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What makes a Maserati GranTurismo loud?

4K views 10 replies 9 participants last post by  pcray1231 
#1 ·
So A Maserati Grand turismo, 2008, has a 4.5 L v8 engine. BUT a 2010 Jeep Grand Cherokee Laredo has a 5.7L V8. Why is the Maserati faster, AND louder than the jeep? Is it the exhaust? ALSO, I don't know much about cars…..so Im just wondering, thanks!
 
#4 ·
You are comparing a finely-tuned Italian racing engine to a Dodge engine and wonder why there is a power-difference?

Most of the difference is in engine design, materials and tuning. (tuning includes taking advantage of the exhaust pulses to scavenge the cylinders.)

The "loudness" of an exhaust has very little to do with "power". However, many young drivers think it does. They believe that stickers and a grocery-cart handle on the back of their car make it go faster too.

I always enjoy going to the drag-races on "street car day"... many of those same youngsters find out that their cars are nothing more than noise-makers. My buddy with a 4-cylinder Dodge Rampage with Maserati heads (which is not very loud) can spank the noisemakers who have twice the engine.
 
#5 ·
Often the fastest cars are the quietest cars..in car guy speak those cars are known as "sleepers". These drivers know what they have and don't advertise it.
Loudness appreciation has a lot to do with engine design. V12 and V8's tend have pleasing sounds, V6 and I4's tend to have annoying sounds. All very subjective of course. Since this is a Subaru forum, some think the flat 4 has a pleasing sound. I am former Porsche 911 owner and the flat 6 had a very pleasing sound in my opinion.
And then there's the "Phallus Principle" in engine noise. Some owners of loud vehicles, motorcycles included, use engine noise as a form of compensation for their erectile dysfunction. You might hear and see this in revving Harley Davidsons with straight exhaust.
 
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#6 ·
Yeah, the sound has a lot to do with the engine, but also the exhaust configuration.

You gave displacement numbers and # of cylinders. A whole lot more goes into engine power than just displacement. For instance, adding turbochargers do not substantially increase displacement, but they do add HP. # of valves, timing, type of injection, etc. all play a part And running at higher RPM. Higher RPM's require engine balance and more exact timing and better injection methods, but they effectively increase the displacement. Your cylinders are the same size but you are firing pistons that many times more, hence pumping more gas and air through the engine.

As far as how powerful the engine is, as a rating, forget displacement and cylinders, give me HP and torque of those engines at various rpms. The whole curve would be nice but stand-in numbers are fine to make the point.

As for how fast it'll accelerate, you need two more things. The first is the transmission - this controls getting that power to the wheels. More gears are nice, but if it's an automatic, how it's programmed means a lot, as well as response time. Plus, what are the gear ratios? The second is the curb weight - how heavy of an object do we have to get moving here?

And for top speed - a lot has to do with suspension, weight balance, center of gravity, etc. If the car can safely handle the higher speeds, then you can run higher rpm's and give it a gear ratio to keep on accelerating till you get there.

It's quite possible for one car to accelerate very fast, another to reach a higher top speed, another win on a track with any sort of curve, and yet another would win the same race if all vehicles were required to, say, tow a boat. :)

More applicable numbers:

2008 Granturismo:
405 hp
339 lb-ft
Redline: 7250 rpm
Curb weight: 4150 lbs
Tranny: 6 spd auto.
0-60 time: 5.1 seconds
Top speed: 177 mph

2010 Jeep Grand Cherokee Laredo:
347 net HP
383 lb-ft
Redline: 5400 rpm
Curb weight: 4795 lbs
Tranny: 5 spd auto
0-60 time: 6.8 seconds
Top speed: 129 mph

So, the Mazerati, which isn't all that powerful by sports car standards, still generates more HP on a significantly lighter vehicle by running at a higher rpm, on a tranny with more gears and presumably, gear ratios designed for acceleration and speed, with better aerodynamics, and a suspension and weight balance designed for a track. Hence better acceleration and top speed.

The Jeep, on the other hand, comparatively has lower HP but actually higher torque, likely with lower gearing, to presumably have a MUCH higher tow rating. But the lower rpm's, gearing, with off roadish suspension and aerodynamics comparable to a sailboat, means it's not as fast.

To be sure, it's interesting that you picked a sports car on the "standard touring" side of it's genre's spectrum, and an SUV on the "sporty" side of it's. Take a sportier sports car and a more laid back SUV and the differences would be the same, just much more severe.
 
#7 ·
And running at higher RPM. Higher RPM's require engine balance and more exact timing and better injection methods, but they effectively increase the displacement.
Not sure what you mean by "effectively", but there's 2 ways to actually increase displacement and that's increase the bore or the stroke and of course number of cylinders.

Engine Cubic Inch/CC Displacement Calculator
 
#8 ·
#9 ·
Don't feed the troll.
 
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#10 ·
a moderator could just toss the troll and the thread.

.....

or we could use it as yet another location to post questions about the universe.

I think I will buy a 2012 dodge pickup off a dealer today, ....so FCA will buy it off me expecting to make money.
 
#11 ·
Not sure what you mean by "effectively", but there's 2 ways to actually increase displacement and that's increase the bore or the stroke and of course number of cylinders.
I mean that, no, you haven't increased displacement.

But yes, you are running higher rpm's with the same displacement, and thus pumping more gas and air through the engine, resulting in more power. "Effectively" because actually increasing displacement (via increasing bore or stroke or more cylinders) would also pump more gas and air through the engine, resulting in more power.

In the end, how much gas and air you use tells you how much energy the engine can theoretically make. Increasing displacement, and increasing rpm's both go after increasing that number.

I realize efficiency comes in as well, but even assuming equal efficiency, it's not as straightforward as saying a 5.7L 8 cylinder can generate more power than a 4.5L 8 cylinder engine. If the 4.5L engine runs at higher rpm's, it can burn more fuel and generate more energy.

Then you get into efficiency of the engine, efficiency of the rest of the car, and power to weight ratios. All of which the Mazarati will win again.
 
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