PBR Allstar's dirt oval thread! UPDATE!

[SteveK]

It's nice to have a place for dirt oval stuff.

My question is: I just picked up a Dual Sport and I was thinking about making it a dirt oval car, What class would it convert to the best? They run bombers and Sprint cars mostly right now, they're trying to get a latemodel class going but I don't want to have the only one out there. Bombers they want your car to be truck based and they limit the tires to street tires, I'm not real keen on that class cause they are always really loose. How would it do as a sprint car?

The DS is a bit narrow for dirt ovals, if you are trying to run against regular-width cars. There was a spec class for them at my LHS years ago, but it died out within a year like pretty much every spec class they ever tried (Legends, parking long racing, etc. I expect the Losi sprinters and late models to be dead soon too). Guys also tried making 'staggered' cars with RC10 buggy arms on the right and DS arms on the left, but nobody ever really stuck with it. For the heck of it I actually built a rolling chassis with DS arms on the left and RC10T arms on the right, with a mid-mounted motor on a graphite chassis, but I never got it running.

What bodies would they run in the 'bomber' class?

chassis with DS arms on the left and RC10T arms on the right with off set battery is a car i always wanted to make!!! any pics of this?? if not what front end did you use?? i was thinking buggy or maybe ds..do the ds arms fit on buggy front end without mods or do you have to trim the mount???

No pictures of the original, it was around 1999 and I didn't have a digital camera at the time. I still have all the parts to do it again in my workshop. I think I used a stock DS front end a 10T arm on the right side, and it was mounted to the aluminum chassis. The stock DS shock tower had a piece of an old Kyosho tower I got in the clearance bin bolted on to it for mounting the shocks. The rear was the regular DS shock tower. It was almost a completely bolt-together chassis, I maybe had to drill a few holes for mounting things, and I know I had to grind down the bumper mounts on the DS front plate to clear the 10T arms (I used that front end for a truck with the Factory Works dirt oval shock towers at some point too).

[PBR Allstar]

Haven't been posting much here, but I've still been running the sportsman mods. And winning with them against B3's and B4's just thought I'd share a little setup for the other oval junkies out there!

track is 100' driveline, very high bite adobe clay, on custom works rubber tires.

TC3 threaded shocks with .71 shafts front and rear with RPM long spring buckets
stock front tower, slightly shortened rear tower
.125" rear wheel spacers L&R
0 degree rear toe
1mm front toe out
High downforce EDM body

RF:
7lb spring
60 wt oil #2 piston
20 degree blocks

LF:
5lb spring
30 wt oil #2 piston
20 degree block

RR:
8lb spring
50 wt oil #2 piston

LR:
8lb spring
35 wt oil #2 piston

[jsrracing]

i race at the same track as mark .

I am currently waiting on a conversion for my rc10 to a sprint .


I went to the track for some test and tune with the buggy as a buggy .

when i ran it was very fast during pratice with the sprints .


drove it wot with the wheel locked left and used the throdle to turn. (like a plow)

what set up will let me carry my stright away speed through the corner.

the buggy is set up like a buggy 3degree toe , green springs, 40rear/30 front 1oz center nose.

the conversion is a mid motor conversion. motor limit will be a 13.5 and buggy tires .
I have a direct drive trans and a stelth which will work better?

[PBR Allstar]

If it's the track mark posted the video link of I think the first thing I would be doing is taking the 3 degree rear a arm mounts out and putting in some zero's, with zero degree rear hub carriers as well. that will help get the car to rotate in the corner. As far as being able to carrry straight away speed in the corners, I don't know on a paperclip track like that, those corners are pretty tight for how long the straights are. Also for a track that smooth you're going to need more spring. I would get a selection of springs from about 4 lb's to 8 lb's. and start with something around a 6 or 7 pound spring on the rear of the car, with even oil. in the front start with a light spring on the LF with light oil, and something about 30 percent more in oil and spring rate on the RF. You could also try some caster split in the front, 15 on the LF and 20 on the RF.

Hope that helps!
ford cook

[Charlie don't surf]

You may also want to play with the bumpsteer I mentioned in another post, most paperclips like bump out-

[SteveK]

i race at the same track as mark .
I am currently waiting on a conversion for my rc10 to a sprint .
I went to the track for some test and tune with the buggy as a buggy .
when i ran it was very fast during pratice with the sprints .
drove it wot with the wheel locked left and used the throdle to turn. (like a plow)
what set up will let me carry my stright away speed through the corner.
the buggy is set up like a buggy 3degree toe , green springs, 40rear/30 front 1oz center nose.
the conversion is a mid motor conversion. motor limit will be a 13.5 and buggy tires .
I have a direct drive trans and a stelth which will work better?

A rear-motor car with a buggy wheelbase will likely be easier to drive. The Kranzel Terminator conversion kit is mid-motor and works great, but it really stretches the wheelbase which makes it more stable. If you keep the short wheelbase is will have a lot of steering response, so you'll have to stay on your toes to keep from getting twitchy and spinning.

Direct-drive has faster throttle response and less rotating mass, the Stealth will probably feel smoother so I would start with that. Get the car drivable with the Stealth first and then experiment with the other transmission.

On thing I love about oval racing; you can just change stuff on one corner and not worry about the other three LOL It's actually very liberating for somebody who checks and rechecks ride height and camber. Oval is also the only place I would run threaded shocks, so I won't go nuts trying to match the preload on each side.

[Bent]

PBR sorry it took so long to get back to you things got a lil busy here. Im sorry to hear that you trashed a new car and was injured. I hope you get well soon. I finally got to take the modified out and it did pretty good it pushed just a bit in the turns but I know why (the esc location) Other than that it did great.

[markt311]

OK, I got the dirt oval bug, I rebuilt my racer RC10 and I'm building a sprint car with my left over parts.

I'm going to cut a chassis out of G10 and use my DS nose plate since it has less kickup than a buggy piece. Any suggestions? mid motor? It will probably use a DS rear shock tower and pretty much stock suspension front and rear. Hopefully I can have it done within 2 or 3 weeks.

Does any one know a good source for a cage and body?

[PBR Allstar]

dynotech has about the cheapest deal going on cage and body parts. they are also interchangeable with the customworks stuff as far as the mounting holes go.

[Bent]

PBR Thanks for that link I have been searching all over the place for them side wings. and here is the whole kit for 18.00. Thanks man


For thoes who dont have the exact adress to the site here it is

http://dynotech-racing.com/

[Charlie don't surf]

DS nose plate

The DS plate is like 4-7 deg k/u, she won't turn at all. Most production DO cars are anywhere from 15deg, to 25deg currently. You need the K/U angle to give your car the front weight transition, while still maintaining froward drive. If you can just start with a car just like PBR's
then make small changes, caster split/springs/oil etc. You'll have alot more fun

[PBR Allstar]

+1 on the DS noseplate. I forgot to mention that earlier. you need the kickup angle. Like CDS said, most D.O. cars have that kick up built into the front suspension mounts even though the chassis plate is flat (some D.O. cars do use a traditional kickup still). I'm not going to repeat to what CDS said, but I will add that with a DS front kickup you wont get a lot of caster out of the car. On all my D.O. cars, RC10 based and purpose built I never find myself running less than 15 degrees of caster, with the D.S. nose plate and 30 degree blocks your caster angle will only be like 10 degrees. The car will want to trip on it's nose and will not transfer weight like it needs to. This is one thing people over look and think "I'm gonna run low caster angle so I'm not tipping the tire on edge" when in reality tipping the tires up on edge is a big tuning tool as far as weight transfer goes. when you have caster in the car, and you turn the wheels say to the left you are going to load the LF tire and unload the LR tire (taking cross out of the car) and load the RR which will make the car want to rotate in the corner. Likewise, if you're loose in the corner and you put opposite lock in the car by turning right you are going to load the RF tire and unload the RR tire (adding cross to the car) which will tighten it up. There is a balance to this, and in general I would rather run a car with too much caster than not enough. Not enough caster and the car will be nervous, and unpredictable, and when you get it out of shape it's going to be very unforgiving. I've always found it easier to deal with a car that pushes a bit than a car that spins out every turn. There are a couple other things in the front that will change some of these things, like if you have long axles, camber angles, and bump steer.

[markt311]

Well, that's good to know, at least I didn't waste my time building something that wouldn't work.

They don't run EDM's around here, it's all sprints and minis.

maybe if I build an EDM like PBR they'll let me run with the sprints just for fun

[Charlie don't surf]

I have a CC chassis and Bulletproof cage and wing you can use, then all you have to do is mount the accessories, or---I have lots of carbon with a 20deg K/U that you can make your own chassis out of ( for a sprint)

[PBR Allstar]

Alternatively, you can build a chassis plate out of G-10, drill the holes for a noesplate, and use the stock kickup.