Get some UCAs, good coil overs valved properly, Wheeler's Super Bumps (cheap bottom out insurance), and a compressor. Air them tires down to about 15psi and that will soak up a good bit of the terrain you are describing. But, anything over 45 or 50 could be catastrophic without proper safety.

Keep in mind that most dirt roads don't have a good shoulder and trees are everywhere unless your in pasture land, then that is obviously more forgiving, although ditches are a serious hazard too. It doesn't take much to get out of shape and shit hurts a lot at 50+ mph. That Georgia clay gets slick as a greased pig too lol.

This is a video of my 4th gen V8 with a $4k (2018 prices) mid travel set up. C-rated 35" Tires aired down to 17psi. I think I topped 50 mph for a few seconds, but it's difficult to peep the speedo at those speeds because things are happening pretty quick. This is on a designated ohv power line road that's opened up a good bit, compared to a 2 lane dirt road. But there are side trails I slow down for to make sure no one is popping out on to the main. This past summer I've at least installed racing seats w 6 points and a harness bar. I don't have the money for a much needed cage unfortunately. Because I'm addicted to it now.

You can definitely get a 2.5” coilover body with reservoirs and mess with them a bit to get a better valving but realistically you’d want to go mid travel by getting the extended travel version with the internal spacer removed, which requires adding a quality performance UCA and limit straps.

Later on you could always get the aftermarket stock length lower control arms with a secondary shock mount and add a hydro bump or even a double/ triple bypass (with a TC coil bucket or similar tower mount added) as the budget allows over time. That’s going to far exceed the cost of basic long travel kit with 8” coilovers so really it’s going to cost you north of $4k either way.

I think 2.5” coilover for now and adding a set of durobumps will definitely increase your control and comfort in the speeds your current setup feels sketchy. That’s probably $2k new right there though. Honestly, paired with the rear shocks you have, it will perform pretty damn well on a fire road at speed.

It really depends on what your goal is for performance. The biggest thing I noticed from a 3.5” LT kit is how much more stable it was than just a pair of quality 2.5” coilovers. That wider stance is a real game changer with stability.

What’s a flutter valve and how do you get the setup you’re talking about? I’d love to know more about it

I'm just learning this stuff, and I know there are way more qualified people to comment on this, but here is a picture of a flutter valve set up that I took out of my rear smoothies. It was just too light of valving for the weight I have on my 4th gen. I think there are quite a few variations of this type of setup depending on terrain, driving style, suspension capabilities, vehicle weight, etc. Bleed holes are a thing too. I've read good things about the Fox DSC reservoirs also. Spend a little time on AccuTune's tech page and it might help a little.

Attached Images

   

The best cheap option is

-Bilstein 6112 shocks up front
- air down some very strong C rated tires
-good sway bar link setup adjusted properly
-5160 Bilstein rears
- whatever rear spring (2890 ome gives me way more rear travel before hitting the Duro bumps.
-Duro bumps
-sort out the panhard bar once above 1.5-2" lift.

Your in the $1500-$1700 ish range I'd say with those parts. I can rally rough fire roads in the 40 to 60 mph range pretty easily. That's going to be as good as you can go without getting too far in the custom parts and that will still keep it a regular-ish vehicle.

Beyond that, things get a lot more complicated and way more expensive.

I'm going to probably say something that may not resonate well here. But if your goal is truly extremely high speed, I think you have the wrong machine. You need, most likely a side-by-side with some awesome travel and power. Even long traveled out 3rd gen or 4th gen with extra power, is still not going to perform like a Can-Am or a razor. It's the power to weight ratio always that determines the outcome.

Go find a used or new side by side, get it financed on the cheap and go rally.

If your requirement was hey, I need a full body vehicle with air conditioning, five seats, I want to do some spirited offloading, maybe some crawling, and still have space for luggage, then yeah, you have the perfect rig.

But a full body rig for the all out speed rally..... naw. It'll never deliver on your expectations. Get a turbo side by side. Once you need beyond the factory suspension capability seek out the companies that can do better. My neighbor spent $4000 on valving and springs for his to 2 seat can am turbo. It's a monster. Quite literally eats large bumps like nothing. Bumps that would break my 4runner in half at 65. Of course, he used to race stock cars, has a basement full of trophies, and wasn't too sad when he wrecked the roll cage on it and we put a new one on. So there's that I guess. But he also goes to Yuma Arizona in the winter time and they will rally their side-by-side's into Mexico doing hundreds of miles per day of road. They run the helmet radios, neck braces and the whole bit.

If speed is what you are really after, I think you are wasting your time with a 3rd gen 4runner. I say this as a guy that absolutely loves 3rd gens as it is probably my favorite vehicle.

I do wish it had power like my 2023 tundra through. That damn thing launches like a roller coaster.

Off-Road Shock Tuning Guide | How To Tune and Valve Off-Road Racing Shocks

For sure, I totally understand and I think for baja 1000 type driving the 3rd gens would be like how the stock beetle class would be lol. That just isn't the type of terrain I'm on though. just long straight washboard roads. I can get up to the desired speed I want, it's just the 5100's up front are terrible. out back I have OME 890's on Fox 2.0x12 Reservoir shocks. Rear end is keeping up just fine it's just the front end that's garbage. I have a dirt bike for crazier things, but I just wanted to spice up the daily.

For flat dirt roads through pine forests? Some kind of rebuildable 2.5" coilover, UCAs, durobumps, and like 25psi in your tires ought to get you into plenty of trouble.

Just watch out for holes appearing out of nowhere - you're still rocking basically a stock suspension.

Definitely going on a low speed sweep before giving it the goose for anything that could mess me up. Got the UCA's, I need new bumpstops anyways so that's a good thing to know. Would 2.5's be to stiff for essentially stock weight? Or is it just more oil capacity for more cooling, and spring rate and valving have the most impact on that.

That "whrrrrTHUMP-THUMP" sound of slamming the brakes too late is burned into my brain

Yeah the 2.5" vs 2" just gives you more oil for better shock cooling. I'm sure the bigger diameter piston helps with damping too, but I won't claim to know anything about that. Spring rate is going to have a much bigger effect on how stiff the ride is. If you're really concerned with shock tuning, you might consider buying your shocks through someone like Accutune. I have off the shelf Kings with 600lb springs that I think ride great.

If you end up shelling out the cash for fancy coilovers, make sure they're rebuildable, like King or Fox. For as much money as they cost, anything that isn't rebuildable is going to end up costing you double (looking at you, Toytec).

haha yep, been there too.

Get a better front coils and some Duro bumps and call it a day then. I really have enjoyed my 6112's so far.

Hey bud, all great responses. I only want add that you might want to think about the abs on these rigs, it’s primitive and has caused issues before. Hope you enjoy the machine and the outdoors.

Oh for sure. I'd definitely want to go Fox (just because I like the DSC) from Accutune because of the custom tune like you mentioned if I can afford it. I'll have to read up on 2.0 vs 2.5, but if I can afford it, I'll be getting the best (buy once cry once).

Ok, that's really good insight. Less than $800 for 2.5's is very decent.

For sure man, I've actually removed the ABS feature for this reason. It almost messed me up and I've only driven vehicles without ABS, so I know how to brake without it for sure. Enjoying the machine and outdoors are why we do what we do haha

Curious if everyone's input here would also apply to moderate speeds on dirt roads? I do a lot of under 40mph driving, and the car feels like it is about to shake into a million pieces on washboards. I suspect the Bilstein 4600 are largely to blame.

@thezentree how do you kings feel on washboards?