Tracer-X Posted March 17, 2012 Share Posted March 17, 2012 My 31-year-old chassis modification book tells me that K=(W^4 x G)/(8ND^3), where K=spring stiffness in lbs/in, W=wire diameter in inches, G = 12,000,000 for steel springs, N=number of active coils (free coils + 1/2), and D = diameter of the coil measured to center of wire, in inches. So, uh, there. I'm another expert now. Do I get a star? I've got equations for leaf springs, too, for whoever decides that what their LGT really needs is a live rear axle. But the author of my book also recommends putting your springs in the oven to shorten them. Just compress it and stick it in the oven at 400 for "a few minutes." It's very scientific. "With luck it is not too short!" But don't worry, since "any differences can be made up with metal shims." Because racecar. (thanks, Tracer-X!) So glad to see you putting that book to good use! Jump on it, Let's do it, Ride it, My Pony... EL4NFZT7 Link to comment Share on other sites More sharing options...
Chris GTO TT Posted March 17, 2012 Share Posted March 17, 2012 Increase Flo = Increase Show or is it Increase Flo = Increase Go Needs more Flo:p http://www.insurancequotes.org/wp-content/uploads/2012/03/Flo-Progressive-Car-Insurance-Girl.jpg 2003 Baja 5MT 2016 Outback 2.5i Premium w/Eyesight Link to comment Share on other sites More sharing options...
dtmenace Posted March 17, 2012 Share Posted March 17, 2012 you guys are all haters! this is umerica, so turbospringcutterguy can do anything he wants! *subscribing to OP's local obits as well Link to comment Share on other sites More sharing options...
Turkeylord Posted March 17, 2012 Share Posted March 17, 2012 Subscribing, because I want to be here when BAC5.2 actually responds. I know more about the design and modification of springs than everyone in this thread, combined. Period.No, you don't. Link to comment Share on other sites More sharing options...
BAC5.2 Posted March 17, 2012 Share Posted March 17, 2012 CAN you cut springs? Yes. SHOULD you cut springs? Not really. Subaru springs, from what it looks like, are simply rolled off of a reel, then cut at the end of the roll. They are rolled directly into their final shape. They are cleaned up after, then go through heat treatment and maybe even shot-peening (i've never seen under the paint on a Subaru spring to be sure). To cut the spring after it's been manufactured does put the cut end at some risk for damage. Temperatures during cutting, if done poorly, could feasibly reach the anneal point for the steel, and you'd get some localized material failure under heavy stress. Also, quenching after a poor cut job, will almost certainly cause failure down the road as the end material is now quite hard and very brittle. A lot of the cut-spring Honda accidents are caused by this when the owner cut them with an oxy-torch and tosses them in a bucket of cold water. The "proper" spring cut method is actually a little barbaric. I read about it in a chassis engineering book I had that was written sometime in the late 80's, early 90's. They suggest cutting springs at most a half-coil, and only on non-trimmed springs (i.e. a 2.5" coilover spring, with it's ground ends, shouldn't be trimmed). That book has you cut half of a coil off, then heat the coil below the cut to allow you to re-form it to match the pre-cut profile, then letting it cool at room-temp. That last bit, like I said, was the source of most Honda problems. They'd cut 2-3 coils off, stuff them in the toilet to quench them, and wonder why their springs failed 4 months later. By cutting and letting it air cool, you aren't altering the heat treatment significantly. All of that said, should you cut springs? No. The risk is pretty high, not just for breakage but for other failures (like unseating the spring and having it hit the tire). If you don't re-form the bottom of the spring, you can't be sure that it sits properly in the lower spring perch. If it doesn't sit properly, the chance of rotation on extension is pretty high, and that's a bad thing. If there is adequate preload to prevent the spring from hopping, and the spring sits reasonably well in the lower seat, and the spring wasn't quenched when cut then it seems like the OP did the job as well as it could have been done. Still, I'd say it was a worthless endeavor. The potential hazards, the potential for screwing up the cut (a few tenths off, and you could have different spring rates on either side of the car), and a new spring that could be too stiff for the damper (more of an issue on older cars) are all practical reasons I wouldn't do it. You will get a drop, and a slight increase in spring rate, but the drop->rate ratio is not in favor of keeping off the bump stops. The cut spring isn't stiff enough to compensate for the drop in height. [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
planelazy Posted March 17, 2012 Share Posted March 17, 2012 Whatchunoabout string theory What kind of string are we talking about here? http://hof.voyeurweb.com/i/201001/00000297_voyeur_peeking_thong.jpg Link to comment Share on other sites More sharing options...
LosAngelesLGT Posted March 17, 2012 Share Posted March 17, 2012 Thats whale tale theory not string theory. Fish man, FISH! (yes I know a whale is not a fish, STFU) Link to comment Share on other sites More sharing options...
planelazy Posted March 17, 2012 Share Posted March 17, 2012 Fish.. mammal... eh http://gazmegfek.vateraauto.hu/wp-content/uploads/2011/11/CloseEnough.png Link to comment Share on other sites More sharing options...
LosAngelesLGT Posted March 17, 2012 Share Posted March 17, 2012 They all eat the same once grilled up. Link to comment Share on other sites More sharing options...
mwm5094 Posted March 17, 2012 Share Posted March 17, 2012 I just cut my finger trying to cut my springs. Ohhhhh Link to comment Share on other sites More sharing options...
scoobyscoodle Posted March 17, 2012 Share Posted March 17, 2012 How do we know OP is not trolling? I want pics of the springs he engineered. Link to comment Share on other sites More sharing options...
LosAngelesLGT Posted March 17, 2012 Share Posted March 17, 2012 Link to comment Share on other sites More sharing options...
ernisill Posted March 17, 2012 Share Posted March 17, 2012 shit i'll take a 335i xdrive twin turbo anyday, please? sorry know this is totally off topic but never ever buy one, trust me. had a 07 for 2 years before i just bought my lgt, biggest piece of shit i've ever owned. total money pit. do not recommend Link to comment Share on other sites More sharing options...
Spoonwacker Posted March 17, 2012 Share Posted March 17, 2012 sorry know this is totally off topic but never ever buy one, trust me. had a 07 for 2 years before i just bought my lgt, biggest piece of shit i've ever owned. total money pit. do not recommend Don't worry. We'll make sure that message gets to the right people, no matter where you post it. sorry...this forum practically blows goat nuts so im not always on here.Team Pony Express POSTED FROM MY COMPUTER USING A WEB BROWSER Link to comment Share on other sites More sharing options...
charlie_sheen Posted March 17, 2012 Share Posted March 17, 2012 i cant believe i'm just seeing this. its okay OP i cut my springs too. i dont know what all the fuss is about? just kidding i'm not a retard. Link to comment Share on other sites More sharing options...
RuskiTrombone Posted March 17, 2012 Share Posted March 17, 2012 Crazy what people do to save a little bit of money. Link to comment Share on other sites More sharing options...
charlie_sheen Posted March 18, 2012 Share Posted March 18, 2012 forrizzle. OP, i could have shipped you some h-techs for just 4 easy payments of $24.95 Link to comment Share on other sites More sharing options...
mwm5094 Posted March 18, 2012 Share Posted March 18, 2012 Who needs springs? Just run struts only. Link to comment Share on other sites More sharing options...
thestratomaster Posted March 18, 2012 Share Posted March 18, 2012 ...wow Link to comment Share on other sites More sharing options...
NSFW Posted March 19, 2012 Share Posted March 19, 2012 thanks ill search out this chart what struts/shocks u rockin? Click the 'wiki' link in the bar at the top of this page. Then click the 'Legacy' link. Then click the 'BL (2005-2009)' link. Then click the 'handling modifications' link. Incidentally, I compiled most of the tables on that page, back when I was wondering what parts to get. It's interesting to look at how much the front:rear ratios vary from manufacturer to manufacturer. That suggests to me that there's either a wide range of acceptable F:R ratios, or many manufacturers have no idea WTF they are doing. Link to comment Share on other sites More sharing options...
NSFW Posted March 19, 2012 Share Posted March 19, 2012 I am a structural engineer licensed in 6 states, and this diagram makes no sense to me. I am a professional data-structure architect, unlicensed in all 50 states, and that diagram makes no sense to me either. The part that really bothers me is that the 'cut' spring has a dimension callout next to it which states that it's 6" long - the same as the original spring - and yet if you look at the pixels it is clearly longer than the uncut spring. Whoever made that diagram clearly had one purpose in mind, and only one: to **** with the minds of complete strangers. Which is pretty awesome if you ask me. I am going to bookmark that picture, because it looks so persuasive from a distance. Next time people start arguing about spring rates, I'm going to lob that into the discussion like a hand grenade, and then I'm going to unsubscribe for a week. Then I'll check in to survey the damage. Link to comment Share on other sites More sharing options...
Cyclozene Posted March 19, 2012 Share Posted March 19, 2012 OP! Y U No here??? I'm curious for pictures! —Pirated Tapatalk app Link to comment Share on other sites More sharing options...
BAC5.2 Posted March 19, 2012 Share Posted March 19, 2012 I am a professional data-structure architect, unlicensed in all 50 states, and that diagram makes no sense to me either. The part that really bothers me is that the 'cut' spring has a dimension callout next to it which states that it's 6" long - the same as the original spring - and yet if you look at the pixels it is clearly longer than the uncut spring. Whoever made that diagram clearly had one purpose in mind, and only one: to **** with the minds of complete strangers. Which is pretty awesome if you ask me. I am going to bookmark that picture, because it looks so persuasive from a distance. Next time people start arguing about spring rates, I'm going to lob that into the discussion like a hand grenade, and then I'm going to unsubscribe for a week. Then I'll check in to survey the damage. I didn't even see the pic until now. Makes me If you cut springs, they get longer! [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
BigBlack-V Posted March 19, 2012 Share Posted March 19, 2012 i cut my Cobb springs this past weekend, i wanted more LOW like a VW yO !! I was 0. And I'm still a zero. Link to comment Share on other sites More sharing options...
Lardo420 Posted March 19, 2012 Share Posted March 19, 2012 did you put 205's on a 10" wide wheel too? Link to comment Share on other sites More sharing options...
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