SOCOMech

I've been doing as much research as I can but can't seem to get this conclusion......Is there a lowering spring for the Boss that you don't have to replace other parts with? I like the sound of the FRPP "P" springs but some have said you need to get an adjustable panhard bar and LCA relocation brackets. As for wheels, I've narrowed down my choices but would like to just get new wheels and run the stock tires for now.....Can you get away with running the stock 255 tire on a 9.5 rim? I'm not fond of the "not wide enough" look you can get when the rim sticks out further than the sidewall of the tire, but most of the aftermarket wheels are only coming in 9.5 it seems. Also, is there much of a change if running 275's all around like some are doing? Thanks for any help!

boss man

I have aske the same question many times and got many different answers. I then reached out to Gary (cloud9) after he did his suspension.
His answer to installing the springs help me to pull the trigger on Ford Racing P springs, panhard bar, relo brackets, rear LCA and jounce bumpers. I will be placing an order later this week.

Let me share Gary's response with you and hopefully it will help you as much as it did me.




I like the forums for what I can learn and am certainly happy to share my experience.

The stock dampers will work just fine with the M-5300-P springs. The dampers I went with just give a wider range of adjustment. The adjustable panhard bar has two jam nuts on either side of a centering nut. You loosen the jam nuts and rotate the centering nut untily our axle is centered under the car. Some people use a plumb bob at the outside of the wheel well to measure the distance to the tire, but you can also just eyeball it. If you look now, you'll see your axle is probably shifted slightly to the driver side. When you lower it another inch with those springs, that shift will be exaggerated because the panhard bar attaches to the frame on the pass side and the axle on the driver side so simple geometry makes it push left

The lower control arm relocation brackets aren't very expensive and I would recommend getting those even if you're not replacing the factory control arms. When you lower the car you need to relevel the control arm angle for best results. They will help your car hard launch and maintain the best traction under heavy acceleration if you correct the angle. If you do order them, install the control arms in the upper of the two holes.

If you decide to upgrade your control arms at some point, the benefit will be the elimination of wheel hop and better traction under hard acceleration. The main reasons we get wheel hop from the factory control arms are the rubber bushings. They deflect under heavy load. The reason the factory installs them is to minimize NVH so it becomes a tradeoff between noise and performance. The control arms are something you can certainly add later.

Good luck!

Gary

JeffL

so with P springs the front will not be any lower? the measurements are based off a GT the Boss is 1" lower than a GT in the front right?

I want to do K springs. with as little else as possible. panhard bar? I've seen the questions come up before and have read some other threads probably just going to have to do it and see what happens.

5 DOT 0

Yep Gary and I are on the same page but I'm not going as far as he's gone. You can read about what I just ordered at the link below.

You can run the stock size front tire on a 9.5" wheel. Going square requires a change in the sway bars and I wouldn't recommend that for the street but if you're going to track your car it's an option.

You need a panhard bar to square up the rear suspension and will definately be needed with the K springs.

http://bossmustangsonline.com/boss-3...sion-upgrades/

5 DOT 0

The P springs will lower the front of the Boss about a half inch.

JeffL

I'm so lost with Ford Racing measurments. So the Boss is only 1/2 inch lower in the front than a GT from the factory? I might just go with Ps then.

5 DOT 0

If I recall correctly the Boss is 14mm lower in front and 1 mm lower in the rear compared to a GT.

tj@steeda

Steeda has a great set of Boss Springs that I would like to provide for you, take a look and let me know if this is something you are looking for. These springs will lower the front of the Boss by .2 inches and the rear by .7 inches.

http://www.steeda.com/store/boss-per...g-springs.html

Best Regards,

TJ

fking1

Check out Eibach Sportlines.
Fit 12 & 13 Boss and lower front 1.0 & rear 1.8.
$359 on their web-site.
I am considering these.
I had Steedas on my 04 Cobra and they did not lower the car as Steeda claimed & ended up cutting a coil off.

cloud9

If you want to do the K springs, you're not going to be able to do "as little else as possible" They drop the car 1.5" all around. You'd absolutely need an adj panhard bar and LCA relo brackets. You'd also really throw off your front end geometry and need a bumpsteer kit and different ball joints to reset your roll center.

If you want to do the least possible and are more interested in the look, get the Boss specific springs from Steeda or the ones coming out shortly from FRPP. With those springs you may not need the LCA relo brackets especially if for street use, but may still want (not need) the adj panhard bar.

If you're more interested in track performance but want to make minimal changes while still lowering the car 1/2" in front and 1" in the rear, go with the P springs (heavier spring rate) as others have articulated above.

The "P" springs lower a GT 1" all around. The Boss comes from the factory 11mm (~1/2") lower in the front and 1mm lower in the rear than a GT.

fuhrius

Gary, would you have considered going with the k springs if the bump steer / ball joint kits were available? or is that drop simply too low?

cloud9

I did consider them and still will pending release of the new front LCAs with bumpsteer/ball joint kits coming from FRPP. That's why I held off on the front LCA bushings for now as well. When those come out I will reevaluate the K springs at the same time. Ultimately the K springs will degrade the streetability both from a ride and clearance perspective, especially for those with LS or WC front splitters. That becomes the tradeoff. For now I'm very happy with the setup I've got and the streetability is still excellent. From what I'm told the performance of the K springs isn't significantly better other than lowering the car further.

JeffL

Thank you!!

I'm really just in this for looks. Will have to re-eval what I'm going to buy.

JPC

I have installed the Eibach pro kit springs on my 2012 Boss and it has lower the rear end.
I researching now if I should install relocation brackets for the rear
I read that the LCA should be level to the ground for best handling, true?
below is a picture of my LCA which are NOT level to ground.
....and I do open track the Boss :-)

thoughts?

5 DOT 0

The relocation brackets are recommended by Ford Racing when lowering your car to maintain the correct geometry. See the link in post 4 of this thread.