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Old 01-27-2006, 09:12 AM   #1
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Default New On Road car....sort of

This is my project I am working on, it is going to be onroad oval, with a 27 turn Green Machine

CLICK ME

Tell me what you think. If you have any idea, just post them.
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Old 01-27-2006, 11:13 AM   #2
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Any ideas?
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Old 01-27-2006, 02:22 PM   #3
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the link wasnt corecort but repost it im instred
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Old 01-27-2006, 02:23 PM   #4
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oh nvm it worked, looks great hope it works well
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Old 01-27-2006, 02:41 PM   #5
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Looks nice, but center of gravity seems to be quite high. I would make the car as low as possible. But always great to se someone try there own thing. Good luck!
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Old 01-27-2006, 08:08 PM   #6
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Thanks!

We were wondering what we should do about weight savings. Anyone have any ideas? We already have the front and rear arms milled out, but we still want to offset the aluminum. We want to run the aluminum for several reasons, so removing them isn't really too much of an option. We were going to outfit the tranny with the Traxxas aluminum Idler and the delrin top gear too. We also have some MIP CVD's to replace the stock sliders that tend to wear out quick. Other hop ups are in the works, but you'll just have to wait and see them for yourselves!
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Old 01-27-2006, 09:30 PM   #7
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if you are after onroad oval you might want to lower the suspension mounts as oval doesn't require that much suspension travel

this is only a suggestion
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Old 01-27-2006, 10:01 PM   #8
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I do not know what class of oval racing you are planning to use this car for...

BUT....

You may want to change the angle of the front lower A-Arms. You can not run more than 6 degrees of either anti-dive or kick up. For competitive racing, you want a few degrees of anti-dive in the RF and the reverse in the LF. This will help the car through the turns. You want the LF to work as hard as possible to carry the car through the turns.

Lower spring rates on the RF and higher on the LF. This will help with the load transfer. Remember that all loads are transfered through the tires to the springs, and to the chassis.

This type of racing develops very high G-Forces (even higher if racing on carpet) and you will need very stiff springs to keep the front end planted and to avoid excessive chassis roll.
For OVAL racing, 1.5 degrees of chassis roll is about the MAX. Consider using anti-roll bars to achieve the right susspension balance. The right balance between the CG, roll center, springs, and A -Arm length are critical.

The way off-road chassis are designed, the front andrear A-arm hinge pins are way too close and this will cause higher chassis roll. If you can spread the rear a-arms further apart the car will handle much better.

I have not seen where the roll centers will be at, but that is critical for oval racing. You also need to remember that the car needs to be very low to the ground and you want to keep the CG as low as possible.

The way the suspenssion is set up (angle of the arms) the car migh squat whil going into a turn and then change drasticaly as you progress through it.

You may want to use smaller shocks, like the TAMIYA. These are GREAT shocks. You will not need more than 0.080" of suspension travel, thus you can save some weight by using smaller shocks. This will also help you with the springs and handling. Long springs like the ones you have on thecar do not work for this type of racing.
Your shock tower needs to be redesigned too. If you go to lower shocks it will help and you can reposition the camber link position. This is very important.
Also, with the existing shocks/tower combination you are using, no oval body will fit.

IMO, the front A-ARMS are too long for oval racing...but you never know...

This might work for you and I wish you the best.

Being that the motor is mounted behind the axles, you will need to work on your weight distribution to keep the rear end from sliding out on you.

I took another lok at the pictures of your project and I noticed that you have excessive front caster. You want to keep the front caster below 6* and it looks like you have 20*+ This will not work for oval racing (even dirt)
Ihave seen over the years many attempts at getting this combination to work, and to be successful you will need to make manychanges and adjustments.

Have you thought of reversing the motor/tranny. The car will track better if you mount the motor in front of the tranny.


BTw, what are you estimating the weigh distribution to be at? F/R and croos weight. This is very important.

What kind of tires do you plan to race with because this is critical in suspension geometry design. Are you going to use foam tires? This create completely different problems due to the tire/weel characteristics.

I am not being critical at all, I am just passing information to you. I do design work for a living as a PE and I do have extensive experience in chassis and suspension geometry design.

GOOD LUCK, I'M glad to see people developing new cars.

I wish you the best and keep us posted on your results.

Last edited by BATT_MAN; 01-27-2006 at 10:33 PM.
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Old 01-27-2006, 10:23 PM   #9
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I remember for many years ago some articles in RCCA about oval racing racing using Asso RC10's which were converted to onroad cars. I know they rebuilded the shocks by putting silicon fuel tube on the shockshaft and putting the shaft back to the shockbody so the tubing was inside to reduce rideheight so the chassis was sitting lower to the ground (for a lower cg). They used shorter springs instead of the standard otherwise there to much pressure and the shocks weren't working as they wanted. They als showed the RC10 rims which were modified to have foam tires. You also have to use 230mm bodies unless you change the lower arms to shorter arms.
Maybe you can contact Airage Inc the publishes to let them find them those articles.
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Old 01-27-2006, 10:49 PM   #10
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Hi,

I also noticed you are using a HIGH PERFORMANCE aluminum bumper. It does look very nice, but have you thought of the implications of using an aluminum bumper. The idea of the bumper is to absorb energy and avoid thetransfer of the impact loads to the chassis. If you want to avoid possible catastrophic chassis cracks you may want to reconsider.

Oval cars travel at high speeds, added with the mass of the car, the small contact area... you will be transfering very high forces into the chassis through the mounting screws. These forces are excessive and will cause problems down the line.

Think of using Kydex and cut a pattern in it to give it some flex and shock absorbing properties.

Just another suggestion.

IK
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Old 01-28-2006, 01:26 PM   #11
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Wow! Thanks for all the attention guys!

I am planning on using some Pro-Line Road Hawg tires mounted on Traxxas Rustler wheels.

Many other racers in the class use the fuel tubing trick, but for our track we prefer to have a bit of uptravel to help absorb the ruts. Shorter shocks are good, but the design would become unstable when you add in some cracks and ruts. What about progressive rate? A lot or a little? It is kind of bumpy, but I've had luck with moderate rebound and a lot of progressive rate. It gets the chassis nice and low, so when it's on power the Bandit (Which has shorter arms) runs with it's bones below level. It isn't so much that it takes a lot away from the rear, but it is enough to get the bulk of the car low to the ground.

We definatly need more than .08" of travel to help absorb the cracks in the concrete track. The track is highly uneven, and some tight touring cars can flip if the sidewall grabs some of these cracks. We like the rubber tire combo with some uptravel to make the truck more stable. They do weight a considerable amount more than the other cars in the class that choose to run foams, but they are a lot less stable in the straights. Do you have any tips pertaining to setup with these tires?

The bumper does look good, but the nuts on the other side of the bulkhead help keep things from stripping. It will send shockwaves through the truck, but I have raced my Bandit for a while without breaking anything attatched to the bumper. In fact, it helps when you catch a pylon and pitch the nose down on landings... because it doesn't grab the concrete and send the truck head over heels.

Seriously, we are really getting some great results from this thread... so keep the advice coming!!!
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Old 01-28-2006, 01:36 PM   #12
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www.ultimatetraxxas.com

that guy has a done a lot of crazy stuff

like the spider conversion e-maxx

witch in its final stage looks nothing like the e-maxx
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Old 01-28-2006, 01:48 PM   #13
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alm. chassis is kewl

and its super durable,

http://www.ultimaterc.com/forums/sho...&threadid=8113

http://www.ultimaterc.com/land/revie...sis/index.html
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Old 01-29-2006, 01:46 PM   #14
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We want to stick with a modified tub though. The Jang is a pretty cool guy, but he went dirt racing with his project. We want to take our Rusty to the oval track. I think I'll keep my XXX-T MFE for that type of racing.
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Old 01-29-2006, 11:35 PM   #15
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I'm from RI, so I assume when your talking about tracks in the New England area your talking about Madness, Excitement, Maximus or Hobby Chamber. As far as I know only madness and maximus run oval. You might want to talk to the guys who run there and see if there is a class suitable for such a project.
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