New guy with a few questions. Stock class race Bronco.

[hobbyturnedobsession]

Deavers on a bronco work really well as long as the shock has enough rebound in them.

[Crawlfab]

Deavers on a bronco work really well as long as the shock has enough rebound in them.

I hope so.

I got it cleaned up and pulled in the shop today. Will get some pictures posted up. Deavers showed up also today and picked up a used set of jba headers local for $80

I had a deal going today to buy a set of like new take off 5150 bilsteins but it fell through. So with that adding up the cost of 6 5160s and my dealer cost on Radflo 14x2.5 threaded bodys for the front and 14x2.5 smooth bodys for the rear it was 2 close so im moving classes.

Here is the rules I have to fit now. They are much easier to fit and understand. The reason for the 14" shocks is King of the Hammmers emc stock class allows only a 14" shock and since my deavers showed up today im gonna run the 5.5s in the front get threaded shocks for the future of going coilover in the front.

1.2.2:  Mod Trail Vehicles.   The intent of the Mod Trail Class is to allow racers to modify their vehicles suspension, body, chassis and drive train for added performance, but still retain limits that distinguish the class from an unlimited vehicle.

1.2.2.1: All Mod Trail class vehicles will be required to meet the Dirt Riot minimum safety standard requirements, which include; 4-point harnesses, solid metal hardtop over a 6-point cage that is tied into the frame of the vehicle, solid metal doors or door bars that extend from the b-pillar at shoulder height to the a-pillar at the ankle/knee height, 2 – 2.5pd rated fire extinguishers.

1.2.2.2: Frame: Mod Trail class vehicles must retain the OEM frame from the motor mounts (front mounted motors only) to B-pillar of the cage. Material can be added to the OEM frame.

1.2.2.3: Body: A Mod Trail Class vehicle must retain the cowl (firewall), have a front hood, and front grill. The floor in the passenger area must be complete enough to cover all components, extend from the firewall to behind the seats and to outside of the seats. A rear firewall must separate the passenger compartment from the fuel cell to at least the top of the seats at shoulder height.

1.2.2.4: Drive Train: A Mod Trail class vehicle can modify drive train to any extent as long the modification is automotive based in nature.

1.2.2.5: Suspension: Suspension modifications are unlimited as long as only one shock of any type is used per corner (limit 4 shocks).

1.2.2.6: Tires: A Mod Trail class vehicle is limited to a 37 inch tire by sidewall designation.

1.2.2.7: Steering: No limits established except rear steer prohibited.

1.2.2.8: Fuel cells: After market cells are acceptable, manual shut off valves must be added to all fuel lines and vent lines. The fuel cell filler must be in a location and shrouded in such a manner that fuel cannot be splashed into the passenger compartment during the fueling process. Fuel Cell mounting must use a strap type mounting system.

1.2.2.9: Window nets are highly recommended. 

[Crawlfab]

Ok well since choosing to step up classes I came across a deal on a new set of King 2.5x16 smooth body's for the rear at a good price but I'm torn on the front suspension.

I'm not sure what the best shock setup for the front it. I have it down to 4 options and they are all close in price.

option 1 is cheapest. Use the deaver coils and a set of smooth body 2.5s.

Option 2 is use the deavers and a 3 tube 2.5 bypass.

option 3 is sell the coils and buy a set of 2.5 coilovers.

option 4 is use the deavers and a 3.0 smooth body.


What would you guys choose and why is the question?

[ChaseTruck754]

Coilovers. Adjustablility & ease of changing spring rate per driving style/preference. Cost isn't much over the coils & buckets & smooth body, etc.

Now some of the cost difference may go out the window since you already have the Deaver coils & the smooth bodies, but the adjustability is nice. You just might want to look at a 3.0 coilover vs. the 2.5 due to the weight of the truck & the lenght of time/# of laps you guys run. Not sure a 2.5 might get some shock fade there, but it may.

Either way will be a night & day difference from 5100's though.

[PaulW]

Agree 3" is the way to go. IMO 2.5 ias not the correct size. Like they say bigger is better.
3" still get hot , but will not fade in my experience.

Trail rigs can get away with 2.5s and even 2.0s.
PW

[Crawlfab]

On the 3.0s most seem to be running a single coil? Or is it single coil with a tender? If its a single coil it looks to be about $500 more to go with a 3.0 in the front. That's also the performance series from king.

The smooth body 2.5x16s are gonna go through the floor in the back. Need to get my beams back so can get it weighed. It looks lite. with stripping the interior and ac the rear factory shocks have raised 2.5" Gonna take a long shackle to get the height back down to the 4" lift area. I will probably run 2 spares in the back to get some weight balance.

[Crawlfab]

Well had planned on running shocks that I am a dealer for all the way around but just pulled the trigger on some new 14x3" swayaways for the front. Now just gotta figure out the spring rates on the 3" stuff.

So now I have my 4.88 gears here.
deaver j40s
16x2.5 smooth body kings for the rear
14x3 threaded swayaways
beams are are getting cut and turn
rcv ttb shafts ordered


Get a few more parts here I will start a thread in race builds. Hope its gonna be as fast as its looking like it can be.

[cs_drums]

If you plan to run in 4wd the whole time and you want to save time and money on electric - manual t-case swap. Checl out the shiftster.

[Crawlfab]

If you plan to run in 4wd the whole time and you want to save time and money on electric - manual t-case swap. Checl out the shiftster.

Working on getting a manual 1356 at the moment as there are spots where will need 4low but only for maybe 30 seconds then back to 4 high.

[Wrightracing.net]

Just wondering why you went with 488 gears? On a race only rig you would get much more power to the ground running 5.14 or 5.29 gears. You most likely will not run at highway speeds and would greatly benefit from the power to the ground. From the charts I have looked at you could run 5.29 gears and still be good at 60 mph with the rpm's. Even in Baja they average 40 some mph.

[Crawlfab]

Just wondering why you went with 488 gears? On a race only rig you would get much more power to the ground running 5.14 or 5.29 gears. You most likely will not run at highway speeds and would greatly benefit from the power to the ground. From the charts I have looked at you could run 5.29 gears and still be good at 60 mph with the rpm's. Even in Baja they average 40 some mph.

It was a trade off. I figure they are low enuff to run most of the time in high range without loosing to much ring gear strength. If the course is short and tight I will run low a lot of the time.

[Wrightracing.net]

In our 500-800hp baja trucks the ring gears do just fine running 5.14 & 5.29. That is running 37" Tires and now guys are running 39" tires. I have seen Guys running 6.0 gears.

I am use to racing in Baja and we don't even use the 4wd most of the time and only engage it if needed. Do you plan on using the front axle all the time. You would run faster in two wheel drive and use the front as needed, but your course would dictate the use of it.

[Silverslk]

I think we were running 6.0's in the ProTruck (with the 650hp motor) on 37's but it was 2wd....

[Crawlfab]

Yea it will be in 4wd usually the whole race with some times in 4 low. I will see ho the gearing works out. I can run 37" tires in th class but plan to run 35s.

Here are more videos of the racing to get a feel for what im trying to do with a full body bronco.

Also this build has to be done for the first race in texas on march 15th.

First video is the class I plan to run. This was the winning rig last year at the national race.
http://www.youtube.com/watch?v=BCS1jNBlugg


Here is a lap on another course. its been a long time since I have ran a bronco but I feel it can handle this terrain with ease and more speed.
http://www.youtube.com/watch?v=8R9bgveOW6A

[Crawlfab]

Well my mod class rig ended up looking like more then I wanted to throw my wife into off the bat. So I went out and purchased a $300 1986 bronco on craigslist to build for stock class this year.

We Just ran the first race with it and it worked pretty well but in the front but the back is way loose. She had zero seat time in the rig before the race but it looks to be a handful to drive. She did manage 4th running one class up from us against full built tube chassis rigs. Had a fuel pump issue the first day and only ran one lap compared to a 6 lap day 2. Needed 10 laps for 3rd. Even dumped the rig on the drivers side day 2 and got it back on its wheels.

I put 4" pro comp coils/arms with C/t beams on the front running 4 bilstein 5100s. On the rear its the stock pack with a add a leaf after the main with 12" bilstein 5100 255/70 valved. I stripped it down as much as I could and it feels pretty light but the rear suspension needs lots more rebound valving. Not sure what I can do as in the stock class I have to run sealed shocks. Anybody have any sugestions on the rear? I need to put a spare on the back or maybe even the tail gate to get it settled.

[Wrightracing.net]

On of the old tricks with shocks is to run ones you can rebuild. Then get them tuned for your setup and then weld them shut and paint. Or then order New ones with the same setup from Bilstein in a closed shock. With the leafs, get a set from National or Deaver. Make sure to weight the rear of the Bronco being supported by the leafs and weight the axle with your wheels for the unsprung weight. Give the spring maker those weights and the rides height you want to run. I recommend staying as close to stock as possible but push out the inner fenders for clearances, check you Promoters class rules. The reason for the height is to keep the center of gravity down.

Are you racing in a closed course or cross country - desert environment.

Show us some pictures. If you have not yet, pull the shell and tailgate. I notice a major difference in the weight to power ratio on my Bronco.

Oh and don't tune the shocks until you get new leafs. And make sure to upgrade to double military wrap leafs and upgrade the u bolt to RV 5/8 or 9/16.

Than would be a good starting point. If that is not in the budget then play with adding full leafs of different rates from the junk yard until you get the feel and ride height you want. If your rules allow, get longer rear shackles to lower your ride height with leafs that are thicker and gain some more wheel travel.

[Rmc]

I agree with wright. Lots of tricks to look stock but isn't.

[Crawlfab]

Here is the rig. 1986 302 with aod, 4.10 gears, dana 50 front third, 35" km2, pro comp arms 4" coils, cut and turn beams. Its fully stripped minus windshield and the dash.

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[Crawlfab]

The courses are a mix. This race is fence line stuff, steep climbs, ditches, rock sections, big down hills. We run 60+ in the fence line areas and say 1-5 mph in the rocks.

[Crawlfab]

The rear spring rate in it now feels good but the rear shocks seem way off. Compression side feels good but rebound side is way soft. She ran off a x on the track that was a 4' ledge at probably 30 mph and it was a good landing but then the bounce kicked the ass 2' to the side. It rebounds off ledges and tries to pass the front running fast.

I built a rear mount to lay the shocks all the way to the floor like the ones that are sold from vendors. They are the stiffest valved 5100s they sell.

I may test the rules in the class as it has no mention of how many shocks I can run but says non adjustable shocks only.