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  • #16
    Originally posted by DocNrock View Post
    I can't believe I missed this thread!

    As others have said, slower on corner entry. I've done about 20 track days in my GT-R, but have never driven T-hill. Stock, the car will understeer. Here are two things I have done to mine which make the car handle very neutral. One is to use a 285 square setup. You'll get more life out of the front tires and will have less understeer. The rear 285 tires will mount to the OEM front rims with no problem. To dial out what is left of the understeer, get a set of Stillen sways and set them to the middle setting in front and full soft in the rear (along with the 285 square setup). With these two changes, the car is very neutral and corner push is gone.

    Your cold pressures of 29 are pretty much spot on, and when up to temp, you should be seeing about 37 psi, assuming you're using the OEM Dunlops.

    Another thing that I have recently done is put on a KW coilover sleeve kit on the OEM dampers. This gives you the ability to corner balance and lower the car a bit. Mine is dropped about 1 to 1 1/2 cm. This also allows you to get about -2 camber in front and with that I go with -1.8 in the rear. My toe settings are 1.5mm out on each side in the front and 1mm in on each side in the rear. Top Speed built a GT-R for Leh Keen to drive in OLOA on street tires, which he won and broke every GT-R record along the way. They used the new Michelins in 315 square. My sway settings are the same as theirs. They measured the final ride height at 145 mm, measured from the center indent of each corners jack pad to the ground. This is where I started to allow for my springs to settle, but corrected for diameter, I should be at about 135 mm to mimic their suspension geometry, as their tires are about 2 cm larger in diameter than mine. At their final ride height, they were able to get -2.4 degrees of camber in front. Once I get down to a 135 mm height, I should be able to get that, as well. Once at -2.4, then the rear camber will go to -2.2, as they have done. This is final step I have to dialing in my GT-R.

    Here is their build and OLOA thread on NAGTROC: TopSpeed Motorsports - OneLap GT **2011 OneLap CHAMPIONS - NAGTROC - The Nissan GT-R Owners Club

    Good luck!
    Brent, good post !!
    I was wondering where you were.
    S1 Supermiata - 220whp
    13 Tesla, ma: no engine !!
    17 GT350R
    03 Miata Club Sport
    96 NSX
    06 EVO MR
    15 Mini Cooper S
    Beck 550 Spyder

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    • #17
      Originally posted by bellwilliam View Post
      Brent, good post !!
      I was wondering where you were.
      Thanks William. There was no mention of a GT-R in the thread title.

      I forgot to mention that with a 285 square setup and the Stillen sways, you won't have to worry so much about pushing and you can enter the corners hotter. With the rear sways on full soft (which is still 67% stiffer than stock), you'll be able to get the power down out of the corners without power-on oversteer.

      Also, the stock rotors and pads will not be up to extended tracking. The OEM rotors are notorious for cracking where they are cross drilled. If you are going to track the GT-R, consider AP Racing J hook rotors. I got about 18 track days out of the fronts and the rears still have plenty of life left. They are also less expensive than OEM rotors. Regarding pads, consider Carbotech XP10's or Carbone Lorraine RC6E for the front and RC6 for the rear. I've used both, but really like the Carbone Lorraines, which I'm currently running. They last a lot longer than the XP10's and the mu is slightly higher.

      Oh, and 3 mpg? I must not be pushing hard enough, as I get about 4 mpg when tracking. It takes a lot of gas to move that heavy car that fast.
      Last edited by DocNrock; 08-21-2011, 12:07 PM.
      2009 Nissan GT-R -- nicely modded

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      • #18
        3 mpg. That's a gallon a lap at some tracks! 10 laps and then pit stop in a nasa enduro :-D

        Although to be fair a GTR would get classed in unlimited, so you'd be installing a 40 gallon tank and be allowed to fill it with a fuel rig each stop, so it would be more like 40 laps.

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        • #19
          Doc, I appreciate the reply, I was hoping to hear from you.

          I have read the recommendations to run square and sway's in the past, I was actually hoping for more guidance in technique rather than setup. (Which I have gotten, slower in, got it!)

          My front tires look ok, but the front brakes look cooked, rotors are glazed and the pads were crumbling. I've already gone through and changed all four corners to hawk dtc70's and have replaced the front rotors with dba slotted, the rear rotors held up fine so I didn't bother changing them.

          I'll try the oem setup one more time and then begin modding a bit... I'm going to do things a little different, but I get the gist of it, transfer more load (bigger bars) and put more tire on the ground up front in the turns (camber and wider tires). I'm thinking more of a budget setup would be to put some softer, lower springs up front (more load transfer and increased camber) and some shims up front to dial in more caster.

          I'm running oem bridgestones. I'm not sure if I like them, not having tried any other tire on this car, but my initial reaction is WOW, to how heavy the rim and tire setup is, I strained my back getting them on and off the car. It's obvious why the car is so heavy, everything under the car is so beefy, the suspension components look like they belong on a truck.

          3-4mpg, all I can do is laugh/cry about it. This is going to be expensive...

          Don
          Last edited by donutbob; 08-21-2011, 03:23 PM.

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          • #20
            Hey Don, I just started tracking a couple of years ago, and I've never tracked any car other than my GT-R. So, in a sense, I "grew up" tracking within the limits of the GT-R, and modded it as I found weaknesses, like understeer. Power mods were also done, but that's off topic. That said, other than "slower in," I can't offer any more technique suggestions. Once I hit push, I modded to get rid of it.

            Since you've been tracking far longer than I, I'm not going to give you further advice regarding setup. But I would ask one question. Why depart from a proven setup suggestion (TopSpeed's)? I have no clue if what you suggest will work, or not. Perhaps it will. I do know that following TopSpeed's OLOA setup got me closest to dialing in the handling that I was looking for.

            Finally, the OEM Dunlops are a couple of seconds faster per lap than the OEM Bridgstones, for a roughly 2 min lap. That is for the old Dunlops. There are new Dunlops that are said to be better. I have yet to try them.

            I have no experience with the Hawks or the DBA rotors. I know of one guy on NAGROC who runs the Hawk DTC70 pads when tracking. I don't know much about the DBA rotors other than I believe they are relatively new for the GT-R.

            In regards to expensive, wait until you feel the pull for power mods: big MAF intakes, 1000cc injectors, downpipes, midpipe, catback, custom tune...540 awhp, 540 awtq on a Mustang dyno.

            What year is your GT-R?

            Brent
            Last edited by DocNrock; 08-21-2011, 05:24 PM.
            2009 Nissan GT-R -- nicely modded

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            • #21
              Doc,

              This is going to sound pessimistic, because it is, but I feel compelled to answer because you asked. I don't like(trust?) aftermarket parts. I do have a lot of exceptions to this, especially with my miata as there are many proven and tested solutions to issues over long periods of time, but even then I've run into problems with long term aftermarket specialty shop brands.

              I definitely do appreciate the advice and am listening, I'm not a hardcore track guy or racer, I just like to enjoy my cars to the full extent of their design as much as I'm capable of doing.

              I am also opposed to trying to make any more power than the factory designed, if I want something faster, I buy something faster... but again, I'm a hypocrite there as well, since my miata has aftermarket forced induction.

              Ever since I tried the hawk dtc70's I've never bothered trying anything else, it's what I'm used to and its always available. I leave them in all my cars year round, without issue. DBA rotors, simply because they were available locally, and at a reasonable price. I'd love to try the dunlops, but if the rs3's that are rumored to be offered in the correct sizes become available when the time comes, I'll probably do the hankooks.

              Mine is a 2010, JUST broken in, drove it to the track with 1400 miles,

              Don

              Originally posted by DocNrock View Post
              Hey Don, I just started tracking a couple of years ago, and I've never tracked any car other than my GT-R. So, in a sense, I "grew up" tracking within the limits of the GT-R, and modded it as I found weaknesses, like understeer. Power mods were also done, but that's off topic. That said, other than "slower in," I can't offer any more technique suggestions. Once I hit push, I modded to get rid of it.

              Since you've been tracking far longer than I, I'm not going to give you further advice regarding setup. But I would ask one question. Why depart from a proven setup suggestion (TopSpeed's)? I have no clue if what you suggest will work, or not. Perhaps it will. I do know that following TopSpeed's OLOA setup got me closest to dialing in the handling that I was looking for.

              Finally, the OEM Dunlops are a couple of seconds faster per lap than the OEM Bridgstones, for a roughly 2 min lap. That is for the old Dunlops. There are new Dunlops that are said to be better. I have yet to try them.

              I have no experience with the Hawks or the DBA rotors. I know of one guy on NAGROC who runs the Hawk DTC70 pads when tracking. I don't know much about the DBA rotors other than I believe they are relatively new for the GT-R.

              In regards to expensive, wait until you feel the pull for power mods: big MAF intakes, 1000cc injectors, downpipes, midpipe, catback, custom tune...540 awhp, 540 awtq on a Mustang dyno.

              What year is your GT-R?

              Brent

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              • #22
                ^^^No worries, Don. I find it impressive that you want to keep stock power. It will certainly help if you have any warranty claims in the future. However, since it is a small volume car, the aftermarket has been slim with high quality parts. The wheat has separated itself from the schaff, and quality aftermarket parts are available. But if you choose to keep your car stock in the power arena, there is absolutely nothing wrong with this. One thing I might mention, which you probably already know about, is have you considered a quality dyno tune based on the Cobb Access Port? This and a midpipe are probably the biggest bang for the buck you can get. You'll get a nicer exhaust note with the midpipe and it is probably the most cost-effective power upgrade you can do when coupled to a custom dyno tune. But if you want to keep it stock in the power department, more power to you. To be honest, if I had to do it over again, I probably would keep the hardware stock and just have the car tuned. There is plenty of power left on the table that can be tapped with a tune without changing a single part.

                But as you have identified, there are big improvements to be made in the handling department. Understeer is always going to be incorporated into engineering design as for the average street driver, it is safer than neutral or oversteer. The forumula for eliminating that understeer is pretty well established. I know nothing of the RS3's, perhaps they will be better, I don't know. Interestingly, the R888's for the GT-R in 285 front and 315 rear have not been shown to consistently result in improved lap times over the OEM Dunlops. I look forward to your feedback regarding these Hankooks.

                You say you are not hardcore. But with your experience, your driving overall eclipses mine, that is for sure. In the short term, slower in, faster out, as you've already heard multiple times. Let the AWD pull you out of the corner and you'll gain a lot of time on the straight that follows. If you can cure the understeer, then you'll have higher mid corner speeds and be able to pull out even faster.

                Glad to see another driver on here tracking their GT-R. Best wishes to eliminate the pesky push.

                Brent
                2009 Nissan GT-R -- nicely modded

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