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I like to set the car up to be neutral or with very slight over steer with the rear tire pressures, then a slight tap of the brakes can induce the rotation I need and still keep the rear "catch-able".
 

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"R" comps will be much diff that street tires. I posted the pressures back in post #13.
 

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Not seeing a mk4 gti in the results...did you make it out to that event? How'd it go with the new suspension?
 

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Discussion Starter · #26 ·
Not seeing a mk4 gti in the results...did you make it out to that event? How'd it go with the new suspension?
I didn't make it out. I was hearing a front end clunk whenever I went over a speed bump or loaded up the front at low speeds. I checked my LCA bushings and saw that they were completely shot.

So I used that day to replace both LCA's. As much as I wanted to hit up the event, I decided that it might be a really bad idea considering the condition they were in. Also, I'm registered for a morning autoX school this Friday 8th, followed by an afternoon event. Since that means I'd be getting 50-60 runs in total for the day, I had to sacrifice the last event to get my car sorted for this Friday. Now, I can go to the event having a very crisp handling car that I can be confident in.


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Discussion Starter · #27 · (Edited)
So I did the school and event yesterday. I got a trophy for 3rd place which isn't too bad when you consider that everyone in my class were on slicks! But now I'm thinking that the thread should be renamed to "how to get the car to rotate." lol

The new suspension and tires felt great and there were several runs where I could feel the rear rotate perfectly, which is a very rewarding feeling. But there's one big problem: I'm not sure "how" I got it to rotate so well sometimes and not others. I don't think that I fully understand the physics involved in getting the rear to rotate. If you look at my times I was very consistent, enough so that I got the highest consistency points in my class. But I wasn't consistently getting the rear to rotate when I wanted it to. Any advice?

Also, I noticed several times that when the front was loaded up under hard cornering, when I would try to give it some juice, it felt almost as if the trans was binding up. Was this because I was asking too much of the car in those instances; is it because I need a better diff; or is it just crappy driving? Thx.


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Were you getting the car to rotate well in certain corners and not in others, or was it different run-to-run in the same corners? If it was in different corners then it's possible that the pavement in those areas had more/less grip or perhaps had some gravel/debris on them (not sure if the event swept the track beforehand, we used to when testing our Formula SAE car at school)

Did the car's rotation change somewhat continually through the day? It's possible that the track temp was changing and effecting grip.

Did you wind up getting a tire gauge? What were your readings like?

Take my comments with a grain of salt, as you may actually have more experience than me :laugh:

I'm not sure what you meant by your transmission binding, but maybe you want to invest in a stiffer transmmssion bushing? I got the ECS dogbone bushing upgrade a few weeks ago and really like it except when I'm idling, and especially when idling with AC on.
 

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Discussion Starter · #29 ·
Thanks for the reply. I Have less than 6 events under my belt, so I will check for some of the above mentioned conditions on my next outing (which isn't for at least another month since I currently have a broken foot).

I bought a good gauge and tried different pressures throughout the day at the school. I settled on 48psi on the rear tires: I didn't land on anything conclusive for the front tires though. But they were still rolling a bit on the sidewalls at 46psi. So I'm not sure what to do about that.

It terms of getting the rear to rotate; it was always a hit or miss affair. For example: the rear would rotate beautifully through the first slalom on one run, but not every run, or the rear rotates well through turn two sometimes, but not all the time. I always check my pressures between runs, so it's not due to changing tire pressure. Which leads me to believe that it may be my lack of experience/knowledge with the physics behind the car.



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what kind of tires are you using? because if they cant hold up at that kind of pressure then something is wrong
if your running really high performance street tires like hankook rs-3 or toyo r1r then you should be running mid 30s front low 30s rear mid 30s as well in the rear if you want a bit less grip for rotation
if running regular street tires you want up 30s to low 40s rear and low 40s front

mark your tire sidewall with chalk, etc
you should be rubbing the chalk off down to the tip of this triangle
 

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Stock suspension stuff may need 40- 50 front and up to 55 rear. If the car is inconsistent, you are probably gettting on the edge , per above post.
Or you may be trail braking into some sections only part of the time. Trail braking and/ or left foot brake can loossen up the car enough to go faster.
Sometime the car needs more air for the "turn around" , if your track has one. Many solo courses have a single pin of of some sort and really hurts the outside tire. , add air for this turn ,as it may help and long slow turn.

Optimal air may not be the same for all of the tires., or even left to right.
 

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Discussion Starter · #32 ·
I'm running Hankook V12's. I used Moroso Race Write and marked all four corners. The rears were fine in terms of rolling onto the sidewalls. It was the front that rolled past the triangle and across both those raised lines beneath it. At that point, I raised the pressure up to 46psi at the fronts.

I considered the idea that it may be a setup issue, but if that were the case then I wouldn't be getting the rear to rotate at all. I think that it's down to my driving and lack of consistency.

So I'm wondering: how should I be entering a turn and/or slalom? What are some the rule of thumbs to keep in mind when driving a FWD car with a rear beam? Any advice would be greatly appreciated.


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when entering a turn i brake hard right before the turn then gradually let off the brakes during turn in this puts alot of the load on the front tires which helps the front grip and the rear rotate

in slaloms i stay as close to the cones as possible so i dont have to make big turns which will quickly overwhelm the fwd
 

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Discussion Starter · #34 ·
when entering a turn i brake hard right before the turn then gradually let off the brakes during turn in this puts alot of the load on the front tires which helps the front grip and the rear rotate

in slaloms i stay as close to the cones as possible so i dont have to make big turns which will quickly overwhelm the fwd
I'll try that at my next event: Which probably won't be for at least another month unfortunately due to my broken right foot. But that's a really good tip.

I had tried doing something like that at my last event but found that my brakes were slightly inadequate. I worked the first heat and noticed during my run group that it was taking me a lot longer to drop speed at the corner I had been working than the previous cars had needed. I initially thought that it may be that I had more speed than them, but that's not the case cos I'm sure some of the Evo's were carrying way more speed than I was. So I may try getting Hawk pads and braided lines front and rear.


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im running stock brake setup with oreilly's 20$ pads i want to upgrade the pads but the courses we run on are sealed asphalt and is very slick as far as track surfaces go so even with my star spec tires brakes keep up with the tires grip
 

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Discussion Starter · #36 ·
im running stock brake setup with oreilly's 20$ pads i want to upgrade the pads but the courses we run on are sealed asphalt and is very slick as far as track surfaces go so even with my star spec tires brakes keep up with the tires grip
Wow, stock? I don't think I can continue to run stock. It seems that I have to get hard on the brakes and for a very long time whereas other cars only need to quickly jab the brakes on the very same turn. I was told that it may be because the car is so nosy-heavy (VR6).


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my car is one of the lightest mkIV the 1.8t wolfsburg edition plus i removed some weight and its now floating around 2800lbs so that may help but like i said the surfaces we run on aren't exactly idea
 

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Discussion Starter · #38 ·
I have an event coming up this Sunday: My first in over a month after breaking my foot. I'm going to try all that was suggested on here. Thanks so much for the input.


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It seems that I have to get hard on the brakes and for a very long time whereas other cars only need to quickly jab the brakes on the very same turn. I was told that it may be because the car is so nosy-heavy (VR6).


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Have you stood on the brakes hard enough to activate ABS/lock the wheels? If not, have you had an instructor drive the car or did one ride with you during the school?

Threshold braking is a much, much more rapid deceleration than you are used to on the street. A couple of new people I have instructed and one friend who was bedding in pads required a fair amount of urging to get beyond what they considered 'hard' braking that was actually quite mild for an autocross situation.
 

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Discussion Starter · #40 · (Edited)
I did have an instructor with me during a few of my first runs, but he focused more on my steering input than anything else.

To be honest, I didn't get into the ABS at all. So now that you mention that, it's something that I really should've kept in mind: In retrospect, it'll probably shorten my braking distance significantly. I've read about threshold braking but I never thought to apply it in an autoX situation. But it makes perfect sense. Rookie mistake I guess. I will definitely keep that at the forefront of my mind while walking/driving the course. Thanks so much!


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