Improving Off road capability in AHC equipped AHC

[ClassyJalopy]

OP, what year is your 100? I completely disagree about lockers if you have ATRAC and want "just a little more offraod capable" that is good to go in "soft sand, snow, mud etc. only".

ATRAC works great, but IMO the biggest limiting factors on the 100 is ground clearance...it's nonexistent compared to my 4th gen 4Runner. And the cheesy plastic "engine cover" (wanna be skidplate) under the LX...wth is that? Can't imagine what running aired down does there.

My observations based on owning both an '04 V8 4Runner, and an '06 LX 470 the past 15+ years. My 4Runner has been all over Death Valley and Panamint Valley and a few places in Eastern Sierra. That's with a mild lift and slightly larger tires (265/70/17) still on stock wheels, Hanna sliders and a Shrockworks front bumper. I've barely offroaded the LX as it's the wife's pavement princess but there's no hiding the weak atributes of its poor ground clearance and poor underbelly protection.

I'm in the same boat as wanting to get my 100 at least slightly more offroadable. I'm hoping that going up to one of the largest size tires that'll fit on the factory wheels, and proper skid plates, will be all I'll need for my intended purposes of a few nights of camping/trail-running at a time. Will likely add step-sliders too. I'm hoping that the exta lift the AHC offers in 4WD will help tons on the ground clearance. Add Staun deflaters and an air tank or battery tire inflater and you should be good to go in "n soft sand, snow, mud etc. only."

Wut!? Dude you are comparing a lifted truck with aftermarket protection with a stock 100 and complaining abt ground clearance and underbody protection

 

[dealmaker]

Wut!? Dude you are comparing a lifted truck with aftermarket protection with a stock 100 and complaining abt ground clearance and underbody protection

Did you read OP's intended use?? And...tbh 2 inches on a 4th gen isn't much of a lift really, it just brings it back to where the previous 4Runner generations were in terms of heigth and tire size (my upsized tires are only 32" tall)..and as for my aftermarket protection, nice for rocks but it's pretty useless in sand, snow and mud except for additional recovery points, but yeah I'm complaining about a plastic "engine cover" where there should really be a real skid plate, especially for a truck that was more than twice the cost. But really, I'm explaining to him that for his intended use of going "in soft sand, snow and mud only", if he has ATRAC then his $ is probably better spent elsewhere than lockers for his intended use, based on where my ATRAC-equipped truck has gotten me on 32" tires with better ground clearance.

 

[kreiten]

Deep sand, up in the mountains camping or doing the Rubicon, the 4 mods I use all the time are, bigger/better tires, sliders, air compressor and rear locker! Just my 2 cents from my experiences...

 

[hoser]

My observations based on owning both an '04 V8 4Runner, and an '06 LX 470 the past 15+ years. My 4Runner has been all over Death Valley and Panamint Valley and a few places in Eastern Sierra. That's with a mild lift and slightly larger tires (265/70/17) still on stock wheels, Hanna sliders and a Shrockworks front bumper. I've barely offroaded the LX as it's the wife's pavement princess but there's no hiding the weak atributes of its poor ground clearance and poor underbelly protection.

IMO, on the 100, most of the drivetrain is position above or not much lower than the frame rails. I've only wheeled with a couple of 4th Gen 4Runners but when I spot them, all I see is that transmission crossmember that hangs low and the gas tank is more exposed as well. Clue me in? What ground clearance on the 100 is so inferior to the 4runner?

Personally, I think a 100 with 33's, stock height and sliders can travel 95% of all Death Valley and not have issues. It doesn't even need skid plates for mild to moderate terrain.

 

[jLB]

ATRAC works great, but IMO the biggest limiting factors on the 100 is ground clearance...it's nonexistent compared to my 4th gen 4Runner. And the cheesy plastic "engine cover" (wanna be skidplate) under the LX...wth is that? Can't imagine what running aired down does there.

My observations based on owning both an '04 V8 4Runner, and an '06 LX 470 the past 15+ years. My 4Runner has been all over Death Valley and Panamint Valley and a few places in Eastern Sierra. That's with a mild lift and slightly larger tires (265/70/17) still on stock wheels, Hanna sliders and a Shrockworks front bumper. I've barely offroaded the LX as it's the wife's pavement princess but there's no hiding the weak atributes of its poor ground clearance and poor underbelly protection.

Interesting perspective.

I owned an 04 T4R V8 4x4 limited from 2004-2014. It replaced a 94 80 series, that I had owned 10 years as well. I owned multiple 100 series concurrently with the T4R, and still own 3.

Admittedly, most of my 100 series were LXs with “uppy-downy buttons” (AHC), but I don’t remember the T4R having a significant advantage in ground clearance.

I don’t remember the T4R having beefy skid plates from the factory, or protecting the underside exceptionally well.

Or were you suggesting, that the modifications that you’ve chosen to make to your personal T4R, have made a massive improvement, and you’d suggest doing the same on a 100 series for a similar improvement?

 

[dealmaker]

IMO, on the 100, most of the drivetrain is position above or not much lower than the frame rails. I've only wheeled with a couple of 4th Gen 4Runners but when I spot them, all I see is that transmission crossmember that hangs low and the gas tank is more exposed as well. Clue me in? What ground clearance on the 100 is so inferior to the 4runner?

Personally, I think a 100 with 33's, stock height and sliders can travel 95% of all Death Valley and not have issues. It doesn't even need skid plates for mild to moderate terrain.

Try working underneath a stock LX470 with 32" tires, and a mildly-lifted 4th gen with 31.6" tires, and you'll definitely see, and feel, the difference as I have many times. Sure, the difference may not matter when running trails with sliders and a good spotter, but the difference is still there. You're right about the 4th gen crossmember anbd the gas tank. I think the 4th gen designers were still shellshock over the Ford Exploder incident when they designed the 4th gen.

It should, my '04 4Runner did and that's what I'm counting on for my LX. With 33's and "stock AHC height" in 4WD the LX should have more ground clearance than my '04 4Runner.

 

[hoser]

Well, does your wife's LX still have running boards? Because that would make a huge difference. When working underneath my LX, I sometimes put the AHC in HIGH for extra clearance.

If you get a chance, can you put your LX in HI mode and measure and compare the differences in ground clearance?

 

[dealmaker]

Interesting perspective.

I owned an 04 T4R V8 4x4 limited from 2004-2014. It replaced a 94 80 series, that I had owned 10 years as well. I owned multiple 100 series concurrently with the T4R, and still own 3.

Admittedly, most of my 100 series were LXs with “uppy-downy buttons” (AHC), but I don’t remember the T4R having a significant advantage in ground clearance.

I don’t remember the T4R having beefy skid plates from the factory, or protecting the underside exceptionally well.

Or were you suggesting, that the modifications that you’ve chosen to make to your personal T4R, have made a massive improvement, and you’d suggest doing the same on a 100 series for a similar improvement?

I don't recall a factory 4th gen having any ground clearance advantage. Design-wise it was the reject of 4Runners. Only saving grace IMO was the 2UZ-FE and 4WD in a $32k package that was Made In Japan.

I still have the flimsy metal factory skids. They're beat-up from fun in DV/PV. Maybe the plastic engine cover would hold up better? How much heavier is a 100 than a 4th gen? Yeah, skids are probably irrelevant in sand. snow and mud, but my guess is the slippery slope of offroad fun and exploring will lead him to rocky trails soon enough, and for that IMO one would be better off to have a solid skid plate set. To be sure, most AM skids reduce GC, but one has to decide on the cost/benefit there. Just driving the freeways I've seen enough ladders, BBQs, wheels, etc. in traffic lanes to think a good skidplate upgrade is worthwhile.

I was suggesting that instead of throwing out big bucks for something like lockers right now, his ATRAC or RR locker should be fine for his intended purposes of sand, snow and mud, and that he should focus on increasing ground clearance and a better skidplate setup, and airdown/airup and recovery stuff. With AHC he gets the mild lift for free. My reference to my 4Runner was for example's sake that my increase (not a big one) in tire size and a 2" lift, gave what I deem is a significant increase in ground clearance over factory and made it what it should've been out of the factory. To me, 1.5-3 inches of gained ground clearance is a big deal and I probably got at the top of that range in my 4th gen with my mild mods. IMO the only "massive" improvement I made to my 4th gen was the front bullbar...the 4th gen is an approach angle bummer. I can't even move up to 32" tires because it won't fit in the spare location...that's how bad the design was.

 

[TreatSmash]

Well, does your wife's LX still have running boards? Because that would make a huge difference. When working underneath my LX, I sometimes put the AHC in HIGH for extra clearance.

If you get a chance, can you put your LX in HI mode and measure and compare the differences in ground clearance?

Haha I don't even think about getting under my truck if its not in high.

 

[GTV]

I don't recall a factory 4th gen having any ground clearance advantage. Design-wise it was the reject of 4Runners. Only saving grace IMO was the 2UZ-FE and 4WD in a $32k package that was Made In Japan.

I still have the flimsy metal factory skids. They're beat-up from fun in DV/PV. Maybe the plastic engine cover would hold up better? How much heavier is a 100 than a 4th gen? Yeah, skids are probably irrelevant in sand. snow and mud, but my guess is the slippery slope of offroad fun and exploring will lead him to rocky trails soon enough, and for that IMO one would be better off to have a solid skid plate set. To be sure, most AM skids reduce GC, but one has to decide on the cost/benefit there. Just driving the freeways I've seen enough ladders, BBQs, wheels, etc. in traffic lanes to think a good skidplate upgrade is worthwhile.

I was suggesting that instead of throwing out big bucks for something like lockers right now, his ATRAC or RR locker should be fine for his intended purposes of sand, snow and mud, and that he should focus on increasing ground clearance and a better skidplate setup, and airdown/airup and recovery stuff. With AHC he gets the mild lift for free. My reference to my 4Runner was for example's sake that my increase (not a big one) in tire size and a 2" lift, gave what I deem is a significant increase in ground clearance over factory and made it what it should've been out of the factory. To me, 1.5-3 inches of gained ground clearance is a big deal and I probably got at the top of that range in my 4th gen with my mild mods. IMO the only "massive" improvement I made to my 4th gen was the front bullbar...the 4th gen is an approach angle bummer. I can't even move up to 32" tires because it won't fit in the spare location...that's how bad the design was.

The lowest point of the vehicle is the bottom of the rear differential. Therefore the only way to gain 1.5-3 inches of ground clearance is to use tires that are 3-6 inches taller. Ground clearance does not change with a suspension lift.

 

[dealmaker]

Well, does your wife's LX still have running boards? Because that would make a huge difference. When working underneath my LX, I sometimes put the AHC in HIGH for extra clearance.

If you get a chance, can you put your LX in HI mode and measure and compare the differences in ground clearance?

Haha I don't even think about getting under my truck if its not in high.

Are you calling me fat?



Yes, still has the pita running boards as it's still my wife's even tho she's driving my daughters T4R. And admittedly, it took awhile before I realized there's 3 degrees of High the AHC can reach. Recently I've come to the conclusion that I may be better off working harder and just paying others to crawl underneath. Problem is, I'm OCD and I started spending too much time on MUD again and have trust issues with most mechanics.

The lowest point of the vehicle is the bottom of the rear differential. Therefore the only way to gain 1.5-3 inches of ground clearance is to use tires that are 3-6 inches taller. Ground clearance does not change with a suspension lift.

Minimum ground clearance is what you speak of. I'm speaking of the other 99% of the underneath.

 

[Moridinbg]

The most overlooked limiting factor is the torsion bars IMHO. Everybody keeps telling that you put a few turns and you are good, but that is simply not true. Tightening torsion bars does nothing other than adding preload. In the end it's a simple spring, just not coil shaped. Increasing preload makes it take more force before it starts compressing (twisting), but it doesn't change the spring rate. Once it start compressing, it goes through the range like it's nothing. Adding a lot of weight in front (winch, bumper, RTT) and just tightening the torsion bar completely screws damping, especially when pointing downhill and having most of the weight over the front axle.

Right now I am at about 7200-7300lb with all the expedition kit (diesels are also a good deal heavier to begin with). LC80 springs keep pressure in the rear in check and I have adjusted the torsion bar so that I am at about 7.2MPa with all the gear, fuel and water. The front suspension keeps bottoming out, especially going downhill. Without all the expedition junk, at stock weight and again 7.2MPa I have to really push it to bottom out.

I really really wish I had non-AHC torsion bars, but in Europe we don't have LXs and all the LC 98-07 are AHC equipped so they are extremely hard to get. Petrol torsion bars are also a different length than diesel.

I also have had a sensor s*** itself two times on the trail - that is not fun. Everybody is afraid that when the system fails they will be on bump stops, but let me tell you, when the sensor tells the ECU that the rear axle is at -1498mm and it pumps the shocks all the way to the top it is pretty much an undrivable pogo stick and there is nothing you can do about it. Now I always carry a spare sensor. At least the 3 are interchangeable when removed from the bracket.


Other than that it's an awesome system and I would never switch it for conventional suspension that is only good either on the road or off it.

 

[jLB]

Design-wise it was the reject of 4Runners. Only saving grace IMO was the 2UZ-FE and 4WD in a $32k package that was Made In Japan.

I talked myself into “drivetrain of a 100 series, at a significantly reduced cost”, and quickly regretted that decision. At least the navigation system was a relatively easy to replace double DIN.

I still have the flimsy metal factory skids. They're beat-up from fun in DV/PV. Maybe the plastic engine cover would hold up better? How much heavier is a 100 than a 4th gen? Yeah, skids are probably irrelevant in sand. snow and mud, but my guess is the slippery slope of offroad fun and exploring will lead him to rocky trails soon enough, and for that IMO one would be better off to have a solid skid plate set. To be sure, most AM skids reduce GC, but one has to decide on the cost/benefit there. Just driving the freeways I've seen enough ladders, BBQs, wheels, etc. in traffic lanes to think a good skidplate upgrade is worthwhile.

When first got my 80 series, I spent way too much time/effort/money equipping my vehicle, like the ones in Australia, before getting out and using it. Now that I’m older/wiser, I prefer starting with tires, sliders, with a handful of gear in back, and addressing issues/shortcomings as you come across them.

Funny you should mention “ladders” and T4R…. I ran over a ~6ft A-frame fiberglass ladder, in my T4R, when it fell out of a pickup going the other direction. No real body damage, but it happened much differently than I would have expected. One side trapped the passenger front tire, lifting it off the ground. The ladder then twisted 180* and trapped the driver front tire, lifting it off the ground. Presto! No steering . It was an interesting challenge getting the ladder out from under the vehicle, with the factory jack.

I was suggesting that instead of throwing out big bucks for something like lockers right now, his ATRAC or RR locker should be fine for his intended purposes of sand, snow and mud, and that he should focus on increasing ground clearance and a better skidplate setup, and airdown/airup and recovery stuff. With AHC he gets the mild lift for free. My reference to my 4Runner was for example's sake that my increase (not a big one) in tire size and a 2" lift, gave what I deem is a significant increase in ground clearance over factory and made it what it should've been out of the factory. To me, 1.5-3 inches of gained ground clearance is a big deal and I probably got at the top of that range in my 4th gen with my mild mods. IMO the only "massive" improvement I made to my 4th gen was the front bullbar...the 4th gen is an approach angle bummer. I can't even move up to 32" tires because it won't fit in the spare location...that's how bad the design was.

I personally would probably place “sliders” above “skid plates”, but that may vary by region or usage, otherwise I generally agree.

Similar to the 100 series ~33” limit.

 

[willyroo]

I don't intend doing anything extreme so I am looking for the changes that will stop me getting stuck in soft sand, snow, mud etc. only.

Previously owned a 2007 UJZ100 LC, with 2" lift, Dobinson springs/torsion bars, airbag man rear airbags for trailer, and Ironman Foam Cell Pro shock absorbers. Due to premature death (problem was between seat and steering wheel unfortunately), I parlayed the insurance cheque into a mint 2007 LX470.

The only mod done was to install the King Springs KTRS-89, which help the AHC with our ~180kg (~400lb) tow ball weight camper trailer.

So far, over sand - including really soft stuff - on Fraser/K'gari Island, I found the LX better off road than the LC. And the (modified) LC was already really good in the tough stuff.

That's my n=1 (2?)

 

[dealmaker]

Previously owned a 2007 UJZ100 LC, with 2" lift, Dobinson springs/torsion bars, airbag man rear airbags for trailer, and Ironman Foam Cell Pro shock absorbers. Due to premature death (problem was between seat and steering wheel unfortunately), I parlayed the insurance cheque into a mint 2007 LX470.

The only mod done was to install the King Springs KTRS-89, which help the AHC with our ~180kg (~400lb) tow ball weight camper trailer.

So far, over sand - including really soft stuff - on Fraser/K'gari Island, I found the LX better off road than the LC. And the (modified) LC was already really good in the tough stuff.

That's my n=1 (2?)

The wife lived in AUS for 5 yrs, Brisbane. She's always telling me about camping at Fraser Island. Sounds incredible. One day I'll make it out there and see for myself.

 

[dealmaker]

I talked myself into “drivetrain of a 100 series, at a significantly reduced cost”, and quickly regretted that decision. At least the navigation system was a relatively easy to replace double DIN.



When first got my 80 series, I spent way too much time/effort/money equipping my vehicle, like the ones in Australia, before getting out and using it. Now that I’m older/wiser, I prefer starting with tires, sliders, with a handful of gear in back, and addressing issues/shortcomings as you come across them.

Funny you should mention “ladders” and T4R…. I ran over a ~6ft A-frame fiberglass ladder, in my T4R, when it fell out of a pickup going the other direction. No real body damage, but it happened much differently than I would have expected. One side trapped the passenger front tire, lifting it off the ground. The ladder then twisted 180* and trapped the driver front tire, lifting it off the ground. Presto! No steering . It was an interesting challenge getting the ladder out from under the vehicle, with the factory jack.




I personally would probably place “sliders” above “skid plates”, but that may vary by region or usage, otherwise I generally agree.

Similar to the 100 series ~33” limit.

Seriously? I love my 4Runners, especially the '04 4WD that I bought new. Comparing to a 100 back then never crossed my mind as I didn't follow LCs closely then. I had 1st and 2nd gens and always thought "if they just made it a little bigger and a little more powerful it would be perfect." Then life happened, but one day in 2004 I saw a billboard advertising the 4th gen w/V8 and was intrigued. Test drove and bought on the spot. Size was perfect, at the time, as my kids were 4 and 6. Bought the LX in 2009 from a friend, so when the kids grew and we needed more room, got a dog, etc. we never had to rely on the 4th gen as the family travel vehicle, otherwise I'd probably feel different about it. But when I go out in to the great outdoors solo or w/my son, it's the go-to truck. Reliability has been insane. Literally zero fail issues other than the brake booster last month. Meanwhile, the LX is on its 3rd alternator, 2nd radiator, 2nd SAIP, a couple of stuck brake calipers, about to get its 2nd starter, and mechanic says rear main seal leak and leaking R&P...for sure a more complex vehicle and more $ to maintain, but the bigger greenhouse, better seating and overall comfort level and handling with the adjustable suspension dampening is amazing.

I agree about the slippery slope of mod$. Didn't mention sliders because OP said he's already committed to them. For my own ideas for our LX I'm thinking 275/70/18 KO2 on OEM wheels and possibly Dissent alum skids and Owl Step Sliders...gottta see if they're available and mount around the AHC stuff. I'd like an alum bullbar too but that probably won't happen.

 

[jLB]

Seriously? I love my 4Runners, especially the '04 4WD that I bought new. Comparing to a 100 back then never crossed my mind as I didn't follow LCs closely then.

Yep, but I also came from a 80 series, and had rather high expectations. I had mom’s 03 GX470, and dad’s LX470 to compare it to as well. My 04 T4R was a transportation appliance to me, my 80/100 series have been “more than that”. I tried to give the T4R to my son, when he got to driving age, but he wanted my 06 LX, and suggested that we trade the T4R for a 200 series for me. Sorry kid, but I did find a (used) 00 LC for him.

 

[JJ_SC]

For what it’s worth, I’ve run almost all of Death Valley and a lot of the Eastern Sierra in my 100 while it was still basically stock. It had 33s. Never came close to getting stuck. Never had ground clearance issues. Mengle Pass, Steel Canyon, Chicken Rock… all the “hard” places. Really no big deal.

I’ve done mods and changes over time. Harder stuff in other places. But, if Death Valley is your destination - just go.

 

[ClassyJalopy]

The most overlooked limiting factor is the torsion bars IMHO. Everybody keeps telling that you put a few turns and you are good, but that is simply not true. Tightening torsion bars does nothing other than adding preload. In the end it's a simple spring, just not coil shaped. Increasing preload makes it take more force before it starts compressing (twisting), but it doesn't change the spring rate. Once it start compressing, it goes through the range like it's nothing. Adding a lot of weight in front (winch, bumper, RTT) and just tightening the torsion bar completely screws damping, especially when pointing downhill and having most of the weight over the front axle.

Right now I am at about 7200-7300lb with all the expedition kit (diesels are also a good deal heavier to begin with). LC80 springs keep pressure in the rear in check and I have adjusted the torsion bar so that I am at about 7.2MPa with all the gear, fuel and water. The front suspension keeps bottoming out, especially going downhill. Without all the expedition junk, at stock weight and again 7.2MPa I have to really push it to bottom out.

I really really wish I had non-AHC torsion bars, but in Europe we don't have LXs and all the LC 98-07 are AHC equipped so they are extremely hard to get. Petrol torsion bars are also a different length than diesel.

I also have had a sensor s*** itself two times on the trail - that is not fun. Everybody is afraid that when the system fails they will be on bump stops, but let me tell you, when the sensor tells the ECU that the rear axle is at -1498mm and it pumps the shocks all the way to the top it is pretty much an undrivable pogo stick and there is nothing you can do about it. Now I always carry a spare sensor. At least the 3 are interchangeable when removed from the bracket.


Other than that it's an awesome system and I would never switch it for conventional suspension that is only good either on the road or off it.

This is very helpful insight. I am noticing that after re-indexing the AHC specific TBs I am able to get the static AHC pressures in range but they really don't provide much resistance to bottoming out and in general be very bumpy under load. @Moridinbg nailed this perfectly - the TBs are over stressed and need to be uprated for heavier load.

Quite interestingly I had a similar issue with my non-AHC 98, once I build it up with heavier stuff. The non-AHC TBs were able to hold the truck up when static but weren't able to handle the dynamic load very well and that caused the ride to suffer badly. Heaver gauges TBs remedied that!

Time to look for LC torsion bars!

 

[hoser]

I know @Moridinbg stated he had an HDJ100 with the diesel... but just to restate it because the difference is very significant, maybe 250-300 lbs of extra weight on the front end. The HDJ100's in Australia commonly break their front lower control arms due to bottoming out, even with uprated torsion bars. That's why those LCA reinforcement brackets were designed. Very few in the US have cracked their arms, maybe 1-2 mentions on this forum and one of those had aftermarket lower control arm.