Help! iON HD mystery

I recently purchased a set of iON HD springs for my 05 GT Limited MT wagon. The goal was to provide rear suspension support for trailering my boat when the wagon is loaded with my family, bikes on the roof, and stuff in the cargo area. After much research and a try at using Megan Racing coilovers at their maximum height (good load carrying ability, good handling on smooth roads, unable to handle rough New England road conditions, 1" drop) I settled on the iON HD rear springs as the best available bet to handle the rear loads while maintaining something approaching stock ride height and attitude. The information from iON and posts here indicated that rear non-loaded ride height would increase 1/2 to 1". A little high when unloaded, a little low when fully loaded; overall, the best available compromise.

 

I received the springs last week from iON Performance. Due to a series of events, I ended up paying new prices for a set of used springs. I finished the install last night, went for a three mile spin to settle things in, and went out this morning to see how things looked. Much to my surprise, the rear had been dropped! WTH?

 

The following is the before stock ride height, measured with 35 psi in the tires, and a half tank of gas, and measured at the center line of the wheels from the ground to the edge of the fender cut-out:

 

front right: 26 3/4"

front left: 26 1/4"

rear right: 26 3/4"

rear left: 26 1/2"

 

These are the rear measurements after the installation of the iON HD's, everything else is the same:

 

rear right: 25 9/16", a drop of 1 3/16"

rear left: 25 5/8", a drop of 7/8"

 

In other words, the rear is on average almost 2" lower than where I was told it would be.

 

Attached is the picture of the iOH HD's with one of the stock rear springs.

 

What's going on? I'm a bit old (56) to be constantly swapping out springs in my driveway using a jack and stands.

 

Thanks for any wisdom.

 

rayu

by the looks of the springs side by side it's pretty obvious the Ions are appox. 2" shorter which would account for the 2" drop. not sure what your asking. bosco

I have almost gone through every iON combo available.

 

What springs do you have in the front?

 

The HD rears on my SEDAN were about OEM ride height.

 

 

 

If you had iON front springs on (which I don't think you have) the car would be fairly level, maybe even a bit raked. At least the rear is more level from side to side.

Front springs and struts are stock. Rear struts are stock. Only change was swapping rear stock springs for iON HD springs.

 

On bosco's point: Unloaded spring length does not, in and of itself, determine loaded spring length. Spring rate combined with length and load will determine loaded spring length.

Front springs and struts are stock. Rear struts are stock. Only change was swapping rear stock springs for iON HD springs.

 

On bosco's point: Unloaded spring length does not, in and of itself, determine loaded spring length. Spring rate combined with length and load will determine loaded spring length.

 

 

On Bosco's point: Rayu is right.

 

You should really have iON front springs as well, then I think your car would be fairly level.

 

On another note, your initial measurements seem a little off. My car was lower in the rear then front with OEM stuff. How even was the pavement you were on for initial measurements

 

Sorry to say it but I think the HD rears sound like they are doing what they should, but paired with OEM front springs won't really work.

 

You could always do an extra spring seat in the rear.

 

At least these spring will not sag near as much under heavy load.

rayu - You've just answered one of the questions that we had needed to know. the HD's are intended for use with our Sport Specs in the front; as per PM there's another way to attack this if you're looking to use stock springs in the front. please check your PM's.

I'd think you'd want to do all four corners. Is it even safe to swap just rears? Aren't HD's like 30% firmer than stock in the rear?

I'd think you'd want to do all four corners. Is it even safe to swap just rears? Aren't HD's like 30% firmer than stock in the rear?

 

Probably more like 40% stiffer.

Probably more like 40% stiffer.

 

gezzus...with stock front springs.....

The mystery deepens.

 

This all started after I bought the wagon to replace my Passat wagon and I wanted to replicate the sweet set-up I had; rear Nivomat self-leveling shocks that kept the wagon level independent of how much trailer tongue load there was or how much load was in or on the car.

 

Nothing equivalent is available for the LGT. Given the load and road conditions I encounter all the time, I did not want to lower the ride height. In direct response to my question of ride height vs. stock, Jack at iON told me that the unloaded height would be slightly higher at the rear than stock. In addition, Jack at iON said the intent of the iON HD's was to provide rear stiffness for tradesmen and the like who carry tools or other heavy items in the rear. Never was it stated that the iON HD's were lowering springs. I also was told that the Megan Racing coilovers could be set to stock height. That proved not to be true and is one reason they had to come off.

 

Now the story is that the iON HD's are lowering springs and will only achieve a level stance if paired with iON Sport springs up front. I am willing to consider matching front springs but I do want a lowered vehicle with its diminished ground clearance and reduced suspension travel.

 

It is frustrating that it is so hard to get correct information. I still don't know what the actual spring rate is on the iON HD's. The lack of correct information translates into wasted time and money.

iON Sport Spec rears are 6.7kg/mm (382lbs./in.)

 

I would guess HD's would be 7+kg/mm.

 

I think your best bet would be to get a set of JDM GT Bilsteins and OEM JDM GT springs. That will firm things up really nice and give you the stock-like ride hieght. PM unclemat...maybe he has some coming in from Japan.

Thanks for the info. That Bilstein set-up would be nice but sounds pricey. I'll check with unclemat.

 

I think we have solved the mystery. Jack at iON has confirmed that they changed the spec of this years LGT iON HD rears and shortened them. They now are basically a stiffer sport spec. Would have been nice to tell me. It appears that the iON rear spring I want is, this year, designated as the OBXT Sport Spec. If I understand right the lowered OBXT spring = last years's LGT HD spring with a result of stock or a tad higher rear ride height under empty load. Hey, what else do I have to do with my time than swap springs?

 

Last year BoostJunkie warned me that in certain situations having the stiffer rear springs with the stock fronts could result in some tricky handling. I'm less concerned with the front/rear imbalance than with the stock dampers having to handle the stiffer springs. I think the worst case will be when lightly loaded when the stiffer spring wants to act like an empty pick-up truck. On the other hand, the stiffer rears will help flatten cornering.

 

 

iON Sport Spec rears are 6.7kg/mm (382lbs./in.)

 

I would guess HD's would be 7+kg/mm.

 

I think your best bet would be to get a set of JDM GT Bilsteins and OEM JDM GT springs. That will firm things up really nice and give you the stock-like ride hieght. PM unclemat...maybe he has some coming in from Japan.

Don't worry too much about stiffer rear springs upsetting the handling - we all upgrade our RSBs to get a little more tail action

On bosco's point: Unloaded spring length does not, in and of itself, determine loaded spring length. Spring rate combined with length and load will determine loaded spring length.

 

no kidding i guess you learn something new everyday your missing the point and the point is lenght for lenght those stock springs which are appox. two inches longer are still going to sit higher than the stiffer springs. the LGT spring rate is not that much less that it would affect height as much as you think. bosco

My sense in looking at the springs side by side on the bench was exactly yours; this is going lower. But since I didn't actually know the spring rate on the iON HD's and I don't really know the load each spring sees from the weight of the car and the suspension geometry and I had been told that they would keep the stock ride height, I went ahead and installed them. I'm waiting to hear from iON on when they can get me the correct springs.

 

no kidding i guess you learn something new everyday your missing the point and the point is lenght for lenght those stock springs which are appox. two inches longer are still going to sit higher than the stiffer springs. the LGT spring rate is not that much less that it would affect height as much as you think. bosco

This past weekend I hooked up the boat to head up to NH for some boating on a beautiful weekend. AARGH! The rear of my wagon sagged to lower than it did with the stock springs. Check out the attached pictures. I drove around the block and decided it was not safe for a longer tow; rear too low with too little travel, front too high. Based on the sag (and this was with just me in the wagon), I believe that these are not HD springs at all, just regular iON Sports. They have no decipherable markings; so who knows? They certainly are not nearly as stiff as the Megan Racing coilovers I had.

that is definitely major saggage why did you get rid of the coilovers and what wheels are those? bosco

rayu - Those you have are indeed the HD's, as the regular sport specs would be lower. Please check your Pm's.

Bosco,

 

Interestingly, the towing with the Megan Racing coilovers was excellent; just the right amount of stiffness in the back end and a nice balanced stance. They came off because they simply did not have the travel or valving, especially for the fronts, to handle the crappy New England roads. The front would frequently crash to a fully compressed state (coil on coil) with an unnerving noise. In addition, I really did not want or need the 1" lowering which was the highest I could set them to.

 

The wheels are forged polished alloy Centerline Storms, 7x17, with Kumho 225/45ZR17 ECSTA SPT tires. I believe you are the only other member who had these wheels. The offset puts them about as wide track as one can go without fender interference. I like them because they are light, classically styled, American made, a good buy, and I am a fan of the polished alloy look.

 

rayu

Bosco,

 

Interestingly, the towing with the Megan Racing coilovers was excellent; just the right amount of stiffness in the back end and a nice balanced stance. They came off because they simply did not have the travel or valving, especially for the fronts, to handle the crappy New England roads. The front would frequently crash to a fully compressed state (coil on coil) with an unnerving noise. In addition, I really did not want or need the 1" lowering which was the highest I could set them to.

 

The wheels are forged polished alloy Centerline Storms, 7x17, with Kumho 225/45ZR17 ECSTA SPT tires. I believe you are the only other member who had these wheels. The offset puts them about as wide track as one can go without fender interference. I like them because they are light, classically styled, American made, a good buy, and I am a fan of the polished alloy look.

 

rayu

 

if the coilovers had the right spring rate in the rear you would think you could find springs close to that for the rear. your car looks good i thought those wheels looked familar. yes the Centerlines are very nice for the price being rotary forged, made in the USA and super light they just need more offset. btw i still have a set chromed like new if you know anyone interrested bosco