S550 Educate Me on Spring Rates

[Ewheels]

I'm looking to enter the world of coilovers soon and I need some advice on spring rates.

I'm currently on BMR springs with Ford Track shocks which are 250 lbs front and 980 lbs rear. I enjoy this setup a lot but it is still quite soft for track use.
I haven't quite decided on which coilover brand to go with but almost all of them offer custom spring rates. My only baseline is what Vorshlag offers. For their Ohlins kit, it's 500# front and 800# rear in the divorced location or their MCS spring packages (450F/550R, 600F/750R, 800F/1100R).

At the start, I'd be without aero but the plan is to add some down the road (9Lives wing and balanced DIY front splitter). I was thinking something around the Ohlins rates would be a good starting point (500/800) but it has me confused. If my current rates are 250/980 and this stiffer setup is 500/800, that would be double the rate in the front but softer in the rear....wouldn't I want stiffer in the rear as well?

 

[flyhalf]

A real rear coilover is different than oem spring rear position.
So the 980 you have is less than the 800 of the coilovers. (cause the lever difference)
I went 500 650 to start. And i liked it to start
Then when u add aero... well it changes depends on what aero.
You can "play with the sway bars" to adjust that rate on turns.

It is not a plug and play in my opinion. It requires fine tuning. Dont be surprise if you are slower at the begining.
But Here my personal advice tho.
I would get faster before moving to coilovers honestly.
You got still a nice room of improvement. My concern is with coilovers you have to ..."start again" but with 4000$ less
And with 4000$...you know how many lap analysis you can get to get faster?
But i understand that coilovers will be soon in your world. But i hope you dont dislike my italian 2 cent
Ale.
Ps. What sway bars are you still running?

 

[Ewheels]

Ale, your advice is always welcome I'm eager to learn from the best.

So for your first comment: the 500/800 is in the OEM divorced location so same lever arm as what I have now.

I know coaching and more practice are what I really need and I will continue to do so but rather than following the most optimal path, I find myself saying "F it" and build my dream car and enjoy it for what it is. I know I'm far from the fastest driver out there so might as well make the car how I want, have fun with it, and continue growing along the way.

Still on your hand-me-down sway bars. BMR front and 350R rear.

 

[SMGDHG]

A real rear coilover is different than oem spring rear position.
So the 980 you have is less than the 800 of the coilovers. (cause the lever difference)
I went 500 650 to start. And i liked it to start
Then when u add aero... well it changes depends on what aero.
You can "play with the sway bars" to adjust that rate on turns.

It is not a plug and play in my opinion. It requires fine tuning. Dont be surprise if you are slower at the begining.
But Here my personal advice tho.
I would get faster before moving to coilovers honestly.
You got still a nice room of improvement. My concern is with coilovers you have to ..."start again" but with 4000$ less
And with 4000$...you know how many lap analysis you can get to get faster?
But i understand that coilovers will be soon in your world. But i hope you dont dislike my italian 2 cent
Ale.
Ps. What sway bars are you still running?

I second everything that was said here, $6k worth of coilovers and cortex goodies made me exactly 0.0s faster until I got enough seat time to dial in the setup. I will agree with what the italian stallion says here and say spend the money on seat time

 

[flyhalf]

Ale, your advice is always welcome I'm eager to learn from the best.

So for your first comment: the 500/800 is in the OEM divorced location so same lever arm as what I have now.

I know coaching and more practice are what I really need and I will continue to do so but rather than following the most optimal path, I find myself saying "F it" and build my dream car and enjoy it for what it is. I know I'm far from the fastest driver out there so might as well make the car how I want, have fun with it, and continue growing along the way.

Still on your hand-me-down sway bars. BMR front and 350R rear.

I understand. I would go with real coilovers also on the rear.
The adjustments are on compression ,the rebound, ride height ,spring rate and sway bar rate. Might take sometime.

 

[KazarS197]

Funny how this work. I just PM d Sal a suspension question and got my answers here! I definitely need to learn much more before making any suspension changes.

 

[Fabman]

Agree…completely with Alissandro. Fundamentals first, breaking the bank comes after.

 

[biggsy]

I'm looking to enter the world of coilovers soon and I need some advice on spring rates.

I'm currently on BMR springs with Ford Track shocks which are 250 lbs front and 980 lbs rear. I enjoy this setup a lot but it is still quite soft for track use.
I haven't quite decided on which coilover brand to go with but almost all of them offer custom spring rates. My only baseline is what Vorshlag offers. For their Ohlins kit, it's 500# front and 800# rear in the divorced location or their MCS spring packages (450F/550R, 600F/750R, 800F/1100R).

At the start, I'd be without aero but the plan is to add some down the road (9Lives wing and balanced DIY front splitter). I was thinking something around the Ohlins rates would be a good starting point (500/800) but it has me confused. If my current rates are 250/980 and this stiffer setup is 500/800, that would be double the rate in the front but softer in the rear....wouldn't I want stiffer in the rear as well?

I was curious about Ohlins rates too. doesnt make sense to me but everybody that I know who runs it uses their rear spring still. I guess the 800 in the rear is the “Road” part of “Road and Track”

 

[bnight]

I was curious about Ohlins rates too. doesnt make sense to me but everybody that I know who runs it uses their rear spring still. I guess the 800 in the rear is the “Road” part of “Road and Track”

Since I do own the Ohlins and this was my first set of coilovers as well I guess I can chime in.

The Stiff front / Soft rear is a very good setup for a few reasons.

You need more spring upfront because the Mustang have more weight upfront and also to make the car handle that front better and ultimately turn better think what Max Verstapen is doing with his car setup (he prefer a lot of front rate as well).

The soft rear spring allow you to put the power down easier on the corner exits. My car is very planted on corner exits with allow me to put the pedal down and not worry about rear moving. Yet because of the hard front when you trail brake or transfer weight forward it's enough for the rear to move but not been unpredictable which allow for nice rotation around corners. This with treaded tires though. I guess with full on slick tires this spring rates will be on the softer side of things.

There were a few other reasons why I chose Ohlins:
1. They are 1 way adjustable (rebound only) that way it's harder to adjust yourself out.
2. They work with stock style strut and shock mounts which make them easy to install from normal shops.
3. They are ride height adjustable which allow for play with how the car sits and corner balance.
4. They were easier to source.
5. They are monotube and inverted on the front.

For a first set of coilovers you want to go with 1 way adjustable as it's easy to gasp the concept of adjustability. You can always upgrade down the road to a better set when you know what you are doing also the Mustang don't care about compression so Rebound is enough to set it up properly. Hope this helps.

 

[blacksheep-1]

Since I do own the Ohlins and this was my first set of coilovers as well I guess I can chime in.

The Stiff front / Soft rear is a very good setup for a few reasons.

You need more spring upfront because the Mustang have more weight upfront and also to make the car handle that front better and ultimately turn better think what Max Verstapen is doing with his car setup (he prefer a lot of front rate as well).

The soft rear spring allow you to put the power down easier on the corner exits. My car is very planted on corner exits with allow me to put the pedal down and not worry about rear moving. Yet because of the hard front when you trail brake or transfer weight forward it's enough for the rear to move but not been unpredictable which allow for nice rotation around corners. This with treaded tires though. I guess with full on slick tires this spring rates will be on the softer side of things.

There were a few other reasons why I chose Ohlins:
1. They are 1 way adjustable (rebound only) that way it's harder to adjust yourself out.
2. They work with stock style strut and shock mounts which make them easy to install from normal shops.
3. They are ride height adjustable which allow for play with how the car sits and corner balance.
4. They were easier to source.
5. They are monotube and inverted on the front.

For a first set of coilovers you want to go with 1 way adjustable as it's easy to gasp the concept of adjustability. You can always upgrade down the road to a better set when you know what you are doing also the Mustang don't care about compression so Rebound is enough to set it up properly. Hope this helps.

I would agree, you can tune yourself right out of the setup if you're not careful. Also, on a street car, you can look forward to servicing those coil over every 20K miles. As much as the guys running the $10K Penskes maintaining their cars, they still routinely run them on shock dynos to check them, and ( at least with Penskes) adjust the internals. I always prefer the dumbed down off the shock stuff from Ford Performance because it simply works well with the 95% of us who will never be able to take advantage of all the features coil overs have to offer
Going the coil over route is akin to taking the red pill.. or was it blue?

 

[SlowstangGT]

A real rear coilover is different than oem spring rear position.
So the 980 you have is less than the 800 of the coilovers. (cause the lever difference)
I went 500 650 to start. And i liked it to start
Then when u add aero... well it changes depends on what aero.
You can "play with the sway bars" to adjust that rate on turns.

It is not a plug and play in my opinion. It requires fine tuning. Dont be surprise if you are slower at the begining.
But Here my personal advice tho.
I would get faster before moving to coilovers honestly.
You got still a nice room of improvement. My concern is with coilovers you have to ..."start again" but with 4000$ less
And with 4000$...you know how many lap analysis you can get to get faster?
But i understand that coilovers will be soon in your world. But i hope you dont dislike my italian 2 cent
Ale.
Ps. What sway bars are you still running?

@flyhalf How much adjustment to your driving did you have to do once you switched to coilovers and 500/650? Those rates are in the ballpark of the coilovers I'm thinking about getting

 

[flyhalf]

@flyhalf How much adjustment to your driving did you have to do once you switched to coilovers and 500/650? Those rates are in the ballpark of the coilovers I'm thinking about getting

For sure it wasn't a plug and play thing.
Not for the spring rate though. But for compression and rebound regulation.
I like a softer car. Softer car i feel is faster for me. When i did use it for the first time all were like " u need stiff to go fast" so stiffer rebound stiffer compression stiffer springs.
Result : i was slower and most important I COULDN'T FEEL MY CAR ANYMORE.
So my advice is
Test the car first in the street. If you feel bu bouncing around.. play with rebound and compression .
And first 2 days at the track you should use to fine tune them.
Start all soft and move up is my advice.
Or all stiff and move down.
Do initially big changes ( few clicks) and then tune it with fewer adjustments. Hope it makes sense.
Last
Coilovers cannot be separated with sway bars.
A stiffer spring can help u control aero better on the straight while u can play with sway bar to increase corner spring rates

Excited for you!

 

[SlowstangGT]

For sure it wasn't a plug and play thing.
Not for the spring rate though. But for compression and rebound regulation.
I like a softer car. Softer car i feel is faster for me. When i did use it for the first time all were like " u need stiff to go fast" so stiffer rebound stiffer compression stiffer springs.
Result : i was slower and most important I COULDN'T FEEL MY CAR ANYMORE.
So my advice is
Test the car first in the street. If you feel bu bouncing around.. play with rebound and compression .
And first 2 days at the track you should use to fine tune them.
Start all soft and move up is my advice.
Or all stiff and move down.
Do initially big changes ( few clicks) and then tune it with fewer adjustments. Hope it makes sense.
Last
Coilovers cannot be separated with sway bars.
A stiffer spring can help u control aero better on the straight while u can play with sway bar to increase corner spring rates

Excited for you!

@flyhalf I fully agree with soft! The BMR/FRPP setup was an amazing setup to learn from, and still decently forgiving to mistakes in the learning process - It's a shame the front 250 springs are too soft for aero

Great advice to set the shocks to soft first! Any advice for sway bar initial settings? Did you keep the BMR front bar or switch over to Eibach?

@Ewheels it's a great coincidence you brought up Ohlins! I'm interested them but with 500/1300 (divorced rear spring) - I've sent Ohlins an email asking if I need them revalved for the higher rear spring - I can keep you posted

Ohlins should be a good first step for mild aero without shelling out $$$ for the fancy JRZ or MCS with remote reservoirs - I'll have more money for Racers360 coaching

 

[SlowstangGT]

Follow up on Ohlin's response:



It's wild they state it can handle such an extreme range! I'll most likely pull the trigger on them
Worst case - if I find the rebound is overpowered by the spring, I'll do a re-valve

 

[bnight]

Follow up on Ohlin's response:

View attachment 90628

It's wild they state it can handle such an extreme range! I'll most likely pull the trigger on them
Worst case - if I find the rebound is overpowered by the spring, I'll do a re-valve

Not sure what setting he is talking about but this is what I gathered from them when I was buying:



So if I understand correctly 650/1200 should work fine with stock valving on the FOS MR00 kit.

 

[biggsy]

Not sure what setting he is talking about

I think by “setting“ he is referring to the current valving set up.
That’s positive news though. Can make it more “track” and less “road” lol.

 

[bnight]

I think by “setting“ he is referring to the current valving set up.
That’s positive news though. Can make it more “track” and less “road” lol.

it's not exactly road with current settings as well. People see the 800 rear springs and think road setup. What they fail to see is the 515 front springs this makes the car razor sharp in cornering. From the "budget" coilovers Ohlins is a very good deal. Surely it could be better but for the money is amazing. And since now solutions like steeda ride height kit exists fixing the RLCA issues for this kit it makes for very good kit. I'm really happy how my car is "track" focused considering I have better cornering times than BMW M2's and Cayman's. This is great kit for starters as the single adjustment is good enough to learn on it. And with such valving it will allow you to grow to the next level (aero and slicks) before looking for better Dumpers and probably just in time for when they will be for rebuild anyway.

 

[SlowstangGT]

it's not exactly road with current settings as well. People see the 800 rear springs and think road setup. What they fail to see is the 515 front springs this makes the car razor sharp in cornering. From the "budget" coilovers Ohlins is a very good deal. Surely it could be better but for the money is amazing. And since now solutions like steeda ride height kit exists fixing the RLCA issues for this kit it makes for very good kit. I'm really happy how my car is "track" focused considering I have better cornering times than BMW M2's and Cayman's. This is great kit for starters as the single adjustment is good enough to learn on it. And with such valving it will allow you to grow to the next level (aero and slicks) before looking for better Dumpers and probably just in time for when they will be for rebuild anyway.

That is EXACTLY my plan! By the time a rebuild is due, I may revalve/respring or dish out the $$$ for JRZ/JRI/MCS/Penske/etc.
I can't justify those until I become a better driver though

Ohlins should live up to their reputation though; from my own personal anecdotal observations, they seem to be THE most popular coil-over in the S2K community for people who track frequently but still put in a decent amount of street mileage

 

[SlowstangGT]

@bnight QQ: I believe you are choosing the 650/1200 rates per Kenny Brown's suggestions. Do you know what sway bar those rates pair well with?
I've spreadsheeted those rates, and they shift the front roll couple quite far forward - about ~65% compared to the ~60% target I was going for with 500/1300.

I know youre on the Ohlin stock springs (500/800) right now too, and with your Steeda ARB's, that puts you at around ~70% front roll couple.
You've said in the past that the damper rebound settings do help the car rotate on turn-in, but shouldn't you [in theory] be experiencing steady state understeer?

I know there's probably some different settings for different tracks, and different driving styles throw a wrench into the mix too though - I'm not sure how much I should be focusing on this lol
Vehicle kinematics is a complex topic

 

[bnight]

@bnight QQ: I believe you are choosing the 650/1200 rates per Kenny Brown's suggestions. Do you know what sway bar those rates pair well with?
I've spreadsheeted those rates, and they shift the front roll couple quite far forward - about ~65% compared to the ~60% target I was going for with 500/1300.

I know youre on the Ohlin stock springs (500/800) right now too, and with your Steeda ARB's, that puts you at around ~70% front roll couple.
You've said in the past that the damper rebound settings do help the car rotate on turn-in, but shouldn't you [in theory] be experiencing steady state understeer?

I know there's probably some different settings for different tracks, and different driving styles throw a wrench into the mix too though - I'm not sure how much I should be focusing on this lol
Vehicle kinematics is a complex topic

Yeah I'm targeting Kenny Brown's 650/1200 suggestion he use this on his JRZ RS Pro's for cars with Slicks and some aero but not to extreem with real aero he is jumping to 800 front springs, you have to consider that the GT4 use 750 lbs front springs as the hardest spring possible. He uses Eibach swaybars so you can imagine my Steeda sway is good enough.

My tracks are very slow fastest one of them is Serres (fastest corner is 140 km/h) there I even experienced oversteer with my current settings. Car is very precise at the moment and I like how balanced it is also a little understeer (which I lack) in fast corners is a good thing as it gives you more control. My lap time on that track dropped by over 7 seconds but the track was newly repaved.

However car balance as well shock settings are really personal thing I find out early on in my drivers journey that I need a balanced car but I also need body roll as this gives me more feedback (the downside of two season on stock suspension I guess). With all that in mind what I was more concerned when installing the Ohlins was that I wouldn't be able to strike that neutral car balance I was having with the stock setup. I'm happy to report that this was not the case and the car is mind blowing to drive it gives me enough feedback is razor sharp and even over the limit super easy to control.

Naturally my lap times dropped a lot in fact they dropped by almost 4 seconds on my local track (2km in lenght) from 1:09.774 (with stock suspension 275 tires) to 1:06.39 (with Ohlins and 305 tires) this is a big improvement. Something that I didn't mention is that the steeda IRS base kit actually dropped 0.5 sec of this times as it helped me in left/right transitions which my track has 2 of them. So steeda products actually work.

I need to mention that I'm running into a new issue with my setup though which is a knock over some bumps and when turning the wheels. My dealer explained that this was the right side shock and by the look of it should be the spring insulator which is the only OEM part still left in the setup turns out they do have a bearing in them that goes bad eventually and mine do have a lot of time on them. It's cheap part but a PITA to replace.