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P springs installed

Mad Hatter

Gotta go Faster
Santiago, Chile
I just got the car back from the shop. P springs are in with the FRPP bump stops, the ride was much better then I expected, maybe I am wrong, but even with 275/35-19 tires up front the ride felt smoother/less harsh then the Boss springs. Looking at the data posted on the forum... see below... you would expect the ride to be harsher then stock, at least up front .... Have not tracked the car yet though.

Since the fronts are 204 lbs./in vs the Boss at 148 lbs./in and the rears P's are 165 lbs./in vs the Bosses 185 lbs./in

Does this mean I should feel more balanced with my square setup? Maybe run with front and rear shocks on 5..?

It took my a while to find this post, so I will put it out their again, handy to have

Mustang GT (2011+) Stock: Ft 122 lbs./in Rr 154 lbs./in * Source, Maximum Motorsports
Brembo Stock: Ft 131 lbs. /in. Rr 167 lbs./in
Boss Stock: Ft 148 lbs./in. Rr 185 lbs./in
Boss LS Stock: Ft 137 lbs./in. Rr 191 lbs./in
Eibach Pro-Kit: Ft 159 lbs./in Rr 193 lbs./in * Source, Maximum Motorsports
FRPP K Springs: Ft. 188 lbs./in Rr 221 lbs./in *Vorshlag Tested
FRPP P Springs: Ft. 204 lbs./in Rr. 165 lbs./in *Vorshlag Tested
Steeda Competition: Ft 225 lbs./in. Rr 185 lbs./in
Steeda Sports: Ft 200 lbs./in. Rr 175 lbs./in
Steeda Boss Springs: Ft 225 lbs./in. Rr 195 lbs./in
Steeda Ultra-lite: Ft. 195 lbs./in. Rr. 175 lbs./in
Eibach Pro street Coilover: FT. 225 lbs./in Rr. 90-200 lbs./in * Eibach Spec sheet
Eibach Pro R1: Ft 225 lbs./in Rr 250lbs./in * Eibach Spec sheet
H&R RSS Clubsport: Ft 630 lbs./in Rr 515 lbs./in * H&R Spec sheet
302S: Ft 600lbs./in Rr 350lbs./in * Official Ford 302S manual
Suspension Techniques/KW V1/2/3: Ft. 342lbs./in Rr 200lbs./in * KW confirmed. Rates are @ static load/ride height
Whew! The list is mind boggling. It's interesting to note the comparatively minute changes Ford made going from the base Boss to the LS as opposed to the aftermarket springs. Ford actually increased the relative stiffness of rear vs. front whereas everyone else did the opposite. You're right, though. Increasing front roll stiffness would tend tend to increase understeer which would compensate for the increased front traction of your wider tires.

Mad Hatter

Gotta go Faster
Santiago, Chile
Very happy!, Went for alignment today, with the P springs I managed to get the camber to -2.4 both sides compared to -1.9 with the stock springs. Off to a time trail tomorrow and see how they do.
Mad Hatter (ex splatter) said:
Very happy!, Went for alignment today, with the P springs I managed to get the camber to -2.4 both sides compared to -1.9 with the stock springs. Off to a time trail tomorrow and see how they do.

So you didn't have to add camber plates or panhard rod?


Mad Hatter

Gotta go Faster
Santiago, Chile
Yup, have them both, really did no like the wheel sticking out on one side! Back from the track, got first in my division and second over all, but the only cars close to my Hp in my division were a Bmw 135 and a 2013 M5. Did improve my best time at this track from 57.78 to 57.65.

Here are my first (rookie) impressions tracking the P springs

First time out I set the shocks to 5 front and back, the oversteer made the car really hard to handle and I had a nervous session with the rear breaking loose coming out of every turn. The car did not nose dive any more but the flat sensation was tricky and almost I overshot some corners as the impression of braking was quite different. 58.2 time

Second run, I put the shocks on 3 in the rear and that was much more controllable but I noticed that I was missing the late apex as the car was not turning in as quickly as before the P springs. 57.9 time

Next time out my instructor told me to but the rears on 1 to see the difference, Oddly enough it got me my fasted lap that day, though it was not very fun to drive and felt disconnected from the road. 57.65

Spent the rest of the day with 5 front 3 rear. Chasing down a new M5 was gratifying!! Even so I did loose it once with a big 180 degree spin out into the dirt. Luckily no damage done

From reading the Forum, I guess I need to get the LCA and relocation brackets to get the rear back under control. Was going to order the BMR kit (its red!) to try too keep everything within the BMR family

Fastest car that day was 53.6,,,, a honda civic with stripped out interior and 281 whp! feels funny to see a civic whizzing by you!

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