4 replies to this topic

[cjpani]

I´m not much of an engine conoisseur, but I think I can handle the "basics".

My question is:
how does the angle of degrees of any given engine can affect on the performance of the car??

Is there a direct relation between degrees and performance?

is there a formula for obtaining the best degree of the engine?

Hope you can help out.
Best regards,
cjpani

[desmo]

The included angle of the banks on a V-type engine has virtually no direct influence on it's output. It does however have ramifications that can indirectly affect the performance such as intake and exhaust packaging, vibration and balance issues, C of M, and how the engine fits into the car itself.

[Rene]

To add to what desmo said, a high angled V should allow for a lower center of gravity for the car...hence its desirability

[marion5drsn]

The formula for the "Best"? angle is for four stroke engines "720 degrees divided by the number of cylinders." V-10 engines are therefore 720 degrees divided by 10 is 72 degrees.There are other ramifications to this as are you planning on using 10 primary counterweights etc. etc. The 72 degree angle gets rid of the Secondary shake but there are others things to consider and torsional vibrations the biggest that I know of. Ordinarily torsionals don't destroy an engine as fast as the Primary or the Secondary Shake but they can still be destructive. M.L. Anderson

[Top Fuel F1]

Originally posted by desmo
david_martin is exactly right when he warns that the relationship between included bank angle and vibration is not a simple function. The harmonic vibration that F1 engineers lose the most sleep over are torsional vibrations(TVs) in the crank. These can and have "killed" F1 engines. The wide-angle of the Renault engine may be an attempt to address crank TVs. One F1 engineer said on the subject, "The move to weird bank angles is as a result of attempts to nulify TVs and as an offshoot get some form of "Big Bang" traction benefits ~ all this coupled to the aero package of course."

The "Big Bang" aspect deserves further exploration! I am told that the firing order within the banks has been established as 1-2-4-5-3, not coincidentally the same as a humble Audi 5 cylinder sedan! The tricky part is the cross-bank relationship of the FOs. "Big Bang" essentially refers to the cross-bank FO being such that both cylinders that share a crank throw fire on the same crankshaft rotation- the included bank angle defines the degrees of crank angle seperating the firing events. Or perhaps he simply refers to the changing of firing intervals that result from widening the bank angle. Anyone care to speculate how this could provide "traction benefits"? Could the theories that have driven GP motorcycles to adopt this sort of idea- essentially giving a more tire-friendly tractive input- apply to a 10 cylinder engine?

Seems we have concurrent discussions going on, on the same subject.

Rgds;