Fiesta ST autocross accident

[RAAM]

I see a few issues with the car setup.

1) They do not need a rear sway bar, not sure without digging into my old chassis setup books but it could likely of been a factor. As I recall a rear sway bar would transfer weight to the opposite side front tire.
2) Tires, OK, love sticky tires but....air pressure might of been to low and the next item on the list can be very critical.
3) Wheels, should be 8" wide for proper sidewall support, compounded again by air pressure.
4) Springs, I do not know the rates or if linear or progressive but could be a serious issue.
5) Dampers, also do not know how well they are valved to work with those springs.

Then the course layout and surface as well as driving style not being very smooth, all mitigating factors.

The main problem is most have very little understanding of proper geometry, the more one lowers a car the closer one gets to being to low, if the springs compress enough it can result in the majority if not all the weight being transferred to the outside tires like it does on a properly spring rate setup but lowered to much. The inner pickup points HAVE TO BE HIGHER than the ball joints center of rotation, simple physics.

The vast majority of modded cars are not setup properly, especially the absurd stance ones, cartoon setups that work for nothing about actual performance and most are quite dangerous, fact, not fiction.

Rick

 

[Snrub]

I like that RAAM has suggested multiple ways of how to be safer. I know others have eluded to it as well, there has yet to be an explicit recipe to reducing rollover risk, rather than simply not increasing it.

For instance, there was discussion of roll centers but how would one know how low is too low? Most lowering spring are progressive, is this a bad idea?

What if one wants to make the car safer than OEM? Would the safest be an adjustable coilover, or DIY setup like Dialcalipers where he used standard racing coils at a higher spring rate while maintaining ride height?

Montotune's (presumably one of the best funded engineering) springs drop the car, but barely adjust the rate. The fronts look linear, the rears look progressive.

Lots of people had dropped to 16 or 15" tires sizes with taller sidewall. Should they make different considerations than those with 17" tires?

There is another thread with shock dynos. What are the safest spring/shock matches?

I know when I've done emergency swerves, the body roll of the car makes the car far less easy to control than say my old RX-8, or my old NA Miata race car. At one point I lowered the Miata so low the control arms angled up when sitting (double wishbone front/rear, height adjustable sleeves) and I couldn't notice the mistake on the track.

 

[WannabeST]

I like that RAAM has suggested multiple ways of how to be safer. I know others have eluded to it as well, there has yet to be an explicit recipe to reducing rollover risk, rather than simply not increasing it.

For instance, there was discussion of roll centers but how would one know how low is too low? Most lowering spring are progressive, is this a bad idea?

What if one wants to make the car safer than OEM? Would the safest be an adjustable coilover, or DIY setup like Dialcalipers where he used standard racing coils at a higher spring rate while maintaining ride height?

Montotune's (presumably one of the best funded engineering) springs drop the car, but barely adjust the rate. The fronts look linear, the rears look progressive.

Lots of people had dropped to 16 or 15" tires sizes with taller sidewall. Should they make different considerations than those with 17" tires?

There is another thread with shock dynos. What are the safest spring/shock matches?

I know when I've done emergency swerves, the body roll of the car makes the car far less easy to control than say my old RX-8, or my old NA Miata race car. At one point I lowered the Miata so low the control arms angled up when sitting (double wishbone front/rear, height adjustable sleeves) and I couldn't notice the mistake on the track.

Track day insurance is always an option, but motorsports by nature are very risky and unsafe. We can obviously mitigate risk with modifications and safety equipment but no amount of modifications or equipment will change the fact that you are still tossing around a big chunk of metal. Rollover risk aside, any car can have a failure from stress or fatigue at any moment, which can lead to a bad accident. The Fiesta is still one of the worst cars (safety rating wise) to own. If one cars that much about their safety they should consider a different chassis or they should consider the fact that motorsports is not for them.

 

[Snrub]

^ That amounts to saying trying is the first step towards failure. It's common when building a racer car to consider things that make the car safer, so why not consider it as part of this discussion?

 

[foodtruck]

Well, if you want to race your car but make it safe,

1) Use high-treadware tires (300+)
2) Make sure car has a significantly wider average wheel track than it is higher (main SCCA solo eligibility rule criteria)
3) Make sure it has more traction in the rear than in the front so that it understeers rather than oversteers at the limit

But you have to make peace with the fact that it wont be the most exciting car to race 🤷🏻‍♂️

For everything else, you probably need a team of engineers and complex simulation software to be certain (which is probably why the common advice is to not mess with the formula provided by, you know, a team of engineers and complex simulation software at the company that built the car)

 

[Intuit]

.... (which is probably why the common advice is to not mess with the formula provided by, you know, a team of engineers and complex simulation software at the company that built the car)

I'm beginning to think that some of this may not just be the arrogant presumption of being better than the teams of engineers behind the product; or simple ignorance of the potential consequences of mishandling a misconfigured a vehicle.

Even after some of these folks are informed, they still continue to resist the idea that their changes and driving behaviors had anything to do with the wreck.

There were posters here who'd make changes to the programming and/or engine then try to warranty it with Ford following an engine failure. Some would complain because their claim was denied.

I remember a post where someone was railing against Ford for having sold a lemon because they refused to warranty his wife's clutch with physical damage... two or three times.

Then we have someone here, (and this is the only case we've seen thus far,) who's buddy redoes much of the suspension system, crashes it... but rather than blame his buddy, blames Ford.

What does all of this have in common?

A complete avoidance of any and all responsibility.

 

[jmrtsus]

I did not buy a small performance car to be safe when judged with large heavy vehicles like trucks and SUV's. I have been delighted with the stock handling and MP-215 on my car. Anyone is free to experiment with suspension changes but with that comes the risk of screwing it up. You get no crying towels for overcooking the omelet so to speak. Was it Dirty Harry that said something about "knowing your limitations"? Many people in life exceed thiers once too often. I did that years ago with my dirt bike, sold it 6 months later.......just plain lost the balls I once had driving it. Pain changes folks sometimes, did me!

 

[SteveS]

The Fiesta is so unsafe for racing that the British have two racing series for it--including one for the most junior drivers.
https://brscc.co.uk/formulae/fiesta-junior-championship/
https://brscc.co.uk/formulae/airtec-motorsport-fiesta-st240-championship/

 

[Snrub]

There's no reason to get our backs up about this conversation. Why is it a challenge to discuss how to make good modifications? Eg. What ride height do they use in the BRSCC series?

 

[foodtruck]

Why is it a challenge to discuss how to make good modifications?

For me, it's because the definition of "good" varies depending on what you want to achieve. Some changes that improve on a certain quality and thus considered "good" also often bring a detriment in another quality, so they're also "bad" at the same time. A simple example would be solid mounts for everything (good steering/response, bad NVH), but oftentimes its not as clear cut, which is why I said what I said earlier. In case of suspension, you can introduce weird resonances that might severely upset the car in an unsafe way (disclaimer: I'm not an automotive engineer, but resonances and positive feedback are a universal concept in all sort of systems)

In absence of direct access to the body of knowledge of folks who engineered the car / complex CAD tools, the best we can do most of the time is literally FAFO. But then, what works for one person might not work for another (or might not even work for the former person, and its just that they haven't found out yet. Some times one finds out but then there's a question of how much did that mod contribute to the failure? I'm sure many many people used Eibach springs without flipping their cars). I think Dialcaliper's thread was the least FAFO mod discussion I've seen on this forum (and I will note that the conclusion there was not to deviate that much from stock formula).

WRT to ride height used in some series, it was picked because maybe it makes sense for that series, but there's probably a bunch of other modifications that go along with the ride height? To me, it would make sense to start individual threads about specific Fiesta "formulas" and maybe try to analyze them in depth rather than trying to list all of the "good mods" from everywhere (like even if we scope it down to racing, a "good mod" can mean different things for road racing or rally or even a specific form of road racing)

 

[SteveS]

They run spec suspension in the ST240 series: AST 5300 - Championship control suspension - Full Kit RAC-F4001S, which uses adjustable coilovers. No aftermarket sway bars. They also run a spacer kit. Suspension Spacer Plate kit 74TM-SP-301

The junior series runs poly bushings.

 

[Snrub]

The junior series kind of has a minimum ride height, but it's pretty low.

"Minimum Ride height. The car with driver aboard must at all times be able to pass over a 95 mm high x 600 mm wide block / angled plate situated on the car centre line without touching it."

That's about 3.75", while my car is currently sitting at 6" (OEM original) by that metric. I measured floor to ground, ignoring the resonator.

What spring rates do they typically run?

For me, it's because the definition of "good" varies depending on what you want to achieve.

Paraphrasing a former president, it also depends on what the definition of "is" is. I strongly suspect it's possible to come up with some general guidance, rules of thumb for common scenarios.

 

[Dialcaliper]

The junior series kind of has a minimum ride height, but it's pretty low.

"Minimum Ride height. The car with driver aboard must at all times be able to pass over a 95 mm high x 600 mm wide block / angled plate situated on the car centre line without touching it."

That's about 3.75", while my car is currently sitting at 6" (OEM original) by that metric. I measured floor to ground, ignoring the resonator.

What spring rates do they typically run?



Paraphrasing a former president, it also depends on what the definition of "is" is. I strongly suspect it's possible to come up with some general guidance, rules of thumb for common scenarios.

Depending on whether they allow front lower subframe braces, that might not be as low as you think.

With stock suspension and a Pierce lower brace, I measured 4.75” clearance to the subframe brace. With the Mountune springs that came on the car which were advertised as a “mild” lowering of about 0.8” in front, subframe brace was right around 4” off the ground, and I definitely skidded off a few rocks and did a grind on the asphalt edge of a dirt turnout trying to get back on the road

 

[Snrub]

Depending on whether they allow front lower subframe braces, that might not be as low as you think.

With stock suspension and a Pierce lower brace, I measured 4.75” clearance to the subframe brace. With the Mountune springs that came on the car which were advertised as a “mild” lowering of about 0.8” in front, subframe brace was right around 4” off the ground, and I definitely skidded off a few rocks and did a grind on the asphalt edge of a dirt turnout trying to get back on the road

I think I quoted the wrong thing. Here's what I think is correct.

Mk7 Zetec S: Minimum ground clearance is 110mm (4.3") with driver (with full racing kit) aboard, which will be measured from the lowest point of the front subframe (rear) retaining bolt as shown in Image 1. This bolt must remain as standard OEM and must retain the original 5mm washer, as shown in Images 2 and 3. Measurement will be taken from either side of the car. Edit: I measured my car on OEM suspension and it's at 5.0" to this bolt.

Your suspension knowledge is likely among the top 3 people on this forum. What's your take on how to increase the performance of the FiST's suspension while also decreasing rollover risk?

 

[WannabeST]

^ That amounts to saying trying is the first step towards failure. It's common when building a racer car to consider things that make the car safer, so why not consider it as part of this discussion?

The first and second sentence in my response were safety related.

Also failure is a good thing. We learn from failure. Failure is almost inevitable if you want to be good at anything.

My comment was intended to be that people should consider the overall risk of their activity they choose to do. I am always 100% in favor of adding safety to a car. However, even in professional racing, you will see that even in teams with almost unlimited budgets, people still get hurt.
Many people do not own motorcycles simply because of the risk of injury. No matter how much safety you add to a motorcycle, it is inherently dangerous. Regardless of how economical and fun the riding experience is, the danger is always present. Same can be said for motorsports. Driving a car will pretty much always be more safe than a motorcycle.
However, one should always assess if this risk lines up with what they consider to be "worth it". Like in the example of a fiesta, one should ask them self: "Am I ok with the potential roll over risk of this chassis?" if no then ask "Am I ok with investing time and money to mitigate the risk of roll over in this chassis to then continue in motorsports activities?" If no then: " Am I ok with the risk of motorsports even if I was in a safer chassis? If no then motorsports isn't for that individual, and there is nothing wrong with that. When you get to my point where you instruct at 30+ events in a year and get dozens on dozens of students, you will realize that motorsports is not for everyone.
It's much safer over all, for someone to realize that motorsports is not for them vs someone invest money and time and energy into an activity that they later realize they are not even ok with the risk on.
You can translate this in to almost any activity with any level of risk too.