Re: Increasing top speed

Posted by Tim Cole On 2012/3/28 20:51:52

Dear kts68:

Given the interest in ring and pinion change let me put down a few cases:

a) The 7th series Speedster at 3:31 required use of Packard Lo to get going except on the level or better, was 145hp and lighter than the Custom 8 at 106hp

b) Bob Turnquist put 3:56 gears in his 8th series roadster and, at 120hp, it was almost geared too high for the motor. Hans Edwards tried 3:56 gears in his 640 and they were too high (I think it went faster in second gear). Thus, the maximum for the 7th series Custom 8 is probably the 4:06 ratio

c) The 3:56 is fantastic in the twelve given non-mountainous terrain. The fastest I had one up to was 85mph and it was most like a modern car. However, I doubt that top speed was increased by much if any although Packard offered the 4:06 ratio as an option which likely provides the highest top speed on the twelve. With the standard ratio a good running twelve will reach 90mph even in sedan form. In the 9th series Twin Six (160hp) the principle performance attribute is smoothness which makes higher ratios only a consideration as the cars age. Getting out of an eight and into the Twin Six provides an instant impression that is hard to get over. Even though the axle ratios were the same the Twin Six seemed far more relaxed.

How's that?