Ruf RGT-8...live from Geneva!
#32
03-07-2010, 06:50 AM
Ferraris v8's are 180 degree flat plane cranks. So expect this Porsche to sound similar.
#33
03-07-2010, 07:20 AM
Strange designation of 180 deg flatplane V8 confuses me. 180 deg V8 is a flat8 or boxer8. That layout of the cylinders ensures a low center of gravity for the crankshaft (heaviest piece of the engine), hence the 911 boxer6 is a 180 deg V6. The photos show a V8 but their designation of 180 deg is for the "flatplane"? Anyone knows what the designation used means?
#34
03-07-2010, 11:29 AM
http://www.autozine.org/technical_sc...ne/smooth4.htm
However, the disadvantage of cross-plane V8s is also about the counter weights - not only increase the weight of engine, they also contribute to rotational inertia, thus making the engine less responsive and less revvy, dropping upper rev limit and top-end power. Moreover, the larger counter weights usually requires a larger crankcase to house them, thus raising the height (and more important, center of gravity) of the enigne. Therefore Ferrari all V8 models, TVR Cerbera AJP V8 and Lotus Esprit V8 employ flat-plane V8s instead.
Flat-plane V8 is named according to the shape of the crankshaft, which is in a flat plane. It is very much like two inline-4 engines mated together. In particular, it achieves end-to-end balance because the first piston and last piston of a bank is exactly in the same position, so are the center two pistons. This is just the same as straight-four engines, therefore the sound of flat-plane V8 is usually somewhat like a pair of four-pot engines screaming simultaneously, unlike the rumble-bumble of cross-plane V8s.
As both banks run like an inline-4 engine, there is second-order vibration. For a 90° flat-plane V8, the sum of second-order force generated in the 2 banks is - by simple vector analysis - 1.41 times (root-2) of the force generated by each of the inline-4 it consists of. And the direction of vibration is left-right instead of top-down. In other words, while displacement increases 100% compare with the inline-4, the second-order vibration increases just 41%. That makes the flat-plane V8 more refined than an inline-4 although it is not as smooth and quiet as cross-plane V8.
To exotic sports cars, less refinement is not a big problem. Especially they usually employ short stroke and light weight pistons / con-rods, the second-order vibration is greatly reduced.
However, the disadvantage of cross-plane V8s is also about the counter weights - not only increase the weight of engine, they also contribute to rotational inertia, thus making the engine less responsive and less revvy, dropping upper rev limit and top-end power. Moreover, the larger counter weights usually requires a larger crankcase to house them, thus raising the height (and more important, center of gravity) of the enigne. Therefore Ferrari all V8 models, TVR Cerbera AJP V8 and Lotus Esprit V8 employ flat-plane V8s instead.
Flat-plane V8 is named according to the shape of the crankshaft, which is in a flat plane. It is very much like two inline-4 engines mated together. In particular, it achieves end-to-end balance because the first piston and last piston of a bank is exactly in the same position, so are the center two pistons. This is just the same as straight-four engines, therefore the sound of flat-plane V8 is usually somewhat like a pair of four-pot engines screaming simultaneously, unlike the rumble-bumble of cross-plane V8s. As both banks run like an inline-4 engine, there is second-order vibration. For a 90° flat-plane V8, the sum of second-order force generated in the 2 banks is - by simple vector analysis - 1.41 times (root-2) of the force generated by each of the inline-4 it consists of. And the direction of vibration is left-right instead of top-down. In other words, while displacement increases 100% compare with the inline-4, the second-order vibration increases just 41%. That makes the flat-plane V8 more refined than an inline-4 although it is not as smooth and quiet as cross-plane V8.
To exotic sports cars, less refinement is not a big problem. Especially they usually employ short stroke and light weight pistons / con-rods, the second-order vibration is greatly reduced.
#36
03-07-2010, 07:18 PM
This engine was developed in house by RUF and is not based off any current Porsche engine.
More info here: http://www.motortrend.com/auto_shows...t_8/index.html
More info here: http://www.motortrend.com/auto_shows...t_8/index.html
what's not to love
Oh almost forgot "DRY SUMP" lube can be mounted lower (center gravity) with new transmission design
only hiccup >$300K
#37
03-07-2010, 07:22 PM
makes a "shreik" exhaust note (ala Ferrari)
#38
03-08-2010, 04:50 AM
v8's and Porsches!
V8's and Porsches, two of my favourite things. Wow what a feat, the guys from RUF have managed to shoe-horn a 4.5L V8 into the back of a 911!!!! Only thing they could do to top this is to help my gf pack her belongings into 1 suitcase for a 1 week vacation.
Would love to hear this!
Would love to hear this!
#39
03-08-2010, 07:08 AM
Simply Amazing
This technology has been out for a while now with the GM V8s. Too bad it's priced where only very few people could afford it. Now all Porsche AG needs to do is buy this car, reverse engineer it and sell it cheaper. Amazing car though.
#40
03-08-2010, 06:51 PM
V8's and Porsches, two of my favourite things. Wow what a feat, the guys from RUF have managed to shoe-horn a 4.5L V8 into the back of a 911!!!! Only thing they could do to top this is to help my gf pack her belongings into 1 suitcase for a 1 week vacation.
Would love to hear this!
Would love to hear this!
