Thoughts on my first 1/8th Scale monster truck??

[NitroBlood_92]

Wadup guys, call me NTB for short.
New to the forum just introducing myself and my current RC project to the scene.
I got my engineering degree from SIUC so building and fabricating

are no strangers to me.

A couple months ago I did the impossible and tried to make a monster from one of the most finicky and hated on chassis in the industry.....The Cen Racing GST 7.7 3speed

The fact that it's gigantic and complex made me want to keep it despite the poopy engine lol. A lot has been done to this truck.
-Aluminum upper/lower control arms
-Aluminum Strut towers
-Aluminum steering knuckles
-Aluminum servo saver
-Hitec Titanium gear High Torque servos (steer+throttle)
-23mm Hub conversion
-4 Wheel Steer conversion
-Dual mass clutch upgrade
-17/21 Hardened steel clutch bell
-Fuelcooler and check valve mod
-Custom billet Tank Cage
-Hitec Fuel Tank
-Cross Shock Upgrade
-HD White coated stiff springs
-Dual hardened steel stabilizer links
-Front+Rear aluminum differentials
Swapping the motor next week for something with a wider revband to make it a little more flexible in the straights.

You may ask why the hell would you build a CEN truck....well.....why the hell not when its this badass lol

 

[HPIguy]

Welcome to RNCT!

What's the purpose of the cross shock upgrade? It appears to be trying to mimic a sway bar setup. If that's the case, then to get any benefit the shock would have to be so stiff that it serves no purpose being there. Or, If you have the shock soft enough to have some absorption, then it isn't doing anything the shocks attached to the arms weren't already doing. The Dual mass clutch upgrade also, how does that work?

Not knocking your build, just genuinely curious.

 

[NitroBlood_92]

Welcome to RNCT!

What's the purpose of the cross shock upgrade? It appears to be trying to mimic a sway bar setup. If that's the case, then to get any benefit the shock would have to be so stiff that it serves no purpose being there. Or, If you have the shock soft enough to have some absorption, then it isn't doing anything the shocks attached to the arms weren't already doing. The Dual mass clutch upgrade also, how does that work?

Not knocking your build, just genuinely curious.

You are 100% correct about the cross shock being useless unless its ultra rigid, I've since experimented with it on and off the truck and noticed that it doesn't flip over as easily on high speed sharp cornering. I've added a significant amount of tension via spring seat spacers to the front cross shock and a bit more to the rear to keep it from fishtailing on a hard launch.

Think of it as an adjustable damper setting.
This motor only spins to 23k rpm but the torque twists the truck, so stability is added.

As for the clutch, I have a 4 puck setup. Two adjacent are carbon composite and the other two are a lightweight aluminum alloy. Before the upgrade the throttle was twitchy on launch and a bit annoying, this setup makes it incredibly easy to slowly cruise around before the 2nd gear engages and bogs the motor.

I'm super picky haha

You are 100% correct about the cross shock being useless unless its ultra rigid, I've since experimented with it on and off the truck and noticed that it doesn't flip over as easily on high speed sharp cornering. I've added a significant amount of tension via spring seat spacers to the front cross shock and a bit more to the rear to keep it from fishtailing on a hard launch.

Think of it as an adjustable damper setting.
This motor only spins to 23k rpm but the torque twists the truck, so stability is added.

As for the clutch, I have a 4 puck setup. Two adjacent are carbon composite and the other two are a lightweight aluminum alloy. 2 engage until about 1/4 throttle, then the carbon composite grip and eliminate bell slip allowing full energy transfer. I like to believe it stresses my spur gear less.

Before the upgrade the throttle was twitchy on launch and a bit annoying, this setup makes it incredibly easy to slowly cruise around before the 2nd gear engages and bogs the motor.

I'm super picky haha

 

[cbaker65]

What took you so long to become bada$$?....

 

[Nitrotrout]

You may ask why the hell would you build a CEN truck....well.....why the hell not when its this badass lol

I really enjoy unusual build projects like this. Looks like you put a lot of time and money into creating your rig and it's unique. Well done man.
I'd like to see some videos of your truck next time you run it.

 

[NitroBlood_92]

What took you so long to become bada$$?....

Not having any parts at my LHS for one, The rest was spent taking it apart down to each gear and bolt just to rebuild and correct any errors, almost sold it after I accidentally flipped a ring gear in the diff, did stationary burnouts all day HA!

I really enjoy unusual build projects like this. Looks like you put a lot of time and money into creating your rig and it's unique. Well done man.
I'd like to see some videos of your truck next time you run it.

Thank you, I take pride in all my projects and aim for perfection. There's no fun building the same thing everybody else has I love the frankensteins haha.

I will be running it after work, there'll be videos posted by tomorrow

 

[Meowzz]

It certainly is a very nice build, however creating it to have 4 wheel steering will surley flip and tumble with the speed it will be flying around at. It's pretty badass but the steering I would pass.
My favourite Cen was the gx1.

 

[NitroBlood_92]

It certainly is a very nice build, however creating it to have 4 wheel steering will surley flip and tumble with the speed it will be flying around at. It's pretty badass but the steering I would pass.
My favourite Cen was the gx1.

I thought the same thing when I was considering 4 wheel steering, I had the parts laying around so it was a free experiment.

Surprisingly by this truck weighing in around 18lbs after the cage, and a suspension that has withstood tons of trial and error, flipping isn't my concern anymore, its turning too sharply and oversteering corners. Countersteering becomes a lot more useful for corrections with a proper transmitter for D/R, ARC, and servo limit sets.

Its a freaking grocery cart with a transmitter and 5hp lol

4WS does amazing 360 burnouts haha

 

[watertrucker]

Welcome to RCNT! Nice build, man. Liked the pic next to the TMaxx.

 

[Rolex]

3 of your tires are backwards.

 

[NitroBlood_92]

3 of your tires are backwards.

I cracked the correct ones while hooning. At 100$ per set I run what I have lol

Welcome to RCNT! Nice build, man. Liked the pic next to the TMaxx.

Thanks man!

 

[cbaker65]

3 of your tires are backwards.

3 of your tires are backwards.

No ,only one is,3 of them is put on right !....

The truck looks good ,those rollcages were quite expensive!..

 

[Meowzz]

I thought the same thing when I was considering 4 wheel steering, I had the parts laying around so it was a free experiment.

Surprisingly by this truck weighing in around 18lbs after the cage, and a suspension that has withstood tons of trial and error, flipping isn't my concern anymore, its turning too sharply and oversteering corners. Countersteering becomes a lot more useful for corrections with a proper transmitter for D/R, ARC, and servo limit sets.

Its a freaking grocery cart with a transmitter and 5hp lol

4WS does amazing 360 burnouts haha

You may be able to eliminate the flipping, by adjusting the turning ratio on the rear wheels, may help with flipping over. And I bet it does do some mean peels

 

[NitroBlood_92]

You may be able to eliminate the flipping, by adjusting the turning ratio on the rear wheels, may help with flipping over. And I bet it does do some mean peels

That's a good idea, ill try a lower viscosity diff fluid the next time I end up tearing that thing apart.

 

[Meowzz]

That's a good idea, ill try a lower viscosity diff fluid the next time I end up tearing that thing apart.

No no no haha I don't mean the diff, I mean the angle at which the steering is at.

 

[NitroBlood_92]

No no no haha I don't mean the diff, I mean the angle at which the steering is at.

Oh haha I've messed with the toe angles already. And the servo has a lesser turning radius than the front

The resistance in opposing rotation between both axles in the diff will definitely cause oversteer. Gotta find that balance

 

[Meowzz]

Oh haha I've messed with the toe angles already. And the servo has a lesser turning radius than the front

The resistance in opposing rotation between both axles in the diff will definitely cause oversteer. Gotta find that balance

How ever remember this, it may lower the ratio of how quick the diff rotates at but adding thicker viscosity diff fluid CAN cause more strain on your engine especially on a cold day. Try fiddling with the servo horns and using shorter linkages, I'm still impressed you pulled it off

 

[NitroBlood_92]

How ever remember this, it may lower the ratio of how quick the diff rotates at but adding thicker viscosity diff fluid CAN cause more strain on your engine especially on a cold day. Try fiddling with the servo horns and using shorter linkages, I'm still impressed you pulled it off

That's true I didn't think of it that way, here on the west coast it doesn't get too cold but better safe than sorry with a 300$ engine smh.

I'll start at the servo horn for sure, might take some strain off the servo motor as well to save battery.

 

[Meowzz]

That's true I didn't think of it that way, here on the west coast it doesn't get too cold but better safe than sorry with a 300$ engine smh.

I'll start at the servo horn for sure, might take some strain off the servo motor as well to save battery.

Yes I hope to see it in action very nice build hope you keep me updated and just reply if you need a question answered.

 

[NitroBlood_92]

Yes I hope to see it in action very nice build hope you keep me updated and just reply if you need a question answered.

Will do thanks!