toyNG

I decided to try the ZUK mod using TJ coils after reading this on ZUK's site http://gearinstalls.com/coilphilbert.htm Scroll towards the bottom of the page to see the TJ info. I liked the idea because it did not require any changes to the truck whatsoever. The larger diameter of the coils allows you to have the coils wrap around the bump stop rather than placing them inside the bump stop. If I don't like it, I can simply remove the coils and the truck is back to where it was before the mod. Simplicity at its best.

I found come stock front coils off a TJ, borrowed a set of spring compressors from Autozone, and decided to install these. I measured the springs to be about 16" stock. I trimmed them down to ~12" using my angle grinder with a cut of wheel. Installing them was very straightforward. All I did was jack up the rear end, remove the tires, compress the coils, and just place them in there. With the suspension at full droop, the coils were slightly loose, just a bit wobbly. But I was definitely not able to remove or install them without the compressors.

Unfortunately, I didn't document this project very well. I didn't take a good set or before/after pics or before/after measurements. I really wish I would have, but I guess I did the install kind of on a whim without much planning. Here are some pics of them after the install.



driver side


passenger side



I would estimate that my before/after difference is about 3 inches. Keep in mind that my shocks were definitely worn, with some sag, but not to the extent that I've seen on many 4runners. My truck now has a bit of a rear rake, which I think looks ok.

As for the ride and comfort, on the road I don't notice much difference. The coils made some sounds right after I drove them, but haven't noticed any noise on the road since then. Off road, I actually think the ride is a bit stiffer now. I was somewhat disappointed by this. I couldn't find a definitive source regarding the spring rating for the stock TJ coils, but this site says they are 147 lb/in. http://www.jeepforum.com/forum/f9/fa...ements-638947/

My conclusions: This is a simple mod with great potential. For my truck, the coils are a bit stiff. But these might be perfect for the heavier 4runners. I really like how this mod does not require any modifications at all. Thus, it's easy to experiment with. I would like to find a coil with the same 4" diameter but with a spring rating of 100 lb/in. Any suggestions?

chubbydude

I would think front TJ coils would have a higher rating, but that is the benefit of buying an aftermarket coil which has an actual listed rating. Does not cutting a coil spring also increase the rating as well?

toyNG

I'm not sure what the difference in rating is between the front and rears. But I agree, if they are different, then I'd imagine the front's would be stiffer. I guess the rears might also be a better choice since they are shorter, although I'm not sure what their length is. If I can get my hands on a cheap/free set of rears, I'll install those and document the difference between the front and rears.

Regarding the effect that cutting the coils has on their rating....I don't know. Someone with a better understanding than me will have to chime in.

survivorman97

iTrader: (1)

So you said that you don't think that there is any way they could work there way out. What about if you were really flexing the suspension like the one tire is way way up and the other all the way down? Any chance they might come out? Wonder if a person could secure them in if they wanted too?

toyNG

With the suspension at full flex, it is probably possible for the springs to come out, although unlikely. If I decide to keep the springs in there, I will probably secure them by placing a bolt through the upper bump stop.

survivorman97

iTrader: (1)

That's what I was thinking. I really like the idea of this mod. Do you know if anyone has done it with a 3rd gen? Where did you get your TJ coil from? What year of TJ and these are from the front right? How much did you pay for them?

toyNG

Not sure if anyone has done it with a 3rd gen, but I don't see why it wouldn't work. I got the coils off a 05 TJ, from a friend. I'd imagine you could find a set for $30-40, but I'm not sure.

FastLane1000

Hey guys, I just did the mod too on my truck. I haven't driven it yet but it sits perfect. Here are my pics. We only cut about 1.5-2 inches off the coil at the top. I got the springs on ebay for $40 bucks or so. I used the rear TJ springs (stock height) where it looks like toyNG used the TJ front springs but cut them down a few inches.

toyNG

Let us know how they ride once you get a chance to test them out. What width are your tires? The rear TJ springs are quite a bit wider, so someone with wide tires might run into some problems. Looks like they won't be a problem for you.

FastLane1000

I drove it home from work and the ride is great. It is a bit stiffer but that was to be expected. I'm very happy with the results so far. That picture is a little misleading by the angle. There is a good inch of clearance between the springs and tires with 4" backspacing,15x7 wheels, and 265/75/15 tires. I will try to take a picture with a better angle tomorrow. They could be an issue with wider tires and possibly exhaust. I like that it was a 15 minute job with a lift and easily reversable.

FastLane1000

Here is another pictures that shows the tire clearance better.

poweredmotives

You think xj coils would be too stiff?

FastLane1000

Here is an update: The ride is really too stiff for me. It would be perfect i think if i regularly hauled a load or had a camper top or something. Mostly my bed is empty. I did however haul a heaping bed full of mulch from my parents house an hour and a half away and the truck did great and sat level fully loaded. I am pulling out the TJ rear coils this weekend and keeping them around for when i need them. pretty easy to install and remove.

pjb00stin

anyone have TJ springs on their 2nd gen 4runner?

4RunnerFreedom

this looks exactly like what i'm in need of. heading on a long road trip soon and need away to help with the sag and extra weight my rig will be carrying.

i've already had the springs re-arched and an extra leaf but it still has sag and will certainly be bottoming out once loaded.

anyone have a set of TJ springs they want to get rid off? or a suggestion where i can find a set of used ones? searched ebay with no success.

much obliged!

BLKNBLU

iTrader: (1)

I just searched "TJ coil spring" on e bay and several came up. Good luck.

4RunnerFreedom

thanks for the help blknblu. much appreciated.

4RunnerFreedom

found some springs locally for $40 for the pair. which end of the spring did you cut the excess from?

FastLane1000

I will be happy to sell mine, too stiff for me. I'll take $50 shipped. I have already cut off two inches so they will fit in the top bump stop. paypal lanegn@aol.com if you want them.

4RunnerFreedom

thanks fastlane1000 but i just got back from picking up a pair of fronts with only 4000 miles on them. going to cut those down 4" as the OP did and see what happens.

i went with the fronts because they are a narrower spring and have a higher capacity rating.

leaving on a 4-8 week roadtrip/relocation so i will have my rig pretty loaded down the entire time until i reach my final destination. and once i get there i can just pull them out and my ride goes back to normal. i have a slight sag now but i also have a sleeping/storage platform in the back built from 3/4 oak plywood and 2x6's so that alone adds some weight to the back end.