D2 Coilovers?

[uslspct]

I've been looking at these as well since I will be doing a full suspension redo. I pretty sure I was set on Skunk2 springs and Nuespeed/Koni yellows but Granite has always raved about his setup, and some others too. For the price it seems like a win. Maybe someone will have the Neuspeed setup at the CT meet and then I can ride in theirs and yours(Granite) if you're going. Both seem to have great reviews. I would think a true matched coilover would be even better than the Neuspeed setup.
And I think I'm gonna seriously consider them for my Fit setup.

[azian21485]

Yes, in a sense you are right, I did not install an 8K spring in the rear BUT by increasing the preload you can sort of "imitate" the characteristics of an 8K spring but w/ a 7K spring. Also, I'm sure length of the spring, coil diameter, and other factors would determine how much preload is needed. By saying 1 inch, I feel more factors need to be evaluated before just throwing preload specs out there.

It was my estimation and I'm not saying I'm right but I can tell you this, even 5/16" increased preload made QUITE the difference

The only time preload will effect a vehicle's characteristics is when preload is greater than the load (In this case, your car) that is placed on it. Take a 500lb spring and preload it 1 inch. Place a 400lb load on it and the spring will not compress. Place a 501lb load on it and the spring will compress very slightly. Place a 1000lb load and the spring will compress 1 inch.

So what does this mean? Let's say you have a 1000lb/in spring on each corner of the car. You preload each by 1 inch. Each corner of your car weighs 500lbs. So when the car sits on the springs, the springs will not compress at all since they are exerting a 1000lb/in force upward while the car is only exerting a 500lb/in force downward. In fact, the springs will not move at all until it sees another 501lb/in force (From bumps in the road or load transfer when cornering). This is NOT a good setup because you basically have a car with no compliance until it sees a certain amount of force.

The reason I said you had to preload the rear springs by more than an inch was a very crude guesstimate. Using 500lb rear corner weights and a 500lb rear spring, you'd have to preload the rear springs by more than 1 inch to get "no compliance" characteristics. Other wise, preloading will not change anything (which is a good thing).

Edit: Please realize I am using linear rate springs as an example since I assume they use linear rate springs on d2 coilovers. If they are progressive rates, then yes preload will change your spring rates.

[cali-racer]

i have them on my cb7 right now, i love them!

edit: they're cheaper on honda-tech.com! i paid $785 shipped.

http://www.hondamarketplace.com/zerothread/1931708

[Granite CB7]

The only time preload will effect a vehicle's characteristics is when preload is greater than the load (In this case, your car) that is placed on it. Take a 500lb spring and preload it 1 inch. Place a 400lb load on it and the spring will not compress. Place a 501lb load on it and the spring will compress very slightly. Place a 1000lb load and the spring will compress 1 inch.

So what does this mean? Let's say you have a 1000lb/in spring on each corner of the car. You preload each by 1 inch. Each corner of your car weighs 500lbs. So when the car sits on the springs, the springs will not compress at all since they are exerting a 1000lb/in force upward while the car is only exerting a 500lb/in force downward. In fact, the springs will not move at all until it sees another 501lb/in force (From bumps in the road or load transfer when cornering). This is NOT a good setup because you basically have a car with no compliance until it sees a certain amount of force.

The reason I said you had to preload the rear springs by more than an inch was a very crude guesstimate. Using 500lb rear corner weights and a 500lb rear spring, you'd have to preload the rear springs by more than 1 inch to get "no compliance" characteristics. Other wise, preloading will not change anything (which is a good thing).

Edit: Please realize I am using linear rate springs as an example since I assume they use linear rate springs on d2 coilovers. If they are progressive rates, then yes preload will change your spring rates.

I respect your input alot, and honestly, you seem way more knowlegable on this topic than me, which I'm not striving to be a suspension know-it-all! I'm learning too, so please don't think I am arguing w/ you D2's have linear rates too BTW, which is a good thing for a full coilover

I'm just sort of confused about your #'s, which the preloading by an inch may be throwing me off. A 1000 lb/in spring does require 1000 lbs of force to compress it 1 inch, but any significant weight will compress the spring. It's not like it suddenly compresses 1 inch once 1000 lbs is applied. Even the 1000 lb/in spring w/ 1 inch of preload, w/ a load of 500 lbs, I feel it's still going to compress because it's all progressive up to the spring compressing its full inch.

I know this isn't technical at all, but I feel a linear rate spring w/ even a very small preload (like 1/4") will make the spring more "charged" because the spring will always want to go back to it's original state. Therefore, having the preload and an additional force, the spring will act like a stiffer spring w/ no preload.

[azian21485]

I know this isn't technical at all, but I feel a linear rate spring w/ even a very small preload (like 1/4") will make the spring more "charged" because the spring will always want to go back to it's original state. Therefore, having the preload and an additional force, the spring will act like a stiffer spring w/ no preload.

Preloading a spring does in fact "charge" it. If a 1000lb/in spring is preloaded 1 inch, the spring will be exerting 1000lb/in energy outward. Hooke's law states this.

Regarding preloading a 1000lb/in spring 1 inch and then placing a 500lb load on it. Preloading the spring will cause the spring to exert a 1000lb/in force up. Placing a 500lb weight is not enough downward force to overcome the 1000lb/in upward force. Draw a free body diagram =) Once the load exerts 1000lbs, the spring will act just as normally as it would have with no preload.

This comes back to your car. If the load (your car) exerts the spring's preload, the spring will act normal. If the load doesn't exceed spring preload, the spring will not compress. In simple terms, 99% of the time you will not be able to preload the spring enough (i.e. preload greater than corner weight of car) to change its characteristics.

I had a good link in the past when trying to understand this myself. I'll try to dig it up.

[91h22cb7lx]

i have d2's but i blew my motor before i could put em on, bought another accord a few weeks ago and they will be going on this summer. my buddy had both d2's and function and forms.. personally i liked the f2's better because they actually click when you change the settings and it felt like it had more adjustability with less settings, but my buddy did pretty good in autox in his eg with d2's.