no problem.

As stated on this website http://www.theautochannel.com/news/2...02/182931.html

"They began by significantly increasing the spring rates, and SRT-6 Coupe and Roadster models are tuned differently, to their own unique characteristics. The Coupe's spring rates are 451 lb./in. in the front and 480 lb./in. in the rear, while the Roadster's are 434 lb./in. in the front and 451 lb./in. in the rear, compared to 303 lb./in. front and 337 lb./in. rear on the base Crossfire Coupe and Roadster models."

Now our springs look the exact same with one coil cut as they would stock. It will sit the same way it would from the factory.

 

ppro - your right - and yet so wrong.

1) Anytime you lower a car, no matter the method used - lowering springs, cut springs, lowering cups, etc... you will disrupt the camber - I totally agree - seen this on a few Crossfires, with cut springs (mine) and with lowering springs (Andrews) - etc...

2) The factory Crossfire springs don't look anything like stock or lowering spring pictured above - I went over to a forum members house who had replaced his springs with Eibach and looked at his factory springs before I even started my mod.

In the picture below the stock SRT6 rear springs are trimmed at the top and left factory at the bottom. Even before cut they look like the "cut stock spring" on both sides pictured in your example.

I respect what you are saying - and 9 times out of 10 you would be right and be offering good advise. I too, thought that if the factory springs looked like ones your example, there was no way I would trim them.

Take an hour out of your day this weekend and pull one of the rear springs - and take a look.

 

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHAHHAHAHAHAHAHHAH AHA I AM WATCHING OVERHAULING AS WE SPEAK IT IS THE BOSS 302 EPOSIDE CHIP FOOSE PUT THE CAR ON THE GROUND DIDNT LIKE HOW IT LOOKED JACKED IT BACK UP PULLED THE SPRINGS OFF AND CUT OFF 3/4 OF A COIL....... call him lol

 

TV. I bet if I call him, he'll tell me that he's getting the ride height figured out and then he's going to have some springs made up to give him that but with the right spring rate etc.

 

I do want to thank ppro for providing some VERY good drawings and information on the subject.

But I'm still disagreeing with the concept that "cutting springs is wrong". It's not that black and white.

I agree with Brianbrave when he says ppro is so right but also so wrong. Read Herb Adams. It's THAT simple.

 

Make sure you record it for us.

 

Finally, something we can work with. THANKS!

OK, first - the point I keep trying to make is not about SRT6 factory vs Eibach. That's not the point. The Eibach Pro is a progressive rate spring but I digress.

Look at your numbers for the SRT Coupe. Let's just take the front for example. 451 lb/in. OK?

So it takes 451 pounds of force to compress the spring one inch. So it takes 902 pounds of force to compress the spring two inches. Make sense?

Now, let's cut off the part of the spring that represents that first inch of compression and put the springs back on the car.

Now the car is an inch lower. Good so far? OK.

So let's hit the suspension with 902 pounds of force upward. How far is the suspension going to move? If you're right that they're not progressive springs, (and I am not sure you are but will play along) then the suspension will still compress 2 inches. Make sense? Sure.

But here's the kicker - you cut an inch of compression OFF the springs so the effect is the same as a 3 inch compression (your two inches of compression and the missing inch you cut off). OK so maybe that's no big deal you say? Well the car has about 5 inches of ground clearance. I have no idea what the range of suspension travel is, but I bet you're getting close to the limit when you compress 3 inches on a car that has only 5 inches of clearance overall.

So the point is, with the cut spring, you're going to have less travel for a given force before you bottom out. Not good.

The lowering springs have the same inch taken out but the pounds required for an inch of travel is raised to compensate so that you can take the same force on the shorter spring and not bottom out any sooner than a stock spring.

So the lowering spring has a lb/in rating higher than the stock spring it replaces in order to provide the same effective spring rate at the lower ride-height.

The picture is pretty dismal for a normally aspirated coupe isn't it? The spring is rated at 303 on the front. That means cutting an inch of compression off the spring is really going to have an effect.

I am buried with real work so I don't know when I will ever get to pull a wheel but I imagine it's easy to measure total suspension travel and give before and after effective spring rates based on that. The thing is, to me it's academic.

Does anyone have the lbs/in for Eibach or for that matter H&R? The math is easy from there. Eibach says their progressive rate spring doesn't have a lbs/in rating but rather a load/deflection characteristic only available to partners.

Eibach also says:

 

Don't forget that Chip Foose is a designer not a suspension engineer. His cars are beautiful but I don't know that everything he does is necessarily both pretty and good for handling.

 

ppro, listen:

This is very, very incorrect. First of all, the length of the spring is not the correct measurement to use when cutting springs. When you "cut 1 inch off a spring" that says nothing about:

1. The drop of the car.
2. The change in the spring rate of the spring.

This is because the spring is always inboard of the wheel and one must take into account suspension geometry when equating a cut spring with lowering height.

What one must actually take into account is the number of total coils from top to bottom in the spring. This is because the spring rate of a spring is a function of spring diameter, wire diameter, wire material and number of coils.

You also make some incorrect assumptions:

1. The spring rate of a cut spring is NOT the same as an uncut spring
Let's say that the 451 lb/inch spring of the crossfire is due to a 0.57" wire diameter, 4" spring OD and 8 coils from top to bottom. Let's say that we cut off a "half coil" from the spring to lower the car by 1 inch. The half coil cut increases the spring rate to 490 lb/inch. Therefore, although the car loses 1" of travel, the spring rate has increased by 10%.

2. The suspension of the automobile does not "bottom out" when the spring is fully compressed
A coil spring suspension has something called a "bumpstop". This is a very high spring-rate urethane or foam rubber compound with an extraordinarily high rising rate. Under NO circumstances shall a suspension, regardless of the kind of springs that are involved, ever get to a point where it's just the tire solidly connected to the chassis. This is because the bumpstops are designed to provide an aggressive amount of damping BEFORE the springs become fully compressed. The FIRST thing that the suspension hits on a hard bump is the bump stop. The bump stop shoots the spring rate from the spring's 451 lb/in to something on the order of 650 lb/in on up to 850 lb/in on full compression.

Like I said: Cut springs are what they are. They are not evil or stupid. They simply are slightly shorter springs with a higher spring rate and will use the bump stops more often on aggressive bumps.

 

+1 on several of these posts.

Don’t you guys know that our cars are exquisitely engineered and simply cannot be improved upon?

 

I had written a blow-by-blow counter-response to this but in the end the magnitude of your misunderstanding was so enormous I just decided it wasn't worth responding to except to say that you really didn't understand what I wrote, and seem to be arguing issues that aren't even being debated. Frankly coming from you, this is a surprise because until this post, I really thought you understood this stuff. I guess I was wrong. Nothing personal but holy crap, you missed the point!

 

Dude!

Just let all go....Like the river's current chasing to it's end....taking the leaves of autumn with it as it meanders around the bends and slowly passes the families as they bask in the sun and enjoy their picnic's from the banks.....listening to soothing gurgles of the waters surface singing it's happy song.....unaware of the drug dealer who was whacked that morning and tied down with bricks and tossed into it's secret depths......or the fish and other river creatures who are now eating his eyes and other soft tissue.....

Just let it all go and be at peace with your Crossfire and the Forum.......

 

and you wanted to know WHY I wouldn't invite my engineering buddies into this discussion...LOL...all this to prove who is right...what is right is what the owner wants to do and is satisfied with... it will not matter in a car this light...we have shortened frames on semi tractors...cut springs on them, added lift axles, drilled frames for the axles...always taking into consideration the safety and performance of what we were doing...hell, the srt roadster's springs are too stiff now...for most people...I want them stiffer...and will add konis to the equation as well...those of us motor heads will do as we please....and difference you talk about will be unnoticeable...because the springs are built beyond the specs required for the job they have to do, as most truck springs are...spend some time in a REAL shop sonny, then get back to me...this is a ridiculous discussion now...its just about whos right and whos wrong...and in the end you are both right...but the springs will still be more than strong enough to do the job they need to do....

 

OleDoc,

I love your response!

There are "Old School" engineers (ones who work on the plant floor) and there are "New School" engineers (those who wave the Bible* in the face of years of hard-earned experience). And will do so just to educate the unwashed masses, whether they want to learn or not.

PPro, if you want to be completely shocked and sickened-go watch Lampson and Co.** perform a heavy lift. You'll see things that will send you screaming into the night.
Just don't try to tell these boy how to "do it right"-they get even touchier than you!

* Standard Handbook for Mechanical Engineers
** http://www.lampsoncrane.com/

As Ole told Lena "Don't try to teach Grandma how to suck eggs-she's been sucking eggs a long time and knows how".

 

To those who think they're fine cutting springs, I simply say you're clueless.

Don't confuse putting the info up with practical inexperience.

Don't confuse the ability to understand with the inability to turn a wrench.

I always find it amusing to see how the ignorant use brute force to try and defend themselves.

I refer to my first post where I predicted exactly the chain of events we have witnessed here. A bunch of young whipper-snappers and old farts blowing a lot of smoke about something they know little or nothing.

So we have truck drivers, spelling bee drop outs, wanna-be ricers, and suburban garage fourth-tier aftermaket parts resellers pretending to know something and defending ghetto mods with school-boy taunts. Maybe I should throw "poseur" in for free.

The weight limit of the Crossfire is 400 pounds of additional stuff. Go ahead and cut your springs, then jump in with another person. Even if the two of you weight about 150 pounds each, you've only got 100 pounds of capacity left. Toss a couple travel cases, some accessories and a fart can in, and you should be pretty much sitting dead-axle. You might even want to go online and order a nice

logo to stick on the back in place of the Chrysler wing.


It ought to be a pretty picture, you and your friend going around that Montana washboard curve at 140 mph that you're so fond of. Well I guess Darwin was right. And that's why they give awards in his name.

Cut on, your cartoon, truck-driver, web-logic will never let you down!

I bet not one of you defending the notion of cutting springs even read or understand the sound explanation provide to educate. What was I thinking. Half of you haven't even read the manual.

Cave men.

 

PPRO i think your just frustrated with your life... find a girlfreind our something there are alot of date sites out there. maybe you can win them with your profound spelling an punctuation.. ? maybe not.... at any rate not spring rate maybe you just need to stop hitting the books and step into the real world and get your hands dirty. maybe your the type that PAYS someone to work on your car. actually my wife does own a 2008 honda accord coupe.. thanks for the long winded discusion that did'nt prove anything..god bless......

 

 

crickets.......................................... .........

 

and if you ever spend anytime in a REAL spring shop, you would crap your pants...throw a little black paint on her, she's done...do you really think manufacturers check each and every spring they ship out, and does that engineering mind think that each spring is perfect? No, sonny...they work within tolerances...and that is simply what we are talking about...I could fit my roadster springs on a much heavier car and they would work fine...they are actually over-engineered for the job at hand, much like you are...with that attitude, you won't last long in the real world...cause some old guy like me would fire you @ss...for not having something called "common sense"....or practicality...but that does come with experience doesn't it...you have a nice day....and I did share this w/ my mechanical engineering buddy, whom many met at Woodward last August...he just laughed...he just modded out a Soltice....but, what we he know w/ his 35 yrs of experience...thanks...Max...you just had to make me post 1 more time...

 

Just like everything else you've said you're way off. Well no, I don't doubt for a minute that your wife has a Honda...

I have a wife, she's beautiful inside and out, and two smart kids who have been brainwashed into believing that cutting springs is bad by their dad - even had one of them do the math - of course he complained that it was too easy and was taking away from his physics homework (he's in sixth-grade). We have a a great life, no complaints - we're heathly, warm, and love each other. The rest is gravy.

Hitting the books? What's wrong with that? When deciding to do something to improve the performance of a car, what says that the only way to learn something is go to a ricer web site and hear people describe ghetto mods? I learned a long time ago that research is important if you want to do something on an informed basis. One opinion isn't enough to prove a given approach is the right approach. (So don't just listen to me, go do your own research) Hitting the books is a way to

• find out what options exist,
• what the pro's and con's are,
• and in the end, determine if any of the options will work for the task at hand.

And gee, if you don't find options, then you do some more research and make one.

If you follow a link (or two) (or three) you can find a long history of things I have done to my vehicles - of course that's just the history since 2000 when I started recording it. There are pictures so it's pretty easy to follow along.

I don't have online records of the work done from about 1977 when I started working on cars, until 2000 when I started documenting what I was doing. Those things include four frame-up restorations (my hands, not the checkbook), six, bare metal paint jobs, suspension mods on several cars (no spring cutting...), engine rebuilds, body work, upholstery, the works. My hands. My tools. My time. The only tool I don't have in my garage is a wheel mount/balance machine. Maybe someday...

So don't presume you know anything about me, my experience, or my life. Clearly you don't. You probably haven't even been alive as long as I have been working on cars.

Here we have two basic options:

- Cut springs
- buy engineered suspension components

Either way they need to be installed. Do it yourself or pay somebody - it makes no difference to me. I'd do it myself because I like to, I have the tools, and I can.

The pro's and cons?

Cut springs - Pro's
- cheap
- instant gratification
- a caveman can do it
- car looks good instantly

Engineered Suspension Components - Pro's
- a caveman can do it
- car looks good instantly
- performance improvements in suspension (or no performance degradation at the least)
- can go back to stock for no additional cost (except time)

And the Cons...

Cut Springs - Cons
- reduced suspension travel
- reduced weight capacity
- increased risk of transfer of force to chassis and suspension components
- reduced performance of suspension
- increased risk of spring escaping from mount
- must replace stock springs if cut spring experiment doesn't work out (Cost)

Engineered Suspension Components - Cons
- increased cost over cut springs

So in the end it's my opinion that

• cutting springs doesn't in the long run save money (because if you keep the car long enough and drive it hard enough, the suspension will prove unsatisfactory and to go back costs as much as engineered suspension components, and that's assuming nothing but the springs need attention. There's also the cost of the prematurely worn-out tires, damaged suspension and chassis components, and the time to do the job over).
• it degrades performance, which is generally the reason one would make suspension modifications in the first place.
• it creates potential safety issues.

All in the name of "being a man" and saving $250? Please.