Stated power output on a 246 is 195bhp at the crank.. anyone figured out how much extra power is produces above 120mph when the air being forced down the carbs really starts having an effect?
Put the car on a rolling road, shoot air in at whatever speed you feel and see what happens...Regards, Alberto
Alberto, thank you for the suggestion, and yes, I suppose I could do that, then again maybe some one else already has. I have driven my dino to the red line on many occasions and for long distances at elevated speeds even more. As speed increases so does mass (right)?, to go faster you need more power. Does the inverse square law apply here...it might as well. The cars slippery shape accounts for some of its speed but it is the uncanny way it keeps acceleration until it finally says enough. It seems to me that the 195 bhp will get you so far but not be enough ( seat of the pants reckoning) to provide grunt all the way to the top. One time I lost the hose that directs air into the filter. i did not replace it right away. I felt no difference poodling around but on a run I felt the car had less to give over 130. It was some time ago and I have though about it from time to time. So i figured it might be worth a conversation
In my opinion it has a effect on the power. The ram air system and the better exhaust system are for me the only differences to the Fiat Dinos which could explain the nominal power difference. The same system was used also on the Alfa GTA from Autodelta and is still in production on high performance super bikes. It gives the engine always cold air from outside which is not heated up and colder air has mored density and therefor more oxigene which creates a stronger combustion. The effect is for sure more working on higher speeds, so here in Germany without speed limit and above 200 km/h there is definitely air over pressure created to the engine. Nicolai
The carbs work like this: the fuel amount is depending directly on the amount of air which goes through the carbs, the air sucks the fuel out of the fuel chamber from the carb. More air in the carbs creates more fuel too. In the right ratio this creates a stronger combustion and therefore more power. On supercharged cars often you can roughly say that 0.1 bar overpressure creates 10 HP. I have no idea what the pressure by the air intake system is but I would say it could created around 5 -8 HP at higher speeds?
To be real honest, in a racing Alfa Romeo, we ended up with consistently better lap times with a foam filter, without an airbox, this, contrary to what was supposed to happen. Yet, the whole engine conpartment was pressurized anyway. Had to change jets to accomodate for this, but in the long run it was a better solution. To top it off, the airbox had zero filter, so the engine was eating up all sorts of trash... In the Dino, I have no clue, as I have never driven one. Will let you know down the road/track. Besides, in the Dino there is no other option but as is. Regards, Alberto
That's what I am trying to figure out. As speed increases so does the speed of the air passing into the air intake. 60kph its going to significant imagine at 180, 200 235. This is not something that can be duplicated (within reason) on a rolling road. That air is being force fed into the carbs.
I tried many moons ago to attach an electric fan to the plenum on a 1750 gtv. my idea of turbocharging hey I was very young and such things were worth spending a whole week end on. Well needless to say it really did not work and I dumped the idea, in favor of more time with my girlfriend The Alfa still has to suck air in, in the Dino it is forced in. I cannot imagine it being an advantage on a road course. In a straight line, however, it (in my opinion) has a measurable effect. I am hoping we have some aeronautical engineers here that will play along. Somewhere there is a formula for calculating the BHP needed to move a vehicle .
In our Dino Club there are some Fiat Dino Spiders which had removed their Carburettorbox against small sport air filters. These smaller filters allow a better view on the beautifull engine and look nice. On the other hand they are just open around and the air which is sucked in is hot and heated from the cylinder heads. On the original cabrurettor box the air comes more or less from the outside and is colder. This change you can feel while driving. The engine sounds louder which may cause a feeling of more power, but it´s not. The engine runs a bit less powerfull and normally even the jets have to be adjusted/changed. This effect is even without any ram air effect, so I estimated this come on top on a Ferrari Dino. I will be soon on a test bench with my 246 to measure the difference between different ignitions. One test only with the coil, one with Dinoplex and the last one with theprogammable megajolt box with two different settings. It is a pitty that I can not test the ram air effect as things like a blower would not represent the driving conditions like on the highway. Best regards Nicolai
Surely the flow rate of the air filter limits the effect of any Ram air effect?. At a certain point, the filter flows it's maximum amount of air through and no matter how hard you try to push more air through, it's not going to happen. At this point, no matter how much faster you go, the same amount of air goes through the carbs.
True, eventually a maximum flow of air is reached, but it is more than just the air filter, its the engines ability to move air which determines its power characteristics. The ram air effect produces more air flow without any other mechanical changes, but withing the costraints of the particular engine. Before the filter limits are reached, benefits are derived. methinks.
