Who makes the best V8? - Page 4

noncom23 · #31 12-09-2007, 02:36 PM

Quote:

Originally Posted by JCL

Since the Ferrari is in the comparison, how can we compare cross-plane and flat-plane designs in the same article? The cross-plane is smoother, but doesn't have the exhaust note or tuning potential. It also doesn't rev as easily, and is heavier. The flat-plane is bred from a racing engine, and you can't compare the two exhaust notes, they are essentially two different engine designs. It is like comparing Nascar to F1. (bias showing here).

Hate to show my ignorance here, difference between cross and flat plane? Like V vs Horizontal angle on the heads?

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JCL · #32 12-09-2007, 02:51 PM

Quote:

Originally Posted by noncom23

difference between cross and flat plane? Like V vs Horizontal angle on the heads?

Crankshaft design. The first V8s were essentially two four cylinder engines on a common crankshaft. The crankshaft has throws at 180 degrees, hence the flat plane reference. This engine offers the best V8 tuning potential. Balance is an issue, often requiring balance shafts.

The cross plane crankshaft has throws at 90 degrees, with two con rods per throw. You need to add heavy counterweights on the crank, so it doesn't rev as well. However, it offers pretty good balance with those counterweights (not as good as an inline 6, but approaching it). This design of V8 was essentially a compromise, driven by wanting the packaging efficiency of a V8, and trading off several other design goals. An example is that the firing order is not even, which results in the characteristic V8 burble, but also means that exhausts have to be interconnected between banks for tuning. All V8s designed for ultimate performance (Cosworth, Ferrari, etc) will be flatplane designs (quite a generalization there).

The biggest driving differences between the two designs will be exhaust note and how quickly the engine revs.

noncom23 · #33 12-09-2007, 03:00 PM

Ok. Thx J. Learning everyday...

vinuneuro · #34 12-09-2007, 03:21 PM

If you want learn about more about engine geometry read this article:

http://www.autozine.org/technical_sc...ne/smooth1.htm

noncom23 · #35 12-09-2007, 03:28 PM

Quote:

Originally Posted by vinuneuro

If you want learn about more about engine geometry read this article:

http://www.autozine.org/technical_sc...ne/smooth1.htm

Thx Vin, printing it now.

DanDE · #36 12-09-2007, 03:41 PM

Quote:

Originally Posted by LeMansX5

...and don't you have that.

All of it!

Wagner · #37 12-09-2007, 04:04 PM

Quote:

Originally Posted by JCL

Excellent, another engine discussion!

Agree with your comment that it depends on what you're judging. The Corvette has amazing and affordable performance, the Aston has a certain style, and the Ferrari, well, it is a Ferrari.

However, to suggest that GM, which was very late to the V8 party, somehow invented the class, is misleading. Even if you go back to the early Cadillac (which wasn't a GM then), you are a decade or so after the first V8s from France and England. If you talk about the first mass-popular V8 it is Ford with the '32 flathead. That is the engine that made the V8 a part of history. Then 15 years later there was the odd Oldsmobile, etc, but GM didn't really get in there with a historic V8 until the 265 in the mid fifties, admittedly a great engine. It also started out in the Corvette, so it is relevant to the post. That engine has had a great run, with some design features still around in the current GM V8s.

Since the Ferrari is in the comparison, how can we compare cross-plane and flat-plane designs in the same article? The cross-plane is smoother, but doesn't have the exhaust note or tuning potential. It also doesn't rev as easily, and is heavier. The flat-plane is bred from a racing engine, and you can't compare the two exhaust notes, they are essentially two different engine designs. It is like comparing Nascar to F1. (bias showing here).

There was a mention of the Chrysler Hemi. Chrysler only ever built a few real hemi engines starting in the mid '60s. The current ones are a marketing campaign, not a real hemi. 'nuff said.

As cars, my vote goes with the Ferrari. For affordable performance, nothing touches the Corvette. But I still want the Aston in my garage, emotionally.

Isn't it great to live in a time when there are some fantastic cars available? We are definitely spoiled for choice.

SANguru · #38 12-09-2007, 05:05 PM

some common flat crank designs include all the F1 cars, The V10 in the carrera GT, ferrari V8's and of course many of sport race bikes. As other have said, exhaust note and of course less rotation mass making it easier to rev are the keys.

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