Discussion in 'Fiesta ST Autocross' started by AlanBDahl, Oct 21, 2013.
So do you already have a rear bar? Which one do you have? Can you tell how it affected the handling?
I have no rear bar. I found the car prone to oversteer not understeer, but that was just one time. So who knows.
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Well look for a base Fiesta front bar, its only a little stiffer than the ST piece.
The alternatives are all too big.
If you lift off it rotates pretty nicely. My concern with more front bar is you may create quite a push and kill that rotation. A base fiesta bar would be cheap to try and mild difference at least. I want a more solid rear personally.
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If I stay on the stock wheels I would go to a 205 45 dunlop...If I go to a 16 then the offset of the aftermarket wheels would mean I could not widen the front track
Rebound yes, compression no... More rebound will cause the rear to jack down and cause the opposite front corner to unload. In "theory" and in most cases practice, compression resists roll and actually preloads the opposite front corner driving the tire into the ground and "limiting" wheelspin.
All the other things you mentioned are all pluses. You Street class guys need to figure out whether a smaller front bar or adding a rear bar is what works to reduce that roll.
I was a little slow on the reply, I was commenting on adding a large front sway bar, not shocks.
I've never had the chance to tune a car with adjustable shocks or do before and after tests with differently valved shocks.
Since that's not a knob I could adjust I haven't thought about it much.
I have put a big anti-sway bar on an old mustang convertible but it was a mess before and after the change. It traded body roll for chassis twist but at least it felt less boat like.
Luckily modern unit bodies with a roof are stiff enough that suspension adjustments generally do what you think it should.
So I got back from the first autocross with the FiST and I must say I'm impressed.
For one, I learned about how to manage oversteer and getting the car to rotate. Rotation was exceptionally easy (with the help of lift off oversteer) and understeer only really occurred when I took completely the wrong line/carried too much speed.
With the Rivals, I ended up going with 42/38 cold which seemed to work pretty well. I certainly wasn't 'fast' at least not up to what the FiST can do, but since the results aren't posted yet I can't see quite yet how I did.
Edit- A couple things I should probably add.
For one, I didn't really notice my tires rubbing, but that was mainly because of sensory overload with the new car and instructors yelling instructions while driving.
The other thing was brake fade. I drove the car for two runs nearly back to back, and then a friend hopped in and drove it for a third consecutive with maybe 15 minutes spanning the runs and you could very clearly smell the brakes as we came in. I hadn't noticed this issue all day until putting a bunch of runs on it consecutively.
More data, FWIW: Ran through Solo Novice School last Saturday and first event last Sunday, using 42F/35R Saturday (sunny, dry, windy, temps in 60s), and same on Sunday (cloudy/damp>>wet/rainy, temps about 60), and am pleased with results. Smokin was at same events, as instructor on Saturday and butt-kicker on Sunday, and I believe ran same pressures with good results, though I'd like for him to offer his own thoughts.
Did you have the traction control completely turned off? if not or if you were in Sport mode, that's why your brakes were hot. See my Ax thread...
You improved on each run grasshopper. That is what we aim for....
I had it completely off. I would assume the closeness of the runs did the brakes in. I know people that track their FiST were having some issues with brake fade.
Fade or just smell? Smell I get just from driving it hard, I have yet to have any fade issues.
Just smell. After I smelled them, I let them sit for a while to avoid the possibility of fade.
I think that the e-diff is braking through the corners and heating up the brakes. I can feel the heat radiating out after a couple of runs. I never got any fade, but I was surprised when I sprayed my tires, and the wheels started sizzling when they got splashed with overspray.
My FiST is bone stock (except for drop in intake filter), thus was using the Bridgestone RE050 tires... On my best run I has 40 lbs. or air in the front, and 38 in the back. I had some mild under steer and the rear did seem to move pretty well. I was 1st in class, 19th in PAX, but I can tell more is in the car...
My question (using the stock tires):
1.) What tire pressures are you using?
2.) Which traction control setting are you selecting?
3.) What (if any) modifications can we install and stay within G-Stock class?
1) 42 / 36
3) there's a rule book at http://www.scca.com/solo/content.cfm?cid=44517
here are a few off the top of my head:
drop in air filter only - can't change/cut the box or any routing of the intake (so, no cone or CAI)
you can replace the exhaust from the cat back, but it must exit the car at the original exhaust point
pretty much no other changes to the engine - no tune, no porting, no headers
alignment can only use slop in the stock tolerances and bolt holes... no camber bolts or plates
you can change to firmer shocks that use stock attachment points and don't change the ride height (no coilovers, must use stock springs)
no more than two adjustments per shock.
wheels must be same width (7"), within 7mm (1/4") of stock offset, but you can go +/- 1" on the diameter (16,17, or 18's)
tires must be >140 treadwear this year, >200 treadwear in 2015
you can change your oil. I'm going to change mine this weekend.
Thanks for the input, I am already planning to purchase some 17' Sparco wheels to replace the OEM wheels (to use for eventual winter duty), but I didn't know I could get away with an exhaust too.
I am guessing something to the effect of an FSWerks cat back would not be an issue?
Also, if I gut some of the interior, that wont change which class I stay in? I have the stock seats and got thrown around a ton last autoX so I just got a set of harnesses to bolt in... might as well leave the back seat out for the summer...
You cannot change the interior aside from matching oem configurations.
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I don't think you can remove the back seats (or anything else that's tied down with factory fasteners). You can't change out the front seats unless you get a pair of the optional Recaro seats (basically installing the factory option yourself).
You can add, change, or remove a single anti-sway bar.
I just read you can change your shift knob.
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