Bebe's H3 Spring Over Tech

[bebe]

Originally posted 2/8/09

We started the SOA project on my H3 today.

The goal is to net a 3 inch lift, add more flex, get rid of the obnoxious spring hangers, and increase ground clearance by flattening the underbelly.

We are not raising the front anymore than it already has been with an HD torsion bar lift. 2 1/2"s.

We will not be changing the IFS in the front. We will be returning to the stock rake (2 1/2" difference between front and rear fender heights)

I have had some problems with the rear leaf springs going flat, and when I added the H20 gear I went through 2 sets spring packs in about 40K miles. (I'm at 88K now and they are starting to get very saggy)

We had it weighed on the corners to get an idea what type of hybrid spring pack its gonna take to support the vehicle with the amount of trail time and commute time it gets.

It weighed in at 5950 lbs.

So we are going to use some Tahoe springs (4WD with a tow package) with the H3 main leaf and overload.

There is a fair amount of work left to do:

Remove Gas Tank Skid and build an outer skid
Cut off those ginormous spring hangers and weld on a much shorter hanger
Go back to the stock shackle (to net less lift than with the current extended shackle)
Rework the top of the axle spring plates ubolt flip yada yada yada

We are going to use the same Fox shocks (relocate the brackets)

So lots of ramping and measuring.

BTW the ramp part was embarrassing, but read it was about the same as a stock Jeep score...445.

 

[bebe]

some pics of today's progress...

 

[bebe]

The new springs + the stock vs extended shackles

 

[bebe]

We are planning on moving them to the axle, similar to the pic below and keeping them in the stock location on the upper mounts.

We are trying to minimize the fabrication and expense, and if that doesn't work we'll change them up to something that does.

We are hoping to keep it simple enough that most folks can do it on their own.

In my mind those hangers are the worst part of the Hummer H3 Design.

Here are some pics of a SOA that was done on a test vehicle we saw in Moab...

 

[bebe]

I already have the torsion bars cranked in the front and added HD 30% spring rate over stock SAW t-bars when I added the winch. Stock ride height sits at 37" from ground to the bottom of the fender flare. With the t-bar crank I gained 2.5" to 39.5".

In the rear I added an extended shackle, which at the time got me to 40" from ground to fender flare, but the springs are sagging again so now I am at 39". 05" lower than the front. The goal is to gain 2.5- 3" of lift in the rear. Stock is 39.5".

I would like to have the stock rake back. So total lift front and rear will net 3 inches +/-.

As far as ride, like I said in the above post, it rides great.

But I think the HD t-bars and the fox shocks helped a lot.

 

[bebe]

SO Monday night we removed the gas tank and plugged fuel lines...well speedy did that, I built the new welding cart

 

[bebe]

Removing the tank showed us how big those ginormous hangers really are....so it was time to cut them off...

 

[bebe]

Here is a pic of the new hanger, but we think it's too long, so I'm heading to Ruff Stuff tomorrow to see Gravel maker, and rummage through his hanger bins

 

[bebe]

Ok as requested moar pics

We are ok to go!

 

[bebe]

OK it's spec'd and right on. Tomorrow/Sunday, clean up, painting, finishing up.

We did have to remove one leaf to get to our target height of 42.5"

The camera crapped out and we ran out of batteries, so finished product pics will have to be done tomorrow.

Some pics from tonight:

 

[bebe]

more later

 

[06 H3]

I've been looking at your thread on pirate...for the rancho would I still modify the spring hangers? Use stock springs or a custom leaf pack like you used?

Sent from my DROIDX using Tapatalk

 

[bebe]

You can use a custom leaf pack, but you will likely need to go back to the stock leaf pack, and use the stock hangers.

 

[06 H3]

alright...then this project shouldnt be as bad. I wont need to drop the tank. Just re welding everything on top and setting the pinion angle. I could put in the longer brake lines too.
I do not fully understand what will cause axle wrap. are their some steps that are critical to preventing it? I would most definitely be getting flamed on pirate for that noob question :giggle:

 

[bebe]

Whether or not you will have axle wrap.

You will, to what degree is dependent on how well you set the pinion angle. Lifted, you may need a longer driveline (I did) to prevent breaking the rear section of the t-case where the driveline slips in.

 

[06 H3]

So I looked into this some more.

When welding on the mounts you want to set it at 0 degrees? then adjust the pinion angle via shim? In terms of axle wrap I found three ways to deal with this. 1 is a shim like these...
http://www.4wheelparts.com/Lift-Kit...Spring-Axle-Shim.aspx?t_c=1&t_s=101&t_pt=5502

or the stiffness of a spring. The softer the spring the more prone it is to axle wrap yet you dont want too stiff so you dont have a **** ride or limited travel. So my question is what is a good spring rate for an H3? Are the stock springs too soft, just right, or too stiff?

Option 3 is an anti axle wrap bar, which if set up right will work but I would want to keep every mount, including an axle wrap bar mount, above the axle.

I also would rather have the shock mounted like bebes, instead of the way the GM guys did it. I feel the lower I can put the shock mount without going under the axle the better so I can still have some decent up travel....this shouldnt require new upper shock mounts though right?

The last thought I have for now is how the leaf spring is arched. When I spoke to Jeff at Deaver a few months back he said a nicely arched spring will flex better and give a better distribution of down-up travel ratio. With the stock hangers and springs it seems like the springs will be a bit flatter then stock. Do you think it would be a good idea to chop the spring hanger off, use a shorter spring hanger and use a spring that has more arch to it?


Will the H3 need to be driven differently off road with the spring over and how will the COG change?

I guess that will do for now

I saw this and found this interesting with the shackle angle too. I guess rancho really wanted that smooth ride! lol...they went just a tad bit far though.

 

[bebe]

Awesome work Grass Hopper!

When reading online be sure to note that the discussion is very different with a Coil Sprung/Linked rear than it is with a Leaf Spring rear.

The H3 leaf pack was made for the H3, and it's a well designed pack to boot with the Hotchkiss design. So always starting with the OEM stuff an making improvements specifically in the performance direction you want to go.

The lift you are doing is minimal. So first you want to address pinion angle by rotating the pinion into it's correct position, and then welding on the spring perches, so that the spring will be sitting in the flattest position with the pinion angle corrected.

With Leaf Springs, the shims are used to fine tune the pinion angle.

The rear driveline will need to be lengthened once the Pinion angle is sorted.

 

[bebe]

COG will change because the vehicle is higher. (COG will be higher)

Rancho works hard at ride quality to keep customers from complaining and to reduce product returns.

 

[06 H3]

thanks! So using the OEM stuff will make life a lot easier and isnt necessarily a bad thing. I will need to replace some parts on the oem leaves first as they have seen better days. For the driveline, the person you used still has the specs needed so it would just need to be ordered or will I have to go out and take measurements?

 

[Sierra H3]

Looking at my truck, it seems that with the stock spring hangers, you would get a 6 plus inch lift. But, the new hangers appeared to be compensating. Is the net lift about 4 inches?

 

[06 H3]

looking at the H3 moab edition the stock leafs with the rancho made a nice level ride.

 

[Sierra H3]

I agree. I think they were on to something there. It should have inspired an SOA production variant. Now we have to do it on our own!

 

[06 H3]

I couldn't wait to see a gen 2 H3...I think they had some cool stuff going on.

Sent from my DROIDX using Tapatalk

 

[bebe]

thanks! So using the OEM stuff will make life a lot easier and isnt necessarily a bad thing. I will need to replace some parts on the oem leaves first as they have seen better days. For the driveline, the person you used still has the specs needed so it would just need to be ordered or will I have to go out and take measurements?

You will always have to measure, angles and distances. Jess makes a worksheet, all you do is print it, fill it out, and pdf or fax it back. A few days later your drive line arrives. Tis a thing of beauty.

 

[davidh3]

http://www.autoblog.com/2007/10/29/sema-2007-hummer-h3r/
it's SUA, and this H3 does not have rear sagging problem.... with Rancho 4" lift

HOW????