SBC Flat Plane
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Generally this is true, but for the NASCAR example, extra weight does impact top speed due to the greater tire deflection in the heavier car (where in NASCAR everyone is using the same tire specs). The extra power that is required to offset the tire deflection cannot be used for top speed. In a sport like NASCAR where the differences between winning and losing are often razor thin, extra weight will negatively impact a competitor in top speed.
For flat plane cranks, please see the attached picture from "The Design and Tuning of Competition Engines" by Philip H. Smith (6th Edition). This might help some of the discussion.
For flat plane cranks, please see the attached picture from "The Design and Tuning of Competition Engines" by Philip H. Smith (6th Edition). This might help some of the discussion.
In October 2007 American race car driver Russ Wicks set a speed record for stock cars in a 2007-season Dodge Charger built to NASCAR specifications by achieving a maximum speed of 244.9 mph (394.1 km/h) at Bonneville Speedway.[9][10]
But how about some context? Note that I didn't bring "NASCAR" into this discussion. Note that if you added weight, you could also increase tire pressure to retain the same tire deflection. Note that this is getting into the "minutia" of not relevant....I used "car top speeds" and their weights as an example to show how lightening a crank shaft doesn't naturally make it spin a faster speed. It makes it accelerate more quickly, but it doesn't change it's "top speed" in a meaningful way.
WRT the posted text, I am pretty sure that I'd already covered the benefits of Flat cranks in post #3.
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Last edited by Tom400CFI; May 4, 2021 at 05:45 PM.
Burning Brakes
Joined: Nov 2000
Posts: 986
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