Well I'm gonna run in my first demo derby May 2nd and wanting to know any tips or tricks

The car is a 198- Olds 98 302 auto.

I've got the car completely stripped, bumper trimmed, gas tank and batt moved, and doors and such wired shut.

I'm plannin on welding the bumpers solid and chaining it to the hood, making my own floor shifter, filling the door full of concrete, and welding the diff

Anyone got any good tips or stories?

 

depending on what your rules say, you should notch the frame rails front and back to that when you get hit it folds UP instead of possibly going down. If it goes down and plows into the ground then you're just a sitting duck. Again, check with your rules to see if you can do any kind of reinforcing around the radiator, that's the weak spot. Once you lose that you're not going to be running for much longer.

Edit: I've never run a demo derby, those are just a couple tips I've picked up by hanging out with those that do.

 

I've never participated in Demo, but I've pitted for street stock. From what I've observed in the Demo's was the winner's were the one's that could launch their rear end's into the loser's radiators.

 

i have done one, but have been mechanic on quite a few crews

weld your spider gears (as you mentioned)
put washers behind the wheel on 2 or 3 of the studs (makes the wheel wobble, grab better in mud)
chains on the hood might be a good idea, but a really long 1 inch thick all thread is a better idea. you can unscrew the nut QUICKLY to get it off in the pits. if you hood bends wrong, you may fight getting the chains off
on a chevy, you can hardwire your selenoid just like how a ford works. (look into this) and mount your seloid near you (then carry pliers or a wire) dont use a switch to start. (they commonly go out when hot)
a closed loop radiator works the best. or if rules allow, put radiator in rear window. when i say closed loop, i mean loop the hose through engine bay and direct connect, no radiator.
do not pull the thermostat, cut the guts out and put it back in. you must slow the water slightly in order to absorb heat.
use used oil, not new. so dont change the oil on it before you go out
tape your u joints with duct tape (the more the better) this lessens the chance of breaking.
build a slip style driveshaft, kinda like a pto shaft driving farm equipment. it will allow it to shorten
fans are bad news...... they cause alot of harm. either ditch it, or get one with a fan clutch
2 batteries and LARGE wiring are best. (remember, its really hard to start a hot car)
if rules allow, run vacum line to cab to shoot with ether
weld engine down with chains that are bolted on to block (trust me, you dont want it doing flips in the engine bay)
floor shifter as stated, make holes big enough to allow tranny to twist quite a bit
double walled tires if you can get away with it
pre-bend trunk and frame if you can, get it to fold up
cut holes in cab floor to allow any spills to drain
put cooler in cab, run tranny cooler into cab, fill with ice
make a good strong cage for gas tank (i had mine strapped down, and the strap broke)

ill think of more

 

electric fuel pump with shut off switch
pipe across dash
pipe from behind drivers seat to top of drivers piller to far side floor
shorty headers turned upside down on a chevy, then rout heat out of hood
if you have an olds motor, you cant flip headers or manifolds. my buddy made his own headers out of plate and pipe (key is getting heat out, heat rises)
keep fuel lines out of cab if possible, but they must be able to take car bending
weld all body panels together. even fenders.
bend fenders out (cut small slits and bend them up, then bolt them, then keep bending them and cutting them) bends are WAY stronger than cutting stuff off.
remove rubber bushings and bolt car frame to car body, put in big plates for washers

anytime you bolt anything, put a plate in to spread out bolt head and nut, this will help keep from it pulling through

 

post your rule book - a lot of stuff is shown already.

BUT, figure on the radiator getting taken out and hence the tranny cooler. most cars DNF cuz they lose a clutch.

since most rules require a hole in the hood over the carb for fire access, but some HUGE tranny coolers up there so they natrually convect and lasce the car with fans you can control..

there is no 302 for an olds, so I assume a 307? flip the exuast manis and run straight pipes thru the hood.

disable all vehicle electronics like the neutral/park starter interlock. get tractor battery cables for the primary and wire a momentary for the start and on/offs for the fans.

ditch the column shifter and just cut a hole in the floor.

and resist the urge to F-R-F-R etc while the wheels are spinning. bust the wrong part - dnf.

most rules dont let you brace the centerlink/ties but if your can, cut large gas pipe in half and weld around the adjuster sleeves - take a side hit and it will usually toe in the car.

 

put something around the valve stem on your tires. like a peice of pipe

 

Heres the link to the rules
Demo Derby Rules

and good catch quad I meant 307, but my Ford heart wants a 302.

 

better get to work with the double tires.. and replace the factory steering from the wheel to the gearbox. stock is junk and they break easily. give it a slide (steel tubing inside bigger steel tubing, then if you bend it it will last)

 

What do you mean by double tires? I was gonna run some LT 235/75 15's with tubes in them full of water most likely, but gonna experiment with homemade foam tires (If you've ever filled a coke bottle full of Great Stuff then put the lid on, you know what kind of pressure it can make).

Can ya'll think of anyway to reinforce the tie rods without completely remaking the wheel? Maybe the duct tape idea as well as mentioned for the U-joints.

 

Water in tires will only make the track more sloppy. The great stuff foam will be a waste. It has a very low density and will never hold up a vehicle, much less put up with the stress of a derby car. Doubling tires is where you put a smaller tire inside the regular tire. The outer tire takes all the abuse while the inner stays inflated. But where I run I can use tow motor or skid steer tires so I dont bother with that. I did this to a few of my cars and it can turn them into a tank (you car might have an aluminum hood, if so, go find a chebbie caprice steel hood and put it on) Bolt the inner structure on your hood and deck lid together with 1/4 20 bolts and washers about every inch. 3/4" long is good enough. Prebend the rear as well. V notch the back section of frame right before the hump (going from bumper towards rear end) jack car up and set up on jack stands on the frame right at the bumper connection. Remove jack , take BFH and pound the quater panel right where it comes down from the roof to the deck lid. Reweld frame back together.

Also visit DDDA - Demolition Derby Drivers Association for more tips on this car. Its set up alot like here into different makes and models

 

when i say double tires i am talking a tire inside a tire. talk to a good tire shop, they can help you. its friggin hard, but you should only need one set of tires

 

Ive been doing demo derbys for 8 years now, I do 1-3 derbys a year.

You dont need foam filled tires or water or anything like that, doubled tires are ok if you can do that, all we run is some good bias-ply 700-15 mud tires, there usually 6-8 ply, we run them with tubes and hardly ever get flats. Weld your bumpers on very good, you need to weld the bumper shocks up so there solid(collapse them in first), never use chains they only get you hung up on other cars. Concrete in the doors is a bad idea! The best thing for driver protection is a some type of cage with a bar or something across the drivers door.


Go to this site for all the help you could ever want or need on building a car. www.wecrash.com go to the forums.


Heres a pic of a car I built a year ago or so, just so you can kinda see how I build mine.

 

Thanks for the link A-rod, I'm really excited (almost schoolgirl giddy) about running in this derby, I don't know of very many 18 year old high schoolers running in a derby.


I've got the car pretty much finished, I need to stuff the shocks but I don't know how exactly, and collapse the rear bumper and weld it, I already did the front bumper, and yes its on good, me and dad burned a good 2 lbs of 6011's and then capped it with a 7018.


The motor is given me trouble tho, it stumbles sometimes when you go from idle to floor board but will get over it pretty good and then runs like a striped ape (it'll break the rearend loose even with it welded together), but if you floor it and then let off the throttle quickly she dies, she'll fire up easy but I'm confused on what could the be source of it's dying when letting off the throttle quickly.

 

Make sure the idle is way up so it doesnt die when you make hits or get hit.

It is a blast driving a derby car, It just takes alot of work getting them built!