Kagama Horatio's Kraton 6S EXB V6 Build

[Horatio]

I agree that the diffs are Arrma’s biggest weakness, but going lightweight with modest size/weight tires will help significantly. I do like Arrma’s steering setup better in general, shocks definitely. If it weren’t for the extreme offset of the center diff TC easily wins the drivetrain durability contest. Plastics quality goes to Arrma for me, but neither is very impressive compared to TRX. Best plastics I’ve come across, just short of race kits. Arrma and TC plastics wear too quickly for my liking. I don’t experience much breakage however.
The Kraton, or at least v5 that I have doesn’t handle as well as my XTR, not even close. The v5 Talion is much closer, maybe better than XTR, not sure.
But yeah, I’m definitely tuned in brother!

Cheers buddy!

It's been a while - busy wrapped up in work, racing and family stuff. I hope you and yours are all good.

So far, the more I take this rig to bits, the more I like some of the details. The wire clamping post, gaskets on the front and rear transmission housings, the shocks, the brace mounts, layout and the quality of the housings.

And by damn! This mofo was not coming apart without a fight. All the screws going into metal needed heat. A lot of heat. Plus - plas gas dismantling fluid. And a hammer. It was extremely taxing to get this rig apart without damaging everything around it.

DIY gasket for the front - half of it was gone.

But either way you slice it - this is a light weight chassis.

So far, so good.

 

[Horatio]

XRT is awesome.!!! So is the Xmaxx I still have Arrma’s (built, not boxed) their best truck, PERIOD, is the Mojave.!!
The Mojo is the only truck I didn’t build out of parts, was lucky enough to pick up two OG EXB rollers back in the day

I truly hope @Horatio you can make a Kraton into something good.!!
And if you can’t, you nearly have all the parts to make a Talion, Arrma’s second best truck EVER….

Cheers buddy!

I'm hoping so too. It's definitely going to be a different flavour. I hope I don't keep breaking it on 6S.

The Kronos XTR has been beast! Never really breaks anything. (Except the rear wing).

I'm really enjoying the build and Scorched stuff is literally the Rolls Royce of aftermarket parts. Bonehead too are similarly excellent.

If the Kraton turns out to be a turd, I'll be very interested trying Talion mode - let's see what happens.

 

[KnowAir]

Cheers buddy!

It's been a while - busy wrapped up in work, racing and family stuff. I hope you and yours are all good.

So far, the more I take this rig to bits, the more I like some of the details. The wire clamping post, gaskets on the front and rear transmission housings, the shocks, the brace mounts, layout and the quality of the housings.

And by damn! This mofo was not coming apart without a fight. All the screws going into metal needed heat. A lot of heat. Plus - plas gas dismantling fluid. And a hammer. It was extremely taxing to get this rig apart without damaging everything around it.


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DIY gasket for the front - half of it was gone.

But either way you slice it - this is a light weight chassis.

So far, so good.

All good over hear buddy!
They have indeed changed some things from v5 to 6, I don't think Arrma ever used gaskets prior to v6 to seal the gearbox to the chassis. Perhaps because the bulkheads are alloy?

 

[KnowAir]

Traxxas xrt tire is 100mm wide just need to modify the hex to fit arrma or check out brp tires they do some 3” & 4” wide but ain’t cheap

https://taylorrc.co.uk/collections/1-5th-scale-wheels-tyres

I have the XRT tires, I use them occasionally on my Xmaxx. They work pretty well when the clay is wet and tacky, but once things dry out they’re greasy. Compound is too hard.
They seem to hold up to the weight of a TRX but I don’t think they’re up to task for the Arrma, wheels are super thin. I’ve broken the TRX wheels on my Xmaxx before. I run some Rovan D5 tires/wheels on the Xmaxx with good results, tried them on the K8 and broke a wheel hub first day using them.. Makes me wonder how they hold up on a true1/5 like the D5.
I am familiar with Taylor RC as well as Cardinal Racing. The 100251x tires/wheels made for the MCD W5 truck look the most promising but they don’t publish the width specs. At $100 a pair I’m afraid to buy them only to have yet another set of tires I don’t use, LOL. Got cabinets full of them already.

 

[KnowAir]

Cheers buddy!

I'm hoping so too. It's definitely going to be a different flavour. I hope I don't keep breaking it on 6S.

The Kronos XTR has been beast! Never really breaks anything. (Except the rear wing).

I'm really enjoying the build and Scorched stuff is literally the Rolls Royce of aftermarket parts. Bonehead too are similarly excellent.

If the Kraton turns out to be a turd, I'll be very interested trying Talion mode - let's see what happens.

Hey, good guys are always in demand, which is why you’re so busy!

 

[Horatio]

All good over hear buddy!
They have indeed changed some things from v5 to 6, I don't think Arrma ever used gaskets prior to v6 to seal the gearbox to the chassis. Perhaps because the bulkheads are alloy?

I think that must be it. It's a nice touch and provided the diffs don't self destruct before hand, the CNC housings should keep everything in just the right place.

I'll be checking the shimming.

Well after an early finish with work, gardening, house work and family stuff, I'm happy to have got to this stage without too much trouble.

Hubs next, then electronics......

 

[Horatio]

In the meantime, here's a great video put together by Chris with a C and Grum RC, friends of SWRCCC.

Chris took Grum to Robbie Bain's bash event, held at Heatherton World of Activities, near Tenby, West Wales.

Robbie has recently been racing vintage at SWRCCC and hosts a very impressive (and incredibly dusty) bash fest!

Nice FPV footage from a DJI Avata drone too - most impressive!

 

[Horatio]

352g - not too heavy considering the size of the chassis - compares quite similar to the XTR chassis...which is about 360g. Plus the plastic and braces here, equalling 546g.

So, the XTR in off road mode is:

Minus the running battery - 5425g.

So, here's where we're at with the Kraton today.

So, will the EXB be higher or lower than 5425g, before a 6S battery is fitted?

It's looking pretty sweet so far and I've thoroughly enjoyed getting it sorted. Should be ready in time for the bank holiday Monday here in the UK.

I intend to do some back to back runs with the GPS installed, off road, and see how each performs.

As a side note - I have seriously fallen for this incredible paint job:

 

[Partydaz]

Hope ya got a gazillion fans to keep that thing cool! On my forecast its got 31°C for monday .

 

[Horatio]

Yes, it's getting toasty! That being said, it's a little cloudier out West. The mid 30°C temps are in the South East.

Apparently it hit 32.8°C in the UK in May - back in 1944!

Looks like the record is about to be broken.

 

[BashingBrian]

So, will the EXB be higher or lower than 5425g, before a 6S battery is fitted?

Heavier..!!

 

[Horatio]

Heavier..!!

But can you guess how much heavier?

Closest to actual gets bragging rights!

 

[Horatio]

Okay, so I was expecting the Kraton EXB to be heavier, but....

XTR - minus the battery, in off road configuration. 5425g

EXB without battery....

5733g

A difference of 308g - even with an all Carbon chassis and chassis braces.

 

[Nelson.81]

It has metal bulkheads kronos doesn't, shock towers too maybe needs more carbon pieces lol could pull that front bumper of too. How much difference is there between bodyshells & tires too

 

[Horatio]

It has metal bulkheads kronos doesn't, shock towers too maybe needs more carbon pieces lol could pull that front bumper of too. How much difference is there between bodyshells & tires too

Clipless body is heavy.

Alloy transmission cases are heavier than composite.

Alloy shock towers are heavier than the M2C Carbon Kagama towers used on my XTR.

Mounted copperheads weigh about 355g per wheel.

Mounted XTR tyre (which looks like the same tyre Kagama use) is 315g on Kronos wheels.

It all adds weight.

I could easily live without the clipless body system - it puts weight up high on the truck too.

Bumper also - I could live without. There's no real need for one unless you often lawn dart into stuff.

So, onto the driving....

 

[Horatio]

So it's time for a very quick first impressions shootout.

The EXB is geared lower - for more punch. The motor seems very eager - much like the Kuron - on this gearing it wants to wheelie, thus requires very careful throttle! ESC is very punchy.

Steering - servo isn't great, but it does it's best. EPAs set, I noticed the rig was more readily turning left than right. It seems mechanical, so I'm figuring it out. Everything looks good, but I might lose the vibration grommets for a more direct servo feel. And change the servo!

Handling. The EXB is sprung more firmly and wants to sit higher, even with less preload. The truck is surprisingly responsive - but it doesn't rotate with the same authority as the Kronos.

The Kronos rolls more quietly - even with the sub optimal centre front driveline angle.

Both trucks jump nicely, but again, the XTR is more responsive in the air.

Plastics - yep! Arrma plastics on the radio tray and other parts feel better to me - especially the wing. Upper front arms on the EXB are equally prone to slop as the XTR.

Track width on the trucks appear identical - but the EXB has longer suspension arms and longer travel shocks. For extreme jumps - the EXB has to be better equipped - but - it does so carrying more weight. Much more weight out of the box.

Spektrum IC5 - useful only if you run Spektrum smart batteries. So - out they come.

I'm not sure if I was driving too hard, but I browned out my RX with the Spectrum Steering servo. Something odd was going on. A freshly charged OPS Graphene battery has plenty in the tank and ordinarily wouldn't have any issue supplying the servo with more than what it needs. I can't think why the servo would have been drawing too much off the Firma ESC. I set the EPA etc. Bizarre. I think it only has a 4A continuous BEC.

But, it's early days, running a rebuilt RTR which has evidently been run once in wet conditions and then left for months in a box.

That all being said - the main issue with this EXB rig is the RTR electronics. Directly compared to the 2021 XTR, you'd think that a 2026 V6 EXB would be packing something that would worry the competition! Nope.

 

[Horatio]

Stuff I really like about the EXB:

• Plastics
• Clamp for wires
• Radio box
• Chassis layout
• Drive angles
• Vast aftermarket upgrades
• Shocks
• Long arm suspension
• Transponder mount with rubber clip
• Battery tray
• Super secure straps
• Punchy motor
• Rubber compound with Copperhead Dboots
• Build quality, fit/finish.

Stuff I really dislike about the EXB:

• Excessive weight
• Clipless body
• Spektrum in general
• S665 Servo is a struggle on 6v 15kg .19/60°
• Locked into 6V bec
• 4A Bec WTAF?
• IC5 connectors are pointless

So clearly, there's room for improvement - and all the issues will be remedied asap.

Both these rigs are going to get a lot of use this year! Different flavours - sure, but the EXB has much more potential yet.

I think Bashing Brian makes a valid point - out of the box, I too would expect more. In that regard, Corally really do offer much more bang for your buck. Especially with the Kagama and all the aftermarket support it has.

 

[Nelson.81]

What weight did you put in shocks I made mistake of going too light a weight on oil originally , out the box they run 1300 cst.

 

[Horatio]

What weight did you put in shocks I made mistake of going too light a weight on oil originally , out the box they run 1300 cst.

I've no idea what weight oil is in the shocks. If I had to guess:

Front: 100 wt

Rear: 90 wt

Which is very, very thick.

 

[Horatio]

Horatio goes to the skate park!! Is a sentence I never thought I'd say. But to hell with it. YOLO.

10 minutes of this - and my rig was going thermal. To be fair, it's very, very hot today and I wasn't taking it easy. Nothing broke though.

So it was jumps and wheelies all over St David's Park - or Parc Dewi Sant in Welsh.

Then I took my XTR carefully over to - the Velodrome!

So, let's go for a spin!

This was on the Velodrome! In off road mode, on my lowest gearing - but using the 46t spur. 13/46. Holy smokes.

Technical issues have occurred with my DJI camera - it too went thermal, which now means my forward facing screen with the SD card is now a paperweight.

I'm attempting to retrieve the footage from the internal storage onto my SSD.

Once I've done that, I'll up a 4K video. Suffice to say that the rebuilt XTR is doing what it does best - hooning around, tyres lit up - jumping, wheelieing and generally being bonkers.

It works on Sand, gravel, grass, concrete, tarmac - simply put, today I tested it over every type of surface you are ever likely to drive an RC car on. It just hooks up and goes!

Total respect to the XTR.

Once my chassis protector and glitch buster has arrived - the EXB will be attempting the same. Not sure I'm happy attempting 60mph running until the ESC can cope with the servo it was supplied with.

Big boots to fill - that's all I'm going to say on the matter.