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Second time to the track-help needed

Discussion in 'Race Talk' started by dwj, Jul 28, 2009.

  1. dwj

    dwj Member

    Tight, tight, tight. To quote the instuctor that took my car out for about 10 laps.

    Ran about 50 laps today (2.5mile 13 turn) and it just about did me in. I do not recall all of the info on this topic in the forum and figured I would start it again as they may be new opinions/facts. What can be done to get the LSC looser?

    My links are very close to parallel, pan hard is slightly pointed up to the frame side. Running 245 Kumho Ecsta on front and 315 on the back. 240 # springs on the back, 400# on the front. Front shocks set on 1 out of 16 and rear 15 out of 16. Big block. 34 # air in front 37 # in back.
    Camber -.3 degrees; caster 5 degrees; toe 0.

    I think I remember BP saying he went with 285's on the back and it helped?

    Any thoughts? or nature of the beast?

    FYI. There was a beautiful polished Kirkham that some youngster had, the instuctors were correcting the lines he was driving and he got mad and left.
     
  2. Is your car overly tight in the front or back or does it just slide on all fours?

    Your tire pressure looks quite high to me. I typically start out around 30 psi and continue to lower it as the day goes on. So far I have found 26 psi to be about right for my street tires on a race track. Depends on the track temp as well.

    Your spring rates are certainly in the ball park but they to require iteration. It is important to change these things and feel for yourself the effects.

    Having your dampers adjusted full on and full off at the front and back of the car seems a little strange to me. I would set both fronts and backs at mid-adjustment and then start playing with tire pressure. If you are still not satisified then you can start playing with spring rates. There are several threads on this subject. In-a-nut-shell you will likely run out of rear axle travel before you find a spring soft enough to avoid over steer. That is the nature of these cars I am afraid.

    Anyway tire pressure has a very noticeable effect on your cars handeling, is easy to change and probably the best place to start. Change one thing at a time if practical.

    I have a track day next week and am really looking forward to it.

    A boy or very young man driving a Cobra is an accident waiting to happen. I would sure hate to see a Kirkam damaged! They are beautiful cars when polished.
     
  3. dwj

    dwj Member

    Rattlesnakepete,
    Thanks for the reply.

    First when I said the Kirkam had a youngster, he was probably late twenties early thirties (youngster to me) with an attitude of superiority. The car had a motor that made my KC BB sound like a toy. My guess would be it was more than capable of "Jody fast".

    The rear never thought about coming around the whole day and a few times the fronts lost traction in the between entry and apex and I started going straight. I had to let off the gas which of course slows me down and the rear comes up but does not slide around. I tried increased acceleration once during this and that was a bad idea.

    Shock set-up. Not the first time i have done something considered strange.(chuck of vinyl ester with 600 HP) I have varishocks which have 1-16 adjustment that does both compression and rebound. On the rear, they are in the lower mounts which gives me about 2 '' of travel. At the max adjustment I almost bottom out the shock, I hit the chassis stop with about 1/4 '' left of shock and then compress it a little. On the front I have about 2.5 " of travel and with the minimum setting I came within 1/4" of bottoming out the shocks.

    I figured higher pressure in the back tires may loosen it up??

    The first time I was at the track I had the lower links parallel to the ground and the upper links pointed down towards the front. (drag set-up) This time I had the uppers parallel to the lowers and it seemed worse. This set-up does ride better on the street .

    I had the instuctor drive it to make sure the probelm was not all driver. He would enter the turns slower than me and accelerate a little harder than I would. He still considered it way too tight.

    The nature of the car is what I am trying understand. Do not want to do drastic surgery, was hoping there is something completely out of whack I could change. Will increasing the settings on the front resulting in less travel help? Next time I am at the track I will play wilth tire pressures. The reason I did not last time is I figured it would result in minor improvements that could be offset by my still inconsistent driving skills.

    Something I left out in my original post was that a nice lady in a Z06 was smoking me in the turns.

    I am a novice and will probably always be a novice but at the end of the day I was just tired of fighting the car in the turns.

    David
     
  4. CapnCrunch

    CapnCrunch Member

    Well, I have never been on the track but, in autocrossing, you want to come out of the turn the fastest you can so that you carry the increased speed all the way down the straight. That is where you make the most time so going into the corner slower is very reasonable especially if you come out faster...

    Good luck, we need more people racing the LSC so we can get the kind of knowledge base that FFR has.

    CC
     
  5. dwj

    dwj Member

    There is a local high performance shop that mainly deals with vettes and mustangs for the track or drag cars. They have a supsension guy that used to track race that willl go to the track with you and will drive, ride and make car adjustments for the day. Kind of your own crew chief. This is not a free service and I am going over there this morning to discuss. I have spoken with them before and I get the impression they consider my suspension "junk"

    It is what it is and a blast to drive, just got to figure out if I am missing out on something.

    Found a local FF cobra that wants to go the track next time. He has never been to the track.

    Couple other notes:

    I did replace whatever brake pads(LSC standard) I had with the Hawk ceramic, flushed with Motul RBF 600 brake fluid. I liked the feel of the brakes better and there was some improvement in stopping.

    Even know I raised the vent tube about 1.5 ", I still blew rear end fluid everywhere. I will put a hose fitting in place of the vent and run it into the trunk as BP suggested.

    Fot those thinking of tracking (or attempting to in my case) I highly recommend that your engine breathers vent somewhere other than on your valve covers and you route your rear end and maybe transmisson vents into a puke tank. If you don't , the underneath of the car will be an interesting mixture of fluids and your engine compartment will have a fine coat of oil. Throw in all the bugs and rubber stuck everywhere and you have 2 days of car cleaning.
     
  6. David,

    Sounds like you have good parts to me. I very much like the varishock, though I have QA1 which are fine as well.

    These cars are crude by today's standards, especially when comparing to a Z06. But like you said, really fun to drive. It is almost like a wrestling match at times!

    The fact that your rear end does not come around ( swap ends) is a very good sign. Oversteer in these cars is typical and can cause the most damage to you and your car. I would gladly live with a little push in the front compared to swaping ends ( which I have done more then once on the track).

    Your damping adjustments can have a large effects just as tire pressure but are usually more complicated to tune. Having the two way adjustable it a good benifit in my mind. I bought the single adjustable because I thought it would be too many variable to have the two way. In hind sight I wish I had the two way because I am learning that I want to stiffen extention more then compression.

    I highly recommend Carol Smiths books on race car handeling. They really helped me get a better understanding of what all of these adjustments( springs,dampers, tires, roll bars) do and how they interact.

    Like Captain Crunch says, please continue to share your lessons and experiences. I am very interested and will do the same.

    PS If you decide to play with tire pressures be sure and check them before and after your session. I usually pick up 3 to 5 psi after a 20 min. session due to heat. Three to five psi is a very large change in tire pressure and can most certainly be felt on the track. If my target is 28 psi I will usually start the session at 26 psi and it will be 28 to 29 psi after 20 min. on the track.
     
  7. BPWilliams

    BPWilliams Member

    Well sorry I have not been looking at this site much now that I am messing with the Camaro. In AZ it is 115 and we do not dive our Cobra's much in this weather, they might melt.

    Pushing is much safer than being too loose, but the trick is to find the happy middle place. I was surprised about two things...

    1) Shock settings - you have the rear stiff and the front soft which should make it loose, this is not the case.

    2) Tire pressure - You had 37 in the rear, and 34 in the front, way too high for both, but with more in the rear it should have also made it loose. which was also not the case.... :shock:

    I would think that there is too much tire on the car but only checking your tire temps would prove that out, Harbor Freight has a chepo temp gun and you can get them on sale for $29.00 if you catch them at the right time. I would start a log book with all of the changes as you start to step through this process.

    Start with the front tire pressure, lower it until the rear starts to free up. keep checking your tire markers to make sure that you are not letting out too much air. Do that first to see if you can make it loose, see if the car is capable of getting loose.....?

    AND As CC said "Slow in = Fast out", so slow that baby down on corner entry and get on the gas faster.... Corner apex! Let us know how it works out for you...
     
  8. dwj

    dwj Member

    Went to the performance shop this morning (more important than work).

    It turns out they set up the yellow Z06 I referred to earlier and they said I will never keep up with it. Now that is out of the way.

    Following is a list or stuff they want me to do and test before we even talk about them coming to the track with me.

    1. Get a new drivers seat. I am too small for the current and the location of the harness means I am unabale to get locked in good.
    2. Add a dead pedal for left leg bracing
    3. adjust the shocks to 60/40 extension all the way around. Set damping at mid point.
    4. I was incorrect with my panhard postion in the earlier post. I am pointed down at the frame mount. I will relocate to the upper hole.
    5. Put lighter springs on the front. I own a pair of 320's. This seems contradictory to what some of you guys did.
    6. Buy a tire temperature guage. This will tell them a lot about the balance of the car. (Suggested in a couple posts ago)
    7. Turns out I have the front master on 7/8 and the rear on 3/4. I will switch those for now and get a tilton 7/10 for the front and then move the rear back to 3/4.

    There was some talk about creating new mounting options for the suspension. Any thoughts on my plan of action??. The good news is that the above is not much $$$$.

    I nicknamed my car 'The rocket" my wife calls it "That stupid Cobra".
     
  9. Roush #1

    Roush #1 Member

    One thing that has not been mentioned is to be sure your springs are what you think they are. Just because you changed from a 350# to a 300# spring doesn't always mean you went down 50#. My experience with springs is they are not even close to their rating numbers.

    One more thing you need to do is to take a lot of good notes now with the car pushing because at some point - I promise - you will want to get that push back.

    Please keep us informed how you get a left dead pedal installed as we all would like to have room for that.

    On my car, leveling the panhard bar was the single most effective change to increase driveability - on the street and the track.

    Good luck and thanks for sharing your experiences with us.

    Jody

    BTW...anybody can drive a car with traction control and anti-lock brakes, but it sure is fun when you go Jody Fast and pass them without either one :wink:
     
  10. BPWilliams

    BPWilliams Member

    Just tell that Yellow Vette to come on down to Arizona and we will take a couple of laps on any track here that NASA races on, I will point my camera backwards so everyone can see it.

    I am really, I mean really confused.......

    Now you are saying that in fact you have softer springs on the front? This should induce even more oversteer (loose) ????

    OK, back to basics... I would check the entire suspension and make sure it is not binding anywhere, anyone seen that 3 legged Cobra? I would make sure all of my settings are correct (for your case stiff rear (never thought I would say that) and soft front) and write them down.

    Then I would go out on a session and lower the front tire pressure and see what happens, if it gets better check the tire for alignment to the tire marks.

    If the tire marks are close I would increase the shock rate in the rear and see how that works, make notes on what happens.

    If you are maxed out on the rear shock and it was getting better, I would go to the front shock and decrease the shock rate. By then the rear of your car should be happier than a whale in a plankton farm.....

    If this does not free up the car just add air pressure to the back tires until they are rocks and that will do it for sure..... :roll:

    Good luck and these cars are a challenge to drive to take baby steps and be safe. The continued thrill is far better than the one great lap and kapow!

    PS do you have a front sway bar? if so what kind and rate?
     
  11. dwj

    dwj Member

    BP,
    I am tight(never been to prison), understeer, push, plow, whatever. Trying to loosen the car up, give it oversteer. Jody said to take good notes becasue evertually I will want some understeer back.
    dwj.
     
  12. kenwat

    kenwat Member

    We need to get together. My car is so loose I spin out on just about any turn. But that's parking lot SCCA. I might do better on a fairly clean race track. When are we going to MSR again?
    kenwat
     
  13. dwj

    dwj Member

    Kenwat, be hard for you and I to get together, I am north of Minneapolis. We made it the month of July never hitting 90 degrees.

    I took a zillion measurements and am going to make a spread sheet to keep my changes straight. One problem I have is the body is skewed slightly and the body height to frame is different side to side. I question whether the frame is square side to side? Anyway, I had the ride height set-up for appearances which makes some of my measurements seem strange as there are referenced to the frame.

    Since four wheel alignment I have only changed the height at the corners.

    To the best of my knowledge, I am the fourth owner of the car. Built as a turnkey in '01 ? and sold to one of Dallas's finest, a Mr. Burnside. It was then sold to a Delta pilot whom did not drive it and then to the guy I bought it from whom only drove it 500 miles. The car had 1500 on the speedo, I have put 1500 on it this spring/summer.

    I will post my data sheet when I get it done.
     
  14. AggieJack

    AggieJack Member

    dwj

    You said (I think) that your master cyl are large on front and smaller on rear. Need to reverse that I would think. Larger size cylinder means LESS pressure. You want greater pressure to front brakes and get that with smaller MC.

    Also, when we had the LS Roundup here in May, three of us tracked our cars at Texas World Speedway. It was HOT- above 90. My tires are Khumo Victor Racers V700, same size as yours. My starting pressure for the day was 20 psi - got up to 27-28 with heat and running. They stuck well. I did bring the rear end around a couple of times under acceleration. (Nobody saw me leave the track- Nobody has pictures of me leaving the track - Nobody can PROVE I left the track!! :wink: :p ) But start with lower pressure.

    You're right about the axle vent puking. I have a breatehr on the axle - that track day I lost over a quart. Started whining the next day was first clue. Putting recirc catch can under there now. Will post pics in couple of weeks when I have time.

    Have fun.

    Jack
     
  15. Roush #1

    Roush #1 Member

    Jack,

    Although I was the closest to you that day, I didn't see you leave the track, but I did see you get back on :lol:

    The only reason I saw you is I knew where to look because I had been off at that same spot before and knew where to look :wink:

    Jody
     
  16. This is a damn good thread!

    I put a Kirkey 10 deg. layback intermediate seat in my drivers position replacing the standard low back bucket. A really good move for me.

    THey are inexpensive ( $200 with everything) , easy to install or take out, lower your C.G. substantially, and really provide great lateral support. I really like it.

    They are not well suited for long cruises on public roads though. But the easy out option comes into play at this point.
     
  17. This is a damn good thread!

    I put a Kirkey 10 deg. layback intermediate seat in my drivers position replacing the standard low back bucket. A really good move for me.

    THey are inexpensive ( $200 with everything) , easy to install or take out, lower your C.G. substantially, and really provide great lateral support. I really like it.

    They are not well suited for long cruises on public roads though. But the easy out option comes into play at this point.
     
  18. dwj

    dwj Member

    All,
    Attached is a pdf of hopefully all the dimensions needed to make my car really tight. My front and back masters are backwards, I will get a 5/8 for the front and leave the back as is.

    I got my springs tested(on the pdf sheet) and also sat in race seat that I think would help me. ($235). Did not buy it yet, want to drive my car over there and pull the standard out and see how it might fit.

    Spent all day yesterday and today making numerous changes and clean up on the car. I will get it weighed again and this will be my new starting point.

    Driving it on the strret today, it appears looser but I still have good straight line grip and with the new front springs, rides a lot better. The track is of course a different ball game.

    Also bought a pyrometer with tire probe and will log tire temps and pressure next time at the track. Unfortuneately, I did not marry rich so I still have to go to work.

    Some of the dimensions on the sheet may seem strange, to me also.
    Let me know if anything is interesting good or bad.

    BP. Why would anyone in MN want to go to an area that is 115 degrees.?
    Get that green monster up here, by the time you get here I may have a clue of what I am doing on the track.

    David

    Attached files lsc_set-up_info_106.pdf (61.7 KB)
     
  19. BPWilliams

    BPWilliams Member

    David,

    I see that you had the car 4 corner weighed and what do you know it is just like mine! 48% front and 52% rear, Big block huh?

    All I can say is that it took me 3 years to get my car to handle to the point that it was fast. This is a very important time for both your car and you as trial and error with your suspension set-up(s) is going to collide with your driving style.

    I do not know how much track time you have but these cars are straight line cars and that means two important factors.

    1) Corner exit speed... These cars turn like Poo, nothing bad, just the basic design of a short narrow wheel base, with high HP. Slow in = Fast out

    2) Braking capability... As corner exit speed increases, straight line speed increases, which means that pre corner braking requirements increase.

    I do not care how good you are at driving, if you cook the corner entry SOMETHING has to give... Maybe the car pushes, maybe the apex gets pushed, maybe the corner exit speed decreases... but something will give.

    As your skill increases and the car's handling gets better all of the before mentioned things can increase or decrease (Decreaseing braking zone, as example) but that does take seat time. I would think that just by trying some of the items listed above and slowing down on the corner entry and getting on the gas quicker your Cobra will get Free'd up....

    Attached files [​IMG]
     
  20. dwj

    dwj Member

    BP,
    Only twice to the track and I am probably diving in the corners too fast or too soon or too low. Ever made a corner have two apex's? Not that the instuctor that dorve the car knows Cobras, but he thought it was too tight.

    Changes are made ,good or bad and I need to log them before I go to the track again.

    As you did, I need to learn what the car is really capable of and mate that with my driving style.

    I will log lap times next time as well as I think what feels fast is not.

    Need more seat time which is tough to do with family and work.

    DWJ
     
  21. David,

    Now you are cooking with gas! Great plan of attack.

    Last year on my last track day I really needed to slow down and work on my smoothness. I forced myself to slow down and not give into the temptation to hammer the gas. I was passed by a Subaru Forester several times. Ouch!

    One guy even said to me that he thought Cobras were faster then mine appeared to be.

    In reviewing my in-car video my driving skills greatly improved that day even though my lap times were just short of embarrassing.
     
  22. BPWilliams

    BPWilliams Member

    David,
    I was not trying to say anything except have fun and be safe. I am fortunate that I got an opportunity to get to the point with my driving that I became an instructor for NASA. We are required to take classes to improve our skills and also our students skills. Some times I go into lecture mode and that was not what I intended to do.

    Trust me I have made plenty of mistakes and I had the mind set of safety first, save the car at all cost second. Save the car won out and that is why I do not race her any more and went to a full track car.

    What is funny is that it is just like Pete said, when I started I was getting blasted by Minicoopers! Nothing like going to the drivers download meeting and a 4 banger complaining that this 'Green Cobra was in my way, and he needs to point me by" But justice is served in the end.... :twisted:

    You will be surprised if you make changes, good or bad and go to one event a month during your season, your skills will improve greatly. I really think the two day events are the best so try to swing a two day one some time. I go on Saturday run the car and play with the tire pressure, then go home and make any serious mods, then back on Sunday to check the results. Two days of driving will kick your butt, but it is worth it.

    You have a great plan, take good notes, and most of all have fun! That is what this is all about right?

    PS Yes, I have even went through a corner backwards, it was not very fast, but the WOW factor was right up there! (Arizona Motorsports Park, turn 5 going onto the back straight, spun at 80mph through the turn and off the track)
     
  23. dwj

    dwj Member

    BP,
    Did not feel like you were lecturing, all good feedback. In general, I do not have a lot of patience and will surge ahead instead of "analyze until paralyze". Hopefully not recklessly.

    This is one of the reasons I bought an LSC all ready built, although I have changed enough and spent enough time on it I consider it my car. I wanted to drive, not try and fit a body on the frame. (Maybe after I learn about this bad boy I will do a build?)

    One of my daughters is heading in the direction of getting serious with horses. I may need to start dumping money into 1 or 2 HP instead of 500+.
    I know even less about horses other than they bite and kick.

    I completely agree with you on time between track visits, I would like a couple of hours/day for four days straight.

    Good luck with new car with the distributor in the wrong place.

    David
     
  24. dwj

    dwj Member

    Finally made it back to the track today only to complete 5 laps before the rain came. Three significant changes since the last time.

    1. I put in a Kirkey series 47 seat. I love it, you do not flop around like the standard LSC bucket. I bolted it to the pan minus some bearing plates. I sit about 2 inches lower and what a difference that makes in the feel of the car.
    2. Lighter springs in the front, 310 from 400. I am probably too light as I had the shocks at 12 out of 16 and almost bottomed them out. Nice on the street, though
    3. Panhard in upper hole on frame side versus lower. This angles the bar slighlty up from horizontal toward the frame.

    I also tried very hard to go in slow and accelerate sooner and harder. Although I only got in two warm-up laps and three "hot laps", I enjoyed the car and the reactions much better than the prior trip. I am no longer too tight in fact my guess is if I could have ran the whole day I would have moved the panhard back.

    There is only one more track day this year and I have to be out of town for work. Always next year.
    DWJ
     
  25. fasteddie

    fasteddie Member

    How did the kirkey seats fit and do you have a picture of them installed?

    Thanks!
    Ed
     
  26. fasteddie

    fasteddie Member

    How did the kirkey seats fit and do you have a picture of them installed?

    Thanks!
    Ed
     
  27. dwj

    dwj Member

    Fast Eddie (FE),
    Only put in a drivers. Have not decided whether to do the passengers( only have one roll bar so I am pretty mellow with a passenger in the car). I might use the standard LSC for driving around on the street.?. The cover color selection is not that great, I picked what I thought would go best with grey interior. Not sure if I like it from an visual. Few comments and watch outs.

    I used wood temporarily for the supports under the seat, the rear of the seat has 2.25" thick "bars" and the front .75". I like the seat to stand up straight. As I like where I have it, I will get aluminum, UHMW or Delrin spacer/bearing blocks, depending on what I can find in some boneyards.

    I used the same back two holes in the floor pan that the standard seat uses and drilled two new front holes. It is a challenge to get the seat where you want it before you start drilling holes in the seat and the floor. I set in it with the harness on and then had my wife hold it while I got out.

    As your thighs are locked in so to speak, the angle to the pedals left and right is important. Kirkey does make side mount supports but I did not want to turn the floor pan into swiss cheese.

    Make sure you try out seats somewhere so you know what width to buy. I am small and used 15". (My wife can actually fit in it)

    I may put two additional mounts on the back of the seat by the shoulder harness mount this winter?

    Watch outs.
    The cover does not completely cover everything, you can see the aluminum seat from the back and around the back bottom inside the car. This seat is for go not show.

    The left shoulder support as I have positioned my seat is very close to hitting the door.

    You may need to move your lap belt fastening position on the frame to better align with the holes in the seat that it threads through. I will move mine this winter.

    These seat are a lot hotter than the standard seat as your thighs, ass and some of your torso are contained.

    Hope this helps.

    Attached files [​IMG] [​IMG] [​IMG] [​IMG]
     

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