Springs "destroying" shocks?

cheshirecat · 07-01-2011, 03:38 PM

hahaha. :P

Andy124 · 07-01-2011, 04:38 PM

Quote:

Originally Posted by cheshirecat

I dunno man, I just don't like the tucked wheels, especially when you have the additional camber from the drop. With the camber evened out it'll probably look great as you say- I just love having the top of the wheel even with the fender.

Pic of mine with the spacers- this is before the 305s went on.

this is nice and perfect...10mm front and 15mm rear?

kenchan · 07-01-2011, 05:35 PM

more like 20/25, i thinks...

cheshirecat · 07-01-2011, 05:42 PM

yep, 20/25.

Vapiano · 07-05-2011, 12:52 AM

Quote:

Originally Posted by cheshirecat

I dunno man, I just don't like the tucked wheels, especially when you have the additional camber from the drop. With the camber evened out it'll probably look great as you say- I just love having the top of the wheel even with the fender.

Pic of mine with the spacers- this is before the 305s went on.

This is the drop I am looking for, did you do just springs only? If so, what brand and specs?

Thanks,

V.

cheshirecat · 07-05-2011, 08:40 AM

It's swifts with spacers.

whoLEEoh · 07-05-2011, 11:13 AM

delete post...double post

whoLEEoh · 07-05-2011, 11:22 AM

Quote:

Originally Posted by Econ

naive friend is naive

i guess you dont know much about suspension...yes your shocks will blow prematurely because the spring is shorter and not only that the spring rate is way more aggressive than what the stock shock is valved for. if someone with swift springs last 20-25k miles on them id be surprised.

wheee! · 07-05-2011, 11:31 AM

Quote:

Originally Posted by whoLEEoh

i guess you dont know much about suspension...yes your shocks will blow prematurely because the spring is shorter and not only that the spring rate is way more aggressive than what the stock shock is valved for. if someone with swift springs last 20-25k miles on them id be surprised.

Let the games begin!

CFZ · 07-05-2011, 12:30 PM

Quote:

Originally Posted by cossie1600

You are kidding right. Why do you think Bilstein charges $60+ for each shock rebuild. They might use the same seals, but the actual amount of gas or oil and the size of orifice are completely differently. If you ever send your shock in for a rebuild, they would ask you everything from wheel/tire weight to spring rate and all the little stuff. When your spring rate goes up 20-30% harder/quicker over what the shocks are designed for, what do you think absorbs the impact along with the spring? The stiffer spring rate effects the compression and the rebound stroke as the shock has to work much harder/quicker to return the shock back to its original position. I have nothing against this particular spring, but it's a fact that you will likely decrease the useful life of the shock simply from doing stuff like that. It could be 1000 miles, it could be 75K miles. You just don't know, but you are shortening the life of this shock by doing it. It's just common sense, the spring is 20-30% stiffer than stock!!!

(STRAIGHT FROM BILSTEIN'S WEBSITE) Interaction between spring and damper
When a car passes over an obstacle, this first has an impact on the spring, which must not be hampered by excessive damping performance on the part of the shock absorber. When a car passes over a bump in the road, for example, the obstacle forces the wheel up into the wheel housing. In the process, the spring is compressed. The shock absorber is now in its compression stage. Once the spring has levelled out the obstacle, the shock absorber has to slow down the movement of the spring as it releases its tension with great force. The shock absorber is now in its rebound stage. Compression stage (compressing of the springs and the damper, e.g. when driving over bumps in the road) = usually approx. 25% of the damping force. Rebound stage (when the spring pulls the damper apart) = usually approx. 75% of the damping force.

Conclusion: A spring with a higher spring rate (sport or lowered spring) will only work at its best in conjunction with the appropriate high-performance or sports shock absorber.

No Im not kidding you.

I dont know why you put up the pricing of the rebuild for, but are you seriously thinking that for a 60 dollar rebuild, they are going to be swapping out entire pistons for you?? No. In other words the orifices are all the same.
Also shock fluid amount is only slightly offset by the thicker shimstacks used for the rebuild.

When you revalve a shock for a certain rate they change and adjust the shim stacks, they try to give the most optimum or the most popular shock characteristics for the rates you are running for a particular vehicle. Sudden impacts on the shock generally do not affect premature wear on the shocks either because shocks have this thing called blowby (blowoff) this is when there is a high speed movement of the shock the valving goes to zero. So in other words if you run over uneven bumps that make sudden impacts in your suspension. This not only saves the shocks from blowing out but also retains traction through uneven surfaces.

The little article you used for your argument explains why you should valve the shock to what ever rate you use for optimum performance. It does NOT support your argument for a shock having a shorter lifespan. In fact nothing you stated does.

Unless you have a pos shock with a completely progressive dyno plot for the shock, it will not affect the shock life.

Thanks

cossie1600 · 07-05-2011, 02:51 PM

before i start, let me just say you are right about the basic principal of how to build a shock, except the shock you mentioned are the ones used for small applications like rc cars or machine dampeners....

modern car shocks use fluid and air (nitrogen normally) to dampen the energy from the spring. the shock converts the energy into heat as it dampens the load bfrom the spring. when you increase spring rate and load on the shock, what do you think happens to the oil that is inside it. it heats up beyond what they are designed for. go see what your engine oil looks like after a track day vs a few weeks cruising on the interstate.

also using your theory, we would never have blown shocks since they can just install over size valves and extra reservoir for oil are useless

tyyping on a phone, sorry for the typo

CFZ · 07-05-2011, 05:19 PM

Cossie, Seeing as though I actually build shocks all the time for my late models, I know a little more than some about shocks. Yes Nitrogen gas is used to put pressure into the shock to prevent hysteresis. I do not know anything about RC cars.....

The oil is not transferred into heat, There is no warm up period of a shock or anything like that. It is restricted through the valving of the shock. The oil goes through the piston of the shock and is restricted through the stacks of shims. the more shims the less they flex making the valving stiffer. Now this is done on both sides of the piston to adjust rebound on one side and compression on the other. The shock oil generally does not change color. There are different weight oils depending on valving of the shock, but most racers in my experience uses a very lightweight shock oil and adjusts valving through the shims. It is actually the opposite of what you are saying, heat is one of its enemies.

When I say changing the valving of a shock I dont literally mean changing out the valves like you would in an engine. By valving I mean changing the dynamics of the shock through the shim stack. Which is a common term.

When you use shocks for a long period of time the oil does get inconsistent, but this is because of few things, When racing for long periods of time they obviously heat up like any hydrolic system.
Twin-tube shocks are even worse off because the nitrogen and the shock oil physically mixes itself up causing cavitation.

The reason why shocks blow is because the seals and o-rings eventually wear out. Or bottoming out the shocks.

Signs on a twin tube shock
-leaking
Signs from a monotube
-leaking
-the shaft does not push itself back out when compressed (gas is in a seperate chamber so the secondary piston seal is blown)

I dont know where you are getting your information from but either Im not understanding you (which is likely the case) or you have some weird shock made but some kind of mad scientist.

From what you are saying warn out oil is the cause of blown shocks. Which does not make much sense. From our experience oil temps going up does increase inconsistencies but nothing makes it blow. And like I said before the stiffer spring minimizes movement in the shock, A soft spring will obviously increase movement, but the speed of the movement in a stiffer rate spring will be increased.

cossie1600 · 07-05-2011, 08:39 PM

I think you might have misunderstood me on some issues. Here is what I meant to say. Heat is one of the factor why shocks fail. I am saying lowering springs and stiff springs can contribute to that as the shocks have to work harder to absorb the motions from the spring (This spring might not be low enough to ride the bumpstop, but that can kill the shocks too). All the extra motions create heat, which then breaks down the oil. Oil is a lubricant, the constant heating and cooling of oil will break it down eventually. Seals can fail on a shock for variety of reasons, the breakdown of oil can certainly be a part of it.

Nitrogen in a street car's shock is to prevent aeration (foaming bubbles), not sure how it causes it. I can see it when you completely overheat the shock.

Quote:

Originally Posted by CFZ

Cossie, Seeing as though I actually build shocks all the time for my late models, I know a little more than some about shocks. Yes Nitrogen gas is used to put pressure into the shock to prevent hysteresis. I do not know anything about RC cars.....

The oil is not transferred into heat, There is no warm up period of a shock or anything like that. It is restricted through the valving of the shock. The oil goes through the piston of the shock and is restricted through the stacks of shims. the more shims the less they flex making the valving stiffer. Now this is done on both sides of the piston to adjust rebound on one side and compression on the other. The shock oil generally does not change color. There are different weight oils depending on valving of the shock, but most racers in my experience uses a very lightweight shock oil and adjusts valving through the shims. It is actually the opposite of what you are saying, heat is one of its enemies.

When I say changing the valving of a shock I dont literally mean changing out the valves like you would in an engine. By valving I mean changing the dynamics of the shock through the shim stack. Which is a common term.

When you use shocks for a long period of time the oil does get inconsistent, but this is because of few things, When racing for long periods of time they obviously heat up like any hydrolic system.
Twin-tube shocks are even worse off because the nitrogen and the shock oil physically mixes itself up causing cavitation.

The reason why shocks blow is because the seals and o-rings eventually wear out. Or bottoming out the shocks.

Signs on a twin tube shock
-leaking
Signs from a monotube
-leaking
-the shaft does not push itself back out when compressed (gas is in a seperate chamber so the secondary piston seal is blown)

I dont know where you are getting your information from but either Im not understanding you (which is likely the case) or you have some weird shock made but some kind of mad scientist.

From what you are saying warn out oil is the cause of blown shocks. Which does not make much sense. From our experience oil temps going up does increase inconsistencies but nothing makes it blow. And like I said before the stiffer spring minimizes movement in the shock, A soft spring will obviously increase movement, but the speed of the movement in a stiffer rate spring will be increased.

wheee! · 07-05-2011, 09:07 PM

On Swifts own website, they say that the stock shocks will work fine but they recommend that performance shocks be installed.

Quote:

Originally Posted by swift

2. Increase in spring rate to further enhance cornering speed through entry & exit. The increase in spring rate is based on the vehicle factory stock valving settings. Sport Springs Spec-R is increase to the optimal rate that the stock shocks can handle. Higher performance shocks are not required, but recommended.

DJ-of-E · 07-06-2011, 08:10 PM

Quote:

Originally Posted by wheee!

On Swifts own website, they say that the stock shocks will work fine but they recommend that performance shocks be installed.

If that's the case, what would be "performance" shock for the 370z? KYB AGX hahaha

07-05-2011, 11:13 AM	#37 (permalink)
whoLEEoh Premium Member Join Date: Oct 2010 Location: Miami,FL Posts: 647 Drives: 2010 370z NISMO Rep Power: 16	delete post...double post __________________ 2013 Boss 302 Last edited by whoLEEoh; 07-05-2011 at 12:13 PM.

07-05-2011, 05:19 PM	#42 (permalink)
CFZ Base Member Join Date: Jul 2010 Location: F-Town Posts: 134 Drives: 2010 370Z Rep Power: 234	Cossie, Seeing as though I actually build shocks all the time for my late models, I know a little more than some about shocks. Yes Nitrogen gas is used to put pressure into the shock to prevent hysteresis. I do not know anything about RC cars..... The oil is not transferred into heat, There is no warm up period of a shock or anything like that. It is restricted through the valving of the shock. The oil goes through the piston of the shock and is restricted through the stacks of shims. the more shims the less they flex making the valving stiffer. Now this is done on both sides of the piston to adjust rebound on one side and compression on the other. The shock oil generally does not change color. There are different weight oils depending on valving of the shock, but most racers in my experience uses a very lightweight shock oil and adjusts valving through the shims. It is actually the opposite of what you are saying, heat is one of its enemies. When I say changing the valving of a shock I dont literally mean changing out the valves like you would in an engine. By valving I mean changing the dynamics of the shock through the shim stack. Which is a common term. When you use shocks for a long period of time the oil does get inconsistent, but this is because of few things, When racing for long periods of time they obviously heat up like any hydrolic system. Twin-tube shocks are even worse off because the nitrogen and the shock oil physically mixes itself up causing cavitation. The reason why shocks blow is because the seals and o-rings eventually wear out. Or bottoming out the shocks. Signs on a twin tube shock -leaking Signs from a monotube -leaking -the shaft does not push itself back out when compressed (gas is in a seperate chamber so the secondary piston seal is blown) I dont know where you are getting your information from but either Im not understanding you (which is likely the case) or you have some weird shock made but some kind of mad scientist. From what you are saying warn out oil is the cause of blown shocks. Which does not make much sense. From our experience oil temps going up does increase inconsistencies but nothing makes it blow. And like I said before the stiffer spring minimizes movement in the shock, A soft spring will obviously increase movement, but the speed of the movement in a stiffer rate spring will be increased. Last edited by CFZ; 07-05-2011 at 05:26 PM.

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07-01-2011, 03:38 PM	#31 (permalink)
cheshirecat A True Z Fanatic Join Date: Jan 2009 Location: Florida Posts: 1,428 Drives: N54 135i Rep Power: 292	hahaha. :P

07-01-2011, 05:35 PM	#33 (permalink)
kenchan A True Z Fanatic Join Date: Aug 2009 Location: N/A Posts: 76,801 Drives: N/A Rep Power: 141521	more like 20/25, i thinks...

07-01-2011, 05:42 PM	#34 (permalink)
cheshirecat A True Z Fanatic Join Date: Jan 2009 Location: Florida Posts: 1,428 Drives: N54 135i Rep Power: 292	yep, 20/25.

07-05-2011, 08:40 AM	#36 (permalink)
cheshirecat A True Z Fanatic Join Date: Jan 2009 Location: Florida Posts: 1,428 Drives: N54 135i Rep Power: 292	It's swifts with spacers.

07-05-2011, 02:51 PM	#41 (permalink)
cossie1600 A True Z Fanatic Join Date: Jun 2009 Location: californee way Posts: 5,380 Drives: 370, Leaf Rep Power: 30	before i start, let me just say you are right about the basic principal of how to build a shock, except the shock you mentioned are the ones used for small applications like rc cars or machine dampeners.... modern car shocks use fluid and air (nitrogen normally) to dampen the energy from the spring. the shock converts the energy into heat as it dampens the load bfrom the spring. when you increase spring rate and load on the shock, what do you think happens to the oil that is inside it. it heats up beyond what they are designed for. go see what your engine oil looks like after a track day vs a few weeks cruising on the interstate. also using your theory, we would never have blown shocks since they can just install over size valves and extra reservoir for oil are useless tyyping on a phone, sorry for the typo