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Kol__

Kol's Madcap Astute Mongrel

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On 10/7/2021 at 3:58 PM, Collin said:

Hi there. This is really a great guggy you got and I am glad you did not over-restored it. I love it so much that you still can smell the racing history of this buggy. Shiny shelfies are nice but you can never immitate a vintage runner/racers spirit.

Thanks @Collin, appreciate that mate, but I'll confess that although I do have some reservations about stripping this buggy of it's historical mods and character, I do have further plans (see below). Tbh I just want something I can completely make my own, improve in my own way and... build 2.0

Minor update...

I sourced some nylon spacers from eBay to replace the rubber/silicone tube spacers the original owner had fitted to the 'unknown' front arms. Tiny ******s as you can see (AAA battery in shot for scale)

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I bought some parts from a US ebay seller. So I now have the Super Astute battery holder pieces to mount the battery lengthways front to back on the chassis and put some weight further forward - anyone know if I will need a shorter bodied steering servo to fit these parts? The manual shows a real stubby looking one fitted to the chassis. Also, I now have the OG hex head posts (can be seen in the little bag on the bottom left of the pic below) that go into the top of the gear box where it mounts to the chassis - that'll be the last of my custom hex rod mounts, they didn't stay on the chassis for long, lol. And I acquired the rear bumper for the Super Astute - that should fit better under the motor, as the Madcap one I've fitted is in constant contact with the motor, the SA one appears to have a shallower curve, so should resolve that issue. Got the SA shock towers for less than $5 so chucked those in so I can compare specs and heights etc. with the unknown carbon fibre shock towers currently fitted to the buggy.

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Added a new set of Grasshopper 2 tyres to the front, not my fav tyre but in light of limited options and the rarity of the OG fronts, these will do fine.

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Installed a new low profile servo to make room for the new Super Astute battery front mount and will use the old one in my ORV chassis.

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Also fitted a servo saver and turnbuckle steering rod from a donor car.

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So I've converted the car to the Super Astute front to back battery layout and fitted a Hobbywing 1060 ESC, with the intention of running the Reedy Fury motor that came with the car when I got it (not refitted it yet).

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I've also noticed that upon closer inspection the carbon fibre front and rear shock towers are clearly custom made. Not perfect, but they do the job and it's nice to think someone knocked them up 30 odd years ago:)

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Vintage Reedy Fury motor refitted...

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Also serviced the rear shocks with a clean and new oil (35W) and added a steel pinion 23T, lifted from a donor car

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Also had a spare body shell from the donor car, came sprayed up metallic grey and is not perfect by any means, plus a few cracks and poorly drilled body mount holes, but it will work nicely for this runner. Bought some aftermarket stickers, which are not great tbh, but again as it's a runner not bothered about that.

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Haven't had a chance to run the car with these changes yet and still a few more plans in the works, but it's nearly there now as a regular dry day runner.

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Took the buggy out for its first run today, since the recent mods.

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It drove really well, it was light, quick and well balanced. However, with regular checks to the temps on the motor and ESC (by finger touch) they were both way too hot to keep a finger on after 5mins or so run time. The car then seemed to drop off in performance, which I thought maybe was battery, but having turned the car off and on again it was back to full speed and then quickly dropped off again.

To clarify, the current set up is as below -

*Vintage Reedy Fury motor - think it's 12T

*23t steel pinion

*70T standard spur gear 

*HobbyWing 1060

I'm assuming that the HobbyWing 1060 ESC cannot handle this motor and is going into limp mode as overheating. And is the 23 tooth pinion too much for the motor? I could fit fans I guess, or just upgrade the ESC? Thoughts guys? Cheers

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On 11/21/2021 at 10:35 PM, Kol__ said:

Took the buggy out for its first run today, since the recIt drove really well, it was light, quick and well balanced. However, with regular checks to the temps on the motor and ESC (by finger touch) they were both way too hot to keep a finger on after 5mins or so run time. The car then seemed to drop off in performance, which I thought maybe was battery, but having turned the car off and on again it was back to full speed and then quickly dropped off again.

To clarify, the current set up is as below -

*Vintage Reedy Fury motor - think it's 12T

*23t steel pinion

*70T standard spur gear 

*HobbyWing 1060

I'm assuming that the HobbyWing 1060 ESC cannot handle this motor and is going into limp mode as overheating. And is the 23 tooth pinion too much for the motor? I could fit fans I guess, or just upgrade the ESC? Thoughts guys? Cheers

The 1060 can take a 12 turn motor, according to it's specs on paper, however you are very over geared for such a powerful motor.  The 23t pinion/70t spur as standard on the Madcap is for standard silver can motors the car originally came with.  Tamiya's instruction recommend the use of the 77t spur and a 13t or 14t pinion for their  Dynatech 02H motor which is a 13 turn motor, revving around 25,000 rpm.

I would be inclined to follow Tamiya's recommendation and use their suggested gear ratios.  You can always gear up if the motor and ESC remain cool enough.

Back in the day, it was often recommended to run milder motors in the Astute and Madcap buggies in order to preserve the drivetrain - specifically the ball differential, which doesn't always hold up to mega powered motors.  17 and 19 turn motors seemed to be the recommendations.  A Dynatech 01R at about 22,000 rpm was ideal.  A modern Stock RZ/TZ/BZ rev just as high, and have more torque on paper.

The ball diff works well, but does require some maintenance and many spares and rebuilds after so many runs.  When you notice the diff starting to slip, it's time to rebuild it. The wilder the motor, the quicker the diff will fail and require a service.   I've seen a diff melted through, although that was from a King Cab - same gearbox.  If you look after it and don't ask it to handle too much power, the diff will work ok, in my experience.  Upgrade the internal components to the metal parts used in the Egress, and sold separately as a hop option 53043.

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I utterly destroyed a Madcap transmission with a 14t double back in the day. 12 turn is probably a bit beyond what it could have handled :)

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Thanks for the motor/transmission advice @Fruitfly01 and @Howards, appreciate the input, I've just been distracted but other projects and other mods on this build.

Update on recent mods:

I replaced the central steerage linkage bar with a turnbuckle in an attempt to take some of the slop out of the steering.

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However, that didn't do much to improve things. So then I replaced the whole steering set up with Super Astute parts. Just had to add a few washers to the bottom of the mounting posts to ensure the steering linkages didn't collide with the Madcap front bulkhead, as that is a different shape to the Super Astute.

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And Tamiya turnbuckles fitted all round.

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The rear shock is just flicked up out the way in the above pick. As with the original Madcap upper non adjustable camber arms, I still have issues with the shock spring rubbing, in this case now on the turnbuckle. You can see I've added a couple of nuts and gone with longer mounting screws to move the ball end back a bit to stop this.

I've also replaced the homemade carbon fibre shock towers and rear mount plate with carbon fibre Super Astute versions.

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This has given me a different ride height. The chassis seems to be sitting quite high now. I do have a set of Tamiya hi-caps that I was saving for another build, but I think I'll try those on here for now.

I also have a TTC Super Astute gearbox that I'm going to fit. Just waiting for a 19T 0.5 module pinion to arrive. What you guys think of that gearing setup with the 12T Reedy brushed motor?:wacko:

So with all of the above, the build is certainly more Super Astute than anything else now really, but it should perform better I hope.

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Update:

So I kept the grey metallic shell for this runner, but I've removed the white mono tone graphics and gone with a yellow and dark grey colours scheme.

These are MCI stickers, customised to my spec...

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I've added the rear wing mount from a Top Force.

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Full on with the level of stickers here, but for me its a racing runner so I want this one stickered up. In addition to MCI I've used a few from an old truck set.

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The wheels are from the Holiday Buggy. At 2.2" (60mm) diameter all round, it gives me some more options for front tyres and I've gone with a set of Schumacher 'mini spike slim' 2WD tyres in a hard compound. I feel these are as close as I'm going to get to the uber rare front tyres (of which I do have a new set, but would never run them and they are destined for my box art Madcap shelfer - a future project).

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The rear tyres are the Madcap stock Tamiya 53059's.

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Might not be to everyone's tastes and I'll admit I'm getting a bit obsessed with matching yellow with other colours in two tone colour schemes on my RC cars! I'm happy with the results though and I was pretty lucky that the yellow of the MCI stickers is a good match with the Holiday Buggy wheels.

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Next, I'll be fitting an original TTC Super Astute gear box which should resolve any of the potential issues with running the Madcap ball diff, but will be yet another step away from the Madcap. Going to run it with a 19T pinion. Anyone know if that will be a good gear ratio with the 12T Reedy Fury motor setup? Cheers

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Nice job there, freaking awesome color livery mix perfectly with the yellow stickers. Impressive.

I'm looking for Schumacher tires for my next rebuild. I struggling to get appropiate wheels with right tires.

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@Kol__ somehow I missed this thread until now. So great to read through from start to finish. Clearly a real passion project and a sympathetic resto done so well. And then all topped off with a great colour and decal scheme.

This is another instance (there are more and more thanks to this forum) where a car I thought I had no interest in is suddenly shown in a different light. Love it such great work!

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That is a cracking looking Madcap.  Love the colour scheme.  I have several Madcaps, although I only run one that is quite heavily modified.  I've kept mine all plastic, so I can't take advantage of too many Astute parts.  The steering on mine still has some play due to the Madcap bellcranks.  Are the Astute bellcranks tight and slop free?  I have a Dynastorm, and the front wheels will not budge a millimetre, left or right, unless the servo says so.

According to the TTC manual. the gearbox can handle the hairy motors of the day, so should be Ok with the motors you choose.

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I'm running mine with a Stock RZ on a 25 or 26 tooth pinion with no problems.  Surprisingly, these larger pinions fit the TTC as the motor mount allows the motor to be moved out further.  These larger pinions were not officially available for the TTC back in it's day, 23 teeth being the largest, and the 0.5 module was new and unique to this gearbox, and possibly just the Super Astute.  The Dynastorm got released with 0.4 module gears, which were also new at the time, but were shared with many of the Touring cars as upgrade items.

The new TTC gearbox also uses 0.5 module gears, but has a formulaic design, shared with many other cars, including the DF03 chassis buggies.  Three spur gears are available, giving you a range of gearing options, but it's not as unique, original, or nostalgic as a 90's TTC transmission

Excuse the showing off, but I wanted to display my NIB, which I'm proud to own.

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Thanks @Goudar and @GeeWings, the buggy has evolved in my ownership and changed a lot. I'm happy with the result and looking forward to running it once the gear box is fitted and the capacitors added to the Hobbywing 1060 ESC. I'm a little bit conflicted that it doesn't really resemble much of what I bought it like, so much has been replaced now. However, I've really enjoyed modding it and now the car is with me, its my vision and in this guise it lives another day and will always be a (mostly vintage parts) runner!!

Thanks for the info @Fruitfly01 There is still a small amount of play in the Super Astute steering set up, but no way as much as the Madcap linkages.

That original TTC gear box set is awesome! I thought the rere TTC gear box was exactly the same as the original one, what's changed between the two?

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Re the TTC on the 2018 Super Astute, it had a major redesign compared to the original and includes a beefed up machined motor plate, and redesigned slipper assembly. Manual comparisons attached. 

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19 hours ago, DGunn1 said:

Re the TTC on the 2018 Super Astute, it had a major redesign compared to the original and includes a beefed up machined motor plate, and redesigned slipper assembly.

Thanks @DGunn1, yeah quite some significant differences there!

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The new slipper clutch was a big bone of contention among purists when the Super Astute was rereleased.  Despite it's limitations, the old TTC was quite functional and capable, and a perfect example of Tamiya doing things their way with their quirky and experimental over engineering.  What we really wanted was a TTC with an up to date and strong ball differential.  Instead we got a modern slipper clutch with the same old planetary geared diff and a super thick aluminium gearbox plate.   

The new slipper clutch is a normal slipper clutch with a formulaic design, found on every other car that has a slipper.  Look at any of Tamiya's cars with slipper clutches, and look at any other manufacturer's slipper clutch designs.  There's not much difference between any of them.  Some time ago, a slipper clutch design that worked was designed, and has been used ever since.  Gone are the days of the TTC, MDC, and Losi's unique Hydradrive.

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Interesting, thanks @Fruitfly01. I have the old TTC gear box, as pictured above, and plan to fit that to the Madcap here. Hopefully it will run well and will last for occasional running, not as if there are any spares available. Or would I be better off sourcing the new version of the gearbox I wonder? - a pricey option though!

 

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11 minutes ago, Kol__ said:

Interesting, thanks @Fruitfly01. I have the old TTC gear box, as pictured above, and plan to fit that to the Madcap here. Hopefully it will run well and will last for occasional running, not as if there are any spares available. Or would I be better off sourcing the new version of the gearbox I wonder? - a pricey option though!

 

The Super Astute rerelease actually came with a set of the original TTC gears in the kit, although they are not used, of course.  As a result, original TTC gears can often be found for sale.  Running an original TTC needn't be a risky venture, as long as spares are still available.

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On 1/7/2022 at 10:16 PM, Fruitfly01 said:

The Super Astute rerelease actually came with a set of the original TTC gears in the kit, although they are not used, of course.  As a result, original TTC gears can often be found for sale.  Running an original TTC needn't be a risky venture, as long as spares are still available.

Yeah I think the gear parts trees/packs are mostly the same between the original and rere, it looks to only be the spur gear that changed and the original one is included in the rere bag and just not used. Also, I think the internal fitment of the small gear that slots onto the end of the slipper clutch main shaft once it's been pushed through the gearbox case has changed from bi-hex to just hex, guessing they might be interchangeable.

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So onto the start of the gear box mod. This should be the last key part in getting this buggy up and running as a regular runner.

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Included was a metal version of the gear support, a decent upgrade! UR1XMOv.jpeg

Odd looking grease in here...

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Also, a crack the forward screw hole for the planetary gear cover, not really a biggie though.

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And some minor damage here, which I think I can just clean up with a knife...

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Mostly broken down...

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Diff opened up, all looks ok and a good amount of grease in there...

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19T 0.5 module pinion gear

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Now to rebuild her. Thinking AW grease in the planetary gears as the rere instructions state. Maybe ceramic grease for the rest off the gears?

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Got around to putting the gearbox back together. AW grease in the diff...

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Rebuilt the slipper clutch

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The clutch friction disc was worn and actually damaged from use. The centre has been cut out by the hexagonal section of the shaft. New on right Vs used on left...

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You can see that once built up as per the manual, a portion of the hex sticks out past the inner plate. Not sure why this is, as it clearly enables damage to be inflicted on the disc.

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I tried using spacers to resolve this issue, but it pushed the spur gear out a touch and when fitted was rubbing on the polycarbonate gearbox cover. So I've just put it back together as the manual.

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Went with Cera Grease HG for the gears

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