Build Meet Ivy, 1976 FJ40 w/VW TDI, 2.8 CRD, OM606

[fjdiesel]

The way it is fitting up, it will be a bit of both... The lowers ended up at 12 degreees and the uppers look like they will be 45 degree area.

This is my first time doing 4 link, so I am all ears for imput!! I don't want to screw it up...

 

[mano002]

The way it is fitting up, it will be a bit of both... The lowers ended up at 12 degreees and the uppers look like they will be 45 degree area.

This is my first time doing 4 link, so I am all ears for imput!! I don't want to screw it up...

Everyone I know that has done links, has told me that linking is an iterative process. Use the 4link calculator, learn what all the numbers mean. Its a guess where your COG is, so take the numbers as such. Its all a compromise fitting it in all a stock frame, and then you will want to change how it feels to your driving style, where you wheel, etc. I am on iteration 2 and I will be doing a 3rd. I had roll-oversteer on iteration 1, made a drastic change to see if that got rid of it, and it did, but now I dont have enough anti-squat, so the sweet-spot is likely in the middle.

I also had a real tough time with coil-over placement: tire clearance at full-stuff, frame clearance at full-droop.

 

[fjdiesel]

Everyone I know that has done links, has told me that linking is an iterative process. Use the 4link calculator, learn what all the numbers mean. Its a guess where your COG is, so take the numbers as such. Its all a compromise fitting it in all a stock frame, and then you will want to change how it feels to your driving style, where you wheel, etc. I am on iteration 2 and I will be doing a 3rd. I had roll-oversteer on iteration 1, made a drastic change to see if that got rid of it, and it did, but now I dont have enough anti-squat, so the sweet-spot is likely in the middle.

I also had a real tough time with coil-over placement: tire clearance at full-stuff, frame clearance at full-droop.

Thank you. I am looking forward to see how it handles as well. I do expect that I will have a few more variations as well to find the sweet spot.

I did manage to get the lower bars made today and tacked together. Hopefully I will be able to get the upper mounts tacked in tomorrow afternoon... at least thats the plan for now.

 

[DangerNoodle]

Thank you. I am looking forward to see how it handles as well. I do expect that I will have a few more variations as well to find the sweet spot.

I did manage to get the lower bars made today and tacked together. Hopefully I will be able to get the upper mounts tacked in tomorrow afternoon... at least thats the plan for now.

Post up the geometry you are shooting for, we can probably help.

How come you aren't putting Johnny's on both ends?

 

[fjdiesel]

@DangerNoodle I will post up what I came up with. I had originally figured I wouldn't get that crazy that I would want JJ on both ends. And when I had talked to Barnes4wd, they said with the amount of road driving I do having the poly on one end would take out a bunch of road vibrations. Maybe I should have posted more of those questions here first...

I tried to get a slot for you to do it. lol. But the secretary said it wouldn't get done this winter. And I called in October. (I don't mean you specifically. Proffitts)

I called PRLC mainly because I wasn't sure that I understood 4 link well enough to tackle it. I have been playing around with measurements for a year or better before I started cutting the springs off. That being said, I changed the rear leafs at least 4 times and still wasn't happy with the performance. So, if I have to change a thing or 2 on the link setup to get it right that wouldn't be the end of the world.

The issue for me with the leafs was we drive the 40 to trails. So if we are going camping, its loaded on the way there. I couldn't get a happy medium between traveling and wheeling. I do have a m416 trailer that I think I will start using now, so I won't be so loaded on the 40.

 

[fjdiesel]

@DangerNoodle Here you are. This is where it is at right now. I am thinking I should raise the lower link at the axle .75" or 1"??? Let me know what you think.

 

[Lucille]

Id raise the lower axle mount to axle centerline or above. Your upper mount at the axle should be about 25% of your overall tire height. So if youre running a 36" tire, you need to have 9" of separation between the mounts. This is a general rule to be taken with a grain of salt. You will adjust your setup to fit around things you cant move, ie frame/tub/gas tank/etc. Ideally i like to get my lower links flat at ride height if at all possible. if your not building a subframe for the lowers, this could be difficult to achieve. Thats why rotating the lower axle mount an inch above axle center line would "cheat" this a little.

 

[DangerNoodle]

@DangerNoodle Here you are. This is where it is at right now. I am thinking I should raise the lower link at the axle .75" or 1"??? Let me know what you think.

View attachment 3248171

I would spread the uppers apart on the axle some. It will lower your roll axis and decrease body roll some.

The vertical seperation on the frame looks good, I'm shooting for about 5". Vert seperation on the axle side is usually recommended to be about 25% of your tire diameter, which it looks like you have that.

The older calculators are inaccurate for antisquat and antidive, so if you about half the values it is probably closer to what it really is. I can send you the most updated link calculator if you want.

 

[fjdiesel]

I would spread the uppers apart on the axle some. It will lower your roll axis and decrease body roll some.

The vertical seperation on the frame looks good, I'm shooting for about 5". Vert seperation on the axle side is usually recommended to be about 25% of your tire diameter, which it looks like you have that.

The older calculators are inaccurate for antisquat and antidive, so if you about half the values it is probably closer to what it really is. I can send you the most updated link calculator if you want.

Sounds good. Yes, please send me the new calculator. Thanks.

 

[fjdiesel]

Id raise the lower axle mount to axle centerline or above. Your upper mount at the axle should be about 25% of your overall tire height. So if youre running a 36" tire, you need to have 9" of separation between the mounts. This is a general rule to be taken with a grain of salt. You will adjust your setup to fit around things you cant move, ie frame/tub/gas tank/etc. Ideally i like to get my lower links flat at ride height if at all possible. if your not building a subframe for the lowers, this could be difficult to achieve. Thats why rotating the lower axle mount an inch above axle center line would "cheat" this a little.

I wondered if I needed to raise that mount a little...

 

[DangerNoodle]

I wondered if I needed to raise that mount a little...

I wouldn't worry about it too much. Your angle on the lowers isn't too bad, but it would be pretty easy to move them up a 1/2 inch as well. I would worry about the roll oversteer more though, Under zero is always preferred, but not too far under lol.

 

[mano002]

I would worry about the roll oversteer more though, Under zero is always preferred, but not too far under lol.

Based on my experience, I agree with this. I was cruising down the highway in a slight curve and a semi blew past me and the wind added to the steer and it made me turn into the truck that was passing me. Its a terribly unnerving feeling. I made a temp set of brackets that lowered my lower link frame side mounts and it went away. I need to cut them back off and raise the axle end to not have big brackets hanging down off the frame.

 

[fjdiesel]

I wouldn't worry about it too much. Your angle on the lowers isn't too bad, but it would be pretty easy to move them up a 1/2 inch as well. I would worry about the roll oversteer more though, Under zero is always preferred, but not too far under lol.

I hate to show my lack of knowledge here, but where is that on the new calculator?

 

[fjdiesel]

Thank you guys!! Everything is just tacked together right now. Easy to change right now!!!!

 

[DangerNoodle]

I hate to show my lack of knowledge here, but where is that on the new calculator?

3rd graph down on the sides. Roll Center calculations.

 

[fjdiesel]

Ok. I made some changes that will be very easy to make at this stage. How does this look? Is it too much negative on the roll center? And is a rear anti squat at 50 too low?
From my reading with the low anti squat it should take bumps really nice at the higher speeds. If I am reading that correctly.

I put these numbers into the new calculator at work today and they looked good. Not sure if I am missing something or downloaded it wrong at home, but the numbers are way different... So I just put them in the old calculator so I could post a pic.. Let me know how it looks. Thanks.

 

[DangerNoodle]

Ok. I made some changes that will be very easy to make at this stage. How does this look? Is it too much negative on the roll center? And is a rear anti squat at 50 too low?
From my reading with the low anti squat it should take bumps really nice at the higher speeds. If I am reading that correctly.

I put these numbers into the new calculator at work today and they looked good. Not sure if I am missing something or downloaded it wrong at home, but the numbers are way different... So I just put them in the old calculator so I could post a pic.. Let me know how it looks. Thanks.




View attachment 3248651

Old calculators are quite a bit off from what I have read, it doesn't take a lot of factors into account. The newer ones do, I would trust those numbers a lot more.

The roll center looks much better. Keep it around 0 - -3 degrees ish. I'd bet your antisquat is closer to 50%ish based on the new calculator, which is pretty good.

 

[sogncab]

I should probably run north to supervise one of these weekends.

Going to Apple Valley Wisconsin on Saturday for a snow run. I've got a spare 80 if you're interested. I think I'm going to trailer the 40

 

[fjdiesel]

Old calculators are quite a bit off from what I have read, it doesn't take a lot of factors into account. The newer ones do, I would trust those numbers a lot more.

The roll center looks much better. Keep it around 0 - -3 degrees ish. I'd bet your antisquat is closer to 50%ish based on the new calculator, which is pretty good.

Roger that. When I get to work I will put the numbers in the new version and post a pic. Thanks DJ!

 

[fjdiesel]

I should probably run north to supervise one of these weekends.

Going to Apple Valley Wisconsin on Saturday for a snow run. I've got a spare 80 if you're interested. I think I'm going to trailer the 40

Nice! Sounds like fun, I have wanted to run the trails over there. We will chat on the 80. Thanks.

I was gonna ask you what air filter they put on your build. Do you have a part number or dimensions?