U4RC 2.2 Trophy rig "Bad Attitude"

[Rockpiledriver]

3 weeks ago I decided I wanted to race 2.2 Trophy class in the U4RC Rock Racing Series. 2.2 Trophy is a class for builders, with the main emphasis on scale rock race appearance and of course performance. Class specs can be found here: U4RC Current Class Specs/Rules

This is my attempt at a 2.2 Trophy class specific rig. I'll go over some of the things we did in the build, but with only three weeks to finish it, there was no time for a regular build thread.

Here is a pic of the finished rig just before I tossed it onto the track for the first time.

[Rockpiledriver]

One thing I had to have was an FJ40. One problem with that, is the distance from the grill to the dash isn't all that long on the old Proline body. about 1 week into the build I knew I was going to have issues keeping the grill while allowing the suspension to cycle fully and unrestricted. As I was about to accept loosing the thing that makes it an FJ40, the grill, I ran across this!
AR60/Wraith Servo/Truss/Link mount

Thanks to Erik D-Lux I got to keep my grill and cleaned up the appearance of the front axle at the same time.

The other cool thing the truss did was allow me to add separation between the 4 link mounts at the axle. This rig exhibit very little if any torque twist.

[boostnloose]

Are those twin vaterra rear links?

[Rockpiledriver]

Thanks boostnloose. The rear links I made years ago for a clod based super build. I always planned to do trailing arms, but in the short time frame I had, I was ready to run axle mounted shocks. Then I found the arms laying in a box, and realized they would work perfectly for this rig. They also made it easy to mount the sway bar. The sway bar is a must have item on a U4RC rig in our opinions. One of the arms came off halfway through my first heat and it made a huge difference in the overall stability of the rig. So much so that people said they noticed the difference in my handling at the beginning and the end.

[STANG KILLA SS]

been following on facebook

[Rockpiledriver]

This class has a minimum weight of 8 lbs. By using stainless steel tube instead of solid rod for the chassis, we were able to build in all of the structural support we needed, and still had keep the chassis very light. I decided to go with the plastic Axial beadlocks to keep the un-sprung weight down also. The rig weighed in at exactly 8 lbs on race day. Since this is a solid axle front, we kept the rigs stance pretty low. In fact, the front lower links actually angle down, going from the axle to the skidplate. This way, the front suspension does not have to cycle forward before it cycles back and up. I need to tune a bit more on the shocks still, but it worked pretty good as is. The travel in front is about 40% droop and 60% up. The rear is the opposite. I like the rear to fall away significantly like a trophy truck. So far I like it. It does not bottom out bad at all on big jumps.

[tedo]

cool. It has a wicked mean stance. Looks great with those RBIIs.

[ngward79]

Looks killer man ! When you get a chance snap some pics without the body on her.

[boosted4lyf]

Oh my gawd! That thing is bitchin!!

[Rockpiledriver]

Thanks guys, much appreciated! That said, this would never have happened if it was not for some help from friends and family. First off Shawn Jones at Jones Fab in Upland, Ca for doing this so quick and letting me put my twist on it. Indysand from here, for allowing me to use the servo/link mount he bought for his upcoming build. The Doc for helping get the tires and foams on a few days notice. Crawler Innovations for cutting me a set of foams and shipping them same day!!!!! Todd Torbenson for the paint and graphics. The clear coat was still wet when we arrived at the track so that Matt Frederick could shoot these amazing pictures that I get to share here. My lovely wife for putting up with me being out almost every night for three weeks. And of course, the U4RC sponsors for giving me a reason to do this. Thanks Everyone!!!

The first heat went great for me. It took some time getting used to having more steering than I need. Another issue was, I ran out of money for VP knuckles and C's and ran the stock plastic ones for this race. But you know what? They held up fine, even when I lost the tie rod due to a bolt falling out. Poor prep by me. Imagine that. Shawn had me back on the track in about a minute, and I finished the heat in third transferring to the main.

[axelsnapr]

That thing definitly came out awesome Brian!... It was very impressive on it's first race outing. I am sure it will be a force to be reckoned with in the 2.2T class at U4RC events. Great job by Shawn at Jones Fab too!

[Rockpiledriver]

The main event didn't go we'll. I guess the vxl I was running could not keep up even with reasonable temps and 2s. About 1/3 of the way through the first lap of the main it stopped. Got it back to the trailer plugged in another pack and it worked but it was too late to get back out the next day I checked it all out plugged it in and went to the front yard. This happened. I was lucky it didn't burn down. The aluminum inner fenders and electronics mount saved it I think.

[ngward79]

Originally Posted by Rockpiledriver

The main event didn't go we'll. I guess the vxl I was running could not keep up even with reasonable temps and 2s. About 1/3 of the way through the first lap of the main it stopped. Got it back to the trailer plugged in another pack and it worked but it was too late to get back out the next day I checked it all out plugged it in and went to the front yard. This happened. I was lucky it didn't burn down. The aluminum inner fenders and electronics mount saved it I think.

Attachment 263543

What are you running for gear ratio ? I currently have a vxl in my Trent Fab buggy and seems to do ok on temps running 3s but my gear ratio is 6:1 with 32 pitch 10 tooth pinion and 60 tooth spur. But again, I haven't ran it that hard for that length of time though either.

[Rockpiledriver]

Originally Posted by ngward79

What are you running for gear ratio ? I currently have a vxl in my Trent Fab buggy and seems to do ok on temps running 3s but my gear ratio is 6:1 with 32 pitch 10 tooth pinion and 60 tooth spur. But again, I haven't ran it that hard for that length of time though either.

I was running 19/87 on 2S. I thought I was fine but it was a used borrowed esc. It was all I had. My Twin Hammers needs a total rebuild so it just lost the ROC412/RS combo to this rig. I've tested it briefly at 17/87 and it's plenty fast, so I may gear down further to try and make the RS last. I need a MMP or R8.

[ngward79]

If your running that gear ratio with the roc 412 on 2s it should be ok, even on 3s I would think it would be ok. I would probably run it on the 19 /87 cause that would be about a 5:1 ratio and shouldn't over heat on 2s.

[ngward79]

Forgot to ask what the kv was ?

[Rockpiledriver]

3100 and its going to run 3s. That's why I'm thinking of dropping the pinion 2 more teeth. Here is a RTR pic minus the body and rear bumper... Uhhh, I mean spare tire...

[Rockpiledriver]

[doublej]

nice and simple - Me likey....
I noticed the plastic rims - Do you run any weight in them with the high speed stuff?

[Rockpiledriver]

Originally Posted by doublej

nice and simple - Me likey....
I noticed the plastic rims - Do you run any weight in them with the high speed stuff?

No, I want all un-sprung things like axles and wheels light. I'm trying to keep the CG centered in the chassis at the bottom. I will be running aluminum C's, knuckles, and hubs for the plastic wheel before the next race. Or right after I shred the plastic parts. They won't come off until they fail.