Lets talk Spring Load, Not the usual Spring Rate thread

[Rhys1983]

This is where a custom valving comes into play. The "unsettled" feeling you get is a lack of rebound control. I was looking at the dyno curves last night and the OE ST rear damper has higher forces than the Bilstein B8 does. I am starting to think mixing and matching may be the answer for an off the shelf basic setup. If I can round up another ST rear damper I may swap it on to my car to see how it feels. I am rounding up some bleed shims to change the valving in my custom dampers to see if I can make it a better match for a street setup.


If you change to a base Fiesta knuckle your steering rate changes. That was one of the changes on the ST, they shortened the steering arm to make the steering quicker. I would hate to give up the quick steering on this car.

It will be interesting to see what set up you find works best for street use and finally end up with. There doesn’t seem to be a coilover set up that works any better than the standard set up or the B8 set up. The front B8’s that I have are different to regular B8 suspension as was the case with the m-sport optional handling pack, but the rear B8’s are just standard.

It would be a shame to lose the quick steering of the fiesta st as this is a big factor in it’s handling.

 

[Fusion Works]

I expect I will be using my custom valved parts, but agree that finding a solid combination for normal guys who want an improvement over the stock setup will be good.

Do your front B8s have an inverted damper or are they a twin tube with a normal diameter shaft sticking out? Would be nice to see what the curve looks like on them compared to the mass market B8s.

 

[Rutschpartie]

This is where a custom valving comes into play. The "unsettled" feeling you get is a lack of rebound control. I was looking at the dyno curves last night and the OE ST rear damper has higher forces than the Bilstein B8 does. I am starting to think mixing and matching may be the answer for an off the shelf basic setup. If I can round up another ST rear damper I may swap it on to my car to see how it feels. I am rounding up some bleed shims to change the valving in my custom dampers to see if I can make it a better match for a street setup.


If you change to a base Fiesta knuckle your steering rate changes. That was one of the changes on the ST, they shortened the steering arm to make the steering quicker. I would hate to give up the quick steering on this car.

It will be interesting to see what set up you find works best for street use and finally end up with. There doesn’t seem to be a coilover set up that works any better than the standard set up or the B8 set up. The front B8’s that I have are different to regular B8 suspension as was the case with the m-sport optional handling pack, but the rear B8’s are just standard.

It would be a shame to lose the quick steering of the fiesta st as this is a big factor in it’s handling.

you will not lose quick steering...yes the lever arm will be a bit longer, but the ratio of the steering rack itself will not change and should still be a lot "faster" than stock fiesta. Also I do not think experimenting with revalving your custom valved b8 is a good idea when you cannot even tell for sure if you need more or less rebound damping, ofc this depends on the surface you are driving on and Fusion Works may have completely different valving, driving conditions and most important: tires....

 

[Fusion Works]

you will not lose quick steering...yes the lever arm will be a bit longer, but the ratio of the steering rack itself will not change and should be a lot "faster" than stock fiesta. .

What happens when the lever arm length from center of the wheel gets longer? The actual steer ratio will be slower than one with a shorter steering arm. It was enough for Ford to create completely new knuckle for the ST compared the base models to create a "character" for the ST that was different than other cars in Ford's product line.

Also I do not think experimenting with revalving your custom valved b8 is a good idea when you cannot even tell for sure if you need more or less rebound damping, ofc this depends on the surface you are driving on and Fusion Works may have completely different valving, driving conditions and most important: tires....

The rear B8s don't have that much valving. They are softer than stock, across the range. The fronts have about 50lbs more rebound across the range in rebound and compression.

If the car "feels unsettled", that points towards a need for more rebound/chassis control. I would tell you to get a set of stock ST rear dampers and swap them in. Then drive the car. Rear dampers should take 30minutes to change. Find someone with some blingy coil overs and they will probably give you the OE ones for free.

 

[Rhys1983]

I expect I will be using my custom valved parts, but agree that finding a solid combination for normal guys who want an improvement over the stock setup will be good.

Do your front B8s have an inverted damper or are they a twin tube with a normal diameter shaft sticking out? Would be nice to see what the curve looks like on them compared to the mass market B8s.

They are inverted monotube. It would be really interesting to find out the valving and suspension curve on them compared to normal B8’s.
I have attached a photo of the m-sport edition which explains a bit about the optional handling pack. Only 20 were ever made and I believe that mine is only 3-4 which has every extra option on the car.

 

[Fusion Works]

Now I am definitely interested in what damper they used, because the B8 is a twin tube replacement shock, not an inverted monotube like your car. Need more pics of the dampers.

Also the 11mm track increase is interesting. Did they do that with spacers, or wheels?

 

[Rutschpartie]

What happens when the lever arm length from center of the wheel gets longer? The actual steer ratio will be slower than one with a shorter steering arm. It was enough for Ford to create completely new knuckle for the ST compared the base models to create a "character" for the ST that was different than other cars in Ford's product line.

I know that you want to help but you are giving advice with confidence that is not 100% correct. The steering will still be quick, you will not lose this by switching to base knuckles. The knuckle was not mainly/only designed to make steering quicker. It was designed for improved ackerman ratio, adjusted roll centre, camber increase, bump steer, damper pickup points and strength (all of this you have to measure/test/adjust when switching to base knuckles in my opinion). If you do not believe this, just do the math: simplified 2D equation for the two lever arms and the pinion movement (l1..short arm, l2..tie rod length, phi..angle, x...distance from knuckle pivot to begin of tie rod) and COMPARE it with with l2>>l1 to the effect of the quicker rack/pinion ratio. It will still be a lot quicker than the base fiesta.

 

[Rutschpartie]

If the car "feels unsettled", that points towards a need for more rebound/chassis control. I would tell you to get a set of stock ST rear dampers and swap them in. Then drive the car. Rear dampers should take 30minutes to change. Find someone with some blingy coil overs and they will probably give you the OE ones for free.

trying some stock ST dampers to see the difference is a good idea i think. It will tell you if this "unsettle" is rly lack of rebound control related, can be, but is also just a wild guess at this point...it is also possible that you need to soften your whole suspension (including springs).

 

[Rhys1983]

Now I am definitely interested in what damper they used, because the B8 is a twin tube replacement shock, not an inverted monotube like your car. Need more pics of the dampers.

Also the 11mm track increase is interesting. Did they do that with spacers, or wheels?

I know that the wheel offset is different on the M-Sport edition cars, but there may be a spacer in there as well. I did have another fiesta before this car and that had the club sport mountune kit on it which consists of B8 dampers and mountune springs. The M-Sport edition feels totally different to my old car. Much sharper and more direct and you can feel everything that’s going on with the road.
I have attached the only photo that I have of the front strut. I will try and get more info on the suspension when I take it into the specialist to set it up.

 

[Rhys1983]

trying some stock ST dampers to see the difference is a good idea i think. It will tell you if this "unsettle" is rly lack of rebound control related, can be, but is also just a wild guess at this point...it is also possible that you need to soften your whole suspension (including springs).

It’s hard for me to say exactly what’s happening. Like I said before, the car feels really good but then I don’t have the experience to know if it can be improved and where improvements can be made. Ideally, I’d like to get a suspension set up expert to drive it, take measurements and then do any adjustments that he thinks that would improve anything.

 

[Rutschpartie]

It’s hard for me to say exactly what’s happening. Like I said before, the car feels really good but then I don’t have the experience to know if it can be improved and where improvements can be made. Ideally, I’d like to get a suspension set up expert to drive it, take measurements and then do any adjustments that he thinks that would improve anything.

do exactly that it is the best way if you cannot exactly tell what could be improved. But be careful that they do not talk you into spending a lot of money for things you do not rly need. Make sure you find someone who is associated with a renowned local racing team (suspension engineer) and has the right references and not some tuning mechanic bolting on some random parts. Tell them how much you want to spend and ask them what they can do for you.

 

[Rhys1983]

do exactly that it is the best way if you cannot exactly tell what could be improved. But be careful that they do not talk you into spending a lot of money for things you do not rly need. Make sure you find someone who is associated with a renowned local racing team (suspension engineer) and has the right references and not some tuning mechanic bolting on some random parts. Tell them how much you want to spend and ask them what they can do for you.

Yes, I don’t want to spend too much on parts unless it makes a big difference.
I can’t see any other suspension set up such as coilovers that would be any be any better than what I’ve got, unless you know of any?
I’ve got the spring spacers and the DNA castor/camber control arms so that will offer some adjustments and fine tuning. There is also an option of fitting different springs such as the original st ones in the softer, post ‘16 set up.
Out of interest, @Fusion Works were your springs custom made, or can you buy them?

 

[Fusion Works]

The springs on my custom parts are all just normal off the shelf 2.5in race springs. They come in various rates from 50-3000+lbs. They are nothing special. The other springs are just off the shelf springs. OE early 16 model springs or Suspension Techniques lowering springs.

It’s hard for me to say exactly what’s happening. Like I said before, the car feels really good but then I don’t have the experience to know if it can be improved and where improvements can be made. Ideally, I’d like to get a suspension set up expert to drive it, take measurements and then do any adjustments that he thinks that would improve anything.

Another thing to keep in mind, the Fiesta ST has less rear camber than the base model. I suspect they did this to "loosen up" the car and let it rotate a little more. This would give the car a more playful feel to the normal driver. The drawback is once the car gets to a certain slip angle you lose more grip on the back than if you had a meaningful amount of negative camber on the rear. Camber adjustment is something the Fiesta is lacking and really needs when driving hard.

 

[M-Sport fan]

Now I am definitely interested in what damper they used, because the B8 is a twin tube replacement shock, not an inverted monotube like your car. Need more pics of the dampers.

Also the 11mm track increase is interesting. Did they do that with spacers, or wheels?

I never knew that they used (Motorsport spec??) inverted Bilstein fronts in that package, let alone that one could opt for those Alcon R2/R5 front brakes.

Maybe they are that 46mm (?) Motorsport Bilstein they used for the R1 cars, just with a strut spring mount attached instead of a coil over conversion perch mount?
(But the latter versions of that were threaded alloy body, not steel, like on Rhys 1983's car.)

The OZ Superturismo LM wheels included in that package were a ET40 (I believe) vs. the factory wheel's ET47.5(??), so that is almost an 8mm track increase right there, I don't know where/how they got the other 3mm+ from though (maybe the Alcon hats???).

 

[Rhys1983]

The springs on my custom parts are all just normal off the shelf 2.5in race springs. They come in various rates from 50-3000+lbs. They are nothing special. The other springs are just off the shelf springs. OE early 16 model springs or Suspension Techniques lowering springs.



Another thing to keep in mind, the Fiesta ST has less rear camber than the base model. I suspect they did this to "loosen up" the car and let it rotate a little more. This would give the car a more playful feel to the normal driver. The drawback is once the car gets to a certain slip angle you lose more grip on the back than if you had a meaningful amount of negative camber on the rear. Camber adjustment is something the Fiesta is lacking and really needs when driving hard.

You can get rear camber plates in the Uk which I’m sure you could get over there in the US. They add another 1.5 degrees camber. I think this would possibly be too much for road driving, but good on track. I’ve also heard of people using washers to gain extra camber, but I’m not sure if this is recommended!

 

[M-Sport fan]

If you change to a base Fiesta knuckle your steering rate changes. That was one of the changes on the ST, they shortened the steering arm to make the steering quicker. I would hate to give up the quick steering on this car.

True, but if you've ever seen that video I posted of the French RT2 crews practicing in the maritime mountains for one of the French National Rally Championship rounds, that did not seem to hurt them all that much, given the crazy turn-in and rotation they were getting around those switchback/hairpin/decreasing radius turns there.

Granted, yes, their cars were perfectly setup/corner weighted/balanced, rigid reinforced unibodies/cages, they have hydraulic hand brakes, and are on the equivalent of 00 tread wear, semi-slick tarmac tires.

 

[Rhys1983]

I never knew that they used (Motorsport spec??) inverted Bilstein fronts in that package, let alone that one could opt for those Alcon R2/R5 front brakes.

Maybe they are that 46mm Motorsport Bilstein they used for the R1 cars, just with a strut spring mount attached instead of a coil over conversion perch mount?

The OZ Superturismo LM wheels included in that package were a ET40 (I believe) vs. the factory wheel's ET47.5(??), so that is almost an 8mm track increase right there, I don't know where/how they got the other 3mm+ from though (maybe the Alcon hats???).

It would be good to know exactly what these struts are!
If you type m-sport edition pistonheads rewiew it’s a good read on how this car compares to the standard ST and lists the upgrades. It’s a good read when you’ve got time. I would share a link, but my computer skills are slightly lacking! However, the mention of progressive springs is incorrect as only the rear are progressive and I believe that the coils bind effectively making them behave like linear springs.
I think that the wheels are 42 ET offset. I believe that the Alcon brakes add nearly 10mm offset as well. I know that the person who had the car before me fitted some rear spacers so that the rear of the car matches the front.

 

[Dialcaliper]

It would be good to know exactly what these struts are!
If you type m-sport edition pistonheads rewiew it’s a good read on how this car compares to the standard ST and lists the upgrades. It’s a good read when you’ve got time. I would share a link, but my computer skills are slightly lacking! However, the mention of progressive springs is incorrect as only the rear are progressive and I believe that the coils bind effectively making them behave like linear springs.
I think that the wheels are 42 ET offset. I believe that the Alcon brakes add nearly 10mm offset as well. I know that the person who had the car before me fitted some rear spacers so that the rear of the car matches the front.

Interesting comments on this post - someone from Poland installed the R1 struts and shocks. Adjustment range and body diameter actually looks very similar to the B14 (1.5-2”), just black with pinspanner lockings, probably a longer strut insert with different valving. Down in the comments the OP mentions the R1 rears are divorced and non-adjustable, so the front is really only there for corner balancing

https://www.reddit.com/r/FiestaST/comments/r9vs8u View: https://www.reddit.com/r/FiestaST/comments/r9vs8u/last_rallycross_of_the_year_testing_out_newly/


Same person/car - Fiesta SE knuckles maybe not actually much different besides the alignment and steering ratio. Caliper appears to mount in the same place which agrees with what I’ve found elsewhere (The base Fiesta uses a smaller caliper/bracket than the ST)

View: https://m.youtube.com/watch?v=V6S_Xtkzmto

 

[Fusion Works]

You can get rear camber plates in the Uk which I’m sure you could get over there in the US. They add another 1.5 degrees camber. I think this would possibly be too much for road driving, but good on track. I’ve also heard of people using washers to gain extra camber, but I’m not sure if this is recommended!

Not at all. Camber doesn't wear tires, toe wears tires. I normally run -2.5-3 all the way around on my adjustable street cars. Hondas and such. My car has -2.3 on the rear currently with no wear issues. Please don't use washers, those people are idiots.

 

[Fusion Works]

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Same person/car - Fiesta SE knuckles maybe not actually much different besides the alignment and steering ratio. Caliper appears to mount in the same place which agrees with what I’ve found elsewhere (The base Fiesta uses a smaller caliper/bracket than the ST)

View: https://m.youtube.com/watch?v=V6S_Xtkzmto

So that strut is based around the 46mm universal Motorsports Strut. Those components are sadly NLA. I have talked to Bilstein recently about what parts are available and just a handful of small parts is all thats left. Its disappointing.