Re: What about the 25K 105mph V8 Patrician?

Posted by Rusty O\'Toole On 2011/4/9 10:29:35

"So i'm not sure how u arrived at 3.54 as a "stock" rear axle ratio."

I was quoting Chuck's post.

In any case, I would bet Packard used the 3.54 gears or even lower (higher numerical). To those not used to high speed competition this may seem scary. But in practice, for a run like that, you want the engine running at the speed that gives max HP or close to it. As long as the engine is capable of maintaining 4600 RPM without overheating or blowing up, this is easier on the engine than straining at a lower RPM. Plus, I severely doubt they could have made that speed with a higher gear. Remember they did the run on a banked oval track, this means more friction or resistance than a flat straight track. Plus they had to push a full size Patrician body through dense, cold, wet air in the rain.

One experience that comes to mind is this. About the same time as this run took place, within a year or 2, Chrysler took some cars to Daytona Beach expecting to break all speed records. They didn't make it. Tom McCahill warned them that they needed a lower rear axle ratio to make the speed they needed. Ideally, the engine should be revving OVER its max HP speed when they went through the traps. Chrysler's engineers replied that their blockbuster Hemi engine could pull the higher ratio through 4 feet of fresh snow. They were wrong. The dense sea level air and the drag of the wet sand defeated them.

A week later they took McCahill's advice and tried again this time with the stemwinder gears he recommended. They finished the run with engines screaming and added 5 or 10 MPH to their speed, ample to have set new records. But it was too late, Speed Week was over.

The same car or cars, could have been geared higher and would have gone faster at Bonneville because of the thin dry air at high altitude. The thin air would have reduced HP by 10% or so but by the same token, would have cut air resistance.

The 3.54 ratio would give a speed of 120 @ 4600RPM which is where their engine made max horsepower. This ratio, or close to it, would have been the best choice for a sustained high speed run. With a lower numerical ratio I doubt they could have even reached the required speeds let alone maintain them for 25000 miles.