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Damper Graphs Wanted.

djr81
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djr81 Grand Master

djr81

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Does anyone have any force velocity graphs of dampers installed on their Skylines?

I am trying to work out what damper rates would be suitable for a spring change & am having trouble getting any decent information out of the suppliers. If you could make mention of the spring rates they go with that would be great.

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BI6TIM Enthusiast

BI6TIM

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Good luck with that. Really, the only way you're going to get that info is if you have a friend with a shock dyno and can convince a bunch of people with the same car as you but also with all different types of shocks for you to remove from their cars and test on the shock dyno. Not likely.

Why do you feel you need to be so scientifically specific when it comes to shocks, there's a bunch of excellent options straight off the shelf that any suspension shop worth their salt should be able to match up to suitable springs for you.

I am manager at City Suspension in Brisbane and can discuss it with you if you want to give me a call at the office during the week, 3808 3266 ask for Tim.

Edited by BI6TIM
djr81 Grand Master

djr81

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The point is that once you have calculated the damper rate for bump & rebound and worked out the acceptable range on what you want for both ends of the car it would be nice to be able to tell by a means other than the usual salesman blandishments that the shocks are, infact, what you are after.

The information is not unknown or even unavailable. It is not a case of being so scientific, simply a case of being able to select a shock using some basic information.

The suspension shops match springs to cars & to dampers. But htey do so in such a broad range that makes me less than 100% comfortable with the selection.

Anyway, love to all, etc. :)

djr81 Grand Master

djr81

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I'm in the same boat, post any findings you get djr.

As much info I have at the moment is as follows. The numbers are based on the sprung weight of my car & hence will be different for others, obviously.

Stock R32 GTR info:

Front spring rate 2.4kg/mm & damper rate based on 0.3m/sec - assumed to be linear

Front bump damping ratio 0.25 (500N)

Front rebound damping ratio 0.89 (1746N)

Rear spring rate 2.7kg/mm & damper rate based on 0.3m/sec - assumed to be linear

Front bump damping ratio 0.24 (402N)

Front rebound damping ratio 0.66 (1108N)

Nismo R32 GTR info:

S tune damper set to the middle of 5 settings.

Front spring rate 5.5kg/mm & damper rate based on 0.3m/sec - assumed to be linear

Front bump damping ratio 0.36 (1079N)

Front rebound damping ratio 0.64 (1912N)

Rear spring rate 4.5kg/mm & damper rate based on 0.3m/sec - assumed to be linear

Front bump damping ratio 0.32 (686N)

Front rebound damping ratio 0.63 (1373)

Notes:

A reduction in srpung weight gives you an increase in damper ratio.

An increase in spring rate gives you a lower damper ratio.

What is deemed acceptable for bump & rebound ratios for the front & the rear is arguable. I am presently chasing some info from some of the damper manufacturers but who knows if they will come good.

Scooby Veteran

Scooby

Posted
Posted (edited)

try calling suspension technology australia in yass, nsw. for the reasons you're stating i had jap ohlins, bilstein pss9, sydneykid bilsteins, and konis both original and revalved dynoed there. john also had graphs of teins that from memory came off a 32 gtr. he's a font of knowledge and very good with this stuff. he used to work for eibach and has been in the game for donkey's. did brock's targa monaro suspension too. unfortunately i don't have the graphs anymore but he could prob be persuaded to part with the info.

good on you for going down this path, too. i've found once you decide to ask the really hard questions about what you're spending money on, and decide to do some research to get to the real truth with these things, the information dries up unless you persevere and get it yourself but it's worth it.

Edited by Scooby
djr81 Grand Master

djr81

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try calling suspension technology australia in yass, nsw. for the reasons you're stating i had jap ohlins, bilstein pss9, sydneykid bilsteins, and konis both original and revalved dynoed there. john also had graphs of teins that from memory came off a 32 gtr. he's a font of knowledge and very good with this stuff. he used to work for eibach and has been in the game for donkey's. did brock's targa monaro suspension too. unfortunately i don't have the graphs anymore but he could prob be persuaded to part with the info.

good on you for going down this path, too. i've found once you decide to ask the really hard questions about what you're spending money on, and decide to do some research to get to the real truth with these things, the information dries up unless you persevere and get it yourself but it's worth it.

Yes cheers. The have some good systems. I think (from memory) that getting them to go through the sheets for your car was well priced & that getting the dampers dynoed was equally good value. Just out of interest did you get them to produce a set of sheets for your car?

As for the second paragraph that is exactly what frustrates me in trying to modify a car. I don't reckon the questions are actually very hard but it doesn't mean they get answered.

Scooby Veteran

Scooby

Posted
Posted (edited)
Yes cheers. The have some good systems. I think (from memory) that getting them to go through the sheets for your car was well priced & that getting the dampers dynoed was equally good value. Just out of interest did you get them to produce a set of sheets for your car?

As for the second paragraph that is exactly what frustrates me in trying to modify a car. I don't reckon the questions are actually very hard but it doesn't mean they get answered.

lol your are spot on there djr. the questions are really basic, no-brainers even, but it's frustrating when no one knows the answers to the fundamentals and even more frustrating to think that people in the industry haven't bothered to find out. try getting empirical evidence on the often quoted RB30 harmonics issue or the benefit of dump pipes. i can't really blame the industry though, research does cost and if people are prepared to part with their money...

you prob know this but if you want to see whether a susp guy is thinking, ask what sort of bumpstops they use and why they chose that elasticity. if they use the term 'universal' ask how they can use the same units on a GTR as on a Civic. that's the thing with john, he has prob 20 different types because he understands the importance and with limited travel the 32 needs some thought in that area.

STA did produce graphs for the dyno, if that's what you mean. can't remember the cost but it was well worth the $ to know, particularly when i found that one set with 36 click adj only worked from click 25 onwards. imagine the stuffing around that saved in terms of trial and error.

Edited by Scooby

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