INDY Springs by MRP Racing:
For the Road Racing fan, MRP Racing offers it's full line
of INDY springs.
The Indy springs are great quality and MRP's special attention
to road racing makes them one of the best choices around.
One important note is that with MRP recommends also using
FMS or Global West lower control arms with
their springs. The Indy-GW combo is one of the simplest and most effective
suspension for road racing and will not cost you big bucks like other
setups with pan hard rods or IRS.
MRP offers several rates for all mustang models:Y
79-PRESENT Mustang Springs Rates/Kits
| FRONTS Spring Kit
/Rates |
REARS Spring Kit /Rates |
| Indy-006
600lbs |
Indy-061 160lbs |
| Indy-086 680lbs |
Indy-071 170lbs |
| Indy-008 800lbs |
Indy-091 190lbs |
| Indy-529 925lbs |
Indy-512 215lbs |
The Spring rate you select will depend a lot on the actual
use of your car, if its mostly street then a softer front and stiffer
rear is desirable but wont be the best for road racing. 700/170 springs
are recommended by MRP for street use, while the 800 or 925 fronts
with 160s in the rear.
INSTALL
REAR SPRINGS:
Place car on jack stands,
the car should be lifted from the frame so that the axle is free to
hang down. Remove the rear wheels, the quad shock bolts on the axle
side and the pinion snubber. (discard)
Place another jack on the
rear axle differential housing and raise it. Now remove the axle side
shock bolts and nuts. Loosen the upper arms differential side bolts
and remove, this will allow the differential to drop completely and
makes it easier to remove the springs.
Lower the jack at the differential and remove the springs.
Be careful not to lower the rear too much or you can break the rear
brake line that sits at top of the differential case.
NOTE: Remove the lower arm-to-axle
pivot bolt and nut if the springs wont come out or use a spring compressor.
Put the springs back in place. Now raise the differential
to align the lower arms to the axle mounting points.
FRONT SPRINGS: (pics soon)
This is the tough part, you will most probably need a spring
compressor so go buy or rent one. On our project car we had EIBACH
1.5 lowering springs so removing them was done without a spring compressor.
Raise the front on jack stands.
If using a compressor place a jack under the Lower arm and
raise it, now compress the springs to get them out.
If you don't have a compressor place a jack under the Lower
arm. Remove the wheels and lower the jack under the lower arm, now
remove the sway bar links and front struts. The steering tie
Rod ends should also be removed from the spindle to make the job easier.
You might have to use a crow bar to remove the spring. At this point
BE VERY CAREFULL, make sure the spring is FULLY EXTENDED, if not it
could jump out of the perch and hit you....and trust us IT WILL HURT.
Reverse for install.
Final Comments
The car was lowered 1" with the Indy Springs, so it is
taller than with the 1.5 Eibach's and our final combination consists
now of Global West LCA's and Indy Springs, shocks and struts are still
stock. This is not the best combination because the rear is a bit
too soft for the stock shocks, but trust us, its a lot better than
stock. A complete setup should include either KONI DAs or at least
Tokicos adjustable's or Bilsteins.
Now about the ride, the front is STIFF, but it doesn't feel
that bad with the 700 rate linear springs, the rear feels softer but
its not bouncy, here the Global West arms contribute to the rear end
stability.
Our first road tests show that the car is a lot more predictable,
and on uneven roads the front wont bounce as with the Eibachs, the
rear end hooks great with no fishtailing or over steer. The car in
general is pretty much neutral, when with the Eibachs it was
a bit unpredictable, it over steered or under steered depending on
road conditions.
The setup is far from perfect yet, adjustable struts/shocks
should go next, and will also need front arm bushings and CC
plates to get the correct caster/camber/toe settings.
