Brought to you in part by:

Great deals on auto restoration supplies!

.


  Mustangsandmore Forums
  Ford Racing
  weight transfer?

Post New Topic  Post A Reply
profile | register | preferences | faq | search

next newest topic | next oldest topic
Author Topic:   weight transfer?
capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-10-2002 10:13 PM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
a guy watching my burnout today commented that only my right slick was smoking. the rear is locked, both tires were turning. then i noticed that after a run the right slick was hotter than the left. what do you guys think?

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

n2oMike
Gearhead

Posts: 2831
From: Spencer, WV
Registered: Jan 2001

posted 03-10-2002 10:21 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
One tire was probably submerged in water during the burnout... and not the other.

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

[This message has been edited by n2oMike (edited 03-10-2002).]

IP: Logged

capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-10-2002 10:24 PM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
mike, i checked the rear end and it is fine. it was not just on one run, the right is warmer on every run. just wondering if the left side is picking up for some reason. thanks

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

Dave_C
Gearhead

Posts: 1069
From: Gadsden, Al
Registered: Aug 99

posted 03-11-2002 12:00 AM     Click Here to See the Profile for Dave_C   Click Here to Email Dave_C     Edit/Delete Message   Reply w/Quote
It's like that as most likley it has more weight on it.

Notice how many drag cars will only pull the left front wheel or if it pulls both the left front goes higher. When it does that it puts more weight on the wheel that is diagonal from it, the right rear. It's from the torque reaction on the rear axle. If you have an adjustable setup like ladder bars, 4 link, etc, you can adjust it out of it.

If it's not causing a handling problem I wouldn't worry about it. Just rotate the slicks every 25 passes or so to even out the wear.

Later,

David Cole

IP: Logged

TomP
Gearhead

Posts: 6120
From: Delta BC Canada
Registered: Dec 99

posted 03-11-2002 01:35 AM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
actually there is more weight on the left rear...its why cars often need to be steered after launching. The torque pushes DOWN on the left rear tire and tries to lift the right rear UP.... lifting the right rear tire up is compressing the spring which drops that corner of the car down.

The left side of the car lifting is caused by the axle housing driving downwards,
thats why the left rises and the right side squats. The left tire has more grip and tries to push the car forward harder, the suspension geometery usually means the extended left side is further forward driving the car to the right. Its also why the left axle breaks first.

Take all the shocks out and this will become readily apparent

[This message has been edited by TomP (edited 03-11-2002).]

IP: Logged

Richard Swart
Gearhead

Posts: 154
From: Graham, Wa.
Registered: Oct 99

posted 03-11-2002 07:36 AM     Click Here to See the Profile for Richard Swart   Click Here to Email Richard Swart     Edit/Delete Message   Reply w/Quote
could a rear sway bar help this problem?

------------------
64 Fairlane 351w thunder-nut. 68 Torino formal roof 351w. 68 cougar GTE. 70 cougar 351w aod trany.73 F-100 4x4 428 tri-power.

IP: Logged

capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-11-2002 09:23 AM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by TomP:

Take all the shocks out and this will become readily apparent

[This message has been edited by TomP (edited 03-11-2002).]


thanks but no thanks tom!! hee hee
in my silly little brain, it seems like there would be more weight on the right pushing it down on the track harder, thus more smoke and more heat. thanks

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

Dave_C
Gearhead

Posts: 1069
From: Gadsden, Al
Registered: Aug 99

posted 03-11-2002 09:24 AM     Click Here to See the Profile for Dave_C   Click Here to Email Dave_C     Edit/Delete Message   Reply w/Quote
Tom P,

That didn't come out the exact way I meant it too. A correctly setup car will show more weight on the right rear. According to Dave Morgan (Doorslammer's The Chassis Book) you want the right rear to weigh more to offset the torque reaction. It will allow the car to go straight if this is done.

My ladder bar setup has just enough preload to make the right rear weigh more when scaled. The car goes very straight on the launch. I had to set it up that way. Can't steer with front wheels in the air. The preload does make it drift slightly to the left downtrack, but that is easier to correct than going right off the line.

And my right rear slick does get hotter than the left.

Later,

David Cole

IP: Logged

capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-11-2002 10:10 AM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
thanks david, maybe the right is supposed to get hotter. but it just seems to me that you would want the rear to have equal downward pressure when you launch, for better traction. same pressure on both tires. here is something weird too. the left side of my rear end squats about 1 1/2 inches more on the left than on the right when i launch. i have tried all kind of combinations of air bag pressures with no change. i have air bags on both sides.
keep those cards and letters coming in friends!!! hee hee

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

Just Strokin
Gearhead

Posts: 754
From: Tuscaloosa, Alabama
Registered: Dec 2001

posted 03-11-2002 10:47 AM     Click Here to See the Profile for Just Strokin   Click Here to Email Just Strokin     Edit/Delete Message   Reply w/Quote
Theoritically both tires should get the same temp (real world?). And in actually your right rear tire heat may becoming from the tire spinning down the strip instead of the heat generated by the burn-out.

You can try to compensate for this in a few ways or a combo of them. Even thought on the pricey side, a good set of scales to weight the car on all 4 corners can help a lot in chassis tunning.

1) Add a leaf to the right rear springs if leafs or a large spring coil spring if coils

2) add adjustable shocks, soften the left shock rebound and tighten the right rear shock compression.

3) if coil-over shocks with adjustable spring pads, preload the right rear shock.

A good investment is the Book mentioned above written by Dave Morgan.

[This message has been edited by Just Strokin (edited 03-11-2002).]

IP: Logged

TomP
Gearhead

Posts: 6120
From: Delta BC Canada
Registered: Dec 99

posted 03-11-2002 01:15 PM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
he ladder bars act as a sway bar, my car launches straight too with the heavy Thunderbolt 2x 3x .125" traction arms. But they still try and twist, ripping the housing upwards on the left tube and downwards on the right tube. I've replaced the housing a couple times and straightened it several times.

Sway bar isn't a bad idea for 4 link cars

IP: Logged

Capri
Gearhead

Posts: 1671
From: Lyons, ILL, USA M&M member #007... the secret agent member
Registered: May 99

posted 03-11-2002 01:18 PM     Click Here to See the Profile for Capri   Click Here to Email Capri     Edit/Delete Message   Reply w/Quote
With mine, We used a heat gun and got pretty much identical het temps on both tires outta the water, and after the run. Do you have a spool in there, or is it still a posi? With the Project Convertible, we still have the posi. If it dont work right, the tire in the more water spins easier, thus getting it hotter due to the more spinning.

Tony

IP: Logged

capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-11-2002 02:21 PM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
my rear end is locked tony. thanks

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

n2oMike
Gearhead

Posts: 2831
From: Spencer, WV
Registered: Jan 2001

posted 03-11-2002 05:32 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
If you did a burnout with a locked rear... and one wheel was in some standing water, and the other was not, the tire on dry land would get a LOT hotter.

Always make sure to get both tires wet, then pull completely out of the water before beginning the burnout. Sometimes it's hard to see, and water gets splashed up past where it is supposed to be.. so sometimes you get crooked burnouts and uneven tire temps.

You might want to check several runs, and see if it heats the tires unevenly on a consistent basis. If it does, you might look into the suspension.

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

IP: Logged

Just Strokin
Gearhead

Posts: 754
From: Tuscaloosa, Alabama
Registered: Dec 2001

posted 03-11-2002 10:50 PM     Click Here to See the Profile for Just Strokin   Click Here to Email Just Strokin     Edit/Delete Message   Reply w/Quote
Still think that your weight transfer is the problem, not the burn out.

After the burn out, does the car launch fairly straight?

IP: Logged

capri man
Gearhead

Posts: 7611
From: doerun, ga.
Registered: Nov 2000

posted 03-12-2002 09:18 AM     Click Here to See the Profile for capri man   Click Here to Email capri man     Edit/Delete Message   Reply w/Quote
yea strokin, it seems to launch pretty straight. the right tire is hotter on every run, not just one time. thanks

------------------
mike r
racing is real
everything else is just a game.
81 capri-7.56 @88mph 1/8
1.56 60 ft.

IP: Logged

Rory McNeil
Gearhead

Posts: 1687
From: Surrey, B.C. Canada
Registered: Nov 2000

posted 03-12-2002 01:36 PM     Click Here to See the Profile for Rory McNeil   Click Here to Email Rory McNeil     Edit/Delete Message   Reply w/Quote
TomP, considering that the car in question is a 81 FOX Capri,"taking off all the shocks" & making a pass could be a real handful, as these cars use struts up front! I sure wouldn`t want to be in the other lane

------------------
78 Fairmont 428 4 speed [email protected]
80 Fairmont 302 5 speed [email protected]
85 Mustang NHRA Stocker under construction, 302 5 speed

IP: Logged

All times are ET (US)

next newest topic | next oldest topic

Administrative Options: Close Topic | Archive/Move | Delete Topic
Post New Topic  Post A Reply
Hop to:

Contact Us | Mustangsandmore Front Page

Copyright 2005, Steve LaRiviere. All Rights Reserved.


Ultimate Bulletin Board 5.47d

Amazon Honor System Click Here to Pay Learn More

[Build a free Mustangsandmore.ws Home Page!]

[Posting Pictures]

[About M&M][Acronyms][Calendar][Chat][Classifieds] [Members' Pics]

[M&M Conventions] [M&M Mug Shots]

[ Mustangsandmore.com Bookstore] [ Smokin' Fords] [Tech Articles]