Suspension upgrade for non-ST (sedan)

[Fish Freak]

I got the whoosh spring pads, so they're poly.

Lithium battery, spare tire and tools, and a few random bits and it'll get you there. I'm trying to drop another 20 pounds on it by end of year too.

If you get a civic si you need to get some of the newer models if you want oem front turbo. Would need the L series engine basically. The older ones would need to be either b series with an aftermarket turbo or k series but that would involve a side/ rear mount turbo.

You're getting serious with the weight reduc, which is a great idea for any car. What kinda lithium battery did you get? I had an AntiGravity batt for a motorcycle and it was amazing.

I shopped for Civic SI's a while back, but changed my mind because that 1.5 L turbo is just a little too small. It's also got a bunch of rev hang, and that's really annoying to me. Then thought the Civic Type R would be the answer, and the used market is a bit insane on those! Can't touch a clean low miles car for less than $48k out here on the left coast. For that money, I'd rather buy a 6.2L n/a Camaro SS 1Le 2SS, a far more competent track car for sure! Maybe in a few years.....

 

[WannabeST]

You're getting serious with the weight reduc, which is a great idea for any car. What kinda lithium battery did you get? I had an AntiGravity batt for a motorcycle and it was amazing.
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Antigravity, ATX 20 in the fiesta. I have an ATZ7 in my R6. Startups are faster on both, charge last longer, restart feature has never failed. I love theses batteries. Ironically my mustang is the car that needs the weight reduction the most but doesn't have one lol.

My weight reduction is fairly mild in my opinion. The interior is virtually stock besides the head unit and obd2 gauge. you can take like 200 pounds off any car without losing functionality if you try. I'll probably gut this thing eventually too.

 

[Fish Freak]

Antigravity, ATX 20 in the fiesta. I have an ATZ7 in my R6. Startups are faster on both, charge last longer, restart feature has never failed. I love theses batteries. Ironically my mustang is the car that needs the weight reduction the most but doesn't have one lol.

My weight reduction is fairly mild in my opinion. The interior is virtually stock besides the head unit and obd2 gauge. you can take like 200 pounds off any car without losing functionality if you try. I'll probably gut this thing eventually too.

What kinda OBDII gauge did you get? You're right about the weight, and it makes a big difference. I'm in the process of building several lithium, well LifePO4, battery packs for my fishing boat and pony car project.

You got a mustang too? Which one? I'm building a '68 mustang coupe, got it for that exact same reason, one of the lighter weight and affordable platforms to build a street/track car. Also lets me avoid CA smog requirements.

 

[Fish Freak]

....The rear camber plates mount behind the hub in the rear. So it is a bit more involved of a process. I might just wait until a ST rear end pops up to swap them at that time so I can get rear disc as well.

Hey Wannabe, I was just (STILL) perusing the Whoosh site and happened to see this Wilwood rear big brake kit for the ST, however, there's a footnote that caught my eye: * Standard Fiesta (drum brake) rear hubs are required for installation on a 2014-2019 Fiesta ST

I'm not too sure what they meant by that, but that's something we already have, so don't junk your hubs, and/or don't pay extra for wrecked ST hubs if you want Wilwood. Looks like you'd need the ST torsion member with caliper brackets welded on if ours don't have those tabs already behind our drums....

https://whoosh-motorsports.myshopif...rake-kit-2014-fiesta-st?variant=1260080037902

 

[WannabeST]

Hey Wannabe, I was just (STILL) perusing the Whoosh site and happened to see this Wilwood rear big brake kit for the ST, however, there's a footnote that caught my eye: * Standard Fiesta (drum brake) rear hubs are required for installation on a 2014-2019 Fiesta ST

I'm not too sure what they meant by that, but that's something we already have, so don't junk your hubs, and/or don't pay extra for wrecked ST hubs if you want Wilwood. Looks like you'd need the ST torsion member with caliper brackets welded on if ours don't have those tabs already behind our drums....

https://whoosh-motorsports.myshopif...rake-kit-2014-fiesta-st?variant=1260080037902

The drum vs disc mounting is why they are different. When wilwood made that kit the ST had not come out yet. Also I think that kit does not retain rear parking brake so not good for street cars. Also most cars don't need massive rear brakes, if you look at lots of record setting time attack cars. A lot of them just have 2 piece rear rotors on stock calipers. Don't get caught over building or adding unnecessary weight.
I'm personally not interested in investing that kind of money into this chassis. I love the chassis but even an ST has it's limitations. My mustang is a 16' premium performance pack. That car is on stock performance pack suspension and it's cornering speeds are better than the fiesta even on less sticky rubber. Much more fun all around too imo.

 

[Dialcaliper]

The camber bolts in the front come as a pair. So one for each side. on the bottom of your front strut on each side there is 2 holes where the strut mounts to your knuckle. The camber bolts go on the upper of the 2 holes to allow for some more camber. I do a lot of canyon/ mountain driving on top of track days so I keep the same alignment all the time. I read good reviews online with the triple c bolts and I have zero complaints. I would recommend them.

For the rear spring pads, I ordered ones that are the same size as stock. There should be no ride height change. I got them because my oem ones are starting to tear apart. I noticed this when I did my rear pads. Hopefully this will result in the rear end feeling more firm. Haven't installed yet to confirm.

The camber plates in the rear I also have not installed yet. I'm waiting until after my track day this weekend to see what my rear tire wear looks like. The rear camber plates mount behind the hub in the rear. So it is a bit more involved of a process. I might just wait until a ST rear end pops up to swap them at that time so I can get rear disc as well.

I have the H&R Triple-C camber bolts up front, and I highly recommend them. They are far beefier than the typical crash bolts, and I'd even trust them for light track duty, as they have a full diameter thread (M12) compared to the reduced M10 size camber bolts. They don't come with a torque spec because apparently they just expect you to torque them the same as normal M12 strut bolts (per factory manual), but since that doesn't work with our torque-to-yield bolts, I torqued them to 90 ft-lb (which is spec for a standard M12 10.9 bolt).

Not quite as good as real camber plates, but a solid alternative and much more trustworthy than the crappy traditional crash bolts.

The only downside to them is a) they're a bit of a bear to get in the hole, and b) they don't allow quite as much camber adjustment as the reduced diameter bolts. At stock ride height I was able to get about -2.0deg of camber in the front (about -1.5 from stock) with one maxed out and the other adjusted to match. Enough for the bare minimum to run a 200TW tire properly

 

[Fusion Works]

For Reference the B6 and B8 dampers use the same valving, the B8 is 1in shorter. With a shorter spring, I don't think you will seen much difference in either damper. Theoretically you can get a bit more "preload" on the spring so you might see slightly less ride height drop with the B8, but its probably within the noise. Either way you won't be un happy with the Swifts and the Bilstein dampers.

 

[M-Sport fan]

Theoretically you can get a bit more "preload" on the spring so you might see slightly less ride height drop with the B8, but its probably within the noise.

This is what I am hoping for if I go with this setup.

 

[Dialcaliper]

For Reference the B6 and B8 dampers use the same valving, the B8 is 1in shorter. With a shorter spring, I don't think you will seen much difference in either damper. Theoretically you can get a bit more "preload" on the spring so you might see slightly less ride height drop with the B8, but its probably within the noise. Either way you won't be un happy with the Swifts and the Bilstein dampers.

The change in preload from the damper shaft length won’t change the ride height at all as the damper shaft isn’t “in” the spring stack.

You have to either change the length of the spring stack, or move the lower perch. The reason motorcycles call it “adjusting preload” is because they’re just adjusting the lower spring perch without a tender spring the same as you would to adjust a car’s ride height using threaded coilover perches.

If you actually wanted to lift up the car a bit on swifts you could also add “spring rubbers” in the “dead” coil section, which won’t affect the main spring rate

 

[Fusion Works]

If you take a spring that is 13 in long for example and put it on a B6 strut and you can hand assemble those components and tighten the nut at the shaft with say 50lbs of spring force at full extension.

Now you take that same spring and put it on a B8 damper (which is 1in shorter) and it requires the use of a spring compressor to get the shaft nut started, you end up compressing that spring while installing it such that say you have 200lbs of static force at full damper extension

If it takes 250lbs per spring/damper to hold the car at ride height when you let the car down on the ground, you will have more compression to reach that 250lbs out of the B6 combo than you will out of the B8 combo. Thus the B6 combo will sit lower than the B8 combo. I have seen this on my own car.

 

[Dialcaliper]

If you take a spring that is 13 in long for example and put it on a B6 strut and you can hand assemble those components and tighten the nut at the shaft with say 50lbs of spring force at full extension.

Now you take that same spring and put it on a B8 damper (which is 1in shorter) and it requires the use of a spring compressor to get the shaft nut started, you end up compressing that spring while installing it such that say you have 200lbs of static force at full damper extension

If it takes 250lbs per spring/damper to hold the car at ride height when you let the car down on the ground, you will have more compression to reach that 250lbs out of the B6 combo than you will out of the B8 combo. Thus the B6 combo will sit lower than the B8 combo. I have seen this on my own car.

B6/B8 have the same lower perch height, and as soon as the weight of the car pushes the spring past the droop of the strut, the 13” spring will be compressed to the *same* final length based on the spring rate. Preload doesn’t change ride height unless you adjust from the bottom or add spacers at the top

The only difference is that the strut body where the bumpstop sits ends an inch lower. What I did observe with the Stock vs Mountune springs on stock struts is that the stock front springs make the car sit about 1/2”-3/4” above the soft nose of the bumpstop. The lowering springs caused the car to actually sit into the bumpstops at static ride height, which adds about 100-120lb/in to the spring rate.

What you’re probably observing is that with the B8’s, the inch lower strut body means the car isn’t sitting on the bumpstops, so sits slightly lower.

 

[Fish Freak]

B6/B8 have the same lower perch height, and as soon as the weight of the car pushes the spring past the droop of the strut, the 13” spring will be compressed to the *same* final length based on the spring rate. Preload doesn’t change ride height unless you adjust from the bottom or add spacers at the top

The only difference is that the strut body where the bumpstop sits ends an inch lower. What I did observe with the Stock vs Mountune springs on stock struts is that the stock front springs make the car sit about 1/2”-3/4” above the soft nose of the bumpstop. The lowering springs caused the car to actually sit into the bumpstops at static ride height, which adds about 100-120lb/in to the spring rate.

What you’re probably observing is that with the B8’s, the inch lower strut body means the car isn’t sitting on the bumpstops, so sits slightly lower.

Hey Dialcaliper, thanks for this info, you brought up good points about B6 vs B8 and preload. I bought and am about to install B6's on my non-ST fiesta, but using stock ST takeoff springs for full suspension travel. I noticed the foam bump stop was kinda long too, esp the rear and was concerned. You think we should shorten them? I could see this being a problem in performance driving where you're spending a lot of time on the bump stop rather than letting the suspension work the way it was designed? That couldn't be the way they it was engineered to work right? Using aftermarket Rockauto boots and bumps...

 

[Fusion Works]

It does change ride height. If I take a stock spring and put it on a stock strut I get X amount of spring force at full damper extension and then get X+ride height worth of spring force at ride height.

If I take a stock spring and put it on a B8 which has a 1in shorter shaft, I get X+1 amount of spring force over the stock spring because I have compressed that spring 1 more inch than in the OE application.

It will affect ride height, because you started with 171lbs (in the case of stock springs) more spring force at full droop on the B8 vs the B6 or even stock.

Lowering springs are even worse, if you stick a lowering spring on an OE strut you have even less force holding the car at ride height and the car sits even lower. Did that on my car as well. I started a whole thread about spring force and what measurements I have in relation to this.


You can see the stock damper vs a B8. The spring perch is in the same location, the shaft on the B8 is 1in shorter. If you take the same spring and put it on the stock damper you will have X lbs of preload. If you take that same spring and jam it on the B8 (You will have to compress it one inch more), you will have X+1in lbs of preload. X+1 will change the static ride height.

 

[Fish Freak]

It does change ride height. If I take a stock spring and put it on a stock strut I get X amount of spring force at full damper extension and then get X+ride height worth of spring force at ride height.

If I take a stock spring and put it on a B8 which has a 1in shorter shaft, I get X+1 amount of spring force over the stock spring because I have compressed that spring 1 more inch than in the OE application.

It will affect ride height, because you started with 171lbs (in the case of stock springs) more spring force at full droop on the B8 vs the B6 or even stock.

Lowering springs are even worse, if you stick a lowering spring on an OE strut you have even less force holding the car at ride height and the car sits even lower. Did that on my car as well. I started a whole thread about spring force and what measurements I have in relation to this.
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You can see the stock damper vs a B8. The spring perch is in the same location, the shaft on the B8 is 1in shorter. If you take the same spring and put it on the stock damper you will have X lbs of preload. If you take that same spring and jam it on the B8 (You will have to compress it one inch more), you will have X+1in lbs of preload. X+1 will change the static ride height.

You're right on Brett, about there being more preload on the assembled B8 strut, but won't that be negated once the resting weight of the car settles the suspension down past that 1" of extra preload? Sure there will be more static pressure pushing up on that B8 strut with it's extra preload, but push that shock down 1 1/2 inches and push the stock strut/spring down to the same place and the force graph is the same, right? At rest, the preloaded B8 starts at a higher force, then after the 1" difference, they follow the same graph. Don't ask me what that does to the parked ride height, and you have to factor the upward nitrogen pressure on the B8 too....?

What surprised me is that the B8 does not make up for the lost 1" of shaft and ride height by having a 1" lower shock body, so you're straight losing that 1" of travel in the lowered setup?

 

[Dialcaliper]

Sorry, but Fish Freak is right - the spring free length is the same, and the compressed length depends only on the weight and spring rate - shortening the shaft at the top just puts a "stopper" at a certain point of preload, and until at least that much force is applied to the shaft, the spring won't move. If you take the longer shaft shock+spring and compress 1" to match the B8 spring preload position, you'll find that the force on the spring is the same. Continue to compress both springs up to the same corner weight, and the compressed spring length will be the same = same ride height.

Any height variation you're seeing is from something else, not the preload or shock shaft length, either some tolerance somewhere, or bumpstop contact - I had also mistakenly assumed the B8 had a shorter body (where the bumpstop sits), not just a shorter shaft. I went and measured my B6's and body length (where the bumpstop contacts) also matches the stock damper.

The shorter shock shaft length then really doesn't gain you anything. The only possible function I can see for it is with "extreme" lowering springs that don't increase the stock rate, there necessarily has to be either a helper or progressive section (the tight coils) that has a low spring rate and coilbinds when the car is sitting. When the stock shock goes into droop, the helper section makes for a "looser" ride with less control because there's very little spring rate in that section. But for a very mild lowering spring, it seems like the B8 does nothing but make the shock harder to assemble.

In other words from a performance standpoint with stock or very mild lowering spring like the Swift or Mountune, the B8 is completely pointless.

"Preload" on motorcycle shocks or coilovers only adjusts ride height because you're moving the bottom perch and changing the distance from the bottom of the spring to the hub spindle, and the actual preload at droop is irrelevant to everything except for ride quality/road tracking when the shock goes into full droop.

 

[Fish Freak]

...."Preload" on motorcycle shocks or coilovers only adjusts ride height because you're moving the bottom perch and changing the distance from the bottom of the spring to the hub spindle, and the actual preload at droop is irrelevant to everything except for ride quality/road tracking when the shock goes into full droop.

That's exactly where I got my spring preload lessons: motorcycles. You can preload that spring and raise the seat height and make it 'feel' stiffer initially, but if the spring rate is unchanged, it's only a band aid. Gotta change the spring to be stiffer....

 

[Fusion Works]

Do ya'll not understand spring rate and load? If you take a spring that is Xin long and put it on a damper that is X-1 long, you will have a spring that is compressed 1in. To compress that spring 1in you will generate a force of Xlbs (What ever the rate of the spring is).

If you start with a stock Fiesta ST spring (171lbs/in), and install it on a stock damper it will have 152lbs of force pushing up against the fully extended damper. If you put that same spring on a B8 damper you will have 231lbs of force on that fully extended damper. If the damper settles at 2.5in of compression to support the weight of the car and the driver you will have 152lbs +438 lbs pushing up on the chassis. If you take that same setup with the B8 you will have 231lbs +575lbs lb you won't get that same 2.5in of drop without moving the spring perch down. You can't do that with these stock replacement dampers.

If it takes 500lbs of spring force to hold the chassis at ride height of 25in to the fender opening, if you put 650lbs of force on that spring it will lift the body up to 26in to the fender opening. If you put less force on that damper by say putting a Suspension Techniques lowering spring on that same stock strut, you only generate 115lbs of preload. Then you drop a car on it, the car will lower itself until it reaches that 500lbs of spring force. What ever the fender height is will be be lower.

This is how your drop springs work. The manufacture runs a shorter spring and sometimes a softer rate. This is why they still ride like stock or better but lower the car without moving the lower perch down.

None of the OE or drop springs are shorter than the OE shock at full droop. Therefore they will not come unseated like you can achieve with a coil over spring that can generate the required force to hold the car up without preload. A 450lb 10in coil over spring will not have any preload to hold the car up at ride height.

 

[Dialcaliper]

Do ya'll not understand spring rate and load? If you take a spring that is Xin long and put it on a damper that is X-1 long, you will have a spring that is compressed 1in. To compress that spring 1in you will generate a force of Xlbs (What ever the rate of the spring is).

If you start with a stock Fiesta ST spring (171lbs/in), and install it on a stock damper it will have 152lbs of force pushing up against the fully extended damper. If you put that same spring on a B8 damper you will have 231lbs of force on that fully extended damper. If the damper settles at 2.5in of compression to support the weight of the car and the driver you will have 152lbs +438 lbs pushing up on the chassis. If you take that same setup with the B8 you will have 231lbs +575lbs lb you won't get that same 2.5in of drop without moving the spring perch down. You can't do that with these stock replacement dampers.

If it takes 500lbs of spring force to hold the chassis at ride height of 25in to the fender opening, if you put 650lbs of force on that spring it will lift the body up to 26in to the fender opening. If you put less force on that damper by say putting a Suspension Techniques lowering spring on that same stock strut, you only generate 115lbs of preload. Then you drop a car on it, the car will lower itself until it reaches that 500lbs of spring force. What ever the fender height is will be be lower.

This is how your drop springs work. The manufacture runs a shorter spring and sometimes a softer rate. This is why they still ride like stock or better but lower the car without moving the lower perch down.

None of the OE or drop springs are shorter than the OE shock at full droop. Therefore they will not come unseated like you can achieve with a coil over spring that can generate the required force to hold the car up without preload. A 450lb 10in coil over spring will not have any preload to hold the car up at ride height.

You're missing the point. The motion until the preload is reached, there is zero shaft movement. In both cases, the stock spring has a free length of 12", which is what matters here, because that's the point that the spring is at zero force. Between 0 and preload, the shock will not move.

A 2017-2019 front spring has a rate of ~154lbs. The B6 damper has a droop spring length of ~10.625" When the B6 damper reaches 212lbs load and begins moving, the B8 with preload of 366lbs will still not have moved at all. When the B6 damper is compressed 1" to match the B8 next to it, the spring will be supporting the same 336lbs as the unmoved B8, which begins moving at that point. Another inch and both springs are supporting 521lbs, and the springs are the same compression from free length (F=-kx). When you get to the approx sprung corner weight of ~775lbs (subtracted out some for unsprung weight), both springs will be ~6.2" in length. The B6 will have moved ~4.4" from droop, and the B8 will have moved ~3.4" from its droop.

The same spring with the same force will be the same length in both cases. The only difference is the droop motion will stop at the maximum travel of the shock and the two different preloads will remain.

I'm not trying to tell you that you're dumb or don't understand physics - you seem to have a really good grasp of what's going on, its just that you're missing that the preloaded spring doesn't move. Try it with a loaded strut on a bathroom scale. You can push all you want, but until you put enough weight on it to exceed the preload, it simply won't move.

 

[Fusion Works]

You're missing the point. The motion until the preload is reached, there is zero shaft movement. In both cases, the stock spring has a free length of 12", which is what matters here, because that's the point that the spring is at zero force. Between 0 and preload, the shock will not move.

A 2017-2019 front spring has a rate of ~154lbs. The B6 damper has a droop spring length of ~10.625" When the B6 damper reaches 212lbs load and begins moving, the B8 with preload of 366lbs will still not have moved at all. When the B6 damper is compressed 1" to match the B8 next to it, the spring will be supporting the same 336lbs as the unmoved B8, which begins moving at that point. Another inch and both springs are supporting 521lbs, and the springs are the same compression from free length (F=-kx). When you get to the approx sprung corner weight of ~775lbs (subtracted out some for unsprung weight), both springs will be ~6.2" in length. The B6 will have moved ~4.4" from droop, and the B8 will have moved ~3.4" from its droop.

The same spring with the same force will be the same length in both cases. The only difference is the droop motion will stop at the maximum travel of the shock and the two different preloads will remain.

I'm not trying to tell you that you're dumb or don't understand physics - you seem to have a really good grasp of what's going on, its just that you're missing that the preloaded spring doesn't move. Try it with a loaded strut on a bathroom scale. You can push all you want, but until you put enough weight on it to exceed the preload, it simply won't move.

I don't disagree with you on the preloaded spring. It won't move until you overcome the force of the compressed spring.

Apparently we are talking past each other.

The discussion only refers to ride height. The question is does ride height change if you use the same spring on two different dampers? B6 vs B8. I claim that B8 damper with the stock spring will have a higher ride height than the B6 damper with the same spring. You claim that it won't?

 

[Dialcaliper]

I don't disagree with you on the preloaded spring. It won't move until you overcome the force of the compressed spring.

Apparently we are talking past each other.

The discussion only refers to ride height. The question is does ride height change if you use the same spring on two different dampers? B6 vs B8. I claim that B8 damper with the stock spring will have a higher ride height than the B6 damper with the same spring. You claim that it won't?

All other things being equal (damping, gas pressure, lower spring seat location), I'm claiming that just changing the "starting" shock shaft length by an inch will not change the ride height once the damper compressed to the operating range of its stroke.

If there *is* a difference in height between the two, there has to be some other difference between B6/B8 besides the shock shaft, or else some manufacturing variation between the dampers you have, like maybe lower gas pressure. You could try measuring the initial gas force required to begin moving the shocks you have (B6/B8/Stock?) - it may be different if you are in fact seeing a ride height change just from shocks, either from variation from the factory, or leakage over time, if say your B6's are significantly older.

If you look at the spring stack that holds the car up off the ground, you'll see that it goes like this:
1) Wheel/Tire
2) Hub/Knuckle
3) Lower shock body to lower spring seat
4) Compressed spring
5) Top hat/bearing/strut tower

The bumpstop and shock shaft are in parallel with that stack. The only way the shock shaft can affect the static height is by reducing the load on the spring via gas pressure. That's it. If not for the fact that it would become laterally unstable, with the car sitting on the ground, you could unbolt the shock shaft at the top, and push it down using only the force needed to overcome gas pressure (the valving contributes nothing when the piston isn't moving), nothing more. If there were zero gas pressure in the shock, the ride height wouldn't change at all with the damper completely disconnected. Doesn't matter what the shock shaft length starts out as.

If you're really curious and want to break out "SCIENCE", you could do this experiment on the rear axle because its more stable (the spring and damper are divorced so it makes a conceptually better example). Keep the wheels on, remove the rear shocks completely and lower the car onto the springs.

The only change in static height will be from the gas force in the shocks, which you could measure and subtract out from your ride height measurement, or do something clever like measure the gas force and put equal weights in the trunk near the rear shock towers (but only when the shocks are installed to cancel out the gas force, and offset by the motion ratio, which is about 1.2).

You can even drive it around like this, and you'll find that the ride quality will actually be pretty good with zero high speed damping, until you make a hard turn or go over a big whoop that makes the car body move or bounce (at which it will be pretty bouncy)