Ferrari F10

[autogyro]

Alesi will almost certainly win at Monaco and I think I know why.

[segedunum]

Personally, I've hated this engine homologation. It's utterly pointless.

Yes, this is cheating and no it shouldn't have resulted in an increase in power. They've taken a worryingly unreliable engine made, it more relable and added a hefty chunk of horsepower. That's not what engine homologation was for, and yet, this is all somehow OK. I don't like it when people wheel out the anti-Ferrari number. That's no defence here.

[Skinn3r55]

The compression ratio of the engine is the ratio between the volume available in the cylinder when the piston is at BDC and the volume available in the cylinder when the piston is at TDC. Basically the volume of the whole cylinder divided by the volume of the combustion chamber. I think there would be significant changes required to change that.
What I think you meant is that they can increase the pressure in the combustion chamber by delaying the moment at which the intake valve closes, which leads to an increased enthalpy of the air-fuel mixture (if I remember correctly) and consequently better efficiency.

[autogyro]

The compression ratio of the engine is the ratio between the volume available in the cylinder when the piston is at BDC and the volume available in the cylinder when the piston is at TDC. Basically the volume of the whole cylinder divided by the volume of the combustion chamber. I think there would be significant changes required to change that.
What I think you meant is that they can increase the pressure in the combustion chamber by delaying the moment at which the intake valve closes, which leads to an increased enthalpy of the air-fuel mixture (if I remember correctly) and consequently better efficiency.

To achieve any change in valve lift or duration,it would require changes of camshaft or changes to valve mechanism geometry.
If changes occur to lift without this the valve would be bouncing against the cam lobe.
Compression ratio is not the same as cylinder pressure.

[flynfrog]

Wild attempt: the current valves seal the engine better than they used to. Thus, combustion might be more efficient and the compression ratio is increased. This could also allow running a more powerful mix for longer.

Sorry that does not make sense.
There would only be an increase in compression if the lift, duration and closing of the valves was altered. Correct?
But the problem was stated as a pneumatic leak that resulted in an inability to recharge the gas feed bottle.
(gas valve springs only close the valves, nothing else)
This is a system running out of gas, not a change of any sort to the way the valve train operates.
It would aso have nothing whatsoever to do with improved fuel mixture.
Reducing the amount of gas leakage would in fact 'decrease' any excess gas available for valve and general engine cooling, which would result in a less efficient fuel mix because of higher temperature.

Just thought I would re post this as no one has as yet answered it.
Perhaps there is a draft of what was agreed, that explains everything?

maybe they were able to take weight out of the valve train and reduce some losses that way.

Good idea flyn-frog reducing valve mechanism mass would in ordinary circumstances account for an increase in power from increased engine revs. There is a slight problem with this however, the engines are already limited to 18000 rpm and they all reach the limiters anyway.

it would also gain power from less friction on the cam assuming they are running a lower pressure return piston.(not sure what the correct term is on an air system. A nascar v8 losses around 300 hp in the valve train friction. Its not that hard to believe that you couldn't find 15hp from a small change.

[Skinn3r55]

I know compression ratio is not the same as pressure. It's just that someone was posting that the change made to the valves would change the compression ratio and i believe that can't be the case.
Also I didn't mean they would want to change valve lift or duration. Just that having the experience of a few races they might have concluded they could obtain better volumetric efficiency by delaying the intake valve a few degrees.

[autogyro]

I know compression ratio is not the same as pressure. It's just that someone was posting that the change made to the valves would change the compression ratio and i believe that can't be the case.
Also I didn't mean they would want to change valve lift or duration. Just that having the experience of a few races they might have concluded they could obtain better volumetric efficiency by delaying the intake valve a few degrees.

Perhaps but again, why would they be allowed to do anything to valve timing to rectify a pressure loss in a valve spring system?!!

[autogyro]

Sorry flyn-frog, if Nascar are lossing 300 hp from valve train operation then the engines should be scrapped and proper engines used. I doubt you would be able to turn them over to start them.

If Ferrari reduced the pressure in the (nitrogen) pneumatic valve spring system, the valves would bounce. That is unless they over pressured the original system, which would put way to much load on the cam lobe to valve contact area.
In any case all that would be needed to alter this, would be a variation in the Nitrogen feed line external to the engine.

[donskar]

So technical discusion is not worth the effort.
Says it all.

No. Let me be very clear: YOUR POSTS are not worth the effort.

Are you able to grasp that reality?

[Blackout]

Monaco spec - right

[Hangaku]

So technical discusion is not worth the effort.
Says it all.

No. Let me be very clear: YOUR POSTS are not worth the effort.

Are you able to grasp that reality?

Calm down dear. You should be countering the post, not the poster [-X

[Skinn3r55]

I know compression ratio is not the same as pressure. It's just that someone was posting that the change made to the valves would change the compression ratio and i believe that can't be the case.
Also I didn't mean they would want to change valve lift or duration. Just that having the experience of a few races they might have concluded they could obtain better volumetric efficiency by delaying the intake valve a few degrees.

Perhaps but again, why would they be allowed to do anything to valve timing to rectify a pressure loss in a valve spring system?!!

It was just an ideea. Wanted to see what others would think about it. I guess the FIA would not allow it.

[Skinn3r55]

Wild attempt: the current valves seal the engine better than they used to. Thus, combustion might be more efficient and the compression ratio is increased. This could also allow running a more powerful mix for longer.

Reading what Scarbs wrote it seems that's what they did, and through better valve sealing they gained an estimate 12 HP.

[autogyro]

Wild attempt: the current valves seal the engine better than they used to. Thus, combustion might be more efficient and the compression ratio is increased. This could also allow running a more powerful mix for longer.

Reading what Scarbs wrote it seems that's what they did, and through better valve sealing they gained an estimate 12 HP.

The autogyro quote above is incorrect, I did not say that.

The compression ratio cannot be increased by improving valve sealing.

If the poppet valves were not sealing properly in the first instant, the exhaust valves would burn out rapidly and the engine would not run properly.
I still believe the problem was as first stated, a rapid loss of gas resulting in an inability to recharge the cylinder that supplies gas to the pneumatic valve spring system. To rectify this 'does not' require an improvement to valve sealing. The valves either seal or they do not. If they did not in the last few races, the cars would not have achieved the lap times they did especialy in qualifying. IMO the valves were sealing fine and this is an excuse to justify an increase in power.

[Skinn3r55]

My bad. I was just reffering to the first part.

Wild attempt: the current valves seal the engine better than they used to.

My bad. I was just reffering to the first part