|by: Chris Perosi
Lifting a Late-Model Isuzu
|Amigo with 3" Lift Scoring a 917 on The Ramp!|
There comes a time in every four wheeler's life when they decide enough is enough. They are tired of bottoming out, smacking the skid plates, and just in general, getting stuck. Immediately, thoughts turn to larger tires, however, shortly thereafter, even a novice will realize that the best way to maximize tire size is to first increase the space between the ground and the fenders, i.e. lift the truck. There are two major types of lifts, body lifts and suspension lifts. Both have their merits and their place in the four-wheeling world, however, generally a suspension lift will yield more benefits in addition to the extra space in the wheel wells -- more suspension travel, better or more refined ride quality, etc.
|One of the tell-tale signs that I needed a lift.|
Once the decision has been made to lift a vehicle, the first stop is usually to the local off-road shop to find out what kits are available. Generally a lift kit is a good idea, because many of them include all the parts you'll need, plus detailed instructions. This is great if you own a more common off-road vehicle, such as a Jeep -- you go to the local off-road shop, they tell you about the fifteen different lift kits you have to choose from, and you pick the one that's best suited to your four-wheeling needs. But what happens if you own something with much less of an aftermarket, like an Isuzu?
Fortunately, there are several aftermarket manufacturers supporting the Isuzu line, the most prominent in recent years being Calmini Manufacturing. Calmini has been in the business for years, and has always supported the Isuzu line, as well as other 4x4s that are relatively uncommon on the trail. They even helped drive the recent Suzuki rage that pushed the Samurai into its position as one of the easiest and cheapest 4x4s to build into a decent trail rig. ARB-USA is also supporting Isuzu owners with their Old Man Emu line of suspension lifts, as well as many other quality off-road and performance products for Isuzu enthusiasts. Buddy King from ARB has been an integral part of making more parts available for Isuzu owners through the publicity given to his Project 98 Amigo.
Unfortunately, as new vehicle models are released, these "niche market" manufacturers can't just go ahead and jump in with new products for them right away, since the volume of these vehicles in the the hands of the public just isn't enough to support full-blown product research and development. It would take years to recoup the investment, so many of the newer models get left unattended until the public has bought enough of them and enough of them are on the used vehicle market to make R&D cost efficient.
So what do you do if you find yourself needing to lift your truck, but unable to find a lift kit for it? Or what if you just want something a little different than the pre-packaged lifts that are available? The easiest option is to just go ahead and make a lift yourself. Custom suspension, that sounds pretty expensive, doesn't it? Well, it's really not, unless you're planning on a large amount of lift or some really unique features. For a mild to moderate lift, (2 - 4 inches) if you're willing to do a little legwork, you could easily find yourself with a custom suspension for around the same price as it would cost to purchase a full-blown kit (assuming one were available).
That's exactly the position I found myself in when I purchased my 1998 Amigo. I desperately wanted to lift it, but no lift kits were available. So I broke out the research, asked around, made some phone calls, and a few hundred dollars later, I had 3 inches of suspension lift under my truck, including new shocks. It was surprisingly easy, and rather inexpensive. After all, this isn't rocket science. The truly difficult parts were taken care of by a custom spring house, so it was really just a matter of deciding how much lift I wanted, and making it work. The techniques used here are universally applicable to any IFS front, coil-spring rear vehicle, however, further research would be required to apply these methods to vehicles other than Isuzus.
|Classic Isuzu Independent Front Suspension|
The front end on all Isuzu SUVs and 4x4s is a torsion-sprung, unequal-length a-arm Independent Front Suspension (IFS). This is a fairly complex suspension system in which longitudinally-mounted bars (the torsion bars) are twisted to provide the spring action. One end of the torsion bar is bolted to the lower a-arm, and the other is attached to a cross-member under the vehicle, underneath the driver and passenger doors. There's a certain amount of twist placed on the bar based on the weight of the vehicle, and when the tires compress up into the wheel wells, the torsion bars twist more. They "unravel" when the tires droop. Being "independent" front suspension, each side is free to move independently of the other, which generally keeps the ride-quality smooth, but is usually considered a liability in many off-road situations.
|Close-up of the adjustment bolt for the torsion bars.|
However, in the case of lifting a truck, this "liability" becomes a blessing. Part of the torsion bar system is a bolt and lever that attaches to the rear of the torsion bar to control the ride height. From the factory, this bolt is adjusted to a level somewhere in the middle of the full range of wheel travel, allowing for a relatively even amount of upward and downward travel. In order to raise the ride height, all you need to do is "crank" the torsion bars. This is done by tightening the adjustment bolt, which pulls the lever down, twisting the torsion bar toward the ground. The torsion bar already has a load on it, so instead of twisting more, it simply raises the load (the chassis).
That's all there is to it, free lift, for the front-end anyway. Of course, this is not without its downfalls. As a matter of fact, it's not even technically considered a suspension lift. Normally when you lift a suspension, you move the entire range of travel down away from the frame. In this case, you're only really adjusting the ride-height. Additionally, the torsion bars can only be comfortably cranked mildly before the process negatively affects ride-quality and pushes the wheel alignment outside of a correctable range. You also lose an equivalent amount of downtravel for every inch you gain in lift.
The actual amount that can be gained from this varies wildly from vehicle to vehicle, from 1/2 an inch or so on some short-travel IFS suspensions, all the way up to 4 inches or more on the newer Isuzus. The reason for this is that the 1998+ Rodeo and Amigo, late-model Troopers, and the VehiCROSS have longer a-arms than previous years, so they have more overall travel. More wheel travel means more downtravel can be taken away without affecting the ride-quality as much as with less wheel travel.
Because the a-arms are still limited to traveling between the upper and lower limts of travel (bumpstops or snubbers) replacement of shocks after doing a torsion bar lift is not necessary. On my Amigo, I chose to replace the front shocks anyway, since I wanted the adjustability offered by the Rancho RS9000s on both the front and the rear. For the 1998+ Amigo and Rodeo, the front shocks that fit correctly are Rancho part number RS9136.
|Comparison of the stock springs (left) with the Valley Spring Works springs (right). Note that new springs have more coils and are made of a thicker wire.|
Unfortunately, installing a mild lift in the rear of an IFS vehicle is nowhere near as easy as lifting the front. Generally speaking, IFS front ends get exponentially more complicated to lift as the lift height increases, since anything more than a mild lift would require a-arm replacement and/or drop-down brackets, as well as the inevitable torching of some of the stock components to make room for the new parts. However, the rear remains more constant in the level of difficulty, and basically involves either replacing the springs, or somehow adding to the area between the axle and the frame. On a coil-spring rear, this can easily be accomplished using coil-spring spacers, for an inch or two, however, I decided to use custom coil springs instead.
Any custom spring house can make up a set of custom coil springs for your vehicle, as long as they have the specifications for the stock springs, and a pretty good idea of what you want out of the new springs. In my case, I called Bill at Valley Spring Works in Dixon, CA, and told him that I wanted to lift my 1998 Amigo 3 inches. He already had the specifications for the stock springs, so all he had to do was increase the size of the spring so that it would be 3 inches larger when under a normal load. I also asked that he make them slightly stiffer, to help get rid of the "mushy" feeling the rear had from the factory.
|Here you can see the new springs and shocks installed on the truck.|
With the new springs in hand, I set about lifting the rear of the truck. With the frame resting on jack stands, I disconnected the rear shocks to make room to access the coil springs. I removed the stock coil springs using a set of MacPhereson Strut compressors. As easily as the old springs came out, the Valley springs went back in the same way. The shocks were then replaced using the Rancho RS9000s. For the 1998+ Amigo or Rodeo, the rear shocks for this application are Rancho part number RS9179.
Results and Conclusions
|Proving the capabilities of the lift on the Golden Crack in Moab, Utah.|
The results of the lift were amazing. In a few short hours in the driveway, I had lifted the truck 3 inches, which greatly improved angles of attack as well as overall articlation. The extra space in the wheel wells allowed for 265/75R16 tires (with some minor fender trimming). Additionally, the truck rides better on the highway and generally handles better. It's as if this is the way it was meant to be from the factory. Any late-model Isuzu owner with a coil-spring rear (1998+ Amigo, Rodeo, VehiCROSS, 1992+ Trooper) could easily replicate this lift with similar results, and I'd highly recommend doing that.
Since I first performed this lift in December of 1998, approximately 50 1998+ Amigo and Rodeo owners across the country have performed this lift, following my instructions. Check back soon for pictures of some of their lifted Amigos and Rodeos.
Several owners have modified the procedure for a little more or less lift, depending on what they wanted. It has been proven to work perfectly all the way up to 4 inches of lift. More than that could cause driveline vibrations due to the angle, and the wheel alignment may not be correctable to factory specifications.
Coming Soon: A step by step pictoral of the installation, as well as before and after statistical comparisons of general ride height and suspension travel.
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