DIY - IFS rear springs into solid axle rear - Updated

[Gribble]

any news on fitting the 2" IFS springs?? instead of blocking it to give an overal 4" lift. Very keen to do it aswell.

Ive been busy with comitments to the rally team, we got to go to alice on saturday and the car only got finished on sunday night. Most people think its because im lazy, which is true, i am. But ill get it done soon.

[My Lil Lux]

As another option, I've dropped my rear shackle mount down 100mm and back 80mm, and using my old Snake racing extended shackles, with this I've kept a 45 deg angle and I can put my standard shackle back in if I need to, I also run a 75mm dropped front hanger moved 2" forward with 2" lifted OME rears and standard length shackle in the front, basically did this as I intend to put standard rears in front and pull out the extended shackles in rear, and put back in standard, haven't gone to engineer yet , so can't say the legality of it.

[eliteforce32]

cris was also running lif blocks in the arse to

[-Richo-]

I know Roc7toy was using 2" old man emu IFS springs in the Roctoy, Maybe Stumpy still has these.

The pair i used came from this rig, they arent 2" lifted. If they are they have sagged 2". Mine sits lower than it did stock now but the leaf pack was short 2 leaves. Im awaiting an IFS rear diff housing/axle and will be adding small blocks (18mm) to compensate for the missing leaves, u bolt flip and trac bar.

[ingthorsson]

Those IFS rear springs seem to be a good idea. They must be extra soft when used with stock shackle mounts because of the extreme angle of the shakles: the vehicle literally drops down onto the spring as the spring straightens out.
My two bit worth opinion here is more about the so called "track bars" you guys down under seem to favor. But hey! I´m not putting them down: if they work and your´e happy with them, it´s all to the good.
Scientific suspension THEORY on the other hand would call that a "single ladder bar" as it is solidly mounted onto the axle.
A true track bar is simply a rod, mounted by heim joints or shock bushings at ONE point on the axle; a bracket extending maybe some 5 or six inches above axle centerline, and at ONE point on the frame.
Again, scientific suspension THEORY says that there really is only one right position for this frame mount if you want to avoid suspension binds. That point is on an imagined line that goes between the eyes of the spring, two thirds of the way from axle centerline to the forward spring-eye. That point, or line going across the vehicle, is the instant center of axle movement with leaf springs, i.e. the point around which the axle moves.
This is theory, people have been using longer track bars for ages without suffering unduly from suspension binding. The best front placement for any traction aid would be at the center of gravity point which in most cases is far in front of the rear springs.
A true track bar should both prevent axle flex AND divert the flex force to push down the axle for greater traction.
Because the track bar is not solidly mounted onto the axle, it gets subjected only to a pulling force; therefore it needs only be a simple rod.
The picture is of "my" kind of track bar.

Ingthorsson.


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[customhilux]

your spring pack is chock a block,

we remove alot of the leaves from the pack, thats y we u use trac bars,

hypolux had a single link bar and wrapped his springs.

[hypo]

single link trac bar works well if setup right.......

[ingthorsson]

Glad about the response mates.
I´m not trying to come off as a know it all; merely pointing out the theory of the matter.
There´s no doubt in my mind that a ladder bar kind of traction aid should work better than a single link. However,,, it weighs a whole lot more and is much more likely to cause binding, especially in a long-travel setup.
Those springs in the picture are russian GAZ springs; very soft. Even so, I removed some leafs after a few trial outings.

Ingthorsson.

[-Richo-]

Ive been thinking too about what would be the best setup for a traction bar. Find a pen or stick or somthing like a single link and grip either end and twist upward (opposite to the way the wheel would turn going forward) on one end to simulate the movement of the axle. It will hold, but it doesnt feel strong and there would be alot of stress on the joints. Now get a traingle shape of some kind, you could use a mobile phone for example. Grab one corner with one hand and with the other hand the 2 opposite corners to give you the triangle mounting pattern of a traction/ladder bar. Do the same movement as before, to me it feels a lot stronger. Household physics i know but it gives you a rough idea.

As far as binding is concerned, if you get heaps of travel you could possibly run heim joints on all corners? rather than a shackle type setup on the diff housing? The travel im now getting is only about 10 degrees off centre so i think just the one heim joint at the cross member will be enough.

Trac bar experts???

[ingthorsson]

A ladder bar is more effective as a traction aid than a track bar, but it is subjected to a bending force and therefore needs to be a lot stronger than the track bar. (I´ve seen ladder bars from a dragracer bent into unrecognizeable junk by the twisting force of the axle, and that was from less than 500 horses). That bending force is caused by the axle twist, pushing the front end of the bar under the frame and thereby pushing the rear end of it down onto the axle. A ladder bar of the right length will push nearly the whole vehicle weight onto the axle. Thats why they are used in drag racing. A drag racer also has, I believe, very stiff, short travel rear suspension, if any!
In a four wheeler there are other things to consider, namely long and soft suspension. The length of the suspension travel makes it necessary to think about binding and therefore placement of the front end of the traction aid. The softness of the springs may well cause them to flex enough, WITH traction aid, to eliminate binding to the point of being unnoticed.
What I call a true track bar is also somewhat handicapped by such soft springs because it needs the support of the spring to work; if the spring is soft enough to bend under the twisting force of the axle, the axle litterally rotating around the rear end of the track bar, it won´t do any good.
Anyways,,, I my not-so-expert opinion, I would recommend a ladder bar type of traction aid to go with very soft suspension. Or, preferably, go all the way to four link and coils; four link is definitely the best kind of suspension setup.
Track bars are fine as long as the springs are stiff enough to make them work. The 50K$ question is how stiff is enough???

Ingthorsson.

[-Richo-]

I thought traction bars and ladder bars were the same thing??



This is a ladder bar, so what is a traction bar then??

I wont have to worry about the force generated by 500 horses either, not in the 2.8 anyway

Going a 4 link coil setup to overcome wrap is a little overkill, lots of people run soft leaf packs and traction/ladder bars without any dramas. The springs im running are very soft and im not using a traction bar as yet, its ok but the wrap will take its toll over time so im going to put a traction bar in for sure.

[V6XtraHilux]

heres my 2 cents worth.....
i have a stock suspensioned IFS hilux with a V6 (124kW), with Air locker in the back axle.

On the road, no 4wd engaged, my rear springs wrap a little bit and then release, leading to rear wheel jump, only minor on the road, but still a pain in the arse.
Off road is a different story. Ive had friends look at my leaves as im trying to get up a rock shelf with air locker on (oh, im running 33s BFG MTs at 18-20psi, but only for the last 2 4wd trips, before that 30in BFG AT, but same probs) and they say that the leaves wrap heaps, and as the tyres (both types) grip and slip, grip and slip, as well as with the wrap, lead to a phenomenon I'm led to believe is called "Tramping", where the axle wrap produces a springing effect on the rear leaves, making the axle jump up and down, and the springing effect induces more springing into the leaf packs, that continues even after clutch in and foot off the gas. My ute's been known to bounce 6-10 inches while trying to get some grip. Not only is it dangerous, but it makes the back of the car jump sideways also, not good for tight rock trails!!

As the truck gets older (only 2 and bit years) the axle wrap has gotten worse, doing away with my idea of lift blocks, hence the 33s to get more clearance (and other reasons).

So, what Im saying, is from my experience, if you dont want to put a track bar (for insurance, daily driver, cost, legal engineering reasons) then IFS rear leaves are a good solution to more wheel travel, but know the limitatiosn and possible problems, and drive it to those limitations.

Im stuck with the leaves as they are, I cant afford a track bar, new shockies in / \ arrangement, nor would my insurance co. accept a track bar, and warranty issues also limit it, but i guess 33s limit or void my warranty if they knew about it!

And my tray usually carries 300-350kgs when off road!!
Just my experience, dont want to put anybody off, but IFS rears need more work than just replacing the leaves.
Cheers

[sierrajim]

Getting a trac bar engineered should not be a difficult thing to do, nor an expensive thing either.

The binding issues, well all i can say is that wheel travel is not everything. Wheel travel helps but if you've got heaps of travel and axle wrap problems taking its toll on springs, unis, diffs etc i think a trac bar and a little less travel is a good trade off.

Laying the shocks in /\ style won't solve axle wrap problems as you are not creating a solid link.

[ingthorsson]

It seems to me that we are getting a bit confused here on terminology and what is what! At least I am. So I went picture hunting to try to clear up the issue and proved yet again that the more you learn, the better you realize how little you know!
I found one link:
http://www.hotrodsandhemis.com/Traction.html
that explains in pictures better that I can do in words just why traction aids are needed. It also shows a good picture of what in my mind is the traditional Traction Bar and introduces, to me at least, yet another kind of traction aid; the Caltrac Traction Bars, a smart design but hardly applicable to an off road vehicle. Check it out.
The first picture shows the traditional Ladder Bar, here called a Lift Bar, and what is almost the same as the Caltracs, here called Traction Bar (wrong name I think):
Neither of those under-spring devices are feasible in a 4x4.
Then I found the one in the second picture:
Similar to what I call a Track Bar, but with added features that make it the smartest traction aid device for a 4x4 I´ve yet come across. It is the first traction aid I´ve ever seen that is specifically designed for offroaders.
Check out the homepage:
http://www.rockcrawler.com/features/new ... lsport.htm
I´m going for this kind in my planned project!
Hope this clears up the confusion.
Ingthorsson.

[shavedtoy]

so do you need to run a track bar with the ifs conversion or not and also should you then put your rear springs in the front,

[customhilux]

so do you need to run a track bar with the ifs conversion or not and also should you then put your rear springs in the front,

u remove leaves and u will,

i'm buildin one for mine now, using a 2 link setup,

if it turns out ok, i'll post up a drawing, and photo's, but the way i see my trac bar, is that it wont have any limiting factor on flex.

[Da Lux]

so has anyone fit 2" lifted ifs springs in yet, i dont really wanna block it

[-Richo-]

Gribble hasnt hes too lazy If youve got the springs just do it im sure it will work fine they will be the same length as standard height springs thats all that matters.

[Gribble]

Gribble hasnt hes too lazy If youve got the springs just do it im sure it will work fine they will be the same length as standard height springs thats all that matters.

F$#% you rooster-bag.

[308LUX]

probably a good idea to let those which are about to undertake this mod know that IFS springs will move your rear diff back roughly 4 1/2 " ... so either you will need to get your tail shaft lengthened or drill the spring perches to bring it back a little



Ohh and i found out the hard way.... yes you def need a track bar if you are planning on running the 3 leaf pack without the load springs... i wrapped mine like an 'S' on the maiden voyage

[hilux79]

What year hilux are your springs out of?

Didn't think it moved it back that far

[yamaha__308]

What year hilux are your springs out of?

Didn't think it moved it back that far

x2

Im using leafs from the coil front hilux and they should move the diff back only 3 inches - that is, the centre bolt is 3 inches further back from the front eye than stock rears. And im pretty sure with the IFS rears its less than 3 inches..

[308LUX]

What year hilux are your springs out of?

Didn't think it moved it back that far

x2

Im using leafs from the coil front hilux and they should move the diff back only 3 inches - that is, the centre bolt is 3 inches further back from the front eye than stock rears. And im pretty sure with the IFS rears its less than 3 inches..

Not exactly sure what model out of ... bought them off bundytunna here on OL he has about 20 pairs i think and im pretty sure he said they were out of 06 or 07 model ... i was looking underneath my mates 08 model hilux and they look pretty much identical

[Frankenyota]

The later coil spring front models have different rear springs.
IFS rears only move the diff back an inch or so.

Matt

[Lux_89]

basically.. if you use the correct length load bearing leaf in the ifs pack like i did, you do NOT need a track bar, even with my 3rz i did not find i was wrapping up too much. search my build thread for details.. i didnt move any mounts, combined with the 200mm eye eye shackle it had a 45o angle and i used a single 2 inch lifted leaf in the middle to retain the 2 inch i required/had before.. i measured my shocks to gain the best length. used standard lower mounts off a front diff on the back and used some custom uppers. Hope this helps..

Cheers, pm me for any other q's..