SCREAMER's IFS Bomber "Qwiksilver"

[SCREAMER]

Got the rest of my parts in for my front diff so I decided to throw it together. Here's the parts list I used.

Hot Racing diff cup, part # AEX11C01
Axial HD diff outputs, part # AX30381
Gravity RC 20 million weight silicone
Axial diff gasket, part # AX30385
Axial E2.5 E-clip, part # AXA1393
Axial 5x1mm O-rings, part # AXA1162
Axial HD bevel gear set 43/13, part # AX30402
HPI spider gears, part # 86014
Fast Eddy ceramic 10x15x4 bearings

You can see it's a lot more involved to go with an open diff but I'm hoping it's worth it. Initial thoughts on the Hot Racing diff cup and HPI spider gears are very positive. They both feel like high quality components that are machined to very strict tolerances. The Gravity RC silicone feels awesome. After assembly, I immediately started twisting the outputs to get a feel for how much resistance it would provide and it seems to be perfect. It's very smooth and almost has a valved feeling to it as you start trying to spin it faster. I'm very excited to try this setup. Everything went together with no issues and it definitely feels like a stout piece, we'll see soon enough.

[Rjohn929]

I just picked up that housing and the HPI spiders for my SMT. I really hope they outlast the the stock gears. They made it about 3 minutes. I agree though, The quality feels great.

[SCREAMER]

I never messed with the Axial spider gear set because I always read that the HPIs were a significant upgrade. I also never saw anyone post a part number so when I finally found which ones they were I had to share the info. It's crazy to me how they just so happen to fit the Axial axle shafts and Yeti outputs perfectly with no slop, just like they were made for each other.

[*Old*]

So will you be running UD gears front and rear then? Curious why you chose that for your "go fast" rig?

[SCREAMER]

Pulled the front diff off of the old B1B chassis plate and converted it over to the rear setup. I was lucky enough to find probably the last brand new Vanquish Exo rear camber link mount in existence and as luck would have it, it was orange to match the rest of my VP goodies. STRC and Hot Racing both make these still so that shouldn't be an issue for anyone to get one. Also had to pull the front toe blocks and swap them with the Exo rear pieces. I was very happy to discover the inside of the DLux diff housing was completely clean and still spun smooth and freely. All my expensive ceramic bearings seem to be doing their job. Anyway, here's the list of parts I used for my complete rear diff assembly.

DLux modified big bearing housing
DLux Yeti front axle shafts with diff cups and HD locker pins
Axial Yeti/Exo locker, part # AX31182
Axial Exo aluminum rear toe block set (R1and R2), part # AX30864
Axial chassis guard and toe block insert set, part # AX80100
Axial HD bevel gear set 43/13, part # AX30402
Fast Eddy ceramic bearings, 10x15x4, 5x13x4, 5x11x4
Vanquish Exo rear camber link mount

[SCREAMER]

Originally Posted by *Old*

So will you be running UD gears front and rear then? Curious why you chose that for your "go fast" rig?

43/13 has the best gear mesh of the three options, they also reduce torque twist, I'm using the same front and rear so when I stab the throttle I can steer with the rear, I run mostly 4s now so wheelspeed isn't an issue. If I need more I can always gear up on the pinion.

[*Old*]

Originally Posted by SCREAMER

43/13 has the best gear mesh of the three options, they also reduce torque twist, I'm using the same front and rear so when I stab the throttle I can steer with the rear, I run mostly 4s now so wheelspeed isn't an issue. If I need more I can always gear up on the pinion.

10-4! Thanks for the info. Good to know

[SCREAMER]

Got my chassis today from Jerry and it was better than Christmas. Everything was very well packaged and each piece looks so nice. I didn't get started on it as early as I had hoped and I'm actually still waiting on some parts like bearings and my DLux modified housing for the front. I had to at least get going with assembly so I started installing the rear drivetrain.

You can see from the first pic there's a significant gap in the mating surface between the bulkhead and the chassis plate. I encountered this with my first IFS build and as I mentioned before, this is caused by high and low spots on the bulkhead itself and seems to be a bit worse in the rear due to the toe blocks. The answer is just a small bead of your choice of RTV or silicone gasket maker. I went with Bomber blue this time instead of gray. This is such an important step and I hope everyone takes the time to do this for the front and rear because I learned the hard way, the tiniest gap will let in more sand and crap than you can imagine in less than a pack. When I pulled my front end apart to prepare for this build, I was amazed at how clean everything was. No contamination whatsoever to the grease or bearings and everything spun smooth.

Jerry did such a great job with his design on this chassis. So far, everything is lining up perfectly with no forcing or fighting. The bulkhead and rear skid/chassis brace lined up perfect with the bottom plate and the Hot Racing brace fell right into place with all holes lining up perfectly. I appreciate this kind of effort so much because it just plain sucks when you start a build and everything is off or you have to remove material or ream things to get lined up. This felt like I was reassembling an RTR. So nice. The Hot Racing brace is a nice little piece with the aluminum arm and carbon fiber bracket and it even came with high strength hardware for all the necessary mounting points.

That's all for now. Got my fingers crossed that the rest of the necessary parts show up soon so I can continue. I might steal some bearings from another truck so I can get the rear arms installed and the camber links dialed in. I can also get the trans mounted and rear driveshaft cut and installed. More to come!

[cmbscx10]

Looking awesome and as always thanks for the detailed pics and info. Look forward to the finish and running thoughts.

[Lanky]

Wow! Looks killer! Pumped for you, cant wait to see this thing together!

[Deckard]

This thread is now painful for me to read. I'm staring off and have a tear rolling down my eye, dreaming of building a B2B. lol

Great info and details. As usual. Thanks for providing such detail. It's appreciated.

[bigbody]

Originally Posted by Deckard

This thread is now painful for me to read. I'm staring off and have a tear rolling down my eye, dreaming of building a B2B. lol

Great info and details. As usual. Thanks for providing such detail. It's appreciated.

This... I bought a rtr bomber right at a year ago, my first hobby grade rc. I had no idea what I was getting into. Since I found this site I have been drooling over these B1B builds. I just pulled the trigger on my own B1B kit (#3 and SCREAMER and Bilinvic's threads have been more than informative and are what made me decide to go for it. I just want to say thanks because you guys put so much time and effort into being thorough and helpful that it inspires newbs like myself to learn and try new things.

P.S. I'm eagerly awaiting your progress on this new project. Very interested in that 20 mil diff putty, and a little jealous. Thanks again.

[SCREAMER]

Got some more parts in today and made a little more progress. I was able to get the rear arms mounted and went through my Bag-O-random-links until I found the perfect camber links. I know they're Ti VP links but have no idea what they came off of. I'll put the eye to eye length below in the parts list. Again, everything went together with no hiccups and the entire rear driveline spins smooth and freely through the entire cycle of travel. I also got the transmission and motor mounted and I'll continue using my ESC "shelf" to hold the MMX. "If it ain't broke..."

I'm going to use an Axial WBHD driveshaft in the rear for now, the TMaxx shaft did just barely clear everything but it was a little too close for comfort so I had to go with something a bit smaller. I'm going to look for a dog bone and cup setup because that would be ideal in a non telescoping application like this.

One last thing I would highly recommend that came in handy with installing the rear hubs is a KNK aluminum spacer kit. I used two 3mm spacers on the front side of the rear hubs. The kit comes with 10 each of several different sizes and will be nice to use on builds from now on.

Hopefully my DLux diff housings show up tomorrow then I can finish this bad boy and get it dirty this weekend. Stay tuned.

Parts list:

RPM Exo rear arms, part # 70452
VP Ti camber links, 93mm eye to eye
VP clamping hexes
DLux Yeti FBA axle shafts
STRC Exo rear hubs, part # STA80104-O
Hot Racing rear chassis brace, part # AEX13GX03
Fast Eddy bearings for the hubs, 10x15x4 and 5x11x4
12.9 grade m3x61mm inner hinge screws for the RPM arms

[bilinvic]

Lovin' this transformation Brian and I'm looking forward to seeing the progress.

[SCREAMER]

Thanks Bil, I'm pretty psyched to see mine and yours.

You guys are gonna love this, at least I think it's awesome. With a Wraith transmission bolted into the chassis, the center driveshaft lengths are identical, front and rear. They are exactly 107mm long, that's screw pin to screw pin. I have a brand new stock complete front diff assembly out of a Yeti Score that I used to mock up. Tracking on my DLux bulkheads shows Monday as the delivery estimate so I may leave this stocker installed so I can run this weekend. I'm just too damn impatient.

So with the front diff installed I was able to get the center front driveshaft installed. It was the TMaxx shaft I measured and cut for the rear so because they are identical lengths (I still think that's awesome) it was perfect for the front with miles of clearance everywhere.

Another thing about the layout of this chassis is the gratuitous amount of room behind the motor. It's going to be really tempting not to throw a monster motor in this truck now. You can see by the pics, there's motor room for days. A Holmes 540XL or even a Castle 1515 would still have room to stretch its legs. Hmm

That's all for tonight. Gonna let the RTV on the front bulkhead cure then tomorrow I'll get the front arms and suspension installed then get the cage mounted if I get time. I want to mention again, how nice this kit is going together. No fitment issues or clearance issues of any kind. Knock on wood, I have a feeling the cage will fall right into place.

[bilinvic]

Your excitement is contagious!!! I assume you have a non-production chassis plate because I thought I read Jerry is machining a solid plate and it appears yours has the raised mounting edges welded, correct?

[SCREAMER]

Yes, mine was handmade by the man himself and the side rails were welded on. The new plates will have an updated shape as well as be machined from a single piece of 1/4 inch thick 7075. The plates will be machined down to 1/8 inch thick everywhere but the side rails which will remain 1/4 inch thick where the cage mounts.

[bilinvic]

I would think that the Axial WB shafts should be plenty strong and would be an easy replacement/weak link if they do let go. I'd rather replace one of those than the axles or diff gears.

[bilinvic]

In that last picture, are the rear A-arms at full droop?

[SCREAMER]

Oh no, they are just holding themselves in place from laying flat. Gotta break in a bit. It's a pretty tight fit initially between the toe block inserts, especially in the rear. Let me grab a pic of full droop and post up.

Edit: Here's full droop and full uptravel. Uptravel is actually limited by the drive cup hitting the arm itself. 5 minutes with a Dremel would clear that up but I'm not sure the shocks will allow anymore travel anyway. If you use the baseboard as a reference point, you can see there's a lot of swing. This truck is going to soak up some major hits and be so incredibly plush, I'm dying to drive it.