Help Me Learn...

[180sx]

Hello Forum Members!

First off, Happy Holidays!

Now then. I'm fairly new to modifying 4x4's. I have been doing some research, and learning all that I can, on top of hanging out with my 4x4 buddies more instead of my road race/drift/drag/autocross/rally/all of the above friends to help my quest. This is all fine and dandy, but I don't know exactly where to look for the basics in the mechanical operations. Such as why a solid front axle might be superior to an IFS. And even more basic as to how a solid front works! (I have no idea. I mean, how does it steer, how the links are setup such as a '3-link' setup, and how one goes about choosing the right gear ratio for the front).

Can you kind of understand where I'm coming from? Cars to me is easy, and I've been doing that since I was like 7 years old, so i know the in's and out's. But 4x4's is my new venture. It's like a new 'high' the first time I went with a friend in his blue oval beast. And my 'Taco' buddies let me drive their rigs, and i couldn't explain the rush i felt when i scaled a 60* incline with so much rocks to slowly crawl over, or launching the truck in the air over a ridge only to drive through some deep water hole where the water is up to my thighs, and smiling every minute of it.

I take my modifying seriously, and always try to go the 'hard' route with my choice of vehicles (most of the time! Doesn't include my old 240's and my FD RX-7!). So the R50 kind of stood out to me when I found there was like nothing for it. And Tyler (I belive that's his name) inspired me with his SAS on his R50 (can't wait to hear about it when it's completed finally!) and makes me want to learn all the basics so that maybe some day I can go the same route as him.

SSSSoooooo.......any help in showing me the right direction is appreciated. In the mean time, I will my way to knowledge!!

 

Jose

[tmorgan4]

Always good to see people eager to learn. Unfortunately there is so much more to building a suspension system than anyone is going to tell you in a single post on here that you'll probably learn more by searching various sites that have write-ups on certain topics.

 

My friends have always been into fast cars and I somehow got interested in building inefficient, poor handling, and slow off road cars. I'm actually working on building a few other friends projects for them since then I can have some four wheeling friends whenever I get around to finishing mine.

 

I always hated the idea of IFS and never understood why any companies would build a vehicle with it. It's not until after you drive a car with it (I still haven't driven mine) that you start to realize why Nissan designed our R50s with IFS. Handling with a well designed IFS is so far superior to a well designed solid front axle that you have to decide which aspects of your rig are important to you. I'm trying to design my solid front axle so that it handles well on the road (relatively speaking for a rig on unbalanced bias ply 40s and a lot of lift over stock) but I'm sure it will still never handle like it did stock.

 

Recently I've been introduced to the world of heavy duty long travel IFS systems after a friend of mine asked me to build him a kit for his Tacoma. After studying up on them more a long travel IFS is a great way to build a rig that will handle great on the street but still have suitable travel for moderate four wheeling. Don't think you need to hate your IFS....enjoy it's handling and comfort on the road but keep in mind there are strong options out there. I'm still waiting on parts so hopefully I can have something to show for this soon instead of CAD pictures of what it *should* look like.

 

 

A well designed 4wd long travel (while most are 2wd and are worthless other than the street and the desert) will get in the neighborhood of 13-15" of wheel travel. With my solid front axle I'm getting closer to 40" of wheel travel so you can see a big difference there.

 

You've probably already seen these but unfortunately it's one of the few pictures I have from testing my solid axle.

 

 

Just keep in mind that you're one nice looking Pathfinder will slowly go downhill until it doesn't look nice anymore. It's an expensive hobby since things can go wrong so fast. We were on our way to go four wheeling a month or so ago and a friend rolled his pristine condition FZJ80, and it went from being worth $9000 to $500 in a few seconds.

 

 

It was cold driving it an hour home in 10* weather!

 

 

I've learned a ton over the past 3 years and I sincerely feel that the best way to learn anything is from experience. People will always try and discourage you from modifying an R50 because there's no aftermarket support or because it's a unibody. I just kind of go my own way (if you haven't noticed) and ignore all the people that tell me things can't be done. Feel free if you have specific questions to ask and I'll try and answer as best I can.

Edited December 27, 2008 by tmorgan4

[nissandoms47]

I am not going to lie though, I wish nissan designed some of the other trucks like they do the newer ones. With coilovers in the front. The r50 is for sure unique though.

[MY1PATH]

i'LL give your questions a shot;

 

2 major factors that gives IFS the advantage on the road.

1 each wheel can act by itslef with no infulence on the opposite wheel

2 IFS can be designed to change camber under load allowing more tire srface to remain in contact with the road when cornering or driving on a banked road.

 

Solid axle;

just like a solid rear axle found on all tucks many high power RWD sports cars and some suv's. on each end is whats called a steering knuckle(also ties uper and lower links together on IFS as a common steering component) its pivots right to left while a CV joint or universal on the end of the axle shaft translates this motion thru the center of the knucle to the wheel.

 

A few Advantages, Ususually very strong(ability to run large heavy tires with mininmal consequece), once assembled the only alignment almost never changes(even if you lift it more) the only change that may need messed with would be TOE in which is the simplest to ajust. much greater range of suspension travel available.

Edited December 27, 2008 by MY1PATH

[tekazgtr1984]

I am not going to lie though, I wish nissan designed some of the other trucks like they do the newer ones. With coilovers in the front. The r50 is for sure unique though.

 

Agreed, the R50 is definitely unique. And oh so badass!

As you can see from Tyler's ridiculously incredible custom R50, anything is possible if you're willing to do it. That rig never ceases to amaze and sure proof that imagination goes a long way

[180sx]

OK, Cool. So a 'basic' question. How does a trailing link work? i mean, you have them atached to the frame, then to the axle. but how do they rotate? how do you know how long they are supposed to be? in Tyler's picture, his axle is extreme! but how do those links allow it to twist like that?

one more. What is a traction control bar and what is it supposed to do?

[Fukinitupagain]

IFS aint so bad & you don't have to have ginormous tires to go out & hang with the big boys. 32s & better driving skills will go a long way!

[tmorgan4]

OK, Cool. So a 'basic' question. How does a trailing link work? i mean, you have them atached to the frame, then to the axle. but how do they rotate? how do you know how long they are supposed to be? in Tyler's picture, his axle is extreme! but how do those links allow it to twist like that?

one more. What is a traction control bar and what is it supposed to do?

 

A trailing link, like how people often refer to the rear lower arms as "trailing arms"? Just think of each link as restricting one more degree of freedom of the axle. In my front 3-link setup (and a front non-triangulated 4-link is similar) the three main links (2 lowers, one upper) keep the axle front rotating and an additional panhard/trackbar is necessary to keep the axle located from side to side. In my setup I've got flex joints at the frame side and heims at the axle. They all pivot to keep the links from binding.

 

As far as how long they are supposed to be, there are pros and cons of going longer and shorter. With a longer link they are closer to being flat which is usually a good thing for suspension geometry. A longer link helps protect the underside of the car since you can slide over rocks with them but you lose ground clearance at the same time. You'll get more flex out of longer links, but PLEASE do yourself a favor and don't build a suspension around how much travel it will give. Design it with good suspension geometry in mind and you will have plenty. There are long more pros and cons of suspension link lengths but it would take forever to discuss them all. You just need to find a balance between long and short and they should do the trick. No magic number. Mine lowers are about 38" from bolt hole to bolt hole and the upper is slightly shorter.

 

Are you talking about a traction bar like people use with leaf springs? Some people add in traction bars while using leafs to help prevent axle wrap. I am NOT a fan of leaf springs but a lot of people like them.

[XPLORx4]

What is a traction control bar and what is it supposed to do?

 

As Tyler explained, a traction bar is simply a type of trailing link that bolts to both the frame and the axle (usually the top or bottom of it) in order to control axle wrap on leaf spring suspensions. (A leaf spring not only suspends the axle, it also locates it under the frame.) Axle wrap is caused when lots of torque causes the axle to rotate and twist the leaf springs into an S shape.

 

Axle wrap can also cause wheel hop, resulting in reduced traction, among other things. That's why they're called "traction bars".

 

Read more about axle wrap and traction bars here.

 

FYI, coil sprung suspensions do not need traction bars because, unlike leaf sprung axles, the springs only suspend the axle, while the links locate it under the frame.

[180sx]

Hey guys, thanks for all the great answers. Been doing alot of searching sites myself and found a lot of useful info. My budy accross the street is putting a front axle on his Tacoma, and he is going the leaf spring route with it. And i checked out my neighbors Jeep's front axle set-up. I learbed alot from just looking, and talking to my bud about his swap plans. Only thing is i'm trying to find a front that has coils instead of leafs to go look at.

 

Last question's and i'm full search mode. Gearing. How do you know what gearing you'll need in front? i hear people saying they have, like, 3.77 in back and 4.66 in front, and other varyations. Does it matter exactly what you'll need, or if its off you'll over/under drive the front wheels?

Steering. Tyler, you have full hydro on yours, and it connects on either side to each spindle. I've heard thats 'illegal' on the street. Maybe its just Virginia. But, as from what i can see, most steering set ups have the box connect to one wheel, and a bar go acrros from the wheel to the other wheel to steer. Is this the most common setup? And my bud sys theres also 'hydro-assist' steering. What are yall's thoughts?

Thanks again for all your help.