Spring/strut combo

[jake_zx2]

Hey everyone, I am planning on upgrading to eiback sportline lowering srings sometime soon, and I was just wondering if anyone has any experience on the best strut to run with these. I'm trying not to go through struts every 10k miles, so I want something that will perform well and also last long (adjustability would be nice, but isn't a must). I was looking at either the ford racing shock/strut kit or simply koni yellows. Any preference between the 2? Any better options out there?

 

[jake_zx2]

Oh, forgot to add, I plan on road racing, not drag. And I also plan to get lca, uca, sway bar, and panhard bar to complement suspension

 

[MechE]

I have no experience with these springs but my research on this forum has steered me away from them. As far as I can tell eibach makes a good product but these springs don't have the rate to keep our cars off the bumpstops for how far they lower the car.

 

[jake_zx2]

Oh really? their spring rate is pretty close to the eibach pro's, so I didn't think it would be that bad, especially with stiffer damping... that's a shame if its true though, I really like the ride height with the sportlines

 

[MechE]

Oh really? their spring rate is pretty close to the eibach pro's, so I didn't think it would be that bad, especially with stiffer damping... that's a shame if its true though, I really like the ride height with the sportlines

Well, if they are only as stiff as the pro's then that is a problem. If you are lowering the car more, you would need to address the reduced compression travel, and the increased roll. One way would be to increase spring rate.

Also, what is your application? Is this mostly a track car?

 

[nbk13nw]

My first set were the Sport lines and Ford Racing struts. The stance was awesome but the ride was awful. This was on a 2005 GT.

Sent from my SM-G925V using Tapatalk

 

[jake_zx2]

mainly daily driver, but I live about an hour fron nurburgring, so its occasionally a track car. don't mind a rough ride, my old daily was on coilovers and that ride was terrible, but I can deal with it.
according to american muscle, spring rates are as follows:
Eibach pro kit-Front: 171-228 lb/in. lowers-1.3"
Rear: 180 lb/in. lowers1.4"
Eibach sportlines- Front: 126-274 lb/in. lowers-1.6"
Rear: 86-240 lb/in. lowers-2.0"

 

[jake_zx2]

I'm also leaning more toward the koni yellows, mainly due to the adjustability and price of a sale I found. would anyone advise against this?

 

[Norm Peterson]

You don't need to be lowered at all to pull over 1g at a track day session once the tires have fully warmed up. I've got datalogs showing 1.3+, which would still be 1.2+ even if that part of the datalogging is inertial and assumes that the car does not roll at all. MPSS tires on pretty wide wheels.

There are people on this site who don't care for the Koni yellows for various reasons. But for a dual-duty street/occasional track day car the only reason that really matters is that the yellows don't seem to tolerate very much lowering.

A better spring choice might be BMR's GT500 handling springs (claiming 260 lb/in front, 220 lb/in rear), which drop the front about half an inch. You might end up having to still do something about the rear ride height (it wants to drop about an inch) so it doesn't look like a 'taildragger' Ford/Mercury sedan cruiser from the 1950's. I can tell you that yellows are enough shock and strut to control these springs, and that you might also end up wanting a little more rear sta-bar stiffness to bring the handling balance back to where it is now as well.

Gratuitous picture, about 1/2" suspension lowering with 1/2" lower #BecauseShorterThanOEStreetTires. The even shorter track tires drop it about another quarter inch.

Norm

 

[jake_zx2]

thanks for the input norm!
I know the car already handles pretty well, my issue is the body roll. I really cant get adjusted to taking a hard turn and having that much movement in the suspension (especially my other car had 8k coilovers and weighed over 1000 lbs less than the mustang).
I also like the look of the 2" drop and the "leveled out" that the sportlines provide... I'm not a huge fan of the rake.
as for the koni's, good to know that they don't handle lowering too well, thats my absolute biggest concern with any strut. Do you think ford racing struts would hold up better? and is the $250 price difference between the dynamic and adjustable shocks?

 

[Norm Peterson]

I have no real basis for opinion concerning the FRPP shocks/struts, as I never considered them.

I don't particularly notice the roll I've been getting (about 2.5°/g suspension, around 3.1°/g suspension + tires), so I don't know what to tell you there, either.

The rake is where it ended up with a more or less consistent and very small amount of lowering to suit reasons other than appearance, "stance", or whatever other subjective. If the car works well enough looking like that, then it'll be exactly right for me. Form following function because I just can't bring myself to work it the other way around, no matter how "popular" a particular appearance preference might be

Norm

 

[jake_zx2]

I agree that function always comes before form, but a good compromise is never such a bad thing. working "well enough" souldnt have to exist if its all about function over form.
The sportlines actually have a higher spring rate, as BMR claims on their website that they are 165lb/in front and 160lb/in rear. and since they arent as low, it will have a higher center of gravity and cause more roll than the sportlines would have.
Like I said, I'm really sensitive to the feeling of roll, because my other car didnt have any, and I autocrossed it for over 2 years. I got too used to that. I would put the mustang on coilers, but that would completely kill the ride quality. I know it's not great with the sportlines, but I imagine it's managable

 

[Boaisy]

Vorshlag sells a kit with their camber plates, Bilsteins, and Eibach or FRPP springs. I had the Eibach Pro springs on mine, and it was just fine. Didn't feel the need to lower it to the Sportline level. The Bilstein housing is shortened to accommodate the lowered ride height, and it is a monotube shock/strut vs. the twin tubes of the Koni's.

http://s197forum.com/forum/showpost.php?p=2325944&postcount=9

http://www.vorshlag.com/product_info.php?cPath=141_142_179&products_id=559

 

[jake_zx2]

that looks pretty good, but holy crap is that expensive! at that price, would you really choose them over eibach pro-street coilers? you could get the coilovers and the cc plates for a little less and still have money for lca's or a panhard bar

 

[jake_zx2]

p.s. the beatiful sounds of that coyote makes me hate my life lol

 

[Boaisy]

If you are going coilovers, expect to spend about $3k+ for a coil over kit that is even worth buying. Even then, with these cars, most people are using spring rates higher than what Eibach offers with the high end coil over kits.

 

[Norm Peterson]

I agree that function always comes before form, but a good compromise is never such a bad thing. working "well enough" souldnt have to exist if its all about function over form.

Compromise is understood. And the compromises between suitability for the street and capability on the track - given that whatever amount of talent I have as a driver is undoubtedly the limit for the latter - all stand ahead of compromises to suit any subjective considerations of appearance.

Frankly, I don't care for lowering to the extent where the wheels are obviously un-centered in their openings even if they aren't tucked up behind the sheet metal. To me, too little of a gap at the top makes the car look like it's been overloaded and suggests that it shouldn't ever be driven very hard. At ~1/2" down from stock my '08 is getting about as close to that as I care for it to be, so it could be that everything just happened to fall into place at the same place this time. No way would I ever drop it another half inch just because most other people looking at my car might like that look better instead.


Norm