SR-71

I've searched the forums, but haven't found the answer to my question.

I need to restore (and hopefully improve) my suspension. There's nothing "wrong" with the present WS6 suspension, except the original bushings are worn out.

Plans include Polygraphite bushings all around, upgrades on the trailing arms and panhard bar, frame stiffeners, Bilstein shocks/struts.

The only question is the springs. My question is a little different than what most guys ask.

Lowering the car is not an issue. I can take it or leave it. It's got the "4X4 stance," but that's only wheel opening spacing. I have trouble getting my low-profile floor jack under the car now. I have to take the lifting pad off to get it under the car's front crossmember. My drive-on ramps barely fit under the bumpers. I already have to go through street dips at an angle, and be careful not to bang the front air dam in parking spaces. Lowering the car will just make all of this worse. It may appear to have a tall stance, but it has only 5 inches of ground clearance under there as it is! But I can live with lowering the car an inch or so.

I know Eibachs will not hurt the handling. In fact, they may improve it a little. But the WS6 certainly has no handling issues. So I'm not concerned about the handling.

Finally, the question--
Has anyone put Eibach Pro-Kit springs on their WS6? If so, how did it affect the car's ride? Softer? Firmer? About the same?

I consider the present ride to be a bit harsh. Again, it's OK. I can live with it. But I wouldn't mind softening up the highway ride a bit.

Eibach won't say one way or the other. All I get from their tech guys is their marketing response about what will fit and it will lower the car. I already know that! But they will not give me a single word about ride quality compared to the stock WS6 springs. I find that funny/strange/sad.

Anyway, any feedback on your actual seat-of-the-pants experience with the ride quality of Pro-Kit vs. stock WS6 would be greatly appreciated. I'm not interested in comparisons with the SportLines. I already know about those-- too low, too harsh for what I want.

Please, no comparisons to non-WS6 Firebirds or to Camaros of any variety. They're not the same under there. WS6's only.

BMmonteSS

From what I've seen, Eibach just makes a spring that maintains the factory spring rate but lowers the car 1.5" or what ever it is they advertise. The problem with this is that with the car lowered you have less suspension travel to soak up bumps. What you end up with is a car that bounces off the the bump stops all the time. Most people don't relize this and just think it's their "mad tyte yo!" springs making their car "handle" better. If I were you I would get a new set of moog springs and trim them to get the ride height you want. By trimming the springs you are going to increase the spring rate a bit which should help keep the car off the bump stops. This works well for mild height changes, if your looking for a big drop (2" plus) then you need to go to a stiffer spring.

This may sound crazy, but a car with really stiff spring and shocks will feel better to the posterior than a car with soft springs and shocks that hits the bump stops all the time.

matt_p

Trimming the spring increases the spring rate? It does quite the opposite.

V8Rumble

iTrader: (2)

Given what you've said below...

I'd almost wonder if it doesn't already have lowering springs... I have a regular (non-low-profile) jack, & I don't have to deal w/ that...

Also, given how useless Eibach's tech line seems to be, I'm rather strongly dis-inclined to buy anything from them now...

As far as the harsh ride, well, I'm thinking that it might be worthwhile to get opinions on different tires, so that when the time comes that you need them, you can get a set that provides a reasonable compromise between performance & ride quality.

Wish I had a good answer for your specific questions, but hopefully this is worthwhile as "food for thought"...

BMmonteSS

Matt, you need to do a little research. A spring is nothing more than a big long strait bar that has been wound into a coil. If you make that bar shorter it will be harder to bend it.

Guest

Sounds like the same garbage they've been spewing for 15 years... no, we arent going to tell you what our springs are but you should buy them! If you search this board you'll find some spring rates for both the stock springs and Eibachs 2 offerings.

The rears are progressive (fronts may be too but I dont feel like digging out my box) so it may ride a little better but thats hard to say. IMO the shocks have much more to do with the ride than the springs. I never had any problems with constantly hitting the bump stops so I'd say if you arent running the car hard all the time you wont have a problem. After running both though, I prefer the WS6 springs with a little cut off. Ride isnt bad and the car is much more pretictable.

matt_p

I always thought it as the other way around. Cutting the springs means less material in the springs, thus less material to resist the weight of the car

Sonix

iTrader: (1)

I remember seeing a WS6 sticker in the center console of my car- but I wouldn't get too excited about it, it's just a sticker. With that in mind, my car is suitable to compare to yours, so I shall chime in

I used moog 5664 front springs (the stiffest factory springs you can find), and moog cc635's in the rear. I really like the ride, yes, it's kind of harsh, but not unbearable. Nothing to rattle teeth out, just quick rebound after bumps, etc. Really hugs the road. People always say it feels like a race car.

I like moog because it's a factory replacement part, easy to find, and cheap. Aftermarket stuff like eibach will be much more $$, and virtually the same (specs wise). You just get stickers with it.

I'm also using KYB stuff all around, along with poly everywhere, and stock boxed LCA's, and panhard.


Now my question to you SR-71 - you're running a 400SBC, with 416 heads, and a compxe256. How do you like that combo? I figured those heads and cam would be too small for a 400? What RPM does it pull to?
2nd, how did you seal the air cleaner to the power bulge? I read your description, and sounds like how i'm going to do mine, do you have a picture perhaps?

rhomanski

To answer your question I have a gta with ws6 and i put the eibachs on it as well as bigger bars and hotchkiss lca's and it drives excellant.The ride is a bit stiffer in my opinion but well worth it for the better handling.

Guest

I suggest you look into what gives a spring its properties. It will make it stiffer if you cut coils off.

matt_p

I'll just take your guys' word for it.

It'll be good to know when it comes time to put the IROC springs in my garage in my Z28 and the rear is too high.

SR-71

Nope. Cutting coils makes the spring stiffer. Multiple articles in CarCraft, HotRod, etc., back this up and explain it. As BMmonteeSS said, a spring is just a coiled rod. Shorten a rod, and it takes more force to bend it. It's not "stiffer," really. It's a matter of physics.
----------
I liked all the feedback from everybody, but this is exactly the answer I was looking for.

I already like the ride as is, and I think the other stuff I'm doing will give me the handling I want. So I'll stick with the stock springs and get rid of the OEM replacement shocks and struts in favour of some "real" units.

SR-71

First, so far I love the combo. But there's more coming.

The 416 heads are "adequate" for the build. That means, yes, they really are too small. But they flow better than any original 400 heads did, and their small chambers gave me the compression I wanted inside my present budget. Porting and polishing added 46% to the flow (I had them flow-tested before and after.) But the flow is still only about 110% of what the engine could want, so the flow is barely there. They are 180 cc ports, so the throttle response and torque are great. With the pistons that are in it, I was able to make 9.3:1 compresseion with 0.051" head gaskets. The present build should be making over 400 ft-lbs from off-idle to 4000 rpm, and that's how it feels.

I want to put on a set of aftermarket heads, though, with modern chambers and better flow. Should add 100 ft-lbs across the whole range. When the budget allows, I'll decide which ones, but I'll still keep the port volume at no more than 200 cc's.

The XE256 cam was recommended to me by a CompCams tech, after I told him the car, weight, gearing, other parts in the build, etc., along with what I wanted. What I told him was that I wanted "raw street torque, pump gas, and a 5300 rpm red line." (I'm not sure if the bottom end is built for revs higher than 5500.) So that's exactly what I got. This cam is perfect for that. With 9.3:1 static compression, the dynamic compression comes in at 8.2:1, which is right on for iron wedge heads and 91 octane.

The cam will let me go to a newer iron head with the same compression, or as high as 10:1 with aluminum, and still run pump gas.

For the air cleaner, I cut the snorkel off of the stock air cleaner, and sealed the hole. Then I got an OEM replacement K&N filter. According to K&N's own calculator, that's not big enough for the air this engine wants, so I put on an XStream lid. The lid is a bit smaller than the filter, so I cut a 1/8" groove in the filter's top seal for the lid's edge to seat into. Seals perfectly. All the air cleaner assembly needs is one of those funnel things to replace the stock spacer, like Turbo City or Holley sells.

The story on the hood:
When I first bought the car (for my daughter's first car), I didn't realize it was a Formula 'til we got it home. The original RPO sticker was long gone. Previous cheapskate owner had hit something in front, hard enough to damage the hood and fenders, so it had cheap, light, aftermarket standard hood and fenders when I got it. The 16" factory wheels and tires and the "Performance Suspension" dash plate were a clue. The drive home from the budget lot was the second clue. A thorough under-car inspection confirmed it. After months of salvage scouring, I found a pair of original fenders and a damaged bulge hood, with induction hardware and insert missing. I found the insert from an online salvage. Since I was planning to run the bulge wide open at all times, that was all I wanted.

I cut a piece of sheet metal to fit the underside of the bulge, extending over the air cleaner, and sealed it all to the underside of the hood. I cut an opening 1 inch smaller diameter than the original air cleaner, and put a foam ring around the top edge of the air cleaner to seal against the metal. Then I put in a new "standard hood" liner with a hole cut to fit outside the foam seal. So the underside of the bulge is all hand-fabricated, and covered with a hood liner so it looks "almost" stock. With the hood open, it looks very much like a late 60's cowl induction Chevelle setup. Shine a light down the bulge from the outside, and you can see the K&N parts. Last bit to go in is a screen of some kind over the bulge opening to keep leaves and such out. I'm looking for some small-pattern honeycomb screen material, if I can find it. I'll do that when I re-do the paint this spring.

SR-71

.

Steve89GTA

My 89 GTA had the original WS6 springs. I know you think they are pretty tight but the Eibachs will be just a small tad harsher over bumps BUP, the car will handle much, much better around turns.

They were a great investment!