Mad Max Dune Runner

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Would there be any advantage to having wider a-arms on the front of a 4wd than are on the rear of the car for sand drags? Or vise versa ? This would give each set of axles its own fresh line to run in. Seems like this would get and keep a 4 wd on top of the sand sooner--- just a passing thought, what do you folks out there think?
 
I had been looking at the Saudis drag racing uphill with the 2wd cars on you-tube. the cars sorta sink into the dry sand for several feet before they get up on top and get moving-- soo it does stand to reason that this would more or less bury a 4wd -- especally if the 4wd had 5-b paddles front and rear, even when it did get up and moving, the rear tires would be digging into the loose roost from the front. - There was a vendor here a while back that posted photos of cnc a-arms he was making, rears at the time- I think? that wider on the front could be better? - for sand drags anyways--
 
Also, when stopping the vid of the Saudis drag cars before launch-- one of the cars had a wt series carb that had a additional plate under the white fuel bulb plate- Think the idea here was to have higher volume of fuel in the needle valve area- less chance of fuel starvation- You can get these wt equipped cas we all use- rev the engine up on a stand and see the fuel bulb pretty much turn to foam-- this is why i run a higher fuel level in the bulb about 90% full while the car is ideling --they seen to hold a better tune, not go lean @ wot .
 
many posts this AM- after the 5th cup of high test joe- i have hit my target heart rate---- On the wt series carbs-- leave the fuel bulb as is, get a 2nd fuel bulb plate- gasket. cut out the diaphram and just use the gasket. bolt the gasket - plate on top of the first one- just need longer screws- I sorta have troubles getting this idea on e-mail- in the correct sequence- order- but you carb guys can see what i am saying-- This would increase the volume of gas - who knows huh?
 
I'm trying two things at first.

1. 5b paddles on the rear, 5T Trenchers on the front. The DR is set up with diff fluid that places most of the power on the rear, I think with the paddles on the rear, the front will pop up on application of power at the start, so the front should skim the surface. Driver technique plays a large role here, throttle control is important.

2. If 1 doesn't work, try front paddles.

3. Go from extended hubs on the front to regular hubs, or vice versa.

I won't go 2wd, got a 5b with the same engine for that. But I think I can get a credible 4X4 sand buggy built. A little challenge, keeps you thinking.
 
alfred e numan said:
many posts this AM- after the 5th cup of high test joe- i have hit my target heart rate---- On the wt series carbs-- leave the fuel bulb as is, get a 2nd fuel bulb plate- gasket. cut out the diaphram and just use the gasket. bolt the gasket - plate on top of the first one- just need longer screws- I sorta have troubles getting this idea on e-mail- in the correct sequence- order- but you carb guys can see what i am saying-- This would increase the volume of gas - who knows huh?
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Good observation. Something I'll keep in my back pocket. No one runs a 4X4 sand rig (except twins or 70cc + engines), so it's like Star Trek, "Going where no one has gone before."

And on any other drag race rig! Any advantage is good!!

One thing I use is a Team Chase filter to keep the vent hole at the diaphragm from filling with dirt. It works.

Thanks.
 
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Prostroke is out of the buggy, ready to be dropped off tomorrow when I pick up the OBR built 5b, 30.5 3mm long stroke, custom paint buggy. Hint, the paint job is NAVY!

The Prostroke will be a Pro Build Losi, and I won't have anything indicating it's other then what I was running before. OBR builds Zenoah engines, the DR needs a HY fan case, so I stripped everything off the engine. So unless you look closely when I reinstall everything, ... Sleeper.
 
The Pro Build 30.5 Losi build has left OBR today. And I recieved a new Killer RC Power Start.

Should be running this weekend.

Would of been faster if I hadn't forgotten the engine when I went to Torrence Monday last week to pick up my custom OBR 5b. Guess I was excited. :D Sean posted pictures of the 5b on the OBR site, and in the OBR thread on the HPI Baja Forum for me while we were on vacation last week.
 
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The OBR Full Mod Losi 30.5 ported upgrade was waiting when I got home from work. Saturday it goes back together and we'll see what we see.

Check the build date 7-4-2013. Born on the 4th of July!

 
The Dune Runner is now back together with a OBR Pro Build Losi engine on a Victory Big Bore side pipe and a 8K clutch. Tomorrow it's break in and after that finding out what the DR will do for max speed, using a GPS.

It will be running on gravel, with Trenchers so I won't get any info using paddles in sand.

Sorry... :)
 
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During the break in of the new engine I discovered the plastic OEM CY intake manifold I was using warped after the engine warmed up. I couldn't find any cracks, so that's my best guess. Went from rich to lean before I even got the idle adjusted. Just got a billet manifold from DDR and I'll be trying it out in the morning.

Nice thing about the DDR billet manifold, no more cardboard gaskets. The billet manifold comes with plastic (Teflon?) spacers instead.
 
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Yep, they are awesome. No more warping issues. Just make sure you fit them to allow the breather holes to work, both sides of the manifold...... :)
 
I use the ada intake. billet. I do not use the teflon gasket between the intake and jug. I use the ddm stainless steel- graphite gasket. Torqued down to 8 or 9 N/M. Use a 1/2 drop red loktite on each bolt. The carb to intake teflon gasket is used. Torqued to 6 or 7 N/M. Agan, about 1/2 drop of red loktite is used on each bolt. When the carb is removed, I use a thread tap to clean up the female threads. Zero issues with gallons of fuel tru assorted engined with this set up. Only torque like this with an after market intake- drop kick the plastic intake far as you can.- aim for a garbage dumpster.
 
On this area of the engine, I donot use a clicker style torque wrench. I always use a K-D tools beam style torque wrench. Soft teflon and a clicker torque wrench is not good.
 
Some days you are the Bear, other days you're Bear Scat. Now it's spark, or rather, lack of. Couldn't even get a pop. Cap is good, lead looks OK. Checked the spark, and the best spark I got was straw colored, not a blue spark. Reset the mag gap (3 times), checked the plug gap at .029, and still the same. Weak spark. This is a aftermarket mag I got after the OEM plug cap and lead got damaged. All this was hidden while using a Power Start, but at the sand drags I don't feel like carrying the drill motor as you start the engine just before you stage. So, getting everything set to use a pull start, hello. The intake upgrade I'd planned on for some time, the ignition, well, there you go.

Back to DDM for a new mag. Hope it isn't the flywheel magnets. And it's a new spark plug.

And the body broke in two places, just under the fill neck and at the front edge of the fan cover when the starter handle slipped out of my hand and rapped the body. Guess they get brittle over time.

Sigh.
 
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Coil specs.

Yea, I wish someone would wind a hotter coil. I have read that setting the coils air gap will give a hotter spark-- 0.3 mm. Here are coils resistance specs. All measured in Ohms. Primary- 0.7 -Reading between primary termanal and iron core. Secondary- 6100. Between plug cap and iron core.
 
Warped intake manifold, weak spark. What a mess! :(

Dumpster, HE**! I tossed that manifold and mag so far into the desert, GOD COULDN'T FIND IT!

USPS says the new mag, plug boot and cap wire should arrive tomorrow. The mag I tossed came assembled, when I think back, the problems with getting the engine started began when it was installed. Isn't hind sight wonderful. :rolleyes:

I REALLY want to get running. Sand Drags on the 17th. And a OBR 30.5 Probuild Losi build to break in, and tune before then. Thought I'd get a couple of weekends at the track to practice and set up, THAT isn't happening.
 
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Dumpster, HE**! I tossed that manifold and mag so far into the desert, GOD COULDN'T FIND IT!
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