Volumetric Efficiency of the 55
04-22-2009, 09:11 PM
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GL450
Volumetric Efficiency of the 55
I did some thinking today about the Volumetric Efficiency of the N/A 55 motor. It's a handmade V8, 5.4L, and it gets about 350 hp. That's really not a lot. Don't get me wrong, it's a great car, great driving motor, etc. But really, that horsepower level from a custom, hand built, motorsport division motor in a $70k car, it's a little underwhelming.
The 5.4L makes 65 hp per liter
The 6.2L makes 83 hp per liter in the SL63
The 1.8L Honda Civic makes 77 hp per liter
The 4.3L Ferrari F430 makes 112 hp per liter
I threw that last one in just to show that none of the Mercedes motors are really a feat of VE engineering, despite being somewhat expensive and rare motors. Even the mundane econobox Civic has better VE than the 55. The 63 motor, however, is definitely a lot better in the VE department than the 55. If the 55 motor made 83 hp per liter, like the 63 series, it would make 448 hp. That would be a nice bump.
It seems that after adding headers, intake, tune, and all the other bolt-on stuff (i.e. still N/A), you can get the 55 to 400 hp. Still 50 hp short of where it's big brother can get (and that's without headers et al).
Can anyone explain the limitations here? And more importantly, is there any way to improve this, or is it really a design limitation of the engine?
The 5.4L makes 65 hp per liter
The 6.2L makes 83 hp per liter in the SL63
The 1.8L Honda Civic makes 77 hp per liter
The 4.3L Ferrari F430 makes 112 hp per liter
I threw that last one in just to show that none of the Mercedes motors are really a feat of VE engineering, despite being somewhat expensive and rare motors. Even the mundane econobox Civic has better VE than the 55. The 63 motor, however, is definitely a lot better in the VE department than the 55. If the 55 motor made 83 hp per liter, like the 63 series, it would make 448 hp. That would be a nice bump.
It seems that after adding headers, intake, tune, and all the other bolt-on stuff (i.e. still N/A), you can get the 55 to 400 hp. Still 50 hp short of where it's big brother can get (and that's without headers et al).
Can anyone explain the limitations here? And more importantly, is there any way to improve this, or is it really a design limitation of the engine?
04-22-2009, 10:59 PM
#2
Absolutly!! Yes! someone here pay attention to the numbers! 
Well, yes the M113 engines have a big design limitations, one of the most important is the SOHC (one cam per head) "the newest M273 DOHC (Dual cam) result in 380hp in the 5.0 "E500"!! poor design in our engines
.. the second is the stock exhaust manifold is very restrictive for 5.5 lts!, valve diameter, camshaft lifts are not the best & others.. any way Mercedes never have the 100% volumetric efficience cause mercedes want their engines are DURABLE! you understand that the maximum peformance in one engine not evolve the max life/duration on it..
Anyway i agree with you!! the bmw M3 E36 Euro 3.2 1999 (same year +/-) have the 3.2 engine with 321 hp!! 100% volumetric efectivity "NORMALLY ASPIRATED" & i think is a very strong engine with a big life time.. i think mercedes AMG can request more power for this engines.. The E55 W211 "SUPERCHARGED" not arrive the 100% of their effectivity i do not understand that!!!!!! this 5.5 may have 550 Hp's "ARE A SUPERCHARED ENGINE, & NO GET THE 100% volumetric eff."
But... No worry man! our cars kick a....!!!
Fabio Daniel
Well, yes the M113 engines have a big design limitations, one of the most important is the SOHC (one cam per head) "the newest M273 DOHC (Dual cam) result in 380hp in the 5.0 "E500"!! poor design in our engines
.. the second is the stock exhaust manifold is very restrictive for 5.5 lts!, valve diameter, camshaft lifts are not the best & others.. any way Mercedes never have the 100% volumetric efficience cause mercedes want their engines are DURABLE! you understand that the maximum peformance in one engine not evolve the max life/duration on it..Anyway i agree with you!! the bmw M3 E36 Euro 3.2 1999 (same year +/-) have the 3.2 engine with 321 hp!! 100% volumetric efectivity "NORMALLY ASPIRATED" & i think is a very strong engine with a big life time.. i think mercedes AMG can request more power for this engines.. The E55 W211 "SUPERCHARGED" not arrive the 100% of their effectivity
i do not understand that!!!!!! this 5.5 may have 550 Hp's "ARE A SUPERCHARED ENGINE, & NO GET THE 100% volumetric eff."But... No worry man! our cars kick a....!!!
Fabio Daniel
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04-25-2009, 06:53 PM
#8
to add to the mix: Lexus GS400 1998 engine 4.0 v8 produces 300hp and 325trq thats 75hp/lit
so at 5.4 a Lexus V8 engine will be around 405hp with 5.4lt
so at 5.4 a Lexus V8 engine will be around 405hp with 5.4lt
Last edited by amgalex; 04-25-2009 at 06:59 PM.
04-25-2009, 07:38 PM
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04-25-2009, 07:43 PM
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04-26-2009, 11:08 AM
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The 5.4L makes 72 lbs-ft per liter
The 6.2L makes 75 lbs-ft per liter in the SL63
The 1.8L Honda Civic makes 71 lbs-ft per liter
The 4.3L Ferrari F430 makes 79 lbs-ft per liter
As you can see, the 55 makes decent torque, but fails to translate that into higher horsepower. I can think of two reasons, since hp is a direct function of torque. The engine doesn't rev high enough (valve train limits redline) and/or the engine produces torque too low in the rev range (runs out of breath up high).
Fabio, it sounds like you're saying it's a little of both. The SOHC probably limits redline, while the small valves would limit high rev breathing. Is it possible to swap a 500 head onto the 55? I thought I'd read that it would fit, but I'm curious if anyone's tried it.
Jon, good point regarding compression. I assume the low compression is why you can bolt a supercharger on and run decent boost, without having to change engine internals. That's nice, but I'd rather have higher compression and n/a power out of the box.
The 6.2L makes 75 lbs-ft per liter in the SL63
The 1.8L Honda Civic makes 71 lbs-ft per liter
The 4.3L Ferrari F430 makes 79 lbs-ft per liter
As you can see, the 55 makes decent torque, but fails to translate that into higher horsepower. I can think of two reasons, since hp is a direct function of torque. The engine doesn't rev high enough (valve train limits redline) and/or the engine produces torque too low in the rev range (runs out of breath up high).
Fabio, it sounds like you're saying it's a little of both. The SOHC probably limits redline, while the small valves would limit high rev breathing. Is it possible to swap a 500 head onto the 55? I thought I'd read that it would fit, but I'm curious if anyone's tried it.
Jon, good point regarding compression. I assume the low compression is why you can bolt a supercharger on and run decent boost, without having to change engine internals. That's nice, but I'd rather have higher compression and n/a power out of the box.
Last edited by saintz; 04-26-2009 at 11:12 AM.
04-26-2009, 11:14 PM
#12
The 5.4L makes 72 lbs-ft per liter
The 6.2L makes 75 lbs-ft per liter in the SL63
The 1.8L Honda Civic makes 71 lbs-ft per liter
The 4.3L Ferrari F430 makes 79 lbs-ft per liter
As you can see, the 55 makes decent torque, but fails to translate that into higher horsepower. I can think of two reasons, since hp is a direct function of torque. The engine doesn't rev high enough (valve train limits redline) and/or the engine produces torque too low in the rev range (runs out of breath up high).
Fabio, it sounds like you're saying it's a little of both. The SOHC probably limits redline, while the small valves would limit high rev breathing. Is it possible to swap a 500 head onto the 55? I thought I'd read that it would fit, but I'm curious if anyone's tried it.
Jon, good point regarding compression. I assume the low compression is why you can bolt a supercharger on and run decent boost, without having to change engine internals. That's nice, but I'd rather have higher compression and n/a power out of the box.
The 6.2L makes 75 lbs-ft per liter in the SL63
The 1.8L Honda Civic makes 71 lbs-ft per liter
The 4.3L Ferrari F430 makes 79 lbs-ft per liter
As you can see, the 55 makes decent torque, but fails to translate that into higher horsepower. I can think of two reasons, since hp is a direct function of torque. The engine doesn't rev high enough (valve train limits redline) and/or the engine produces torque too low in the rev range (runs out of breath up high).
Fabio, it sounds like you're saying it's a little of both. The SOHC probably limits redline, while the small valves would limit high rev breathing. Is it possible to swap a 500 head onto the 55? I thought I'd read that it would fit, but I'm curious if anyone's tried it.
Jon, good point regarding compression. I assume the low compression is why you can bolt a supercharger on and run decent boost, without having to change engine internals. That's nice, but I'd rather have higher compression and n/a power out of the box.
Fabio Daniel
