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LoweR131

Hornet bounce and ampro transmission retainer

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I've recently bought and built a re-release Hornet with my 9 year old son. Great fun buggy, but the rear end bounce makes it quite difficult to drive on ground, particularly since we've installed a sport tuned motor.

I've seen the ampro transmission retainer bracket which looks interesting, but i can't find any reviews relating to whether it help reduce the bounciness of the hornet rear end.  I appreciate it stops the clicking, but does it have a significant impact on the bounce?

Thanks in advance for any replies.

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Yes it does.

I fitted one to my first Hornet in order to stop the clicking, but test driving very quickly showed that it also improved the handling and reduced the bounciness, because it forces all movement of the rear suspension to be damped by the shocks. In stock form the rear of the motor pod is damped, but the front can move quite freely, restrained only by the two tiny springs on the pivot shaft. This un-damped movement seems to be where some of the bounce comes from, and the Ampro brace makes it go away.

It worked so well that I bought another for my second Hornet too.

While ordering Ampro bits, you might also consider the extended lower shock mounting bracket which moves the lower mounting points rearwards, Super Hornet style. This gives a rear shock angle closer to that of the DT-01 - probably Tamiya's best-handling pod-and-swing-arm buggy chassis.

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That's exactly the info i needed, thanks.

Probably going to buy the version with the battery door retainer and the battery door from them as well. Will now have a look at the lower shock mounting bracket :)

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On 6/24/2020 at 8:57 AM, LoweR131 said:

I've recently bought and built a re-release Hornet with my 9 year old son. Great fun buggy, but the rear end bounce makes it quite difficult to drive on ground, particularly since we've installed a sport tuned motor.

I've seen the ampro transmission retainer bracket which looks interesting, but i can't find any reviews relating to whether it help reduce the bounciness of the hornet rear end.  I appreciate it stops the clicking, but does it have a significant impact on the bounce?

Thanks in advance for any replies.

The problem with the stock hornet is when you accelerate the transmission pod swings up against the chassis (slapping/clicking noise) and locks until you brake or reverse. It means that the suspension is totally useless and will not work due to being locked out. The ampro retainer does work but don't expect the car to be brilliant. It's still a very crude design after all.  Hornets are great though.  The grasshopper actually has a more effecting rear suspension 

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Thanks for you comments. I certainly don't expect the suspension to be anything like as effective as my Celica Gr.B. But if the bouciness can be reduced and i can combine it with stopping the battery cover falling off, that's a win.

Looking forward to the Ampro shapeways parts arriving :)

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Are these Parts ony for Sale on Shapeways?

 

The Deliverycosts are massive for my country....

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My parts arrived this morning.

Delivery costs were around $10 to the UK. Expensive compared to the cost of the parts, but don't know anywhere else you can get them.

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I was going to order a lunchbox brace and hornet brace a few weeks ago but overall cost with postage to uk put me off. Let us know if it cures the bouncing issue.

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The shapeways parts arrived yesterday and i fitted them last night. It was a straight forward fit and the parts themselves seem to be of very good quality, albeit with a coarser finish than the factory parts. I presume this is just the finish that you just get with 3d printed parts.

I ran the car briefly last night in the dark. First impressions are that the Hornet Hop is much reduced. It's not completely gone, but its much improved and the car is a lot more stable. Its also much less inclined to flip over when turning sharply at speed. Overall, a very worthwhile modification.

Next thing to do is see if the car performs better with the rear springs spacers in or out. They're currently out, but it would be interesting to see if running the springs harder or softer makes a significant difference.

There is now no way the battery is going to fall out which would have made the modification worthwhile in its own right.

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On 7/3/2020 at 1:36 AM, LoweR131 said:

The shapeways parts arrived yesterday and i fitted them last night. It was a straight forward fit and the parts themselves seem to be of very good quality, albeit with a coarser finish than the factory parts. I presume this is just the finish that you just get with 3d printed parts.

I ran the car briefly last night in the dark. First impressions are that the Hornet Hop is much reduced. It's not completely gone, but its much improved and the car is a lot more stable. Its also much less inclined to flip over when turning sharply at speed. Overall, a very worthwhile modification.

Next thing to do is see if the car performs better with the rear springs spacers in or out. They're currently out, but it would be interesting to see if running the springs harder or softer makes a significant difference.

There is now no way the battery is going to fall out which would have made the modification worthwhile in its own right.

Did you use alternate screws to mount the brace ? Or does the hornet include screws use ? 

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The brace doesn't come with any hardware. I used Tamiya M3 *10 tapping screw when I did mine.

Have a look at Ampro's video showing the installation. 

 

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17 hours ago, Finman said:

The brace doesn't come with any hardware. I used Tamiya M3 *10 tapping screw when I did mine.

Have a look at Ampro's video showing the installation. 

 

Thanks ! That’s 10mm? Those fit good? How many did you need ? I’ll pick some up. 

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Just need two for the brace, there are a good fit - just don't over tighten them, when the screw stops resist giving it a little extra!

The end of the screw just pokes out - as in the clip.

 

 

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On 7/12/2020 at 8:01 AM, Toolmaker72 said:

Simply made my own version, can be done even simpler with a L shaped bracket filed to size 😉

46A5AFC6-AEFF-493D-9BFF-F386623A6C23.jpeg

F7EEE948-BFDA-44EE-AAAB-C9AC404D42D8.jpeg

DA5D4A23-22E5-4FFE-A0E7-0E8197C82B50.jpeg

 

 

The good think about the ampro bracket though is that you do not need to modify the gearbox in any way.  Nice bracket there though

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I thought metal to metal pivot was a better option than printed plastic to moulded plastic.  It never cost me anything and works a treat on a hopper chassis 🙂

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Does the slot you've filled in the bracket to hold the gearbox allow the gearbox to articulate as well as hinge? The slot in the ampro one is chamfered to allow the gearbox to pivot as well as hinge to enable each rear wheel to go up and down (almost) independantly.

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On 6/24/2020 at 1:40 AM, TurnipJF said:

Yes it does.

I fitted one to my first Hornet in order to stop the clicking, but test driving very quickly showed that it also improved the handling and reduced the bounciness, because it forces all movement of the rear suspension to be damped by the shocks. In stock form the rear of the motor pod is damped, but the front can move quite freely, restrained only by the two tiny springs on the pivot shaft. This un-damped movement seems to be where some of the bounce comes from, and the Ampro brace makes it go away.

It worked so well that I bought another for my second Hornet too.

While ordering Ampro bits, you might also consider the extended lower shock mounting bracket which moves the lower mounting points rearwards, Super Hornet style. This gives a rear shock angle closer to that of the DT-01 - probably Tamiya's best-handling pod-and-swing-arm buggy chassis.

How has your brace held up? Mine cracked today just over time. Wish there was a way to get it in different material

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5 hours ago, rwordenjr said:

How has your brace held up? Mine cracked today just over time. Wish there was a way to get it in different material

Mine has held up perfectly so far, however this might be because I don't jump my Hornet much. The body shell turned out rather nicely, and I don't like doing anything that might result in it not remaining shiny side up. I would imagine that if it was jumped regularly, the strain on the brace would be significantly greater and possibly lead to failure over time.

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2 hours ago, TurnipJF said:

Mine has held up perfectly so far, however this might be because I don't jump my Hornet much. The body shell turned out rather nicely, and I don't like doing anything that might result in it not remaining shiny side up. I would imagine that if it was jumped regularly, the strain on the brace would be significantly greater and possibly lead to failure over time.

I hear ya. I think mine cracked from the stress of the motor I just put in. Too much for the hornet 🥲

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I am planning to build a Pajero soon and it also has the same gear box to chassis setup.  I remember as a kid owning these cars that the oil damper hop up from the Frog was useless so I am going to run just the friction (more like frictionless) factory shocks.   

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On 7/17/2020 at 9:33 AM, LoweR131 said:

Does the slot you've filled in the bracket to hold the gearbox allow the gearbox to articulate as well as hinge? The slot in the ampro one is chamfered to allow the gearbox to pivot as well as hinge to enable each rear wheel to go up and down (almost) independantly.

It articulates perfectly.  Rather than chamfer the bracket the slot is 0.5mm larger on the diameter of the bar.  So it does tick a little when accelerating but is far stronger than a knife edge. 

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