StevoVIII

megan over tein?

you sir are nuts.

have installed MANY megan racing products, NEVER been impressed (exhaust, Headers, Springs, Various other suspension components)

Solarian

The Megans are actually Apexi N1 coils, re-branded. Made in the same little factory in China, by the same under paid child labour lol. They're not a bad coil at all. Not sure how they compare to the Tein SS however.

JohnEd

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MDEEZY,

Spring rate is drastically affected by a number of things besides the "weight" on that corner. For example: Tilt or lean of the spring. A 45 degree tilt inboard will require a spring that is twice as strong as one in the same position mounted in the vertical.(I think). How close to the center of the tire the spring attaches. How long the lower control arm is as a ratio to the attach points.

An engineer will come up with a hole p pot full of additional stuff.

I am not an expert here and I will gladly bow to informed opinion. High School physics explains this spring rate concept. That was the most useful course I have ever taken and I have 4 degrees. Degrees don't mean all that much, please understand. Just perspective. I am sure that anybody that messes with cars will benefit far in excess to the time spent in covering that basic course and that is an expert opinion.

Thank you for your post

John

MDeezy

Good post john.

Very informative. I see your perspective on the strength of the spring needed based on the forces created including lateral. With your post in mind an 18k/10k spring rate would sound reasonable given an (approxx) curb weight of 3500 for the SC. But a stiff spring isn’t the only component to maintaining a smooth ride. The shock/strut itself will assist also with its dampening. A softer spring could be used as long as the damepening is adjusted to compensate.

This spring rate is probably normal for most to all coilovers for the SC. I come from coilovers for my current car (96 Maxima) and have really only seen spring rates of 9/7 9/6 I think 11k/10k and those were racing coil overs. But seeing the tegra and civic with 12k/xxkg spring rates is what threw me off.

Seeing the spring rates for the sc from other manufactures leads me to believe the 18k/10k is a normal durable rate. Ksport has the same spring rates along with a few other places I saw.

Solarian

The tilt or lean you're speaking of is generally very small, since it is a very bad idea to have it be larger, especially in a mac strut system as employed on over 90% of cars in the front. Also, it is within the same angle range for most vehicles, so it totally negates that. The tire bit is not really related to how your car came from the factory, but rather size and offset wheels you have on your specific vehicle, and the lower control arm length is also not very varied generally.
The purpose of a performance suspension is to keep the car as flat as possible, and spring rates are varied front to back to compensate for weight distribution. If a vehicle carries more weight up front, it needs a higher spring stiffness to keep the same displacement as the rear. It's related quite simply through hooke's law, where force is equal to stiffness multiplied by displacement. The force being different on front and rear, the stiffness must also be different to maintain the same displacement. If you want I could go into more detail.

JohnEd

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Solarian,

OK....OK....I give...Hooke's law? Please, don't go on. Engineer, right?

Kidding here.

Mac seems to be everywhere, you are right. Except out Lexus SC's. "A" arms like the go fast racers. Mac is cheaper to build but not a better suspension system from a performance perspective. My point was that there are more things in play than weight and the other post proves my point, sort of. A civic with higher spring rates than a 4 K lb Nissan Maxima?

I think it is complicated enuff as it is but you start putting in numbers and everybody's eyes start to glaze over. Unless they are trying to by/select a spring, of course.

Thanks for your post.

John

visi0n

no, the LOW model Apex-i coilovers are made in taiwan or china. not the N1 line.

plus, it doesn't matter, megan, D2, KSport, etc they all have different valving. Megan by far is the worst.

MDeezy

please do . . .


~2900lbs to be specific . . .

JohnEd

iTrader: (1)

MDeezy,

Up till the 60's all sports cars had a harsh ride. It was the nature of the beast. Lotus cars came out with a really plush ride and lots of travel to queer the works. Their theory was, as you stated, use the shock for more control and they had complex dampening. I recall that being discussed in an article about what company did what to the industry and Lotus was be lauded for having introduced a decent ride to sports cars and making a champion handling car. Of course I was "very" young back then and only remember the gist of the article. Between my TR4A and my TR3 I lost a kidney and two teeth. Those defined rough ride.

My favorite all time shock for my daily drivers has always been Bilstein. They have demonstrated an ability to anticipate what the road will do so well that I have looked for where to install the replacement batteries for the computer that must be in there.

I agree with you completely.

John

MikeFD3S

*whistles* I still don't understand why so many tuners subscribe to the whole stiffer is better thing on a street car-- something they take to the track no more than 2-3 times a year.

I think a lot of the people who are buying these suspensions (Megan, D2, etc) attest to their "great ride" due to "purchase justification" -- that is, the natural tendency for one to justify one's own expenditures. Kind of like the butt dyno...completely unscientific, and in most cases, completely misleading as to the actual results/effectiveness you are getting.

Here's some good reading on how shock absorbers (they actually work as spring dampers) and springs actually function.

http://www.turnfast.com/tech_handlin..._springs.shtml
http://www.turnfast.com/tech_handlin...g_shocks.shtml

Stiffer isn't better in most cases...

There was also this really great article from an E30 M3 owner regarding lowering suspsensions, but I lost the link. If someone knows what I'm talking about, please post it! It was a very long, but super informative rundown on spring rates, weight distr., etc.

I used to work at a Japanese aftermarket manufacturer (of reputable quality), and the majority of these dampers from china are utter garbage. Crap seals, cut corners on build quality, really low quality springs. The actual cost of them is ridiculously low (think 30-40%) compared to the MSRP. We got bombarded almost daily by these companies in Taiwan or various parts of China to outsource with them, but after reviewing a few out of curiousity, they are all garbage. I could go on, but ahh fuggedaboutit.

MDeezy

I Agree stiffer and/or lower isn’t always better. Some will slam their car thinking it will corner better, but there is a certain ride height where the car will operate great, but lower or higher than that will have the inverse effect. Too stiff of a spring can result in lot of under or oversteer depending on how the coilovers are adjusted. I feel that most who modify their car(s) probably don’t track it that much. A high spring rate on springs that will only be seeing the highway and city streets is not a the greatest move. When one hits the bumps in the road, that is when those stiff springs will show their downside. On another note this is where coilovers have their advantage, more or less pre-load in conjunction with dampening adjustments can make what was a bumpy uncomfortable ride, into a smooth tolerable ride. The stiffer the spring the harder it might be to achieve that’s smooth but firm suspension setup.

Coming back, it seems as if to a degree a higher spring rate is needed for a heavier car. How high of spring rate a person desires it up to the person and their plans for them.

Ksport coilovers :18k/9k
Stance: 18k/10k
Tein 14k/8k

Still looking up more for the sc300, haven’t touched any supra coilvers but seems as if they are in teens for the front and rear close to teens.

In response to the quality of them, I’ll search for reviews, but I know the Ksports for the Nissan Maxima, work great but a good few are having some quality problems, blown after a month of use, leaky piston, etc.


great information.

JohnEd

iTrader: (1)

MikeFD3S,

The link you posted for handling info is the best pocket of information I have seen in a long long time. Thank you for adding this to my data resourse. I learned that a few things I have believed longer than you have been on planet earth (probably) were false, still more needed tweeked.

Thank you very much for taking the time to help me.

John

EVERYBODY TAKE A LOOK.....PLEASE

Solarian

Wow, thanks for the great response guys, people here are a lot more civilized than at a certain 240sx forum that shall remain nameless.
JohnEd- Yea, lol, I'm an engineer, is it that obvious?
And you're quite correct on the stiffer springs and lowering. It is NOT always the best way to go. Overly stiff springs on a street car could wreak some serious mayhem. There are certain ideal conditions that race cars are set up for, and nothing even close to them exists on the street. Stiffer is better, ONLY applies if you're on a racetrack, with perfectly smooth pavement, and have racing slicks on your car. In city driving conditions, your stiff suspension and heavy damping will cause your car to not respond properly to all the bumps and potholes, and could even become dangerous. One half-decent solution to this, is coilovers with helper springs, which are a spring with a much lower stiffness, designed to absorb the bumps and keep your wheel in contact with the pavement.
Another issue is the lowering, when you lower your car, you alter the suspension geometry of it, reducing the allowed suspension travel, and often causing your car to bottom out, since it's already so low, the suspension cannot move anymore. There are ways to correct this, how I'm dealing with this on my 240SX track car, is by creating custom uprights from sheet metal (aluminum is just too damn pricey), so that the mounting points are displaced by the exact same amount I want to lower my car, keeping factory geometry. I don't intend to do this with the SC however, since I don't intend to ever race the car, and it isn't nearly as important to me how it would handle when being pushed hard.

JohnEd

iTrader: (1)

Solar,

YES! To me.

Nice post. Hope to hear more from you in the future.

John