So after a few hours of reading through old threads on using 80 series coil springs in the rear, I am now totally lost. I have an 03LX470 with the AHC. I see some guys are using the standard NON AHC springs to get lift while others are using the 80 series springs to get lift. So I THINK I understand the info as follows. The AHC rear springs are the thinnest/shortest. The standard 100 series springs are thicker/stiffer which will give a little lift IF the rear sensor is adjusted on the AHC OR will give more support to the AHC system if the sensor is NOT moved, correct? The 80 series springs are the tallest of the 3 and will give a LOT of support to the AHC OR can give even more lift then the standard 100 series springs, correct? Now we get to spring difference. One thread says there is a left and right side to the rear spring for the 100 series. Another thread states the springs are identical on the left and right. I can guarantee the 80 series has a left and right side but I'm not sure the 100 series does. A few threads say the 100 series has a left and right side (left being taller) but the online parts catalogue I looked at shows both springs with the same part number. A dude from down under said that only the LHD 100's got different springs since the driver, gas tank, and a few other things are all on one side. So IF I use 80 series springs then I need two left or two rights, correct? If I use a NON AHC 100 series springs then with RHD (USA spec) then both springs will work and it doesn't matter which one goes on which side, correct? I currently have some 30mm spacers for the rear and some 80 series springs left behind from my last 80, but now I think I need to find one more of the left or right spring or just find some used standard 100 series springs. Sorry for all the questions, but there are a TON of contradictory threads on this topic. I will be starting the build soon and I want to make sure I have the correct parts before I tear into it. I'm thinking I want 30mm spacers for the lift (adjusting the rear AHC sensor to account for the space) and then standard 100 series springs to lighten the load on the AHC. Maybe that is a horrible idea but that is why I started the thread. If it is a bad idea then please clue me in to why.
confused about rear coil springs
- Thread starter bhicks
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I still have the LC100 non-AHC in my garage, ready to put in. When I checked them they are nearly identical, although 1 is only 2mm shorter.
Not sure if that is the difference they are talking about.
Not sure if that is the difference they are talking about.
- Thread starter
- #4
I am definitely interested but shipping them across the county will probably be a deal killer. I'm sure there is some socal guys with some extra 80 series or 100 series stock springs laying around. I already have a set of 80 series springs. I just need one more so I can match up the two left or two right springs.
- Thread starter
- #5
That difference is probably the reason for the different part numbers for the Aussie 100. The US 100 seems to have matching rear springs. I just need to track down some local non AHC springs or another set of 80 series springs. Hopefully someone will verify if the 80 series springs are taller then the standard 100 series springs. That fact was implied in a few threads but never verified.
Pretty dang sure the rear coils on both 80s and 100s are symmetric. I'm not the authority on the topic, but I've done 4 or 5 sets of rear coils between my old 80 and my LX, and I don't recall distinguishing the rears left from right. I do think the front coils on 80s are asymmetric due to a higher spring perch on the passenger side. Maybe this is the source of confusion (?)
Of course, everything I just wrote could be completely wrong.
Of course, everything I just wrote could be completely wrong.
- Thread starter
- #7
I know for certainty the rear springs on the 80's are different. When I installed my OME Heavies lift i put the springs in reverse and I had a horrible lean. I swapped the rear springs and it sat nice and level. There is also a few threads that mention needing two matching lefts or two matching rights. My bigger question is which is a taller/more lift spring. The 80 series coils or the 100 series NON AHC coils? I can get the 80 series coils for free since i already have one set and a buddy has another set just taking up space in his garage. I'm just afriad the 80's coils WITH 30mm spacers and an AHC sensor adjust will get me too tall in the back. I'm already 1.5" taller in the back with the factory rake. I would like to get the rear maybe .5-.75 talller in the back/less rake. That means however tall I go in the back I need to go about .75" taller in the front. Ideally 1.5" of lift out back and 2.25" up front would be perfect. 30mm spacers give you 1.1" so I was hopeful the other .4" would come from either the 100 series non AHC springs or the 80 series springs (and the proper adjustment on the AHC). The front will just get an AHC adjustment by cutting the bar and lowering the sensor as far as it will go and then adjusting the torsion bars using the TechStream (just arrived) and getting it back within spec. Not sure if any of this is going to work. I am trusting all the folks on here.
im going to change out my suspension in a month or so if you can wait that long i let you know
I suspect you will be happier ultimately if you determine your desired built weight/lift and install an aftermarket suspension actually designed for your profile. I say this based on your post in the $870 brake thread, if you're not ok maintaining AHC now you'll have a lot of trouble dialing in and rebalancing pressures in your modified system to get acceptable damping performance.
- Thread starter
- #10
I'm not even sure what "maintaining the AHC" means". I went through my owners manual and no where in there does it suggest a flush. The Lexus dealership even stated that it is rarely done. He stated they have seen LX470s with over 200k and the original fluid with zero issue. I'm at 80k so I'm not going to worry about it. In regards to build weight. It will be very light. I will be building a custom tube bumper out back 60-70lbs. with no tire swing. The BenC bumper up front 85lbs. and White knuckle sliders. The factory spare, hitch, and running boards will all go. The 3rd row will also go. That will leave the rear a tad lighter then stock and the front about 60lbs. heavier than stock. The AHC should have no issue handling the extra weight up front. My guess is that the standard 100 series springs with 30mm spacers and an adjustment on the AHC sensor will give me the perfect set up for the rear. The rear should have a decreased load on the AHC since I will be putting more of the vehicles weight on the springs. It's the front I'm a little worried about. I will be using the AHC and torsion bars to bring up the front. My fear is that it is going to ride very rough. Maybe the OME torsion bars will help smooth it out? I will use JUST the AHC and factory torsion bars first with the help of my new Tech Stream and see how it rides. If it sucks, then I will adjust accordingly.
- Thread starter
- #11
where are you located?
From my reading here, mixing non-AHC springs with the AHC system is troublesome, definitely not simple. I get the impression that it doesn't work so well.
For what it's worth, I think the OME torsion bars, medium coils, and shocks ride just fine. When I pulled off my AHC and replaced with the OME medium stuff, I thought it rode very much like the "sport" AHC setting. It's also stuff you never have to worry about. Strong and simple, as opposed to weak and complicated AHC.
For what it's worth, I think the OME torsion bars, medium coils, and shocks ride just fine. When I pulled off my AHC and replaced with the OME medium stuff, I thought it rode very much like the "sport" AHC setting. It's also stuff you never have to worry about. Strong and simple, as opposed to weak and complicated AHC.
Dealer is wrong. AHC fluid should be replaced every 60k under normal conditions.
https://secure.drivers.lexus.com/lexusdrivers/info/my-lexus/service/maintenance-schedule.do
BTW I'm running non-AHC springs with AHC. You can read about the details in my build thread.
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- #14
What are your thoughts on the non-AHC springs with the AHC system? The pile of threads out there are completely contradictory. Did you add any spacers with the springs? Did you adjust the AHC sensor? If so, how much? did you try to gain any lift using the non-AHC springs? Ride quality?
downtown la
- Thread starter
- #16
Perfect. Shoot me a PM/start a conversation when you have them off and we will figure it all out. Now I need to find the factory front NON-AHC Torsion Bars. Once I have the factory non-AHC TB's, and the factory rear non-AHC springs then I no longer need to worry if the AHC fails. I don't want to deal with the headache of maintenance on that system.
- Thread starter
- #17
So it looks like I may be able to get the springs from LowbudgetTLC100 and I now have two sets of rear 80s springs in case there is a difference from left to right. I have 2 left and 2 right. I still need some more info on the 80 series springs before I move forward on the suspension. Is there a difference between the 80 series springs and the 100 series springs in relation to height? Are the 80 series springs taller and if so, by how much? Do they have a higher/stiffer spring rate or the same or less? I just need to know what springs I should be putting in my 100. I have 30mm spacers ready to go in but not even sure I will need them with 80 series springs if I only want about 1.5" of lift out back. I want to lift with springs and spacers and not put a load on the AHC. I hope to keep it and keep the pressure at stock with the right amount of spring and spacer lift out back and the use of the techstream. Hopefully the Tbars will be enough (if I can find a pair of Non-AHC bars) to lift the front up enough to take the load off the AHC as well. I want to make sure that if my AHC fails my rigs weight is on the springs and bars and wont just sink down to the L setting.
hoser
SILVER Star
-The 100 series springs have a small height difference DS to PS. The 80 springs have a larger difference.
-I suspect 100 series springs have a higher rate than 80 series springs but have not calculated it.
-The jump in spring rate between non-AHC and 80 series is quite bit.
-If you have no extra weight or less weight than stock, I would just try adding the 30mm spacers (and adjust rear AHC height to get acceptable AHC pressure). Next choice would be two shorter 80 springs
-Don't strive for lift but rather ride height. The front end likes a "center-hub to fender" measurement of 21" or less with AHC shocks. Rear should be 1" more.
-The AHC front t-bars will be best for the weight you stated.
-I recommend the rear AHC shock extension brackets along with 1.5" lowered bump stops.
-I also recommend inspecting/changing the AHC shock bushings at 100k as they wear out faster than traditional shocks as they carry weight.
-I suspect 100 series springs have a higher rate than 80 series springs but have not calculated it.
-The jump in spring rate between non-AHC and 80 series is quite bit.
-If you have no extra weight or less weight than stock, I would just try adding the 30mm spacers (and adjust rear AHC height to get acceptable AHC pressure). Next choice would be two shorter 80 springs
-Don't strive for lift but rather ride height. The front end likes a "center-hub to fender" measurement of 21" or less with AHC shocks. Rear should be 1" more.
-The AHC front t-bars will be best for the weight you stated.
-I recommend the rear AHC shock extension brackets along with 1.5" lowered bump stops.
-I also recommend inspecting/changing the AHC shock bushings at 100k as they wear out faster than traditional shocks as they carry weight.
- Thread starter
- #19
That answer was fantastic. I will go with the 30mm spacers and AHC adjust only for the rear and see how it rides. I deally I would like the standard "N" height to be the current "H" but without making the AHC do the heavy lifting. If I feel I need a firmer or taller ride then I will toss in the short side 80 springs and go from there. I think I will still search for the standard non AHC tbars since I eventually plan to run a winch bumper and winch up front and I don't want the added stress all going to the AHC system. If I don't like the ride I will keep the AHC tbars as a back up in case I want to put them back in. None of these options cost much if any money. It's more just the time in gettting the suspension stable but not too firm and the correct length bumpstops to prevent rubbing on the trail. I should have this all dialed in my the end of this upcoming summer. Once I add the armor I will probably need to tweak the suspension some more.
hoser
SILVER Star
There are 50mm spacers available... which are probably better suited for you. But I would only use them in conjunction with the shock extension brackets/lowered bumpstops... w/o the bracket, I'd have concern about over-compressing the springs. If you build the 100 lightweight but find yourself packing it to the gills, then the AHC rear springs will not work for you.
