F7P engine max power potential!!!

[BenR]

jimbo, cheers for the inlet sizes.

inlet=30mm
exhaust=28.5mm
valve seat angles=90degrees both inlet and exhaust.

In theory, the F7P engine, with money not an option and extensive mods to everything, the engine can produce:
max power = 30 x 30 x 3.1416/4 x 8 = 5654.88
max power = 5654.88 x 1.25 = 7068.6/30 = 235.62
max power = 235.62 BHP MAX!

Also, the inlet valves only need 7.5mm of lift to attain their max airflow, so any cam exceeding that amount, will only make it easier.....

And the inlet ports, to achieve respectable flow and airspeed, ahve to be no less than 75% of the diameter of the inlet valves. Or 22.5mm in diameter.

Just thought it would be cool to work it out.
Of course with enough money to make different crank throws and strokes, re-seat the valves at a different angle to increse the size more is possible. On average, inlet valves can be increased by 7%, so max power with larger valves is:
30 x 1.07 = 32.1mm
max power = 32.1 x 32.1 x 3.1416/4 x 8 = 6474.3
maxpower = 6474.3 x 1.25 = 8092.8/30 = 269.76
max power = 269.76 BHP

If this max power is achieved at say 6750rpm then max torque will be:
torque = 269.76 x 5252/6750
torque = 209ft/lbs

5252 is the rpm where all engines torque and horsepower lines will pass on a dynograph. Assuming that they are on the same axis. If you reading shows that the power and torque curvs cross at any other rpm, its wrong!

Not to be relied on, just a rough guide.

 

[Ben H]

Glad to know that youve had an interesting Bank Holiday weekend!!!!

Only joking mate, cheers for that. Is that a flywheel figure?

 

[BenR]

Actually, its at the crank, even before the flywheel, or rather, without it on. And actually, my bank holiday was sh*t ,im stuck inthe middle of nowhere, in retirement capital!!

 

[Nick Read]

Interesting data there Ben, I always wondered what was the most you could wring out of an F7P without forced induction and that kind of makes sense. So how would you rebuild the engine to make 230bhp then? Obvious stuff like porting the head, manifolds, working on the valve seats, wilder cams, lightening and balancing on the bottom end, maybe skimming the head for higher compression?

 

[Ben j]

yeah so what do ya have to do for that then?

 

[Fred@BTM]

spend a couple of quid and youll probably be there by the sounds of it!!!!!

 

[jimbo1]

well the 1993/94 19 16v touring car made 276bhp at 8000rpm. that was using the f7p engine. that was using larger valves(32mm inlet) superwild cams, and roller-barrel throttle bodies-with ram effect!!!

other cars at the time were all 2litre in that class. in the dry it didnt have enough power, but in the wet, it creamed them all!!!

prima racing sell 32mm inlet valves. i think theyre from the clio williams

jimbo

 

[BenR]

Nick, your right, all of the mods you stated are basically all you can do to a N/A engine. Its just how extreeme you go with them, you can get masses to top end power and little bottom or vise versa, it all down to the cylinder head mainly! this is really where all the power is gained, the rest is just mods to reduce the amount of power taken away through friction, heat and noise.
Jimbo, so i want too far off....assuming that i was only using 6750 rpm, not 8000rpm
in all, i say a successful calculation.

 

[bluerxe]

BenR. Just wondering what the equation is for an 8 valve engine (valve diameter = R)?

From looking at your calculations above would it be something like:
((R x R)(Pi/4)(Number of Valves/2)1.25)/30
???

Where does the 1.25 and 30 come from?