I gotta replace these 246,000 mile springs with something new this summer; between the Eibach Proline and Sportline, I'm leaning more towards Sportlines. I found a message (only ONE!) on here that said the Sportlines were linear, it'd be nice to hear this is true from a few other people.

I'm not too interested in a smooth ride; that's why I've ruled out the Pro kit. I'd rather not have my car feel like a boat when I'm driving slowly!

 

Sounds more like a problem with the shocks if it rides like a boat. The prokit doesn't ride soft, infact I think it's more stiff than the sportline. It might have just been the fact that one was with stock shocks, still it was about the same.

 

The Pro kit is more stiff? No offense, but are you sure? I thought the Pro kit was for someone who didn't want a rough ride.

 

Both are progressive rate springs. The pro kit is a smaller drop, so it rides a little better. Reason being, the final drop of the car does not compress the shocks/struts as much as the sportlines, thus giving them more room to extend their full length. The sportlines drop the car a little more, in effect, squishing the shocks/struts a bit more making the ride a little harsher (giving them less room to move). You can counteract this in the front with an aftermarket set of strut mounts (HMS mounts for example) with a raised top. Even though the car is lowered, the extra traveled allowed by a strut mount with the raised top will allow the strut to extend the full length (well thats the theory anyway). All of this considering the shocks and struts are in good shape. If they are bad your ride will suffer no matter what springs you use.

If you want linear rate springs there is a solution. Check out Ground Control. They make a weight jack spring pertch system that works very well with linear rate springs. The spring fits between the 'pertches' and you can compress and decompress the spring by adjusting the pertch. You buy whatever linear spring rate you want, then use the weight jack system to specify the ride height. You can also adjust the height (aka adjust the geometry) whenever you want after they have been installed. This gives you alot more choices than the Eibach progressive spring route. You can specify height as well as spring rate (unfortunately, one you install a certain spring rate you cant adjust that withoiut putting a different spring in there). Combine this with a set of adjustable shocks/struts and now you have the hardware to tune your setup for whatever type of ride you want. Probably the closest you'll get to coilovers without actual coilovers. This is basically the route I'm going with my track car. Be aware that when you lower the car, you change the geometry. Because the weight jack system gives you HUGE adjustability, you really need to keep this in mind. Dropping the car 1" wont make a noticable difference in handling charasteristics during spirited street driving. Dropping a car 2-3" probably will. If you want the 2-3" drop anyway (like me hehe), there are things you can do to correct the geometry, namely being adjustable tie rod sleeves (Baer bumpsteer kit), and LCA relocation brackets. Revlimit has the weight jack system and he has had some really good results. Definately quality stuff.

My roadracing track car spring setup will include these parts:
Ground Control front and rear weld in Weight Jack kit
4 sets of front 5.5" Nascar springs 600 700 800 900 in lb
3 sets of 2.5" rear springs ..150 200 250 in lb
Geared for the best handling, not the best comfort ...

This will be the first time I have the hardware to really experiemnt on the track, so I went with multiple spring rates (found a package deal). I'll be learning alot about how the different spring rates really affect the handling characteristics.

For my street car I plan to use this spring setup:
Ground Control front and rear non-weld in Weight Jack kit
Eibach Sportline Progressive rate springs
Geared toward the best comfort and alright handling ...

Should be good for street use.

 

You've been given so bad info- please let me explain and correct.

1st off- ride height of shocks has nothing to do with their dampening force- as long as they are not grounding out in compression or rebound strokes then there travel height does not matter.

2) weight jackers will not allow you to stiffen and soften one set of springs- again -there is no spring rate adjustment with weight jackers.

The intended use of weight jackers is for circle track purposes only- what they allow you to adjust is the amount of chassis weight that will set on both the "left front and right rear" and "right front and left rear" tires. Weight is usually lightened off of the right front and left rears so the car chassis will rock back and forth more on the other two wheels (example of like 52% on LF & RR, and 48%car weight on RF & LR) making the car looser- and vice a versa.

Now when a car is setup like this, it is intended for turning in one direction well and one direction only ( Thus circle track). The more weight jacked onto the LF & RR by turning the front left weight jacker up causes the RF and LR to in accuallity come off the ground more than the LF & RR. When you transfer weight from braking and entering into a left hand corner, the chassis attitude will shift onto the fronts- causing even pressure on the fronts but lifting pressure more off of the LR than the RR, because of use of weight jackers, causing the rear of the car to have less grip than the front entering the corner ( Loose). as you motor through the corner and come back harder on the throttle, the chassis weight will then re-shift mainly to the rears and allow the car to push out of the corner (understeer)

If a car is too losse going in and pushing too hard coming out- then you reduce this setting. Its just one more very technical element to setting a chassis.

Now with that said- will allow you however to put in a set of front springs that are stiffer than the first set and the suspension will set higher because it won't compress as much- you than instead of cutting the springs, can just turn down the weight jackers evenly on both fronts to set the ride height back to were it was with the fisrt set of softer springs NOTE: custom springs will have to be cut and sized even for use with a weight jackers system.

If you want to use this setup to at will raise and lower your front ride height- don't think any futher- you will have to re-align your car everytime you change your ride height more than about a 1/2" or you will have improper tire wear.

Any other question or further clarification needed just ask and I'll try to explain in more depth. Sorry about the novel but this can get pretty complex. This same adjustments can be made with the use of adjustable compression and rebound shock to also help correct oversteer and understeer problems.

By the way Crazy Hawaiian- I'm AFGT in case you didn't know. Ithink you know correctly on the spring rate part but I was just clarifing because you kind of contradicted your post in saying weight jackers will compress and decompress springs but then said in quote that you can't change spring rates I added that part of your quote for your benefit- that is correct.

 

Thanks for the great explination, I didnt know that was the original intention of the weight jack setup. The track I race on has left and right turns so all my stuff will be set evenly. I still have alot to learn about the actual tuning of the suspension and how it affects the handling. But I dont think I have any bad info in this post, maybe a misunderstanding? As far as the shocks, you are right, them being compressed by the lowered ride height wont be a big concern unless they are being compressed to the point of grounding out. But thats why I brought it up, the weight jack system will allow you to lower the ride height so much (3.5" down) it really can compress the rear shocks enough to affect how they ride (we're talking comfort here). I wanted to make sure whoever installs this and expects to slam the car knew this. It depends on how its set up. And yes I have experienced it, I'm not just making this up. Revlimits car handles great, but it will hurt your back. Also, I never said the weight jack system will allow you to change the spring rates, I said having a weight jack system and a bunch of springs with different spring rates gives you the ability to adjust ride height (via spring pertch) and spring rates (via swapping springs). But thank you for explaining this for us. Its good we have a bunch of people here to add input and cross check eachother. I am also aware of the alignment issue. I dont plan to be changing the ride height very often, but it is a usefull adjustment. For instance, if I need to use the car to drive to the store and it wont get in the driveway there or clear the speedbumps. Adjust ride height up, goto the store, come back and drop it down. Or I need to raise it to fit it on the trialer so I can drive it to the tracks, raise it up, drive it up on the trailer, tow it to tracks, drive it down, lower it back down. Very usefull ... but like you said not good to drive with the alignment off because it will cause uneven tire wear.

 

Oh hey wasap AFGT!! Didnt know it was you. Can you recommend someplace I can read on how tuning the setup will affect how it handles? Or can you spare the time to give me a quick lesson? Like adjusting this, this way, will give you more oversteer/understeer or stuff like that? Its rare I get to speak with people who know about suspension tuning. I try to learn everything I can. Revlimit asked about it earlier but I guess there's only a few of us here who are really into it. I'm more theory than actual output, so I'm trying to catch up on the actual output part. Thanks!

 

CH, you really need scales under each wheel to effectively set the weight jacker equally. Then while racing with pit stop time of the essence, the weight jackers allow for quick small changes in handling in limited time frames. It would take too long of course to change swaybars, springs or shocks in a pit stop so this was developed.

You have good points on the benefit of weight jackers for your use with different spring rates and wanting to maintain ride height ( also the getting into a trailer idea is great!).

Here's a great link to Bilsteins shock compression-rebound adjustments for chassis tuning that you should bookmark, study, and always have resource to. Click on the link and page down to the bottom where it talks about tuning your chassis. http://www.bilstein.com/motorsports/oval.html

It shows circle track info but you get the basic ideas of what the settings will do entering and exiting. Roadrace settings should mostly be equal left side of the car to right side of the car- front to rear can and will vary.

I have owned a great book since I was a little snot that is titled "How To Make You Car Handle" by Fred Puhn. This book alone will intrege you for years- it is what enticed me into suspensions at an early age- I am all self taught and owe alot to this book for basic understandings of such things like unsprung weight and roll axis. I have recently in the past few years finally perfected my welding skills enough to design and fab my own suspension geometry when needed. Its all about mathamatics and force.

Dean

 

Thats really cool!! I'm gonna go find that book!!! Thanks!!

 

Man this is a lot of info. Good reads
The whole thing about the struts grounding out was my whole reason for questioning those fabricated brackets back when that topic was hot stuff.
All of this suspension stuff is talked about in my dynamics class between my fellow Formula SAE team members. I'll leave that stuff up to them since they seem to have a good handle on what's going on. All I know is in a good handling car you want predictable feedback before your limits (not as stiff as possible) and you want around 50/50 weight depending on the drivewheels. Also that lowering the CG is one of the biggest improvements you can do to a car's handling. Other than that I'll just knod my head and say sure, that sounds good....I'll be over at the dyno making more hp, you guys make sure the car can handle it .
I'm going to see if we've got that book on suspension, sounds like good stuff.
Does anybody have pictures of weight jacks in an f-body?