MaxTuner

I am having trouble getting softer spring rates from JIC for the FLT-A2 coil-over system for my 2k maxima. They simply shipped me their standard rate of 9k/6k, and flat told me it was too dangerous to run anything softer???

I mean, i have done research before ordering and found that 5-6kg/mm is the ideal spring rate for street driven cars, why would they say it is too dangerous?

Please help and has anyone used softer spring rate for JIC before?
and I also ordered their helper springs to create dual spring rate and they said that it would be even worse with helper springs???WTF
I know a lot of KW, H&R coil-over systems, they all have dual springs rates for heavior european cars, why not on maximas?

Y2K2Driver

iTrader: (1)

Helper springs aren't going to work b/c the JICs work in way that prevents the spring from ever becoming loose in its perch by adjusting the lower spring perch up until the spring can not move up and down. Also, the weight over the front is such that the helper springs would just flatten out, trust me, I did the math on this one b/c I wanted to do the same thing. As for a lower spring rate, well JIC recommended 8kg to me, but I didn't think that would be enough, so got rid of them. If you run 5 or 6 kg springs, you're going to have to preload them a lot or the car will just rest on the bump stops. With the 9kg springs, the front only has a little over 1/2 inch of travel before the bump stop with no preload. When I pulled mine off I measured the dirt marks and what not to give me an idea of the conditions they were working under and they matched up with the math using weight and spring rate. All in all, while the JIC is a great suspension, if you ride on rough roads, the limited suspension travel will bite you, as it did me. If you have any questions about what I tried or learned trying, feel free to email me or PM.

Y2KevSE

iTrader: (13)

There is a ton of suspension travel on the front suspension. I have yet to bottom out on anything. How low did/do you have the car? I have 1 finger gap all around.

Also, did you lower the car via the strut body? Or did you just bring down the spring perch?

MaxTuner

So what is your spring rate for JIC? Can't I just adjust the damping with 5-6kg springs to not have that much of preload on them??? I never seen such of high spring rate used for maximas from coil-over system companies before, that is why I am very skeptical about running such high spring rate on a daily driven cars...as I am already suffering from 8/6 setup I have on my car right now.


I know different companies offer different valving on their coil-over, but I have seen ppl complained about the stiffness of ride and got rid of JIC, so I just don't want to end up the same way.

Dave B

Do the JICs use shortened struts because when I had Intrax springs, I only had ~.7" of upwards travel with the bumpstops uncut. The ride was pretty harsh and I didn't think I was riding on the bumpstops, but the truth was that I was on the bumpstops a majority of the time. I cut 70% of the bumpstop out and ride was a lot better. I added about .5" of travel with the cut stops. Seeing that the JICs sit much lower, I'd imagine that the .5" of travel Y2K2Driver noted is indeed correct, even with cut bumpstops.

It is entirely possible that the reason you don't thing you're bottoming out is because your car is literally riding on the stops nearly all the time. The stock suspension only has 3" of upwards wheel travel. Do the math and you'll see that chances are you are riding too low for the suspension to do it's job (ie soak up bumps without upsetting the chassis).


Dave

Y2K2Driver

iTrader: (1)

When I had them, I had them at about a one finger gap as well and yes I did adjust them via the strut body. However, the roads around me are rough and I know I was hitting the bump stops and often. There isn't as much travel as you would think with no preload which is recommended. With the 9k(507lb/in) springs and a loading of 1000lb per wheel, you take up 2 iches of travel just with the car resting. That leaves very little before the bump stop. You live in CA and I'm sure the roads are very nice and that is why your ride is nice, that is not the case here in the NE and especially not in PA with poorly patched concrete roadways.

Y2K2Driver

iTrader: (1)

I was the one who complained about the stiffness and got rid of them. I had the default 9/6 spring rates. I'm not really sure what you are asking with dampening and preload. The 6k springs will not be able to keep the car off the bump stops without preloading them. You would need more than 3 inches of travel to use the 6k springs to allow for approx. a 3 inch loss in travel with a static load and whatever else is going to be used for bumps. Again, I'd have to check my figures at home to see how much preload is required with that spring rate to give you some minimum travel for bumps. I think the reason the JICs go with such a high spring rate is that they do have a short body length and thus need to use a high spring rate to allow for the static loading and travel. Tien may very well use a longer strut body and thus has more travel. A lower spring rate means a larger static load travel loss, but since there is more travel, there is still enough left over for bumps. This really is a side effect of their implementations and their capabilities in terms of max drop. JIC alters ride height via strut body tuning while the Teins for the Max simply adjust the spring perch, thus the Teins can afford a longer strut body and all else leading up to the lower spring rate.

Y2KevSE

iTrader: (13)

Yes, JICs use shorted struts. You can actually slam the car and have the spring perches adjusted all the way up so there is preload on the springs. This is why I am VERY surprised when Y2K2Driver mentioned "the limited suspension travel will bite you".

Here is how much you can lower the car without adjusting the spring perch.



As you can see, that's a good 2" (at least) drop with FULL suspension travel in tact.

Nope... the ride over bumps and dips are as smooth as the stock suspension. Interested in JICs?

Here are more pics: http://www.boostedmaximas.com/y2kevs...-a2_coilovers/

Y2KevSE

iTrader: (13)

What was your stiffness setting? Mine are at a kidney-jarring 10/10... Turtle95Max has 2/2 but the road in his area is better.

Y2K2Driver

iTrader: (1)

I had them at 4/10. It wasn't the dampening that made them so stiff b/c I tried them at 0/0 and they were hard then too.

I think it is worth noting that the picture of the front struts doesn't reveal the fact that there are bump stops inside the unit. These take up travel (2"+ probably, but have to look at my numbers again to be sure) and the static load of the car takes up 2" w/no preload. In the end there really just isn't that much travel. It looks like a lot there, but it is deceptive. What I do know is that I was hitting the bump stops often and that made the ride very uncomfortable. You can adjust ride height quite a bit as you have shown though and I have not argued with that point, but w/o decent suspension travel before the bump stops, rough roads are going to be very painful. Given the linear nature of the springs, I don't understand why JIC doesn't just recommend preloading the springs as a way of increasing travel. It makes sense to me, though there is probably something internally that I'm not taking into account.

Y2KevSE

iTrader: (13)

Do you have documentation on the internal bump stops?

I'll check out how much suspension travel I have tonight.

Y2K2Driver

iTrader: (1)

No, but if you push down on the strut with no spring in it, you'll see that you won't be able to push it together all of the way. I have to imagine that an internal bump stop is doing this since that makes the most sense and occurs where one would expect a bump stop to be.

How much did you preload the spring?

MaxTuner

OKay, what about my questions? Why can't I have softer spring rates with helper springs??? JIC simply won't sell it to me for some reason, and why they mentioned dangerous for going 5-6kg/mm of spring rate?

BS or something about their coil-over design?

IceY2K1

iTrader: (3)

Y2K2Driver

iTrader: (1)

I answered your question. The helper springs are not strong enough to do anything useful, like create a progressive setup. They will simply be flattened. The other use for helper springs doesn't apply since the JIC setup adjusts ride height via strut body length. for coilovers that adjust ride height via the spring perch, then helper springs becomes useful b/c it is then very possible that during rebound, the strut expands more than the unloaded height of the spring and this will create some noise as the car falls back doen on to the spring. This is not an issue with the JICs. As for the 5/6k spring rate, the amount of travel available is not conducive to such a spring without preloading the spring. Without preloading the spring, the car will rest on the bump stop. This is obviosuly not what you want. It may be that JIC doesn't see the necessary preload as something that should be done. You need more info from them. As I stated, I'm not sure why they don't recommend preloading. To me, it seems like it should work, but I don't have all of the answers.

MaxTuner

They said by preloading the springs, you will raise the spring rate, and if you preloaded it too much, they want you to buy a different spring rate of springs!


bummer, i just don't see why 5-6kg/mm of spring rate won't work, as I am sure a lot of ppl who use FLT-A2 JIC suspension have changed their default spring rates that came with the system, in fact, some WRX owners recommanded changing them since the default rates are way too stiff for street use.

And 9kg/mm is crazy since our stock spring rate is like around 2-3kg/mm, factored in the reduced suspension travel, it still doesn't justify by using such of high spring rate. But of course, THIS system was originally designed for track use-----

I am just trying to modify the system into street friendly, and I think JIC kinda freaked out when they found out!

I have 8kg/mm and 6kg/mm on my current coil-over and i think it's not street friendly at all. I have talked to a lot of ppl and the ideal spring rate for street use is 5-6kg/mm..anything higher, you are going into Full Race setup!

MaxTuner

I found this article about recommended suspension setup:

""What kind of springs do I need?

Springs should first of all be the right length and diameter for the damper. (This is another reason why lowering springs do not work).

Other than length and diameter, spring rate is the main spring characteristic to look for. Anything below 30 N/mm or above 80 N/mm is wrong: below 30 N/mm, the car will roll like a boat, and above 80 N/mm, it will be so hard it will jump all over the place. A good road setup would feature 50 or 60 N/mm springs. This will give very good control and precise handling, but not send all the road irregularities into your spine.

Springs are often referred to in kg as well. When people mention 5 or 6 kg, that is 50 or 60 N/mm. (50 N/mm would be impossible to move and equate to replacing dampers with a metal bar)."""

See if anyone agrees to it?

carnal_c30

iTrader: (38)

the 8k/6k setup for the Maxima is really awesome, if you adjust it right it gives BETTER ride than stock and I have never ever been in a car with JICs that has bottomed out

I wouldnt slam slam it if you are that concerned, but even when I rode in Matthels car with the shock settings turned up and slammed his car never bottomed out

now my experiences in Brian cobymoby's car and Dennis Chinkzillas... the ride is better than stock very comfortable without floatiness

now my suspension set up... 10k/8k is rough its perfectly dampened but it is stiff and it will never bottom out I guarantee you!!! haha

the reason why you dont change the recommended spring rates is because JIC designs the shocks/struts to work with the exact spring rate of the car, if you soften the springs, you can really screw up the spring/strut combo and performance- trust me I know from experience!

if you arent happy with the way the JICs are then... feel free to sell them to me

happy adjusting!

Y2K2Driver

iTrader: (1)

Preloading the spring doesn't change the spring rate at all. Since these are linear springs, preloading only adjusts the starting force necessary to compress it some unit. This translates into the car dropping less from the static load of the car and thus more travel will result. The only question is, is there adequate room for the spring perch to move enough to preload the spring sufficiently to allow for a good ride? You have to remember that with a lower spring rate, the suspension moves more for any given size bump loading. As such, you need even more travel with the lower spring rate than you do with a higher spring rate, unless you don't mind hitting the bump stop.

I think part of the problem is that the max simply doesn't have a lot of travel to begin with. You would think so with its 4x4 look, but alas, it doesn't. I think Nissan engineers just slept through the suspension design on the Max b/c it is a mess, especially the rear.

Do you have the JICs now or no?

I wish someone told me this before I bought mine.

Confused

iTrader: (4)

have you checked out ground-control.com or other dealer of eibach ers springs? you can pic the rate/length in 2.25 or 2.5 diameters.

Y2KevSE

iTrader: (13)

Yes, I've pushed the front down... not all the way down. Too bad I don't remember how far it went down. I know the strut body was at the edge and the perch was all the way down.

Y2KevSE

iTrader: (13)

Are you taking into consideration that our cars weight 3200+ lbs, not 2800?

Your front springs will bind if they are too soft. You will DEFINITELY bind with 281 lb and 337 lb springs. GC's default spring rates are 450 front and 375 back.

Y2K2Driver

iTrader: (1)

My measurements reveal that in the front there is approx. 2.5" of travel before the bump stop is hit. Couple that with approx. 2" of lost travel due to the car's weight and you end up at approx. 0.5" of available travel. The look of the strut is decieving in this manner.

The dirt ring on the strut in the following picture is as far as you can go. As you can see, its not that far.

http://mywebpages.comcast.net/mpillmeier/DSC00186.JPG

MaxTuner

If that's the case, there are a lot of cars heavior than maximas and yet they have softer spring rate than 9/6 ??? Yes I am talking about the same series of JIC coil-over system..UNLESS they are valved differently for each car, then I am really surprised if JIC did that.?

MaxTuner

[QUOTE]Originally posted by Y2K2Driver
[B]

"""Preloading the spring doesn't change the spring rate at all. Since these are linear springs, preloading only adjusts the starting force rear."""







Well, that is what JIC SAID, I have no clue why by preloading the spring will increase the spring rate, want to have a lovely chat with Kevin at JIC???? Go ahead!

Y2K2Driver

iTrader: (1)

[QUOTE]Originally posted by MaxTuner
[B]I wasn't trying to be offensive, though I apologize if I came off that way. The confusion may ly in that preloading affects the starting force necessary to move the spring and thus could be said to affect the spring rate, though it isn't really. However, once that initial starting force is overcome, the additional force necessary to compress the spring is the spring rate. This is why one could preload a lower rated spring and enjoy the ride confort of that spring rate.

As for how other cars get away with lower spring rates, simple, they have more travel and thus can afford to lose more for the static loading. As someone mentioned, the Max only has apprx. 3" of travel stock in the front. That really isn't that much.

Chinkzilla

I'm so confused. Yeah they're stiff, I knew this going in, and so you should have as well. They're coilovers, what did you expect? The fact that they ride so well and quietly on smooth roads, better than stock even, is already incredibly impressive to me. If you gain in handling, you inevitably give something else up.

I left the preload/spring perch as it came, and I dropped the car a couple inches so that I have about an inch and 3/4's of thread between the two red rings. I have the fronts dampened at 4 and the rears at 5. I have never bottomed out, the springs are simply too stiff I assumed. And I have hit some pretty mean potholes.

Unfortunately however, I had to venture out of my nice flatly paved town last night, and had to deal with a bone jarring ride down a very badly paved 5 and 101 freeway. Nothing I couldn't deal with but unconfortable nonetheless.

Either way, I understand that this is what I have to deal with if I want the handling they provide. Overall I think the JIC's are the best ride in a coilover I've ever experienced.

Matt93SE

iTrader: (44)

let's put a few numbers to this...

how long are the stock springs? they're about two feet long, right? (a nice round number..)
I'll convert this back to lb/in units because that's what I deal with most of the time...

Factory springs are about 160lb/in on the front.
eibach are around 200lb/in.

A maxima weighs in around 3200 or so. let's say 70% of the weight is on the front.
3200 * 0.70 /2 = 1120lb per corner on the front.

the factory spring (on my 3rd gen anyway) is compressed about 4" before the strut mounts are bolted in. that's 640lb of preload on the spring. so with the strut completely extended, it's already got 640lb of load on it. (try compressing a factory spring/strut by hand while it's off the car. I'll bet you can't make it move much, if at all).
now, when you put it on the car, the front wheel is extended about 6" from the fender well, right?
when you drop the car off the jacks, it's around 2" from the fender now, right? that means the car has sucked up the preload on the spring and compressed it another 4". so you've got 8" of compression total. 8 * 160 = 1280 lb on each corner.

that's 160lb off from my guesstimates, but these are just ballparks so you'll understand the picture.....



Now let's look at your numbers.
you have 9/6 kg/mm springs on there now.

let's say the springs are 7" long. I believe that's what ground control uses for their kits.. at 450lb/in (8kg/mm).. the 7" long spring can only compress to about 3" before it coil binds (coils smash together).
1120lb / 450lb/in = 2.5" of compression.
the second you put the car on the ground, that 7" spring is only 4.5" long.
that means you have 1.5" of travel before the spring itself runs out of travel. imagine what happens when you stick a 1" long rubber bumpstop in there to keep the strut from bottoming out?
yup.. you've got about 1/2" of travel before you hit the bump stop.





now, go back to the numbers where you want 5 or 6 kg/mm springs?
in order to hold the car off the ground, you'll need a spring about 10" long.
the strut itself sucks up about 2" of the spring in mounting, then you'll compress it another 3.5" just from the weight of the car.
that's 5.5" of spring already used just to get the car to sit on the ground....


as you can see, springs that soft won't easily work on our cars. by the time you get one long enough to hold the car up, it's going to twist and bend and bind like someone trying to smash a slinky. It just won't work.


If you'd like to go even further, I can show you where my 450lb/in (8kg/mm) springs have been coil-binding on the front for the last two months because I was too lazy to put bump stops in there.
the enamel on the springs is completely worn off where the coils contact each other during compression.

Y2KevSE

iTrader: (13)

4" for mine... I'll post a picture in a few minutes.

Y2KevSE

iTrader: (13)

http://boostedmaximas.com/y2kevse/im...ilovers/12.jpg
http://boostedmaximas.com/y2kevse/im...ilovers/13.jpg

Probably more like 3.75" of travel because the 0" mark is a tad higher than the weld on the strut rod. The dirt mark is only about 1.25" so there's still 2.5" of travel left.

MaxTuner

One question, how did you deal with the ABS line? did you just zip tied them or what?

thx

Y2K2Driver

iTrader: (1)

Are you saying that the static load only results in 1.25" of lost travel? Did you preload the springs? The math and the real life measurements both match up in that 2" of travel will be lost due to the static load.

There may be 2.5" of travel, but about 2" of that is that bump stop travel, so I don't consider that available travel.

How far up is the second dirt ring?

I'm not complaining about them. Sure I did after I put them in, but that was a while ago. As far as I'm concerned, this was just an expensive learning experience. I knew I was making a tradeoff, I just didn't know how much I was trading in, and I don't see how I could have having never driven in a Max with a suspension with spring rates close to these coilovers. Ride quality is largely subjective and as such an opinion is only really as good as the expectations of that individual.

Y2KevSE

iTrader: (13)

Zip tie.


I don't know how much travel is lost, but I have 3.75" of travel with the car on the ground (springs compressed). Yes, I preloaded the springs a little per JIC dealer's advice.

I don't think the internal bump stop is 2". I had the car about .5" to .75" lower for a few days. Drove on the same roads I drive on now and did not bottom out.

I was referring to the second dirt ring (I can't see the first dirt ring because the CO is not off the car). The springs have only compressed 1.25" since the CO's were installed.




Are you sure your struts weren't blown? You seem to be the only person who has bottomed out.

Y2K2Driver

iTrader: (1)

I don't think the ride height of the car is going to affect whether or not you are going to hit the bump stops as the spring is left untouched during that change.

I'm pretty sure the struts were fine as I pushed down on them after I had uninstalled them and they had a lot of resistance. Also, the adjustment valve worked.

I'm somewhat confused about your car only losing 1.25" in static drop. Are you using 9k springs? If so, 9k = 506lb/in. Approx. 1000lb over each wheel means a 2" static drop assuming no preload. The math here verifies what I was seeing on my car. How much did you preload the spring?

It is very possible that if you preloaded the springs a bit and have very nice roads around you, that you would never hit the bump stops. Like I have said, the roads around me are horrible. The only way to tell is if you could find the 1st dirt ring(top most since when I said second before this is the one I meant) which would indicate the maximum deflection the spring has undergone during driving. On my car, that dirt ring was above the point I believe the bump stops start, thus leading me to believe that I was hitting them.

All of this is rather academic anyhow. To really answer the question, you need to remove the strut. To answer the original question, I believe that you could get away with a 6k spring if you could get one that is longer than that which JIC offers as standard and then preload it sufficiently. A 6k spring 1" longer than standard preloaded 1.5" (approx. 500lb starting force) would allow for approx. 1" of travel before the bump stop using my measurements.

Y2KevSE

iTrader: (13)

Ride height will affect whether you are going to hit the bump stops if you lowered the car via the spring perch and not the strut body.


How fast did they struts rebound?


I'm using default spring rates. What do you mean by static drop? Are you talking about how much the spring is compressed after the car is dropped? If so, it's not 1.25". Please note that I did not take off the struts to see both dirt rings. I can only see one dirt ring because the struts are on the car. The top dirt ring is 1.25" from the lower dirt ring so that is the maximum amount the strut traveled.

The springs were preloaded about 1 full turn after reaching the top.


I don't have nice roads around me. There's this one dip that bottoms out the GC and Koni setup while driving 50+ mph. I can go over this dip with the JIC at 80+ mph with no problems. Smooth as butter... Turtle95Max has gone over this dip with 4 people in the car... no problems either.


How far up is your spring perch? Like these?
http://www.boostedmaximas.com/y2kevs...ilovers/07.jpg

Y2KevSE

iTrader: (13)

6k springs that are 1" longer will not work. Check out Matt93SE's explanation.

IceY2K1

iTrader: (3)

Easy solution....put a zip tie on that bish and go find a speed bump.

I'm SERIOUSLY interested in this "debate".

Y2K2Driver

iTrader: (1)

But we all know that the JICs aren't adjusted that way.

The rebounded slowly and became even slower as the dampening was increased.

When I say static drop, I mean the amount that the spring compresses with only the car's weight acting on it. I'm not sure what to make of the differences between your setup and what I had. I'm obviously not in a position to contest since I don't even have mine anymore and therefore can't check them. All I comment on is what I experienced during my trial with the JICs and measured during that time.

Well, I guess nice roads is relative. To elabortate my situation, the roads are concrete with many sections patched with asphalt and the speed driven on them is about 80+ mph. There are also numerous sections that cross other roads, train tracks, etc., these sections are often very poorly matched up and thus a large bump exists there. My problem was never with gradual dips and the what not, but rather with quick bumps that just jarred the car. I guess the 9k springs are going to be rough in that situation no matter what. Since this is my daily driver, I couldn't have that.

I didn't think of that, though I still believe that there is a length that would work, the only questions then are how long does it need to be to not bind and will you be able to get everything onto the strut successfully so that it doesn't interfere with the body length adjustment.

Y2KevSE

iTrader: (13)

They can be, so when someone bottoms out with this setup, we have to ask if he/she adjusted via the perch. You obviously know what you're doing so I know you didn't lower via the perch.


Sounds normal.


I don't know the length of the strut rod when it is uncompressed, but if someone knows, he can subtract 3.75" from that to get the static load.


I also have railroad tracks, patched asphault, cracked roads, etc. Anything you have in NE, I have driven over with the JICs here. I can easily cruise over these road imperfections faster than I could have with GC/Koni. With GC/Koni, I did sometimes bottom out.

My rough may not be your rough, relatively speaking. I guess we won't know.


Hmmmm... just though about this. Since there is still about 1" to 1.5" with 0 preload on the spring, longer springs (softer spring rate) will do no good unless you preload them like crazy.

Y2K2Driver

iTrader: (1)

That is exactly what I have been saying is an option for those who want to try a softer spring rate.