Login    Forum    Search    FAQ

Board index » Racing Forum » Drive Train, Suspension and Brakes




Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject:
 Post Posted: Tue May 02, 2006 8:29 pm 
Offline
User avatar

Joined: Tue Apr 18, 2006 7:03 am
Posts: 1444
Tray, yes you should have to lengthen the upper left bar to get the bolt out. Get it loose, top off the fuel cell and sit in the seat and get someone else to get it set to neutral again and then shorten the bar up by 1-2 flats.

And then I would have to plot it out to verify where the IC is and where it is going. There is a program out there called " 4 link wizard " I think it is and it makes it much easier to figure out.. for about 100 $


Or you could just move bars around and get it sooner or later


Top 
 Profile  
 
 Post subject:
 Post Posted: Tue May 02, 2006 8:33 pm 
Offline
User avatar

Joined: Thu Apr 20, 2006 8:57 pm
Posts: 708
Gothcha....I was gonna do the checking on my alignment rack...that will work,,wont it?suspension will be at rest,,I'll just throw a few weights in the seat...and raise it up... =; then adjust...

_________________
Image

THE ATOMIC BANEGA(BANANA/VEGA)
http://www.youtube.com/watch?v=0BagEEa8JDo


Top 
 Profile  
 
 Post subject:
 Post Posted: Tue May 02, 2006 8:35 pm 
Offline
User avatar

Joined: Thu Apr 20, 2006 8:57 pm
Posts: 708
Yeah,,I'm gonna get the book...4sure...Thanks Duane...Lots to learn...Laters..

_________________
Image

THE ATOMIC BANEGA(BANANA/VEGA)
http://www.youtube.com/watch?v=0BagEEa8JDo


Top 
 Profile  
 
 Post subject: 4 link on paper
 Post Posted: Wed May 03, 2006 7:30 pm 
Offline
User avatar

Joined: Wed Apr 19, 2006 4:25 pm
Posts: 422
Location: Beaverton Ontario Canada
Hello
I would like to know more about setting up the car on paper. I had e-mailed Bubstr and he was kind enough to send me a drawing, but it is small and my eyes aren't that great anymore
I would like to know how to figure out the vertical ht for the center of gravity
BTW Tray, I love your wagon.......nice pics from underneath as well
neat car
Tom


Top 
 Profile  
 
 Post subject:
 Post Posted: Wed May 03, 2006 9:40 pm 
Offline
User avatar

Joined: Tue Apr 18, 2006 9:54 pm
Posts: 1619
Location: Western Illinois
Here is that drawing. Maybe someone can enlarge it. I used to have the formula for center of gravity hight, but can't find it for the life of me. You had to scale the car, then jack chassis up to a givin angle and scale the grounded end again,. using ratio/proportion problem you find new center of gravity. with them 2 point ctr gravity and new center of gravity with given angle find hight with simple geometry. Now since I've been out of school longer than some here are a live I can't seem to remember the formulas. Any math wizards here that could help? [img][img]http://i34.photobucket.com/albums/d103/Bubstr/4linkdrawing.jpg[/img]
Small eh[/img] That's worth 25% of your grade for this quarter lol

_________________
Older I get the less I know for sure Dennis


Top 
 Profile  
 
 Post subject: Hi
 Post Posted: Sat May 06, 2006 10:37 pm 
Offline

Joined: Sun Apr 30, 2006 6:20 am
Posts: 357
Location: Wodonga, Australia
Hi Tray

I have spent the last 2 months full time on learning about 4 links and trying to set them up so they work.
One thing i would never do now is pre load a 4 link until you have ran it and seen what it does with out pre load.
Pre load from what i have learnt is used to fix up minor chassis problems such as not being square to the front suspension points.

I may be telling you to suck eggs but maybe not

1. make sure both bottom bars are exactly the same length.
2. remove one of your top bars completely.
3. Get the remaining top bar and use it to adjust your pinion angle
4. then fit the other top bar making sure it slides in easly so u arent pre loading anything.

Anyways Tray, your ic is too far forward by that video

You should plot it out on the ground.

measure from the ground to you lower 4 link mount on and then from the floor to the upper 4 link mount.

This now gives you a chalk mark on the ground for your rear points.

Now do the same for the front points.

Now you can join the lines and find where your instant centre is and according to my guess it must be somewhere near the front wheels or even further forward.

To start you must have your bottom bar level with the ground, then angle your top bar down at the font to get your ic roughtly about the middle of the front door.

_________________
VK Commodore
383 Holden
2 speed Glide
Everthing on this car is all done by myself
650 HP Plus 300 Nos
Best so far
1.38 60 ft, 6.3 1/8 at 110 mph and 10.2 at 135 mph, long way to go before i reach my low nine hey


Top 
 Profile  
 
 Post subject: Re: Hi
 Post Posted: Sun May 07, 2006 10:52 am 
Offline
User avatar

Joined: Tue Apr 18, 2006 7:03 am
Posts: 1444
Clinker wrote:
Hi Tray

I have spent the last 2 months full time on learning about 4 links and trying to set them up so they work.
One thing i would never do now is pre load a 4 link until you have ran it and seen what it does with out pre load.
Pre load from what i have learnt is used to fix up minor chassis problems such as not being square to the front suspension points..


I'm going to have to respectfully disagree with this reasoning for preload. I have learned that is used to off set the torque created by the engine and driverline. Same reason an air bag might be used in the right rear only of a stock framed car.

I am by no means a pro at this as by myself I have only backhalfed 3 cars, all 4 links and all 3 got 2 flats of preload and all 3 went dead straight on their first passes. And I will gaurantee that all 3 were less than 1/16" of being out of square with the frame and the front suspension.

You know those stock framed, suspension cars that leave with the Left front 3' in the air and the right front barely off the ground ... a little preload ( air bag or ?? ) will stop that.


Top 
 Profile  
 
 Post subject:
 Post Posted: Sun May 07, 2006 12:00 pm 
Offline
User avatar

Joined: Tue Apr 18, 2006 9:54 pm
Posts: 1619
Location: Western Illinois
I have to agree with duane. the preload is for chassis torque control. when you shorten that right top bar, it raises the front mounting points on that side and puts more anti squat in that side, increasing the contact presure of that tire and preventing that side to squat. Anytime your mounting points change you change your instant center. That's why it is a good idea to map out several variables on a drawing so you know what the changes are likely to do. What happens when you go to a new strip, it's got no concrete and the only time it seen traction compound was when someone put some on their slicks? We all of a sudden need more bite, hey i have a setting for that in the tool box. then you go to one that feels like you walking on flypaper. You got a set up for that too, in the box.

_________________
Older I get the less I know for sure Dennis


Top 
 Profile  
 
 Post subject: Hi
 Post Posted: Sun May 07, 2006 6:06 pm 
Offline

Joined: Sun Apr 30, 2006 6:20 am
Posts: 357
Location: Wodonga, Australia
Duane and Bubstr

You guys are right and i totally agree with you on the torque reaction of the driveline.

BUT LOL

What you are doing when you pre load the top bar is just shortening it by say a 1/4 of a turn. All its doing is placing more weight on that tire, say on a typical sedan its probably adding 50 lbs of pressure onto that tire to compensate for the rotational twist the diff housing is recieving from the tailshaft which is effectively unloading the right rear.

what you guys are doing by pre loading the top bar is adding that 50 lbs of weight back onto that tire which is exactly what you want to do

So yes the bottom line is you are fixing the problem.

I just think the better way to achieve this is to have all the bars neutral and see how it launches, if it does pull to either side then id rather add the battery and fuel pumps to the side that you pre load.

So what do you guys think.

Trev

Oh and by the way, you guys dont know me well, so please dont think im being a smart ass, Im all in for constructive critiscism and comments so i can learn and if i have something usefull i can pass it on.

_________________
VK Commodore
383 Holden
2 speed Glide
Everthing on this car is all done by myself
650 HP Plus 300 Nos
Best so far
1.38 60 ft, 6.3 1/8 at 110 mph and 10.2 at 135 mph, long way to go before i reach my low nine hey


Top 
 Profile  
 
 Post subject:
 Post Posted: Sun May 07, 2006 6:19 pm 
Offline
User avatar

Joined: Sun May 07, 2006 10:04 am
Posts: 1015
Location: nw ohio
hey trey,

pm me and i can get you some info on a 4link program that you can have for free...

i use the jerry bickle book "complete guide to chassis preformance". best 70 bucks i ever spent. you can order it here https://secure1.securehosting.us/jerryb ... n%20Center

a long ic point pitch rotates (transfers the weight) to the rear slower and for a longer amount of time than a short one. so if you want the car to be less agressive, you need a longer ic. if you want to stand it on the bumper (which you said you didn't) then you want a short one.

equally important is how high the ic of the ground. this matters because of the placement of the neutral line. the longer the ic the higher it should be off the ground.

this is where that program come in handy. all you need to do is set the car at ride height and measure you hole location. it does the math and plotting for you.

i hope this may clarify some things for you.... i will try to help as much as possible. i fought w/ the 4-link on my car to try to figure it out. then i got the bickle book and it all makes sense now!!!

let me know if i can help. :-k

_________________
Image


Top 
 Profile  
 
 Post subject: Re: Hi
 Post Posted: Sun May 07, 2006 8:25 pm 
Offline
User avatar

Joined: Tue Apr 18, 2006 9:54 pm
Posts: 1619
Location: Western Illinois
Clinker wrote:
Duane and Bubstr

You guys are right and i totally agree with you on the torque reaction of the driveline.

BUT LOL

What you are doing when you pre load the top bar is just shortening it by say a 1/4 of a turn. All its doing is placing more weight on that tire, say on a typical sedan its probably adding 50 lbs of pressure onto that tire to compensate for the rotational twist the diff housing is recieving from the tailshaft which is effectively unloading the right rear.

what you guys are doing by pre loading the top bar is adding that 50 lbs of weight back onto that tire which is exactly what you want to do

So yes the bottom line is you are fixing the problem.

I just think the better way to achieve this is to have all the bars neutral and see how it launches, if it does pull to either side then id rather add the battery and fuel pumps to the side that you pre load.

So what do you guys think.

Trev

Oh and by the way, you guys dont know me well, so please dont think im being a smart ass, Im all in for constructive critiscism and comments so i can learn and if i have something usefull i can pass it on.
No problems here with crititiscism, Trev. As long as we are nice about it, I think it helps everyone. I've been wrong before, and fooling with dirt track cars will warp your mind. lol But in this instance yes we put a few more pounds on right rear, but as we did that it changed the hieght of the front mounting point, which will elevate the instant center on that side, which means more antisquat, which means more down presure. What do you think? You have a valid point about the static weight being set to your advantage. Now I expect you to prove me wrong, this is what bench racing is all about, it's an exchange of ideas. If there is a better way to do it there is the winner,all of us.

_________________
Older I get the less I know for sure Dennis


Top 
 Profile  
 
 Post subject: Re: Hi
 Post Posted: Sun May 07, 2006 8:43 pm 
Offline
User avatar

Joined: Tue Apr 18, 2006 7:03 am
Posts: 1444
Clinker wrote:
Duane and Bubstr

You guys are right and i totally agree with you on the torque reaction of the driveline.

BUT LOL

What you are doing when you pre load the top bar is just shortening it by say a 1/4 of a turn. All its doing is placing more weight on that tire, say on a typical sedan its probably adding 50 lbs of pressure onto that tire to compensate for the rotational twist the diff housing is recieving from the tailshaft which is effectively unloading the right rear.

what you guys are doing by pre loading the top bar is adding that 50 lbs of weight back onto that tire which is exactly what you want to do

So yes the bottom line is you are fixing the problem.

I just think the better way to achieve this is to have all the bars neutral and see how it launches, if it does pull to either side then id rather add the battery and fuel pumps to the side that you pre load.

So what do you guys think.

Trev

Oh and by the way, you guys dont know me well, so please dont think im being a smart ass, Im all in for constructive critiscism and comments so i can learn and if i have something usefull i can pass it on.



Trev ... I too didnt take any offense or looked at your response of critisicism. Like Bubstr said .. this is all bench racing and to bounce ideas off of each other.

And your exactly right in what the preloading is doing.

In the case of my 64 which I backhalfed w/ a 4 link I already had one battery and the fuel pump and filter on the right side. On most cases I try to mount the battery's dead center at the rear.

Which ever way we choose to do this as long as we both get down the track nice and straight thats what really matters.


Top 
 Profile  
 
 Post subject:
 Post Posted: Mon May 08, 2006 11:18 pm 
Offline

Joined: Sun Apr 30, 2006 6:20 am
Posts: 357
Location: Wodonga, Australia
Hi

Bubstr, what about if we set the rear end up neautral, put the battery in the right rear and move the fuel tank slightly to the right as well.

then weigh each side of the rear and try and end up with say 50 lbs extra on the right side.

Then to compensate for the slightly lower ride hight we screw the coil over adjuster nuts up one or two turns to bring the ride height up.

To both Duane and Bubstr, yes in reality it doesnt matter which way you do it hey, as long as the car runs true and launches good.

Maybe we could do some track testing and compare the differences, I cant cause my driving skills are crap lol, and my runs are always 3 or 4 tenths out anyway.

Trev

_________________
VK Commodore
383 Holden
2 speed Glide
Everthing on this car is all done by myself
650 HP Plus 300 Nos
Best so far
1.38 60 ft, 6.3 1/8 at 110 mph and 10.2 at 135 mph, long way to go before i reach my low nine hey


Top 
 Profile  
 
 Post subject:
 Post Posted: Tue May 09, 2006 1:00 am 
Offline
User avatar

Joined: Tue Apr 18, 2006 9:54 pm
Posts: 1619
Location: Western Illinois
Clinker wrote:
Hi

Bubstr, what about if we set the rear end up neautral, put the battery in the right rear and move the fuel tank slightly to the right as well.

then weigh each side of the rear and try and end up with say 50 lbs extra on the right side.

Then to compensate for the slightly lower ride hight we screw the coil over adjuster nuts up one or two turns to bring the ride height up.

To both Duane and Bubstr, yes in reality it doesnt matter which way you do it hey, as long as the car runs true and launches good.

Maybe we could do some track testing and compare the differences, I cant cause my driving skills are crap lol, and my runs are always 3 or 4 tenths out anyway.

Trev
yes if you put 50 more pounds on right rear that should increase the tire contact presure, but then we will have more squat to control on the right rear, and also we have just stored 50 extra pounds of energy in that spring. It will give it back to us when we hit the brake. A little bit is tolarable but to much will pitch the car down on left front when stopping. I prefer the preload and increased anti squat on right side because it does it's job when we need it, controls the squat and has little effect at other times.

_________________
Older I get the less I know for sure Dennis


Top 
 Profile  
 
 Post subject:
 Post Posted: Tue May 09, 2006 7:37 am 
Offline

Joined: Sun Apr 30, 2006 6:20 am
Posts: 357
Location: Wodonga, Australia
Yes we have put 50 extra pounds in the rear, but thats exactly the same as when we preload a bar, also by adjusting up the bottom nuts on the shocker how does it store more energy in the spring, when using then bottom adjusting nuts you are simply raising the seat position of the spring and the top spring mount raises as the shocker raises.

Both methods are really doing exactly the same thing, its really personal preference i suppose.

Trev

_________________
VK Commodore
383 Holden
2 speed Glide
Everthing on this car is all done by myself
650 HP Plus 300 Nos
Best so far
1.38 60 ft, 6.3 1/8 at 110 mph and 10.2 at 135 mph, long way to go before i reach my low nine hey


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 33 posts ]  Go to page Previous  1, 2, 3  Next

Board index » Racing Forum » Drive Train, Suspension and Brakes


Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron