johnny Posted January 18, 2008 Share Posted January 18, 2008 as my seach for a set of nitrons seems to have drawn a blank--and my 97 vx has a tiny (5") set of arrowstar springs on the front bils, what springs (length wise) should i be looking to go for? (shocks have groves machined in them/+platforms) its wide-track/mainly road use/175/13"cr500front- red arb i was thinking 250lbs -but dont know what length/where to get them? the rears are 180lb/fronts225lb according to a old arrowstar flat - floor sheet Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 18, 2008 Share Posted January 18, 2008 You can get them from Demon Tweeks or GPR, and no doubt other suppliers as well. Assuming you want to keep the same ride height, the compressed length of the new spring will be the same as the existing. Start by measuring that length (Lcomp), preferably with someone in the driving seat. Then jack up the car so that the spring is uncompressed, ie in its relaxed state, and measure again (Lrel1). Assuming your old spring info is correct you can calculate the load applied to the spring by taking the rate (225lbs/inch) and multiplying by the compression (relaxed length minus compressed length in inches = Lrel1-Lcomp). You now know the spring load (W) which will be the same for any spring rate at the same ride height. Incidentally this load is not the same figure as the corner weight, due to the geometry of the suspension. To calculate the relaxed length of the new spring: divide the load (W) calculated above by the new spring rate (250lb/inch) to get the COMPRESSION of the new spring in inches. Add that to the compressed length of the old spring (Lcomp) and you have your new spring relaxed length. This should work out as the new spring being a bit shorter than the old as its stiffer and therefore won't compress as much. Hopefully when you jack up the car the spring will be loose on the shock. If its very tight it may not be fully relaxed and you'll either have to guess or move the platform to measure accurately. The wide track ride height is more sensitive to spring length change than the standard setup due to the different angle of the spring/shock 'strut' so you want to be in the right ballpark. Hopefully you've got adjustable platforms otherwise you might struggle as the springs come in one inch length increments. You'll also need to specify the same spring internal diameter as they come in different sizes. Link to comment Share on other sites More sharing options...
Jason Plato Posted January 18, 2008 Share Posted January 18, 2008 do you not think 5" long spring is Ok ? If your intending changing to 250lb fronts then I would just stick with 5"and adjust the little tiny ride height difference with the platforms - nice and simple . I doubt you will feel the difference in 25lb (assuming your current spring rates are accurate @ the stated 225lb. I ran front 5" springs for years on the front - no issues . They are the same length as F3 springs Faulkner springs are reliable , good quality and available from faulkner themsleves or Merlin Motorsport @ castle combe and via mail order. here is C7 TOP Taffia rear gunner Link to comment Share on other sites More sharing options...
johnny Posted January 18, 2008 Author Share Posted January 18, 2008 Paul---thanks for all the info--i can understand it too- -so what your saying is if i put longer "standard"springs on the set up (ride height/rake) will be all to cock(so to speak) looking at the original bill for the arrowstar spring set (at club price ) the code is ASR300---I WONDER IF THAT COULD MEAN 300LB it was flat-floored by arrowstar at the same time as fitting--on the flat floor sheet it states 225lb--that said it was flat-floored again by arrowstar 3yrs later and they left the front rateings blank &put 200lb? for the rears this is all to do with my impression that the set up is to hard for the road as the guy i bougth it of used it track days---and i lost a filling 😬 Dave--what sort of lbs springs were your 5" springs? Link to comment Share on other sites More sharing options...
johnny Posted January 20, 2008 Author Share Posted January 20, 2008 just remeasured the front springs and their 3-1/4" long . i take it these are"nt meant for road use, any thoughts what to replace them with? Link to comment Share on other sites More sharing options...
Jason Plato Posted January 20, 2008 Share Posted January 20, 2008 I was running a k series at the time so my engine was about 30Kg lighter than your vx which would affect the spring rates and suspension setup . The springs were 250lb x 5" I'm still puzzeled as to why you appear to made your conclusion that 5" or 3.75" springs are unsuitable ? . does the spring go coil bound ?, does the spring have a long travel to deal with ?. Are the springs breaking ? For what its worth I would suggest a 7" x 275Lb spring on the front and std progressive rears if your on road use, and then adjust the height on your adjustable platforms . There should be a circlip grove at a few alternative positions on the damper body that you can use. If you have a circlip groove about 4" up the damper form the position you are currently at then this is the one I would try ... the other thing to do is to determine the spring rate you have first before you buy more. The billies are quite a hard riding damper anyway, so you may also consider buying new dampers and springs as a matched package before you buy springs for the billies ?. Springs are about £20 > 30 each inc vat + post what handling traits are you suffering ? or do you just think the ride is too hard ?. Or are you comparing the ride to a tin top road car ?. Are you using yoko 48R's ? - the ride is very harsh on these tyres, try ToyoR888 instead - huge improvement in ride with the softer sidewalls dave here is C7 TOP Taffia rear gunner Edited by - Dave Jackson on 20 Jan 2008 19:31:05 Link to comment Share on other sites More sharing options...
johnny Posted January 20, 2008 Author Share Posted January 20, 2008 Dave, as the handling seems to want to bounce me across the road on all but the smothest roads---following my mates standard hpc i have to back off in the twisty country lanes for fear of going bounceing through the hedge--i would"nt say it bottomed out--just not enough movement to soak up the bumps. The cars on 6" 175 cr500 fronts/8"205cr500rears---red arb front. rear--can bounce the rear off the car by hand--compared to mates standard hpc i would say its the same--rear arb on 2nd softest hole the rear springs are loose (can be turned by hand)with no one in the car--is that right? Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 20, 2008 Share Posted January 20, 2008 bump steer? Toe out? Knackered rear shocks if the springs turn with the car on the ground. How long are the rear springs? 10" 'ish is normal. Rear arb won't affect the stiffness of the rear suspension if you 'bounce' the car by pushing down in the middle of the back of the car. Sounds to me as though your entire suspension needs a good looking at! Try Gary May at Freestyle. Link to comment Share on other sites More sharing options...
johnny Posted January 20, 2008 Author Share Posted January 20, 2008 Paul if 10"ish is normal 😬--mine are normal-(well they look about that length)-plus their inverted like the fronts-arrowstar fitted new billies on the rear when they fitted the arrowstar spring set--they"ve done about 7,000mls would like to go to freestyle--but its a long way from me---and if i do it myself i can put my tuppence worth in at club meeting in pub car parks 😬 car set at slight toe-out(4mins)was 1%10mins out when i first got car borrowed a set of dunlop gauges & did it myself---maybe i should have that cheched Link to comment Share on other sites More sharing options...
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