100 pound loss = how much HP gain???
Exactly. You change hp/weight ratio which is key in acceleration. Your illustration is the way I looked at it
The problem is all that is for an optimized chassis, clutch/converter (I always put clutch first because real race cars always have 3 pedals), shock tuning, gearing and even hood scoop size and placement (if you have a hood scoop) all factor into it.
That's why when I see any combination sorted out to where the ET matches the MPH I'm impressed. It's damned hard to do. And the quicker you go, the smaller the flaw that will expose itself, and is usually harder to fix.
I did a ton of testing on hood scoops and I can tell most of them are worthless. They are too low and too far forward to do much when you get enough speed to make them function.
And it goes on and on. If you take clutch/ converter out of the equation, the biggest chassis tuning issue is Instant Center and shock tuning. On both ends.
I've watched hours and hours of my customers cars on video and then brought them in to watch it with me. Almost every time, they can't see they are beating the tire to death, or they hit the wheelie bar so hard it unloads the chassis. Or the front is so loose it bangs off the limiters and unloads the entire chassis.
I've watched thousands of runs of cars (especially clutch cars) and really, until you get into Comp Eliminator or really fast bracket cars that data log, most of these cars could benefit from going on the scales and then doing nothing but making 100 foot runs just tuning the shocks.
I forgot about springs. Most guys over spring the hell out of everything, which makes the shocks job all the more difficult. So do ladder bars. Especially with a stick. The Instant Center is too damned high and short for most anything.
So again, the answer is to optimize whatever you have, get it as light as you can within reason and tune it.
I also forgot to mention weight bias. Way too many guys do everything they can to get 50% or more weight on the rear axle. In most cases (and in very high HP cars it's critical) that's the wrong move to make. You end up either moving weight forward, or if you don't have any weight to move, you have to add it to calm the chassis down. And, where you put the weight is critical.