mymomswagon wrote:Okay, first of all, I need to improve the driver. Absolutely need more seat time, more practice with these mysterious "slaloms" and find a way to suck less and still have as much fun as I'm having. The cheapest, easiest thing to do would be to relax and participate in FAST and other events...
Your head is in the right place.
But I'm kinda OCD, so I think about future upgrades and improvements. For some, "planning the vacation" is half the fun and I'm one of those people. And, it's a quiet day here in semi-retired consultant world, so why not type? Comments are welcome, of course
The sage advice is to always try to do one upgrade at a time and give yourself time to learn exactly what it did. If it's adjustable, adjust it and see what the settings do. Learn that ONE part and what it did for you.
I don't think this car will win any class as long as Miatas are allowed to compete
so I'm kinda on the fence about targeting a class. That said, my thinking is I'm S5, or S3 or Fun Run, at least for a couple years. Down the road, an ECU tune may push me into an M class.
I'd stick with S5. You don't have the power to compete in S3, and you're not willing to do the level of suspension mods you'd need to compete in M4.
So far, I've made two purchases:
1. upgraded the stock 19mm rear sway to a 22mm GTI rear sway. Car feels better and rolls less. NVH is just slightly more. Wife doesn't doesn't notice
2. bought a spare set of wheels and tires (same tires as came with the car) for autox use. Training wheels/tires that will save the edges of my DD tires. They were cheap off of craigslist.
Give yourself some time to learn that swaybar. Then play with the alignment. Have you done alignment yet?
To stay in S classes, I'm thinking three upgrades: better tires, adjustable dampers, and adjustable rear sway bar. For the most part, all three could be put on the car or adjusted Friday night and taken off Sunday in less than an hour and a half each way.
Modding/unmodding a car between events is kinda silly. Hard on you. Hard on the parts. Plus, then you're driving a significantly DIFFERENT car than the one you drive daily. Ideally, you'll find it easier to learn if the car is exactly the same when you drive it daily.
Tires: Once I get some more seat time on my Training wheels, I plan to replace tires with a more aggressive compound, either Ultra high performance or Max performance, in Tire Rack terminology. Diameter will have to be smaller in order to use my 15" wheels but I'm okay with that unless I run into some 16" wheel bargain on craigslist that would expand my diameter choices. Thinking 195/55 BFG sport comp2 for UHP or Star Specs for Max performance.
Last I checked, 17" was the place to be for cheaper tires. Not sure if that applies to 195's, though. You might do better to stick with 15's or 16's there.
Ooooh:
195/55-16 RE-71
Or, these are dirt cheap, and surely a significant step up from your OE All Seasons:
195/55-16 Firehawk
16" gets you back to the height that's appropriate for your car. Shorter tire will give you better gearing for acceleration, but shorter legs. Your top speed in 2nd gear (usually very important for autocross) will be less with a shorter tire.
Wheels: Your car should have 5x112 43mm offset wheels. The GTI 16's are 49 and 51mm offset because they're fitting wider tires and need the inside clearance. You don't need that since you're sticking with a 195. So, Ideally, you'd stick with a 49 offset... or possibly less (check your fender clearance... you could probably go down to a 40 or even 38 without issue). That gets you the track increase WITHOUT having to fit spacers and/or longer wheel studs.
Plenty of factory options if you look around:
Hmmmm... 16x6.5 40mm offset
Or.. 16x7 42mm offset. (ad says 45mm offset, but look at the photos)
Dampers. Adjustable dampers make sense to me given my DD ride quality goals. Unfortunately there are no obvious choices for this platform in terms of rear shocks that adjust on the car, unless I go full coilover kit, which I won't do. If I don't find an off the shelf solution, it leaves me with deciding if I want to remove adjustable shocks for adjustment, or just switch them to a firmer non-adjustable for events, or just get something that's a moderate compromise and leave them on.
Lots to think about here. In my experience, staying "stock", you can often get away with stock front dampers on a FWD car. Where the adjustability really comes in handy is the rear. Having the rear as stiff as you want it for an autocross is downright uncomfortable on the street. So, even if you leave the front alone (or just get a good non-adjustable front strut when you need it), having something easily adjustable in the rear would be a Good Thing.
I'd first look and see just how close your rear shocks are to what's on a regular Golf or GTI. They might not be EXACTLY the same, but maybe they'll fit? Maybe some very slight modification will make them fit? That might be your easiest route to adjustability. If not, Rear shocks on a FWD car are usually pretty basic. You could adapt something to work and get the adjustability that you want. Photos of your rear suspension would help here. Unless there's an easy bolt-on option.
Sway bar. I think the car can handle a stiffer bar but my lack of driving experience may be fooling me. If it can, after firming up dampers, I'd look a bar with a modest bump in firmness to what I have, with the ability to adjust it even firmer.
You can surely do more rear bar. Either an adjustable aftermarket GTI bar, or mod the one you have. (BTW, the fact that you share a rear bar with a GTI probably means that the whole rear subframe and suspension is the same... factory rear GTI shocks might be a good upgrade for the rear of your car. Not adjustable, but firmer, and surely plenty streetable.) Mods you could do: If there's enough space at the attachment point of the arm, drill another hole as far inboard as possible, shortening the lever arm of the bar, thus making it stiffer. Or... if there's a nice straight section in the middle of the bar, you could get a hollow tube (1/8" wall or so) with a ~22mm inner diameter. Cut a couple feet out of your bar, replace it with the larger diameter tube. You could save a couple pounds AND have a stiffer bar! If you don't mind doing your homework and math, you can have a reasonable idea of how much stiffness you're adding (and make the arms adjustable, anyway... you could LENGTHEN the arms to give you a softer adjustment point if needed). And I know a guy (Joe Brannon) would could weld it up for you. For under $100, you could create something equivalent to an aftermarket bar that would cost $2-300 or more.
What I wonder about: given my rear damper concerns wrt adjustment and firmness, can I substitute adding dampening firmness in the rear with more firmness in rear sway bar?
Yup. But, everything affects everything else. There's always a trade-off. You already know it's going to affect NVH. Stiffness of a bar is a function of the diameter to the 4th power... a minimal change in diameter yields a major change in stiffness. Going from 19 to 22mm was a big step. Going from 22-25 would be an even larger step. (but, probably a very good one)
One of the things we learned on the FASTiva was what "too much rear bar" does. Unfortunately, our "rear bar" is non-adjustable, so we left it and modded around it. What happens with too much rear bar is that the inside wheel lift will happen almost instantly. And the other thing I learned is that as soon as you get rear wheel lift, your swaybar is no longer a factor. It has transferred all of the weight that it possibly can, and ALL of your roll resistance is now coming from the front! So, if you've got 900# of roll resistance in the rear, and 200# of roll resistance in the front... as soon as the wheel lifts "a little", all roll resistance shifts to the front, you instantly get "a lot" of wheel lift. It makes the car feel very unsettled.
23-24mm, even up to 26mm rear bars are not uncommon in the FWD aftermarket. You've got a pretty heavy car, and it's a wagon, so lots of rear weight. I wouldn't hesitate to go up to 24mm. And I'd go up to 25-26mm as long as it was adjustable.
You might find that the car needs more front damping to keep that wheel lift "controlled". (front damping, not rear) So, front adjustable struts would be nice. But, you could "set them and forget them". They don't need to be crazy stiff. Just enough to do their job.
I've been down the firmer bushings and adjustable camber plate path on a BMW and though I liked the razor sharp steering feel, I decided it was not for me. Wife also decided it was not for me
There's something to be said for compliance. Both from a comfort AND handling perspective. Colin Chapman is rumored to have said it best: "any suspension will work if you don't let it".
I've thought about just playing around with spacers to widen the front track. Seems like it would reduce understeer and it would be a cheap, easy to undo experiment. Low priority, something to do after the things above are sorted out.
I've never bothered playing that game. At least not intentionally. Remember that moving the offset out changes the load on your hub bearings. Can be a problem on some cars, especially when coupled with high-grip tires and autocross cornering loads. If you do spacers, please fit longer wheel studs! (I've seen a wheel depart a car due to that very thing... they roll a loooooong way)
). You also mentioned bargain 16s, but tire choices there could be similarly, if not more, limited. And you already have the extra 15" wheels. 
).
