Q spring rates?

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

Anyone know the Q spring rates? There are a few options for you pre97 Q owners for struts but us 97+ guys are kinda stuck:).Im working with a guy on possibly getting a Koni setup done on the factory struts so if anyone has spring rate info that would help decide on the insert we use.

Thanks!

Terry97Q92 Classic SE-R W/Boost

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

The 90-93 had 146# front ......the SAI is 13 degrees and 123# rear per manual.

Spring rate vs wheel spring rate [corrected for spring angle and attachement point offset] needs to be measured almost impossible to calculate within say 5%.

The manual no longer provides adequate info to calculate 97 and later but they [especially the rear] can't be much difference since this is primarily a function of weight on the spring and how much shock travel is available.

Lowering a Macpearson strut front is tricky because of very minor camber curve available.

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

Thanks for the info, Im not looking to change anything as far as lowering. Basically were looking to see if we can gut the stuck strut housing and use a high quality Koni insert.

Terry

Post by **reggiegsd** » Thu Jan 23, 2003 10:07 am

I know Koni will build an insert for any application. The last time I checked with them it was about $600 per shock and you had to give them the valving specks. Plus, these were hydraulic and not gas shocks.

I read a few months ago that Tokico was opening a rebuild facility in California but haven't seen anything on it recently. Wouldn't a set of Tokico Illumunas for the Q be great.

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

Well i can tell you that it wont be anywhere near $600 a cornor for this setup...It probably wont be much more then the OEM struts...Of course we wont know exact pricing til i get him all the specs.

Terry

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

Remember the shock compression rate is designed by weight and spring stiffness...........but rebound is where you want variablility as this is where the wear occurs first and different tires/sway bars need to be dialed in with adjustable rebound [expansion].

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

OK thanks...There maybe a few different options as far as inserts go...I just need to get the strut specs to the guy.

Terry

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

Q45tech wrote:The 90-93 had 146# front ......the SAI is 13 degrees and 123# rear per manual.

Spring rate vs wheel spring rate [corrected for spring angle and attachement point offset] needs to be measured almost impossible to calculate within say 5%.

The manual no longer provides adequate info to calculate 97 and later but they [especially the rear] can't be much difference since this is primarily a function of weight on the spring and how much shock travel is available.

Lowering a Macpearson strut front is tricky because of very minor camber curve available.

Need a clarifaction on the spring rates...Is that lb/in or kg/cm? Im refering all this info to the suspension guy, want to be sure i give him the correct info...Hey thanks a bunch for the help on this guys!

Terry

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

pounds per inch but again not sure if they are saying wheel rate or the springs alone ! Normally one would send a front and rear spring and let the engineers evaluiate the pitch to make sure it is linear.

On luxury cars there is so much rubber in seats and multiple bump stops AND the GAS charge must be calculated in shock as the Tokico do provide a little expansion lift which adds to the springs.

Normally one would install the whole assembly on a spring rate tester and cycle the system at varing stroke lengths and rates to get curves at different temperatures.

All in all it is complicated and the factory gets it just right for new components then the after market just adds some fixed percentage.........in the case of Eibachs they made the rear progressive in spring rate with a linear front.

Even a 10% error can lead to pitching of car body since the the tuning speed over interstate seams will vary........what speed are you asking for the system to be tuned to?http://www.efunda.com/DesignSt...#calch ... pensn.html

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

The surest way to end up unhappy is not to completely understand every aspect of a spring redesign so you know what to expect! Relying on others to 2nd guess what they think you want is iffy!

Lowering a car can make a 2% improvement in handling at most yet the ride can get 20-50% rougher and annoying not sure most would find the trade off worth it in long run !

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

Dennis - I have an opportunity to purchase some new Eibach's for my 95Qt pretty cheaply. They reportedly reduce ride height 1"F/.08" R. Is this what you have on your Q?

I had spoken with Fred about his Eibachs but he indicates they dropped the car more than that (approx 2").

I know it's hard to estimate, but given my setup (245/50/16's, Tokico blues, 20mm rear bar, all new suspension bits) do you think the ride will be too harsh? I'm concerned the Blues will increase the height somewhat (as you mentioned).

Anyone else care to chime in as well?

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

I use the 1/0.8 Eibachs..............you must understand that the rears are progressive in that they start out at stock rate then get firmer and firmer as they compress in the next 3.5". Shocks don't work this way so the blue feel initially harsh, just right, then progressively under controlling.

Every Q wheel well opening is different and they vary from side to side because the springs/mounts change a little with age.

Eibachs may rattle in rebound unless spiral dampening material is used and tie downs to perches to hold springs in place when body rises to limits.

All in all considering that springs have very little to do with handling and only improve things by lowering the center of gravity/ by the track width...............1" is about 2% less weight shift so the tire sees about 8 pounds less than the 400 pound nominal........but since static tire loading is 1200 pounds.........1600 or 1592 is not measurably different something like a 1/2%. Much of the improvement in handling comes from the EXTRA negative 0.8 degrees camber that the lowering springs induce.

Lighter cars with less static weight on tires seem to get more improvement from lowering and cars with narrower track width gain more from lowering.FWD rice rockets tend to be lowered too much for looks and typically handle worse than stock........but they don't care.

My Q is at -1.5 degrees CAMBER both fronts and both rears [needed a new rear subframe to get it less than - 2.0 degrees on rears after lowering.

Personally I would stay with stock springs and keep the extra 1" of suspension movement as the +- 3.5" stock is pretty tight as is.

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

If you fill the wheel wells up with 255/50/16 like they are supposed to be [the same diameter as 215/65/15] it will look better and you will gain much more from the 100 pound increase in load rating................instead of the 1/2% from springs you will get 3.125% improvement from tires [improvements is usually half of the load rating increase [100/1620=0.0617/2=0.0308].

The slip angle decreases as the real load vs max load ratio improves.

The following should make it clear:http://www.nupes.cefetpr.br/Pr...#3096h ... Spring.pdf

Post by **maxnix** » Thu Jan 23, 2003 10:07 am

Q45tech wrote:If you fill the wheel wells up with 255/50/16 like they are supposed to be [the same diameter as 215/65/15] it will look better and you will gain much more from the 100 pound increase in load rating................instead of the 1/2% from springs you will get 3.125% improvement from tires [improvements is usually half of the load rating increase [100/1620=0.0617/2=0.0308].

The slip angle decreases as the real load vs max load ratio improves.

The following should make it clear:http://www.nupes.cefetpr.br/Pr...#3096h ... Spring.pdf

And this should be an amen to the lowering questions for a Q45,

Dennis has stated this at least three different ways in the past. These two posts should be part of 1st Generation (G50) FAQ, under "Lowering Springs."

Dennis' answer for those who want their cars to "look cool" may be too subtle, though.

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

I bought the Eibachs [at a discount] before I fully understood the ramifications of lowering the Q. I lowered the rear first alone then a year later did the fronts.I was ignorant of much of the things we now take for granted -- 6 years ago.First used Tokico blue shocks in 1994 replacing oem at 50k now on my 4th set, so I have some experience with them! Same 4 sets of mixed front shocks.Same with rear sway bars have had none, 15.9, 24, and now 20 mm. 29 and 28mm current front bar.......the full gamut of adjustable links and rods.......back to oem non adjustable units now.

I think I've tried everything possible on Q except having new suspension designed from scratch!

Some how I missed the front strut tower brace until last year.....best investment to date after a 20mm rear bar.

Post by **maxnix** » Thu Jan 23, 2003 10:07 am

After all this, one thing I might try sometime in the future is springs that are 15%-20% stiffer than stock, but stock ride height. With the blues and the rear 20mm "a" bar, this seems it would be ideal.

Of course the car wouldn't look "cool", and it would be a little firmer, but I would accept that for a little less float over undulating irregularities.

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

Q45tech wrote:pounds per inch but again not sure if they are saying wheel rate or the springs alone ! Normally one would send a front and rear spring and let the engineers evaluiate the pitch to make sure it is linear.

On luxury cars there is so much rubber in seats and multiple bump stops AND the GAS charge must be calculated in shock as the Tokico do provide a little expansion lift which adds to the springs.

Normally one would install the whole assembly on a spring rate tester and cycle the system at varing stroke lengths and rates to get curves at different temperatures.

All in all it is complicated and the factory gets it just right for new components then the after market just adds some fixed percentage.........in the case of Eibachs they made the rear progressive in spring rate with a linear front.

Even a 10% error can lead to pitching of car body since the the tuning speed over interstate seams will vary........what speed are you asking for the system to be tuned to?http://www.efunda.com/DesignSt...#calch ... pensn.html

Ill FWD this to the Suspension guy and let you know what he says. Originally i was just looking to gut the stock strut and add an insert using the stock prings...But depending on the cost he might be able to remove the stock perch and weld it up for coilovers. I still need to get him some digital pics and measuments to see if he can work with the stock struts.

Terry

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

Dennis, thanks for the response. I'll admit, my sole reason for considering the Eibachs is for looks. I'm close on the tires (245/50's), just bought the Tokico Blues, and just found a 20 mm RSB in a junkyard for $50.

That being said, I may forego the springs for $$$ reasons alone.

Brian, Quella would "look good" even with 13" Daytons and 185/60's.

Post by **maxnix** » Thu Jan 23, 2003 10:07 am

AZhitman wrote:Brian, Quella would "look good" even with 13" Daytons and 185/60's.

Especially in the valley if you got the 5" spacers, man.

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

Now you're talking, Vato.

Post by **nadirgholi** » Thu Jan 23, 2003 10:07 am

Who is the maker of front strut column brace for Q? Where is the best place to get it?

Post by **Q45tech** » Thu Jan 23, 2003 10:07 am

Stillen sells a pretty one that is pricey.

I made some stress measurements [with a load cell] and the forces are high [over 400 pounds] yet the movement [ bending inwards outwards] of the strut towers is small [+-1/4"]............this translates to a +-0.5 degree camber change in WC transistion [radical left - right streering].

The new feel and stablity is quite noticeable when the bar is tight pushing the towers apart [in tension - back to as new position].

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

Stillen's STB was on sale for a good price last I checked - Maybe we could do a group buy if anyone else is in...?

Post by **DenverQ** » Thu Jan 23, 2003 10:07 am

ME!!! I am so down

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

If this group buy is big enough do you think that Stillen would sell other model STBs? Ive been holding out for one on my 92 Sentra, and my 97 Q45 has the stock unit:).

Terry

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

There's one for sale on eBay right now.

Post by **Tgvince** » Thu Jan 23, 2003 10:07 am

ill check it out thanks!

Post by **nadirgholi** » Thu Jan 23, 2003 10:07 am

I ordered one from Stillen last week. I opened it today to install it. To my surprise the mounting plates on the left and right are identical, meaning only the left plate has the right holes for the strut tower bolts. It is not adjustable either. What a piece of crap. This one is the only one they make and it was on sale for $129, regularly $199. I have to call them Monday and find out what they have to say about this fine part.

Post by **AZhitman** » Thu Jan 23, 2003 10:07 am

Keep us posted - I'd hate to see one of our new advertisers get off to a bad start.

Interesting - perhaps they accidentally neglected to include one of each side (you got "2 left feet").

Post by **nadirgholi** » Thu Jan 23, 2003 10:07 am

How about this thing not being adjustable? I don't see how the strut columns can be pull/push from each other using this part.

Q spring rates?

Q spring rates?

Stiffer Springs

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