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Author Topic:   New driver and new car
Dirt Freak

Total posts: 402
posted July 23, 2004 09:32 PM  
I'm brand new to racing mods even though I have enjoyed spectating for 20 years. I currently have last years track champion ship car that is bent in the right front upwards but repiared by a friend who has never raced a mod but is a heck of a fabricator. Were looking to have fun and enjoy the experiance with hopes of moving up to a traveling series in ten years. Please bear with me if I use the wrong terms or lingo.

On our first night of racing the car felt terrible loose(chased the rear all the way down the straight) on exit but slightly tight on entry(couldn't get car to bring the rear around without standing on brakes). Watching everyone else, their car seems to come around on it's own with no help from the brakes. Now I'm not agianst driver error by any means but what should I be doing to get the rear to slide earlier so I can stand on the gas to keep the rear from passing the front? I'm not real keen on moving bars and shocks adn things or major chassis adjustment's untill I get a feel for what it's supposed to feel like so I would like to stick to driving style and function. Should I turn harder into the corner or use more rear brake to break the tires loose? The car felt a lot better later in the night when it was tacky and took some rubber. I think I need to increase cross to 52% from my current 46%. How much change does one turn of the jack screw adjust cross? I know it's all about spring rate and preload but what's a estimate based on other car's? I want to compare my notes to others.

I don't have scales yet, just a cantorlever I designed so I could us a bathroom scale to help with set up. I know it's not the most acurrate way but I do what I can for the year remainder) My precentages show, Left 55%, Rear 53% and cross at 44%. I'm just begining to understand cross and how it affect's the car but if someone could dumb it down I could just get it. Not to much though, I am a Mechanical Engineer by trade.

Thanks to all who respond.

unregistered Total posts: 402
posted July 23, 2004 11:45 PM           send a private message to leapinlizard   Edit/Delete Message   Reply w/QuoteBBBBBB
Well leapin, we'll try to take it easy on you since you're just an engineer. (LOL) You are correct about needing to change your cross %. 44% is way too low. You would be better off going up 52% like you said, however The main thing to watch with cross is actually rear split. You want to shoot for 80 to 100 lbs heavier on the LR than the RR. You may also want to add rear % to the car. Shoot for around 58% to 60%. The rear % will help the car to rotate, as well as plant it under power. Having said all that, the first thing I think you need to check is if the rear end is in the car square. That could be causing the squirly ride on the straights.
Odds are that the other drivers are using their brakes into the corner, they may just be doing it smooth enough that you arn't seeing it. If it's not comming around for you, you should dial more rear brake into it. I do agree with you that you need to worry about getting comfortable with the car before getting too deep into making changes. I ran half a season with my base setup before I even started playing with air pressures, but the numbers you posted are pretty far off to make learning to drive the car difficult. Try to get the %'s a little closer, be sure the rear is square, and you might want to ask a veteran driver to look over you car to see if he (or she)(PC) can see anything out of the ordinary. Good luck!

Dirt Newbie

Total posts: 4
posted July 24, 2004 02:08 AM  
Another thing to check along with the rearend being square is the toe out of the front tires.

Dirt Forum Champ
Total posts: 1875
posted July 24, 2004 08:29 AM  
check your pm's

Dirt Freak

Total posts: 402
posted July 24, 2004 01:17 PM  
I don't want to change basic set up either unless I can garentee the change is for the better and I will expect the change to do.

Sounds like everyone agree's to up the precentage and I'll see about adding lead somewhere. We run a 24 gallons of fuel just to get rear percentage and make weight. Without the driver we get 2370 on a 2600 rule. Thanks to all

Dirt Freak

Total posts: 233
posted July 25, 2004 08:09 PM  
I run an old 3 link with 52%cross, 53%left and 56%rear. I have my rear split at about 130 lbs., without me in the car (the left rear has 130 lbs. more than the right rear). When the track is tacky, I have my brake adjuster all the way to the rear, and when it is very dry slick, I go not more than 2 turns back towards the front. When I get to the corner, I hit the brakes for maybe a second to get the rear to come around a little, then I ride the throttle to control the rear end. Hope some of this helps.

Dirt Freak

Total posts: 402
posted July 27, 2004 08:48 PM  
Thanks for all the tips. Really I appreciate the help.

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