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Kol__

Kol's Madcap Astute Mongrel

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16 hours ago, bavee said:

Where on earth did you find that TTC gearbox?

Nice one!

 

13 hours ago, Goudar said:

What a great gearbox you go there, pretty jucy.

 

Thanks guys, I picked up the original, vintage TTC in a rather expensive:blink: purchase of a Madcap it was fitted to. I have now disassembled that car, started to use the TTC on this car and the chassis is destined for my future build of a mint shelfer Madcap, as its the cleanest chassis I've been able to acquire to date.

Since considering the option of fitting a 2018 Super Astute TTC and then looking at acquiring the parts to build one, it is apparent that it is now near on impossible due to the discontinued parts by Tamiya and the rarity of what's out there now globally amongst both shops and private sellers. So it happened that a nearly complete, unused one popped up on eBay this week (anyone on this forum perhaps?), I struck a deal for it and some other rare Astute parts and now am fitting that to the car instead.

The modern slipper clutch on the TTC is much better in my opinion, sure it doesn't have the nostalgia, but I have that in the original TTC that will now probably go in a shelfer or become a stand-alone piece on the shelf. What it does have is a better design and construction, with much more adjustability.

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Fitted the aluminium gear support brace that came with the vintage TTC (these are about £40 delivered to the UK from the US if purchased separately) and this should ensure even more reliable running.

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The 2018 TTC purchase didn't come with a polycarbonate gearbox cover, so I picked on up from Revive RC. Very good quality, not quite as detailed as the original vintage cover, but very good and very tough as well.

I pushed the gearbox plate into the cover...

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...and cut it out with a sharp blade...

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Using the vintage cover as a guide I then marked and cut out the hole for the slipper clutch adjustment nut with a scalpel. I considered drilling this, but it proved a little tricky to find the dead centre of the circular top section where the hole sits. Cutting it out was a bit of a ball ache as the polycarbonate is really quite thick on this repro piece - I consider that a good thing though of course as it should prove very durable I hope.

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Beyond the photo above (which shows the rough cut done with the blade) I sanded the hole to shape, periodically testing the fit of the little plastic dust cap that fits in there for running. I was able to shape and centre the hole in the case and then ended up running a 10mm drill through it. Result was a nice snug fit, but it took a bit of time and careful consideration.

Existing Madcap/Astute ball diff gearbox with standard 70T spur before removal. Note the carbon gearbox plate, which is a nice touch on this one.

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Cocked up on the pinion for the 2018 TTC though! The vintage TTC is able to take between an 18T- 23T pinion.

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As I was originally planning to fit the vintage TTC until I found its shortcomings, I had bought a 19T pinion for the gearbox switch. It wasn't until I fitted the 2018 TTC and offered up with motor and 19T pinion that I realised it wasn't going to work with the 2018 standard 82T spur gear. The 2018 manual states it will take a between a 23T-27T pinion gear, so 19T is well beyond that spectrum.

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With the motor rotated right forward it hits the casing...

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...and the 19T pinion can't mesh with the spur gear...

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Paying a but closer attention or doing a little more research on my part could have flagged this up sooner, but hey ho. There is a lack of steel 0.5 module pinions out there. Although below the 23T limit stated in the manual, I have managed to pick up a 22T one and considering the 19T is almost able meet with the spur gear, going up 3 teeth I hope will enlarge the diameter of the pinion enough to mesh well with the standard spur gear.

@Fruitfly01, do you know where I can source other 3 spur gears for the 2018 TTC that you mentioned in a previous post buddy?

So for now, here she is fitted, with no pinion for the moment of course...

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Beyond the pinion hold up, some other minor issues:

*The adjuster lock nut fitted to the end of the slipper clutch shaft was incorrect and when set up at the standard setting (tighten fully and wind back 2 and 3/4 turns) the nyloc part of the nut was pretty much all off the shaft, which would be no good for running. Luckily I had some of the correct nuts, so fitted with no bother.

*As my 2018 TTC purchase didn't come with the polycarbonate cover, it also didn't come with the dust cap for the slipper adjustment hole (part A5). So I have currently fitted the vintage cap. Not ideal as it leaves me without one for the vintage one of course. The part is from the Super Astute A parts tree, which in the past few months seems to have become uber rare (along with most other Super Astute parts), so it's unlikely I'll be able to pick one up. As I know the hole is 10mm, I think I'll look for a 10mm rubber bung for this runner.

*The seal around the clear gearbox casing is pretty poor and I can see dust and dirt will easily get in. I don't think that is an issue with the aftermarket cover, as I've read before that this can be a shortfall with the TTC gearbox. So I am looking at some 0.5mm or maybe 1mm very thin gasket material that I could cut to shape and fit around the edge of the gearbox plate to gain a better deal from the elements. Not sure if that will works, but it's worth a shot I reckon.

Anyway, so currently I await the arrival of what I hope is a suitable pinion to be able to progress to running the buggy again...

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1 hour ago, Kol__ said:

 

So I am looking at some 0.5mm or maybe 1mm very thin gasket material that I could cut to shape and fit around the edge of the gearbox plate to gain a better deal from the elements. Not sure if that will works, but it's worth a shot I reckon.

That looks like it really means business with all the machined aluminum etc. 

Would a tiny bead of transparent silicone or similar (or just grease?) achieve a dust seal where you'll have a close fit in places and a gap in others? A gasket might stretch the polycarbonate and risk cracking it if it isn't sized to take one. 

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You've done very well in finding that (2018) TTC.....  I've just started looking for any Astute gearbox and diff for an upcoming project and they are really scarce now !

 

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What a true piece of art. This TTC looks awesome.

 

It's really hard to find a solution, without spending a lot of money. Is there any improvements that can be done without a bucket of cash or launching a treasure hunt ? Seems there is no "easy" way.

I found this metal bracket but I don't know if we get a real improvement.

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Thanks guys:) Yeah parts for the Super Astute have become super rare now and pretty pricey. I was informed last year that more parts were due to be available from Tamiya in the first quarter of '22. However, I've now been told that Tamiya have discontinued production of all parts for the Super Astute. I just picked up a second set of slipper clutch friction discs (and pressure plates) this week, so that I have a spare set if/when the discs are used up on this runner. I have no idea how long they'll last?

I'll have to tot up how much I've actually sunk into this car now, but I can say with certainty it's a fair chunk by now. For me this is the first proper buggy I bought (within a week of getting back into the hobby in Sept '21) and although largely Super Astute now, is still somewhat reminiscent of the Madcap which was my favourite buggy back in the 90's, not that I owned one back then though:( So it's heart over head on this build. Plus I'm hoping it will make a really good runner, but time will tell on that one.

Yeah the grease could work @BuggyDad, cheers mate. I saw someone had suggested something similar for the Mad Bull gearbox on here as well. I think they said it says in the Fighter Buggy manual to apply grease to one area to prevent the ingress of dirt into the gearbox. Don't know if I can bring myself to take that approach on this particular gearbox, as the clear cover will show all the mess. I'm already thinking that the first time I run it, I'm going to have to take off the cover and give it a good wiping out!:blink::ph34r:

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8 minutes ago, Kol__ said:

Thanks guys:) Yeah parts for the Super Astute have become super rare now and pretty pricey. I was informed last year that more parts were due to be available from Tamiya in the first quarter of '22. However, I've now been told that Tamiya have discontinued production of all parts for the Super Astute. I just picked up a second set of slipper clutch friction discs (and pressure plates) this week, so that I have a spare set if/when the discs are used up on this runner. I have no idea how long they'll last?

I'll have to tot up how much I've actually sunk into this car now, but I can say with certainty it's a fair chunk by now. For me this is the first proper buggy I bought (within a week if getting back into the hobby in Sept '21) and although largely Super Astute now, is still somewhat reminiscent of the Madcap which was my favourite buggy back in the 90's, not that I owned one back then though:( So its heart over head on this build. Plus I'm hoping it will make a really good runner, but time will tell on that one.

Yeah the grease could work @BuggyDad, cheers mate. I saw someone had suggested something similar for the Mad Bull gearbox on here as well. I think they said it says in the Fighter Buggy manual to apply grease to one area to prevent the ingress of dirt into the gearbox. Don't know if I can bring myself to take that approach on this particular gearbox, as the clear cover will show all the mess. I'm already thinking that the first time I run it, I'm going to have to take off the cover and give it a wipe out.

Kind of why I thought of silicone Sealant. If you could get a really really thin bead on there then it might be near enough invisible. And I think it would dismantle pretty easily, it's not much of an adhesive.

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The 0.5 module spur gears are found on the DF03 chassis.  There is or was a DF03 spur gear set available which contained a 78T and 85T spur gears.  There was also an 82T spur available that came with the DF03 slipper clutch , and is also fitted to the Super Astute 2018, so that's probably what you already have.

The original TTC has an 89 tooth spur, so would take smaller pinions.  At the time, 18T to 23T pinions were all that was available, until the DF03 came out and larger pinions became available.  I think I have a 26T pinion fitted to my original TTC on my Madcap.

It didn't even occur to me that there would be meshing problems when using smaller pinions on the new gearbox.  Now I'm not even sure if a larger spur gear will fit under the TTC Lexan cover, but if it does, you might be able to lower the tooth count on the pinion and still have a good mesh.

The old TTC is geared much higher than the new one and it was recommended that low turn brushed motors were used.  A Dynatech O2H with a 10x2 rotor is suggested when using a 20T pinion.

The new TTC is pictured with a brushless motor in the Super Astute instructions, although no information on it's winding is given.  The gear ratios given would make the new TTC more suitable for use with higher wound brushed motors such as silver cans, and still be able to maintain a respectable speed.  

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Thanks @Fruitfly01, I went ahead and picked up the set of DF03 spur gears, so now have the 85T cog and looks like it will fit under the lexan gearbox cover without any issue.

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So my options are to run the Reedy Fury 12T motor with either of the below, the first of which is the stock setup -

*82T spur with 25T pinion = FDR 3.28

*85T spur with 22T pinion = FDR 3.86

Doest seem like much of a difference there really. I can simply try both of course, but anyone know what will perform better?

Also, bonus! ...the Super Astute kit has two of the plastic slipper clutch adjustment caps across 2 of the parts trees, so I've ended up with a spare for this build!:)

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I love your Madcap/Astute, looks great and the holiday buggy rims are a great idea.

Regarding the FDR , with a 12 t motor you would be looking at approx 7.00 FDR I would have thought.

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15 hours ago, Snappy1 said:

I love your Madcap/Astute, looks great and the holiday buggy rims are a great idea.

Regarding the FDR , with a 12 t motor you would be looking at approx 7.00 FDR I would have thought.

Thanks @Snappy1

I've not got much knowledge on the FDR stuff tbh. Can't remember where I got the calcs from for the above, but how are you getting to 7.00 FDR bud? Cheers

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7 FDR is a good place to start when working out what suits your cars setup, I have only done a minor amount of racing , and it was vintage classes, I setup for around 7, the people at the pointy end were around the high 5’s to low 6’s FDR, that was racing silver cans,  

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1 hour ago, Kol__ said:

Thanks @Snappy1

I've not got much knowledge on the FDR stuff tbh. Can't remember where I got the calcs from for the above, but how are you getting to 7.00 FDR bud? Cheers

You haven't quite got your FDR calculations right. You need to multiply those values you have by the internal ratio of the transmission (2.59 - it is in the back of the manual) so your 82/25 is actually 8.5 FDR, and your other option is 10FDR. For a 12 t brushed off road I would try 10 FDR and see how it goes. I was running a 12x2 brushed at 8.6 FDR in my TA02 on road last summer and it was really flippin fast! With bigger buggy wheels and more drag on the surface, go for the 10 FDR and see how fast it is and how hot the motor gets. Also worth noting I had to make a custom motor plate for my Thunder Dragon to get a 10ish FDR to run a 17t brushed without it getting too hot, but your super astute is much lighter and more efficient so will be easier on the motor. 

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Thanks @ThunderDragonCy, that really helps me out a lot buddy:) FDR makes a bit more sense now and I had no idea they listed the gearbox ratio in the manual.

So when I run those figures through an FDR calculator, as you say I get the below -

*82T spur x 25T pinion x 2.59 ratio = 8.5 FDR

*85T spur x 22T pinion x 2.59 ratio = 10.01 FDR

So does the 10.01 mean it will have more acceleration and less top speed than the 8.5 setup? So if that's correct, it will be kinder to the motor? Cheers

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@Kol__ No problem. Happy to help. You are correct. Slightly confusingly the higher the FDR number the LOWER the gear, so a 10 FDR will be slower top end but accelerate faster. 

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On 12/21/2021 at 8:05 PM, Kol__ said:

 

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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.

@Kol__, I saw this the other day and don't recall having the issue on my big buckled Madcap.
The simple answer is that the shock tower base is shallower on the Astute. I've a suspicion that an original Madcap shock tower base might be a drop-in replacement. It naively looks like the main difference is just the depth where the turnbuckle is attached. Your geometry would appear to be something close to Madcap spec.

Yes - I see my tower has a split in it at the turnbuckle. My box of bits indicates I have a spare original I can swap in to replace. No idea what I used to break from that tree, as I have 2 spares, one of which is mint. Probably the rear suspension lower wishbone inner brackets, so I might go find some spares.

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Cheers @naturbo2000, I've since changed out the rear camber turnbuckles for the standard Super Astute ones, as the plastic ends are not as long or as bulky, so gives a little more room for the spring. I was looking at the issue again yesterday and I've decided to cut some of the plastic off the rear camber turnbuckle mounting point on the rear hubs. Got some spares anyway and the C trees are still produced for the Blitzer Beetle etc. so are plentiful. I've fitted a different set of shocks as well, so I need to get an update on here:)

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This is a bit tricky to explain but with Madcap rear suspension arms coupled with ball end / ball adjuster type upper links the result can be driveshaft ejection.  With Madcap rear arms and upper links with ball ends, the rotation of the adjuster on the ball allows the rear arms to flex under torque load and it can be enough to spit out a driveshaft.  Pinch the top and bottom of a rear hub between thumb and forefinger and rotate the hub ( in the opposite direction to driveshaft rotation ).  This assimilates the torque reaction through the rear hub under acceleration and you will see what I'm trying to describe.  If your worried about the amount of flex or if the car spits out a driveshaft the answer is actually to go back to standard so the upper link hinges on a pin and therefore it hinges on one axis only.  I use a modified Astute set up coupled with the flexible Madcap or Astute rear arms.... its the original hinge pin and the original inboard Astute B5 part with 4mm threaded shaft.  This prevents the hub from twisting backwards as it better secures the entire rear suspension allowing it to only hinge on one axis which is the normal suspension travel up and down.   

Turnbuckles / upper links with ball end and ball adjuster are only a Hop-Up when using Super Astute rear suspension arms and this is because the SA rear arms do not flex under torque load.  I hope this is helpful but again.... only  a problem if you eject a driveshaft.

 

 

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Thanks @Thommo. I presume it's best to use a hinge pin at both ends of the upper arm. No maintenance issue whilst using Madcap lower arms as I still use the threaded rods to attach either end of the lower arms to the chassis, which are more easily removed than the Astute e-clip rods.

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Yeah, I do use a hinge pin (shaft) at the outer end also.  The front upper part of the Madcap hub is trimmed off.  The hinge pin goes through the hub after running a 3mm drill through it.  The upper link has a ball adjuster on it but with a DB01 suspension ball inside it and then an O'ring behind the E-clip to eliminate play and put some pressure on the link.  The DB01 suspension ball and O'ring is the trick here.... it keeps things tight and with hinges at both ends, the hub cannot twist under load.

Before I learned this, the Madcap rear suspension arms twisted so much (on landings mostly) I had lower arms pull completely out of the short Astute BB4 screw pins in the rear hub and driveshaft ejection or both !  One time the driveshaft just spat out while cornering.  Each time was on grippy astro.

   

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Strongly reccomend using a 37mm shaft with E'clips to connect the rear hub to the suspension arm as per Super Astute.

What ever power you're putting into it is loading into those hubs and arms and then into the arm mounts to the chassis..

 

 

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Thanks @Thommo, interesting stuff. Not quite sure I follow you on the upper link hinges and hinge pins stuff. Are you talking about the fixed length plastic camber arms from the Madcap? Got any pics bud?

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Sure thing !   Going back to your OG plastic Madcap upper arms and screw pins would be an improvement.  Upper links with ball adjusters just allows the hub to twist horribly when under power using Madcap or Astute rear arms .  Give the hub a twist in the opposite to rotation of the driveshaft to check.  The twisting is the suspension arm flexing but only because the swivel action of the ball adjusters on the upper link are allowing it to move. 

Below set up the hub and arm cannot twist because the 3mm shafts with E'clips (hinge pins) prevent that movement.  

 

 

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