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Weight balance and scaling set up

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jay45dee said:
not a chance. Only by physically taking weight off the nose or adding ballast to the rear.
Unless is it has stock car style weight jackers and of course it does not.

This confirms my suspicion. Even stock cars cannot alter front / rear weight distribution significantly by adjustment. They are adjusting cross weight and corner balance. Ballast is the only real way to improve net distribution. And that only really applies if there is a minimum weight limit in something you are doing.

The good news is you don't need to think too hard about your target. The mustang platform has too much front weight and will benefit from moving as much as you can toward the rear.
 
Look, I know you can not alter front/rear weight percentages very much by the shocks and or shock jacks, I never implied that's how we were going to do it. Changing the ride height of each corner of the car will factor weight on the opposite wheels but this is far from the point of my questions. I am just looking for a good rear weight percentage for the Mustangs. Every car is different and it varies depending on horsepower but if all the Boss guys had a good reference point for these cars, it would help give us a starting point when it goes to the scales to start moving weight around. Not really going to argue this point about shocks altering front/rear weight any longer.

As far as being under class weight, no. The American Iron Series has a power to weight ratio rule and allows up to 300lbs of ballast so we should be fine to make the rules.
 
jay45dee said:
Look, I know you can not alter front/rear weight percentages very much by the shocks and or shock jacks, I never implied that's how we were going to do it. Changing the ride height of each corner of the car will factor weight on the opposite wheels but this is far from the point of my questions. I am just looking for a good rear weight percentage for the Mustangs. Every car is different and it varies depending on horsepower but if all the Boss guys had a good reference point for these cars, it would help give us a starting point when it goes to the scales to start moving weight around. Not really going to argue this point about shocks altering front/rear weight any longer.

As far as being under class weight, no. The American Iron Series has a power to weight ratio rule and allows up to 300lbs of ballast so we should be fine to make the rules.
Here's how mine looks FWIW. Here's the thread on weight reduction where I copied it from: https://trackmustangsonline.com/index.php?topic=496.200

Corner weighed the Boss today with a FULL tank of gas:

With Driver
LF 1068 RF 976
LR 874 RR 818
Total 3736

Front 54.71%
Rear 45.29%

Left 51.98%
Right 48.02%

Cross LF/RR 1886 lbs 50.48%
Cross RF/LR f1850 lbs 49.52%

Weight without driver is 3559 lbs and with half tank of gas approximately 3499 lbs.
 
Awesome Thanx Cloud9!

That's what I was looking for. Just wanted to know what percentages everyone is at and how it is working for them.
 

JScheier

Too Hot for the Boss!
cloud9 said:
Front 54.71%
Rear 45.29%

[quote author=JScheier]50/50 is usually the ideal number that people shoot for. With an aftermarket K-member and engine setback, you might get close. Usually 52-55% of the weight up front is S197 territory... use that as you will.[/quote]

....missed it by that much... ;)
 
jay45dee said:
Look, I know you can not alter front/rear weight percentages very much by the shocks and or shock jacks, I never implied that's how we were going to do it. Changing the ride height of each corner of the car will factor weight on the opposite wheels but this is far from the point of my questions. I am just looking for a good rear weight percentage for the Mustangs. Every car is different and it varies depending on horsepower but if all the Boss guys had a good reference point for these cars, it would help give us a starting point when it goes to the scales to start moving weight around. Not really going to argue this point about shocks altering front/rear weight any longer.

As far as being under class weight, no. The American Iron Series has a power to weight ratio rule and allows up to 300lbs of ballast so we should be fine to make the rules.

Just remember, if you run ABS, you'll be at 9.5:1. I got down to 3430 with me and now I'm adding weight to keep from restricting my motor too much. I'm currently at 368 HP for a min weight of 3496 lbs. I want to be at 375 and 3562.
 
I run without ABS so I need to be 9.0:1
I am at roughly 425 rwph so 3,825 lbs would be the weight limit. Since that is way heavier then the car will be even with the allowed 300lbs of ballast I will end up de-tuning the engine.
 
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1
To continue the discussion (on front-end setup, rather than scaling), did you have a roll center relocation kit done up front?
Actually, before you answer that question:

1) Where are you experiencing understeer? Entry/Mid/Exit?
2) Under what conditions is the push showing? On throttle/off throttle/modulated throttle/on brakes etc
3) What kind of corner causes the push to be at its worst?
4) Do you have a in-car video (that shows your steering inputs as well) that shows this?
 
boro92 said:
To continue the discussion (on front-end setup, rather than scaling), did you have a roll center relocation kit done up front?
Actually, before you answer that question:

1) Where are you experiencing understeer? Entry/Mid/Exit?
2) Under what conditions is the push showing? On throttle/off throttle/modulated throttle/on brakes etc
3) What kind of corner causes the push to be at its worst?
4) Do you have a in-car video (that shows your steering inputs as well) that shows this?

Taller ball joints and bump steer kit along with adjustable upper strut mounts. Although Steeda just came out with new ones this week that allow for much more caster and camber adjustment so I will be ordering a set of those to try out.
1 - Mid corner. The car is great in turn in and exit.
2- rolling the center just after braking
3- tight apex low speed corners. and mid corner on high speed corners.
4- yes the video shows a lack of front grip mid corner.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
Mid turn push has always been the issue on these cars. I can't solve it for you, but I have coped with it by rotating the rear or adjusting my line to make a sharper and shorter turn, with a more open apex and exit.

To accomplish the rotating, I employ throttle steering or trail braking.

Aside from driver changes, I would guess a harder rear away setting would help it rotate?
 
pufferfish said:
Mid turn push has always been the issue on these cars. I can't solve it for you, but I have coped with it by rotating the rear or adjusting my line to make a sharper and shorter turn, with a more open apex and exit.

To accomplish the rotating, I employ throttle steering or trail braking.

Aside from driver changes, I would guess a harder rear away setting would help it rotate?

Solid advice...

I'm hoping this won't sound rude, but a driver mod could pay huge dividends..

Practice doesn't always make perfect, but just when I think I'm hot stuff someone else comes along and smokes me.

My 2HP
 
I definitely agree with the braking technique changes to help rotate the car in the center. I am learning GT cars after 15 years road racing karts. I have a lot to learn yet about these things but I will get it figured out. Never had problems adapting to anything else. Seat time is all it takes.
 
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1
I wanted to shy away from driving style/driving inputs etc as this is a setup thread...but lots of good advise was given pertaining to that!
Regarding mid corner push - this would mean that the car is pushing as soon as the suspension "takes a set". That is, you've got the car pointed in, all the weight transfer has occurred and is completed--and now the suspension is loaded.

I dont feel that most changes to geometry is going to alter this behavior, and although corner balancing will help and is a good place to start (esp it hasnt been done already--it needs to!), it would otherwise suggest a spring issue. Changing rebound/bump isn't going to help much either. This is one of those cases where you want to play with sways (stiffen the rear/soften the front) or springs.

Whichever is easier/already available to you, start there first. But mid-corner really narrows it down...so that's a good starting point.
 
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VTBoss302 said:
Might have to agree to disagree on this one...

:p

;)

Foot in mouth. You're right.
Back tracking...I would state that geometric changes would have a lesser relative effect during mid corner balance when compared with any gains you'd see on entry or exit. But yes, mid corner you're going to want to deal with ackerman (i guess via fudging with toe) and camber. IIRC OP has -2? Is that right?

Edit - I still stick with my guns and would start with spring rates/sway bars :)
 
6,363
8,189
Just a couple of ideas, if you do scale the car, keep a set of "set up"wheels and tires just for the scaling process. keep "X" amount of nitrogen in them and don't use them for anything else, don't temperature compensate them either, you need "X" amount of air since tires act as springs..it should never change.
Don't be afraid to use the smallest rear sway bar known to mankind, even experiment with taking it off.
Don't fall into the trap of "tightening" the front end to reduce a push condition, instead "loosen" the rear of the car.
I'm pretty well convinced at this point the only good, dependable, repeatable, fully adjustable shocks are a set of $8K Penskes...unfortunately. IMO anything else is a crapshoot, I really, really wish that wasn't true.

Slow cars always handle.
 
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blacksheep-1 said:
I'm pretty well convinced at this point the only good, dependable, repeatable, fully adjustable shocks are a set of $8K Penskes...unfortunately. IMO anything else is a crapshoot, I really, really wish that wasn't true.

Sigh. I wish this wasn't true too :( :(
After only 15 minutes of lapping, the factory shocks are really hot to the touch. Call me a noob, but I didn't expect them to heat up that swiftly! Wow!
 
blacksheep-1 said:
Just a couple of ideas, if you do scale the car, keep a set of "set up"wheels and tires just for the scaling process. keep "X" amount of nitrogen in them and don't use them for anything else, don't temperature compensate them either, you need "X" amount of air since tires act as springs..it should never change.
Don't be afraid to use the smallest rear sway bar known to mankind, even experiment with taking it off.
Don't fall into the trap of "tightening" the front end to reduce a push condition, instead "loosen" the rear of the car.
I'm pretty well convinced at this point the only good, dependable, repeatable, fully adjustable shocks are a set of $8K Penskes...unfortunately. IMO anything else is a crapshoot, I really, really wish that wasn't true.

Slow cars always handle.
Any thoughts on AST?
 

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