Traxxas Rustler with working 2 speed

[Armysolo]

I've seen this asked a couple of times so I thought I'd share how I put a 2 speed in my Traxxas Rustler.

Some background:
This was my first nitro RC. I've been working on cars all my life but my background is IT and Engineering. I got the stadium truck from my dad. He bought it probably close to 15 years ago. He did the break in and started tuning the carb and the throttle hung and it met a curb. He put it in a box and that's where it laid until I asked him about it this past March. He gave me everything he had for it. When he hit the curb he broke the upper chassis deck which cost me $10 from our local RC shop. While I was there I decided to do the power up program and swap the old receiver and transmitter with a new TQI one and add a full waterproof receiver box.

It took me a couple of hors of cleaning out the carb with brake cleaner and q tips before it'd slide like butter.
Next was the motor. I knew it was seized because I couldn't move it by hand at all. I took the glow plug out and added a couple of drops of 5w30 in the head. I 3d printed an adapter for the one way bearing with a 17mm hex on it so I could spin the motor with a ratchet. I heated up the block with a heat gun and tried to wiggle the crank back and forth. I sprayed some WD40 to try and break down the rust. very slowly did it start to move until eventually I heard a metallic click and the crank moved freely. I used the ratchet until my hand got tired and put the 17mm on my 1/4" impact. Added some more 5w30 and spun the motor very slowly. After a couple of minutes I'd spin faster and faster until the impact was full speed. Slapped it all back together and the damn thing ran.

I bought a HPI Savage X. The Rustler took the back seat for a while but I did swap the 2.5r out for another 2.5r using the power up program. But I decided to do something completely ridiculous with my rustler. First I decided to put a HPI 4.6 big block in it. Nowhere near practical but honestly I wanted to see if it'd work. I had to cut a custom carbon fiber chassis plate. I did this in my backyard with a dremel, a drill press and the original chassis plate as a template. The aluminum parts in the picture are from Integy and are actually from a Rustler VXL.

I took the 4.6 out and put it in my Revo and slapped my Dynamite 19 back in the rustler but I wanted more out of it.

My local RC shop had 1 OS 11k 18TM carb still in stock, yes they still had 1. I didn't need it but I knew how hard they were to find because of COVID and they were backordered I decided to buy it. I took the 2.5r that was swapped out with the power up program and dropped in a 3.3 crank with the OS 11K carb. Doing that woke up the motor something fierce.

After that I decided to think about what I could do to take this build over the top. I started looking for a Jato 2 speed. I found a brand new one off Ebay for $100. Along with the 2 speed I started thinking what else I'd need to make it work with the Rustler. I knew I'd need a custom chassis plate so it ended up making things easier. I bought an engine mount, throttle/brake linkages, brake parts, shock tower, control arms, drive shafts, caster blocks, suspension links, wheelie bar and battery box for a Jato. Basically everything from the motor mount and back is from a Jato. I also decided to drop in the Hot Racing Jato 2 speed steel gear set.

The wing is off a Losi 8ight I mounted to the shock tower with a custom cut carbon fiber plate

I'm using RPM control arms, caster blocks and steering blocks off a 2wd electric slash.
I did a MIP 12mm to 17mm hex conversion from a Rustler, but I did need smaller front axles so I used some from a bandit.
Proline shocks all the way around.
I've got the front brackets for the sway bars but I haven't found a way to stabilize it yet so that's taken the backseat for now and I removed the sway bars.

This weekend I will be fitting a Jato body on it it getting rid of the magnet mounts. Last night I got it to hit 45 according to the GPS sensor but I know the Jato is rated for 65+. I've got a 20T clutch bell and a 54T spur gear. Even though it has a 2.5r in it, it should be able to come close to that because from what I've seen the main difference between the 3.3 and 2.5 is the crank. The piston and connecting rod are the same so it's basically a 3.3 in a 2.5 block. Well that's what I've seen/heard and I could be completely wrong.

 

[gandalfnz]

Wow, so much experimenting.
Good on you!

Would be nice to see a vid of the builds running.

 

[Chubaka]

Welcome aboard. Looks like a handful with that 4.6. How do you like the dynamite engine. I have atleast 7 traxxas nitros I'm working on getting running again and am considering one. I'm already planning to get the 11k carb for my 3.3 as the losi 3.4 is hard to find.

One of these days I'm gonna finish my nitro slash with a .15 and jato 2 speed. Good to know RR has steel gears

The og Jato 2.5 hit 65 I think on a 2.5 with I believe 33%. Assuming they used a slightly downhill grade or did some chassis work you should be able to do atleast 60. Did you remember to throw the Jato stickers on.

 

[gandalfnz]

Welcome aboard. Looks like a handful with that 4.6. How do you like the dynamite engine. I have atleast 7 traxxas nitros I'm working on getting running again and am considering one. I'm already planning to get the 11k carb for my 3.3 as the losi 3.4 is hard to find.

One of these days I'm gonna finish my nitro slash with a .15 and jato 2 speed. Good to know RR has steel gears

The og Jato 2.5 hit 65 I think on a 2.5 with I believe 33%. Assuming they used a slightly downhill grade or did some chassis work you should be able to do atleast 60. Did you remember to throw the Jato stickers on.

Even if you could, I wouldn't bother with losi carb. I did some research on this a while back, and from what I remember its also made from composite material, same as traxxas carbs.
Also, from all the videos I have seen, the same problem remains, very hard to tune idle.
Not sure why some praise it, when 11k is superior in every way.
Don't waste your money, just get the OS.
I got two, one in my Nitro Slash and on 3.3 it runs real well.
The other one (Jato), I haven't tested yet.

 

[Armysolo]

Even if you could, I wouldn't bother with losi carb. I did some research on this a while back, and from what I remember its also made from composite material, same as traxxas carbs.
Also, from all the videos I have seen, the same problem remains, very hard to tune idle.
Not sure why some praise it, when 11k is superior in every way.
Don't waste your money, just get the OS.
I got two, one in my Nitro Slash and on 3.3 it runs real well.
The other one (Jato), I haven't tested yet.

The Traxxas carbs can be very hard to tune. I took apart the 2.5r to check compression and there was very little left even though it had maybe a gallon on the motor. Just goes to show how bad the Traxxas break in method is. Which is unfortunate because I kept having issues with the 2.5r and that's why I bought the Dynamite 19. But now the dynamite 19 backplate has a lot of slop where the starter shaft goes through so it's sucking in a ton of air. I bought a SH18 backplate I'm waiting for.

I bought a new piston and sleeve for the 2.5r and did the Adam Drake break in method. I built an engine run plate for it and let it idle for a tank, let it cool and repeat about 6 times.

 

[Armysolo]

Build update:

The HPI F4.6 was only planned to be temporary because I was going to put it into my Revo big block conversion. Once all the parts came in for that the 2 speed Rustler got pushed aside. Now that the Revo is running like a beast I got back to working on the 2 speed Rustler.

I decided to again do something ridiculously awesome and stupid and buy a Dynamite 28 Big Red and make that fit. RCRenew sells Jato big block engine mounts on Ebay. I went with a HPI truggy fuel tank because they seem to seal better than the Traxxas ones. Using my Dynamite mid/high pipe I put it on the break in plate and let it idle heat cycling for 6 tanks.

One thing I absolutely hate about these engines is the pull start is a POS. I've went through 2 pull starts in under a week and 1 of them had about 20 pulls on them. I wanted to use a roto start but because of the design of the starter shaft, the hex sticks out of the back plate about 3-4mm. The shaft would walk back in forth inside the roto start causing it to suck in air.

I got a LRP Z.28R back plate(38132) because it had a larger starter shaft hex and it fit perfectly. There was still some play in the roto start housing so I cut a hex out of carbon fiber to use as a spacer to keep the starter shaft flush against the back plate.

I had to cut a new carbon fiber chassis plate and upper deck to account for the new fuel tank dimensions. First the first couple of shake down runs I had to put the Dynamite pipe and header on until I could find a L shaped header. I was running it without a body and at most 1/4 throttle anyway.

New L shaped header was delivered but I couldn't run the pipe out the side to the front like I originally wanted. The pipe was too long and it'd hit the left front tire.
Some shakedown runs done with the new body on. Had to cut out a lot to make room for the pipe and that big ass heatsink. It'd run and drive right but the pipe would rub against the tire even with a ton of preload on the springs.

So as it currently sits not a bad weekend project. I have some GTR shocks and springs on order. I'm using red proline springs with 60w oil and the rear end is still sagging so hopefully the GTRs will help bring it back up. I'll also be cutting another plate out of 4mm CF. I need to increase the wheelbase otherwise I'm going to be melting tires.

 

[Armysolo]

Build update 2:

I knew I had to do something with the the exhaust it. If I kept it the way it was, I'd melt the rear tire. If I flipped it forward it'd hit the front tire. I didn't want to use the original U shaped header because I'd have to cut way too much out of the body and it'd be almost impossible to adjust the idle screw.

I used the original rustler chassis plate as a template to keep the plate the same size. This is one of the first chassis plates I did a couple of months ago. The following is kind of a DIY on how I cut my CF plates.

Safety Tips:
When cutting CF it can be hazardous and irritant. I cut all my plates outside. I wear nitrile gloves and have a shop vac going at all times along the cutting path to collect as much CF dust as possible. When I have to get really close while cutting I wear safety glasses. Yes it's uncomfortable and wearing gloves outside gets hot but you NEED to take precautions when cutting CF.

I used 3m 2 sided tape to stick the plate to the carbon fiber. Sharpie fine or extra fine paint markers are amazing for making markups on the plate. Silver yellow or gold work the best but any dust on the plate will clog the nozzles on the extra fine markers. When I did my savage plates I marked the crap out of the plate.

Used my dremel with a diamond wheel and cut around the plate leaving a few mm extra. Once the general shape was cut out I started to cut the pilot holes. I did it in this order because I didn't want to risk the plate shifting while sanding to the final shape messing up where the screw holes are supposed to be.

Drilling through CF can be tough. Your biggest enemy is heat and how sharp the drill bit is. I use my drill press that can run max 3800 RPMs with 3mm and 4mm jobber bits to start the hole but not cut all the way through yet. I basically mark the size of the drill bit because when drilling through CF if there's nothing on the other side of the plate, when you punch through the hole will splinter. After I use a jobber bit I throw it away.

Once the pilot holes were done I used my Dremel router shaping table with a sanding drum. You can use a sharpie paint marker to trace around all the edges, marking both the CF and the chassis plate. When you have the color on the edge of the chassis plate, if you get too close with the sanding disk it'll rub off the paint, that's how you know that area is done. To cut the holes in the center for the transmission and flywheel I drilled a 4mm couple pilot holes and used my router shaping table with CNC carbide bits to cut the shape out.

Once the general shape is ready pop the chassis plate off and drill through the rest of the plate

I like to use masonry bits. They have a harder tip then normal bits do. You can use the "jobber" bits but be prepared because you will go through a lot of them. I haven't found masonry bits in metric so for like a 3mm hole I have to use 1/8 which actually cuts the whole at about 3.3mm. Normal tolerances for a 3mm screw hole is between 3 and 3.3mm anyway. You just have to be careful when using a 1/8mm bit with the pilot mark you made earlier. Make sure it's centered and the bit goes in straight. To prevent excessive heat build up I'll start drilling one hole about 1mm, then move to another hole and continue until you've cut all the way through. Having a piece of wood or scrap CF behind the plate your drilling will help prevent the back side from splintering.

And here you can see the finished product:

But back to the 2 speed build:
I decided to cut a new CF plate lengthening it about 20mm. I basically stretched the front of the chassis plate where the bulk head and the steering bell crank mounts are.

Putting everything back together:

I still want to replace the Proline shocks with GTRs. They were delivered yesterday but I'm still waiting on the springs.

 

[Armysolo]

Build update #3

Well I've made a lot of progress on my Rustler/Jato build but I decided to throw myself a curveball. I never could get her up to top speed because I couldn't be as aggressive as I would with my Savage or Revo. So far I've hit 54 confirmed with the Traxxas GPS sensor and the bike GPS sensor on the wing. Because of how fast this thing is and how light it is but most of the weight being in the rear, I needed a lot of runoff space otherwise I'd have to lock up the brakes and risk losing control or decide to tempt fate with a curb.

I decided to figure out a way to add front brakes. Granted there were probably better and more efficient ways to do this but with out a CNC it limited what I could because I didn't want to 3d print anything for it.

I found some 1/10 calipers and disc brakes from a "Capo Jeep" on Aliexpress. The rotor is sitting on a 12mmx7mm wheel hex on the differential input shaft.

I swapped the original front end with a differential, CV shafts, control arms, shock tower and bumper from a rustler VXL. There's a 2nd break push rod that that goes from the throttle servo to a bell crank. When the Jato breaks it moves the throttle servo spins the servo arm forward, that will push the pushrod towards the front of the car, spinning the bell crank counter clockwise pulling the brake cable that attaches to the front caliper, and wham bam Bob's your uncle(Mythbusters reference).

All in all it works way better than I expected. I know I will have to redo the chassis plate. I had to lengthen it again to make room for the Hot Racing steering bell crank and to clear the brake disc. The wheelbase is 1.5 - 2" longer so none of the bodies will fit correctly. I'm going to be getting a different steering bellcrank so the steering servo will sit inside the CF plates going width wise of the car. That should allow me enough clearance to shorten the wheelbase by at least an inch.

 

[Chubaka]

I can't have a front brake set up. I'll be power braking it every chance I get. Truly amazing on your part.

 

[theeo928]

Great thread. Do the Jato big block mounts fit on the original Rustler chassis?

 

[luke66]

Build update #3

Well I've made a lot of progress on my Rustler/Jato build but I decided to throw myself a curveball. I never could get her up to top speed because I couldn't be as aggressive as I would with my Savage or Revo. So far I've hit 54 confirmed with the Traxxas GPS sensor and the bike GPS sensor on the wing. Because of how fast this thing is and how light it is but most of the weight being in the rear, I needed a lot of runoff space otherwise I'd have to lock up the brakes and risk losing control or decide to tempt fate with a curb.

I decided to figure out a way to add front brakes. Granted there were probably better and more efficient ways to do this but with out a CNC it limited what I could because I didn't want to 3d print anything for it.

I found some 1/10 calipers and disc brakes from a "Capo Jeep" on Aliexpress. The rotor is sitting on a 12mmx7mm wheel hex on the differential input shaft.
View attachment 173365
I swapped the original front end with a differential, CV shafts, control arms, shock tower and bumper from a rustler VXL. There's a 2nd break push rod that that goes from the throttle servo to a bell crank. When the Jato breaks it moves the throttle servo spins the servo arm forward, that will push the pushrod towards the front of the car, spinning the bell crank counter clockwise pulling the brake cable that attaches to the front caliper, and wham bam Bob's your uncle(Mythbusters reference).

All in all it works way better than I expected. I know I will have to redo the chassis plate. I had to lengthen it again to make room for the Hot Racing steering bell crank and to clear the brake disc. The wheelbase is 1.5 - 2" longer so none of the bodies will fit correctly. I'm going to be getting a different steering bellcrank so the steering servo will sit inside the CF plates going width wise of the car. That should allow me enough clearance to shorten the wheelbase by at least an inch.
View attachment 173366View attachment 173367

YO! front breaks on a traxxas 2wd? looks way cool! how did you do the wheelie bar? I've got a Mid-motor rustler going but i can't for the life of me hack up a wheelie bar.

 

[DrZOOM]

What brand is your front blue alloy bulkhead buddy?

Also ,.. is that an original Nitro Rustler front alloy shock tower or something to fit the new gearbox front end?

Nice build man! Very interesting mods. Great craftsmanship.

 

[Armysolo]

Great thread. Do the Jato big block mounts fit on the original Rustler chassis?

Not without some modifications. Keep in mind when I went with the Jato mounts I wasn't using the Rustler chassis plate anymore. I had already started using the carbon fiber plate.

YO! front breaks on a traxxas 2wd? looks way cool! how did you do the wheelie bar? I've got a Mid-motor rustler going but i can't for the life of me hack up a wheelie bar.

I'm using a Jato wheelie bar. Everything from the motor mount and back are off the Jato. Made compatibility so much easier.

What brand is your front blue alloy bulkhead buddy?

Also ,.. is that an original Nitro Rustler front alloy shock tower or something to fit the new gearbox front end?

Nice build man! Very interesting mods. Great craftsmanship.

I honestly can't remember where I got the bulk head from. Probably off Amazon. The latest pictures where the car has a front diff is off a Rustler 4x4 VXL. The differential, drive axles, A arms, Camber links, bumper and shock tower are all off a 4x4 VXL

 

[Jaydiaz1993]

I have a 2 speed nitro Rustler with a 3.3 as well except mine hits 65+mph, buy yourself a steel 50t spur gear from Here also get yourself a 24t clutch bell from Traxxas if mine goes 65 with the 3.3 if you put a big block I'm sure it will pass that forsure. Good luck

 

[Armysolo]

I have a 2 speed nitro Rustler with a 3.3 as well except mine hits 65+mph, buy yourself a steel 50t spur gear from Here also get yourself a 24t clutch bell from Traxxas if mine goes 65 with the 3.3 if you put a big block I'm sure it will pass that forsure. Good luck
View attachment 181044

Currently it has a 40T 1.0mm Robinson Racing spur and 18T hardened clutch bell. It's the smallest toothed spur I could fit without the carb hitting the transmission. I will probably go to a larger spur to help keep the front end down. When it hits 2nd gear even at half throttle it'll lift the front end up.

The big red has a lot more power yes, but what really drives top speed is the max RPMs the motor can hit. The Big Red is "rated at up to 34,000 max RPM". The TRX 3.3 can supposedly hit 50,000 RPM which I find hard to believe. A number of other people say 26k to 30k is it's true redline. I've even found old forum posts where they have a dyno graph showing the 3.3 hits 2hp at 28k RPM. I've never owned a 3.3 so I can't give my opinion but from what I've seen all the RPM ratings are grossly inflated.

 

[Jaydiaz1993]

Currently it has a 40T 1.0mm Robinson Racing spur and 18T hardened clutch bell. It's the smallest toothed spur I could fit without the carb hitting the transmission. I will probably go to a larger spur to help keep the front end down. When it hits 2nd gear even at half throttle it'll lift the front end up.

The big red has a lot more power yes, but what really drives top speed is the max RPMs the motor can hit. The Big Red is "rated at up to 34,000 max RPM". The TRX 3.3 can supposedly hit 50,000 RPM which I find hard to believe. A number of other people say 26k to 30k is it's true redline. I've even found old forum posts where they have a dyno graph showing the 3.3 hits 2hp at 28k RPM. I've never owned a 3.3 so I can't give my opinion but from what I've seen all the RPM ratings are grossly inflated.

I think getting a bigger clutchbell instead spurgear may help with top end speed and I definitely had the wheelie issue as well, for that instead of a wheelie bar I just put 2.2" tires which made it so low its hard for it to pop, although every so often it does.
The 2.2" tires also help with rolling when turning, I haven't had the car flip on me since replacing the regular tires.
I've only had the 2.5r engine and the 3.3 and all I can say it's a night and day change from the 2.5 to the 3.3 but I have no clue about the rpms or the reclining on it.

All I know is that it hits 65mph and on a good day 68mph.

 

[Armysolo]

I think getting a bigger clutchbell instead spurgear may help with top end speed and I definitely had the wheelie issue as well, for that instead of a wheelie bar I just put 2.2" tires which made it so low its hard for it to pop, although every so often it does.
The 2.2" tires also help with rolling when turning, I haven't had the car flip on me since replacing the regular tires.
I've only had the 2.5r engine and the 3.3 and all I can say it's a night and day change from the 2.5 to the 3.3 but I have no clue about the rpms or the reclining on it.

All I know is that it hits 65mph and on a good day 68mph.
View attachment 181703

I haven't been able to find a hardened clutch bell that's larger then 18T and 1.0 mod.

 

[Chubaka]

I haven't been able to find a hardened clutch bell that's larger then 18T and 1.0 mod.

Anyway you can buy one and harden it yourself?

 

[Armysolo]

Anyway you can buy one and harden it yourself?

I haven't even got the first clue on how to do that lol

 

[Jaydiaz1993]

I haven't been able to find a hardened clutch bell that's larger then 18T and 1.0 mod.

The 2 speed Jato tranny holds 0.8 spur gears, you can just get a 50t integy 0.8 steel spurgear and a Traxxas 24t clutchbell. Although I'm not sure the big block can hold that clutchbell? worth a try though if you want to reach higher speeds with it. Or if you find another way let me know, I'm genuinely curious about it