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Thread: #210 - Packing for Tracking

  1. #1
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    Default #210 - Packing for Tracking

    Life is rough! I've taken the advice of S.J., and for the second consecutive week I'm taking the day off from work and hitting the track for round two. This time, I'm somewhat better prepared.

    Hoping for less sand and wind this time!

    I've increased the air pressure in the "ragged rubber" to 22 front/32 rear as my cold starting temp. I'll let the temps drift up as I drive and see how the grip feels. I was not able to obtain a pyrometer in the week since my last track day. However I was able to obtain this nifty little pump that sits nicely behind the driver's seat (picture below). It's truly amazing how much stuff you can fit into the car for a track day! My helmet is on the ledge behind my seat. I have a very high-end, high-tech, hi-dollar timing system mounted discretely in the cabin. Do you see it? Amazing, huh!

    I still haven't gotten my HANS or my 6 point harness, but I have been doing some special yoga exercises for my neck muscles, that in scientific studies have been demonstrated to dramatically enhance ones sense of being at pease and "centered" in the seconds right before you hit the wall at high velocity and destroy your neck.

    This time around I'll be running a 50/50 combination of 91 octane pump gas and VP C-12 108 octane race gas.

    I'll report back tomorrow night...right after I order my Toyo Proxes R888s. I've included a picture of the left rear tire. It's in much better shape than the right. The track is predominantly left hand turns, so I suppose this differential tire wear is to be expected.
    Last edited by Dave; 05-07-2008 at 10:43 PM.
    Dave
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    Quote Originally Posted by Dave View Post
    This time around I'll be running a 50/50 combination of 91 octane pump gas and VP C-12 108 octane race gas.
    I believe the Noble uses an adaptive mapping that may be thrown off by a big change in the fuel octane. Of course I am not sure if your setup still uses the adaptive mapping. You may want to reset the maps with engine software after switching the fuels.

    The VP C-12 108 octane race gas is leaded. I doubt your setup stilll has catalytic converters, but for the other owners that still have catalytic converters this could cause problems. Leaded gasoline contaminates the catalyst used inside a catalytic converter, destroying its usefulness and leading to a clogged converter.

    http://www.vpracingfuels.com/vp_01_fuels.html
    http://auto.howstuffworks.com/question482.htm

    Anyways sounds like you have a fun time ahead of you, I am jealous.
    Last edited by cutaway; 05-08-2008 at 05:09 AM.

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    Hopefully you will fill the blue gas can near the track. I always take a 5 gallon jug to remote tracks and fill it, and my tank, at the closest gas station to the track. Take out the passenger seat and be amazed at how much more you can haul-it will be a regular SUV. Nice to see someone enjoying their car.

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    Quote Originally Posted by cutaway View Post
    I believe the Noble uses an adaptive mapping that may be thrown off by a big change in the fuel octane. Of course I am not sure if your setup still uses the adaptive mapping. You may want to reset the maps with engine software after switching the fuels.

    The VP C-12 108 octane race gas is leaded. I doubt your setup stilll has catalytic converters, but for the other owners that still have catalytic converters this could cause problems. Leaded gasoline contaminates the catalyst used inside a catalytic converter, destroying its usefulness and leading to a clogged converter.

    http://www.vpracingfuels.com/vp_01_fuels.html
    http://auto.howstuffworks.com/question482.htm

    Anyways sounds like you have a fun time ahead of you, I am jealous.
    As there are no knock sensors in the Noble's engine management system, changing Octane to a higher rating will have no effect other than to reduce the possibility of detonation.

    As the car probably has no problem with knock or pinging at this time, the added octane would be useless. THERE IS NO POWER GAIN AVAILABLE WITH RACE GAS AND THE NOBLE'S CURRENT ENGINE MANAGEMENT SCHEME.

    Also, the lead is not helping anything. Sticking to an unleaded race gas will give the same protection, but without the down side of lead. Lead will occlude your cats if they are still installed, which saps HP. It also shortens the life of the spark plugs. GO WITH UNLEADED RACE GAS IF YOU WANT TO RUN RACE GAS.

    TIRES:

    START YOUR COLD TIRE PRESSURES AT 19 FRONT, 29 REAR. If you want, try 20 front and 30 rear if that is easier to remember.

    From my own experience, starting at 22 in front and 32 rear may induce some under steer and instability. Seriously, NO MORE THAN 20 FRONT AND 30 REAR.

    The car is very light, especially in front. Too much tire pressure, even a couple of lbs can cause the front end to lose grip. In most cases, a drop of 1 or 2 psi is the norm. It depends on the accuracy of the gauge, your driving style, and the particular tire that you are using.

    Same goes for the rear.

    The cars were developed on a race track. The tire pressures were no accident.

    THESE RECOMMENDED PRESSURES WORK! No more is needed until you can quantify your temps with a pyrometer and make the appropriate adjustments if you need to.



    Borrow a pyrometer, and bring the owner to take the temps for you and WRITE THEM DOWN SO THAT YOU CAN SEE WHAT THE TEMP WAS AT EACH OF THE THREE STATIONS ON EACH TIRE.

    With that information, you can get the right pressure in that heavily loaded right rear tire.
    Last edited by S.J.Morgan; 05-08-2008 at 03:24 PM.

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    Smell the high octane VP race gas. It has some nasty additives. There is evidence that this high octance stuff can affect the fuel lines, filters, etc in a car with normal street components.

    I saw a race car the other day with a fuel filter that was eaten by 104 race gas.

    I agree with SJ. Not much to be gained with fancy fuel.
    Dino

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    Quote Originally Posted by turnbaugh View Post
    Smell the high octane VP race gas. It has some nasty additives. There is evidence that this high octance stuff can affect the fuel lines, filters, etc in a car with normal street components.

    I saw a race car the other day with a fuel filter that was eaten by 104 race gas.

    I agree with SJ. Not much to be gained with fancy fuel.
    There are different types of VP race gas. Some are specifically formulated for NHRA PRO STOCK.

    I have not heard of any components being destroyed by the usual types of unleaded, but some of the higher octane exotics can cause problems.

    Best to stick to over the counter, 100 octane unleaded race fuel if you need to. Otherwise, the thing runs fine on 91 or 93.

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    "Loose grip"? There you go again SJ-I AM watching you!

    Take pyrometer readings immediately after exiting the track. If the car sits around, things will even out and the readings will be meaningless.

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    Quote Originally Posted by slo-go View Post

    Take pyrometer readings immediately after exiting the track. If the car sits around, things will even out and the readings will be meaningless.
    Better still to take temps just after a hot lap (before any cool-down lapping), and always start with the most heavily loaded tire (RR in your case) and work to the least loaded.
    And even more better still if your crew can take/record the temps while you sit in the car .
    Joel

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    I agree on the 20 front 30 rear, I don't even bother taking my pyrometer anymore. Those pressures cold work perfect on my car. I have never put any fuel other than 93 octane pump gas in my car, it loves it.

    Jake

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    Best way to get accurate tire temps is to come in after about 8 fast laps. No cool down. This should be enough to get sufficient temperature into the tires, and a good pressure increase.

    Bring the car into the hot pit and stop. Your pyrometer tech should be there to begin taking tire pressures right away. Start with the outside rear tire then outside front, inside front, inside rear.

    Temps are to be taken from the outside tread, center tread, inside tread. Write down the data in this order for each tire. Your pyrometer may even come with tire temp sheets that are organized for this purpose.

    You will probably find that using the recommended 20 front, 30 rear cold inflation pressures will give you a difference across the tread of around 15 degrees or less. If that is the case, don't bother to make any changes unless the center is the hot part. If so, drop 2 PSI, do some laps and check it again.

    At the end of the first session, after you have taken the tire temps, check the tire pressures and write that down. DON'T MAKE ANY CHANGES. You may find that the tires don't have the same pressures. This is normal.

    Rather than make this too complex, post the tire temp data here when you get back. Don't get carried away with checking temperatures. You need to drive the car. Don't bother with it anymore after the first session, and don't make any more adjustments.

    Have fun!

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