LX570 AHC height modifications (lift it!) (1 Viewer)

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Some TLC are running 35”x12.5x17 ridge grapplers. These are 34.76”. They are typically using two inch suspension lift.
35.3 is about 0.25” more than that. Should be fine in high mode which is more than 2” suspension lift. Will need to see for N mode. It will be close.
 
@DeckerT4R looks like your truck is back for sale


1966480
 
Read through the thread. Planning to sensor lift both the front & rear, but am still unclear about which, specific spacers I need for the rear.

I took out the rear seats, added drawers with some permanent gear, and am probably around 100-150lbs heavier than stock configuration.

Can anyone provide a part number (or link) for appropriate rear spacers which would lower the AHC load after lift? (I saw Trail Tailor spacers mentioned, but don't see anything on their website.)
 
Has anyone noticed the ride firmed up a bit after doing this sensor lift? I put on 275-70-18 E Rated BFG KO2s on the same day I did the sensor lift.

It’s not too harsh, but I am feeling most bumps now. Certainly very little brake dive now.
 
AFdude said:
Has anyone noticed the ride firmed up a bit after doing this sensor lift? I put on 275-70-18 E Rated BFG KO2s on the same day I did the sensor lift.

It’s not too harsh, but I am feeling most bumps now. Certainly very little brake dive now.
Click to expand...

Not me. Where your previous tires E rated?
 
AFdude said:
Has anyone noticed the ride firmed up a bit after doing this sensor lift? I put on 275-70-18 E Rated BFG KO2s on the same day I did the sensor lift.

It’s not too harsh, but I am feeling most bumps now. Certainly very little brake dive now.
Click to expand...
What PSI are you running?
 
tbisaacs said:
Not me. Where your previous tires E rated?
Click to expand...
Not sure whatever the stock 21” were. Probably C or P.

Also, I know the car is new to me so I’m not familiar with all the nuance, but it seems that AHC, when going down, is very quick, like quicker than I can recall. Is it just me? Not a complaint. Just an observation.
 
AFdude said:
Not sure whatever the stock 21” were. Probably C or P.
Click to expand...

More likely due to the tires. E-rated are much stiffer than a P or C rated tire. 2 ply sidewall, 10 ply tread.
 
So I'm looking to height adjust my LX. First I want to calibrate/offset the AHC system. "Active Height Control Suspension Initialization"

I'm looking at the steps and it makes sense up to step K. In step K you jack the car to put the readings into spec. I can do that. But in Step L, it looks like they want before and after. So is that the before jacking (step J), and the after jacking (Step K) measurements as inputs into Step L?

(j) Perform the vehicle height inspection.
Measuring points:
A
Ground clearance of front wheel center
B
Ground clearance of the front adjusting cam bolt center
C
Ground clearance of the rear axle shaft center
D
Ground clearance of the rear lower control arm front side center
Standard Vehicle Height:
FRONT (A MINUS B)​
REAR (C MINUS D)​
101 mm (3.98 in.)​
94 mm (3.70 in.)​
C171986E01-A.png
(k) Using a jack, set the vehicle to the standard vehicle height and eliminate any difference in height between the left and right sides of the vehicle.
NOTICE:
The vehicle height may be outside the calibration range if there is a difference in height between the left and right sides of the vehicle.

l) Using the Techstream, enter the following menus: Chassis / AHC / Data List. Then read and record the values for "After Height Adjust" and "Height Adjust" for each wheel.
 
Played with the height offset entry today in tech stream. Tried an array of real and fake values. Occasionally got an adjustment I could feel, but didn’t really get the rig any more balanced than it started.

I didn’t do any jacking. . .

Backstory- my rig came used to me with a pretty good left right and front back imbalance. The right rear is highest and left front lowest. My goal was to raise the left front and decrease the right rear.

So you can totally lie to the height control, however it kind of keeps track of the entered value and previous entered value, and won’t let these differ by more than 0.8, and also won’t them differ from the standard value by more than 0.8.

I think the answer to my setup is to start entering fake standard values to get increased difference value left to right and front to back. I will do some modeling in a spreadsheet and see what makes sense now that I’ve played with it a bit.

The other option is to increase the physical height sensor levers. This is less attractive to me as the right rear is already too tall, so the final setting in that case would be all corners higher than offset balancing would result in.

It may be academic with the 35s (ie i probably need to lift anyway in N)
 
Ok. This is interesting. I left the car for 20 min. Came back and made a short drive. Noticed my alignment was slightly off, and noticed that the left. Front seemed higher than usual. Got to the destination and Eureka! Wheel center to fender measurements are spot on all four corners! Previously the diff was around 1.5 inch R.R. to FL.

I wish i better understood what the dynamic was that leveled it out, and I am skeptical it will be permanent.

However if it sticks amazing!
 
I will note that the parking space I was parked in had was pretty pitched and back to front and Right to left . Ie exactly right to offset the starting lean

Hypothesis: the offset entries are to set new zero and the jacking is the actual up down that each corner makes. Since I was in a tilted parking space this was perceived as jacking.

Really wish there. Was more data out there on how the offsets interact with the sensor measurements

Final tidbit I did not zero calibrate the skid or g sensors
 
Did the AHC lift yesterday, and went for a couple hundred KM drive today. LX is noticeably less stable in the corners. Quite a bit more sway/body roll.

I think I'll bring it back down to OEM height...

But I do have those 30mm rear spring spacers still sitting here. Any harm/advantage to installing them? I figure the extra preload will take some pressure off the AHC shocks, which will come in handy when I'm towing my small (sub 2000lb loaded) off-road trailer, and especially so when in Hi mode with the trailer.

Any thoughts on installing them while keeping stock ride height?
 
I am at stock ride height and have added 20mm spacers to the rear. No detrimental affects that I have noticed.

I started out with 10mm for the extra load capacity to tow my Airstream with and 6 people in the vehicle. Tongue weight a bit over ~1000lbs. Plus 4 adults and 2 kids at ~680 lbs. Plus about 200lbs of gear. So about 1900lbs worth of payload. Worked dandy.

Since I've added an LRA 12.5 gallon subtank weighing in at ~200lbs filled, I've noticed AHC won't as readily go fully into high mode. It will lift higher, but not enough to register full "H" on the console. To be expected as this puts me right over 2000lbs payload.

Not bad for "malling suspension" that still rides buttery even with 71lb load range E tires (@36psi).

I've since replaced the spacer for 20mm worth of spacer total. Still at stock ride height. It now lifts more reliably under all that payload.

@eatSleepWoof, if you are doing any AHC lift at all, I would think a 30mm would be perfect. How much did you lift it yesterday? Lift enough, and you'll want to get an alignment as toe and caster will change enough to effect handling. Personally, I'm very critical of suspension and handling as I use to road race, so I put a priority on good suspension geometry and handling (even though she's a pig).

Too much lift, besides the stability lost due to the increased center of gravity, will cause weird jacking forces from the front IFS suspension and rear solid axle panhard bar. Lift also reduces the front track width as the control arms droop more pulling in the tires. It also causes a bunch of funny toe steer as the suspension cycles. None of that is for me. Besides, the suspension can lift sky high on demand anyways.
 
TeCKis300 said:
I am at stock ride height and have added 20mm spacers to the rear. No detrimental affects that I have noticed.

I started out with 10mm for the extra load capacity to tow my Airstream with and 6 people in the vehicle. Tongue weight a bit over ~1000lbs. Plus 4 adults and 2 kids at ~680 lbs. Plus about 200lbs of gear. So about 1900lbs worth of payload. Worked dandy.

Since I've added an LRA 12.5 gallon subtank weighing in at ~200lbs filled, I've noticed AHC won't as readily go fully into high mode. It will lift higher, but not enough to register full "H" on the console. To be expected as this puts me right over 2000lbs payload.

Not bad for "malling suspension" that still rides buttery even with 71lb load range E tires (@36psi).

I've since replaced the spacer for 20mm worth of spacer total. Still at stock ride height. It now lifts more reliably under all that payload.

@eatSleepWoof, if you are doing any AHC lift at all, I would think a 30mm would be perfect. How much did you lift it yesterday? Lift enough, and you'll want to get an alignment as toe and caster will change enough to effect handling. Personally, I'm very critical of suspension and handling as I use to road race, so I put a priority on good suspension geometry and handling (even though she's a pig).

Too much lift, besides the stability lost due to the increased center of gravity, will cause weird jacking forces from the front IFS suspension and rear solid axle panhard bar. Lift also reduces the front track width as the control arms droop more pulling in the tires. It also causes a bunch of funny toe steer as the suspension cycles. None of that is for me. Besides, the suspension can lift sky high on demand anyways.
Click to expand...

I actually bought the 30mm spacer based on your earlier posts :).

I got 1 1/4" out of the sensor lift.

Do you figure there would be any downsides to installing the 30mm spacer at stock ride height? Perhaps trouble going into the low mode?
 
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