High spring rate question
10-13-09, 12:52 PM
#2
Less travel = focusing the wear and friction-generated heat across a smaller length of the travel, would be my guess. Same mechanical energy absorbed within smaller space/shorter travel time = higher temperatures in smaller volume.
Just a guess, though.
Just a guess, though.
10-13-09, 02:46 PM
#3
Yeah, I have been searching google and all I can find is "Don't do it with stock shocks because we said so" stuff.
Although I did see a few places saying something along the lines of Koni's are not position sensitive, and they will work in any area of their stroke as long as it doesn't bottom out.
Although I did see a few places saying something along the lines of Koni's are not position sensitive, and they will work in any area of their stroke as long as it doesn't bottom out.
10-13-09, 03:24 PM
#6
The shocks are valved to control a certain spring rate and a certain unsprung weight(suspension etc.) If you run a higher rate than stock with a stock shock the valve will be overloaded and not do its job. Now I don't know if its will actually wear the shock faster or blow the valve to a point that soime of the shims get bent but it won't control the spring.
10-13-09, 03:36 PM
#7
The shocks are valved to control a certain spring rate and a certain unsprung weight(suspension etc.) If you run a higher rate than stock with a stock shock the valve will be overloaded and not do its job. Now I don't know if its will actually wear the shock faster or blow the valve to a point that soime of the shims get bent but it won't control the spring.
if you are upgrading spring do the shocks at the same time. if you don't have the money for both themn buy one then the other and install them togther.
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10-14-09, 12:10 AM
#15
When I bought my RX7 it had 450F and 300R springs with Illuminas on it. The struts/shocks worked pretty good but had to be run at setting 5 all of the time. The owner that put this together talked to Jim Susko about the setup and he said that those rates were about all that the Illuminas could handle. The shocks eventually wore out but I am not sure if this had anything to do with the spring rates or just 5 years of racing abuse.
I have since gone to 400F and 250R springs and run Koni struts and Pro Shocks on the rear. These spring rates match my driving style better and the struts/shocks work better for club racing as I have more of an adjustability range with the Koni's. The Pro Shocks are not adjustable but are a split valve shock - medium stiff on rebound/soft on compression.
My feeling is that what you are doing should be managable for Illuminas. The biggest thing to watch for is that you don't bottom the stuts out. That will do them in for sure.
On a Solo II Mustang I used to have I ran stock struts/shocks with really stiff springs. Nothing dramatic occured - the car just wasn't very fast and bounced around allot. Stock/HD shocks cannot damp stiff springs effectively. Whether or not they eventually fail is not relavent....they will be so bad you won't wait to find out.
I have since gone to 400F and 250R springs and run Koni struts and Pro Shocks on the rear. These spring rates match my driving style better and the struts/shocks work better for club racing as I have more of an adjustability range with the Koni's. The Pro Shocks are not adjustable but are a split valve shock - medium stiff on rebound/soft on compression.
My feeling is that what you are doing should be managable for Illuminas. The biggest thing to watch for is that you don't bottom the stuts out. That will do them in for sure.
On a Solo II Mustang I used to have I ran stock struts/shocks with really stiff springs. Nothing dramatic occured - the car just wasn't very fast and bounced around allot. Stock/HD shocks cannot damp stiff springs effectively. Whether or not they eventually fail is not relavent....they will be so bad you won't wait to find out.
10-14-09, 07:42 AM
#17
I feel that 350#/375# is the limit for Illuminas. I normally suggest the MR2 inserts for 375#/400#. Anything more than that and you need to mod the struts for race inserts.
The shocks will obviously work with those springs rates - just not for long. You are basically over working the valve system. When something is overworked it is not efficient.
-billy
The shocks will obviously work with those springs rates - just not for long. You are basically over working the valve system. When something is overworked it is not efficient.
-billy
10-14-09, 11:28 AM
#19
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I feel that 350#/375# is the limit for Illuminas. I normally suggest the MR2 inserts for 375#/400#. Anything more than that and you need to mod the struts for race inserts.
The shocks will obviously work with those springs rates - just not for long. You are basically over working the valve system. When something is overworked it is not efficient.
-billy
The shocks will obviously work with those springs rates - just not for long. You are basically over working the valve system. When something is overworked it is not efficient.
-billy
10-15-09, 01:47 AM
#20
Simple answer is this. The spring moves vertical energy from the road hitting the tire. and since energy can not be created or distroied without a shock after taking a bump the spring in theory would never stop moving. (that is why cars with blown shocks bounce forever after hitting a bump.) What the shock does is it converts the springs mechanical energy and converts it into heat. the higher the spring rate the more energy is present in a smaller area of the spring after hitting a bump and the less transfered through the body. therefore there is more heat to be disapated by the shock. A shock is valved to disapate a certin amount of heat controled through is valving and weather its gas or liquid. That's why you hear about gas/liquid shocks boiling or foaming over they're not desiged to dtransfer teh mechanical energy into heat fast enough. When shocks are not valved to dampen the spring it will wear out faster due to the degradation fo gas or fluid that is in the shock. Or you could have a valve in the shock break from bottoming out. the late great sport compact car had an amazing 6 or 8 part series on suspensions that expalined it all.
10-15-09, 12:42 PM
#22
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I need to get to some autocrosses or something if they have any around here.
10-15-09, 02:11 PM
#24
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CARTRIDGE, STRUT (FRT)
Nice alternative to Tokico Illuminas. Can hold up to higher spring rates than the Tokicos. Bilstein high pressure gas montube shock absorber. The superior damping ability helps improve handling and stability without sacrificing ride comfort. Instantaneously self-adjusting for changing road surfaces and their performance does not decline from age, use or heat. Heavy Duty setting fits all models. Requires ring nuts, 0000-04-7227-BL x2. #P30-0104
Notes: P30-0104
http://www.allshocks.com/bilstein/ht...RX-7&year=1979
$140 is more than the tokico, but its not $$$$$$$$
B4-B30-U226B1 is the bilstein ring nut
