Corner weights
#1848240
06/13/15 07:14 PM
06/13/15 07:14 PM
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Joined: Feb 2006
Posts: 698 Alberta Canada
Edge
OP
mopar
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OP
mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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After more than a year since starting a new job I dug my car out and started working on it again.
Car is biased pretty heavy on the left side
LF 642 RF 587 LR 567 RR 512
This race ready including driver less fuel and transmission oil.
I have set ride hts the same on both fronts ( 3.5 )and both rears ( 4.5).
Should I be concerned about being 50 lbs light on the right rear ?
Last edited by Edge; 06/13/15 07:36 PM.
76 Duster
work in progress
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Re: Corner weights
[Re: Edge]
#1848524
06/14/15 03:31 AM
06/14/15 03:31 AM
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Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
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After more than a year since starting a new job I dug my car out and started working on it again.
Car is biased pretty heavy on the left side
LF 642 RF 587 LR 567 RR 512
This race ready including driver less fuel and transmission oil.
I have set ride hts the same on both fronts ( 3.5 )and both rears ( 4.5).
Should I be concerned about being 50 lbs light on the right rear ?
I've seen those ratio many times on many BB Mopars, A,B and E bodys Is the battery mounted on the right side as far back as you can get it? If not try that as the first step. The car should be bettr with more weight on the right rear than the left rear so see what you can do including adding ballast back there Let us know your results please
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Corner weights
[Re: Cab_Burge]
#1848544
06/14/15 07:53 AM
06/14/15 07:53 AM
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Joined: Jan 2003
Posts: 10,016 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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The car is 200 lbs heavy on the driver's side, and 75 lbs heavy on the front on both sides if you look at it that way. The front to rear is about the same percent on either side. You could start there, and add a touch of weight if it goes right on launch. Maybe even start by moving 10 from drive to pass side. What was it before?
Last edited by gregsdart; 06/14/15 07:54 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Corner weights
[Re: dvw]
#1848849
06/14/15 04:24 PM
06/14/15 04:24 PM
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Joined: Feb 2006
Posts: 698 Alberta Canada
Edge
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mopar
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OP
mopar
Joined: Feb 2006
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Alberta Canada
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Tried to put as much on the rights side of the car as practical but hard to compensate for my weight in the drivers seat. I will have to see what else I can move over. Won't be able to be complete and test until next spring as time and money permits but happy to find time to start to work on the car. Thanks for the advice.
76 Duster
work in progress
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Re: Corner weights
[Re: Edge]
#1848896
06/14/15 06:28 PM
06/14/15 06:28 PM
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Joined: Jan 2003
Posts: 19,382 Las Vegas
Al_Alguire
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I Live Here
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Las Vegas
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What suspension front and rear??
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Corner weights
[Re: Al_Alguire]
#1848912
06/14/15 06:47 PM
06/14/15 06:47 PM
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Joined: Feb 2006
Posts: 698 Alberta Canada
Edge
OP
mopar
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OP
mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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Its a full chassis car so strut front and four link rear.
76 Duster
work in progress
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Re: Corner weights
[Re: Edge]
#1848959
06/14/15 07:49 PM
06/14/15 07:49 PM
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Joined: Jan 2003
Posts: 19,382 Las Vegas
Al_Alguire
I Live Here
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I Live Here
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Posts: 19,382
Las Vegas
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Then you need to take a hard look at whats going on there. Certainly don't want the rear weights where they are at now IMO. Assume all this was witht he 4 link set to neutral(no preload) and all the spring heights at each corner equal, ie springs all have the same amount of preload. One other important thing people overlook is make sure you have the tire pressure where it will be raced. A pound of air can move corners weights around pretty significantly.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Corner weights
[Re: Al_Alguire]
#1849200
06/14/15 11:48 PM
06/14/15 11:48 PM
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Joined: Feb 2006
Posts: 698 Alberta Canada
Edge
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mopar
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OP
mopar
Joined: Feb 2006
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Alberta Canada
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I did not check tire pressures thats a good suggestion thanks.
How fast, dont know yet but I have a couple of motors and the first one is B1 deal so it will start out as a 8 second car and down the road I have a boosted motor to install.
I also heard back from a friend with a TS car that has run 6.86 and he told me that with his car he is not concerned with corner weights and the set up is focussed on ride hts and the front rear bias. His explanation to me was that corner weights go completely out the window at launch.
Then he started talking about the rear steer in his set up and lost me... I have quite a bit to learn.
76 Duster
work in progress
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Re: Corner weights
[Re: Edge]
#1849457
06/15/15 11:25 AM
06/15/15 11:25 AM
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Joined: Jan 2003
Posts: 10,016 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,016
Frostbitefalls MN (Rocky&Bullw...
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I just caught the part about you figuring it will be an 8 sec ride, with more to come. IMHO,get as much weight to the pass side as you can to get closer to even, then get it scaled by a chassis builder that races or crews for a car fast as or faster than what you are planning on. I went to a local guy that built chassis and was running a shoebox Chev, deep into the 8s, best money I have spent. The first trip to the track and I had to change one side of the wheelie bars by a 1/4 inch, and it launched dead perfect.
Last edited by gregsdart; 06/15/15 11:31 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Corner weights
[Re: Edge]
#1849489
06/15/15 12:00 PM
06/15/15 12:00 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I did not check tire pressures thats a good suggestion thanks.
How fast, dont know yet but I have a couple of motors and the first one is B1 deal so it will start out as a 8 second car and down the road I have a boosted motor to install.
I also heard back from a friend with a TS car that has run 6.86 and he told me that with his car he is not concerned with corner weights and the set up is focussed on ride hts and the front rear bias. His explanation to me was that corner weights go completely out the window at launch.
Then he started talking about the rear steer in his set up and lost me... I have quite a bit to learn. One thing with chassis weight.. you end up adding pre-load to make the car launch straight... so if you add a lot to over come the weight being in the wrong places... but when you add pre-load it will do the opposite thing on shut down.. when you snap out of the pedal it will tend to go left... and if you have a lot of load it really wants to go left... get the corners close with everything at zero(pre-loads and anti roll) then once you get your corner weights close then add the pre load and keep the anti roll at zero... pre-load is based more on the torque you have... a ton of torque will try to drive the car to the right so you have to add more pre-load to counter the torque REMEMBER TO HAVE THE CAR AT RACE WEIGHT AND THE DRIVERS WEIGHT IN THE CAR when you start playing with corner weights and pre-load EDIT On my 4 link and anti roll bar I will disconnect the upper right bar(I pull the bolt on the front of that bar)till I get the weights to where I want... otherwise you keep chasing the bar loading up as you move weight... then the last thing is to hook up the anti roll bar... I use zero lad there
Last edited by MR_P_BODY; 06/15/15 12:06 PM.
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Re: Corner weights
[Re: Edge]
#1849520
06/15/15 12:30 PM
06/15/15 12:30 PM
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Joined: Jan 2012
Posts: 2,678 Stuttgart, Arkansas
rickseeman
master
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master
Joined: Jan 2012
Posts: 2,678
Stuttgart, Arkansas
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After more than a year since starting a new job I dug my car out and started working on it again.
Car is biased pretty heavy on the left side
LF 642 RF 587 LR 567 RR 512
This race ready including driver less fuel and transmission oil.
I have set ride hts the same on both fronts ( 3.5 )and both rears ( 4.5).
Should I be concerned about being 50 lbs light on the right rear ?
My car weighs within 10 lbs of yours. Mine is almost 150 lbs heavier on the left front than the right rear like yours. I think this is all normal. The motor is in the front and the driver sits on the left so the weight is where it is like most every other race car. My car launches fine and I think yours will too. I believe you are over thinking this. https://vimeo.com/44009973P.S. If you are going to have a chassis car read Jerry Bickel's book and Rick Jones' book.
Last edited by rickseeman; 06/15/15 01:04 PM.
2011 Drag Pak Challenger
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Re: Corner weights
[Re: Edge]
#1849721
06/15/15 04:37 PM
06/15/15 04:37 PM
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Joined: Dec 2005
Posts: 11,692 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,692
Fulton County, PA
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If I were involved in this, I would want to see the RR a bit heavier with the driver in the car. Maybe equal to or just a few pounds lighter than the LR. Without the drivers weight in the car, I would expect the RR to be at least 20 or 30 pounds heavier than the LR. This will certainly cause the LF to be heavier than the RF. Moving the weight can be accomplished a number of different ways. 4 link preload, spring height, moving ballast, a combination of any of those, etc. Unsprung wheelie bars are also a tuning tool.
Many things influence this. Torque and power levels, trans type and gear ratio, 4 link geometry, spring rates, etc. Consider the initial set-up to be a baseline intended to get the car down the track. Adjustments, based on what the car does, can be made from that point, but you need to know where it is initially. If the weights are close, the car should go reasonably straight. If it tries to run over the tree, something else is wrong.
If the results don't match the theory, change the theory.
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Re: Corner weights
[Re: rickseeman]
#1849735
06/15/15 05:08 PM
06/15/15 05:08 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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After more than a year since starting a new job I dug my car out and started working on it again.
Car is biased pretty heavy on the left side
LF 642 RF 587 LR 567 RR 512
This race ready including driver less fuel and transmission oil.
I have set ride hts the same on both fronts ( 3.5 )and both rears ( 4.5).
Should I be concerned about being 50 lbs light on the right rear ?
My car weighs within 10 lbs of yours. Mine is almost 150 lbs heavier on the left front than the right rear like yours. I think this is all normal. The motor is in the front and the driver sits on the left so the weight is where it is like most every other race car. My car launches fine and I think yours will too. I believe you are over thinking this. https://vimeo.com/44009973P.S. If you are going to have a chassis car read Jerry Bickel's book and Rick Jones' book. Both of those books are well worth having.. I have them and a couple others... when I built my car(and a few others) the corner weights came out very close.. even with me in the seat (within 70# but I weigh parts before they get put in... and I will move the engine/trans to help this issue.. my car front/ back bias is 48/52 with me in the seat... its 50/50 with out me EDIT The pre-load on the 4 link is 18#... this thing drives arrow straight all the way down track... as in hands free... I had the steering wheel pop off one time and I got it back on at about 300' out and still got that round win
Last edited by MR_P_BODY; 06/15/15 05:12 PM.
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Re: Corner weights
[Re: Edge]
#1849911
06/15/15 09:01 PM
06/15/15 09:01 PM
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Joined: Jun 2011
Posts: 39 Yanceyville, NC
JGriffit
member
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member
Joined: Jun 2011
Posts: 39
Yanceyville, NC
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I don't post here much, but here are the numbers on my Avenger Things I have learned about setting up four links: Ride heights exact Tire pressures exact All front end alignment settings set Race weight , driver, fluids Pinion angle set Top right link disconnected or zero preload Disconnect anti roll bar Scale it ( Be real sure the scales are level side to side front to back. This is critical)
I follow the Rick Jones and JBRC recommendation of having 40-60 lbs heavy on LR and set the car up that way
I then set zero preload on the four link and ARB. Occasionally I have to add a flat depending on track conditions. Drives straight as a string.
99 Dodge Avenger Best Machine 428 ET 8.90 150MPH BLP Carbs Ultimate Converter Concepts
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Re: Corner weights
[Re: JGriffit]
#1851713
06/18/15 12:06 PM
06/18/15 12:06 PM
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Joined: Feb 2006
Posts: 698 Alberta Canada
Edge
OP
mopar
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OP
mopar
Joined: Feb 2006
Posts: 698
Alberta Canada
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Very helpful and informative, thanks for all of the advice. I think I will pick up a chassis book or two and more importantly complete this car.
76 Duster
work in progress
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