HP & Torque numbers for Cross Ram

[olddog]

Mike,

I am recover from Pneumonia, so my head is not right, yet. I only got an hours sleep last night. Enough about me.

I know the 482 is one of the most common strokers. I'm not sure if the extra 16 CI you are shooting for is stroke or bore increase. Frankly it doesn't matter a hole bunch how you get there. CID is CID, as long as you can fit big enough valves to make it breath. After that porting is everything.

The cross ram you describe is interesting. Guys have spent lifetimes perfecting pipe lengths to actually achieve a supercharge affect in a relatively narrow rpm range. The pipe length on both intake and exhaust matter. It can be very real and powerful.

I can talk in generalities. I don't know **** when it comes to the specifics. I do know that increasing the CID on a specific head, intake, exhaust, and cam setup causes the exact same thing to happen at lower rpm. To make it simple, if the only thing you changed on such a system was the CID say from 200 CID to 400 CID, and the 200 CID version made 200 Hp at 4000 rpm the 400 CID version should make 200 Hp at 2000 rpm at double the torque. The two engines should be ingesting the same amount of air, burning the same about of fuel, and making the same Hp.

This example seems upside down when you first here it, but when you think it through, it makes perfect since. A given intake, head and cam combo (exhaust too) pretty much are the main factors that define the air flow dynamic. Thus define the limit of the engine. Ok valve shrouding (bore diameter) would allow a bigger CID engine breath a tad better. Other than that factor, the peak Hp is pretty much set by the maximum air flow. The bore and stroke cause the rpm required to max out the induction system to change and the torque output to change. The bore and stroke do not change the Hp.

That all said, in reality the bore does limit the size of the valves that can be fit into the head. The valves absolutely limit the air flow. But in the case of your FE once you pick the head, this no longer matters.

I have no idea why the fellow objects to more CID. I cannot think of why 16 CID on a nearly 500 CID engine matters all that much to anyone one way or the other.

The only thing I can add is Chrysler experimented with a cross ram dual 4 barrel on a 426 wedge engine in the early 1960's. Each Carb set clean out over the exhaust manifolds on the opposite side of the engine that it fed. From a memory that is failing, I think the air reached supersonic speed in the mid to high 2000 rpm range. I saw several in station wagons. I believe they were trying to get the torque up at highway speeds.

Possibly he objects to more CID because you are move the rpm range down where the ram affect happens. Too many CID may put the peak affect of the cross ram so low in the rpm range that you will end up with stump pulling torque down low and loose all the ram affect so low that it just will not make the Hp.

Enough theory and speculation, assuming you haven't went to sleep.