EMBUE - E-Maxx Brushless Ultimate Edition FLM/RPM build

[petraeus]

Latest about my build.

So far nothing was broken on this build. I've only replaced a rear plastic driveshaft since it looked a bit worn. And the truck have by now been through a great deal of moderate hard bashing.

Got the 22t Robinson pinion installed. I do find speed more than adequate by now. Using 1/8 scale diffs, a 22/68 gearing seems right to me and the Proline TrencherX's start to balloon a bit at top speed.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1.8333333333333335
Other Ratio: 1
Spur Tooth Count: 68
Pinion Tooth Count: 22
Total Voltage: 16.80
Motor KV: 2200
Tire Diameter (inches): 6.5
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0.006
Spur/Pinion Ratio: 3.09 : 1
Total Ratio: 18.74359 : 1
Tire Circumference (inches): 20.42 inches (518.68 mm)
Rollout: 1.09:1
Total Motor Speed: 36960 RPM
Vehicle Speed: 38.13 mph (61.25 km/h)

That's fast enough to my driving style.


I have replaced the plastic servo horn with a Racers Edge Aluminum Servo Horn Single Arm Futaba/Savox Black. Didn't notice any difference though - at first...

But since I used the outermost hole on the servo horn (for faster action) it might have changed the amp draw of the servo, which then caused some minor glitching that I didn't have earlier. So to be on the safe side, I installed the CC 10A BEC. Problem solved.

FedEx delivery:



I had really been sceptic about Robin @ UE. The lack of communication from his side and the way he wanted money transferred (western union). That concern was totally uncalled for. I'll do business with him again - UE servo saver perhaps?

I planned to use BigBores right from build start. I like the Alu bodies and the quite strong shafts that don't bend easy. But they are 3mm shorter than the Ultrashock, which I don't like

So I could just have stayed with stock Traxxas XXL Ultrashocks. They are longer and actually have slightly bigger bore than the Traxxas Big Bores. But I don't like the plastic bodies, and I don't like the very weak shafts that bends very easy.

So I thought I was going to stay with Big Bores. Installed with 50wt and stock white progressive springs it seemed like a fairly good combo, with springs just a little to the soft side. Thicker oil than 50wt would be to heavy with those stock springs.

The reason to use UE Supershock instead of traxxas BigBores, was mainly since Popoxx went that route in his FLM build.....
He used them in a 8 shock setup, and then I just ordered 2 sets since it seemed like the right thing.
I have seen others using just 4 UE Supershocks on the E-Maxx. But it somehow looks weird to me on an E-Maxx and I couldn't find any cons vs pros of a 4 shock setup.

Got everything put together. Robin recommends using 35-45wt oil on a 8 shock setup, so I used 40wt oil. He also recommended the red springs back and white ones in front.

This is how it looks installed. Unfortunately it's no longer possible to have the Carbon Fiber shocktower braces mounted with these shocks :-( I'll have to find a solution to that issue.















The chassis is starting to show a little wear and tear:






Popoxx used Blacks rear and Blue front. Sorry, no trying to offend any one - but in a 8 shock setup, those springs are way to hard. Sure, it will prevent the truck to bottom out at really high jumps, but it will also totally remove any droop and any good handling when driving on terrain. This is also quite obviuos when you watch one of his youtube videos. Notice how the truck don't drive the terrain, but merely bounces over it. I like a setup where the body is floating over the terrain, and the suspension and tires do their job:





So far I didn't have time to do any test run with the UE Supershocks and tune shocks and suspension geometry.

Red springs back seems too hard for this truck in a 8 shock setup. With shocks mounted on outer A-arm possitions there is only very little droop - it might be better if I mount shock on middle posistion, I'll have to test that.
White springs front seems better. They are just soft enough to give about 1 cm droop. But also here moving mounting possition might help.
40wt oil might also seem a little to thick, but not sure about that yet. I only had 40wt, 45wt, 50wt, 60wt home @the moment.

Dropping the truck at aprrox. less than 100cm height wil not make it bottom out in this setup.
Using the previous BigBore setup would make it bottom out dropped higher than 50 cm!

That's about it for now..

[Popoxx]

You're right about my spring setup, it was totally inappropriate for the playground of the vid. But it wasn't my usual playground, I was on vacation and I hadn't brought the other springs. So the suspension looks horrible on this vid it's obvious... But for big jumps my setup is perfect

[petraeus]

@Popoxx.
Thanks - I was worried that my post sounded like an attack to you - which it wasn't :-)
Your original thread has been great inspiration to me - glad you answered as you did.

Spend some time yesterday evening retuning shock geometry. I moved the top mounting position out, since I had them mounted a bit to much inward.







Now they are using same vertical postion as the RPM shocktowers:
(RPM shocktower is just resting, to show vertical comparison)






But compared to stock Traxxas towers the position is quite narrow:
(Traxxas stock shocktower is just resting, to show vertical comparison)
It's nearly equiliant to the innermost holes.






Not even the UE shocktowers provide a wider position for mounting shocks:
(picture from Popoxx thread)





Relocation of top posistion did soften up the springs a little, but still not enough. I then moved the shock mounting position on the A-arms from the outermost location to middle. That helped some too but supension still seemed a bit to the hard side.

Took it to my normal bash location for some test runs.

On tarmac it was clear that a lot of earlier tail diving during accelleration and nose diving during breaking had decreased. Also body roll had decreased quite some.
On rough terrain the truck was bouncing more than earlier - a bit more than I would like. But it wasn't terrible bad.
Landing jumps was better, but the truck rebounces a little on front end - it did that earlier when using the BigBores too. On bad landings with following cart wheels, the truck felt more solid somehow - more silent.
Clearly it's not bottoming out like earlier, but it still does on some of the higher jumps. Just remember - bottoming out is not all that bad...

More shock tuning are needed - on tarmac it's pretty good already. But on rough offroad it's a little to bouncy.
It could be shockoil to thin, not dampening spring action enough or shock oil to thick not allowing springs to react fast enough. I'm leaning on the oil is a little to thick and might try 35 wt next.

[bentrocker]

You can go wider on those alum shock towers. You just have to get creative. I have my front shocks moved out to where the body posts mount.

[petraeus]

I could be wrong, but those shocks doesn't look like UE Supershocks to me?

Mounted like this the UE Supershocks would be pre-compressed to much.
With the shock pre compressed, there will be less travel available, and there would be a risk that the shock bottoms out way earlier than the truck does - especially on awkward landings. Just a guess..

And actually the UE Supershock have less travel (30.2mm) than the Traxxas Big Bores (32 mm).

[bazookamaxx]

8.0t rears with ue towers

[petraeus]

Ordered Losi LST XXL driveshafts. Reasons?
They look cool and will make my truck even stronger.
Still nothing broken on this build. Nothing! - still amazes me how durable it is.

Coming up...
First video of it running. Nothing special, but will show this truck can handle cartwheels, without breaking.......
Should be on youtube very soon...

[petraeus]

As promised - first video upload of my EMBUE.
Not very good, and a little shaky, since I did the filming myself while driving - not easy to me.
So far I had more than 20 packs of running with this truck - still no damage what so ever. Only body of course

Plenty of power to me on 4S - incredible punch when using ******* ********s 6600 mah, 65-130c.
Not much jumping shoots in this video, since I somehow missed to get the truck in the frame while filming.

[Popoxx]

That's how an E-Maxx must be driven !
Funny involuntary frontflips !
How are the temps after such a session ?

[petraeus]

Thanks - you think those frontflips were involuntary? - there was a lot of practice going on to achieve those
Hopefully next video will involve a lot more jumping. Forgot to bring my temp gun - but motor sure felt warm after 2 packs...

[petraeus]

Link to video

http://youtu.be/rg3tiup2MJs

[M n M]

Today I received the extended diff stub axles FLM sent me.




Compared to the stub axles included in the FLM Ultimate Hybrid Bulk:




Short stub axles are 21.7 mm



Long stub axles are 22.8 mm




Short stubs installed in diff




Long stub axles installed in diff




With the long stub axles it's a perfect fit using stock Traxxas Drive Shaft Axles
But when I took the rear apart, this came to my attention:
The FLM 10900 chassis included rear dogbone was already broken..





This after running 3 sets of 4s lipo. My question is:

Could this be fixed, or do I need a new shaft?
How is that little pin connected to the shaft?
Could it be hammered or drilled out and replaced by maybe a short piece of injector pin?

A little help would be highly appreciated....

Very cool build Petraeus. I've been reading this thread as well as the "What driveshafts will fit these parts" thread by EMAXXBRUSHLESS. I'm seeing now what you guys mean by the Hybrid diff stubs being too short. When I order the FLM UHB is there a part # I should ask for to get the longer axle stubs (22.8mm)?

[petraeus]

Very cool build Petraeus. I've been reading this thread as well as the "What driveshafts will fit these parts" thread by EMAXXBRUSHLESS. I'm seeing now what you guys mean by the Hybrid diff stubs being too short. When I order the FLM UHB is there a part # I should ask for to get the longer axle stubs (22.8mm)?

Thanks. Just ask for the extended stub axles. On my order, I specifically asked to include the long stub axles - but seemed like FLM ignored my request, since they didn't include them. But they very friendly send them to me when asked for second time.
Don't worry if you don't get them. With a good sanding on the stock plastic slider driveshafts, they can fit.

[M n M]

With a good sanding on the stock plastic slider driveshafts, they can fit.

Yeah, see that the thing… I already have and intend on to continue to use the Traxxas steel axle CVDs with the extended drive cups on the RPM True Track kit.

[petraeus]

Then you need the long stub axles.
Do you have plans on going beyond 4s? Hopefully you will be more lucky than others that have tried the Traxxas CVD's on a FLM build. I was just about to go same route, but did A LOT of investigation on this.
Most was not succesfull on running Traxxas CVD's on an FLM E-Maxx using 1/8 scale diffs and RPM Truetracks, not even on 4s.
Loosen slipper clutch and turn down punch control will help to save the CVD's

[M n M]

But currently I'm running the brushed DeWalt 14.4 volt motor. I'm only running LiPo for the longer runtime and just to give it a little more kick. I'm not pushing for speed, just a good all around strong E Maxx. So for me using the FLM UHB becomes a fitment issue.

I was looking at my truck today and I started to think if there is a way to shim the Traxxas axle CVD on the inside of the carrier to kind of push it closer to the diff and keep it inside the cup better? This may not work for everyone but I'm using HPI hex's and the are a little thinner than the Traxxas hex's. I put a washer between the hex and the carrier just to take up the play. That 1/16 of an inch moved to the inside may be just enough to keep it all together.

I'm sure this is only making sense to me.

[Wildman4910]

This is how it looks installed. Unfortunately it's no longer possible to have the Carbon Fiber shocktower braces mounted with these shocks :-( I'll have to find a solution to that issue.

Since your not using a wing why not put the wing mount holes to use to hold some aluminum upright's that could be used to bolt the Carbon Fiber tower braces to?

Sweat build Petraeus!

---

MnM cut some of the threads off the end of the pillow balls so you can crew them in farther, this will move the carrier & CVD in so the CVD sits deeper into the Dr cup.

[M n M]

MnM cut some of the threads off the end of the pillow balls so you can crew them in farther, this will move the carrier & CVD in so the CVD sits deeper into the Dr cup.

Wow... That's an awesome idea!! I never would have thought of that. THANKS!!

[bentrocker]

I have done this on my e-slayer to narrow the rear track. Works well.

[petraeus]

Thanks for the idea - but unfortunately is to late. After a good day at the track, I noticed this:

FLM rear shocktower











Simply too soft
Exactly why I wanted to use the Carbon Fiber shocktower braces.


Everything else was good. Oh, exept FLM alu skidplates. They are bending too (as I was already told by others)

But I'm still not sure about those UE supershocks. Had my E-Maxx on a 1/5 scale astro turf track today. Red springs back still feels to hard. I might go back to the Big Bores again - I'm in doubt. Could be wrong again, but maybe they just fit the E-maxx better? Seems like a 8 shock UE supershock are a litte overkill.....

Now I'll have to use my RPM shocktowers a little again. I just don't like how soft they are...
Maybe I should order some UE shocktowers

@Popoxx - would you recommend them over the FLM shocktowers?

[bentrocker]

What the heck did you hit to do that? Skate park ?

[M n M]

Ouch Petraeus, that hurts.

A couple of guys are recommending the UE Knucklehead towers on this thread. But it seems that you need to have round body posts.

The Great Aluminum Shock Tower Debate

[petraeus]

What the heck did you hit to do that? Skate park ?

I never did and never will do skateparks. 70% I bash like in my first video - 30% I "race" on a 1/5 scale astro track.
Don't know how it had happened - must somehow have been on the track today.

[Popoxx]

@Popoxx - would you recommend them over the FLM shocktowers?

YES !! I quickly bent my FLM shock towers as well. UE ones are stronger (7075-T6 alu), thinner, and look better.

[bentrocker]

Wow just checked out the price for the ue shock towers. Take the shine off a hundred pretty fast.

[petraeus]

Wow just checked out the price for the ue shock towers. Take the shine off a hundred pretty fast.

On sale. Only USD 35$ - and I'm guessing that includes 2 pieces.

[bentrocker]

I am pretty sure that is for one . They come in pairs with the kits.But if you are right i may pick up a set.

[Popoxx]

On sale. Only USD 35$ - and I'm guessing that includes 2 pieces.

You're right. $35 for 2 shock towers with screws, shock standoffs, body post supports and plastic body posts (to be drill and cut to the appropriate size). Great deal !

[petraeus]

For a short time I considered using my RPM Shocktowers again. Took of the FLM Towers and UE Shocks, and then mounted the RPM towers and Bigbore shocks.
But no - I just don't like all that flex in the RPM towers. That can't be good for anything else than break-preventage. I don't know if I'm right about this, but I always felt that all that flex caused bend shockshafts - but I could be wrong. Also the RPM body post are worn down - to replace those, I would have to buy new RPM shocktowers, since the RPM body posts don't sell seperate!

so I've hammered the FLM Shocktower back to normal.
But I'm not sure which setup I like better. Traxxas Big Bores or UE Supershocks

Somehow I find the 8 x UE shock setup to much. Remember I used 40wt all around, white springs front, red springs back. This setup is just too stiff for my E-Maxx. The white springs front might be ok - but red springs back are too hard.
If you run on tarmac or very smooth track and taking high jumps, this setup could (just) work. I know some would like a shock setup to prevent the E-Maxx to bottom out at really high jumps - but to my believe and due the design of the E-Maxx, it's not possible to prevent this, if you at the same time want a suspension that works nice in off-road conditions.

If you want to use UE Supershocks, my guess would be it'll be best to use a 4 shock setup. Just like described here:

http://traxxas.com/forums/showthread...=1#post3417961

Edit - all my 3 trucks use the same shocks. The only difference are the shock oil weight and spring rates.

Supermax (10.2 lbs rtr; fuel etc) - 4 Racerx shocks, 50 wt rear, 50 wt front, red UE spring front, blue UE spring rear

Predator maxx (9.75 lbs rtr; fuel etc) - 4 Racerx shocks, 50 wt rear, 45 wt front, white UE spring front, red UE spring rear

Emaxx brushless (11.7 lbs rtr; lipo etc) - 4 Racerx shocks, 50 wt rear, 50 wt front, red UE spring front, black UE spring rear


UE Supershocks minor issues;
The springs provided are a little to small in diameter, causing the springs to slightly rub against the threaded shock body.
They actually have less travel compared to the Big Bores.
They don't feel just as smooth as the bigbores.
Due their length they would have to be mounted very high at the shocktowers. This causes extra stress on the towers, which I think was why my FLM rear tower bend. And comparing the FLM to the UE shocktower, it seems like the shocks would need to precompressed when used with UE towers?

Traxxas Big Bores minor isues:
They're a little shorter than stock Ultra shocks. If used with stock- or RPM towers they should be extended to 110mm, by Increasing the length by threading the rod end out to expose a couple of threads.
If used with FLM or UE towers they could just be re-positioned.
Stock white progressive springs are just a little to soft.

I'll have to do a little more testing if I'm going for 8 x Big Bores or 4 x UE Supershocks. Decisions, decisions.....

[bentrocker]

Was it only your rear shock tower that was bent? Witch way did it bend ? Was it bent towards the front of the truck or was it bent back away from the front of the truck?

[petraeus]

Was it only your rear shock tower that was bent? Witch way did it bend ? Was it bent towards the front of the truck or was it bent back away from the front of the truck?

Only rear tower was bent - towards the front. If CF braces had been installed, I'm pretty sure it hadn't bent at all.
Today I quickly compared (no driving) the stiffness of a 4 x UE setup to a 8 x Traxxas Bigbore setup.
With 2x UE shocks/ black springs back, the truck felt very close to same stiffness as with 4x bigbores/ white progressives.
Really hard to tell the difference. Think I'm going to run the bigbore setup a couple of times. Might order a complete Integy E-Maxx spring set for further testing.

[bentrocker]

If the shock tower was bent towards to the front that would tell me that it happened when you landed upside down off a jump.
Don't think any shock combo is going to help that. I think what has helped me from doing that to my e-maxx is the rear wing. The wing absorbs the shock from the upside down landings.

[petraeus]

You're most likely correct

Oh - forgot..
These were in the mailbox today - only 1 week from US to Denmark:

Losi LST XXL CVD driveshafts



Will go to my LHS asap to buy bearings.

[bentrocker]

You are going to like those cvds.

[EmaxxChris]

I just got my FLM ultimate hybrid bulks. They came with the longer stubs. Got the front diff set. Took 8, 13x0.2mm shims for the front, didn't order enough for the rear. So it will have to wait. Amazing how much stronger they feel shimmed. Should have done that to the stock diffs. 10k front, 5k rear. Thanks for this thread, helped me out!! Nice to have a diff with no slop at all!

[Suteki]

Out of curiousity, what brand are you guys using for diff oils? Knowing how greatly wt changes from one brand to the next, I am curious as to how close many people are as far as what they are using. I'll end up using Losi diff oils, so I was curious as to recommended wt from Losi.

Also, 13 shims? Really that is heaps, was it that loose in there?

[EmaxxChris]

Out of curiousity, what brand are you guys using for diff oils? Knowing how greatly wt changes from one brand to the next, I am curious as to how close many people are as far as what they are using. I'll end up using Losi diff oils, so I was curious as to recommended wt from Losi.

Also, 13 shims? Really that is heaps, was it that loose in there?

Mine took 8 shims, Losi, 13mm differential shims that are 0.2mm thick, comes 4 in a pack, and I only bought 3 packs, so I need another one. Basically had about 1.6mm of play side to side in the diff. Hopefully it'll be here today or tomorrow. Stormer only had Imax, I believe that's the name of the diff oils in stock.

The front diff and bulk is completely setup, spins nice and smooth, the rear however is "tighter". The cup/spider gears seem to be harder to turn than the front one. I'm going to loosen the screws a bit and see if I need to use a thicker gasket. I just used 2 of the thinner ones. Any ideas on this would be appreciated!

[bazookamaxx]

take it apart and start over, no shims, then go from there. if its too tight on 1 and took 13 shims on another you may be no offense doing it wrong

[EmaxxChris]

take it apart and start over, no shims, then go from there. if its too tight on 1 and took 13 shims on another you may be no offense doing it wrong

I've only got one of the hybrid bulks together, the front one. The cup/ring gear required no shims, on either diff. When getting rid of the side to side motion of the front diff within the bulkhead case, it required 4 shims where you shim. The outdrives of the rear diff is "tight" compared to the front. It's not mounted in the bulkhead case. Guess I'll just have to take it apart and see. Thought I might need to add another gasket to space the ring gear from the cup. I might just post a new thread if that doesn't work, so I don't hijack and clutter up this good one!

[petraeus]

The outdrives of the rear diff is "tight" compared to the front. It's not mounted in the bulkhead case. Guess I'll just have to take it apart and see. Thought I might need to add another gasket to space the ring gear from the cup.

Just take only the diff apart:



and check all is good. A thicker gasket might help.


Notice the DIFF-erence
Traxxas diff compared to Casterracing 1/8 diff:








Notice the wear on the the Traxxas diff - and that's by running 4s lipo only (well, and very little 5s)
But I think the damage is mostly caused by the TrencherX tires - to much bite and stress caused by these big tires..