DD Hemi Suspension Conundrum...Cherry Bomb

[JeepLab]

So I fielded an email today, and Im going to answer it with this thread.

If you are just tuning in to JL, Cherry Bomb is a 392 HEMI JK. Owned by a regular guy. Regular, if you think an attorney tearing engines apart in his garage is regular. This guy rolls up his sleeves and gets in there. A "bends his own stainless pipe" sort of guy....

Anyhow, Cherry Bomb, started out as a Magnuson supercharged JK, but the tune never got where the owner wanted it, So not only did he rip the SC off, he ripped the engine out. Awsome right? Mostly. The power is unending. no question about it. The suspension needs a fresh look now that there is an extra 400lbs sitting over the front axle in addition to some other heavy front end parts, including AEV front bumper and winch. (i think, gary feel free to correct me if im not setting the scene right )

This truck although highy modded, is a daily driver. Now. The owner needs reliablilty and driveablilty.

I said coil it over. The shop he uses told him that coil overs need rebuilds from time to time and that for his use, a separate spring and shock combo would be better suited.

The email asked me to weigh in on the next step in this suspension evolution, and also other changes to help handling, wich is kinda my forte. I dont like clumsy jeeps. Jeeps can be razor sharp instruments built correctly.

[JeepLab]

So thats the scene, Here's my answer to the question.

The shop he used also saw Black Betty. She was on a lift there, and her suspension was something very unusual to the mechanics there. A few were underneath looking at it like it was made by aliens. I was in the shop with them. BB wears a 2.5" Rock Krawler 3 Link long arm coil over stage 2 suspension. Pretty much top of the suspension food chain. There is only one step further to go, and that would be a coilover rear.

Shop says - coilovers are less reliable because they need to be rebuilt from time to time. And the amount he drives would require maintenence.

I say - If your coilovers need to be rebuilt, the other option of separate springs and shocks probably need to be replaced, trying to hold up that monster.
I also say - This is a guy who didnt like a 6k power mod, so he tore the trucks heart out. Rebuilding coilovers IF he got them to that point would not be as bad as him putting in a spring and shot combo, deciding he still isnt satisfied and THEN doing coilovers.

We parked the two trucks side by side for a little while and you could see BB had a considerable amount more spring, and to stabilize that spring is a remote reservoir 2.625 remote reservoir shock.

Also, the coilover is adjustable. So where you set the spring in BB with 500 lbs less nose weight, would be different from where you set Cherry Bomb.

I think any standard spring will be overmatched by the weight in that nose, a standard shock will struggle to stabilize that struggling spring.

[JeepLab]

not finished yet....

I've blown coilovers out before. I did it at rausch creek once, we hit a fitting on something, and spewed out the oil. Even with the shock dead, the springs in this case would be such an upgrade to getting this beast under control.

So from my perspective, Coilovers are the choice.

1. The question becomes which coilovers do you get? Here's what I'd do next, research how coilover shock companies deal with returns for problems. If you blow one, do they send you a new one?, or do you have to send yours in and wait? thats the draw back. I dont know anyones policys on the matter. (matter of a blown shock)

2. Adjustability - RK's coilover can be tuned to your type of driving, maybe others can custom tune also, So Gary says he has a hemi, and they valve the shock up to deal with that weight, or give heavier duty springs, BEFORE we get to the point of Gary being able to adjust further in his garage with the lock rings and spanner wrenches.

3. Broaden the view. - You knew this was coming counselor, The final step is to strip weight. But I wouldnt do it until the coilovers are in. You may not feel like you need to change the weight of the truck if the suspension wasnt suffering underneath it. If you try to go standard spring and shock, then the steel everywhere else has to go.

4. Rebuilds - I sincerely do not think you will care about this. I would check that a shop near your home can do it IF you feel its neccessary. I sincerely do not think your truck will drive badly. What will happen will be that your truck drives incredible when you take it home, and you feel the coilovers moving. You will enjoy it and hit train tracks harder than you should at first. then 2 years later, you may hit the same train tracks and think to yourself, that wasnt as much fun as before, and you may treat yourself to a rebuild.

It will not be, "oh this truck drives awful, i need a rebuild". not at all. You may never feel the need for it.

I think id go as far as to say id take a blown coilover over a standard shock, spring combo in this case. So to me this decision is not really a close one.

[gbaumann]

You got it spot on. The scene is set perfectly. I too believe that the jeep can handle awesomely with the right set up. The techs at the shop felt that because I put over 20k miles per year on my truck I should stick with separate springs and shocks. Coil overs, they think, with heim joints and hand built components are awesome. But they need periodic re-building which, unless you have another set to swap, causes down time. And I'm told it's expensive. Right now they say it's running 6 to 8 weeks to rebuild the coil overs some of them use on their own trucks.

So far I've put in a JKS trackbar, a synergy tie rod and I'm awaiting delivery of a synergy drag link. The synergy components have 1-ton ends which should stand up better over time given the weight of the motor. Oh, and I stepped up one size in OME steering stabilizer.

So, I'm up for suggestions. King shocks? Fox shocks? Another shock? Anybody make custom coils springs? Remote reservoir? I was on the list to receive an early set of OME BP-51 adjustable bypass shocks from ARB. But after waiting we found out that they won't be in the US for almost another year.

[JeepLab]

You got it spot on. The scene is set perfectly. I too believe that the jeep can handle awesomely with the right set up. The techs at the shop felt that because I put over 20k miles per year on my truck I should stick with separate springs and shocks. Coil overs, they think, with heim joints and hand built components are awesome. But they need periodic re-building which, unless you have another set to swap, causes down time. And I'm told it's expensive. Right now they say it's running 6 to 8 weeks to rebuild the coil overs some of them use on their own trucks.

So far I've put in a JKS trackbar, a synergy tie rod and I'm awaiting delivery of a synergy drag link. The synergy components have 1-ton ends which should stand up better over time given the weight of the motor. Oh, and I stepped up one size in OME steering stabilizer.

So, I'm up for suggestions. King shocks? Fox shocks? Another shock? Anybody make custom coils springs? Remote reservoir? I was on the list to receive an early set of OME BP-51 adjustable bypass shocks from ARB. But after waiting we found out that they won't be in the US for almost another year.

6 weeks for a rebuild means you are dealing with someone who you shouldnt. That is rediculous. Its a few hours to do. I'd call fox and king an RK and others, and see what they say. Also, a guy like you could probably do a rebuild himself. Its not rocket science.

[gbaumann]

If I go with coilovers will I need to modify the shock towers? I do like the fact that you can adjust them with the lock rings. Let's spec and price a set. So I have to rebuild them now and again. Most of my driving is highway so I suspect I will have quite a long interval despite driving a lot of miles.

And yes, reluctantly I accept the fact that I need to lose weight. The stuff on the jeep looks cool but the truth is I can't see any of it while I'm driving (accept the hood which looks really cool too). No need to carry the fuel cell on back or big bumpers. The suspension deserves a rest from carrying all of that around. And, I will always accept the feel of more power from having less weight as a nice side effect.

[bo9roadking]

I'm running King coilovers and King triple bypass shocks on my JKU. They are EVO spec'd and I've put about 40K miles on them without a rebuild. EVO1 has the same setup, but runs the 6.4 Hemi. You could call offroadevolution (EVO) to see what spring rates they use on their EVO1 JKU. Their setup should work with your Hemi and the added weight. If you are worried about downtime if/when the time comes to rebuild the coilovers, EVO has King bolt-on coilovers that I'm sure they can configure with the correct spring rates for your Hemi. Since the bolt-on coilovers use the existing factory brackets, you could always put your current springs and shocks back on your JKU when you send the coilovers in for a rebuild.

[ljvsnyder]

I want to go to coil overs in the future. I would stick with RK, i am sure they could help come up with a spring package that would be more complementary to your setup than most other companies. I believe and Ross correct if I am wrong, hasn't RK done some hemi swap builds before, maybe not for a DD.

I assume cherry bomb is a rubicon, is the Dana 44 heavy enough to handle the weight of the engine?

[gbaumann]

Cherry Bomb is a Sahara. I knew going in I'd be changing axles at some point and I wanted ARB air lockers and manual sway bar disconnects. Front axle is a D30 which has same tube and C size as the D44 but with much smaller ring and pinion. Hemi or not the D30/44 will bend at some point and be replaced by ProRock D44/60 or an equivalent.

[Pznivy]

I don't like a bolt in shock tower personally, I feel like its a half measure, Your putting those shocks in to deal with higher tolerances. You want them welded. They should also be at least 3/16s steel if not thicker. Thats the kind of bond we are talking about. Not a bolt. Don't tell me its a big bolt. I don't care. LOL.