OMG Lowered and Lightened 2001 Edge Extended Cab

[Blown]

Ok, now that you've actually stated your goal clearly, let's examine the situation. I agree that reducing weight behind the rear axle will reduce the pendulum effect. You are correct there. What you've done should reduce the pendulum effect. Congrats!

The problem in my eyes, is that the pendulum effect you are trying to reduce only happens AFTER the rear has lost traction and you begin to oversteer. Whether it happens in snow, or not, your traction has to be lost in order for what you've done to work. What I'm suggesting, would allow you to keep traction longer, and avoid overrsteering in the first place. You solution is a reaction to a problem. My suggestion, would prevent the problem from occurring in the first place, by aiding traction/grip in the rear.

From your earlier post:
"As shown in the chart to the right, the farther that weight gets from the centerline of the vehicle, the more the vehicle resists direction changes."

You've moved the weight (center of mass) forward, ever so slightly, which has made the vehicle more resistant to directional changes. That's not helping your handling. That's what everyone here has been saying. They're not just 'jumping in on my thoughts', they understand the science behind it.

I'll repeat myself from earlier. It's your truck. IF you're happy with it, then just be happy. Who cares what math and science say? But, beware the placebo effect that modding can have. Many times, we think all of our hard work has made an improvement when it actually hasn't.

Finally, I'm not just standing on the sidelines here. You can see my truck. It's designed primarily for handling/grip. If you want to see what my 'crazy theory of weight distribution' does for handling lets go autocross sometime. My blown 3.0 against your blown 4.0. I'll even put some sandbags or something behind the rear axle.

Jeez are you a piece of work and a PIA. You are wrong again! I never wrote that center of mass is not the biggest concern in handling of a truck. Ya it's heavy in the front, we all know that, Mr. Obvious. You are stuck on that one variable. It is probably one of the largest variables in handling of a truck. But that has very little to do with reducing the polar moment of inertia and that force is there regardless of weather the tires break traction or not!

I would gladly take you after I am done working on it and make you look like a fool, spun-out with two hundred pounds of sand at the tailgate!

You are not making sense and called me out here based on your misunderstanding. I don't get you man. I would be offering-up an quick apology, admitting my mistake, not fueling the fire and calling a guy out as if I don't know what I am doing.

I'd rather you bow-out of this thread, but instead, I am going to. The thread is all screwed-up now and focused on one thing that you sir have got wrong!

I got a gain in handling/cornering by reducing the polar moment of angular inertia at the rear of my truck. A concept which is explained by the laws of physics and many others practical experience. I followed the laws and their lead.

 

[bobbywalter]

Jeez are you a piece of work and a PIA. You are wrong again! I never wrote that center of mass is not the biggest concern in handling of a truck. Ya it's heavy in the front, we all know that, Mr. Obvious. You are stuck on that one variable. It is probably one of the largest variables in handling of a truck. But that has very little to do with reducing the polar moment of inertia and that force is there regardless of weather the tires break traction or not!

I would gladly take you after I am done working on it and make you look like a fool, spun-out with two hundred pounds of sand at the tailgate!

You are not making sense and called me out here based on your misunderstanding. I don't get you man. I would be offering-up an quick apology, admitting my mistake, not fueling the fire and calling a guy out as if I don't know what I am doing.

I'd rather you bow-out of this thread, but instead, I am going to. The thread is all screwed-up now and focused on one thing that you sir have got wrong!

I got a gain in handling/cornering by reducing the polar moment of angular inertia at the rear of my truck. A concept which is explained by the laws of physics and many others practical experience. I followed the laws and their lead.

well, i dont agree that your interpretation of the laws physics as described would improve the time of that vehicle in a specific autocross course i have run on. you obviously feel by the seat of your pants that you have made a great improvement, and likely with your driving preferences and perceptions of how you would like the truck to handle, you have improved handling to your tastes.

there are many types of competitive rbv vehicles and drivers on this forum. quite a few do the autocross thing.

that said, i do have limited experience with the rbv in autocross type performance, but i have quite a bit of experience setting them up.


i am comfortable enough to say this....from actual experience and not some armchair bullshit opinion.

as is....to the point your truck exists right now with your given modifications.

with the course i have in mind.

i would add weight to the truck....and it would be behind the rear axle....

and i will beat you with your own truck at the course, or rather the course setup i am referring to.

and specifically because of the physics you refer to.

 

[stmitch]

Weight behind the rear axle does increase the "pendulum" effect before it breaks loose too, my brother's '68 VW is far easer to oversteer with than just about anything else I have driven considering it lacks the power to break the tires loose on its own. The engine (as massive as a magnesium 1600cc flat 4 is) is essentially hanging off the back end of the car.

However his stock Mustang has almost a perfect 50/50 weight balance (like most sporty cars) and will almost pull a full G on a skidpad.

Oversteer is caused by a loss of grip in the rear. That loss of grip can come from overpowering the tires, or it can come from a lack of quality traction, either due to hard tires, a lack of contact patch, or poor road conditions/snow/etc. This is what I was trying to convey to the OP. He has a supercharged 4.0, with some fairly skinny tires that would be easily overwhelmed. He's trying to limit the severity of his oversteer after it occurs, but having more weight acting on the rear tires would increase the grip the tires provide and prevent the oversteer from happening so frequently in the first place. Increasing his rear contact patch, and upgrading to a stickier tire compound probably would've made a huge difference for him. He chose a different method, and seems happy with it. I'm done trying to convince a happy guy that he shouldn't be happy.

If your brother's VW has anything close to the hard, narrow stock tires, then they may actually lose grip and slide before they "break loose" due to power. This still causes oversteer, but it's because of a lack of grip.

 

[Blown]

My little auto cross friends are clueless. All you have to do is google "pics autocross trucks" and find that most of them are not running a rear bumper and many have removed the tailgate. Simple improvement..........................used by most and would help handling for any dipshit that hasn't taken advantage a proven concept.

You guys have blown-up my post, piss off, and when did it become about you and your auto cross? I wanted and got a bit better handling for what I use my truck for. I will likely write-up some more of my improvements in another post here and you can come over there and profess your knowledge and pick it apart.

 

[stmitch]

My little auto cross friends are clueless. All you have to do is google "pics autocross trucks" and find that most of them are not running a rear bumper and many have removed the tailgate. Simple improvement..........................used by most and would help handling for any dipshit that hasn't taken advantage a proven concept.

You guys have blown-up my post, piss off, and when did it become about you and your auto cross? I wanted and got a bit better handling for what I use my truck for. I will likely write-up some more of my improvements in another post here and you can come over there and profess your knowledge and pick it apart.

I just googled images of 'autocross truck'. The only guy not running a rear bumper or tailgate has a big heavy fuel cell sitting right behind the axle,mthank is clearly visible. They all relocate weight from the front, and move it to the rear. Things like batteries, fuel cells, and radiators all get placed in the rear to improve weight balance and rear grip. So that kind of blew up in your face.
By all means though, post some more of your amazing knowledge, and continue to "school" us about how physics work differently where you're from than anywhere else. I'm having a great time picking it apart.

 

[Blown]

Here is a fine example:

 

[stmitch]

Dude, you're killing me.
That truck has an IRS, and not a solid axle with leaf springs. It's a totally different scenario. That is much less likely to oversteer in the first place.
That truck has a fuel cell behind the rear end.
That truck has a battery and coolant reservoir that was relocated to the rear for better weight balance.
That truck has super wide, super sticky tires for as much grip/traction as possible.
Oh, and it has a tailgate and a steel roll pan.

Please take the time to watch this episode, that shows everything I'm talking about. The good stuff about the rear of the truck starts about 10 minutes in, but the whole thing is educational:
http://www.powerblocktv.com/episode...on-design-driveline-installation#.VGeSwYg8KrU

If they were so concerned with eliminating weight behind the axle, then why did they go to so much trouble and expense to put it all back there? The entire purpose was to improve the front to rear weight balance of the truck,mand that's what they say in the video.

 

[bobbywalter]

hmmmm.

1st. i am not looking to offend you. what i have stated is in complete experienced based opinion that i see as supported by your metrics.


2nd, i am serious about the first point. i myself have been schooled with my own vehicle by others when i thought i was interpreting things correctly... and have always appreciated the advice and lessons.

i have competed in truck pulls, tough trucks, several sub class rock crawl and trail events, track racing, mud racing, drag racing and sand racing and lots of crazy trail stuff...with the same truck in various forms along with many others...but i do have one platform constant over 20 plus years.

been humbled by others at everything in one form or another along with awed.


that picture you put up with a altered wb ranger with a heavier then stock frame(especially in the rear section) is going in the opposite direction of what you state will work only helps my view.



simply put. you loosened the chassis up doing this.

My little auto cross friends are clueless. All you have to do is google "pics autocross trucks" and find that most of them are not running a rear bumper and many have removed the tailgate. Simple improvement..........................used by most and would help handling for any dipshit that hasn't taken advantage a proven concept.

You guys have blown-up my post, piss off, and when did it become about you and your auto cross? I wanted and got a bit better handling for what I use my truck for. I will likely write-up some more of my improvements in another post here and you can come over there and profess your knowledge and pick it apart.

there are chassis weights bolted to those trucks that are not in the pictures, usually much heavier then the bumpers and tailgates.......at least the trucks i have seen, worked on and driven.


going and getting some free scrap light weight crating for 4 wheelers from a motorcycle/snowmobile dealer and cutting that up to brace up the chassis and adding poly spring bushings and body/front suspension bushings will do a much better job in the handling department.

making bed braces and things of that nature and centering up the fuel capacity goes a long way towards improving handling. the oem fuel tank is on the drivers side. the shocks are staggered....theres so many easy fixes to the platform to improve handling besides weakening the already flexy rear frame rail situation that are basically free and add little or no weight over all i am shocked you could think what you did was a good idea.


i only offer the autocross idea as a measuring stick of how any modification is measured.

maybe just a g pad test would be simpler....but just like the picture you posted, the work is only justified and proven at the track.