Boldfin's VS4-10 with VFD Trans and TRX-4 Axles

[boldfin]

I'm a newbie still, and this is my first build thread, so go easy. I have modded some RTR's and built a couple of kits, and generally have been having a great time messing with these little trucks for about a year. When the VS4-10 chassis came out, I bought one right away, with the intention of running TRX-4 axles under it to take advantage of the high-clearance design. I bought a set of takeoff TRX-4 Sport axles, and started accumulating additional parts:


Chassis:
VS4-10 Chassis Kit
VS4-10 Extended Shock Tower Clear Anodized (Front and Rear)
Vanquish Products VS4-10/VFD battery and electronics trays
Incision 90mm scale shocks (with soft springs from Incision Scale Shock Spring Set)
Incision Driveshafts for SCX10-2 RTR and SCX10
Incision SCX10-II 12.3" 1/4 Stainless Steel 10pc Link Kit
Incision TRX-4 Stainless Steel Drag Link and Panhard for VS4-10
TRX-4 Sport Axles (Stock gearing in Front & Underdriven Rear)
SSD TRX-4 Brass Portal Weights (front)


Electronics:
Hobbywing AXE 540 2300KV Brushless motor and ESC Combo
ProTek 370TBL servo
Vanquish Clamping 25T Servo Horn 20mm
Spektrum SR315 receiver
Castle Creations BEC 2.0 Waterproof


Initially, I was going to just run an Axial 3-Gear Style transmission, but then the VFD Transmission kit came out, so I decided to try to give that a try. I viewed the very informative videos that Harley put on on calculating FDR and choosing a Spur/Pinion combo to compensate for the gear reduction of portals. I chose to go with a 50T Spur with 21T pinion based on suggestions from members on RCC.





Last night, I started assembling the chassis:







I had a choice to make with regard to the link set to be used. Before the special panhard and drag links to run the TRX-4 axles on a VS4-10 chassis came out, I had previously purchased the Incision TRX-4 Stainless Steel 10pc Link Kit - 12.3in Wheelbase. But when the special panhard and drag links came out, they recommended the following:

Incision TRX-4 Stainless Steel Drag Link and Panhard for VS4-10

This link set is to be used when installing TRX-4 Portal axles into a VS4-10 chassis kit. It is recommended that you use a SCX10-2 12.3 Incision link set in combination with this kit to complete this process. The two links included in this package will replace the drag link and panhard included in that kit.

So I bought a Incision SCX10-II 12.3" 1/4 Stainless Steel 10pc Link Kit to use per the recommendations, and that is what I used to get to this point in the build:



The chassis sits nice and low due to the extended shock towers, but I am not sure I'm supposed to have this much caster, and I am having some clearance issues. The panhard bar is hitting the pumpkin at about halfway through the shocks' travel.





Worse yet, I'm not able to mount the VFD Trans. The front upper link is in the way.





I'm thinking the extended shock towers are the culprit. Are they not designed to work with the VFD trans? If so - that would be a real bummer, but I could switch back to plan A and run a 3-gear trans instead. But I think I'll still need to make some adjustments to the front links to sort out the panhard clearance issue. That caster seems excessive, and I'm guessing the front driveline angle will be poor unless I adjust front link length somewhat to rotate the axle forward a bit.

There's no issue whatsoever in the rear. Clearance is great. Driveline angle looks good.

So that's where I am stuck for now.

Should I just swap back to the stock plastic shock towers to drop the axles down a little? I would hate to increase the ride height, as a main goal of mine was to keep the COG low with the portal axles by using the extended shock towers.

Should I try using the link kit for TRX-4 with 12.3" wheelbase? Are the front link lengths any different in that kit than the one for SCX10-2 12.3" wheelbase?

By the way, there seems to be a lot of play in the upper shock mount. The shocks can slide back and forth about 3-4mm inside the mount. The little plastic balls that go inside the shock caps do not snap in. They are totally loose, and allow the shock cap to slide freely. Maybe that's how it's intended to be.





Any suggestions on how best to solve the clearance issues and get the VFD trans to mount up?

[distinctive pd]

Either put a nice bend in the upper link so it dives under trans or you may have to come up with your own upper link that’s possible shorter and mounts further forward or different location

[indybama]

Since u put trx4 axles under it, id try the trx4 link set for it. The scx set may be to short n lets the top of the axle roll back. The trx links may also give more room for the vfd to mount with the trx axles.

As for the panhard hittin the chunk, it could be from the taller shock mounts bringin the axle up higher. I havent assymbled mine yet, as im waitin to get the vfd trans n a set of axles. Idk if the SSD bent panhard n draglink set may help with clearance over the chunk, but it may also be the wrong length n offset the axle.

Maybe somebody else will chime in with added info. Hope i was of any help

Sent from my SM-J327VPP using Tapatalk

[GA Dawg]

Doesn't the VFD trans require an offset pumpkin?

[Panther6834]

Originally Posted by GA Dawg

Doesn't the VFD trans require an offset pumpkin?

Front is offset, rear is centered.

~ More peace, love, laughter, & kindness would make the world a MUCH better place

[boldfin]

Did some more work on this today. Got the VFD trans to mount, but still having clearance issues with the panhard bar and now - also the front driveshaft.

Steps taken:

1) Installed an offset panhard bar. (from a complete link set made by Hardcore RC specifically for VS4-10 chassis with TRX-4 axles).

2) Swapped stock TRX-4 steering link for stainless steering link from Hardcore RC link set for VS4-10 chassis with TRX-4 axles.

Panhard bar still hits the pumpkin about 2/3 of the way into shock compression stroke. I get full compression on the passenger side.



3) Per a suggestion from Brandon at Vanquish, I spaced over the front upper link to allow clearance on the passenger side for the VFD trans to mount. Took a 30mm screw and multiple spacers, but I managed to get just enough clearance.



Barely fits now, with no room to spare on either side.



Front upper link is now pretty much straight (very little triangulation). Is that going to affect performance?



4) Mounted the VFD trans and connected the Incision driveshafts.



Driveline angles look good, but the front driveshaft is pretty much stuffed into the bottom of the VFD trans skid. Picture doesn't do it justice. I can't get any meaningful amount of compression at all on that side now.







So this is where I'm currently stuck in the build.

Not sure whether the fix is just to bust out the Dremel and clearance the skid. I think if I did that, I'd have to take out a good amount of material to get the driveshaft to clear, and it looks like it would just hit the spur gear cover on full compression.

Once again... open to suggestions.

[Brandon]

Few things:

1. Maybe its the photos or an illusion but is your axle centered? Of course its going to follow the arc of the panhard link as it cycles. But compress the shocks to your desired ride height and see where the axle sits left to right.

2. In addition to the first item and whether or not the axle is centered I would be curious to see if there is a difference in link length between your current panhard and the Vanquish panhard link length. The VP link is made to position the axle so the driveshaft clears.

3. We havent tried the extended shock towers with this setup. Anything is possible, but this may be one of the items compounding the issues you're having.

Im not sure how willing you are to get the dremel out and grind some material away from the skid plate. But if thats your only issue and it allows you to use the extended towers and clear the driveshaft I would do that. Super simple mod to fix it.

[Topher Builds]

Very cool build, excited to see this one happen here.

Hard to tell in the pics but panhard bar looks a little long. Any chance you have a shorter rod end you could throw on? If you can get the axle centered a little more I think it will clear up the driveshaft issue.

You could also try one of the offset traxxas rod ends on the side that mounts to the chassis as it may give you a little more clearance in upwards travel as the suspension compresses.

https://www.amainhobbies.com/traxxas...CABEgIcyPD_BwE

For your upper front link, one option could be to have one made with a smaller diameter material.

[Brandon]

Any updates? Hoping you got it all worked out

[boldfin]

I have been in Baja for a week. Just got back today. I plan to try to clearance the skid with my Dremel this weekend. Will post an update.

[boldfin]

Before getting the Dremel out to clearance the skid, I checked a few things:

Originally Posted by Brandon

Few things:

1. Maybe its the photos or an illusion but is your axle centered? Of course its going to follow the arc of the panhard link as it cycles. But compress the shocks to your desired ride height and see where the axle sits left to right.

Axle is NOT Centered. Driver's side is offset about 8-10mm from the center line of the frame.



2. In addition to the first item and whether or not the axle is centered I would be curious to see if there is a difference in link length between your current panhard and the Vanquish panhard link length. The VP link is made to position the axle so the driveshaft clears.

The Hardcore RC offset panhard bar (which again, is made specifically for running TRX-4 axles on the VS4-10 chassis) is about 8-10 mm longer than the VP panhard link made to run TRX-4 axles on the VS4-10 chassis. So I swapped the VP panhard bar back in.

Unfortunately, the VP panhard is not long enough to mount on the axle now that I've spaced the front upper link over to the max.



The front upper link hits the spur gear cover, preventing me from bringing the axle back over any further to make the connection with the panhard bar




3. We havent tried the extended shock towers with this setup. Anything is possible, but this may be one of the items compounding the issues you're having.

It's starting to look more and more unlikely that I will be able to run the extended shock towers.

Im not sure how willing you are to get the dremel out and grind some material away from the skid plate. But if thats your only issue and it allows you to use the extended towers and clear the driveshaft I would do that. Super simple mod to fix it.

You can see where I was planning on Dremeling the skid to allow the driveshaft to clear. But I don't think that alone will solve my problem.



Any further suggestions?

[YXLER]

I was successful in installing TRX4 portals on my VS4 by using the Incision panhard/steering links and by using JUNFAC/Gmade driveshafts. I had to space the third link over to clear the skid, and under full articulation, the driveshaft touches the skid, but it does work. I have to run it to work the kinks out, but I think it'll do great for my purposes... which is purely trail runs. I am also using the stock shock towers, as the taller ones just simply won't work for this setup.

[Brandon]

If you remove the upper link and install the VP panhard link is the axle centered?

It may not be perfect as its sitting in a different position of the arc it travels due to the lower ride height (ext shock tower). But it should be close.

If it is centered once you are able to mount the panhard link at the axle then how does the driveshaft clearance look? It should be better if I am seeing the current position of the axle correctly.

Once everything clears and is mounted correctly other than the upper link, see if there is a spacer you can use to make the upper link clear the chassis and spur cover, leave that as your final adjustment.

Hope that helps. Im almost ready to try to build this exact setup to see what im missing

[boldfin]

Originally Posted by Brandon

If you remove the upper link and install the VP panhard link is the axle centered?


YES. That seems to have done the trick. THANKS!





It may not be perfect as its sitting in a different position of the arc it travels due to the lower ride height (ext shock tower). But it should be close.


It's not perfect, but it is close. I think it's off by like 1.5 to 2mm now. Good enough for me.


If it is centered once you are able to mount the panhard link at the axle then how does the driveshaft clearance look? It should be better if I am seeing the current position of the axle correctly.


I've got a ton more driveshaft clearance now.





The driveshaft will still hit the skid slightly at full compression on the passenger side. But that could easily be fixed with a little Dremel work I imagine.




Once everything clears and is mounted correctly other than the upper link, see if there is a spacer you can use to make the upper link clear the chassis and spur cover, leave that as your final adjustment.


That's where I could use some suggestions. As you can see my upper link is now right up against the panhard mount on the axle.
There's no room to get a nut on the end of that screw.





Still getting some interference with the panhard bar and the pumpkin. But I guess I can live with that.





Hope that helps. Im almost ready to try to build this exact setup to see what im missing

Thanks very much for the help. I think we're getting pretty close to working this out. I am really hoping to keep the extended shock towers in the mix. It looks like it will be very low-slung - which is exactly what I was going for.

[boldfin]

Did a little more work on this. Before proceeding with clearancing the skid I figured I'd better install the servo to make sure there wouldn't be any interference there.

Appears the steering link hits the tie bar. I'm not sure if that's really a concern or not. It only happens at full stuff. I'm tempted to give it a try, but I don't know if I'd want the servo horn swinging into the tie bar with 600oz of torque.





So I chickened out and decided to try the standard shock mounts to see if that solved my issues.





But yeah, kinda "nope"...







Barring further input from those more experienced than I, I believe I have come to the point where I shall elect to punt. I really like the design of the VFD trans, but it does appear to require some tweaking to get it to work with TRX-4 axles. If I had more time and inclination, I am sure I could figure it out. But I will probably look into other axle options instead. I'm aware that there are a few choices out there for offset front axles. Not sure which one I will go with just yet.

In the meantime, I haven't given up on running TRX-4 axles under a VS4-10 chassis. I'm just going to start a new project for that. Thanks to Harley's videos, we know a 3 Gear Trans works with TRX-4 axles. So I bought another VS4-10 chassis and all the Vanquish tranny parts to build a 3-Gear Trans - just like in the VS4-10 Origin.

I've got that 3-Gear Trans geared per Harley's suggestions with a 50T Spur/20T Pinion. With a Stock Front Axle and an Underdriven Rear Axle, I should have a pretty decent FDR of 46.21 Front / 52.33 Rear for 12.41% OD.





More on both rigs to come.

[Daycrawler]

Very nice build. I like to see the one off trucks on here. You have made quite a project for yourself.

[Brandon]

Nothing wrong with 2 builds! The VP D44 axles are still my favorite. I haven't seen many VFD equipped builds with the D44's but that will be a direct bolt on for you.

[boldfin]

Originally Posted by Brandon

Nothing wrong with 2 builds! The VP D44 axles are still my favorite. I haven't seen many VFD equipped builds with the D44's but that will be a direct bolt on for you.

Yeah, I may need to change the title of my build thread.

VS4-10 Chassis #1 (with VFD trans - Axles TBD - maybe D44's)

VS4-10 Chassis #2 (with 3-gear Trans & TRX-4 Axles)

[boldfin]

So for now, I'm focusing on VS4-10 Chassis #2 (3 Gear Trans & TRX-4 Axles).

I swapped over the TRX-4 axles and extended shock mounts from Chassis #1 and mounted up the axles using a set of high-clearance links from Hardcore-RC made for the VS4-10 chassis with TRX-4 axles.

















The good news is that with this setup, I am getting all the travel I need, and there are no clearance issues.





Does this look correct? Again - I'm still a noob - but I've never seen axles rocked back like this. My only guess is that may be intended to obtain good pinion angle.

[boldfin]

Well, here is Chassis #2 all done up with the VS4-10 Origin-style 3 gear trans, Hobbywing AXE 2300kv brushless system, and Protek 370TBL servo








Traxxas 3628 Receiver Box bolted on to the slider with screws under the plate up into the mounting ears on the Box.





The AXE 540 motor just barely cleared the rear link mount - and that is with the supplied transmission spacer in place.