Lowering the rear end on a stock height 2010 SVT none PP

Sorry MHUNSER....that drop is too much.

I decided to measure everything before I took out my existing stock springs.
I put as much back on my car as I could, added measured weights for the missing exhaust / seats. Waited a day for car to resettle - took multiple measurements to be sure.
My 2010 is sitting lower than from the factory - no suspension mods & stock tire sizes. Probably springs sagging over 11 years ???
Fender lip heights (difference of 3/4" higher in rear) front 28 9/16 rear 29 5/16
I read 2010 stock was 30.5 rear fender height - I'm down 1 3/16" already - not expected
Tire to lip clearance (Difference of 7/8" more rear space} front 2 1/16 rear 2 15/16
Why wasn't it exactly the same 3/4"?? Tire size! - front is taller so that explains some of the rear spacing increase from 3/4" value to 7/8".
GT500 stripe height - top of stripe behind front wheel and in front of rear wheel
front 16 15/16 rear 18 15/16 (Difference of 2" exactly as it sits)
So without touching the front I can't really go down more than 3/4" without losing the rake appearance from the stripes. At 3/4 front and back fender lip heights would be the same. This is not what I expected. I need to rethink my options now.
Measuring pinion angle now -- currently my stock control arms have a slight pitch upward from the body to the axle (read that's not good either) - measuring angle of that too.

The proper way to measure ride height is from the center of the rim to the fender lip. This removes tire pressure, ground variations, and any other possible factors. Roll car back and forth before measuring to get the most accurate measurement. I don't have a current good pic with my coilovers. I still have a slight rake, but I measured all the way around to verify an accurate set up. I included a pic for reference of the Vogtland springs, shorter spring with higher spring rate than factory. Slight pitch on LCAs should be ok if you are using the car as a daily driver, but UCA or LCA relocation brackets are needed to correct this. Tire to lip spacing will be different front to back if both fenders are the same height due to various factors. Tire size, suspension, spring rate, and the way the car is built. I have changed mine mine several times to get the right setup for road courses while being somewhat friendly on the road. Currently, all I need to do is tighten my shocks when I go to the track. Hopefully some of this helps. Good Luck!

Thanks.... I really thought I had much more rear rake to play with than my car actually has (like another 1 1/2 inches). I can't really lower in the front - live in upstate NY and the local roads are very bad and there are many abrupt inclines everywhere. I had the splitter bottom scrape many times and fortunately it is flexible enough to rebound with no visible damage from the front view. Lowering my front any would probably cause front end damage.

On the fence with any spring changes now but I'm ordering new shocks to replace the back stockers. Looked at Strange but there are complaints about popping noises at slower speeds so I think Viking Warrior double or triple adjustables...hopefully the only set I will probably ever buy for it.

P.S. Your front splitter looks way too low for where I live!

Actually dropping the rear will raise the spitter because the car is pivoting on the front axle. However, it will be minimal. It just won't get worse.

Catmonkey said:

Actually dropping the rear will raise the spitter because the car is pivoting on the front axle. However, it will be minimal. It just won't get worse.

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Yeh, I thought about that but it would only raise it a fraction of an inch when I did the math. My splitter's very front bottom is currently at 7.1 inches

Here's my next problem....

My measured pinion angle is +.2 NOT good and I measured it using two different methods and tools.

My balancer is sloping downward towards the rear at a negative 1.8 degrees
My pinion is sloping upward towards the front of the car at a positive 2.0 degrees
-1.8 + 2.0 = .2 degrees positive pinion angle

My one piece driveshaft is sloping downward at a negative 3.8 degrees which is good but doesn't really matter.

So how did my pinion angle get so far off on a stock rear-end - replaced pinion bearing in car but never removed anything that would have caused an angle change of that kind of magnitude.

Even worse is this....I think the rear of the car is sitting 1 3/16" lower than it was when new. (Don't now about the front height drop.)
In my mind I think that should have made the pinion angle point down even lower to the ground which should have made my pinion angle go more negative. Instead it is positive and nowhere near the -2 it should be at.

Baffled at this...looked over LCAs, panhard bar and UCA mount and bushings and they look fine and centered. No visible reason for the issue.

I don't think relocation brackets will fix this and don't want noisy adjustable LCAs - only option I think is an adjustable UCA along with the NVH it will create.

Use this formula: (-1.8) MINUS (+2.0) = -3.8*

Read post #11 in this thread: https://www.svtperformance.com/thre...-14-driveshaft-upgrade.1182450/#post-16350318

You are not that far out. Car should be on a level surface with front and rear suspension loaded for accurate measurements. A one piece drive shaft is less forgiving than the stock two piece design in terms of pinion angle. If too far off, a one piece driveshaft will hum like off-road tires.

Thanks, but I don't think I explained it very well so let me try again....

If I put a protractor on the balancer it reads -1.8
If I slide that same protractor as it sits all the way to the pinion hub shaft and take a reading off of it in the exact same manner it reads -2.0

My two shafts are almost exactly in the same vertical plane already at resting height and weighted down a little.

MY pinion angle calc is
-1.8 - (-2) = +0.2
As it sits right now when under acceleration my rear end will rotate clockwise at least 2 degrees so it would make my current pinion measurement reading go to -4
so at full acceleration I am at -1.8 - (-4) = +2.2 (or even possibly higher) and not the (0) that I should be getting.

I think right now my pinion measurement should be about level which would give me a reading of around 0.0 instead of the current -2.0 value that I have. This is assuming my rear end pinion angle will only change about 2 degrees under hard acceleration.

Not to scale, but try thinking about it like this:

Eibach coil overs have been on my car since Shelby installed them in late 2008/09. Yes they cost more, but there is no "trying to figure out ride heights, spring rates etc." Eibach specs them differently depending upon application/year, Mustang GT, GT500 and I believe also breaks their springs down to Coupe and Convert., or at least they did a few years ago for the S197. It is nice to be able to change to wider tires, narrower tires, taller, shorter and adj. the suspension as needed. The Eibach gives a firm confident ride, not harsh, not bouncy, just a nice tight performance car feel without sacrificing the ride. <<<That is my personal experience......



R

My experience with coil-over shocks out back were short lived. The S197 chassis does not lend itself well to that application. Not only do they limit wide wheel and tire choices, the shock bracket on the rear end was never intended to support the weight of the vehicle, much less lateral loads. The wheel adjusters discussed here do the same thing and smooth body shocks are available in a lot of different configurations to fill damping needs.

Catmonkey said:

My experience with coil-over shocks out back were short lived. The S197 chassis does not lend itself well to that application. Not only do they limit wide wheel and tire choices, the shock bracket on the rear end was never intended to support the weight of the vehicle, much less lateral loads. The wheel adjusters discussed here do the same thing and smooth body shocks are available in a lot of different configurations to fill damping needs.

Click to expand...

^^^^I agree with that!! I would never have gotten 325/30's on the rear of my car with true coil over rear shocks.......They do limit the area in the rear inner fender well, plus like you said, the oem "shock pocket" in the body/inner well, where the upper portion of the shock attaches was never designed by Ford to "also" be loaded with the weight of the car.........but the coil over shocks look cool......

For ease of coil over adjustment, Strange Engineering offers (or offered)......I believe they are called torsion bearings?.....they can be installed between the adjustment plates below the coil over spring and make turning the adjusters much easier since the collar is turning on needle bearings instead of flat surfaces. I came across those bearings a few years ago and bought two correctly sized sets, one for the Eibach Pro Street-S coil overs that are on my car, and one set for a spare Pro Street-S set that I have. The only problem is, it requires complete disassembly to install those bearing plates, so those really need to be installed before the strut/shock is assembled.

R