B5M/SC5M No Prep Street Outlaw Drag Car

[Basher67]

I'm hoping to spark up some interest in rc drag racing in southern Oregon. This is my first drag car build. It is based on the Team Associated B5M/SC5M platform. For those of you not familiar with this class of car, Its basically a 2wd buggy that is lengthened to have the wheelbase of a short couse truck. This one started out as a B5M and I changed out the chassis and chassis side rails for the SC5M one. After a little help from the dremel and exacto knife, I was able to mount the SC5M body mounts to the B5M shock towers. I fabricated my own wheelie bar and mounts and topped it off with the Jconcepts '66 Nova body. Rolling on Jcon Startec wheels and proline Hoosier drag tires. I plan on doing some test runs this weekend, weather permitting. I'm using a Hobbywing V3.1 esc and a Sky Rc 6.5t motor. As I get the car dialed in and launching straight, I will be ugrading to a 3.5t motor and a higher amp esc. Probably be changing out some plastic gears for some aluminum ones as needed. I got the 4 gear transmission with ball diff in it right now. The ball diff is cranked down. I'm curious to see how it holds. I might try drilling and pinning it, effectively making it a spool. I'll keep you posted of the progress as I start testing and making improvements on my car.

[KidAgain]

Wow man that’s nice I’ll check it out more in depth tonight bud.

[KidAgain]

First thing I want to know is how you made the wheelie bar cause I love it and looks like its gonna work killer.

Second, before you invest in a higher power esc and or battery get yourself a nice CAP PACK to help with the punch and the first 6 feet it will compensate for a weaker battery for a few seconds. Look for RICARDO SENA on facebook for a 2s cap pack 25-30$ worth every penny....................




Third, shock oils what are you running front and rear you don't want much rebound on the rear you need to slow the shock down, for the front you need to figure out a happy medium so the car doesn't oscillate back and forth during a pass every millisecond counts the straighter the car goes the less distance it will travel.

[Basher67]

Thanks. Bigger cap packs is on the list. I run a 4 cap bank on my 17.5 spec buggy and it does make a difference.
Shock setup right now is 1.6 pistons with 40wt in the front and 1.6 pistons with 50wt in the rear with internal travel limiters. I need to install comression limiters to keep the front from being able to touch the ground. I setup the front where, in a wheelie, the front tires still touch the ground. My thinking was to have control of the car in a wheelie launch.
The wheelie bar is a completely fabricated one-off. Larger main tubes are 1/4" x .049 wall aluminum tapped on the ends. I made some studs using all-thread to connect the tubing to the traxxas rod ends. The smaller cross tube is drilled and tapped as well to stiffen up the lateral support. The wheels are just bearings and the axle they ride on is aluminum tube with thin aluminum spacers to keep the bearings and rod ends spaced out where they belong. The upper mounting point is some nylon body mounts attached at the lower mounting hole for the wing brace on the shock tower. For the lower mounting point, I fabbed a piece of aluminum that attaches where the stock buggy rear bumper goes. It's aluminum angle welded to aluminum tube that has tapped ends.
It took me a few hours to build, but it cost me about $16 in materials plus a few pieces I had laying around. In a crash, if I bend a tube, I can replace it in a couple minutes with another $2 tube.
I'm going to make another one using carbon arrow shafts for the tube, which will make it really durable, but I thought the aluminum looked cool.

[KidAgain]

You definitely have the right idea on the front end and I was told the rule of thumb on wheelie bar height is 2 quarters stacked on top of each other which mine is not even close I’m about 1/4”- 1/2” off the pavement I need to correct this.

[Basher67]

At static, my wheelie bar is around 1/2" off the ground. At full rear compression of the suspension, it is about 1/8" off the ground. The reason I chose to use the 4 gear transmission, is the rotation of the motor is supposed to push the rear down at launch. That's the theory anyway.
I charged up a battery and grabbed a little throttle in the driveway last night before dark. You're right, that ball diff is probably not going to work unless I convert it into a spool. Traction sucked, but it was cold and the tires were new with no sauce or compound on them. I basically had a drift car with a wheelie bar.
I'm thinking about ordering some ultra blue for the tires. What have you tried for traction compound? I was curious if wd40 would be a mistake to try.

[KidAgain]

I’ve tried but it never worked prepping the tires then I noticed all the fast guys just clean the tires with mineral spirits for a prepped track.

The no prep guys don’t allow saucing tires at all so try it with and without so you know how the car will react depending on rules.

On my prostock foam car I use Kofford I think it’s spelled like that and that bitch can pop wheelies with the esc punch settings in the middle and up on demand

[limestang]

It looks killer with the body - great work!
- Limestang

[Basher67]

I swapped in a gear diff filled with jb weld. Ball diff was just going to be a headache. It is totally possible to convert a ball diff to a spool, but jb weld in a gear diff was much less work, at least after I cleaned out the old diff fluid. I had some Paragon ground effects in the hobby room, but wasn't sure what it would do to a rubber tire. I tried it, and was surprised. Once it dried completely, which took a few hours, it was not sticky to the touch or have any noticable residue, but the tires seemed much more grippy, at least on the work bench. Curious to see how it does on the asphalt. It was raining here today with more in the forcast for tomorrow, so it will probably be a couple days before I actually get to test it.

[KidAgain]

Any test hits yet bud.

[Basher67]

No. Still waiting for the weather to clear up. Hopefully by Saturday, I'll get to try it out.

[KidAgain]

No. Still waiting for the weather to clear up. Hopefully by Saturday, I'll get to try it out.

Any luck with testing very curious how your setup works bud.

[AustinZ]

I'm inspired by this thread and since the DR10 still isn't out it may be my route to a cool no prep ride

[Basher67]

We've had some good weather for the past couple weeks and I've been able to go to some empty parking lots (not hard to find right now) and do a little testing. The car goes nice and straight but is still traction limited. I have added some weight behind the rear shock tower to help with this until I get a traction compound figured out since I got screwed over by ultra blue. It's getting a little better and more consistent every time. 3 other guys, that I race offroad carpet with, are currently building street eliminator cars right now. Should be a fun summer

[KidAgain]

What happened with Ultra Blue?