Scca STX autocross build

[Cligedy]

Hello, after driving my Fiesta ST in Street class since I bought it in 2013, I'm switching to the STX class. For those who aren't familiar, Street class mainly restricts mods to wheels/ tires, exhaust and shocks. STX allows further mods like intake, header, coilover, plus a few options to reduce weight.

This car is my daily driver so I was hesitant to go down the ST* path, since when I did that with my Miata I wound up with a car that was no much fun on the street.

My goal is to make class legal mods that make the car more fun to drive and make the car competitive in National competition. I hope to have a build that achieves 90% of the competitive potential while keeping 90% of the daily drivability.

 

[awwwww_shift]

Good luck with the build! Going to be a fine balance on these cars to keep streetability, but have that fine chassis control.

Also going to be interesting to see where the rulesets go from here(open boost is not legal in street or ST* currently, but the option is being discussed to make it legal in ST*)

 

[Cligedy]

For my Street build, I used a Cobb drop in, Koni shocks, Sparco wheels and a BFG Rival / Dunlop Z2 combo.

When I started my build, the aftermarket was minimal for the FiST, so I built my own housings for Koni Race double adjustable strut inserts up front. RaamAudio was extremely generous and donated his oem struts from his build so that I was able to keep my oem struts as needed. The Koni race struts are probably overkill, but they are very nice. When Koni released their yellow Sport shocks, those went on the rear. Because of Street class rules, the stock springs and ride height had to remain unchanged.

I was hoping that the Rival's added diameter would give me a few extra mph at the top of second gear, but was worried about fitment. I was right about both, the tires rubbed like crazy, but the car was faster with them than the Dunlops. The Rival's also felt terrible to drive, so when the Dunlop Star Specs came out, I switched to them all around.

Next go-around, I will be trying the newer Rival- S, as it sounds like they have greatly improved the feedback.

 

[Cligedy]

Good luck with the build! Going to be a fine balance on these cars to keep streetability, but have that fine chassis control.

Also going to be interesting to see where the rulesets go from here(open boost is not legal in street or ST* currently, but the option is being discussed to make it legal in ST*)

As much of a pain as not touching the boost is when tuning, I think that leaving the rules as is gives the FiST a competitive advantage. ECU tuning to raise the redline can get the car back above 60mph in second, and remove the 2nd gear torque reduction.

Torque is cut in 1st & 2nd gear by about 30lb/ft (don't hold me to that #) but ECU tuning could restore that and still be compliant to the rules. That is a meaningful amount of power to be unlocked, but is a chore to do it, as any OTS tune will almost certainly tinker with boost levels. I don't think any other STX car (maybe FoST) can get that kind of bump with tuning.

If the SCCA opens up boost then the FoST, WRX and the Gti have big gains available. If the proposed rules go through, the FiST will not be competitive unless cars/ classes get shuffled around.

 

[M-Sport fan]

For my Street build, I used a Cobb drop in, Koni shocks, Sparco wheels and a BFG Rival / Dunlop Z2 combo.

When I started my build, the aftermarket was minimal for the FiST, so I built my own housings for Koni Race double adjustable strut inserts up front. RaamAudio was extremely generous and donated his oem struts from his build so that I was able to keep my oem struts as needed. The Koni race struts are probably overkill, but they are very nice. When Koni released their yellow Sport shocks, those went on the rear. Because of Street class rules, the stock springs and ride height had to remain unchanged.

I was hoping that the Rival's added diameter would give me a few extra mph at the top of second gear, but was worried about fitment. I was right about both, the tires rubbed like crazy, but the car was faster with them than the Dunlops. The Rival's also felt terrible to drive, so when the Dunlop Star Specs came out, I switched to them all around.

Next go-around, I will be trying the newer Rival- S, as it sounds like they have greatly improved the feedback.

Which size Rivals were you using that they rubbed?

Also; when you say "Koni RACE" inserts, do you mean their regular rebound and compression adjustable yellow Sport deals available for other cars, or were these their alloy, threaded body, full race damper inserts?

 

[Cligedy]

Which size Rivals were you using that they rubbed?

225/50R16. They aren't offered in that size anymore, the Re71R is though.

I will be trying the 215/45R16 Rival S this season, unless I am able to sell my wheels. I'd like to move to 15" when my Sparcos sell.

 

[Cligedy]

Which size Rivals were you using that they rubbed?

Also; when you say "Koni RACE" inserts, do you mean their regular rebound and compression adjustable yellow Sport deals available for other cars, or were these their alloy, threaded body, full race damper inserts?

No, not Koni Yellows. These are their race inserts. They aren't threaded, but you can build the housing to be. I didn't (because street class) but I probably will build a new set that are.

http://www.koniracing.com/8611.cfm

 

[M-Sport fan]

No, not Koni Yellows. These are their race inserts. They aren't threaded, but you can build the housing to be. I didn't (because street class) but I probably will build a new set that are.

http://www.koniracing.com/8611.cfm

THANKS!!

Just how much work was involved to get these into the factory FiST front strut 'shells'?
Is it a 'press fit', or is there definite welding involved?

Would it be any easier to just convert these to a coil over with a sleeve (like a Ground Control kit, or such) IF one does not have to worry about class rules?

Just how far out of balance would these be when used with the standard, made for the FiST, 'off the shelf' Koni Sport yellow REAR shocks due to (radically) different valving (range of adjustable rebound valving, WAY out of the front's range FIXED compression valving), or are they fully compatible, depending on what spring rates used?

 

[Cligedy]

I have some good pictures, but it's a chore to get them posted here.

The strut housing must be welded, as it is a threaded nut that holds the damper in place. Like I mentioned, I will eventually build a new set with a threaded sleeve so that I can use standard 2.5" springs and select an ideal spring rate.

The main challenge to building this for the threaded sleeve (because I start with an oem strut) will be getting the spring seat off of the housing. I don't know if I can press it off somehow or if I have to cut it off.

Regarding the mismatched shocks, I discussed this with Lee Grimes at Koni. The Race shocks are adjustable for rebound and compression and have a wide range of spring rate compatibility and the yellow sports will be fine for the spring rates I will probably run. I f I decided to go to 300+lb/in rear spring rates then I would need to get more aggressive shocks.

 

[awwwww_shift]

I have some good pictures, but it's a chore to get them posted here.

The strut housing must be welded, as it is a threaded nut that holds the damper in place. Like I mentioned, I will eventually build a new set with a threaded sleeve so that I can use standard 2.5" springs and select an ideal spring rate.

The main challenge to building this for the threaded sleeve (because I start with an oem strut) will be getting the spring seat off of the housing. I don't know if I can press it off somehow or if I have to cut it off.

Regarding the mismatched shocks, I discussed this with Lee Grimes at Koni. The Race shocks are adjustable for rebound and compression and have a wide range of spring rate compatibility and the yellow sports will be fine for the spring rates I will probably run. I f I decided to go to 300+lb/in rear spring rates then I would need to get more aggressive shocks.

Lee is good s#!t. He's helped me out in the past on some neon projects. 10/10 would recommend. Also, for revalves on the other coast, ProParts is in the same league of knowledge and proficiency. And Jeff there is a fellow STS/STC/ST competitor who can walk you through a lot of the good/bad advice people seem to toss out online.

Best of luck with the build, and LMK if you feel like selling that original setup...

 

[M-Sport fan]

I have some good pictures, but it's a chore to get them posted here.

The strut housing must be welded, as it is a threaded nut that holds the damper in place. Like I mentioned, I will eventually build a new set with a threaded sleeve so that I can use standard 2.5" springs and select an ideal spring rate.

The main challenge to building this for the threaded sleeve (because I start with an oem strut) will be getting the spring seat off of the housing. I don't know if I can press it off somehow or if I have to cut it off.

Regarding the mismatched shocks, I discussed this with Lee Grimes at Koni. The Race shocks are adjustable for rebound and compression and have a wide range of spring rate compatibility and the yellow sports will be fine for the spring rates I will probably run. I f I decided to go to 300+lb/in rear spring rates then I would need to get more aggressive shocks.

Again, THANKS!!

I would probably forego the factory lower perch/mount, and get the complete GC conversion setup if/when it is ever released to use these inserts.

I was not too sure that ol' Lee was still there, since he had also helped me many times in the (far) past when I used the Sport double adjustables on my Z28.

Supposedly, Truechoice in Ohio is also adept at rebuilding/re-valving Koni products as well, although I've never used them myself.

 

[Kazz]

I, too, have modified cars to the point that they're no fun on roads (coilovers and truly nasty streets). So I'm interested in your impressions of the first suspension mods you made and the upcoming coilover conversion for everyday driving. Also, I'm curious about how competitive the FiST is in STX. I understand it's quite competitive in the Street classes. And I'll be autocrossing mine for the first time this Spring.

Good luck with the upgrades and at events!

 

[Cligedy]

The shocks were a sound addition. They made the car better on the streets, the car was much calmer especially over surface irregularities like expansion joints on the highway. On the autocross course, I won't claim that the shocks were worth much time, but the car is easier to drive and so I was more consistent and more comfortable at the limit.

I have serious doubts that the FiST is competitive at the pointy end. When researching whether this was a good idea, someone made the point that if a car like the FiST was competitive, then somebody would have done it with a Cooper S.

Like I said earlier, I think that the ECU rules as they stand favor the FiST. If the proposed rule change is passed then one big advantage will evaporate. I have not written the SCCA in support or opposed to the rule. If the rule passes, then I bet that a lot more drivers show up for the class, which is good for the sport.

 

[awwwww_shift]

The shocks were a sound addition. They made the car better on the streets, the car was much calmer especially over surface irregularities like expansion joints on the highway. On the autocross course, I won't claim that the shocks were worth much time, but the car is easier to drive and so I was more consistent and more comfortable at the limit.

I have serious doubts that the FiST is competitive at the pointy end. When researching whether this was a good idea, someone made the point that if a car like the FiST was competitive, then somebody would have done it with a Cooper S.

Like I said earlier, I think that the ECU rules as they stand favor the FiST. If the proposed rule change is passed then one big advantage will evaporate. I have not written the SCCA in support or opposed to the rule. If the rule passes, then I bet that a lot more drivers show up for the class, which is good for the sport.

Ummmmm, the STX class champion last year was a Mini S.... Craig Wilcox....

 

[Cligedy]

Ummmmm, the STX class champion last year was a Mini S.... Craig Wilcox....

Yup, he sure did. He's also the reason the ECU rules will probably be changed. Which is not to say he did anything inappropriate.

 

[awwwww_shift]

Ah, wasn't sure if that's what you were referencing or not. I agree something needs to change with the ECU rules, but not 100% sure if it means open ecus or not.
Either way, between the STX finish, and STS protests, a lot of things were brought to light after nats last year. (I was partially involved in the STS drama... not first hand, but the car I was running)

 

[M-Sport fan]

I have serious doubts that the FiST is competitive at the pointy end. When researching whether this was a good idea, someone made the point that if a car like the FiST was competitive, then somebody would have done it with a Cooper S.

When you say "pointy end" do you mean classes ABOVE H/Stock prep level/rules?

 

[Cligedy]

When I say pointy end I mean those are able to contend for national championships.

 

[M-Sport fan]

When I say pointy end I mean those are able to contend for national championships.

I thought that there were a few of our cars on, or at least near the podium in H/Stock in the recent past nationally.

 

[Cligedy]

You are right. Our car could absolutely win HS, I meant winning in STX may be a long shot.