Budget Boost Shocks

[MichiganDuck]

I've read on here before what shocks you can run with Budget Boosts, but can't find them.

So, using chevy drop shackles in the rear, what shocks can i use with no modifications? I've hear tj or jk shocks i think?

[Comanche County]

I used F350 shocks once, I forgot the year. I just combed through the big Napa shock book and found a longer set with the appropriate ends for an MJ.

 

Some here...although this is for an XJ, MJ rear shocks are longer.

http://www.lunghd.com/Tech_Articles/Suspension_Steering_Axles_and_Brakes/Budget_Lift.htm

[87Chief]

I use JK shocks. With a 2" lift. Some modifications will be needed but not too bad.

[MichiganDuck]

I use JK shocks. With a 2" lift. Some modifications will be needed but not too bad.

What kind of modifications?

[Pete M]

plenty of options out there. anything from stock length to shocks designed for a 3" lift will work. :thumbsup:

[MichiganDuck]

Any idea what shock lengths i should use then? Using a true 2 inch spacer in the front and chevy drop shackles from autozone in the rear. I'm sure somebody has done this homework!

[jeepsouth]

Any idea what shock lengths i should use then? Using a true 2 inch spacer in the front and chevy drop shackles from autozone in the rear. I'm sure somebody has done this homework!

I'm interested too.

[Pete M]

if you haven't changed the bumpstops, then your up travel hasn't changed. if you haven't changed your control arms, your downtravel hasn't changed. stock shocks work fine. shocks for a 3" lift will also work fine. no idea what any of their overall lengths are. :dunno:

[Eagle]

if you haven't changed the bumpstops, then your up travel hasn't changed. if you haven't changed your control arms, your downtravel hasn't changed. stock shocks work fine. shocks for a 3" lift will also work fine. no idea what any of their overall lengths are. :dunno:

 

Actually, if he hasn't changed the bump stops, shocks for a 3" lift may NOT work fine. They should be longer, and full suspension compression could bottom out the shocks before the bump stops make contact.

 

Goodbye shocks.

[Pete M]

true enough, they might. :thumbsup:

[MichiganDuck]

Do i need to change my bumpstops with a BB? Raise or lower?

[Pete M]

not usually. the big reason the add bumpstop extensions is if contact is occurring. i.e. if the shocks are bottoming out or if the tires are hitting the fenders.

[Eagle]

Do i need to change my bumpstops with a BB? Raise or lower?

 

It's not that simple.

 

Over-simplifying a bit (but not much), the shocks in a stock suspension are chosen so that at normal curb weight the shock piston is at mid-height in the shock body, and there's equal up-travel and down travel. The bump stops are set so the suspension hits the bump stop before the piston "bottoms out" in the shock body, and before the tire hits the bodywork. Everything works ... because everything was designed to work together. Looking up stock shocks on the Monroe web site, the total travel varies a bit from one shock to another but it's basically 7-1/2 inches.

 

http://www.monroe.co...talog/e-Catalog

 

http://www.monroe.co...LengthSheet.pdf

 

So you install a lift, and bigger tires. Let's pick a 4" lift and 31" tires for example. Stock tires are around 29" diameter, so a 31 is two inches bigger in diameter (duh!), or one inch higher above the axle.

 

The stock shock travel is 7-1/2". For simplicity, call it 8". Half of that is 4". If the shock piston is designed to ride at the point of mid-travel, if you lift the body 4" higher off the axle, the lift will actually pull the shock all the way up, and cause it to "top out" in the shock body. With a 2" budget boost, the piston will ride 2" higher in the shock body, but won't top out.

 

So for the 4" lift, we need a shock with more travel so the mid-travel point will be 4" higher. That's actually a shock 8 inches longer, for a total travel length of 16 inches. You're not going to find one, at least from Monroe. Their longest are in the 10-1/2" to 11" range (and those may not have the correct mounts on each end). But let's pretend you can find one that offer 12" of travel, to keep the math simple. The suspension is lifted 4 inches, the shock has 4" more travel, so the mid-travel point has been raised 2 inches. But with a 4" lift you're riding 2" higher than that, so you now don't have 6" of up-travel and 6" of down travel. You have 4" of up-travel and 8" of down travel.

 

Based on the original setup, you had 4" of down travel (actually, slightly less), and the bump stops were set to limit the travel to less than that so the shock wouldn't bottom out. If you don't change the bump stops, your down travel is the original 4" plus the 4" your lift added, so the body will now drop 8" before you hit the bump stops. With our theoretical shock, that's exactly at the point of bottoming out. Since there really isn't a shock offering 12" of travel, in a real world situation the shocks WILL bottom out before the bump stops make contact.

 

Back to the budget boost. Adjust the above numbers by a difference of 2" and see what you come up with. In a perfect world, you would use a shock 4 inches longer and extend the bump stops by a full 2 inches to protect the shocks. But you're really only likely to find a shock that's about 2" longer (around 10" or travel), raising the mid-travel point by one inch when the lift is about 2".

 

And none of this even deals with the other side of the problem, which is preventing bigger tires from hitting the bodywork.

[MichiganDuck]

Holy moley eagle.. That's a great explaination. I'll start looking!

Thanks guys!