Avante hop up questions

[BuggyDad]

I've got an Avante 2011 to build. I might not start it soon but it's got me thinking a little. Essentially, I want to build a nice one. I originally thought box stock but then I looked at the Black Special and it got me thinking a bit. The racing steering set seems like a straight up improvement without being a modern mod, so it's in the Avante spirit. The stock Avante gear diffs aren't sealed, so the torque splitter set with the ball diffs in seems like an option, and it's model/period correct. Most likely though I'd keep the central ball diff and run it pretty tight. Athough I'm interested to try the one way it doesn't seem to me like the right way to go.

On the steering, the racing set is probably impossible to find but I can CNC the bridge and buy the cranks and posts and from there it's achievable with standard hardware I reckon. 

On the diffs, I'm chatting with @svenb about an original set 53034, but can anyone tell me whether this is identical to the rere set 47389 and if not, how not? And also whether you think running old ball diff plastics in a rere is unwise?

I'm kind of thinking that those plastics should not be a common failure area and the metal parts should last forever, so it seems a reasonable addition. I won't put serious power through it, probably about Superstock level max. Which reminds me, the kit motor, is that about that power level? 

[toyolien]

I have a new racing steering set I could be persuaded to part with, if you fancy it.

[BuggyDad]

5 minutes ago, toyolien said:

I have a new racing steering set I could be persuaded to part with, if you fancy it.

Ooh. Will PM you. 

[toyolien]

Ok. Just gonna check in my spares.

[Saito2]

The central ball diff is not adjustable and should be run tight. It pairs well with front and rear ball diffs, taking some of the "edginess" away from the buggy. Though the center one-way torque splitter is there as a tuning option, few seem to prefer it.

The original ball diffs are quite different than the re-release version. The re-re diffs are more modern in their approach and adjustment. The original diffs were shim-style, relying on installing varying numbers of shims placed within the diff to alter tension. There were comparatively laborious to adjust but didn't loosen and maintained adjustment better, though the range of adjustment was more limited vs the infinite adjustment afforded by a traditional diff screw. These were the style of diff that frequently failed in the King Cabs, etc. The Egress however was blessed with stronger alloy diff housings (vs the pot metal versions in the King Cab, Astute, etc.) which didn't bend and distort. These are the same diffs found in the old 53034 kit.

If Jamie Booth-style suspension modifications that alter front kick-up are in the cards, the original style diffs must be used. The re-re ball diffs rely heavily on the the Avante's unique front suspension geometry that placed the front diff outputs in line with the suspension pivot points.

As far as the gears themselves, despite new plastic always being preferable, they were constructed of fiber reinforced PA plastics less supportable to age than usual Tamiya ABS/PC.

The original Avante came with a Technigold for power level reference, though the drivetrain overall is pretty durable.

 

[BuggyDad]

3 minutes ago, Saito2 said:

The central ball diff is not adjustable and should be run tight. It pairs well with front and rear ball diffs, taking some of the "edginess" away from the buggy. Though the center one-way torque splitter is there as a tuning option, few seem to prefer it.

The original ball diffs are quite different than the re-release version. The re-re diffs are more modern in their approach and adjustment. The original diffs were shim-style, relying on installing varying numbers of shims placed within the diff to alter tension. There were comparatively laborious to adjust but didn't loosen and maintained adjustment better, though the range of adjustment was more limited vs the infinite adjustment afforded by a traditional diff screw. These were the style of diff that frequently failed in the King Cabs, etc. The Egress however was blessed with stronger alloy diff housings (vs the pot metal versions in the King Cab, Astute, etc.) which didn't bend and distort. These are the same diffs found in the old 53034 kit.

If Jamie Booth-style suspension modifications that alter front kick-up are in the cards, the original style diffs must be used. The re-re ball diffs rely heavily on the the Avante's unique front suspension geometry that placed the front diff outputs in line with the suspension pivot points.

As far as the gears themselves, despite new plastic always being preferable, they were constructed of fiber reinforced PA plastics less supportable to age than usual Tamiya ABS/PC.

The original Avante came with a Technigold for power level reference, though the drivetrain overall is pretty durable.

Hey that's interesting stuff. It kind of feels like if the original ball diffs are adequately durable and good for maintaining their setting, but less adjustable than the rere ones, then they may be good for me. Once set, I expect to leave it be I would think. Does the Avante have as much strength in its diff housings as the Egress, such that it can handle these old ball diffs as well as the Egress? It sounds like that's what the diffs rely on. 

[Saito2]

By diff housings, do you mean gearboxes? They are the same between the two cars. All the diffs, Avante planetary gear and new/old Egress ball-style, are relatively durable and unitized or self-contained.

BTW, you can take a look in the old Egress manual here on Tamiyaclub to see how the old-style diffs go together.

[BuggyDad]

23 hours ago, Saito2 said:

By diff housings, do you mean gearboxes? They are the same between the two cars. All the diffs, Avante planetary gear and new/old Egress ball-style, are relatively durable and unitized or self-contained.

BTW, you can take a look in the old Egress manual here on Tamiyaclub to see how the old-style diffs go together.

Ah re diff housings I was just noting your point above that the diffs failed in some cars but were solid in the Egress because of its alloy diff housings. I thought from that you were referring to gearboxes? 

[Saito2]

22 hours ago, BuggyDad said:

I thought from that you were referring to gearboxes? 

No, sorry for the confusion.

By diff housings, I meant the four shiny metal pieces in the top left of this photo of the original Egress (and Avante hop-up) ball diff set.

[BuggyDad]

23 minutes ago, Saito2 said:

No, sorry for the confusion.

By diff housings, I meant the four shiny metal pieces in the top left of this photo of the original Egress (and Avante hop-up) ball diff set.

Gotcha. Fair point. My experience with ball diffs is limited.  think I've only seen them with metal parts here and I can well see how plastic here might deflect/fail under the pressure. 

[Saito2]

4 minutes ago, BuggyDad said:

I can well see how plastic here might deflect/fail under the pressure. 

Sorry again if I was unclear. Those same type of parts in the King Cab, Astute, Madcap, etc. were made from inferior die cast pot metal that could distort when the diff was drawn up. The original Egress ones pictured were made from a stronger alloy.