"Sweet Spot" calculations... an***hesis of "SWAG"...! (tech) <HR style="COLOR: #999999" SIZE=1><!-- / icon and ***le --><!-- message --> All of these formulas are available on many websites but this is a simple formula you can write down and use on your cell phone calculator on the road or at the track!!! "Knowing" the math for the correct Gear ratios and tire sizes" that'll compliment your engines "Power Band" known as the "Sweet Spot" and reduce the "SWAG" factor (Scientific Wild *** Guess)! "For instance... let's say you've put an engine together that has 400 hp and 400 ft lbs of torque and the power band is between 2,000 and 5,500 rpm... and you want to determine the gear ratio to achieve the best fuel economy... this is what you'd want to do... Use a formula to select a gear and tire size that would have your engine spinning around 2,100 rpm at 70 mph in top gear. More than likely you've probably have selected a set of tires that compliment your car... so you get rid of another variable by knowing your tire diameter. So the only thing you need to know now is "What Gear Ratio" you'll need to achieve that "Sweet Spot" rpm... To Select Gear Ratio --------- (Tire Dia. x rpm) Divided by (336 x desired mph) = gear ratio example (30" dia. x 2,100 rpm = 63,000)/(336 x 70 mph = 23,520) = 2.68 Basically taking the sums of the 2 equations and dividing 63,000 by 23,520 to come up with the gear ratio of 2.68 Lets say Hypothetically... you want to determine the optimum gear ratio for your car to run 120 mph in the quarter... (Low 11's?) Basically you need to match the top end of your power band to 120 mph... again this is hypothetical not taking in the factors such as car weight... traction..., static drag..., parasitic drag co-efficient..., compression factor... and drivers ability...! Just plug in the 5,500 in the rpm spot and 120 in the mph area... do the calculations and you'll see that you need a 4.09 ge****t...! Since I have a Quick Change differential I've calculated all my Speeds to my engine rpm based on what gear ratio I'm running. Technically I use my tach as a speedometer! To find RPMS for certain speeds The formula I use to determine this is: Ratio x mph x 336 / Tire Diameter = RPM 2.74 x 60 x 336 = 55,238.4 divided by 30" = 1,841 rpm so--------1,840 rpm = 60 mph and ------ 920 rpm = 30 mph It averages around 920 rpm for every 30 mph...! Most of you folks have only one ge****t but you can experiment with different tire sizes to find that "Sweet Spot" but you may not like the way the tires will look on your car...! Racers have been using this formula for years... do you guys use it for the street? It seems that there are a bunch of guys that run whatever they got and hope to run 11's in the quarter and pray to get 30 Miles per gallon? ?? If you don't use this formula... how do you determine how your car will perform on the street and on the strip???"SWAG"????<!-- / message --><!-- sig -->__________________
Good information for those who have a hard time with the math. I've been using those formulas for years to correct for bad speedometers, gear changes, and tire diameter changes. It's good to know the first time you hit the street. Charlie
Thanks wingnutz! I avoided reading this post cuz ofthe ***le, then figured well what the heck is SWAG anyway?!? I'm actually changing my rear right now from a 3.31 to a 2.79 and was wondeirng what the difference would be when I drove it....it'll cruise pretty good at 70mph with the new rear, and more importantly be out of the resonance zone at 1200 rpm at 35mph now!!! Gasmileage I'm sure will ****, so good thing I don't know what it is! Thanks again!
Actually depending on how your engine is set up... you should get slightly better mileage going to the 2.79. But I suspect you'll feel a slight decrease of power on acceleration. Also remember if you're running an overdrive transmission... you'll multiply the RPM number times .70 since overdrives are normally 30 percent.
Oh yeah I know it should theoretically go up but no matter what you do it never amounts to anything like some guys think it will yeah higher gear ratio oughta hurt acceleration, but since I can hardly feather the throttle enough not to burn out as it is I'm cool with that. I *hope* I have the problem that I need a shorter gear for acceleration! That'd mean I had traction for a change!!!! But really I'm swapping rears I shoulda said, so this was the rear that fit that I could buy for $60, so I'll take whatever ratio it has!
Say I have an over drive transmision, I think mine is 68% or 0.68 , would I just multiply that and the engin RPM's togeter first?
Hahaha.. sounds about right...! But if you did want to swap out gears you'll have a better idea what'll work better for you performance wise. This depends on what you're trying to accomplish. To find your operating RPM using the (ratio x mph x 336) divided by tire dia. I'd just use the .68 x rpm to see where'd you be on the tach for each speed with overdrive engaged. But for figuring out What gear to run while overdrive is engaged I'd change the equation a bit... For example I'm changing out my turbo 400 for a 700R4 overdrive transmission and I want to have the final drive (overdrive) about the same rpm range as the turbo 400 at 70 mph which would be around 2,100 rpm with my 2.74 ge****t... I allready know the key elements such as 70 mph 2,100 rpm, 2.74 gears and my tires are 30" diameter... So to make it Simple I've taken the ge****t number times 1.32 (.68 when in overdrive) and calculated 2.74 x 1.32 = 3.62 ge****t Then do the calculation again and multiply the RPM number times .68 and it'll give you your rpm when cruising down the freeway at 70ph in overdrive. I'm sure there are better wys to describe what I'm trying to accomplish... but it is fun knowing the basic formulas and play around with the numbers to get the desired results!
Nope, that's wrong. The correct thing to do is put 4.10's in everything and do really hard launches and burn up valve springs on the highway. That's great info, thanks man. Going in the secret drawer in my desk at work.
Good formulas, I use these a fair amount............glad you reposted them today, I needed to run a setup for the ModelA
Math, smath. I just go here when I need to calculate that stuff. Used it a lot when picking the gear ratio and tires size for the '55. And when I changed gear ratios in the coupe.
My girlfriend asked the same thing and then I showed her the camera on her phone as well...! Your's prolly got a camera on it to...!!! __________________ If you were "REALLY" old school... I'd suggest a "SLIDE RULE" or a Pencil...! But you can pry one of those calcultor thingys off of some shopping carts... they'll work! Here are some "Fun Numbers" 1/8th mile conversions to 1/4 mile e.t.s from Texas Muscle car club 1/8 Mile To 1/4 Mile ET Conversion Chart <TABLE cellSpacing=1 width=578 border=1><TBODY><TR><TD vAlign=center align=middle width=62>1/8-mile ET</TD><TD vAlign=center align=middle width=59>1/4-mile ET</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>1/8-mile ET</TD><TD vAlign=center align=middle width=61>1/4-mile ET</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>1/8-mile ET</TD><TD vAlign=center align=middle width=62>1/4-mile ET</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>1/8-mile ET</TD><TD vAlign=center align=middle width=61>1/4-mile ET</TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5</TD><TD vAlign=center align=middle width=59>7.80</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>6.8 </TD><TD vAlign=center align=middle width=61>10.61 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.55 </TD><TD vAlign=center align=middle width=62>13.34 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.3 </TD><TD vAlign=center align=middle width=61>16.07 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.05</TD><TD vAlign=center align=middle width=59>7.88</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>6.85 </TD><TD vAlign=center align=middle width=61>10.69 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.6 </TD><TD vAlign=center align=middle width=62>13.42 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.35 </TD><TD vAlign=center align=middle width=61>16.15 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.1</TD><TD vAlign=center align=middle width=59>7.96</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>6.9 </TD><TD vAlign=center align=middle width=61>10.76 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.65 </TD><TD vAlign=center align=middle width=62>13.49 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.4 </TD><TD vAlign=center align=middle width=61>16.22 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.15</TD><TD vAlign=center align=middle width=59>8.03</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>6.95 </TD><TD vAlign=center align=middle width=61>10.84 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.7 </TD><TD vAlign=center align=middle width=62>13.57 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.45 </TD><TD vAlign=center align=middle width=61>16.30 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.2</TD><TD vAlign=center align=middle width=59>8.11</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7 </TD><TD vAlign=center align=middle width=61>10.92 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.75 </TD><TD vAlign=center align=middle width=62>13.65 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.5 </TD><TD vAlign=center align=middle width=61>16.38 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.25</TD><TD vAlign=center align=middle width=59>8.19</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.05 </TD><TD vAlign=center align=middle width=61>11.00 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.8 </TD><TD vAlign=center align=middle width=62>13.73 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.55 </TD><TD vAlign=center align=middle width=61>16.46 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.3</TD><TD vAlign=center align=middle width=59>8.27</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.1 </TD><TD vAlign=center align=middle width=61>11.08 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.85 </TD><TD vAlign=center align=middle width=62>13.81 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.6 </TD><TD vAlign=center align=middle width=61>16.54 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.35</TD><TD vAlign=center align=middle width=59>8.35</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.15 </TD><TD vAlign=center align=middle width=61>11.15 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.9 </TD><TD vAlign=center align=middle width=62>13.88 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.65 </TD><TD vAlign=center align=middle width=61>16.61 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.4</TD><TD vAlign=center align=middle width=59>8.42</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.2 </TD><TD vAlign=center align=middle width=61>11.23 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>8.95 </TD><TD vAlign=center align=middle width=62>13.96 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.7 </TD><TD vAlign=center align=middle width=61>16.69 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.45</TD><TD vAlign=center align=middle width=59>8.50</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.25 </TD><TD vAlign=center align=middle width=61>11.31 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9 </TD><TD vAlign=center align=middle width=62>14.04 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.75 </TD><TD vAlign=center align=middle width=61>16.77 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.5</TD><TD vAlign=center align=middle width=59>8.58</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.3 </TD><TD vAlign=center align=middle width=61>11.39 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.05 </TD><TD vAlign=center align=middle width=62>14.12 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.8 </TD><TD vAlign=center align=middle width=61>16.85 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.55</TD><TD vAlign=center align=middle width=59>8.66</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.35 </TD><TD vAlign=center align=middle width=61>11.47 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.1 </TD><TD vAlign=center align=middle width=62>14.20 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.85 </TD><TD vAlign=center align=middle width=61>16.93 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.6</TD><TD vAlign=center align=middle width=59>8.74</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.4 </TD><TD vAlign=center align=middle width=61>11.54 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.15 </TD><TD vAlign=center align=middle width=62>14.27 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.9 </TD><TD vAlign=center align=middle width=61>17.00 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.65</TD><TD vAlign=center align=middle width=59>8.81</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.45 </TD><TD vAlign=center align=middle width=61>11.62 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.2 </TD><TD vAlign=center align=middle width=62>14.35 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>10.95 </TD><TD vAlign=center align=middle width=61>17.08 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.7</TD><TD vAlign=center align=middle width=59>8.89</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.5 </TD><TD vAlign=center align=middle width=61>11.70 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.25 </TD><TD vAlign=center align=middle width=62>14.43 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11 </TD><TD vAlign=center align=middle width=61>17.16 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.75</TD><TD vAlign=center align=middle width=59>8.97</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.55 </TD><TD vAlign=center align=middle width=61>11.78 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.3 </TD><TD vAlign=center align=middle width=62>14.51 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.05 </TD><TD vAlign=center align=middle width=61>17.24 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.8</TD><TD vAlign=center align=middle width=59>9.05</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.6 </TD><TD vAlign=center align=middle width=61>11.86 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.35 </TD><TD vAlign=center align=middle width=62>14.59 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.1 </TD><TD vAlign=center align=middle width=61>17.32 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.85</TD><TD vAlign=center align=middle width=59>9.13</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.65 </TD><TD vAlign=center align=middle width=61>11.93 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.4 </TD><TD vAlign=center align=middle width=62>14.66 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.15 </TD><TD vAlign=center align=middle width=61>17.39 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.9</TD><TD vAlign=center align=middle width=59>9.20</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.7 </TD><TD vAlign=center align=middle width=61>12.01 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.45 </TD><TD vAlign=center align=middle width=62>14.74 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.2 </TD><TD vAlign=center align=middle width=61>17.47 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>5.95</TD><TD vAlign=center align=middle width=59>9.28</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.75 </TD><TD vAlign=center align=middle width=61>12.09 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.5 </TD><TD vAlign=center align=middle width=62>14.82 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.25 </TD><TD vAlign=center align=middle width=61>17.55 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6</TD><TD vAlign=center align=middle width=59>9.36</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.8 </TD><TD vAlign=center align=middle width=61>12.17 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.55 </TD><TD vAlign=center align=middle width=62>14.90 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.3 </TD><TD vAlign=center align=middle width=61>17.63 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.05</TD><TD vAlign=center align=middle width=59>9.44</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.85 </TD><TD vAlign=center align=middle width=61>12.25 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.6 </TD><TD vAlign=center align=middle width=62>14.98 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.35 </TD><TD vAlign=center align=middle width=61>17.71 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.1</TD><TD vAlign=center align=middle width=59>9.52</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.9 </TD><TD vAlign=center align=middle width=61>12.32 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.65 </TD><TD vAlign=center align=middle width=62>15.05 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.4 </TD><TD vAlign=center align=middle width=61>17.78 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.15</TD><TD vAlign=center align=middle width=59>9.59</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>7.95 </TD><TD vAlign=center align=middle width=61>12.40 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.7 </TD><TD vAlign=center align=middle width=62>15.13 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.45 </TD><TD vAlign=center align=middle width=61>17.86 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.2</TD><TD vAlign=center align=middle width=59>9.67</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8 </TD><TD vAlign=center align=middle width=61>12.48 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.75 </TD><TD vAlign=center align=middle width=62>15.21 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.5 </TD><TD vAlign=center align=middle width=61>17.94 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.25</TD><TD vAlign=center align=middle width=59>9.75</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.05 </TD><TD vAlign=center align=middle width=61>12.56 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.8 </TD><TD vAlign=center align=middle width=62>15.29 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.55 </TD><TD vAlign=center align=middle width=61>18.02 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.3</TD><TD vAlign=center align=middle width=59>9.83</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.1 </TD><TD vAlign=center align=middle width=61>12.64 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.85 </TD><TD vAlign=center align=middle width=62>15.37 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.6 </TD><TD vAlign=center align=middle width=61>18.10 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.35</TD><TD vAlign=center align=middle width=59>9.91</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.15 </TD><TD vAlign=center align=middle width=61>12.71 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.9 </TD><TD vAlign=center align=middle width=62>15.44 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.65 </TD><TD vAlign=center align=middle width=61>18.17 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.4</TD><TD vAlign=center align=middle width=59>9.98</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.2 </TD><TD vAlign=center align=middle width=61>12.79 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>9.95 </TD><TD vAlign=center align=middle width=62>15.52 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.7 </TD><TD vAlign=center align=middle width=61>18.25 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.45</TD><TD vAlign=center align=middle width=59>10.06</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.25 </TD><TD vAlign=center align=middle width=61>12.87 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10 </TD><TD vAlign=center align=middle width=62>15.60 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.75 </TD><TD vAlign=center align=middle width=61>18.33 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.5</TD><TD vAlign=center align=middle width=59>10.14</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.3 </TD><TD vAlign=center align=middle width=61>12.95 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10.05 </TD><TD vAlign=center align=middle width=62>15.68 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.8 </TD><TD vAlign=center align=middle width=61>18.41 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.55</TD><TD vAlign=center align=middle width=59>10.22</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.35 </TD><TD vAlign=center align=middle width=61>13.03 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10.1 </TD><TD vAlign=center align=middle width=62>15.76 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.85 </TD><TD vAlign=center align=middle width=61>18.49 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.6</TD><TD vAlign=center align=middle width=59>10.30</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.4 </TD><TD vAlign=center align=middle width=61>13.10 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10.15 </TD><TD vAlign=center align=middle width=62>15.83 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.9 </TD><TD vAlign=center align=middle width=61>18.56 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.65</TD><TD vAlign=center align=middle width=59>10.37</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.45 </TD><TD vAlign=center align=middle width=61>13.18 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10.2 </TD><TD vAlign=center align=middle width=62>15.91 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>11.95 </TD><TD vAlign=center align=middle width=61>18.64 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.7</TD><TD vAlign=center align=middle width=59>10.45</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60>8.5 </TD><TD vAlign=center align=middle width=61>13.26 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61>10.25 </TD><TD vAlign=center align=middle width=62>15.99 </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59>12 </TD><TD vAlign=center align=middle width=61>18.72 </TD></TR><TR><TR bgColor=#ffffff><TD vAlign=center align=middle width=62>6.75</TD><TD vAlign=center align=middle width=59>10.53</TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=60> </TD><TD vAlign=center align=middle width=61> </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=61> </TD><TD vAlign=center align=middle width=62> </TD><TD vAlign=center borderColor=#000000 align=middle width=3 bgColor=#000000> </TD><TD vAlign=center align=middle width=59> </TD><TD vAlign=center align=middle width=61> </TD></TR></TBODY></TABLE>
Do you think a 20% increase is good? After getting the next higher gear in the rear end, rebuilding the carb., RV cam, straight up timing and new heads on my old (but not old enough to not be OT) motorhome 460 Ford, I increased my gas mileage 20%...It went from 5 MPG to 6 MPG...There's how math can fool you.
It can be "Smoke and Mirrors ' however in the game of Quarter mile e.t.s the race is won or lost sometimes by Thousandths of a second...! I've studied many engine builder/racers like "Grumpy" Bill Jenkins, "Smokey Yunik", Reeves Calloway and Gail Banks and discovered cheap horse power by obtaining the right combination mathumatically rather than throwing "Cubic Dollars" into the drivetrain and ending up with the wrong combination. It's hard to justify a 20% in your case but any Racer would be more than happy to obtain that number...!
Wingnutz, thanks for this treatise on where math is our friend! I am ruminating on how to reconcile the seeming difference between intellectual and intuitive approaches to solutions. If something feels right, in terms of a drag strip performance measure. Then I suspect it is in part, because you have a familiarity. This means you have taken in both data (facts, measurements) and the seat-of-the-pants or "felt" experience of power to-the-pavement and results. It is an interesting arena... Not wishing to hi-jack here.
Don't get me wrong. I think a 20% increase is huge, I was only trying to illustrate how deceiving it can be...If I say I increased my mileage from 5 MPG to 6 MPG it's a yawner. But when I say I increased it 20% it paints a different picture. BTW, increasing my gas mileage wasn't my goal, performance was and I got both.
The Jalopy Journal
