Decided it's time to Go Fast - now what?

Get ready to read a book.

I've always loved going fast - owned a few LS1/LS2 cars before getting into off-roading. My first time out to the Badlands was in a stock ZJ, and I had a blast tearing up and down the dunes. Fast forward a year, I've got a junky-looking (but getting better) XJ, which the PO threw a 4.5" Rusty's lift, Rough Country drop bracket, and 33" tires on. This is not a DD, at all. I don't mind cutting stuff, ripping stuff out (mostly done), whatever it takes. I have done some "spirited" off-road driving in my XJ, but it leaves much to be desired. After watching the TREC race at the Badlands last weekend, I am sure this is the direction I want my Jeep to go in.

I've been reading tons about JeepSpeed, Prerunner-type stuff, and just Going Fast in general. Both in this forum and others. I have yet to find a "Going fast for noobs" thread or post that really breaks down what it takes to make an XJ great for this, but I'm starting to get a feel for the things that are typically done. I want to list my observations (which more or less correspond with my plans for the Jeep) and see if I'm "getting" this. Where I live (Midwest) I will never actually see JeepSpeed, so following their requirements isn't necessary for me, unless everyone agrees it's a good idea.

Shocks. They are playing as crucial of a role as the springs. Remote reservoirs = necessary. 2" body diameter seems to be minimum. Length to be determined by travel. In the rear, punching holes in the floor and moving shock mounts will likely be required? In the front, a kit from someone like T&J to eliminate the shock stem mount would be good?

Travel. Is front travel more crucial than rear travel? Long arms definitely help keep the arms parallel, and seem like a good idea if affordable. What is ideal lift height? I'm comfortable at 4.5" for crawling, but it seems like 5.5" might be a sweet spot?

Quality springs. Progressive rate coils - pretty sure I've seen these, where the coil distance varies throughout the coil? Deaver "springs" to mind. Also other quality coils for instance from RE. Not sure on other vendors. For leafs, it seems like Deavers or Nationals with a high leaf count are the only real way to go.

Bump stops / limiting straps. I need to do this anyway. It seems like a cheap route is poly bump stops. Air/hydro seem very pricey, but since this is new to me I'm not sure how important they are. The ACOS Pros do look pretty nice, I may hold out for a used set.

Weight distribution. I'm clueless on this, but it seems like getting close to 50/50 would be good. I have gotten a bit of air in my XJ, and it's pretty obvious that it's front heavy when I'm coming down and can't see the horizon. Not sure how to accomplish this. No ridiculous front bumper or winch. Can't remove a lot of weight in the front. Spare tire in the back, of course, with other equipment?

Trussing. It looks like go-fast stuff means trusses under the axle, which will hurt for any crawling I may do, but is well worth it to keep things together. I would plan on keep the D30 for as long as possible, and I have a locked D44 in the works for the rear.

Fenders. What is the deal with these, is it a JeepSpeed requirement to have your tires completely covered? I'm not sure I see the point, but I'm sure someone will enlighten me

Cliffs: What do I need to get started? Awesome shocks (with solid mounts, and in the cab if necessary) and quality springs are pretty much the first thing. Long arms, trusses, and better weight distribution are secondary things to look into.

Does that make sense to anyone? Do I have a handle on what I'm going to have to do to make this happen? Right now I'm just trying to plan out my first steps. Obviously there are many other specifics like shock sizing valving, spring rates, etc. that I need to become VERY familiar with.

Getting started isnt cheap but after you get past the suspension its relatively budget friendly for a pre runner, but by no means a racer. Everything you listed is pretty well correct. On the shocks, the bigger the diameter, the better. Reserviors arnt a "must" but definatly helps. Shocks Body Diameter and and reservoirs or no all depends on what you plan to do. If you are just wanting to go balls out for about 15 minutes then a good 2.0 non resi would suit you. For a good 30 minute run go at least 2.0 with resi but Id suggest a 2.5 resi. Anything over straight out non stop for 40-45 minutes youll pretty well have to go with a 3" body shock. Springs, ya want deaver or national preferably but people have luck with full traction and rubicon express, and Im running Rock Crawler which is just shy of the deaver rate but non progressive and the rear leaves is only a 5 pack which I wouldnt suggest. Bump stops and limit straps front, limit straps arnt really required in rear unless you link it or you want them as a safety measure. Axles the keywords are truss and gussets. A must. Fenders are up to you, there are several companys now making them, and alot of them are the exact same. Long arm improves front travel but if on a budget a short arm drop bracket kit is popular. Travel wise, go the most you can with what you got. Dont really matter if one end has more travel but the front you want uptravel and a decent amount of it like 4-5" unless you have air bumps. Rear I find is better to have more down travel than up

Anybody else gonna pitch in their .02 to help a newbie get going?

hmm sounds like fun let me know if you need any help.. including parts. I work at a local "real" parts house!

If ya need something to get ideas from ya can meet me at the Jamboree September 18, 19, 20 or the short course race in Casey, Ill October 10th and 11th.

Shocks. They are playing as crucial of a role as the springs. Remote reservoirs = necessary. 2" body diameter seems to be minimum. Length to be determined by travel. In the rear, punching holes in the floor and moving shock mounts will likely be required? In the front, a kit from someone like T&J to eliminate the shock stem mount would be good?

My take on the spring rates, is they are there to hold the rig up at the ride height you want, without unseating at droop, and without binding at bump. Keep in mind this is a very general simplistic way to look at this...

Shocks are there to control the movement. Basically the bigger the shock body, the more oil it holds, the longer it will resist over heating. With adequate air flow over the shocks they will stay much cooler. They do have a good operating temp range where they work most efficiently, so they do need a little warm up time.

The rear shocks are a much tougher job to keep cool with the limited air flow in the back of the ole station wagons. On our jeepspeed, we run some air ducts to the rear shocks to keep them in check, but they still get plenty hot. We rebuild our shocks after every race, and the oil in the front shocks is always relatively clean, but the oil in the rear shocks is almost always black.

Travel. Is front travel more crucial than rear travel? Long arms definitely help keep the arms parallel, and seem like a good idea if affordable. What is ideal lift height? I'm comfortable at 4.5" for crawling, but it seems like 5.5" might be a sweet spot?

In jeepspeed, we're limited to 10" of travel in the front. I think my opinion of the suspension dynamics may differ from a lot of people's, but it works well in our application. Ours is set up with about 4.5" of bump travel at ride height. It helps to keep the nose up on top of the whoops at speed.

Long arms work well, but they're not necessarily any better than the short arms, as long as you have the drop brackets. A lot of the fastest jeepspeeders are running short arms.

The lift height will be determined by where you set up your travel numbers...refer to my general spring rate theory.

Bump stops / limiting straps. I need to do this anyway. It seems like a cheap route is poly bump stops. Air/hydro seem very pricey, but since this is new to me I'm not sure how important they are. The ACOS Pros do look pretty nice, I may hold out for a used set.

Yes, you will need bumps and straps. You do not want to use your shocks for either, it will ruin them. Type of bumps doesn't matter....much, but the air bumps are much easier on the parts and YOU! On straps, a general rule of thumb is...they stretch like a bungee chord around 1" for every 12" of strap length. Obviously the double and triple layer straps will stretch less, and a lot of racers run two or more straps on each corner, in case one get cut/chaffed/breaks.

Weight distribution. I'm clueless on this, but it seems like getting close to 50/50 would be good. I have gotten a bit of air in my XJ, and it's pretty obvious that it's front heavy when I'm coming down and can't see the horizon. Not sure how to accomplish this. No ridiculous front bumper or winch. Can't remove a lot of weight in the front. Spare tire in the back, of course, with other equipment?

The more weight you can relocat to the back the better. That's why a lot of the spare tire mounts extend beyond the rear bumper, batteries are relocated to the back, glass hood and fenders, remove windshield, remove dash, etc. Even a 50/50 weight bias will land nose first because of the trajectory and effects of gravity, but also depends greatly on jumping technique and what you do with the throttle on take off, and in flight. If you chop the throttle before your rear tires leave the ground, you'll endo every time.

Trussing. It looks like go-fast stuff means trusses under the axle, which will hurt for any crawling I may do, but is well worth it to keep things together. I would plan on keep the D30 for as long as possible, and I have a locked D44 in the works for the rear.

You can truss the top of the axles, but it stronger in tension on the bottom, rather than in compression on the top. Get a HD style diff cover for the D30 as well to keep the case from flexing. This is what causes most R&P failures in the D30.

Fenders. What is the deal with these, is it a JeepSpeed requirement to have your tires completely covered? I'm not sure I see the point, but I'm sure someone will enlighten me

Glass Fenders are not a requirement, but you're supposed to run the stock or aftermarket flares in jeepspeed, to keep it stockish looking. Retarded rule if you ask me.



Cliffs: What do I need to get started? Awesome shocks (with solid mounts, and in the cab if necessary) and quality springs are pretty much the first thing. Long arms, trusses, and better weight distribution are secondary things to look into.

You need to start with a solid foundation to make the unibody survive. Frame stiffeners, cage tied to the frame, through the firewall, engine compartment, all the way to the front of the uni-frame. If you dont do the engine cage with your interior cage, it will put a huge amount of leverage and stress on the front frame rails. Also tie the cage in to as many suspension pick up points as possible to keep the load off of the sheetmetal frame work. You'll need an overall plan for the suspension when you build your cage and stiffeners, so you don't have to go back and re-do stuff later.

Hope all this helps.

-Dan

He sounds like he has a pretty good grasp on it to me. Valving the shocks will play a big part in the handling(so rebuildable/revalvable shocks make a lot of sense), as will the weight bias. You will need to have the shocks through the floor to get any decent travel in the back. The resis help a whole bunch with pressure spikes so I would shoot for a set of those. Alot of the jeepspeeders run 2.5" bypasses front and rear, so a good set of 2.5" shocks will likely be fine for whatever you throw at it.

Don't limit yourself(unless you want to), I know there are some jeepspeeders from TX. You can build it to be JS legal and still have a good time not racing.

If you read through Skullver's build thread, you will see the progression and thought processes invloved.

WOW! Tons of great info here guys, I'm sure there are other noobs around who are looking for some good info to get started. Thanks Baja_XJ for your thoughts and getting others to come in and share their knowledge as well. I have to go to a wedding the weekend of the Jamboree, buy Casey is pretty close (<3 hours) so I don't really have an excuse not to go.

steed76, where do you work?

I'm coming to a realization based on what Loose Nuts said - as fun as it would be to throw some nice shocks and bumps on and start flying over the hills, I need to take a closer look at some of the boring stuff that I didn't mention in my first post. I don't have stiffeners or a cage. It seems like as much as I don't want to, those are things I need to get taken care of before I put a ton into suspension equipment. Easier/cheaper to keep the frame intact now instead of repairing it after the fact. I have been wanting a set of HD off-road stiffeners for a while, but my lack of welding skill is putting me off a bit. This might finally be the motivation I need to practice welding (have a 110v MIG, not the greatest but I at least need to learn some technique).

I have been keeping an eye on the race-dezert classifieds. I'm not in a huge rush, so if I find deals on pairs of shocks or a high-count leaf pack, I'll go for it.

Skullver, I like your suggestion to more or less follow JS rules. Like I mentioned I'm not planning on participating, but sometimes you start off with small ideas and next thing you know you're on the other side of the country. I have read through your build thread several times, also Loose Nuts' build thread, just seeing the cool stuff you guys are doing is pretty motivating by itself.

I'm sure I'll have more thoughts/questions later, just trying to process it all now.

dont quote me on this, cause i havent actually done the research..

but the main reason your front end is probably so heavy is because (if im right)

Your stock 4.0L is heavier than a 350, which is probably why its so damn reliable.

steed76, where do you work?


Carquest...

all i can say is stand by great thinkers and copy there work.

Swamprat said:

all i can say is stand by great thinkers and copy there work.

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COPY IT!!! lol you cheater. jk. but seriously




lol

GoSlowGetStuck said:

...,Skullver, I like your suggestion to more or less follow JS rules. Like I mentioned I'm not planning on participating, but sometimes you start off with small ideas and next thing you know you're on the other side of the country,...

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You'd be surprised how it can hook you.
If you're going to cage your Jeep,(a really good idea) build it, or have it built to a race spec. Even if you're not putting in all the bars, braces, gussets, etc, have the parts you put in (basic 6-point cage, restraint mounts, whatever), built to a regulation specification. 'Couple of reasons:
1) The race rules are what real world testing (and crashing) shows works
2)If you decide to go racing, you don't have to re-do what you've already done.
Here's a couple of links for you to look over:
Jeepspeed rules:http://www.jeepspeed.com/rules/rules.shtml
Best in the Desert rules:http://www.bitd.com/content/category/4/10/11/
FIA rules:http://argent.fia.com/web/fia-public.nsf/wcodj09?Openform&lang=a (Rally anyone?)
SCORE rules: http://www.score-international.com/

You'll find that most of the classes you can run an XJ in are suspension travel limited, and you can easily build a jeep that has much more then can be legally used. Not a big deal if you just want to play, but again, if the bug bites,...

This is always a fun build to look at if you're contemplating a go-fast XJ: JP magazine did a series article on Temper-Mental Racing's build in '06
Ignore the "10 day" bulls**t.(That's just JP being idiots)
overview
part 1
part 2
part 3
part 4

As far as shocks go, every racer I've talked to says something along the lines of; "Take your shock budget, double it, and that's your starting point." Any of the higher line manufacturer's non-resi. shocks will hold up to occasional blasts, but if(when) you go racing, you look in the rule book, and put the biggest shock they allow (damn rules,...)

Djmack said:

Your stock 4.0L is heavier than a 350, which is probably why its so damn reliable.

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Funny, I own two vehicles, one with each of those motors. And yes, when I replace the 4.0L in a few months I will be much more worried about putting it on the stand than I was with the 350 on there. Still, I will be stuck with the 4.0L (at least the block, though not that displacement) for a long time to come.

steed76 said:

Carquest...

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Cool, I didn't even realize Lafayette had one until a few weeks ago. It's not to far from work so I will stop in the next time I need parts.

Swamprat said:

all i can say is stand by great thinkers and copy there work.

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Imitation is the most sincere form of flattery. I think?

"Cool, I didn't even realize Lafayette had one until a few weeks ago. It's not to far from work so I will stop in the next time I need parts"

yeah alot of people don't! We cater more towards the commercial side.. but I'm always lookin to make new friends... especially when it comes to cars!