What would be your estimates that the following changes would make a T engine produce over and above its original 20HP.
Scat (Original spec) crank, .020 OS aluminium pistons, Chaffins 280 cam, Waukesha Ricardo head, high volume intake manifold, rebuilt Stromberg OF carb.
Unsure if I'll use a Model A exhaust manifold or custom build a set of headers. Coil plate removed ad all magnets replaced with slingers. Balanced flywheel.
I keep getting asked the question from other members of my generic car club and although I have a rough idea, I must admit that I am curious myself.
Sorry, I don't remember which magazine it was, but within the last couple of years the VF or the MTT had dynamometer test results and told what modifications, if any, were on the cars. As I recall, some were under 10 HP and a couple were over 40 HP. Maybe one of those cars had equipment similar to yours and would give you some idea.
The dynamometer tests in the magazine were made on the rear wheels of the cars on a tour, as I remember. Thus the Hp values shouldn't be directly compared with Ford's claimed 20 hp at the crank shaft (or was it at the transmission output shaft?)
Ford's value could perhaps be reduced by 30% (?) to account for the losses in the u-joint, rear axle, exhaust system etc, when compared with dyno values from the rear wheels.
But if a loose engine is tested in a bench, I've seen values like 26 hp from a modern alu piston rebuild with a Z head, while the same engine topped out at 28 hp with a Prus head. With a Waukesha head you get a cool look but lower compression, more like a standard low head, while the stromberg may help a lot - maybe the net result is like with a Z head, but that's only speculation from me. The torque at 800-1000 rpm when climbing a hill is more important than the top end power at 1600 rpm for most T drivers.
I have run a Ricard head and Stromberg OF on my speedster. Although I have not done any dyno pulls, the engine felt much less powerful than with the Sherman Super Fire/Winfield model S updraft carb set up. Both engine setups used a Model B grind cam, Winfield manifold, open exhaust, distributor and no magnets on the flywheel.
As Roger pointed out, the Ricardo head does not really raise compression but does increases combustion efficiency.
The Sherman Super Fire/Winfield set up produced great hill climbing power. I could accelerate up some pretty steep hills with throttle to spare. With the Ricardo/Stromberg setup, I have to run to wide open and chug up the same hills.
Thanks Steve, Roger and Tom.
I've found the following from looking around various websites.
Tulsa club dyno tests say the Waukesha Ricardo head gave approximately 3 hp. Chaffins claim the high vol intake adds 2 hp. I read somewhere that the 280 cam should give 3hp.
So that leaves the lighter weight and slightly oversize pistons, that should add some, along with a counter-weighted crankshaft, 7kgs lighter flywheel and the better breathing OF carb should add some too. Any guesses or learned estimates there?
The lighter flywheel may increase the rate of speed increase but there would be no increase in horsepower or torque.