On ovals like Talledega its an aero advantage to have the side body panels bulge on the inside (driver side) and flat on the outside within the tolerances allowed so there is a sideways wing. That produces 'lift' on the bulge side thus pushing the car inward counteracting centripetal force
Just how that bulge is accomplished is one of the closely held secrets for NASCAR body techs. At 200 mph even a tiny biy helps enormously.What? you think NASCAR isn't as tech driven as F1?
cheers.

 

Our tires seem to equalize around 47psi f/ 38r. Haven't tried disconnecting the fsb. Car turns in quite well off throttle if your set up is on time, meaning not late and the cause of this is not looking down the track far enough. You need to start turn in much sooner than you think. Biggest problem is not waiting long enough to accelerate out of turns which pushes the car wide. A blip of the throttle will usually get things back in line. And my car like a fairly wide open course. Tight tracks are no good with 100hp.

 

How to make an ice cube fast

 

Don't have any idea what equalizing tires means but turning the wheels early and having to wait to apply power is a perfect description of understeer. And of course thats the slow route
My fit and others at VIR reduced lap times by 6 to 8 seconds just by removing the FWB. Some things ain't rocket science.
And with Fit power if you get anything to happen when you blip the throttle you are peforming miracles. In any form of racing you need to get the turning done early so your exit is a straight as possible for maximum acceleratuion. The more you try to accelerate in a curve the slower you will go.
cheers.

 

By "equalizing" I think he means that's what his tires settle at after cycles.

Agreed with mkane on the tight course bit... the Fit likes tight courses but when you start getting into keyholes and super tight stuff it's no good because of the almost useless first gear.

I settle the car with breath+throttle all the time if I come in too hot, i'm no miracle worker. If you can't settle the car with throttle you're in the wrong gear.

 

I run SCCA Solo (AutoX) on a national level for both Tours and Pro Solo's


I have run 225 RS3's, 195/50 Toyo R1R's, and 205 Rivals.

Currently, I MUST disconnect my front sway bar to race. After calculating ideal spring rates based on roll rate and corner weights, the front of the car (EVEN with -3.5° degrees of static camber) is so stiff that at full attack with the bar attached it lifts the inside wheel high enough to unload the diff and cause wheelspin. See at roughly :20 with both drivers:
SFR SCCA Rd3 Marina Tyler Vs Neil: http://youtu.be/8YTNU-bQ4SA

I have also helped develope and compete against 2 well sorted GE's. Here's one on on the RedShift Koni/GC setup with the front bar connected, exiting a sweeper and still showing negative camber on the inside (-3.0° camber static, dampers set to soft)
[IMG]http://i824.photobucket.com/albums/zz162/TPColgett/IMG_404300464000983_zps54d090a3.jpg[/IMG ]

If you want to know anything, I'm happy to share

 

^^^ What size tires did you end up liking the best? Were 225 too heavy? 205 too small?...

What coil over are you running?

 

Hnnnnng









Not to derail or anything, I run 2 sets of Direzza ZII on 16x7.5 and a 16x7 both 205/50/16 and love them. I may go up to 225/45/16 for the 7.5" wide in the future, perhaps the ZII Star Spec. I have driven on BFG Rivals and Toyo R1R on different occasions in different sizes as well, and found that I like the ZII more. Why you asked I got the ZII, because it was or probably still is the only Extreme Summer Tire offered in 205/50/16. And it's a hell of a tire in the dry and wet; it may not work for everyone, but it works for me. And all the mumbo jumbo that people have said in previous posts are factual and intelligent; I'm not very technical - I'm just a very good driver.

I PAXed 2nd overall in the wet SFR SCCA 2014 Round1 Results and 5th in the most recent event SFR SCCA 2014 Round5 Results.

 

Size wasn't so much the issue. Tire compound idiosyncrasies matter and so do wheel width. I enjoyed the 225 RS3's but only could keep them warm enough to be "equalized" and happy with a second driver. 195 Toyos LOVED being slightly stretched on my 7.5" wheels, and were excellent if kept cool, which meant a sprayer. Also as 140tw they are being sunset'ed out by 2015. So far the 205 Rival is damn near as wide as the 225 RS3's when mounted and is performing great now that we have sorted pressures and spring/damper/bar settings. Although there is now a new conpound for the RS3 (V2 supposedly does cold/damp better) available in a 195/50R15 that I have my eye on!

I have Skunk2 Pro C's with Swift springs and Koni yellows in the rear.

 

settle after cycles?
breath + throttle?
settle with throttle?

I suggest you take advantage of one of the driver's schools offered in your area. Don't know where Haystack Hills is located but I know there are good schools offered by SCCA, NASA, and Hooked on Driving I think all over CA. I still consider the CA a/xing the most competitive and numerous of all the locations I fcompeted around the US. possibly the state with the most SOLO champions. I think you are referring to weight transfer, both lateral and axial but you need some better descriptions. Self teaching is always necessary but some pointers are vital. Take one with brian redmond and you get real eye openers.
cheers.

 

Interesting, Last event my personal fastest time was also in the wet. I wonder if this is a coincidence or a characteristic of the Fit.

 

Hey man, just because you don't know that street lingo doesn't mean nobody does. You are an engineer. I get it. You require technical speak.

Settle = car is off balance because of understeer or oversteer. Corrected with throttle application and steering input.

Breath = Let off throttle then add throttle, like breath in, breath out. In my situation I let off throttle to transfer weight forward to end the understeer event and then add throttle to compensate for the resulting oversteer and power out.

I know how to drive. I know technical jargon but don't feel the need to throw it out there all the time. I am not an engineer. I drive. If I want instructors i'll ask my friends that are in NASA, but i've had plenty of instruction in my life. Thanks for the suggestions though.

Cheers.


PS

OP listen to TPColgett and DoYouFit? I can personally verify both of them are fast as hell

 

Thanks for the pressure suggestions! I will start there on the new tires.

I was thinking about testing them by putting them on and keeping them on for a day about 12 mile round trip to work and back. Is this a good idea or necessary?
I feel like getting to know the tires a bit before I autocross with them is a good idea.

The one issue with disconnecting the front sway bar is the fact that its the one part of the car that is rusted lol. Although if its working the internals cannot be rusted just the threads. Would some wd40 be suitable to aide in the unbolting of the linkage lol. I assume you are suggesting removing the entire link that connects the sway bar to the strut tower.

I still have 1 1/2 weeks to figure it out

As far as the offset goes I understand what you mean about too little offset being an issue. I mocked up the tires width by wrapping the stock tires with paper and in a full lock turn it with the suspension depressed it sure looks like it would darn near hit. Thankfully you don't turn the wheel that far normally at road speeds. There is only like an inch of clearance. I figure the extra half inch of tire radius would help a bit as well as with the gearing.

What offset wheels do you use DoYouFit? to squeeze 225s on there?

As far as rules the BMW club is pretty relaxed with the inspections and only designates PAX class by using street tires or r-comps in each class of vehicle I am simply H-street as I am using street legal tires. At the moment I just plan to stick with BMW club as my only autocross group. Over time I may get more involved with other groups but the goal is to ease myself in and not get over busy about driving in events lol. I do plan on doing double sessions morning and afternoon at least to make the most of each day .

 

It's a good idea to get a feel of the tire, so there's no harm in that; get to know the tire nice and easy. That way you know what to expect from the tire before driving hard on them. Of course you won't know what it's like at the limit until you get there, but at least you have some expectation of its characteristics.

I daily and autox the same set of ZII so I'm "in touch" with the tire and the car. My pressures are 35 front 37 rear and change according to weather conditions. I don't play with pressures much; I always start low and let the pressures rise by themselves through runs. Everyone's different on how they handle their pressures. I don't unhook my FSB cuz I don't want to, and will never know if it'll benefit me or not. I just drive and adjust to the car accordingly.

The offsets on my two sets are 16x7.5 +42 and 16x7 +41. I had a set of 16x7 +35 as well... It's the width of the rim and not the offset that allows you to mount wider tires, but I may put 225s on the 7.5" wide whenever I'm done with my current set. You can squeeze 225s on a 7" wide; it'll be a bit of a pinch. I like and want it squared or just a tad stretched.

 

You are correct; as an engineer accuracy is important and all I wanted was a real definition of the street jargon. I spend a lot of time with students just getting them to accurately understand what happens when driving a vehicle. In most cases street jargon is incorrect as we'll see later. Jargon isn't cool.
Still don't get what settling mens. Prerhaps the jargon intends to mean transferring weight to increase or decrease understeer but I don't get the application. In a Fit all you can do is minimize understeer or increase it in a corner and by no means is the chassis happy. Or it could mean when you have attacked a corner successfully there are no stresses in the steering as you exit which is correct. One of the most important things students learn is the ability to exit a corner with the steering wheel neutral in the driver's hands. If its not there's improvement to be had.

But letting off throttle to end udersteer is incorrect. Transferring weight to the front will increase understeer; applying throttle to shift weight rearward will decrease understeer in a Fit. And of course disconnecting that sway bar is a big help to start.
And have you mastered squeezing power on or squeezibg and releasing braking the same and avoid stomping the throttle or brakes? Yes, its quick but smooth that works. Have you learned how to straighrten out the corner exit with planing and execution to maximize exit acceleration? have you learned slow in fast out?
When I stated racing 60 years ago I thought I was really good, faster than all my buddies. Then I got in with some NASCAR guys and learned just how slow I was. Fortunately they shared the right techniques with me and I got pretty good. Won lot of autocrosses, champoinships on both coasts, went racing and actually showed a profit that had ti be accounted to IRS. No wins, several shows and provided points that had Honda win many championships. And have taught over 150 students in 15 years, some who went on to race at Indy and win IMSA championships. No one is a self taught first class driver. At least get one of the good books on driving and then self teaching can prosper.
And forget jargon. Be accurate. Jargon is a cover up; if you can't accurately describe whats happening, using jargon is a coverup.
Its weight transfer, not settlling. Its understeer, or push if you like jargon, or oversteer, or loose if everybody knows what you're saying. If not, its nothing. You have no idea how many times we've hasd to correct students just on what oversteer and understeer is and what can be done to minimize their results. Just as your definition of correcting understeer by shifting weight to the front wheels of a FWD vehicle.

 

With the front sway bar disconnected and stock springs does the car lean much more you find? Just curious if anything in a couple days I will see what its like for myself.

 

Yes to your advantage because the lean contributes to more camber and better tire contact. additionally, it removes the purpose of an antisway bar: to lift the inside tire which reduces traction.In fact at maximum limits the inside tire completely lifts and the entire resistance to sliding is left to just the outside tire in a turn. Thats why antisway bars are used to address handling issues not cornering power. In our lawyer rich environment it was apparently decided that manufacturers should try to ensure cars leave the road head first (ie understeer) so the air bags do the most good. Massive front sway bars result. Corvettes and Porsches aside, thats why most cars are deigned for heavy understeer. safest for the normally less skilled drivers whose cars are merekly appliances.

While I'm at it let me address that instructor advice. My guys told me to. Drivers have the reaction time, reflexes, and visual, hand, and butt sensories that can make good drivers. When drivers say they are good drivers that generally what they mean and pretty much they are right.
That much isn't the function of instructors. Its the 'programming' of reaction times where the sensories (eyes, hands, feet, and butts. yes seat of the pants is absolutely vital; (thats why your belts must be properly tight. OEM belts need help.) those inputs are computed into reactions to hands and feet to accomplish what is needed to be done to minimize time used. The 'programmng' of the correct line, the attitude of the vehicle, and manipulation sequences of the pedals, shifter, steering wheel that iis the function of instruction, not teaching you how to 'handle' a car.
It might interest you to know that solo and showroom stock pilots generally show reaction times of about a tenth of a second, far superior to average drivers of about a quarter second or worse with the elderly getting half to one second reaction times. NASCAR pilots get down to hundredths of a second and F1 pilots down to milliseconds That explains why all of us aren't Hamiltons or Vettels.
I teach driving skills updating to the elderly and one of the significant parts of that is showing them just how much their reaction times deteriorate. It goes like this:
Hold a pencil horizontally in your hand stright out from the shoulder. Have someone say "drop" without telegraphing the shout and see how long it takes for the pencil to drop. Some elderly never drop the pencil and nearly all the rest will take at least a second. And when we come to measuring visual and butt sensories it just falls off the table. There are countermeasures that will assist those lost skills.
Good motorcycle and vehicle racers will drop too quick to measure without electronic devices. Try it yourself.
Its good notice to not being distracted by conversatons, cell phones, music, etc. And you too.
If you can try to get in one of the high performance driving schools in your car; the risk is very low and the worth is huge. Sometimes it even lowers your insurance rates.
cheers.
cheers.

 

Didn't we just have this conversation? lol. This is true for a-arms. With McPherson setup dynamic camber (relative to the ground) is lost as the car rolls. Tuners like Spoon and J's make bigger front sway bars for the front (McPherson) their train of thought is to keep the front of the car "flat" in order to not lose camber from front body roll. Lap times proved them right.

I would love to play around this summer testing front bars for a/xing purposes; removing, stock and Spoons bar. See if the same results hold.

 

Disagree with your first point for sure. Reference friction circle. Letting off adds to lateral, it's when you brake too hard it adds understeer if the tires can't handle that extra input. It's balancing act. I get what you're saying but it's not totally true in practice. How much of whatever you're doing is most important (like you said, smoothness). Sure if you slam on your brakes it throws the tire way out of grip limit, you will understeer off course. Letting off just adds a little bit of lateral grip since the tire is not having to deal with so much forward motion and can transfer that to lateral. Once the car is "SETTLED" i.e. not in extreme understeer or oversteer and is easily handled with steering inputs, go ahead and power out.

Also, taking weight off the rear tires allows the car to rotate more. See pickup trucks with no load in the back on ice for reference

Like I said, not slamming on brakes, just playing on that edge of forward and lateral grip.


Also, like I said, this is not something I SHOULD do, it is something I would do if I came in too hot. It happens.

Yes to all those practices you asked if I knew. In normal circumstance i'm not even really handling the wheel on exit, I just catch it as it returns while on throttle.

Nobody said I was using "jargon" to be cool, I just use it because most people know what I mean without having to be a scientist in conversation.

He forgot already.

I believe if you have stiff springs like the GD and their coilovers have, you can get away with no front bar and it may even help. I DON'T think removing the front bar from a stock Fit will be very beneficial at all. If you have stiff suspension you're limiting travel with that enough, the sway bar just does funny things to BOTH front wheels while in action and probably hurts more than helps in a situation like that.

 

Haha. Mahout was the one that convinced me that we lose dynamic camber in a roll.

I'm sure J's and Spoon had more modified than they were telling us (in terms of suspension) to make everything work in harmony. I've seen some of their spring rate choices for the GD and GE, and am very curious how they came up with them.