more lift to the superlift

[06JeepXKHEMI]

What issues did phunkeydude have? I really don't see an issue what so ever. Order the superlift, keep your HD coils, cut off a coil, install and be sad cause my jeep is still bigger sitting on brand new 34 inch MT/R's. Bwhahaha

Just let me get the 33's Ill chop up the XK for them, I do not care!!!

[Matt]

EDIT: Brain fart.... these part numbers are the REAR Springs

So just because i've been thinking about this and had a theory, I had to put some numbers to it and found something interesting.

OME992 = WK MD = XK LD = 13.6" free height, 7.2 coils, 240 lbf/in, 17mm wire
OME993 = WK HD = XK MD = 13.6" free height, 6.6 coils, 280 lbf/in, 18mm wire

OME992 with 1 coil removed:
11.7" free height, 6.2 coils, 280 lbf/in <---Note that this is like running the OME993 spring rate and 2" less pre-load in the assembly

OME993 with 1 coil removed:
11.5" free height, 5.6 coils, 330 lbf/in

Based on this, I think I'm going to try an OME992 with 1/2 coil removed:
12.7" free height, 6.7 coils, 260 lbf/in <---- This will give a spring rate in between the OME HD/MD springs, and an inch less preload in the assembly. So it should ride good, and if needed I can always cut another half coil off.

Note that free heights are estimations due to the fact that the top side of the coil closed/ground. But their relative differences to each other should be maintained for comparison purposes.

But still need to know whether kmax/phunk used the OME992 or OME993 spring. I have a feeling, based on the "stiff ride" comment that they cut down an OME993 spring and ended up with a 330 spring rate.

[07JeepXK]

My question is, how do you figure out the spring rate of a coil that has been cut down???

[Matt]

My question is, how do you figure out the spring rate of a coil that has been cut down???

Number of turns in the coil is one of the design parameters in a coil spring. If you know the spring rate and number of turns, you can calculate a given constant for that particular spring design which takes into account wire diameter, coil diameter and shear modulus. Once you know that constant (C) then spring rate k = C/N where N is the number of turns in the coil.

[07JeepXK]

And that my friend is why I joined the Army after high school!!!

[criket]

^LOL. Well said.

Just get some custom coilovers made for the front and rear and abuse the crap out of it, LOL.

[Matt]

^LOL. Well said.

Just get some custom coilovers made for the front and rear and abuse the crap out of it, LOL.

LOL

Coilovers are the long-term plan. Once i have the SL and can take some more accurate measurements i'll start spec'ing out a good set of coilovers; but in the mean time i'll have to come up with a configuration to run with that huge strut spacer, ugh.

[Matt]

Thanks for the info Dave!

And yeah, i was already planning on leaving that pre-load spacer out.

[valpacer]

I must admit i am not a fan of cut coils, but I also have access to getting custom coils made easily. The increase in spring rate can get harsh.

I know Omelet cut the top coil off his OME HD and seems happy.

The other thing to look at is the SL incorporates a preload spacer, which goes inside the strut assembly, and is usually good for around 1/2-3/4" (usually closer to 3/4) lift on the standard coil alone. I left these out so we could use the same length spring i previously had and not end up over 7" of lift. This keeps a large amount of flex and rebound abaility. Mine has settled at around 6.25" in the front, and the coils on a normal lift would be good for around 2.75" lift with the heavy bar, winch and batteries etc. If you could simulate the weight you will run on the front, and get a measurement for your current coils then add 3.5" you will be pretty close to your new lift height. Then go from there and try to work out a new spring, or trim down a lower rated coil.

From memory my front coils are 300 rated and 19mm, which gives you an idea on my Jeeps weight... And the struts are valved 25% over the OME.

[07JeepXK]

What struts are you using valpacer?