Dirt track bomber advice?

[68coronetGLwannabe]

A friend and I have a 76 Cordoba bomber race car. We race on a 3/8 mile dirt track and are new to this. Its first race was last Saturday and he didn't do so well.  He made 3 laps and then slammed the left side of the car into the wall, breaking the trans mount and bending the left lower control arm. We have talked to a few race guys and they told us to remove front and rear sway bars so the car transfer weight better in the corners. Also they said to crank the torsion bars up as tight as they will go and run heavier right side shocks. they are pretty strict on the rules so you cant run staggered tires sizes and everything has to be stock to the car. Anyone have so more advice before we take it out and beat it up again? Thanks

[skip68]

This will be a cool thread because I know we've got alot of racers and ex racers here.  Any pictures of the wall kiss Wade?     
I heard a trick about filling the drivers rear tire to 50 lbs and laying it in the sun all day.  This will make the tire bigger.     More pictures please.   

[chrisII]

Im an asphalt guy, but it looks like the rf is leaned the wrong way..you want a small amount of camber even on a dirt car. Those cars have a TON of rubber in the front. weld plates between the frame and the K member. also make tabs to weld between the upper A arm mount and the top of the frame. they flex there A LOT. what tires do you run? street tires or race tires.  the street radials NEVER change size except for wear. You can tune that car with the torsion bars. if it is loose (wants to spin out) crank the front up, or left down..go the other way if it gets tight.

   You can find a LOT of info on mopar circle track cars here   http://www.moparchat.com/forums/forumdisplay.php?s=3770d4f7aceaa51a058e28899487df73&f=40 

[68coronetGLwannabe]

Im an asphalt guy, but it looks like the rf is leaned the wrong way..you want a small amount of camber even on a dirt car. Those cars have a TON of rubber in the front. weld plates between the frame and the K member. also make tabs to weld between the upper A arm mount and the top of the frame. they flex there A LOT. what tires do you run? street tires or race tires.  the street radials NEVER change size except for wear. You can tune that car with the torsion bars. if it is loose (wants to spin out) crank the front up, or left down..go the other way if it gets tight.

  You can find a LOT of info on mopar circle track cars here   http://www.moparchat.com/forums/forumdisplay.php?s=3770d4f7aceaa51a058e28899487df73&f=40  

Have to run 70 series passenger car tires on the bombers we are running 225 70 15. The r/front is leaning in because he hit the wall and bent the lower control arm, but that is fixed now.

[JB400]

I'm going to like this thread a lot.  First off, how about some pics under the hood?  It'll let everyone see how your car is braced.  How much does your car weigh?  Have you ever had it scaled?  Front to back weight ratio's?  Also, you might want to talk to Firm Feel.  They probably have a shock and spring setup for you.  Plus, you can get one of their steering boxes because all they do is upgrade the stock box.  You say you can't run staggered tires.  Well, actually you can, even if they same numbers on the sides.  Each tire wears differently.  Measure everyone you have.  A tire durometer would help you out too.  Some tires are stickier than others, even in the same batch.  How about telling us what the rules are.  We can come up with ways around some of them.

[HPP]

I heard a trick about filling the drivers rear tire to 50 lbs and laying it in the sun all day.  This will make the tire bigger.   

That only works with bias ply tires.

Yes, on a dirt car you probably want the sway bars off. Body roll generates bite in the dirt. That also means you want to look at the right front tire's orientation during that roll and you may have to crank in some additional negative camber to keep the tread square to the ground during roll.

Suspensoin travel is key too. You don't want to lower the car to a point that you give up suspension movement.

As a '76, you probably have rubber isolated suspension everywhere. If you can, get rid of it.

So, why did he smack the wall?  Pushed, something broke, or what?

[RallyeMike]

I'm imagining that the bomber class says that the suspension has to be totally stock. The rubber isolators may have to stay in place. However, if you take them apart, hollow out the center, and stick a short piece of pipe in there nobody will ever know.  If the rear is isolated, neatly weld some tabs between the plates and throw some mud over it. That will at least put you on a more level playing field with non-isolated suspension cars.

Since you are newbies, observe or ask what others are running for camber and toe and start there.

Keep us updated. The board's not-currently-racing group needs to hear about it 

[chrisII]

I currently have 2 cars. one started life as the same front end as yours. the other is a 70 B body..on the 70 this year i was able to find that the shocks from a full size GM can be made to fit the front by removing the insert from the lower mount.. I think your car uses a shorter shock, but shocks for a Metric may work.  some of your GM racing friends may have some old spares they can sell you cheap. I found out that the carerras are quite hard to change over to fit the mopar due to the way the insert has the rubber molded on to it.

[68coronetGLwannabe]

So, why did he smack the wall?  Pushed, something broke, or what?
[/quote]

We were not even close to having the car set up right to race. I dont think we had anything close to make the car handle any good. We went in kinda blind, but have learned a lot over the last couple weeks. As far as hitting the wall, it was he just could handle it in the corners  and got it up in the wet part of the track and lost it. we have been working on the front end the last few days and found a few problems with loose parts and a few broken ones. We have removed the sway bars, put on new shocks and finally got some descent camber in the right front. He said just driving up and down my dirt road and in the back of my property the front end feels much tighter and not out of control. We also have the torsion bars cranked up as tight as they will go. Next Friday night we will take it out to the track for some practice. You have to be careful on what you try and do that might not be stock because if you place in the top 3 your car goes through an inspection just like every class of car that races there. Thanks for  the advice on the suspension RalleyMike, we will check that stuff out.

[HPP]

I'm imagining that the bomber class says that the suspension has to be totally stock. The rubber isolators may have to stay in place. However, if you take them apart, hollow out the center, and stick a short piece of pipe in there nobody will ever know. 

Probably a true statement.

With the isolated rear suspension, the trick the factory performed to the rear springs oval eye was to insert steel fillers in the voids of the front eye bushings to firm it up. This is part of what was considered the police package.

[RiverRaider]

Hello,
I have raced that style chassis before with both big block and small block power.  The lower arm collapsed then the car hits the wall.  It fails somewhere between the ball joint and shock, usually by the shock.   Even if you can hang on when the lower bends, a lot of flagmen will black flag you for it.  I have been flagged while leading races.  I have a few suggestions but fix the lower arms first as everything else will not matter until that is corrected.  I would not run the sway bar(s) on dirt.  I have welded plates to the inside of the arm to reinforce the area where the shock mounts.  I also cut flat steel plates to cover the length of the bottom of the control arm.  I cut three rounded corner rectangles in the plate and sprayed some under coating on it to make it look stock.  You are in luck as now days AREngineering.com makes plates to weld on or you can look at their site to get an idea of what I am describing and make your own.  Also do this to both sides of the car so they look the same.  Replace the upper and lower bushings, if you use something like energy suspension make sure you get the black ones the red will draw too much attention.   Your upper A's should move up and down freely.  I believe your K member is on bushings that would be something to eliminate down the road.  You can make spacers to replace the bushings.  If you make the spacers slightly smaller than the bushing you can then bore out the rubber and slip it over your spacer and no one will see the change.  Your rear suspension is killing you.  If it has the rubber still between the leafs and the rear end that needs to be removed.  The leafs if stock will need to be replaced they are for a smooth ride and the bushing allow for two much movement, but for now you can grind both sides of the front bushings.  You want to have the leaf spring move freely.  If you have not done it already take the leafs apart and clean and lube them.  This should be done after every race night on dirt.  You could also take out a leaf on the driver side to put more weight on that corner.  It will also soften it and allow more weight transfer.  Even a cleaned up set of old 69 440 b body leafs will make a noticeable difference .You can crank the bar up on the right front a little and back off the left side.  The suspension needs to work so don't be too aggressive either way. If you crank it all the way you will break parts.  Good shocks are the very important and should be checked every race. An easy up on the right front may help.  Measure all your tires as there may be a little size difference ½ to ¾ may be possible.  You can try wider or narrower wheels to gain a little stagger, it will not be much.  Also by replacing the bolts in the front leaf spring mounts you can put spacer plates in to give yourself a little rear steer.  If you do this use reinforcement plates on both sides of the factory mounts.  You can also drill four new holes to set the mount higher therefore lowering that side (drivers).  Do you have scales?  You can send me a private message its easier to discuss on the phone.   Most tech guys won't know what they are looking when it comes to Mopar so if it looks stock they won't bother you until you win then they change the rules.   
RiverRaider           

[68coronetGLwannabe]

Thanks for the Info RiverRaider.  We are slowly working on the things you and the others have suggested.

[68coronetGLwannabe]

I'm going to like this thread a lot.  First off, how about some pics under the hood?  It'll let everyone see how your car is braced.  How much does your car weigh?  Have you ever had it scaled?  Front to back weight ratio's?  Also, you might want to talk to Firm Feel.  They probably have a shock and spring setup for you.  Plus, you can get one of their steering boxes because all they do is upgrade the stock box.  You say you can't run staggered tires.  Well, actually you can, even if they same numbers on the sides.  Each tire wears differently.  Measure everyone you have.  A tire durometer would help you out too.  Some tires are stickier than others, even in the same batch.  How about telling us what the rules are.  We can come up with ways around some of them.

Here's the rules:

2012 Bomber Rules

The purpose of this class is to establish a low cost, entry-level form of dirt track racing. The main object is to have a class of cars that is fun and cars that is inexpensive.

IF IT DOESN'T SAY YOU "CAN" IN THESE RULES, ASSUME YOU CANNOT !!!!!!!!!!!!!

Tech inspector's interpretation of these rules is final!

CAR RULES: All cars must be American-made passenger sedan, hardtops or station wagons, produced within the model years of 1964 through 1987. Cars must remain stock and completely intact with no cutting, gutting, stripping, reinforcing, or modifying, except as specifically outlined in these rules. Camaros, Firebirds, El Caminos, Rancheros, and Mustangs are NOT allowed.

ALL CARS MUST HAVE: All cars MUST have a minimum of a 4 point roll cage with a roll bar and three driver's side door bar minimum. Tubing size of 1 1⁄2 by .120 wall thickness. The Cage and welds must meet Arizona speedway tech inspector's safety standards. Gutting of drivers door is allowed for multiple door bars (3 MINIUM). NO other gutting allowed. NO black pipe. Bars must be mild steel or chrome molly. They must be bent, No 45 degree angle cuts in roll bar. No drilling or cutting of bar. No gutting, reinforcing or modifying except to mount roll cage to frame. Anything that is flammable or could possibly melt smolder etc., on the interior of the car may be removed, dashes are optional. Metal is not one of those items.

Fuel cells are mandatory, (As of march 15th 2012) and must be "COMPLETELY" sealed off from driver's compartment with 22 gauge sheet metal. The fuel cell must be centered on trunk floor and must be strapped with 1 inch wide x 1/8 inch thick flat stock. Must have 2 straps going up and down and one side to side. Flat fender washers are to be used to mount fuel cell to the bottom of trunk floor. 22 gallon fuel cell maximum. Must have a ground strap from filler neck to a chassis ground. Trunk floor must have 2 holes for fire extinguisher access, The holes must be at least 5 inches wide. All stainless, plastic, glass, diecast trim parts, lights, and moldings must be removed from the outside of the car. Door panels must be removed. Driver's door must be chained or welded shut. Rear seat must be removed and resulting holes must be replaced by sheet metal (22gauge maximum thickness).

An aluminum racing seat is mandatory. Must use a 5 point harness seat belt (No more than 5 years old) and must be mounted in a secure way. (Subject to approval of Arizona Raceway officials). Numbers (16" minimum) clearly painted on both sides and on the roof facing the right-hand side of the car. Bumper straps 2" flat stock x 1/8 thick, (no thicker than 1/8 strap may be used) and must be fastened from the ends of the front and rear bumpers to the frame or rear quarter panels. (All Sharp edges must be removed.) Drive shaft must be painted white. A 1inch x 1/8 inch thick driveshaft loop mounted towards the front of the driveshaft is mandatory. Batteries must be securely mounted.

[68coronetGLwannabe]

More rules


ALL CARS CANNOT HAVE: Exposed glass. All glass MUST be removed (windshields, door glass, rear window, head lights, and tail lights.) Mirrors of any kind are not allowed. Fuel injection or turbo chargers not allowed. No modifications or reinforcements of any type. Exception: severe frame damage may be reinforced accordingly. No cattle guard's on front or rear bumpers. Recapped tires, tires without tire size numbers on them, tires with other than regular highway tread, or re-grooved or siped tires are not allowed. No added weight/ ballast at all.

Windshield screen and a 1" inch vertical driver protection bar placed in the middle of the windshield area are mandatory. A radiator mud screen is recommended. Exhaust system may be removed starting at the trans-cross member and back. Exhaust must be a stock "Y" pipe or 2 single "dual" pipes. No "X" or "h" pipes allowed . No aftermarket 2 into 1 exhaust. No RAm Horn exhaust manifolds on Chevrolets , Headliners and carpet must be removed. Front inner fender wells may be removed. Mister systems are allowed. Maximum 5 gallon plastic tank mounted securely to the floor behind the driver's seat and as close to the driver's seat as possible.

TIRE AND WHEELS: Maximum tire size is 235-70R-15". This means no number larger than 235 in the first set of numerals, no number smaller than 70 in the second set of numerals. No LT or snow tires. "P" rated passenger tires only. All four (4) rims must be the same diameter, no offset or reversed rims, steel wheels are permitted, 7" maximum width. Aluminum wheels are not allowed. Recommend 1" lug nuts. Wheel spacers are not allowed.

TRANSMISSION AND REAR END: Transmission must be automatic and be stock with no modifications and mounted with stock cross member. Rear end must be stock and mounted in stock location with the wheel base matching from side to side, 3⁄4 inch tolerance, must have stock trailing arms for make and model being used. An open, locked, or posi-traction rear end will be allowed.

ENGINE: Must be STOCK with stock engine mounts and be in stock location. No solid motor mounts. Must have stock unaltered carburetor and stock unaltered air filter housing. Aftermarket valve covers are ok. Distributor must be stock with stock components. Stock steel engine pulleys are required. Aftermarket aluminum radiators are allowed. No roller rockers or roller cam allowed. No machining grinding or blue printing of valve head and must have stock valve springs. No pop up / dome pistons allowed. Camshaft must pass a vacuum gage test and measure no less the 16 Inches Hg (vacuum) at 1200 rpm maximum. Drivers are responsible for having a 3/16 port in the intake manifold to hook up a vacuum gauge. Chevrolet engines up to 360 cubic inches maximum are allowed but must run an unaltered Rochester 2 barrel carburetor (1 1/16 throttle bore maximum) with a stock unaltered 2 barrel intake only. Aftermarket spacer plates are NOT allowed between carburetor and intake. Stock stroke crankshafts only. No strokers of any kind. All motors must use OEM internal parts. No light weight or knife edge crankshafts, connecting rods must be OEM I-Beam style only.

SUSPENSION: Must remain stock. No spring spacers or spring rubbers allowed. No weight jacks. Must have all 4 brakes in working order. No line blocking or fluid limiting. No racing springs, no Bilstein / QA1 or other racing shocks allowed.

ALL DRIVERS MUST: Have a Snell approved 2000, 2005, or 2010 full face helmet. Helmet Certification tag or tags must be on helmet and visible. A full fire suit, neck brace, and racing gloves are mandatory. A driver side window net is mandatory and must be in good condition.

Winner of previous main event must start last in his or her next main event.

Understand the track running rules and flags. Understand that the race may be stopped at any time and have the field turn around and go clock wise. Know that purposely hitting another car in the driver's door will possibly result in being suspended from this class.

ENGINE PROTEST: Any Bomber driver may protest an engine by posting a $125.00 protest fee to an Arizona Speedway official. Protested engines will be required to have one valve cover, one exhaust manifold, one spark plug, and intake manifold removed to verify rule compliance.

If engine is legal the protested driver will get $100.00 and the track $25.00.

If the engine is not legal or the protest is denied: $100.00 goes back to protester and 25.00 to track or point fund.

If found illegal or protest is denied:

1st time offense: $100 fine and or no points for the race.

2nd time offense: $200 fine and or no points for season.

3rd time offense: Driver suspended for the year and forfeits all points and point fund moneys for the season.

CLAIMING/SWAPPING: Only a car that finished in the main event can be claimed for $1000.00 cash and the claiming driver must swap cars. Cars will be relinquished as raced except for the battery, safety harness, racing seat, steering wheel, and fuel cell. If the car is claimed and the claim is denied, that driver will be DQ'ed for that race, suspended, and fined.

1st time: $300 fine and no points for the race. And a suspension of one week.
2nd time: $500 fine and no points for remainder of the season. And a suspension of two weeks 3rd time: Driver suspended for the year and forfeits all points and point fund moneys.

WHO CAN CLAIM/SWAP: A bomber driver who raced in the same main may be the ONLY person that can claim/swap and it must be done by stopping on the track after the race and notifying a track official of the claim/swap. Must have the $1000.00 cash at that time. If more than one claim on the same car in the same night happens then the highest finishing driver claim takes precedent.

All claim/swaps are final.
Racecievers are mandatory for the 2012 season.

[JB400]

What motor are you running?  318 or 360

I don't see any weight limit.  Nothing on +/- rear leafs. I recommend getting as early of manufactured parts for the motor.  No smog stuff.  What about carb.  Do you have to run Rochester like the chevy guys or can you run Holley  500 cfm?
What about your ignition system?  Are you running lean burn or electronic?  Which ecu, black, orange, or chrome?

I like what River Raider said about the suspension.  Reading other rulebooks, some have camber limits.

As for this part:    IF IT DOESN'T SAY YOU CAN IN THE RULEBOOK, ASSUME YOU CANNOT,   my response is THERE'S NOTHING STOCK ABOUT A STOCKCAR!!!!!

[68coronetGLwannabe]

We are running a 360 with a stock Thermoquad. All smog stuff removed and a electronic Mopar ignition with a blue box.

[Cooter]

We have something similar called the "Anycar class". ALOT of fun I might add. That is until someone slams into your junk.

[Indygenerallee]

OH don't forget the Nitrous injectors under the intake trick  I have seen that done more than a few times, The guy that did it hid the NOS bottle inside a dummy compartment in the steel fuel cell!! and ran the line beside the brake lines up on top of trans and drilled a hole in the galley area on block and ran the line into the injectors under the intake, pretty slick setup.

[68coronetGLwannabe]

Well, we have done a lot of things that were suggested here. We are going to race it tonight and see how it does. Hopefully better than last time. 

[rayderluvr]

Sounds like a lot of fun. Good Luck!

[JB400]

How'd things go last night? 

[68coronetGLwannabe]

Things went much better last night. Car handled much better and we made it through the heat without incident. Got into the Main event and 14 laps of 20 another car cut under him pushing him into the car on the outside of him. Both those cars went of the track and he held onto it, but it bent the steering center link, which now looks like a *U*  and he couldn't steer. so he did one more lap and pulled of the track. All in all it was a much better night and you could tell the car handled much better. Each lap I could see he was feeling much better about the car and he was driving it much faster each lap. They did have a super Mod. that flew over the back straight away guardrail and rolled a few times. From what I was told he lost a few fingers and his car was demolished.

Thanks For all the help everyone has given, it helped us out a lot. 

[JB400]

I'd call that a respectable night.  Too bad he didn't have the finish to back it up, but you guys are headed in the right direction.  How many more races in the season?  Sounds like the mod driver didn't let go of the steering wheel.  I've heard of several drivers taping up the spokes on the wheel to keep stuff like that from happening.  Best of luck next week.

[68coronetGLwannabe]

3 more race left in the season. They pick up again Jan 1st with a Bomber enduro race of 125 laps. If everything goes well we may try that one. I will post up some pics later.

[JB400]

Still plenty of time to try new stuff.  The key to winning the enduro race is to pace yourself.  Too many go all out for it and usually don't finish.