Cutting Coils: Let the hate flow....

[continuecrushing]

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but seriously, there are many many very affordable ways to drop the car

[Chad_W]

I hear what your saying, but we're being speculative here and that's why I'm looking for a calculator.

Stock BRZ rates are 153/195

Swift Sport Springs Drop 1" and are 212/252

If I calculate the stock .5" cut rates and come up with something like 185/225 it may be a reasonable experiment. If I come up with 158/200 I could expect to spend a lot of time on my bump stops.

[Chad_W]

Originally Posted by Shutter

Next Thread: Baby stomping!


but seriously, there are many many very affordable ways to drop the car

Like many things in life there are handful of good options and bucket load of bad ones.

I am genuinely interested in exploring the topic a little a further and I hope anyone who checks in here is on the same page. There are tons of myths and anecdotes about how horrible the idea is, but ultimately there is a right and wrong way to do it. The point of this thread is to see if cutting the correctly measured amount can create an acceptable spring rate for my goals.

I'm sure everybody knows a kid who dropped his 93 accord 4" on the stock struts by cutting the coils and had a bad time.

[Gunman]

Originally Posted by go_a_way1

cutting springs also weakens them near the cut and makes them prone to snap near the cut

The cut is at the very end, and the coil is "dead" there. I'm not sure how a properly cut coil would fail. Heated yes, that weakens the spring by annealing it, but cutting only heats the very end, if that. I suppose if you cut it really slow, with a torch, you could cause it to anneal farther up the winding, but in general terms, properly cutting a coil is perfectly safe.

fwiw Herb Adam's even suggests it in his book, "Chassis Engineering".

[go_a_way1]

Originally Posted by Gunman

The cut is at the very end, and the coil is "dead" there. I'm not sure how a properly cut coil would fail. Heated yes, that weakens the spring by annealing it, but cutting only heats the very end, if that. I suppose if you cut it really slow, with a torch, you could cause it to anneal farther up the winding, but in general terms, properly cutting a coil is perfectly safe.

fwiw Herb Adam's even suggests it in his book, "Chassis Engineering".

To be totally honest I am no expert in the field, I was always taught cutting spring weakens them and thats the only logical way they could be weakened, but your probably right that at the ends its a "dead zone"

Question for OP how will the spring sit on the perch once they are cut? I thought they do a near full rotation at the base/top before beginning to coil up/down??

[Gunman]

Originally Posted by go_a_way1

To be totally honest I am no expert in the field, I was always taught cutting spring weakens them and thats the only logical way they could be weakened, but your probably right that at the ends its a "dead zone"

Question for OP how will the spring sit on the perch once they are cut? I thought they do a near full rotation at the base/top before beginning to coil up/down??

Funny, in that case you heat the end, and form it back to a full rotation at the end, but again, that is all dead coil.

From Herb's book:

[go_a_way1]

Originally Posted by Gunman

Funny, in that case you heat the end, and form it back to a full rotation at the end, but again, that is all dead coil.

From Herb's book:

Neat. This herb guy sounds like a good time hahaha!

[Gunman]

Originally Posted by go_a_way1

Neat. This herb guy sounds like a good time hahaha!

I've never met him, but I bet he has cool stories!

http://blog.caranddriver.com/50-year...sa-sports-car/

If you don’t know who Herb Adams is, here’s the recap: He’s the legendary Pontiac engineer/head of special projects that created the GTO Judge package, the ’69 Trans Am, and the limited-production SD-455 engine, among other cool projects. Two oil embargoes and the advent of emissions restrictions then ushered in the dark ages of performance; Herb had left GM in 1973 to start VSE (Very Special Equipment), cranking out hard-core aftermarket suspension pieces for libidinous car enthusiasts. His go-faster business has evolved into producing Cobra replicas and kit cars from his latest venture, Passion Motors, headquartered in Sterling Heights, Michigan.

[go_a_way1]

Originally Posted by Gunman

I've never met him, but I bet he has cool stories!

http://blog.caranddriver.com/50-year...sa-sports-car/

Yup he sounds like my kinda guy hahahaha!

[pushrod]

Made this little article like 5-7 years ago about this very subject. I haven't verified it since, but it's probably not too far off from reality:

http://craig.backfire.ca/pages/autos/cutting-springs

[JEDI]

Originally Posted by Gunman

The cut is at the very end, and the coil is "dead" there. I'm not sure how a properly cut coil would fail. Heated yes, that weakens the spring by annealing it, but cutting only heats the very end, if that. I suppose if you cut it really slow, with a torch, you could cause it to anneal farther up the winding, but in general terms, properly cutting a coil is perfectly safe.

fwiw Herb Adam's even suggests it in his book, "Chassis Engineering".

I'm sure this was a great book to have back in 1992. A lot has changed since then such as, research, tech, new manufacturing techniques, and materials just to name a few. Seems a little outdated for our application IMO. Back then we cut or heated springs because it was one of the few options we had in order to lower our cars, now we have tons of options, affordable options. Over the years I've heard "springs are springs and they all come from the same German manufacturer no matter what brand of spring you buy". How much, if any truth to that I cant say. CUT EM, Take pics, let us know how it goes, its your car.

[Gunman]

Just for the heck of it, here is Paul Haney's article on springs. Good info, and math, if you want to crunch numbers.

http://insideracingtechnology.com/eibach1.htm

[MrDinkleman]

Originally Posted by JEDI

I'm sure this was a great book to have back in 1992. A lot has changed since then such as, research, tech, new manufacturing techniques, and materials just to name a few. Seems a little outdated for our application IMO. Back then we cut or heated springs because it was one of the few options we had in order to lower our cars, now we have tons of options, affordable options. Over the years I've heard "springs are springs and they all come from the same German manufacturer no matter what brand of spring you buy". How much, if any truth to that I cant say. CUT EM, Take pics, let us know how it goes, its your car.

I agree. Although there is nothing wrong with cutting your stock springs, you should look at all the options available to you. In the end, if you factor in the value of your time, you will probably come out ahead buying the correct spring kit. As Jedi said, back in the day, it was a necessity to cut springs for a street car. The only other option was to adapt full-on race Koni coilovers and custom springs that could cost around $1,000 EACH and that is in 1970's dollars.

[Ashikabi]

I think since the spring is progressive, cutting the spring will change it's rate in a way only toyota(or Subaru) can know. Letting springs are dirt cheap, there is really no reason not to just get them. They also won't severely devalue the car. Have fun trying to sell it with "chopped"springs. If you can't afford $300 for springs, you shouldn't be making payments on a 3 year old car.

Additionally I asked Stance once about increasing preload on my springs instead of getting a stiffer set of springs and they told me it would have unforeseeable affects on the spring rate