My "Hero" Blog

[GordoSmasho]

Looks super sick kev. Nice work.

How did you end up running exhaust around that crossmember. Wonder if you have any finish shots of the crossmember.

[98jeepster]

Been following your whole build jeep looks amazing can't wait too see what's next! Was wondering why you went with 3 link and the upper on passenger side? Saw some other comments with people having theirs on pass side too. Any special reason? I'm just curious cause I ran mine on drivers side

[Mike1331]

It's for exhaust mani clearance.

[Jeep450r]

Thanks guys! I'm actually still on 33s. I'm contemplating making the jump to 35s but have a few clearance issues I need to work out. Because I'm running wheel spacers to clear the offset tie rod ends, the wheel moves forward and backward in the wheel well a lot when I turn. So when the wheel is stuffed and turned, I already contact the fender and my rocker replacement. I'd have to push the front end even further forward, do some complicated metal repairs to the sliders, or jump to 16s or 17s to clear the TREs and being the scrub radius back in in order to get the 35s to clear.






Gordo, here's an exhaust shot for you. It's a tight squeeze and I'm not happy with it. There's a flex pipe in front of the crossmember that you can't see, and the exhaust is hard mounted to the crossmember (temp mount shown). I'll hopefully be making some tweaks to the exhaust this week or next and I can take more pictures for you then.




Here's a few more shots from Saturday.









New front clip coming this week.

[Jeep450r]

Originally Posted by 98jeepster

Been following your whole build jeep looks amazing can't wait too see what's next! Was wondering why you went with 3 link and the upper on passenger side? Saw some other comments with people having theirs on pass side too. Any special reason? I'm just curious cause I ran mine on drivers side

It's cool to see that more than a few locals are watching this build. Thanks for the compliment!

I put the upper on the passenger side for a handful of reasons. It allowed me to place the frame side upper link wherever I want laterally without having to worry about driveshaft interference and I could have pushed the mount all the way against the frame rail without having to worry about the gas lines. It also gave me more freedom for optimal axle side upper mount placement due to the amount of axle tube for prime placement. Furthermore, it allowed me to cut a gaping hole in the passenger side floorboard rather than the drivers side floorboard for the upper link, so I don't have to deal with any sheet metal work around the pedals or at my feet. And lastly, to avoid pumpkin/truss/drivers side upper link mount interference with the track bar and panhard bar/pitman arm at full bump with the axle pushed forward. You can see in the below picture how close the pitman would be to the link mount if I trussed it and had an upper mount up there.

[GordoSmasho]

Wow is that tight. Do you have a cat in there or just pipe? That flat belly is sick.

[Mike1331]

Wow those 33's look big.

[blondejoncherokee]

is the upper link flat at ride height, or angled down towards the frame side? can you post pics of the frame side Upper link mount?

I like the 3 link man. I would recommend adding some gusseting to the UCA and trackbar mounts if possible though, even just some simple triangles to the UCA mount axle side would probably be enough?

[Goose_XJ88]

Youre finally going to get the grill insert from me? lol

[Jeep450r]

Originally Posted by GordoSmasho

Wow is that tight. Do you have a cat in there or just pipe? That flat belly is sick.

No cat, just pipe. Yep, super tight. I don't like it. Because of my lower link placement, I couldn't cut my cross member for clearance. I have a bunch of sheet metal work to do anyway, so I am planning on cutting the floorboard out where it is in the way of the exhaust and will rebuild part of the trans tunnel to allow for more room down there. Lots of work, I don't see any other way as of now.

Originally Posted by blondejoncherokee

is the upper link flat at ride height, or angled down towards the frame side? can you post pics of the frame side Upper link mount?

I like the 3 link man. I would recommend adding some gusseting to the UCA and trackbar mounts if possible though, even just some simple triangles to the UCA mount axle side would probably be enough?

Thanks Jon! Its pretty much level, but my angle finder is showing a 1* slope downwards toward the frame.

I went out to snap you a picture of the upper mount and ran out of memory on my phone after the first picture. Heres what I got.



It has bracing on the back side too that is not shown.

[moparmansfield]

You do some nice work man. I think I missed what you're doing in school.. Mechanical engineering?

[Jeep450r]

Originally Posted by moparmansfield

You do some nice work man. I think I missed what you're doing in school.. Mechanical engineering?

Thanks a lot, I appreciate it! Yep, I'm studying Mechanical Engineering.

[twinhauler]

The split-pivot design has always intrigued me, never ridin it! Your computer rendering looks sweet! Are you gonna be building a ridable bike for your project. Oh and the XJ 3 link looks like it worked good, and sounds like it drives great!

[Jeep450r]

Originally Posted by twinhauler

The split-pivot design has always intrigued me, never ridin it! Your computer rendering looks sweet! Are you gonna be building a ridable bike for your project. Oh and the XJ 3 link looks like it worked good, and sounds like it drives great!

Thanks John. I cant take full credit for the rendering, it has been a group effort. We just ran one of the pieces on the CNC mill today. We used high-density foam and it will be the mold for our carbon fiber layup.



The ultimate plan is to have a rideable bike in the end, but time will tell.



I weighed the jeep this past week. 3990# empty with a full tank of gas. I expect 4500-4700ish loaded down? With 2 people in it, we were at 2320# in the front, and 1980# in the rear. Once I'm loaded down, it will make for a pretty equal front/rear split.



I've been doing a lot of research on the 3 link lately. I downloaded Triaged's link calculator and finally ran the numbers.



Center of gravity approximated as the top of the bell housing - I hope to calculate my true center of gravity soon)

The reason I haven't run these numbers before is because there were some basic parameters that I was building the 3 link to, and ultimately it boiled down to putting things where they fit while best following the basic 3 link guidelines. I built the track bar as long as I could, I got 8.25" vertical separation at the axle, pushed the axle side lowers out as far as I could horizontally, brought the frame side lowers in horizontally to where it would clear the frame rails at bump, tucked the lowers up as far as I could, and put the frame side upper as far up as I could without it intruding into the passenger side floor space. The above numbers are what I ended up with.

The roll axis angle makes me very happy (I am very close to no over or under steer), the roll center height seems fair to me (still researching optimal height), but the anti-dive (shown as anti-squat) is not cutting it.

For those of you that are not familiar with the details of suspension design, anti-dive directly relates to the amount of brake dive you experience under braking. The value defines the dispersion of the rotational forces of the wheel/rotor into the suspension links and the springs/shocks. At 100% anti dive, the suspension links are taking 100% of the braking forces, while the springs take 0%. As a result, the front end does not 'dive' at all, because the forces being placed into the control arms is combating the forces that would normally cause the suspension to compress. At over 100% anti-dive, the rotational forces from the brakes are translated through the suspension links in such a way that the suspension links push the body up and away from the wheels/axle. This causes the front end to actually lift when you hit the brakes. Anti-dive values less than 100% allow the springs/shocks to take some of the load. I.E. at 70% anti-dive, the control arms take 70% of the load, while the springs and shocks take 30%.

Disclaimer - that is my understanding. Please correct me if I'm wrong.

Excessive anti-dive can often lead to the tires being more prone to skipping/skidding when you are on the brakes. This can be bad on the road, and also when trying to feather the brakes to let you slowly drop down a ledge or rock.

Anywho, I'm at 102.69%. I drove around town with my roommate and had him watch the upper control arm through the hole in the floor as I slammed on the brakes and he confirmed that the control arm did not move up or down at all, with a very small chance that it actually moved down minimally (front end lifting) as I slammed on the brakes.

The options I have to lower the % anti-dive is to lower the frame side lower mounts, raise the lower axle side mounts, lower the axle side upper link location on its mount, or raise the frame side upper mount. Changing either of the lower mounts would be too much work, and I am very happy with the amount of vertical separation I have at the axle, so I will be raising the frame side upper mount 4", with adjustability every inch. This allows me to adjust the anti-dive from 102.69% down to 90.04%, 77.32%, 64.52%, and 51.63%, respectively from the bottom hole to the top hole.

From what I have gathered, 60-70% anti-dive is a fair number for rock crawling. I have nothing to back it up as that is based off of personal opinions, but I'm building adjustability into it this go-round so I can do my own testing to find what I like best.

Anyway, is what I'm doing overkill and most likely unneccesary? Most likely. But I am enjoying the hell out of it, and I didn't spend all this time building it just to settle.

I had to pull the crossmember out anyways due to some clearance issues (tcase to crossmember) and because the seal between the transmission and transfer case is leaking (thanks to the clocking ring). While its out, I'll be rebuilding that upper mount.




I hope you guys find this tech interesting and useful. Also, please correct me if I am misunderstanding something or spreading bad info. And if you have already been through all of this before, let me know what worked for you.

[87matchief]

Well shit I just read through a 101 pages to catch up here and dam man sweet build, very clean work,keep it up, I would have kicked my jeep to the curb after the 3rd bell housing crack haha but im also lazy and hardly work on my junk. but after reading this makes me want to get back at it. looking forward to see what else you come up with