AHC. Level with me.

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JessPurviance

JessPurviance

10 Year
Joined
Jan 21, 2016
Threads
8
Messages
81
Location
Overland Park, KS
Website
pilgrimanimation.com
I've had the LC for a few months and have been baselining it. I noticed the left front was about 1/2" lower than the right (or was the right a 1/2" higher than the left?) measuring from the center of the hub to the wheelwell. I cranked on the left TB and it leveled out, but I thought the AHC was self-leveling. Why wasn't it self-leveling in the first place?
 
The AHC is self leveling.

Have you driven around since adjusting the torsion bar? It will likely go back to where it was as soon as the system recognizes the change. To properly adjust height differences, you have to adjust the AHC sensors (2 in front, 1 in back). Likely, your left front sensor is off and thats why its self leveling to a non-level stance.

You should only really adjust the torsion bars after adjusting the sensors. And you adjust the bars in order to get your shock pressures back into spec.
 
Hydraulic active self leveling is front to rear, not side to side. TBs adjust left to right cross level mechanically (as you found out) and front neutral hydraulic pressure.
Edit. For a 1/2 in correction I'd be inclined to split the difference and raise the low side 1/4 and lower the high side 1/4 then rebalance pressures (and the height sensors if necessary) equally. This approach is less likely to result in winding up one torsion bar significantly more than the other, thereby giving you an uneven damping response between left and right fronts.
 
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I hope you have a windows XP 32 bit computer! I only have an older windows 7 64 bit and it took me a good 5 hours to get techstream to work on it. It was very gratifying having it finally connect though.
 
PADDO said:
Hydraulic active self leveling is front to rear, not side to side. TBs adjust left to right cross level mechanically (as you found out) and front neutral hydraulic pressure.
Edit. For a 1/2 in correction I'd be inclined to split the difference and raise the low side 1/4 and lower the high side 1/4 then rebalance pressures (and the height sensors if necessary) equally. This approach is less likely to result in winding up one torsion bar significantly more than the other, thereby giving you an uneven damping response between left and right fronts.
Click to expand...

Good idea. The left front seemed a bit soft to begin with. Sometimes it would kinda dive when braking and turning. It feels pretty even now. Once I get techstream hooked up and read the pressures, should I re-adjust the TB?
 
Yes once you get visibility of your pressures it is very very likely you'll need to adjust TBs again, and add coil spacers/new coils for the rear. Standard approach is: get your cross level corrected; measure then adjust, if necessary, front & rear heights and then get your front and rear pressures dialed in.
 
I thought they all leaned to the driver's side a little when the gas tank is full. I know mine does. I thought I was normal, but I do not have AHC.
 
PADDO said:
Yes once you get visibility of your pressures it is very very likely you'll need to adjust TBs again, and add coil spacers/new coils for the rear. Standard approach is: get your cross level corrected; measure then adjust, if necessary, front & rear heights and then get your front and rear pressures dialed in.
Click to expand...

I got my cable and techstream this weekend and was able to read my AHC pressures. Front was 6.5, Rear 7.1. So it looks like I will need to back off the front TBs a bit to get it into spec. Also, since my original adjustment to the front left TB, the right side, both front and rear is now slightly lower. So I will back off the left TB about twice as much as the right. I'll post again on how that goes. :)

On a side note, the Techstream software I bought works on my Win10 64 bit machine. The seller included some great instructions and several files to make it work. I plugged it in and it connected the first time. I'd reccomend this ebay seller if you are looking for TIS Techstream: 2015 Original Mini VCI Diagnostic Cable for Toyota Lexus TIS Techstream fw 2.0.4
 
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