lag, how about acceleration lag on the 6.2 V8 NA. Thre is no comparison.

 

karl how much faster is yoiur cls vs your E

 

0 to 60, 3.4 vs 3.9 sec

 

What a GREAT POST.

It cracks me up to see people talking about turbo lag in these factory TT'd cars. These arent T88 Supras folks.

There is simply no reason to not turbocharge - extremely efficient, gobs of power on tap and easily increased, so on and so forth.

 

Quite true. In a modern engine, with direct injection, and variable-vane turbochargers, et al, you get virtually zero turbo-lag anywhere. And the overall torque curve is pretty flat....gobs of low-end power, gobs of mid-range power, and gobs of high-RPM power. Some of the new TT motors are just stunning in terms of what they're able to produce, power-wise, while still being 'relatively' fuel efficient (a car with 500+ HP is only ever going to be so-so in terms of fuel efficiency).

The ONE reason, and one reason only to stick with a naturally aspirated motor is for the sound. The flat-crank V8 in a Ferrari, the high-revving V12 in an Aston Martin, and the V8 in a C63 all have distinct sounds to them. Mercedes has done a reasonable job in maintaining some sound from the new 5.5L TT V8, but BMW missed the boat completely with theirs.

Honestly, I keep waiting for this "Golden Age of Horsepower" to come to an end, but it just keeps on going. When a family sedan can be had with 450+ HP and luxury SUVs are pushing 500+ HP.....it's a good time to be a petrol-head.

Heck, even so called 'cheap' cars like Nissan Altima's etc are putting out 270+ HP, and plenty of modern, small-displacement V6s are putting out north of 300 HP. And getting 30+ MPG.

So I'm going to head out, and burn some hydrocarbons.



Patrick

 

+10000000

 

Sums it up.

 

You have a point about the sound of a NA engine, but the main reason people feel "there's no substitute for cubic inches" is because of the smooth, linear power delivery. Even the best turbo engines still have some lag and the power delivery drops off up top much quicker than a well designed NA engine.

.

 

have either of you heard it in person?

they didnt miss the boat trust me.

its just as loud, IF NOT LOUDER under acceleration than the amg 5.5. and im referring to the exhaust, not the active sound.

 

Daddyo,
You are out to lunch. I have a c63 with Akropovic exhaust and a CLS 63 tuned deleted resonators, sounds great. Sound is BS if it does not translate to real power.

 

Yep have heard, just doesn't float my boat as much as AMG sounds that is all.

 

In times past, I would have agreed with you, and I've had several force-fed and naturally aspirated cars in my time. I drove both the E63 (with 5.5TT) and the new M5 (wife was buying an X6....the dealership let me take out the new M5 while she was shopping for her X6) this year. And there was NO throttle response issue with either car. I've had a WRX STi, and a 944 Turbo, and a Buick Grand National...and all three of those had throttle response lag. Heck, even my Range Rover with a supercharger has some throttle response lag. But both the M5 and the E63 were immediate in the delivery of power. If either of those cars has turbo-lag, it would take a far, far, far more sensitive foot than mine to tell. Press the throttle and go. No response issues at all.


I'm going to completely disagree with you. Yes, I've driven the M5, and it barely burbles at idle. And I didn't find it terribly loud outside either, with driver and passenger windows down at WOT. Certainly nowhere near as loud as my C63 is.

And realistically, if BMW has to playback digital audio of an engine INTO the cabin while driving? Come on....I'm the biggest BMW fan in the world, and they've missed the boat with that move.

I still love the M5 and it's an incredibly capable car. But honestly, if I was after a 4-door executive sedan, I'd probably choose the E63 over the M5. And as I said, I'm a huge BMW fan. Neither car really fits my specific requirements (no need for 4-doors, so I'm sticking with coupes).

One other reason to stick with a naturally aspirated motor vs force-fed.....off-warranty durability. The 6.2L (even with DP) in the C63 should be about as reliable as a wood-burning stove. With the new M5 or E63, I do have some questions as to how reliable those turbo-charged engines will be over the long term.



Patrick

 

Patrick -

I love turbo-charged motors. I've owned a heavily modified 1.8T GTI and a 335i that was stock in the past. I've also test driven most of the new turbo performance cars. Compared to a NA motor, the throttle response is still not the same - despite the DBW throttle lag some have described. That affects both types of motors.

I will say that the new turbo cars do not lag as much as the aforementioned Supra or anything with a huge turbo that needs big revs to spool and has the on-off feel due to a number of reasons. That being said, throttle is not as crisp.

 

I've spent some time in the V8 TT's, and at my elevation (3700ft) you can feel the turbo lag. It's way more powerful than the 6.2L V8 though, which only makes 420 real hp at this elevation. If you keep the revs up above 3000rpms in the turbo motors, however, it all goes away. That rpm range is probably lower at sea level (closer to 2000?).

 

Not sure what you're talking about.
I was comparing and contrasting an NA engine vs. a FA engine.

.

 

Also let's not forget that AMGs 5.5 biturbo still has 5.5 liter of displacement. This is such a big engine for the size of it's turbos compare to an average turbo engine that has a noticeable lag.

 

Forced induction motors can put out more HP/TQ with less displacement than an N/A. The downside is some peakyness to the power curve and alot more components that can go wrong. Tweaked forced induction motors produce globs of power, however the design of the MBZ turbos integrated into the exhaust manifold does make it more difficult to tweak the turbos themselves. Of couse the aftermarket will respond quickly with even more power producing turbos inside a modified exhaust manifold. All you guys that like long tube headers are out of luck.

 

Having owned on many na and turbo cars, I will say that I felt NO noticeable turbo lag in my extensive test drives of a 2012 E63 PP car. It was monsterous power. And of course part of the allure is the flat torque car. I really believe to my butt, that was the fastest car I have ever driven. Even felt faster than the stock 997 tt I have driven in past.

"Grand Natiional".... ha! Had not heard about that car in awhile, nice to see it mentioned in this thread

 

+1 finally someone drove one.

 

"Grand National"....That was a Buick wasn't it...with a S/C V6?....an N/A version of that engine was used in our Aussie Commodores for years.
Cheers, Pickles.

 

Turbo 3.8 V6 IIRC.

 

Yes, turbo-charged, 3.8V6. Something like 245 HP, and 355+ lb-ft of torque.

If you want to talk turbo-lag....that car defined it. It was also a great wallowing bath-tub of warm water to drive as well....sloshed around everywhere, with cloth Lazy Boy chairs for seats, and a suspension made out of fresh Ju-Jubes.

But at the time they were sharp-looking, in that 80s sense. And I loved having the T-Tops, which is really something you don't see on a car anymore.

I've always been a corner-carver and not a drag-strip kind of guy, so while I enjoyed the GN while I had it....I switched to a BMW not long after.

It might have been worth it to keep as a collector's item (I only had something like 3,000 miles on it when I sold it). But I prefer to drive my cars, and not just park them to look at them. To me, if a car isn't at least suitable as a daily-driver, then I'm not terribly interested.

Cars are meant to be driven, not parked.



Pat