STX Rules and Setup Questions

[mpross]

Originally Posted by strat61caster

See Blaine's post above, breaking axles may have been overblown as I haven't seen anyone with one recently. Keep an ear out for axle ticking, buy new axle nuts if you start to hear it tick (fixed my ticking) and keep the e-brake lubed so that noise isn't throwing you off either, they rarely go without warning.

As for 'willing to eat costs', for some it's a AAA tow truck, a $140 replacement axle and a greasy afternoon, for others it's a $500-$1000 trip to the dealership. If you're a casual autocrosser I wouldn't worry about it, if you're planning on 50-100x hard launches a year on 245 RE71R/BFGRS, might be worth sacrificing the looks if you can't prove the performance benefit to yourself.

Ultimately, this is racing, take everything with a grain of salt and prove it to yourself. Do whatever feels right, if I was your buddy I'd shrug and say 'keep it low, if you bust an axle you'll know why'

Maybe it was just a bad batch and they've all been broken now, all the ones left are rock solid. In any case, useful suspension stroke keeps me from lowering the car, not the broken axle potential.

That's reassuring. I'm definitely not slammed and didn't want to lower mine to the point where it was no longer functional from a performance standpoint. It's never rubbed on any corner so far, so suspension travel seems fine. I'll just be conscious of that possibility and if something does happen I would definitely be in the greasy afternoon, less expensive category.

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[Silverspeed]

Originally Posted by strat61caster

See Blaine's post above, breaking axles may have been overblown as I haven't seen anyone with one recently. Keep an ear out for axle ticking, buy new axle nuts if you start to hear it tick (fixed my ticking) and keep the e-brake lubed so that noise isn't throwing you off either, they rarely go without warning.

As for 'willing to eat costs', for some it's a AAA tow truck, a $140 replacement axle and a greasy afternoon, for others it's a $500-$1000 trip to the dealership. If you're a casual autocrosser I wouldn't worry about it, if you're planning on 50-100x hard launches a year on 245 RE71R/BFGRS, might be worth sacrificing the looks if you can't prove the performance benefit to yourself.

Ultimately, this is racing, take everything with a grain of salt and prove it to yourself. Do whatever feels right, if I was your buddy I'd shrug and say 'keep it low, if you bust an axle you'll know why'

Maybe it was just a bad batch and they've all been broken now, all the ones left are rock solid. In any case, useful suspension stroke keeps me from lowering the car, not the broken axle potential.

Well said. IMO this is something that the SCCA should allow to be upgraded from a durability perspective in the ST classes. If I do break one I'd like to be able to upgrade them so it doesn't happen again.

[BlaineWasHere]

Originally Posted by Silverspeed

Well said. IMO this is something that the SCCA should allow to be upgraded from a durability perspective in the ST classes. If I do break one I'd like to be able to upgrade them so it doesn't happen again.

I thought about writing a letter about the axels after I broke one two years ago. But then I didn't break another so I never did.

For me stronger axels isn't something that makes you faster.

[cjd]

Originally Posted by BlaineWasHere

I thought about writing a letter about the axels after I broke one two years ago. But then I didn't break another so I never did.

For me stronger axels isn't something that makes you faster.

It might need a lot more detail... Same or greater weight, for one. Does that just go for axles, or also driveshafts? How about rods and pistons? It's a slippery slope.

[DocWalt]

Unfortunately there's an idea that some cars could suddenly be a lot faster with some reliability mods. Heck, the radiator and oil cooler allowance took quite a while to be accepted. Some cars would lose power after a run or two due to heatsoak and they were depending on that loss in performance to keep classes balanced, which is a touch silly.

[Silver Ignition]

Okay guys...got my 14mm, 17mm, 19mm and 22mm wrenches, tape measure and a Hunter Alignment rack.


Right now my front is VERY low by your numbers at 24.75".


Has anyone input the geometry into a calculator to determine the IDEAL ride height for a proper roll center?


Tonight I plan on setting my front at 25.25" and rear at 25.5". Next autocross is 5/22 so we'll see how she does.


Also while it's on the rack I think maybe I'll take measurements to input into a roll center calculator and try and dial in the PERFECT ride height.


Any comments or concerns?

[GeorgeJFrick]

Originally Posted by Silver Ignition

Okay guys...got my 14mm, 17mm, 19mm and 22mm wrenches, tape measure and a Hunter Alignment rack.


Right now my front is VERY low by your numbers at 24.75".


Has anyone input the geometry into a calculator to determine the IDEAL ride height for a proper roll center?


Tonight I plan on setting my front at 25.25" and rear at 25.5". Next autocross is 5/22 so we'll see how she does.


Also while it's on the rack I think maybe I'll take measurements to input into a roll center calculator and try and dial in the PERFECT ride height.


Any comments or concerns?

My only thought was that corner balance can't be perfect while still having perfectly balanced ride heights all around.

[renfield90]

Originally Posted by Silver Ignition

Okay guys...got my 14mm, 17mm, 19mm and 22mm wrenches, tape measure and a Hunter Alignment rack.


Right now my front is VERY low by your numbers at 24.75".


Has anyone input the geometry into a calculator to determine the IDEAL ride height for a proper roll center?


Tonight I plan on setting my front at 25.25" and rear at 25.5". Next autocross is 5/22 so we'll see how she does.


Also while it's on the rack I think maybe I'll take measurements to input into a roll center calculator and try and dial in the PERFECT ride height.


Any comments or concerns?

This thread will help you out: http://www.ft86club.com/forums/showthread.php?t=26661

Includes front and rear roll centers at OEM height. I haven't dug into the whole thread yet (many pages) but on the first page at least, they don't include how they derived those numbers. But they do come from a Penske engineer so I would consider them valid.

According to him, front roll center drops below the ground with more than 1" drop from OEM. This is gonna make me do some thinking...the STX FRS I drove was absolutely slammed but drove really well anyway IMO.

[slyphen]

asking for a friend. are 2013 STI qualified for STX?

[gtslow]

Originally Posted by slyphen

asking for a friend. are 2013 STI qualified for STX?

WRX STI falls under STU

[DocWalt]

Originally Posted by slyphen

asking for a friend. are 2013 STI qualified for STX?

No, they're in STU (assuming you mean the WRX STI and not the Series Blue)

[strat61caster]

Originally Posted by slyphen

asking for a friend. are 2013 STI qualified for STX?

See the rulebook, specifically Appendix A:

http://www.scca.com/pages/solo-cars-and-rules

[BlaineWasHere]

Originally Posted by cjd

It might need a lot more detail... Same or greater weight, for one. Does that just go for axles, or also driveshafts? How about rods and pistons? It's a slippery slope.

It is a slippery slope. I was going to specify actually only axels.

The thing is it's difficult to police. Would anyone even know if I had upgraded axels right now?

The main reason I bailed is I haven't broken another axel in almost 100k miles and when I thought about it I think it's best to keep the weak link the axel. If I upgrade them I don't wanna go around blowing up diffs.

[Silver Ignition]

So ride height is now at 25.25" front, 25.5" rear ground-to-fender...4.75" front, 5" rear ground-to-pinchweld.


Car feels much looser, a lot more body roll (dampers are set to full soft for the rain aX on sunday) so I'm thinking it's time to bump up rebound and let the dampers do their job.


Even with the extra body roll I was able to maintain much higher speeds on the twisty road I take to and from work...one corner that I usually take between 52-54mph I took at 74mph! Not sure if placebo or if maybe it just instills more confidence but I cant wait till the 22nd for the next local aX!