ShatterPoints
Well-Known Member
- Joined
- Apr 22, 2020
- Threads
- 3
- Messages
- 141
- Reaction score
- 115
- Location
- Austin Texas
- First Name
- James
- Vehicle(s)
- 2017 GT350
Factory is 1.3hz front and 1.5hz rear (springs) ride rate. What direction of weight transfer are you referring to? Lateral slaloms would mean a sway bar change, squat / dive would mean spring or shock change. The 350 has terminal understeer, which if you attempt to fight will throw the rest of the car off balance.yeah, it’s pretty damn well balanced for stock suspension still Needs coil overs something fierce, though. Gets overwhelmed with big weight transfers and is a bit of a pig under initial turn-in. Hoping to stiffed things up this winter.
And it puts out ~540 to the wheels on my E85 tune
I am going to change my springs to 450lbs front and ~700lbs rear or 2.0hz front and 2.2hz rear(with a rear control arm change). The factory shock motion ratio is 0.7:1 which is pretty bad, that is how we can run 914lb rear springs and 194lb springs in the front (struts are roughly 1:1 motion ratio). My rear control arm change will INCREASE the MR to 0.77:1. (Plug** https://cortexracing.com/product/co...-adjustable-2015-2019-mustang-s550-and-gt350/ )
**Edit: I was corrected by Shogun** I misspoke when I quoted the shock motion ratio. I was going by memory and not what I wrote down. The factory shock MR is 0.7:1 and it is the factory spring MR that is 0.50:1. When the rear get swapped to the aftermarket control arm AND coilovers, the new shock AND spring MR will be 0.77:1
To keep things really short, a lower MR means the shock moves in this case 70% the distance the wheel moves. The less the shock moves the less distance and as a result less time to generate the appropriate damping forces. You have to make up for this by compensating / compromising other components and end up performing band aid after jerry rig after band aid etc.
I spoke with Cortex and they have the best customer service and knowledge base of any of the aftermarket companies I have spoken with. They also run a very similar spring rate on their GT4 car, and the shock forces I came up with are very near what they run as well. You could buy their off the shelf adjustable shocks and they will suit you plenty fine. JRI is made from former penske engineer(s) and you can request dual digressive and have the adjustments on separate circuits. Else they do a default adjuster that affects low speed Compression / Rebound and then High speed Rebound only. Which means you get some cross talk but it is a fairly standard way of doing things.
These are the shock forces I have for the custom valving cortex /jri will be doing for me(note* I have to adjust the fronts to reflect a small change in high speed forces I had to make in the rear):
Front
Rear
Sponsored
Last edited: