oldrx Posted December 26, 2016 Share Posted December 26, 2016 Anyone clued up on suspension know what an approx min Spring length would be to still retain decent drive ability? With a 14in wheel and 195/45 tyres with top of tyre level with gaurd (dummied up jacking wheel up) the compressed Spring length will be about 130 mm. My factory perch is only around 30mm higher than where a weld on one would have to go so coul get an extra 30mm Spring length here but not sure it's worth It. [/url] Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 2, 2017 Share Posted January 2, 2017 This is a question that has been asked many times and the answer is relative to the amount of Back and Kidney pain you can tolerate or whether the police are watching. All you need is 3 coils and the top and bottom coils are shaped so they sit in the seat properly so just uses 1 working coil. (in fact even less than 1 coil working will do). But the more coils you can fit into that gap the better the car will ride even with reduced travel. This usually means a call to a Spring Maker. 1 Quote Link to comment Share on other sites More sharing options...
oldrx Posted January 3, 2017 Author Share Posted January 3, 2017 Should mention must be certable, happy to get custom springs, for the cost might be comparable to coilover kit where you can often specify Spring length and rate Quote Link to comment Share on other sites More sharing options...
Frosty Posted January 3, 2017 Share Posted January 3, 2017 If race trend helps you see mostly 8" and 10" springs in circuit cars. While 6" ones are available they don't give enough functional travel to be used in much more than display cars when you want them as close to the floor as possible. It also answers your question, 200mm or 8" is about as short as you can go and still have working suspension, a 6" one just doesn't have enough working range even in a race car where 2" of travel is a lot. Quote Link to comment Share on other sites More sharing options...
oldrx Posted January 3, 2017 Author Share Posted January 3, 2017 Right, how do people get their cars so low? I guess they just have suspension that doesn’t do much. Measured bump stop travel last night, with a 50mm lower arm spacer i will have 65mm flange to flange (travel will be 65mm less thickness of after market bump stop when i get some - maybe 10mm thick?). 1 Quote Link to comment Share on other sites More sharing options...
Bling Posted January 8, 2017 Share Posted January 8, 2017 Yeah in many cases the suspension on super low cars is setup for looks, so performance isn't the main priority. With the likes of weld on sleeves, the springs used are much smaller diameter, so they can sit much lower than factory perches. 30mm of extra spring length will always be good. If I was going super low, i'd go weld on stuff for sure, you can set it up exactly how you want. Using factory perches does limit you quite a bit in comparison. From the photo, it looks like you could even get more than 30mm lower if you went aftermarket weld on sleeve option? Just my opinion though. Quote Link to comment Share on other sites More sharing options...
oldrx Posted January 8, 2017 Author Share Posted January 8, 2017 Yeah think i will go weld on or the set up where the whole spring assembly screws into the strut tube to avoid compressing the spring to adjust height. Guy on Ausrotary looks like he does a good job of them (link below). Problem is my wheels wouldnt clear even the smaller dia spring with a lower perch, currently have approx 10mm clearance between tyre and strut tube in pic above. Dumb question but does the spring usually sit inboard of the wheel? Must do i'm guessing. If so my wheels are going to have to move outboard around 30mm. Wheel is 14 x 6.5in and already tyre is up against gaurd (will prob roll inner lip part) maybe i need to narrow it to 5.5in to clear a 60mm ID coilover spring. Or a big ass spacer and small gaurd flare. http://ausrotary.com/viewtopic.php?f=48&t=234161&hilit=adjustable+suspension Quote Link to comment Share on other sites More sharing options...
Roman Posted January 8, 2017 Share Posted January 8, 2017 If you think there's even the slightest possibility of changing spring rates later on. I'd go adjustable seat and 62 or 65mm ID springs. As they're common sizes so springs are cheap, got a pair of mine brand new for a box of beer. Vs paying $200 per set for oddball sizes. One thing that determines spring rate is the total length of wire in the spring. So a common way to manufacture the different spring rates for coilovers is to use same wire thickness but then shorter overall length/height for higher spring rate. If you have an adjustable height spring seat and set it up for springs that are on the soft side, you'll be able to switch to stiffer springs without dramas if you need to so long as the spring seat can wind up to suit. but good to have some available spring seat movement both up and down. I find that my car is on the border of too stiff for road with 5kgmm and 3.5kgmm springs, when doing some backroad doorts the front wheels start to skip off the road on undulations. 1 Quote Link to comment Share on other sites More sharing options...
Snoozin Posted January 8, 2017 Share Posted January 8, 2017 55 minutes ago, oldrx said: Yeah think i will go weld on or the set up where the whole spring assembly screws into the strut tube to avoid compressing the spring to adjust height. Guy on Ausrotary looks like he does a good job of them (link below). Problem is my wheels wouldnt clear even the smaller dia spring with a lower perch, currently have approx 10mm clearance between tyre and strut tube in pic above. Dumb question but does the spring usually sit inboard of the wheel? Must do i'm guessing. If so my wheels are going to have to move outboard around 30mm. Wheel is 14 x 6.5in and already tyre is up against gaurd (will prob roll inner lip part) maybe i need to narrow it to 5.5in to clear a 60mm ID coilover spring. Or a big ass spacer and small gaurd flare. http://ausrotary.com/viewtopic.php?f=48&t=234161&hilit=adjustable+suspension Definitely go the latter setup with the body-length adjustable style (screws into the strut tube). It will afford many more options for spring length and the ability to retain lowness - the softer spring rates in 62 or 65mm race coils are generally only available in the longer spring lengths, so with a straight weld-on sleeve to the strut you'll find it will always be a ride height compromise should you wish to change spring rate. 2 Quote Link to comment Share on other sites More sharing options...
oldrx Posted January 8, 2017 Author Share Posted January 8, 2017 1 hour ago, Snoozin said: Definitely go the latter setup with the body-length adjustable style (screws into the strut tube). It will afford many more options for spring length and the ability to retain lowness - the softer spring rates in 62 or 65mm race coils are generally only available in the longer spring lengths, so with a straight weld-on sleeve to the strut you'll find it will always be a ride height compromise should you wish to change spring rate. Yeah this seems a better way to go, wonder how hard it is to DIY... Off to cert thread to search about spacers, guessing if they are bolt on i can go nuts... Quote Link to comment Share on other sites More sharing options...
Snoozin Posted January 9, 2017 Share Posted January 9, 2017 Pretty simple. Theres some pics in my build thread of how we did the ones on my KP 1 Quote Link to comment Share on other sites More sharing options...
oldrx Posted January 9, 2017 Author Share Posted January 9, 2017 You happy with the Fortune Auto product quality? Have emailed for a quote. Quote Link to comment Share on other sites More sharing options...
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