Advice for autox HS shocks. Can only find rear Koni yellows....

[M-Sport fan]

Does anyone know just how much spring rate the upper rebound range of the standard Fiesta Koni Sport fronts can handle without revalving?

 

[scotman]

Does anyone know just how much spring rate the upper rebound range of the standard Fiesta Koni Sport fronts can handle without revalving?

The only people who could answer that would be those who use linear springs​. I had very limited time on linear springs on the basic Fiesta using the front developmental yellows. 500 lb in were too much. 400 lb in were usable, but I didn't care for their behavior on the street. I think that if any Fiesta has much tire under it, the suspension really needs to be allowed to work.

 

[M-Sport fan]

The only people who could answer that would be those who use linear springs​. I had very limited time on linear springs on the basic Fiesta using the front developmental yellows. 500 lb in were too much. 400 lb in were usable, but I didn't care for their behavior on the street. I think that if any Fiesta has much tire under it, the suspension really needs to be allowed to work.

Thanks!

I would ONLY use linear rate springs, even for exclusive street use, if I am going to bother changing from the factory springs.
I do not trust progressive rate springs on turn-in, and then mid corner apex.

 

[scotman]

Thanks!

I would ONLY use linear rate springs, even for exclusive street use, if I am going to bother changing from the factory springs.
I do not trust progressive rate springs on turn-in, and then mid corner apex.

Uhh, ok. Do you understand the implications of a very stiff sidewall tire and a linear rate spring? Especially when cornering over an uneven surface?

 

[KKaWing]

Uhh, ok. Do you understand the implications of a very stiff sidewall tire and a linear rate spring? Especially when cornering over an uneven surface?

Progressive springs will react differently to the different bumps at different speeds. The linear springs will react the same way, for each and every bump, each and every time. If the car is skipping, then it is either over damped or over sprung. In short, linear springs will produce a reaction that is predictable, progressive springs do not.

And yes... you have drivers that can go fast regardless of the car so part preferences is a moot point for them. For us mortals, guessing what the car would do mid corner is beyond our capabilities.

 

[scotman]

Yup. I have found that a stiff spring and a short sidewall tire can create some undesirable Behaviors when it's driven aggressively over an uneven course or during a turn. I wouldn't use them on the street. Not even the 400lb in spring. The stability controls ( to esp on the basic Fiesta) genuinely hate a linear spring setup, even if it's just the front springs.

 

[M-Sport fan]

Progressive springs will react differently to the different bumps at different speeds. The linear springs will react the same way, for each and every bump, each and every time. If the car is skipping, then it is either over damped or over sprung. In short, linear springs will produce a reaction that is predictable, progressive springs do not.

And yes... you have drivers that can go fast regardless of the car so part preferences is a moot point for them. For us mortals, guessing what the car would do mid corner is beyond our capabilities.

+1 THANK YOU!

 

[M-Sport fan]

Yup. I have found that a stiff spring and a short sidewall tire can create some undesirable Behaviors when it's driven aggressively over an uneven course or during a turn. I wouldn't use them on the street. Not even the 400lb in spring. The stability controls ( to esp on the basic Fiesta) genuinely hate a linear spring setup, even if it's just the front springs.

The ONLY time I even have "Sport" mode enabled (let alone full ESC), is during downpours/snow/ice.

Also, there are A LOT of variations within "short sidewall tires", as some taller/higher profile sidewalls can actually be stiffer (higher effective spring rates) than some shorter/lower profile sidewalls depending on contruction/etc.

 

[scotman]

I agree. A person who is interested in making changes to the suspension and tires really needs to be aware of the effect that each change makes, and recognize the possibility of bad results coming from improper choices. On my 16 ST, I kept the stock coils and just installed Koni sport dampers all around. It's great.

 

[M-Sport fan]

I agree. A person who is interested in making changes to the suspension and tires really needs to be aware of the effect that each change makes, and recognize the possibility of bad results coming from improper choices. On my 16 ST, I kept the stock coils and just installed Koni sport dampers all around. It's great.

I was considering this as well (or Bilstein B8s IF I could live without the rebound adjustments).

But, I am willing to give up a tiny bit of wheel travel, and yes, slightly increased bump steer/'skittering' on broken pavement turns (which I crawl over anyway since I don't want to break half shafts, etc. ) to have ~ 1" lowering all around on Swift Spec R springs.

 

[scotman]

I looked at that combination as well! But, I decided to get rid of the back seat and create a light load floor, move the battery to the right rear and go with 16 inch Enkie RPF-1 wheels and a calculated fuel level for solo events. I didn't need more rate with less weight.

 

[M-Sport fan]

^^^The rear seat delete, and battery relocation, absolutely move you out of H/Street, and into one of the ST/xx (or maybe even /Street Prepared) classes, despite keeping the factory springs, correct?

 

[scotman]

Yup.it does. I have other changes in store. But first the cooling system issue has to be fixed. My plans have changed due to the problems. I planned​ to be in a street prepared class and also do some track events. But I've had to rethink the wisdom of that. I'm building a Lotus seven knockoff for tracking now. The Fiesta ST is kinda brittle.

 

[M-Sport fan]

^^^Caterham, Super Seven, something else??

 

[scotman]

Locost 442. Like a seven but 4 inches wider, 4 inches longer and 2 inches taller. The original size seven is tiny, bike engine tiny. I want room for Ecoboost/Zetec or Honda engines. I love the Fiesta ST, but it's just become too expensive to make a dual purpose car out of it for several reasons. I won't be doing anymore projects like this again. The electronic nannies and the costs are just too much. But, to stay on topic, the harsh stock suspension can be greatly improved without a huge expense.

 

[M-Sport fan]

Locost 442. Like a seven but 4 inches wider, 4 inches longer and 2 inches taller. The original size seven is tiny, bike engine tiny. I want room for Ecoboost/Zetec or Honda engines. I love the Fiesta ST, but it's just become too expensive to make a dual purpose car out of it for several reasons. I won't be doing anymore projects like this again. The electronic nannies and the costs are just too much. But, to stay on topic, the harsh stock suspension can be greatly improved without a huge expense.

Yes, for a dedicated, or mostly track car, I would still want RWD, or AWD, despite how competently, a FWD platform can be made to be competitive, and 'track worthy'.

I also will probably only take this car so far concerning track type prep/mods, as well >$15K can be EASILY spent (i.e.; carbon fiber/lightweight parts & lithium battery, 3 way adjustable coil over dampers, full-on BBKs, limited slip diff, light seats, aero, sets of light wheels/full race tires, etc. etc.) on them BEFORE one even THINKS about the power/turbo upgrades.
(And that's before the entry fees, sanctioning body dues, safety clothing/gear, and various 'consumables' for all of the above listed mods!! )

I may be the only one on this whole site (or any other FiST site?) who does not think that the factory suspension/damper valving is all that "harsh", but, that does not necessarily mean I think it is ideal/'optimal', or cannot be improved as far as response, turn-in, and overall handling performance goes, either.