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Oh, sorry to see that, Patrick.
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Old 05-04-2012, 11:04 PM
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Originally Posted by 333pg333 View Post
Interestingly...or more confusingly, I've just been re-reading a paper prepared by a suspension analysis expert who went over another 951 (which also has all Racers Edge aftermarket components and Moton Clubsports) and who had 800lb springs all round, and his suggestion was to move the rear spring rates up to at least 1200lbs. This car has no added aero nor even a front splitter. He nominated a number of other modifications to be done to help with roll center, bump steer, scrub radius, force application point etc.... The frequency ratings are 3.25hz (f) & 2.34hz (r) with 800lb all round. By moving the rears up to 1400lb which he also didn't rule out, the rear ratings would come up to 3.10hz.

So it's interesting what different viewpoints you can get. The guy spent a full day in the workshop doing all the measurements on this car so it wasn't a cursory glance and pulling figures out of the sky type thing. I'm not saying I'm going to do the same thing btw. Quite possibly the opposite yet this suspension guy would think I'm crazy based on his recommendations.
oh yeah you have to do all the measurements to get suspension freq. I've always been told the 3 cycles per second is the upper ends of how stiff you want to go, but I'm not going to comment agaisnt what that report had to say. I'm sure that guy knows WAY more than me anyways! haha

But you know I'm just a weekend racer, on a smooth track I believe my car with a 3 CPS suspension would be faster, but I'm more comfortable with the setup I currently have.... plus i like to drive my 911 on the street so its not like I'm gonna put 31mm bars in anyways haha. I do have to say though that I do have plans to delete the tbars and go with a coilover suspension so I have more flexibility for track day tweaking, we get some pretty rough tracks here in the southwest, and somedays I would like def appreciate a softer setup

Thats the great thing about a coilover system like you have, if you know your gonna be on a real smooth circuit run the big boy springs, if you know its a choppy course it takes what 3-4 hours max to switch out to a softer spring and dial in a new alignment (depending on how skilled the guys helping ya out are haha)

I hope you got no chasis damage out of it though, looked like the panels where just a bit banged up, you got it laser aligned yet?
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1985 Carrera: Big Reds = Ass Saver

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Old 05-04-2012, 11:19 PM
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Yes a bit of a mess. Haven't done more than look at it so far. That's bad enough. What stood out was seeing it with post crash eyes on and I tend to agree that the rear wheels/tyres don't look as if they have much travel when sitting on the hoist. This is in line with the builder and engineer. So we will have to check the shocks to see that I've been delivered the correct product and see what we can do about them in any case. By the sounds of it the shop won't be able to start in on it for another 2-3 weeks. More agonising...
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Old 05-05-2012, 05:15 AM
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Yeah stiff rebound wouldn't have helped you out any
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1985 Carrera: Big Reds = Ass Saver
Old 05-05-2012, 06:52 AM
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Man up, Patrick! Opportunity out of chaos!

After my recent wreck, I'm standing on the other side of the armco with the other driver and his instructor (I should have been in a more advanced solo run group- these guys were still learning a lot, which is what caused the accident). I ask them what happened. I asked if the driver needed a ride home. Then I turned back to my car, started assessing the damage and formulating the rebuild. By the time the ambulance drove us all away, I had a plan to make the car lighter and faster.

I should have a running car by next week and the new body panels installed by the end of the month. I gunning for 2600lbs. No headlights, all fiberglass replacements.

I know you just spent a boat load of money getting that beautiful machine in perfect shape, but if the chassis is still good, I'm sure you can find a way to make the car even better! Heal up and get to work!
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Old 05-08-2012, 02:07 PM
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Quote Also to note the car was running on 10.5" x 18" 285/645 front and 11.5" x 18" 305s rear. Brand new Hoosier R80 slicks. Also while we had a pretty decent front splitter on we haven't had time to put on the large rear wing so have only had what is known as a Hoop spoiler from the Factory. This could also have affected the balance front to rear. UnQuote

You were very smooth going into that corner and the minimal correction you made doesn't look to have caused what happened next. With such a stiff setup absence of the "big wing" is likely a big part of the issue. How much down force is your wing good for at 145mph?

One of our buddies had a similar experience going into turn 2 at Infineon following a very fast driver with a big wing that he didn't have.
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Old 05-08-2012, 04:16 PM
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I crashed my 944 at the Daytona bus stop, 2 years ago. I haven't been back, since it was a planned "last race", to concentrate on my 911 project. To this day I re-live that crash in my head wondering if I could have gotten out of it, just by flooring the gas, while I was sliding through the grass, ready to side-swipe the tires. I'm sure if I would have gotten back on the track I probably would have forgotten about it by now...




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Old 05-09-2012, 07:54 AM
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The thoughts of the engineer is that the big wing will definitely stop this same issue from happening but will be masking the cause. In addition it will add a lot of drag and possibly reduce laptimes. Until I put the 3L racemotor in I might not put the big wing on...not sure. Still a lot needs to be determined before these decisions need to be made.
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Old 05-12-2012, 06:26 PM
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Quote:
Originally Posted by 333pg333 View Post
The thoughts of the engineer is that the big wing will definitely stop this same issue from happening but will be masking the cause. In addition it will add a lot of drag and possibly reduce laptimes. Until I put the 3L racemotor in I might not put the big wing on...not sure. Still a lot needs to be determined before these decisions need to be made.
Thats some easy real world testing though, if you can find a place to do a standing mile run it with and without wing, you'll find out the real drag coeffiecent added to the car.

Also I remember some years ago Road and Track doing a standing mile between a bunch of race cars and track cars, lola champ cars, ruf yellowbird, jaguar race car, a ducati, lambo, so on

When they took the rear wing off the Jag to try and get it faster in a straight line, it actually caused the rear to be so unstable at speed they weren't even able to go as fast as with the rear wing on

and btw's the RUF was still the fatest car (MPH not time) through the standing mile haha (the Lola took top time if I remember)
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1985 Carrera: Big Reds = Ass Saver
Old 05-12-2012, 10:29 PM
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Back to your initial question - what to do when you have lost it beyond "both feet in?"

Grabbing the shoulder harnesses as Danica did is a good thing. Keeps your hands off the wheel, where they or arms might be injured if you are holding with stiff muscles and a death grip. Also keeps your hands from flying around, or at least helps prevent that.

When I raced at Texas Motor Speedway we were all told that if we started losing it on the banking we ought not to turn into the spin to try to catch it. Rather we should turn the car down to the bottom. That was our only hope of keeping it out of the wall.

Vic Elford gives similar advice in one of his books. Followed by one extra piece of advice, supplied by Dale Earnhardt to the road racers at the Daytona 24 hours driver's meeting: "Closing your eyes is optional."

When traction is way below what is needed, I don't think spinning the rear wheels is going to help at all. I think you are basically ballistic at that point. I know of a nasty wreck where the driver, up in the 130 mph range or more, appeared from the data to be trying to drive out of it from the point he got off the asphalt (at which point he hadn't really spun, just had a bump set him off what otherwise was trackout onto a short straight. Rear wheel data showed 120 mph at time of impact, and this included a 3/4 spin (so he hit right rear quarter at a 45 degree angle pretty much), and passing from damp grass over a wide (NASCAR width) concrete segment of an oval not used by the road course. Entered that at less than 90 degrees and continued to spin to the final 135. I'd have thought that concrete would slow him way down, but unless he wasn't braking (there were skid marks all the way), it didn't.

I had a slow motion experience at Heartland back when the course used the dragstrip. Track was damp, and I was trying to see how well my then new Michelin Pilot Sport Cups worked in the wet on my SC. Not especially well, I concluded. But I was working up speed some, while being especially careful entering the drag strip where they spray that black stuff which increases dry grip I guess for drag racing, but which has the opposite effect when even a little damp. Car started to spin just after I completed the turn and was going straight, and mostly in mid-track where there was some untreated concrete. It was like on ice, with slow rotation. I tried braking, not braking, goosing it, coasting. Nothing changed the inexorable base course of my several 360s toward the left side wall. Luckily, by the time I backed into it I had slowed a lot, so it was a gentle hit. Because I have stock rear bumpers and bumper blocks, there was no damage. But not due to anything I had done after the spin started.

But I wasn't going fast enough at any point to be afraid of injury. My worries were my wife would kill me because she was racing the car and just didn't want to drive in the wet in practice, and was I going to get a 13 (bad old days of PCA CR where single car incidents with damage led to one). She didn't, and I didn't.
Old 05-13-2012, 10:06 PM
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