2006 2.4 liter v-8 engine only formula

[riff_raff]

"Isnt there anybody that can explain why a V8 generates more vibration than a V10 ? "

For a given displacement, the mass of the individual reciprocating components (conrod, piston, etc.) are less for the V10, and the instantaneous accelerations (and thus inertia forces) are lower due to the shorter stroke dimension with the V10.

[Scuderia_Russ]

Also less strokes per degree of crankshaft turn.

[Guest]

Ahhh thanks!

/ Fx

[Guest Jsmith]

A v8 has more vibration because of the degree of crankshaft rotation until the next cylinder fires. A 10 cylinder engine has a cylinder fire every 36 degrees thus smooths out the idleing and running. a v8 only fires every 45 degrees, and the worst of the engines is probably a 4 cylinder firing only every 90 degrees.. So the more number of cylinders you have the smoother its going to run and theoretically will have better throttle response.

[riff_raff]

Jsmith,

I believe you're mistaken. An even-firing (5 crank pin) 72 deg, 4 stroke V10 fires every 72 degrees of crank rotation, and an even firing (flat crank) 90 deg, 4 stroke V8 fires every 90 degrees of crank rotation.

However, your basic proposition, that a V10 produces less instantaneous torque variation (peak-to-mean) throughout its cycle than an equivalent displacement V8, is still correct.

[Guest]

PMS (pardon my stupidity) Thanks for the clarification Riff, I just thought this by looking at the distributer cap, a circle divided by the 10 cylinders, But i guess the ratio from the cap to the crank shaft would change this.

[Guest: Ash]

I dont care much bout what they do in terms of regulations, as long as there is no restrictions on R&D. witout R&D, the sport would be pretty pointless. I look forward to 2006 and, as in the past, i'm sure these V8 cars will still be even quicker than the previous season's V10's.

[ginsu]

Most of the vibration issues are due to the configuration of the crankshaft.

Crossplane V8's are pretty well balanced, but are heavy and don't rev very high.

Flatplane V8's are not as well balanced but the crankshaft is much lighter so they can be made to rev.

From http://www.autozine.org/technical_schoo ... th4.htm#V8

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.

[Guest]

so the formula v8s use flatplane? could someone explain or link to a site that thoroughtly explains the differences between the two?

[ginsu]

so the formula v8s use flatplane? could someone explain or link to a site that thoroughtly explains the differences between the two?

Yes, F1 engines could not rev very high if they used crossplane crankshafts. Think about the lumbering american v8's. All crossplane, all rev to a max of about 5,500rpm. They may be balanced, but they are not exciting.

If you read my post above, there's a link to a webpage that explains everything, with pictures even!

[jgredline]

To put it simply my guess would be two main things. I have not had a chance to sit down and really think about it, but my guess is this.
1) the crankshaft in a v10 would be symetrical and close to a 4cylinder engine where the counter weights are opposite each other. With the V8 crank this is not possible.
2) The firing order. With a V10 it is very posible and likely to have a firing order that would be 12345678910 (odd numbers on one side and even numbers on the other) With this style of firing order the exhaust header would also follow the same sequentail firing order thus producing less resonence and smoothing out as the RPMS go up.
Like I said I will need to think of it a little bit more, but this would be my quick guess.

[ginsu]

I just read in F1Racing that the V8's will be more unreliable because they spend more of their time at full throttle, approx 10% more than the v10. This could be very significant for circuits like Monza where the v10's already ran at 70% throttle. We could be seeing 80+% around the circuit.

I can't imagine how hard it is to make something reliable that is at 18,000rpm for an hour.

[Guest]

Thats one of the reasons why Mclaren wont win this years championship.

/ Fx

[Guest]

Full throttle does not mean full revs.

[Guest]

Good point!