Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Streetwize]
#2241345
01/26/17 12:08 AM
01/26/17 12:08 AM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
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I went quicker adding weight back and no way do I see .2 in that deal.............
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Streetwize]
#2241389
01/26/17 12:58 AM
01/26/17 12:58 AM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Done it, and totally hoped for the physics part of it. 1 pound of Rotational weight is Equal to 3 to 4 pounds of Dead weight. So 60# rotational = about 180# to 240# Think the ratio was more like 1 to 3, its been awhile. Sounds Super, doesn't it. Real world for me, it was Pound for Pound whether it was rotational or Dead weight. So Why was that? I know!! Its because the car has enough time to accelerate in the 1/8-1/4 that the physics effect don't have much effect combined with the acceleration rate. Now, hang that same 60 pounds on the Crankshaft, Different story. So with your change maybe figure .06 as in the Old rule of Thumb. .1 for every 100# and even that is just a, well old rule of thumb and not a exact science.
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Sport440]
#2241417
01/26/17 01:37 AM
01/26/17 01:37 AM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
OP
master
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OP
master
Joined: Jan 2003
Posts: 9,924
Weddington, N.C.
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Here is the article BradH referred to: ( Thanks!) http://www.hotrod.com/articles/light-vs-heavy-wheels-comparison/With the fronts jacked up off the ground you can visualize taking something like an electric motor attached to the hub and accelerating each wheel to simulate top end speed rpm in roughly10.8 seconds taking a lot less energy amps/Kw//Hp than the massively heavy 4x4 wheels that were on it. I guess the et fronts are also about 2" taller so they'll spin a little slower too over the course of a run. 60 pounds is a little more than 2% reduction so roughly like 80 on a 4000 car. My guess is around .15 seconds so probably worth it. Had to drastically cut down the hub register and redrill the bolt pattern to get the fronts to fit. Time will tell tho...i tell you at least its easier to push around the garage, lol
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Streetwize]
#2241449
01/26/17 02:41 AM
01/26/17 02:41 AM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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While I do believe the advantages and would want more weight off the rotational weight vs static weight, even Brads article kind of confirms, that at the rate of witch a car accelerates in the 1/4. that it isn't even Close to the 1# to 3# difference advantage that is and was Advertised of the Physics back in the day or even today. To be accurate, It would have to be Time specific of time traveled with rotational weight differences vs static. Actually more to it then that.
As far as the article, it even shows a lessor gain from the rule of thumb .1 ET for each 100# loss from #3 test, but more, then on test #4
Test 3 shows With a 53.74# weight loss of Rotational, a .034 Gain.
Test 4 shows With a 82.08# weight loss of rotational, a .110 Gain.
Even this testing has accuracy issues. But, All can and Should conclude. No where close to the 1# to 3# advantage of rotational vs static. That I hoped for and most others, not down the 1/4 anyways.
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Streetwize]
#2241537
01/26/17 11:49 AM
01/26/17 11:49 AM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,219
New York
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Read all the blah blah physics about unspung weight and rotating mass Specifically? The tests I've read have no input for the MOI: where is the inertial center of mass of the wheel located? The OD gives nothing useful. Read my article: http://victorylibrary.com/mopar/sprung.htm
Boffin Emeritus
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: jughed]
#2241691
01/26/17 03:30 PM
01/26/17 03:30 PM
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Joined: Jan 2003
Posts: 10,091 MN
JERICOGTX
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,091
MN
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I believe Monte is helping Chad Henderson get the Buick ready for testing. Just saw the car is repainted, and new bullet in.
69 GTX
68 Road Runner
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: JERICOGTX]
#2241816
01/26/17 07:22 PM
01/26/17 07:22 PM
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Joined: Feb 2003
Posts: 1,142 Tucson, AZ
cruzin
super stock
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super stock
Joined: Feb 2003
Posts: 1,142
Tucson, AZ
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Streetwize]
#2250970
02/10/17 12:32 PM
02/10/17 12:32 PM
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Joined: Oct 2007
Posts: 4,219 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,219
New York
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If the wheel weight difference were almost entirely located in the hub, the advantage would be limited to less than 1% change in the overall weight.
Boffin Emeritus
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: Cab_Burge]
#2251456
02/11/17 03:38 AM
02/11/17 03:38 AM
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Joined: Mar 2005
Posts: 557 Stuart FL
mercman1
mopar
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mopar
Joined: Mar 2005
Posts: 557
Stuart FL
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Cab, owned this car for over 20 years and this combo for over 16 years. 6.5 psi on dyno pull after dyno pull. Mallory comp 180 pump with 3/8 lines. Fuel/air is a tad rich at 12.5. It is not lacking fuel. I think this car is maxed out on MY definition of a street car. Pump gas, power steering, power brakes, nice stereo, full auto valve body, 3.73 gears. I know that this combo is not to far away of failing a block. Just a bad tune up or a broken valve spring away. Oh by the way this is a rotisserie restored car that has won 1st place 3 years in a row at Mopars with Big Daddy and in 1999 or 2000 at the Hot Rod magazine Power tour, in a sea of red Camaros, won "Best Street Machine, Non Tubbed" I am always chasing the next tenth, but as stated, the lighter wheel combo and the electric water pump/fan and even removing the power steering belt did nothing to improve ET or MPH on this car.
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Re: Approx ET/MPH change from lighter wheels/tires? Real World?
[Re: mercman1]
#2251462
02/11/17 04:47 AM
02/11/17 04:47 AM
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Joined: Aug 2003
Posts: 43,719 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,719
Bend,OR USA
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Last edited by Cab_Burge; 02/11/17 04:48 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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