![]() 12/03/2014 at 12:32 • Filed to: ghetto mods, murdersofa | ![]() | ![]() |
What if I cut off a coil of my front springs, then spaced it back out to stock length with a large metal bushing or hockey puck so that the car rides at the same height but now has the higher spring rate you would get from cutting a coil? This would retain my alignment I just had done, and hopefully help the Sofa corner better.
And before you say "Get lowering springs" they don't exist for this car. There are some for the Bonneville which is the same platform, but they're several hundreds of dollars and I would also have to get an alignment.
EDIT: Why can't I put in a title with the new editor?
![]() 12/03/2014 at 12:33 |
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What if I cut ... my front springs
no
![]() 12/03/2014 at 12:33 |
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Brilliant argument. I bow before your well-thought-out points and reasoning.
![]() 12/03/2014 at 12:34 |
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Let me rephrase. As someone who specializes in transportation safety, no.
![]() 12/03/2014 at 12:35 |
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The only legitimate concerns I've heard about cutting springs is that it increases NVH, something I give fewer than 0 fucks about.
EDIT: well, and "don't use a blowtorch because it will make your spring brittle and likely to asplode"
![]() 12/03/2014 at 12:36 |
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Natural frequencies, how do they work?
![]() 12/03/2014 at 12:37 |
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wat is car
![]() 12/03/2014 at 12:37 |
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That still pertains more to ride comfort than safety, though it could be argued a bouncy ride is less safe than a smooth one depending on the driver.
![]() 12/03/2014 at 12:38 |
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I cut my springs. Car is kill.
![]() 12/03/2014 at 12:39 |
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The spring's rate stays the same, no? It's just shorter. It's not like you're twisting it tighter or making the steel magically springier.
Listen to Uncle Sweden on this one, please.
![]() 12/03/2014 at 12:39 |
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He'll just have to drive that much faster.
![]() 12/03/2014 at 12:39 |
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It could also pertain that unless you can demonstrate through vibration testing that your new spring-damper system is within a safe range, your new suspension could cause your front end to fail.
![]() 12/03/2014 at 12:40 |
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A little-used legal justification for speeding.
![]() 12/03/2014 at 12:41 |
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I can't believe I'm saying this outloud...but I agree with For Sweden. Don't cut springs, its not a good idea. If you want more spring rate, get air support bags like coil rite
http://riderite.com/Coil-Rite%20De…
It will firm up that ride REAL good. Anything that will force pressure against the coil and limit the travel.
![]() 12/03/2014 at 12:41 |
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That's basically where I stopped reading.
![]() 12/03/2014 at 12:41 |
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You're talking to a guy who drilled holes in his front strut towers and ran metal cabling from the strut towers down to the shocks to preload his suspension .
![]() 12/03/2014 at 12:41 |
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Nope. The ability to take up a certain amount of deflection is spread out over the whole length of the spring. A shorter spring under the same deflection has a higher relative deflection per "ring" of the coil. Shortened springs are stiffer - reduce length by 20%, increase the k by 25%.
![]() 12/03/2014 at 12:42 |
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And before you say "Get lowering springs" they don't exist for this car. There are some for the Bonneville which is the same platform, but they're several hundreds of dollars and I would also have to get an alignment.
Do it right, or don't do it at all. I speak from experience. Over the years, I have learned when I try to cut corners, I end up spending the more than if I would have went with doing it right in the first place due to issues that arise from cutting said corners.
![]() 12/03/2014 at 12:42 |
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I can't imagine assembling a critical system of your car with damaged car parts and non-car parts is a good idea
![]() 12/03/2014 at 12:42 |
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This is true, in fact, you are actually reducing the load capacity on your springs, since its coil diameter + number of coils = capacity.
![]() 12/03/2014 at 12:43 |
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I once had a tire vibration at 63 that smoothed out somewhat at 70+. It was my civic duty to drive safely.
![]() 12/03/2014 at 12:44 |
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Aah, increased harshness quickening wear and increasing potential of failure of other parts of the suspension?
I really don't see that happening with just one missing coil. The roads here are good, and this car has one of the most ludicrously overbuilt suspensions I've seen this side of a truck.
Also, considering what it has now is luxury car suspension, even a doubling or tripling in harshness is still better than many stock cars I've driven.
![]() 12/03/2014 at 12:44 |
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It raises the effective rate, but lowers the load capacity.
![]() 12/03/2014 at 12:45 |
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Well now I've got another idea for a tech article that no won will read! to the internets!
![]() 12/03/2014 at 12:45 |
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I don't think those will work on my fronts; I have a shock absorber in the middle of the spring.
Air bags would be awesome, but I'm on a budget of $broke and tired of the excessive body roll from this boat.
![]() 12/03/2014 at 12:46 |
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That's horrifying.
![]() 12/03/2014 at 12:47 |
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Body roll is a function of many things. here is the bottom line though...its the murder sofa. Love the sofa and safe the monies for something not sofa when you are ready.
![]() 12/03/2014 at 12:47 |
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The short summary of that article: taking away some of the ability of a spring to compress and making it compress further per coil and closer to the limit for a given amount of soak isn't necessarily a good idea, even if it makes the ride stiffer.
![]() 12/03/2014 at 12:52 |
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Don't do it.
![]() 12/03/2014 at 12:52 |
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"Something not sofa" is years down the road, at least. It kills me that the work I've put in this could make it a decent sporty machine if I could JUST GET IT TO CORNER BETTER. It pisses me off that there's that one huge shortcoming in my car for which there is absolutely zero aftermarket, basically forcing me to ghetto something together.
Perhaps getting some stiff rubber and stuffing (obviously more involved than this, but for the sake of brevity I'm stuffing it) it between coils so it takes more force to compress them? This would be a reversible solution, as well as adjustable (more or less rubber).
![]() 12/03/2014 at 13:03 |
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It can be done, but is not trivial to do safely. And just increasing front spring rate will make the car understeer incredibly, while making the ride much more "pitchy" - your car will plow and when it goes over bumps it will mimic the motion that makes people puke on boats.
![]() 12/03/2014 at 13:41 |
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There is a ride frequency impact from cutting springs (or inserting packers) and it's more than just ride harshness. The dampers and springs are tuned to control primary body motion for given sprung and unsprung mass, wheelbase, trackwidth, etc. When you effectively increase the spring rate without an appropriate adjustment in damping, undesirable handling behavior can result in lack of directional stability due to the underdamped primary body motion of the vehicle.
I know that people have been cutting springs and inserting spring packers for decades and survived. It's a short-cut way to convince yourself that you have improved the performance of your car. You should really consider a coordinated spring-rate and damping change.
In a past life, I did vehicle dynamics and suspension tuning for an OEM. There is much time and money spent on making the ride & handling correct. Please do not resort to short-cut methods to modify your suspension. It makes vehicle dynamicists cry. There are better, albeit more costly, alternatives to increasing the handling performance of your car.
![]() 12/03/2014 at 13:53 |
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a) If you're going to do it, don't do just the fronts or you'll turn it into an understeery pig. The inside front wheel will unload faster than the inside back one, which means the outside front one will do more work than the back one, which means more slip and lower ultimate grip at the front. Find a way to stiffen up the rears too.
b) Also lengthen the bumpstops, in proportion to how much you've increased the fully compressed length of spring + spacer combined. Otherwise your spring is probably now a metal-to-metal bumpstop. Which leads directly to broken suspension when you hit a big bump. Which will happen more often because you now have less bump travel.
c) Total extended spring length will now be shorter, so make sure the whole mess can't come loose at full rebound and the spring or spacer fall out or re-seat itself wrong - that's probably the single most dangerous mistake people make with ghetto lowering kits.
d) Be aware that damping rates are matched to spring rates, and by messing round with one and not the other, especially at one end only, it's possible to create a car with unexpected evil behaviours, so don't take it on public roads till you've hooned it enough on private, bumpy, roads to be sure you haven't managed that
e) On a barge like yours, stiffer springs probably won't help much - it may feel sportier because the ride's worse, and turn-in may improve a little, but grip and controllability won't change a lot, and it'll be more disturbed by bumps. Best bang for buck in handling improvement for a big car's usually polyurethane bushes, if you haven't done that already.
f) What ForSweden said
g) edit: actually, now I think about it, not what ForSweden said. Do it, have fun doing it, play with the result, have fun with that, learn some stuff, have fun with that too. But make sure you can put it back the way it was becausue you'll probably want to, and don't use it in such a way as to endanger anyone when it all goes horribly wrong.