IFS and IRS on Hummer H3

[GreatDaneHummer]

Anyone know of someone making a long travel IFS and IRS on a Hummer H3? I spoke with a custom shop today that rebuilt the H1's suspension setup for competition racing. After looking at my H3 they felt pretty confidant it could be easily changed over to a race IFS and IRS setup using Dynatrac ProRock IFS/IRS axles. Thought it would be an interesting discussion on here.

 

[High Five H2]

sub'd. would be interesting to see.

 

[06 H3]

Lots of money.

 

[rsc]

Maybe throw in some rear star into the mix as well? Long travel would be the way to go, even given the cost involved.

 

[GreatDaneHummer]

I did read a thread about Bebe's long travel setup. I would love to hear from her on how its working now that its been a few years. I know that no one has done a IRS setup on an H3 yet. That would be new ground.

 

[GreatDaneHummer]

http://www.hummer4x4offroad.com/for...Long-Travel-H3-Build-Thread-A-Boy-Howdy-Story

 

[amrg]

Long travel upfront is probably the way to go, in the rear deavers may do (at least for a truck you want to drive on the road and cost wise)
Lots of people talk about LT on an H3 but apart from 2/3 ppl it never went mainstrean...

 

[SuperBuickGuy]

Where I play, IFS is really nice (fire roads, snow, etc), but I can't imagine how IRS would make it any better. Perhaps a long-arm kit in the back rather then the leaf springs (like trophy trucks), but the weight, complexity and (especially) the cost for minimal gains doesn't make much sense to me. Again, let me underline this for the type of offroad stuff, and what I use my truck for it would make no sense - that does not mean it wouldn't be perfect for you.

 

[GreatDaneHummer]

As far as trail running goes etc, I am a bit of a noob so as I find new things or concepts I am always up for a good discussion on pro / con's of a different way of doing things. From what I have seen, the IFS provides better ground clearance in the front vs. a solid axle. I was able to get through some nasty mud holes that my Jeep buddies got bottomed out on in the front. Of course bigger tires never hurts but I would like to get the max out of 37" tires.

 

[rsc]

We already have a good combination with the SA/IFS on our rigs, but the front really needs to be mid-travel and maybe long-travel for the larger obstacles. The limited travel up front makes most obstacles a 3WD affair as one wheel seems to always be off the ground. Sure, the rear could flex more, but why stop there? 4 wheel IFS/IRS would allow you to take on that rock garden obstacle course with more control and comfort in the extreme stuff. Or blast through the high speed desert stuff out west in comfort. Paying for that level of performance is expensive, but if you want a King of the Hammers H3 then that may be the way to go.

 

[SuperBuickGuy]

I'm only speaking to what/how I wheel... there are many ways where technique is the only difference and both types of vehicles are equally capable.

IFS has, at static ride height, better clearance - and it works wonderfully in snow because it is just like a sled - curved up nose with a wider body that creates floatation as it goes back. When you're in crusty snow, it'll kill a solid axle vehicle - however, if you're in soft snow the snow goes over and under the axle thus there is less drag (presuming the t-case and such are at the same height as the IFS) because you're only pushing the axle through the snow. Mud is similar. Rocks, not really my forte; but in my running of Rubicon, Fordyce and Johnson valley, I've found that traction rather then an inch extra clearance is the key to getting through.

With that said, I was with friends in Death Valley - where we were driving the hundred plus miles of dirt roads and I spent a great deal of time waiting for them because I could go a lot faster. Where IRS (rear) comes into play is on the track. When you hit the apex of a corner with your rear wheel - it effects both the inside and outside wheel since the force is transmitted across a rod (the axle). There is no analogous situation in offroad. The Ford Explorer has IRS, and that 3rd member works excellent in IRS cars - but it weighs a bunch. I put one on a car - I can normally slide 400-500 lbs. I couldn't move the IRS - so my guesstimate of that assembly is more then 1000 lbs. Compare that to the 300-500 for a Dana 60/Corp 14 bolt and you see the issue. You're carrying extra weight (that hurts you everywhere) for no real gain. On the track, it really helps you because the tire getting traction can hold it's line without being upset by what happened on the inside wheel. That said, mommy in her mall vehicle loves IRS because it rides better and isn't upset when she can't judge a turn and hits a curb.

ouch - that sounded mean.... no offense intended.

Then you come to the other issue.... that has to be stout kit to survive off-roading a 6000 lb vehicle with 37" tires.... in a buggy, it's easy because the force just isn't there to cause great torque.

Who knows what will happen, but in the next couple years I might start with a re-think of the suspension of my H3. Center-mounted-differential IFS, long-arm/travel rear suspension and perhaps diesel (though more likely a 6.2 LS motor) and 6 speed.... but I've many projects ahead of that and I may simply say no.... doing projects doesn't pay in my world.

 

[MTUH3]

I have looked at this in my own garage, and decided IRS would be too much work. The way the frame curves up in the rear and, and where you might need to set the pivots for the arms makes it a nightmare. IMO

As for front IFT LT. I am hoping next year I can look at this more closely. I have some thoughts, but this will not be cheap.

I have gotten to know the Brenthel's pretty well, and my thought is looking into one of their Silveraldo LT kits, or seeing if the are willing to build me a set of their discontinued LT for a Colorado or Jeep JK. They made a IFS LT for the JK years ago, but it discontinued.

Two major obstacles I see so far (excluding $$$), and this assumes I am buying a LT kit and modifying the truck to make it work.

1. All new upper and lower control arm mounts will need to be made and secured.... accurately. I think with support of a company like Baja Kits, they could help provide the X,Y,Z coordinates of each mount to get started.
2. To actually realize the full travel of the system, you need to raise the upper shock / coilover mount up. The H3 is compression limited (there is a lot more up travel available in a stock suspension that is limited by the shock length. Sam from Samco, who worked on projects with Rod Hall, developed a new upper shock mount. But that is going to require relocating a number of parts in the engine bay, and then fabricating or buying a new upper shock mount
3. New CV shafts in the front. They will be a custom length, so you will need to source and work it out.

All the other changes would be pretty mild, new tie rods, brake lines, ect.

Now if you went into cost....
Baja Kits LT - $5,000 (you will need to ask them to revise the knuckles to accept the H3 hub, or a compatible hub.
Front Coilovers - $2,500 (if you get something like King, Fox or Icon that can actually take advantage of the travel
Upper Shock / Coilmount - $1500
Axles - $2,000 (I am really not sure where those would actually price out, but guessing)

So you will be in it for close to $10k, and now you need to start developing the rear end to keep up....
$1,500 for Deaver springs
$2,200 for shocks, probably want to through another $500 in for a gas bump stop
And then you will need to either develop, a cantilever rear suspension, or cut a whole in your body and make custom shocks mounts (again to see full travel)

And now your front track width is going to be 4 or more inches wider than stock, so you might need custom fenders.

So.... If is possible. Hell yes. I don't think it is terribly scary if you can get a suspension company to help and walk you through the steps. It is going to cost a lot in parts alone. If you can do a lot of your own work, you can save a lot of money, but there are things that are "buy" items that will cost you. I don't think designing and fabricating you own control arms is time worth spent (unless you have CAD of the H3 frame and are very knowledgeable in suspension design).

You can decide how far to take it, and save money.. But my recommendation would be to call up SAMCO see if they can build you a new upper shock mount, and take advantage of what the vehicle already has.

I do plan on doing something like this to my truck, but that starts after I get another car, and my timeline will be in years... so don't plan on me leading the way anytime soon.