chinook527

I just finished my first autocross in St Louis and did pretty well. My best time was only 2 seconds behind a Lotus Elise, but it raised some pretty ugly handling problems with my TII.

I have an 88 TII, stock wheels and rims, upgraded sway bars, tokico shocks, and lowered about 1 inch. I ran 38 PSI front and 34 PSI rear to keep understeer to a minimum. It didn't work. The car just plowed through every low to medium speed corner thar required power to get through. This caused me to slow down to stay on course, which dropped RPM, spooled down the turbo, and killed my exit speed. The slalom, transitions, and braking turns were all ok. I tried some trail braking to turn the car, but you eventually had to get back on the throttle to keep momentum going. I felt pretty smooth and fast everywhere else, but I probably spent 2-3 seconds per lap waiting for the front to turn in.

I am disappointed, I thought my TII was better than that. Please help with my push problem!!!!!!!!!!!!!!!!

Mike

rotorette

We had the same problem when we started with our 1st with a T2 swap. A couple things that helped:
1. Buy good tires!!! We got falken azeni 615s - this helped us improve more than anything else.
2. Coil overs
3. If you can, have an experienced driver walk the course with you and give you tips on where to brake, lift, accelerate and ask them about ways to help with the plowing
4. Slow down on the big corners - a lot - brake in a straight line before the corner - it will feel really slow - but will be faster in the long run because you will keep the right line - I still need to work on this.
5. Other things that we don't have yet, but plan on is turn-in spacers, camber adjustment.
6. Practice

Hope this is helpful. Good luck

DamonB

If the car seems to plow in corners following a braking zone you're most likely braking too deep into the corner. Get more of your braking done sooner before turn in and see what happens.

If the car corners well until the last portion of the turn when it pushes as you get back on the power it's the weight transfer off the front that's getting you. Try to get on the power earlier, smoothly-er and slowly-er. You'll only be able to do this by entering a little more slowly and getting more of your turning done early in the corner. If that doesn't help go up on the rear tire pressure and see if that will help the rear end rotate.

If the car turns well in medium and fast corners but plows like a pig in slower ones it could also be from the larger front swaybar. This is unfixable; you have to drive around it and be patient in the slow stuff. The payoff is that you make up for it in the medium and fast stuff.

If the car loses boost, downshift. If the course won't allow a downshift you have to accept you're driving a turbo car

This was your very first autox so most likely your problems are self induced. No biggie; those are the easiest to fix. Try some of the above at another event and see what happens and ask some of the experienced guys their opinions. Since it was your first time and you were being aggressive you were most likely braking too deep.

chinook527

Thanks for the quick reply. One turn was a high speed sweeping entry with a late brake zone. This was the cars best turn, the back end responds well to trail braking and rotated nicely to setup for the exit. The real problem turn was a increasing radius turn after exiting a mandatory slalom. You couldn't carry extra speed into the turn for trail braking, so you were stuck with a smooth entry and accelerate all the way out of the turn. It was at this point the front would start to push.

All of the turns that I could throw the car into (late braking, transitions) were good. Constant power in the slalom worked well. The smooth turn to an exit with full power was the only problem. While I was a rookie, I wasn't killing cones and getting lost like some were. My lines were spot on 90% of the time. The car just suprised me that it would not respond to a smooth turn. It really liked being overdriven, and responded well to late braking.

My SCCA tuning card says to raise front and lower rear tire pressures to correct understeer. What is the optimum tire pressure, and how far can I deviate from it during tuning before going too far. Does more pressure add or subtract traction from that tire????

Valkyrie

I could have sworn that raising tire pressure gives you LESS grip, but for obvious reasons, you can't just run them with super-low pressure (except for some racing tires which run at like 16 PSI) because they don't work well like that...

If you want an example, go drive a bike that has highly-filled tires versus one with low-pressure tires. The one with highly-filled tires will roll better, but the one with less pressure will have a smoother ride, and more importantly, have a lot more grip.

I'd try 32 all around, although raising the pressure before you go to an event is usually a good idea so you can bleed off the pressure when you get there, since you might not have access to a compressor.

Or, start high all around, and then bleed it and see how it changes how the car drives, and then find a setting you like.

FYI, a stronger front sway bar will induce understeer, while a stronger rear bar will induce oversteer...

(and if you can't get the car not to push, you're gonna have to just shift weight to the front so it'll turn. Lifting off the throttle or braking will do this...)

DamonB

The problem with such "rules" is that they don't take into account what pressure you're starting from; it's all relative.

To get in the ballpark on tire pressure you want to see the wear pattern on the tire coming an 1/8" to a 1/4" over onto the shoulder of the tire. You can mark the tire with a dab of shoe polish or chalk to check this. Adjust pressures in big chunks (about 5 psi) at both ends of the car to obtain this wear pattern while ignoring the handling at first.

Once you've established what the front and rear pressures need to be then you can start adjusting them to make the car behave differently. Most likely at this point the car is already going to be acting differently than it was. Get the pressures in the ballpark first and then see what the car is doing.

Icemastr

iTrader: (2)

I would worry less about what to do to make the car handle better and more about getting some practice. It was your first even and if you are an aggressive first time driver your are going to understeer a lot. As a novice chief for 2 autocross organizations I ride with beginners several times at 18-20 events a year. Most people can fit into one of two types their first event or two the unaggressive ones who just drive slow and won't push the car and the overly aggressive ones who push hard into nearly every corner. Usually the overly aggressive ones who take tips and learn from their mistakes I see the most improvement in but when they first start it seems like their car is understeering into every corner. Some think its the car and want to know how to make their car handle better, others realize they are pushing too hard and they need to brake sooner.

There is nothing wrong with learning how to adjust your tire pressures but focus on taking the corners correctly and try playing around with adjusting your pressures to learn how changes will affect things. After a couple more events take your car in to get an alignment done, you might find out your car has serious alignment issues, if not you should still be able to make a large improvement in your cars handling by adjusting your toe to give you slight oversteer and the camber to give you more grip in corners.

dgeesaman

iTrader: (7)

I have a few related questions that may relate to the OP as well. I find that pushing in the corners is simply a matter of taking in too much speed, and that I should slow down earlier to allow for a later apex.

I feel there are parts of an autoX course where getting low on the RPMs really hurts the exit since the turbos aren't spooled. I *think* that advanced drivers use left-foot braking and light throttle to overcome this. Is this correct, and how advanced is that technique (when should I start learning it) and how would I go about learning it?

It seems to me that simply driving for line, braking point, and balancing the car for max grip in the corner will go a long way for lowering times for now, but I had an instructor who believed that the earlier you begin practicing things like this, the more easily you'll be able to apply it.

Dave

DamonB

That's true and it works. The problem is that it is also very easy to do incorrectly or poorly and that will hurt you much more than just driving "normally". Out of all the people I see left foot brake I feel few are actually getting any payoff from it. For instance it's easy to overslow the car when using LFB and modulating the power is twice as hard because you're now using 2 pedals instead of 1.

Agreed. Until you're extremely consistent and have proven your speed without doubt against other very fast drivers over time I see no point in using LFB. There's no doubt when you get it right it works in some situations, but it's far, far easier to get it wrong.

I agree with the start practicing now idea but not with LFB. Fact is there are terribly fast people everywhere who don't LFB, so it's not a fundamental ability people need to concern themselves with IMO. Mastering the "simple" things will make anyone much faster than merely being good at those simple things and using LFB.

AMRX7

TII's are limited on alignment in stock form. You said yours is lowered an inch, so what alignment are you running? How much negative camber in front? What is toe at? I'd fiddle with alignment before changing parts.

-Andy

Icemastr

iTrader: (2)

I agree with Damon. The only top notch driver I have co-driven with or know of that uses LFB is Karl Coleman and I don't think he started out racing that way. Pushing the car to the limit, braking properly, and controlling the car are the things to be focusing on learning. As a beginner there is a whole lot of things to take in. I know it took about 10 events or so for me to get past the sensory overload and finally be able to focus on specific things to improve.

I also agree with Andy. Many people lower their cars without having an alignment done. In my experience I have seen huge improvements from fixing alignment settings.

rcefstsfecr

What was your time? Where did you race? Just wanting to know some basic information from another STL resident.

chinook527

Damon, sounds complicated but I will try that. I ran the pressures I did off someones recommendation. Ill give your way a try.

The solo event was July, 9 at gateway international. I placed 2nd out of 7 in the STO class. Had I ran in another class I would have been 85th, out of 120. Not bad for a rookie, but I need to sort out the handling problems or figure out how to drive around them. I was 2 seconds behind a couple of Elises and 1 second behind an experienced driver in a 3rd gen running much better tires. I think without the push I could have run 20 - 30 postions higher on index. That would put me up with the viper that was there.

Next event is July 23 at Gateway, look up James Elderman at SCCA.com stlouis chapter. He will hook you up, and get you started. Or just show up on the 23rd at 730 am , with $30 ready to race. It really is that easy. Just do it!!!!!!!!!!!

Mike

Bruceman

iTrader: (5)

Make sure you are not running out of suspension travel in the front. If this is happening your shock travel will be limited by your bump rubber. Riding on the bump rubber will overload the outside tire and cause understeer.
To check whether this is happening simply place a tie wrap around the shock shafts when the car is jacked up. Push the tie wrap all the way down the shaft before lowering the car. Then after an autocross run feel where the tie wrap is located on the shaft. If it is touching the bump rubber or gone entirely then you are bottoming out the suspension which will cause understeer.

Of course driving improvements come first before changing the car.

chinook527

I never thought of that, I will give it a try. The spring rates are pretty stiff, but anything is possible. It sounds like I am not the only one to have understeer in a 7. I just read another thread about a upgraded LSD causing a push because of too much lockup. All of these mods were done before I bought the car, so I don't really know what I have.

Mike

JAB89RX7

Seat time...Seat time...Seat time!!! If that was your first autocross, you are experiencing what everyone who is new to autocrossing finds out. It's a very technical sport and it's hard to get good at it. That is one of the great things about the sport, after 20 or 30 autocrosses I'm sure you will say that your technique was just not there on that first autocross. Normal driving is like minature golf compaired to a normal 18 hole course. You don't just go to a golf course and make par your first time out on all 18 holes. Things happen extremely fast in the sea of orange cones. One slight mistep in your line around a cone will compound into throwing your line off for the next 5. Understeer is the most common problem untill you learn how to correct it. Tires, tire pressure and a number of other things can contribute to it. Don't give up!!! Go to the next event, and then the next, and then the next. Talk to the experienced guys there and ask what they recommend. Autocrossing always seem to get easier and faster the more of them you run.

-Jeff
www.yamscarclub.com

mightymite

iTrader: (1)

i had understeer and adding a few psi helped only bcs the tire was folding

Kentetsu

I had the same issues with my fb when first starting out. I don't know what tires or size you are using, but your pressures seem to be very low to me. Using Sumitomo HTR 200 205/60/13s I run around 50 psi front and 45 rear. Use chalk or shoe polish as mentioned to mark the sidewall, then run a lap and see what the tire is doing. If the chalk is completely gone, then you are way too low. If the chalk shows that the tire is not rolling over to the edge of the sidewall, then drive faster...

MosesX605

It should be noted that the HTR 200s have a stupid soft sidewall and need insane pressures to keep them from rolling over. That's why they're actually rated at 52 PSI max pressure. Bottom line for street tires is that there will be some roll over, it's a consequence of the soft sidewalls built for comfort rather than performance.

Have you checked your front alignment yet? I don't know about TIIs but my SA came configured with 1 deg positive camber from the factory, which makes it push like a pig until the rear end binds and it steps out. You need to ensure that you have all the negative camber you can get and up your positive caster as well.