Single leaf rear springs. (longish post)

[dbrick]

Greg,
Unless I'm having a logic breakdown, the blocks should lower the car by their total thickness. ie: 1 inch block lowers the car 1 inch. I can't see any way it would be a percentage of the blocks thickness, as it is directly over the axle. Unless the block is significantly longer then the spring mounting pad, and you are locking out part of the spring by flattening it as you tighten the block, it should lower the car by it's full thickness.

[Gregs672000]

Greg,
You don't really want to go any lower than stock ride height (perhaps just a hair lower, half the distance to the comp springs). The comp springs move the roll center too low. My guess is that the KYB dampers don't have enough damping to really control those springs. I find them bouncy on stock setups.

Will

So are you saying that the rear should be a bit higher than the front? I have comp springs up front, and what I want to do is bring the rear to the same height as the front (frame to be 4.5 inches off the ground), or at least I thought that was correct! I also understand that your car is primarly used for autox and you want to get the absolute most out of it for that environment... I want a combo, where I like how it looks but also want good street handling and a decent ride. I appreciate your input and knowledge. What is the preferred shock? I've heard people doing custom valving etc., but don't think I want to or need to go that far. Would a set of Konis (part number?) as they are do me for the street, or be too harsh? I like firm but not stupid jarring. I really like the Gas-Adjusts over the GR-2s... maybe I'll like the Konis even better?

...the blocks should lower the car by their total thickness. ie: 1 inch block lowers the car 1 inch. Unless the block is significantly longer then the spring mounting pad, and you are locking out part of the spring by flattening it as you tighten the block, it should lower the car by it's full thickness.

Thanks, I agree. I think I just didn't tighten things enough to get an accurate measurement (surprising how much effort/turns it took to get the U bolts to 50lbs of torque, and I am sure it compressed things a lot more). The blocks only hang over maybe a 1/2 inch each side so I highly doubt that is an issue. Looks like I will have a set of 1 inch blocks available soon... I just LOVE doing things twice.

[Gregs672000]

I see that there has been a lot of discussion over the years on shocks... sounds like some feel the gas-adjusts in the rear are not the way to go with comp springs. May look into Konis, as I like the firm ride but hate being jarred... maybe with the more compliant composit mono-spring it will work well.

[SLOroadster]

I run my Konis full soft both front and rear. As for your front springs, do you have the Nissan comps or some one else's? Ideally, you want the front lower control arms to be horizontal to the ground to get the lowest possible roll center without it going below ground (bad, bad, bad! Creates all sorts of issues, none of which are good.) You also want just a touch of forward rake to the car, the rear being just a little higher. This gives you a good roll axis (the invisible line between the rear roll center and the front roll center. This is the axis that the pivots around in a corner. The ideal roll center for most cars (not just Roadsters) in the front is 2-5 inches above ground and the rear anywhere from 4-10 inches. With the back end higher than the front the car will transfer more weight to the front, making it more likely to understeer at the limit. The closer you can get the roll axis (always below the center of gravity) to the mass axis (the axis that runs between the front and rear centers of gravity) The better. If the mass axis slopes upward toward the front, it will tend to understeer, if it slopes down toward the front it will tend to oversteer. I haven't taken the time to sit down and plot all of these points out on a roadster so I can't give you the exact height you want things to be. The quick easy way to tell your front end is right is if the lower control arms are level with the ground.

If you can get your roll centers in the right spot, you can reduce the roll couple and effectively lower the center of gravity. This is something that I have been trying to get sorted since my car is tail happy both on the track and on the autoX course. You won't make the ride more harsh by keeping the rear end high. I need to bring the back end back down some more. It will now push into the corner and oversteer out unless I run a full tank of gas (changes weight distribution and ride height since it compresses the back end). With the full tank of fuel, the car feels much better

If you look in the racing forum section find the tread "Nor Cal UFO AutoX event #9" and look at the pictures. There are two of them where I am lifting the passenger rear wheel through a corner. The car is very flat through the corners however. (Unless the rear tire is 4 inches in the air.)

Will

[Gregs672000]

I have the old comp front springs on the car. The control arms are horizontal. I think I'm gonna go ahead and drop the rear the other 1/2 inch and see how it is. That will mean the car is the same height front and rear, at least according to the frame and where I am measuring it. The rear is still gonna be up quite a bit higher than the car used to set with the de-arched comp springs. I think the rear of the car may have been an inch lower than the front.

[Samuel_SRR311]

Rear Springs Purchased $29 each
Springs Re Rolled $75 each
Bushes Made $10 set

Now to fit them and see if all this hype is true

[notoptoy]

Rear Springs Purchased $29 each
Springs Re Rolled $75 each
Bushes Made $10 set

Now to fit them and see if all this hype is true

Exactly which rear springs did you purchase???

[Samuel_SRR311]

The springs are from a 1984 Volvo 360 GLT

it seems thats the joy of living in Australia we have these cars

[dbrick]

The springs are from a 1984 Volvo 360 GLT

it seems thats the joy of living in Australia we have these cars

So how much is shipping to the USA for a few sets I can trade for Electronic Ignition distributors

[Samuel_SRR311]

Hmm interesting is it for a U20

What I could do is make sure that these fit ok and do the job then once thats done and I am happy get another set made up and send them to you so it will be about $240 AUD without bushes + postage

Springs $ 60 inc GST
R-Roll $176 inc GST

Thats if I can find them at that wrecker.

[zippy67roadster]

Hmm interesting is it for a U20

What I could do is make sure that these fit ok and do the job then once thats done and I am happy get another set made up and send them to you so it will be about $240 AUD without bushes + postage

Springs $ 60 inc GST
R-Roll $176 inc GST

Thats if I can find them at that wrecker.

I would be interested for that price! What do you think shipping will be?

[SLOroadster]

Shipping on them is going to be about $400, ask me how I know.

Will

[Samuel_SRR311]

Maybe I will have to go and get a quote from the post office what would be the area of the states I would be sending them to.

[dbrick]

Maybe I will have to go and get a quote from the post office what would be the area of the states I would be sending them to.

It's Kenilworth New Jersey, 07033 worth getting a quote.

[zippy67roadster]

Maybe I will have to go and get a quote from the post office what would be the area of the states I would be sending them to.

Las Vegas Nevada 89129, unless you just want to pack them in a suitcase and bring them personally!