Captive springs

[snwtoy]

Cutting springs isn't just going to affect spring rate.

Actually, cutting springs makes them stiffer. The shorter the spring the harder it will be. Ever stop to think how progressive springs work? Hint: the proximity of the coils has nothing to do with their rate!

Bout time a mod removed some of the extremely bad advice in this thread.

[RedMist]

Yep, thats why I said

Cutting springs isn't just going to affect spring rate. ... and then listed the stuff it also affects.

It's pretty obvious that cutting ups spring rates. In regards to progressive spring rates, again pretty elementary stuff. Variable winding or variable thickness as on the 917?

The Bunderson is reasonably complex in regards to spring rate. Front has dual element coilovers with a stopper based rate switchover. Placement of the coilover was important to get correct rising rates on the trailing arms. The stopper, rate of each element and the height of spring platform all important in setting wheel spring rates. The rear was doubly important as its rising rate Nitrogen springs, with tripple bypass remote res shocks. I set rear spring rate in seconds, using a reg and nitrogen bottle, per meet based on condition of track and fuel loading. Why Nitrogen and not air? Air does one thing when heated that doesn't make it a very good constant spring rate.

Bout time a mod removed some of the extremely bad advice in this thread.

I suggest they start with yours.

[RedMist]

If you are really desperate to lower your car then I suggest you do it properly. Buy yourself susprog 3D, spend a few months learning to use it. Study for several years on suspension geometry. Then alter all your cars pickup points, rack mounts, tie rod length, springs and shocks.

Still by the time you have done that you'll have probably decided that a stock ride height is much better for performance, road holding and safety.

Unless you're on a very flat race track.

or you could just cut them so they are not gonna fall out, then go for a drive and see if the handling is better or worse

oh no my car has cut springs, i'm obviously an evil baby killer, cry me a river

Actually I don't think your an evil baby killer. Just a prat. I have no desire to degrade the performance, or risk my safety on any of my cars just for sake of looks. I'll rather spend my time or money on something that makes my car handle or perform better.

Saying that, if you have to lower your car for looks, your advice in regards to maintaining captive springs is most certainly good.

[Loudtoy]

Seriously dude, if your going to risk someones life on your advice I suggest you get a clue.

Cutting springs isn't just going to affect spring rate. It alters the suspension geometry, bump steer, travel, scrub, camber caster toe.

Ever compressed a small spring like that in a pen, then let it go? It never bounces straight up and down! Car springs are somewhat similar, there is deflection if not held inih is why check by being captive! Even if the spring doesn't dislocate to the point where it doesnt evenly load the platform, its shock loading the platform every time it comes off by only a mm or so. Its only a matter of time before the platform or spring fails.

If you are really desperate to lower your car then I suggest you do it properly. Buy yourself susprog 3D, spend a few months learning to use it. Study for several years on suspension geometry. Then alter all your cars pickup points, rack mounts, tie rod length, springs and shocks.

Still by the time you have done that you'll have probably decided that a stock ride height is much better for performance, road holding and safety.

Unless you're on a very flat race track.

Which is why, with my rally car i have gone for standard heightish but with stiffer springs and shocks to suit wasn't to expensive an option considering i could have gone for coil overs or something equally expensive for about the same prive per corner as my entire setup.
Still for shortened shocks, and matching your spring and shock rates a little research for what you are doing, what other people are using and what success they are having with it plus knowing what kind of driving style they have and how they like there car to respond then comparing it with your driving style and experimenting with your own car is the way to get the stup you desire without the nastys of bump steer, snap over steer mid corner under steer etc. And it's especially easy to get the setup close to right if your not dealing with road degredation and surface change throughout the day

[RedMist]

Nice. What are you running?

Owned a couple of AE86 rally cars for a while. One here and one in the UK. Switched back to offroading... more abusive on body and mind.

[Loudtoy]

Nice. What are you running?

Owned a couple of AE86 rally cars for a while. One here and one in the UK. Switched back to offroading... more abusive on body and mind.

Got kp starlet currently stripped for painting and 180b thats sitting in the shed as an excuse still to go to hill climbs etc while the starlet waits for me to get some motivation happening.
really the datsun is for sale just not advertised anywhere

[gmacrae]

Its obvious that Redmist knows more about suspension than anyone else in this thread. Listen to him.

[RedMist]

Thanks for the vote of confidence. However most opinions here are valid. I'm just a staunch anti-ricer. There are safety and performance issues with altering ride height and I think many people here don't take these issues serious. If lowering the ride height gave any performance increase for road surfaces then I would be all for cutting springs. However I can't see a single plus for lowering a car on NZ roads.

I have owned a total of 7 race cars on a limited budget. It forces you to study suspension geometry extensively. Keeping things like bump steer, scrub, track changes, let alone basic caster, camber, toe in check is near to fuggin impossible.

It's extremely hard to control a wheel through 20 inches of travel. Hence the complexity of the systems in place on the Bunderson.

[RedMist]

If you want to study more on suspension geometry.

Race and Rally Car Source Book or "Competition Car Suspension" by Alan Staniforth are a good start. About a third of the material is copied between the two books.
The Carroll Smith "Tune to win" is an excellent reference.

Susprog3D is a very good extensive geometry modler.
Suspenison Alalyzer by performance trends is easier to work with, contains less bugs, but is limited by the suspension designs it can cater to.

[Lorollin]

I use to roll in a dx sedan with 4 coils outta da front and 3 frm bak. Front left spring fell out on normal road at 50ks, didnt reck my tire but put mean chunkz outta it. (same 1 fell out again lata on again) car drove allrite need to hav low pro tires wen u get real lo (helps the bounce). But i neva had cutz again

[Santa'sBoostinSleigh]

I use to roll in a dx sedan with 4 coils outta da front and 3 frm bak. Front left spring fell out on normal road at 50ks, didnt reck my tire but put mean chunkz outta it. (same 1 fell out again lata on again) car drove allrite need to hav low pro tires wen u get real lo (helps the bounce). But i neva had cutz again

well from your spelling and grammar we can tell you are a bogan


moral of the story, cut and/or uncaptive springs are illegal
see: http://www.landtransport.govt.nz/public ... -v2-1a.pdf


(bah sorry photobucket is being a hoe with my image)

[Scotty]

[kp60rally]

autolign in mt wellington on carbine road, $45.00 + gst a shock, cheap and safe, ive had shocks from 6 of my cars shortened there, they do a good job, best way is to use aftermarket springs and if your still not happy with the height get them reset. do it once and do it right is the best way,

[Sparkie]

if you read the pdf file properly you would realise that its only illegal without lvv certification not illegal fullstop provided they are captive.

funny cause i know people with certed captive cutties

[bad20v]

Oh! Oh! Oh! My turn! My Turn!!!

<--- THIS TOPIC!!!

[wde_bdy]

if you read the pdf file properly you would realise that its only illegal without lvv certification not illegal fullstop provided they are captive.

funny cause i know people with certed captive cutties

You should also know then that to get them certed they either need to done by a springmaker or have plain unground ends with no heat used in the cutting process. Most Toyota springs seem to have tapered or ground ends so the home job springs will never be legal.

Callum