It's all be done before. Or has it? Top Force LWB, ARB's and durability mods

[slydar 242]

This will be a slow burner, but I now have a friend in the club I race at who owns a CNC router . For the idea's I have this is a big plus. 

I have been on and off working on my DF01 trying to prepare it for racing. My goal originally was to build something that was somewhat capable of club racing against modern buggies, as from "reading the internet" this seemed to be an achievable goal. 

I no longer fully agree with what is sometimes implied, but I'm invested now. Both monetarily and emotionally.

I ran the car at the track quite a lot by myself just practicing. While it wasn't super reliable, it seemed enough so that with a few of the common available mods, it would be. The car now has those mods and in my experience, they haven't been a satisfactory solution. The track where I run is a big part of the issue with breakages. It's a "synthetic" surface, which in basic terms is a course sand, packed down with PVA style glue solution in it. It's also very high grip, which probably isn't helping, but overall it's a great track and a a great club, so we will persevere. 

The Top Force is also extremely light compared to my modern race buggies. Which makes it harder to drive, which, you guessed it, cause a greater number of crashes, I don't want to completely change the design/spirit of the car though, but I will be adding some things to help it work with the lower weight, so, here are the plans.

LWB chassis. Compared to a modern buggy, the Top Force is quite a short wheelbase, coupled with the light weight, it can get unsettled much more easily. The car currently has the YR modified alu prop shaft. this gives normal dog bone style ends. this opens up the possibility of using other shafts of similar design,  standard YR shaft is 168mm. I am aiming for something 12-15mm longer. Another reason for me to do a custom chassis is to go back to 2.5mm FRP. I think this will help durability, with the flex taking some energy away from the gear cases. Especially the front gearbox/chassis lower junction. if possible, which it looks to be, I will extend front section of the chassis here to pick up the rear 2 lower gearbox holes. 

The rear gearcase/arm amounts is another issue. while there are some neat solutions already offered, I want to stay a little closer to stock, something someone might have done at the time of the cars release. so I will just be adding longer hinge pins, and cross braces front and rear. the rear also tied into the rear gear cover probably.

Rear ARB will be mounted to a plate at the front of the tower, which I will integrate the mount for a brace from the tower to the gearbox. Traditionally done with a turnbuckle, but I will use another FRP plate, so that it works a little better in tensions and compression. 

Front ARB will be mount on another FRP plate, mounted on top of the front gearbox by drilling through the bumper holes. may or may not help durability, but it's the neatest place for it I think. 

Will do some towers in FRP too. For a little more flex again to absorb some of the energy before it gets to the gear cases. maybe some design changes to the rear, for stock length and maybe integrate the race mount into the actual tower.

Lastly, Customised front gearbox cover. I will "fill in" in between the back of the tower and cover, probably use epoxy filler for this at first. I can then add through holes drilled through the tower/bulked J part, screwing into the added material. could potentially print this part, but is a pretty complex design with the bearing locations. 

Very long post with not much action  "Top" points if you read the whole thing. 

This is what the car looks like now   It will look quite different though when done 
 

 

 

[matisse 1626]

Sounds super interesting!  There is a custom LWB car out there somewhere, seen a few pics on here and on FB, but for the life of me I can’t remember who built it.

im sure someone will though. 

[GeeWings 2859]

The world of racing is something I've never played in (and realistically never will) but it's really interesting so I'm intrigued by the process you are going through and the decisions you make. I will be following this closely.

BTW, great looking Top Force, I hope some of the aesthetic remains!

[slydar 242]

5 hours ago, matisse said:

Sounds super interesting!  There is a custom LWB car out there somewhere, seen a few pics on here and on FB, but for the life of me I can’t remember who built it.

im sure someone will though. 

There's quite a few. Some UK ones which seem to emulate to a degree some works cars campaigned in the 90's. Some euro ones which are a little wilder with quite significant changes to the rear gearbox/suspension area, one of which was posted here semi recently. 

I guess I am going for a little closer to the first example, but even more "period" aesthetically. 

 

[Howards 641]

Is there a slipper clutch mod for these? Wondered how people could race them without them to be honest. Seemed like a wild omission from the original design. 

[matisse 1626]

6 hours ago, Howards said:

Is there a slipper clutch mod for these? Wondered how people could race them without them to be honest. Seemed like a wild omission from the original design. 

I’ve never seen one.  We all got very excited when Full Option made a prototype slipper for the egress, looked like it might presage one for the TF

[ThunderDragonCy 8379]

7 hours ago, Howards said:

Is there a slipper clutch mod for these? Wondered how people could race them without them to be honest. Seemed like a wild omission from the original design. 

A guy did a build a couple of years back on here using a Carisma slipper pinion 

[slydar 242]

15 hours ago, Howards said:

Is there a slipper clutch mod for these? Wondered how people could race them without them to be honest. Seemed like a wild omission from the original design. 

It isn't something that bothers me. I race 2wd and 4wd stock, in my 2wd car I use a slipper eliminator. In 4wd stock the motor  size is 13.5, which on high grip is about the realistic limit of the transmission, so for me it works out. 4wd stock is still extremely fast, and a good somewhat realistic goal for a car  which was a little behind the times as far as race kits are concerned, 30 years ago when it was released

Certainly a slipper, or center diff of some description can be an advantage/reduce lap times, but that is also straying a little too far from the original design. 

IIRC, the Manta Ray came first, novice/intermediate/price point level car, never intended to race competitively. Even the TF at the time of its release, with loose surfaces, low grip tyres, and low torque brushed motors I don't see need for one. 4wd cars don't really need a traction aids, and now you have so many settings in your TX and esc they're definitely not 100% necessary.

[ThunderDragonCy 8379]

@slydar Don't know if you are on Facebook but Jamie Booth and Lee Broadhurst are sharing pics and setups in their recent championship winning TRF Manta Ray LWB.

https://m.facebook.com/groups/1621288184785986/permalink/3094214557493334/

If not, seems they use the hop up Tamiya manta ray prop shaft and the extra length comes from using the long front Egress prop outdrives at both ends. They seem to be using some kind of Parma body that Penguin are doing repros of 

[pUs 314]

It certainly has been done before, both back in the days and in more recent vintage racing. I can only agree about the weight, with LCG lipos my ’std’ Top Force is just too light. Been playing around with lead weights, most on right side, to achieve a more even weight distribution.

There was a proper anti squat mod done back then so I consider it OK from a vintage point of view. Borivojes kit (Custom RC Parts on ebay) is just super - very precise and solid, and actually makes it a bit easier to work on the rear end as well. Has a modern touch on it with different flippable inserts for various anti squat / toe variations. On top of that, his rear gearbox cover also strengthens the rear damper mount a lot. The whole thing can be run completely neutral as well, i.e std kit geometry.

I don’t think a slipper is really needed but I actually prefer ball diffs on it,  that gives at least a little chance of slip in extreme situations. Only problem is to manage the spline setup, it’s quite easy to rip them up. The outdrives needs to be secured. Some use c/a glue, others shoe-goo or similar stuff.

 

[slydar 242]

On 3/5/2022 at 10:05 PM, ThunderDragonCy said:

@slydar Don't know if you are on Facebook but Jamie Booth and Lee Broadhurst are sharing pics and setups in their recent championship winning TRF Manta Ray LWB.

https://m.facebook.com/groups/1621288184785986/permalink/3094214557493334/

If not, seems they use the hop up Tamiya manta ray prop shaft and the extra length comes from using the long front Egress prop outdrives at both ends. They seem to be using some kind of Parma body that Penguin are doing repros of 

Yeah Lee builds the cars and Jamie just drives them it seems like. They both attended "Oldschool RC Euro Masters" last week and I'm pretty sure they 1-2'd. Lots of other Top Forces too. I like his solution for a longer prop shaft but my car was built from parts, so to achieve what he's done I'd need to source a standard shaft AND the egress parts. I've found a few options already for longer shafts to suit my ends, in stock at a few local shops
 

[slydar 242]

14 hours ago, pUs said:

It certainly has been done before, both back in the days and in more recent vintage racing. I can only agree about the weight, with LCG lipos my ’std’ Top Force is just too light. Been playing around with lead weights, most on right side, to achieve a more even weight distribution.

There was a proper anti squat mod done back then so I consider it OK from a vintage point of view. Borivojes kit (Custom RC Parts on ebay) is just super - very precise and solid, and actually makes it a bit easier to work on the rear end as well. Has a modern touch on it with different flippable inserts for various anti squat / toe variations. On top of that, his rear gearbox cover also strengthens the rear damper mount a lot. The whole thing can be run completely neutral as well, i.e std kit geometry.

I don’t think a slipper is really needed but I actually prefer ball diffs on it,  that gives at least a little chance of slip in extreme situations. Only problem is to manage the spline setup, it’s quite easy to rip them up. The outdrives needs to be secured. Some use c/a glue, others shoe-goo or similar stuff.

 

I like bora's parts, and he's a great resource. But I just want to see how it handles with the longer wheel base and swaybars before altering the rear geo. I already have some extra toe from the knuckles, some small amount of anti squat would probably be good but I don't run a very aggressive anti squat setting in my race cars. One reservation I have about bora's rear end kit is the TF has a lot of rear overhang already, and our track surface is very abrasive, we run skid plates to stop the rear end wearing away. Seems like the added D block would cop a real hiding on  TF the way it is.