A long time ago in a galaxy far far away someone came up with the idea of using strips of bent metal as a spring. Not too long after that someone else put them under a 4wd and we ended up with leaf packs. Then this other guy decided if he shoved another leaf in there it would lift his 4wd. From then on that guy was famous.......well not really but something similar happened and we ended up with the Add-a-lead lift.
So how does it work? The answer is on Google somewhere but not in this thread.
Anyways, as far as I know there is only a couple places that sell an AAL specifically for Isuzu. At least they say it's specifically for Isuzu then charge out the butt for it. While it sucks that's the price to play in a vehicle the aftermarket doesn't support. Most of these are around half what the "Isuzu" specific AAL's cost.
Being the super nice guy I am I compiled a short list. Aftermarket companies are surprisingly tight lipped on their spring specs. Most of them are for 2.5" wide springs because SURPRISE!!!! most trucks and SUVs use 2.5" springs. Isuzu, and another much less famous brand that starts with a T, use 2.375" wide springs. There's a reason but again you'll need Google to find it. Just so everyone knows you CAN stick a 2.5" spring in a 2.375" pack. It takes 3-4 beers, lots of swearing and a hammer or big clamp. I may be wrong on the beer so buy at least a 24 pack.
Unlike my Coil Spring thread I'm can't tell you how much lift you'll get from a particular spring. The main reason is I don't know the weight on the rear axle of a 1g Trooper, Amigo or Rodeo. I'm going to make an educated guess on the Trooper. Just remember the key word in that sentence is GUESS. If you happen to know the weight on each axle of any of these vehicles post it or PM me.
Ok so I'm GUESSING a 1988-1991 Trooper has roughly 1510 lbs supported by the rear axle. Just so no one screams foul I used a highly scientific method and the v6 since the number was easy to find.
[Curb weight - engine weight] / # of axles - rear axle w/ brakes = weight on axle(RA)
[3370 - 350] / 2 - 200 = 1510
Keep in mind leaf packs get progressively STIFFER as they compress. I'm sure there's an equation to account for it but I DID NOT attempt to find it. This means all lift numbers should be on the low side.
The arch of the AAL will play a large role in how much lift you'll get. If two springs have an equal rate the one with more arch will always give more lift.
Another thing worth mentioning is that these springs can be trimmed down to increase their effective rate. That's why I included Pro-Comp P/N 13124-1. At 50.75" long it's more than 3" longer than a Troopers main spring. When cut down to 45" the rate jumps to 78.34 lbs/in. Take it down to 40" and the rate shoots to 111.54 lbs/in. So you're better off picking a longer spring with a lower rate then trimming it down to get the height you want.
When trimming a spring down there's a few things you can and CANNOT do. You ABSOLUTELY CANNOT use a torch to cut down a spring. Someone is going to contradict me on this and they are so full of s*** it's not even funny. Cutting a spring like that ruins the temper and it will fail, sometimes catastrophically.
The correct way to do it is with a saw of some sort. Once it's cut down you should use something to round the end off. A flapper wheel works best. This will help prevent it from eating into the springs it sits against. Before you blindly cut always run the numbers through a calculator. It'd be a shame to hack 7" off a brand new AAL only to realize the rate is way too high. This is the calculator I use and it has proven pretty accurate.
A good starting point for the rate is 25-30% of the Stock Trooper rate. Without the overload it is 140.77 lbs/in. We don't count the overload because it should only come into play under heavily loaded conditionsALWAYS USE A BRAND NEW CENTERING PIN
Remember if it's in big bold letters it's probably important.BDS
114202--arch 6.75"--length 42"--width 2.5"--thickness .26-- 51.68 lbs/in---1.4" liftRancho
Rs60622--arch 7"--length 45.75"--width 2.36"--thickness .26--rate 37.75 lbs/in---1.1" lift
Rs60613--arch 6.75"--length 44.76"--width 2.5--thickness .26--rate 42.7 lbs/in---1.25" lift
Rs60632--arch 6.25--length 42.75"--width 2.5--thickness .26--rate 49 lbs/in---1.3" lift
Rs60013--arch 8.65"--length 45.65--width 2.5"--thickness .32"--rate 75 lbs/in---1.8" liftPro-Comp
13160-1--arch 6.75--length 45--width 2.5-- thickness .25--rate 37 lbs/in---1" lift
13124-1--arch 7.62--length 50.25--width 2.5--thickness .32--rate 54 lbs/in
13120--arch ???--length 21"--width 2.375"--thickness .25"?--rate 349.17 lbs/in