CaliMR

iTrader: (1)

As track season approaches once again, I have a question about something that I was not able to figure out last year.

In the fast sweeper turn 2 at Thunderhill (especially when running it backwards), if I go through full speed (at least it is full speed for me ) and I am able to keep it from understeering too bad, the tires do the usual "weee" then as I pass the apex and put the power down it changes to more of a "weeee bup bup bup" kind of noise, and it can definitely be felt when it bups.

I am on Potenza RE050PPs and I have tried pumping them up to 45 lbs cold because I though it was just the tires rolling over, but it still did it in that corner and it felt like **** everywhere because they were over inflated. I also tried lowering pressure, and it still did it plus felt like **** everywhere because they were rolling over (tire scuffing on sidewall confirmed).

Evo IX MR, bone stock except the tires.

Am I just running out of grip? Usually when I run out of grip I end up in the grass and learn my lesson, but this seems different because it does not throw me off the track. If I just ignore it, I can drive through it, but then when I get to the next corner I slide through it like I am on glass. I am guessing that is over heated tires caused by the bups.

Anyone have any idea what I am doing wrong, and how to fix it? Would a rear sway bar help with this? (I know many people don't like just a sway, but I am not prepared to do coilovers or front sway yet) Or better tires? I am really not fond of the 050s but they just refuse to wear out.


Thanks

Evo_Someday

I used to have that same tire (RE050 pole position) in a 235/45/17. Mine rolled over bad. They also got very slippery when they got hot and didn't hold grip. There are better tires with better grip and better sidewalls. Perhaps that's what you need. I now run Z1 star specs in 245/40/17 (for autox) and really like them. I also notice a nice improvement in grip and handling.

The stock suspension is really just too soft for this kind of driving. You get what you get until you upgrade it.

MATT@WORKS

I don't think its rolling over on the tires but it is fairly hard to tell just by noise. Rolling is much more of a feel thing and a tire temp thing. Most Evos do run too much rear bar without adequate front camber and I imagine your car is doing the same. All stock cars roll out on the sidewall and camber plates are the only thing you can do about it.

As far as the sound, I think its just the bumpiness of that turn you're hearing. Tires should never really hop unless there's a damping issue.

Sideck

iTrader: (27)

i have that tires and no problems....

GTisRule

iTrader: (5)

Are you completely out of grip and you hear the tire chattering on the track surface? If I completely ignore what my car's telling me on the track, I could get severe chatter back with the stock suspension on a stock alignment. I've moved to coilovers and a lot more camber now, and it's seemed to of killed the chatter.

CaliMR

iTrader: (1)

That is what it seems like to me, but I am a track noob. If I back off a bit, it does not chatter.

MATT@WORKS

Grip is kind of a bad term to use. Lack of grip is the symptom of something, and just changing to coilovers isn't a great way to explain a fix. That is correct though, that the chattering is you probably pushing too hard with your current setup. If you feel like the car can grip more, and it's starting to lose traction prematurely, for one reason or another, then you start changing things, coilovers or not, to solve the problem.

My recommendation is that as a "track noob" you should spend more time trying to find the limit of the car/tires without any changes. Adding grip before learning the driving tricks to avoid exceeding the tires' limit can induce some pretty bad habits.

Once you know how to hit that point of track perfectly, then you can start playing around with tweaking the car to find some extra grip. The fastest drivers in the world are usually the ones that started out learning how to make the less-equipped cars go like the well-equipped cars. Once they learned the formula, they were blisteringly fast in cars that do have the refinement that REALLY high speed requires.

CaliMR

iTrader: (1)

Matt,

I appreciate the advice. I am actually not planning on changing anything with the car, but rather experimenting with my driving technique. The Evo is already a lot faster than I am

I may stop by to pick your brain if I see the Works cars at the track again.

MATT@WORKS

Laguna Seca Hooked on Driving event on the 18th... I'll be there coaching and trying out the revamped Works Time Attack Evo VIII. Sign up (if you can) and we can work with you on your driving and on your car.

The factory Evo alignment is pretty poor and is basically made to induce understeer and associated sloppiness. If you feel like it may help after you get the hang of things, we can show you how to use a better alignment and how to properly use tire pressures/temps. As I implied before, the stock car is a very good tool (if maybe just tweaked) to learn the limits of tires, the next step would be learning how to tune the car to use the tires effectively.

CaliMR

iTrader: (1)

I can't do that event, I am on call at work that whole week

I usually just do NASA because I have friends that race some of the spec classes, though I am not going to make Sears Point this month either.

18bora

iTrader: (8)

http://www.youtube.com/watch?v=P0jMD...e=channel_page

Was it going Weee Weee like a cop car? J/K
I had the same problem when my tires were new (full tread) and stock suspension. I think the full tread is what making the noise. Regardless of how much air I pumped into them, they kept rolling over. The stock suspension is just too soft. Like others said camber plates should help. I got a sway bar in the back and it helped keeping the back tires from rolling over, but the fronts were still rolling.

MATT@WORKS

A rear sway bar will make front tires roll over even MORE. Definitely need camber adjustment, that's the only true way to stop them from doing that. Once you have the ability to match your tread angle to the road surface, you can worry about sway bars for balance and spring/shock stiffness for fine tuning.

CaliMR

iTrader: (1)

I am just going to adapt my driving to what the car wants, rather than mess with adding stuff. Evos are too expensive to race, so I am planning on building a spec E30 to take over track duties anyways.

MATT@WORKS

That's a REALLY good idea. You can learn SO much from an E30. My first track car was a little E30 as well. I just instructed at a Hooked on Driving event where Eric Diamond brought his $0.18 E30 and I had a BLAST! It was a phenomenal experience for everyone that got to take it out on the track.

CaliMR

iTrader: (1)

I have several friends who race E30 spec and I am also friends with one of the local shops that builds them so it seems to be the most logical way to go. You can really beat on them and they just keep kicking, plus they are pretty simple mechanically so I figure I can do most of the maintenance myself. I rebuilt an old 2002 with a buddy so I have an idea how older BMWs go together.

My bike is going on Craigslist in spring, and that should give me enough to build the car.