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Rear end sways under hard breaking

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Old 04-21-2014 | 04:05 PM
  #16  
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Originally Posted by 996FLT6
Safety equipment ie seats/half cage/Hans is what I would deem mandatory if u planning to do many trackdays. If u doing 22-25 a year - that's priority no.1 Mike
Thanks Mike – that’s also the sense that I'm getting. I really do want to learn, but this is also (or can be) serious from a safety perspective. So, that’s the conundrum... do I turn my street 996 with a luxurious interior into basically a track car by ripping out the seats and putting in a cage, and god only know what I need to do with suspension.

Here’s the question – do I turn my street car into a track car OR do I DE my street car for 2 years and then just get a track car (the OP’s question) ? And, if the latter, are there things that I should be doing to make sure I don’t blow my street car up (oil scavenge issue I’ve read about) ?

Interested in thoughts as you are all much more experienced in this than I am. Thanks.

Last edited by ELange0322; 04-21-2014 at 04:24 PM.
Old 04-21-2014 | 05:29 PM
  #17  
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There is no perfect street / DE car. GT3 is close, but still not perfect. That said, any Pcar can be a great DE car. Pcars, including 996, are very reliable on the track. Drive what you can afford and enjoy it. There is always something bigger, faster, better. Unfortunately, the HPDE hobby implies some chance of vehicular or bodily harm every time you go out on track. When faced with your decision, I decided to have a dedicated track car. But remember, it doesn't have to be another Porsche. You can learn a lot trying to hustle a Miata around with the higher HP cars.

If I had to chose a street Porsche for occasional DE, I would pick a pdk car. I think it's ideal for novice DE student b/c 1) you won't overrev engine, 2) allows new driver to learn braking and car control and not think about heel toe. Once your hooked on the hobby and $$ allows, then you can purchase the dedicated track weapon of your choice. If you want to master the 6spd, that's up to you. As you get faster, you will decide that safety equipment is mandatory(hans, harness, cage) and go-fast bits a necessary luxury(better suspension,tires, etc.)

Just my $0.02.
Old 04-21-2014 | 07:28 PM
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I have not been driving regularly at Thunderhill for a few years, but I have a lot of experience there. This includes PCA instructor training/certification in the pouring rain in my Toyota Tundra. I behaved... some of my friends... less so.

I hope to drive there 1-2 times this year... perhaps testing, DE or racing, or some combo.

I have had a variety of experiences with changed track conditions from year to year and event to event. These include bumps in new places and/or with new characteristics. In general, I find all tracks "bumpy" in my 911, but this is a relative term in my experience (my car weighs 1000 pounds or more less than a stock late model 911).

One of my local contacts who sometimes posts in these forums was CDI for GGR for a few years and drove a late model 911 very capably. He'd be my local go-to guy for understanding various car/track interactions that might be experienced at Thunderhill in a late model 911 in a DE environment.

The former PCA tech chair works at Rector Porsche. He has done alignment work for me in the past (a 993). He is also a highly skilled racing driver. Just one of many resources in our area.

Other parts of the country have excellent resources as well. I always suggest leveraging PCA for folks with Porsches interested in AX, DE and or racing. And my standard recommendations:

Secrets of Solo Racing (book)
Going Faster! (video)
How to Make Your Car Handle (book)
and Porsche 935: Moby and the Warhorse Gang (some interesting perspective on relationship between Porsche Racing in US and PCA).

- Mike
Old 04-21-2014 | 07:37 PM
  #19  
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I don't have any experience with oiling issues with late model water-cooleds driven frequently at track events. If I had one, I'd certainly tap into whatever local brain trust I could find as a starting point. PCA can be a good resource for gathering perspectives.
Old 04-21-2014 | 08:02 PM
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A dedicated trackcar is by far the best with the full plethora of safety aids put in it but u have to trailer the car. I think for a street/de car if u don't need the rear seats the half cage should suffice so u can have a better race seat with harness that keeps you're butt planted wo having to brace yourself on stock seats. I've done De's with stock 3 pts for many years but as you get more involved and participate more- I shoulda put that stuff in much earlier. But get a Hans for sure!!! Mike
Old 04-21-2014 | 08:30 PM
  #21  
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I have the same car: 2006 997.1 C2S. For combined road/track use, I suggest:

- Oil pan extension with baffles, to reduce risk of oil starvation. You might also consider not running tires stickier than NT01, R888, Sport Cups, etc.

- Roll bar

- 6-pt+ harnesses with head/neck restraint

- Track seats with decent lateral support for legs, pelvis, shoulders, and head. Consider Sparco Ergo, which has removable halos (http://www.sparcousa.com/product/ergo). Track seats make it harder to get in and out of the car, but aren't necessarily uncomfortable on the road.

- Transmission cooling pump (which can be switched on and off).

I have a similar issue with sway under heavy braking, despite having a relatively new factory LSD in the car. I have a bit of front toe-out, and plan to try reducing that to zero to see if that helps. But as others have noted, sway can have various causes.
Old 04-21-2014 | 08:44 PM
  #22  
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Originally Posted by Hella-Buggin'
Hello everyone,

I'm kinda new to the DE events and have done about five so far.
I'm finally getting to the point where I'm staring to feel there are some areas where either my technique or perhaps the car are becoming an issue.

I have a 2006 997s with no mods with mentioning.

Here's the scenario...

I was at thunderhill a few weeks ago with the PCA and I noticed that coming down the back straight at about 110mph, once I got on the brakes to slow for turn 14 the back end seemed to get light and sway from side to side. Obviously the rear bias is a factor but I haven't felt it do the side to side wiggle like that before. It seemed to be repeatable and it seemed better if I didn't get on the brakes as hard but eased on.
I wasn't getting into ABS territory so I'm wondering if this is something I'm going to need to learn to drive around or is it something that can be tuned out?

A friend mentioned that perhaps the weight shift forced the rubber bushings to pivot and cause toe adjustments from the rear end.

Thanks,

Mark
Happened to me as well the first time I tracked the 997. The fix was to lower the air pressure which had risen to about 50 PSI. No LSD installation needed.
Old 04-21-2014 | 09:29 PM
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Your 2003 996 C2 is a great track platform to start. I'd head the advice on here around safety equipment, a racing seat/harness/Hans and a cage will be a great investment. I was thinking about your instructors comments on the shocks and actually wonder whether your Sport Cups got too hot...If the pressures get above 35 psi on these they get skirmy so check them after a run and see, that could be your issue

However given the number of days your planning I think if your running stock suspension you'll want to upgrade at some point..the $1100 RoW M030 setup from Suncoast in Florida is good, I installed this and found the track handling much better but road manners were still very good, I figured Porsche invests millions in R&D so why not take advantage of that rather than trying to choose my own setup from another manufacturer. If you want a real track setup there are a whole bunch of coilover options, PSS9's seem to be popular and reasonable. Also find yourself a good local shop for maintenance and a place to buy rotors and pads as with that many days you'll be on first name terms, atleast for pads especially if you have PSM as you'll eat rear pads fast. I've since gone down the slippery slope and have just built a 2001 Spec 996 dedicated track car but it took me a few years in my other 996 at DE's to improve my track skills.

I noted your in NY so if your attending he Metro NY Glen event i'll be there and happy to share my experiences for what they're worth

Enjoy!

John
Old 04-21-2014 | 09:50 PM
  #24  
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Originally Posted by Manifold

....I have a similar issue with sway under heavy braking, despite having a relatively new factory LSD in the car. I have a bit of front toe-out, and plan to try reducing that to zero to see if that helps. But as others have noted, sway can have various causes.
If the car is lowered and camber cranked in with stock rear toe links you will be at the end of adjustability and can get what effectively is bump steer toe changes in the rear of the car. Less of an issue with a highly sprung car but with stock spring rates of the OP the effect is more pronounced under braking and can lead to a "wobbly" tail into the corner...
Old 04-21-2014 | 11:18 PM
  #25  
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The back straight at Thunderhill is smooth but it does crest and then have a slight downhill on the braking zone.

I have two small kids and can really only get about 6-8 Track days a year at this point. I'm in the Green Group and usually choose to hang in the back of the pack. I have plenty of speed left in my street tires before considering NT01's and I would have to agree that at that point a bar needs to be in place. I think my next expenditure will be for a decent seat as I just have the standard seats in my car and it's a workout to keep planted.

I don't think I could do the PDK. I love shifting and nailing that heel / toe downshift. I know it's faster and smoother that I will ever be but that's not my concern.
Old 04-22-2014 | 09:44 AM
  #26  
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Manifold and hollmat - thanks for your comments. Will start looking into the roll cage and seats with a 6-pt ASAP, and also consder the suspension upgrade. Unfortunately, will not be at either of the Metro NY Glen events as have other work and then DE conflicts on those dates. Thanks again for your thoughts.
Old 04-22-2014 | 09:53 AM
  #27  
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Buy a slow Porsche and learn how to drive it fast, then get a fast one. You will be a much better drive in the end, and probably save a tone of $'s as well.
Old 04-22-2014 | 10:11 AM
  #28  
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Originally Posted by ELange0322
Manifold and hollmat - thanks for your comments. Will start looking into the roll cage and seats with a 6-pt ASAP, and also consder the suspension upgrade. Unfortunately, will not be at either of the Metro NY Glen events as have other work and then DE conflicts on those dates. Thanks again for your thoughts.
A roll cage is better for safety, but fairly impractical for a car driven often on the street. A roll bar will provide some safety benefit, and IMO is worth putting in, but note that A-pillars (at the sides of the windshield) can still fail.
Old 04-22-2014 | 09:06 PM
  #29  
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Originally Posted by por944s2
Buy a slow Porsche and learn how to drive it fast, then get a fast one. You will be a much better drive in the end, and probably save a tone of $'s as well.
Completely agree with por944s2. Consider keeping your 997 a street car and find a quality air-cooled 911/964/944 example to learn how to drive and get the most out of the limited HP on the track. As you get faster you will want all of the safety features you can afford and once you slip into a a good Recaro or equivalent and track-specific suspension, you will be thrilled on track days but not so much on your commute to work with that setup. See if you can get someone with a nanny-free 911 to let you ride in the right seat for a session at your next DE and you will see...
Old 04-23-2014 | 12:07 AM
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Or a really nice 993 track car - like mine (which needs a new home).


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