Part 3: Building the Dampers
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| checking against old TRF416 dampers |
Some comparisons
I decided to continue the Comical Avante Build with the Dampers and compare dimensions to the old Small-Bore Dampers from my TRF416. The final, fully extended length is about 63.5mm between the centers of the eyeballs, whilst the old TRF Dampers measure around 54.6mm. Depending on how far you screw the lower eyelet on the shaft this can vary slightly. Of course you should adjust all 4 dampers to the same length.
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| about 9mm longer |
The light gray plastic dampers are pretty basic and very easy to build. One reason being the combined piston rods and plates machined from one piece. Building other “entry level” Dampers you very likely would have to cut the piston plates from a plastic parts tree. I hate doing this, since you have to cut further onto the spur and the carefully sand the remains down to achieve a perfect fit. Luckily V-Part 8, 9 and 10 are not used here.
The integrated piston plates measure 9.8mm in diameter with two sides being flattened to 9.0mm. This way no holes are needed in the piston but the damping can only be adjusted by using different oils. The kit comes with a small bottle of Tamiya yellow silicone oil which should be at 400 cst hardness, according to the manual. Playing around with combinations of different piston plates and oils would allow to further distinguish between lowspeed and highspeed damping.
Tamiya’s Small-Bore piston plates have a diameter of 9.9mm. They are lathe machined parts and don’t need to be cut out. Made from a low friction material they harmonize with the coating on the aluminum housings. Part of the reasons why TRF Dampers are premium level.
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| the old TRF piston plates are slightly larger |
The TRF piston plates would fit perfectly into the housings with very little play but I don’t have longer rods right now. The kits parts wobble a lot inside the housings in my opinion. I could imagine that this side movement of the piston rod would allow for increased deformation of the two lower O-rings, allowing oil to drain out during hard action.
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| visible gap between piston plate and housing |
Smooth Action
According to the manual Tamiya wants you to install two black O-rings. Because they are very firm I do not like to use them as they would increase the breakaway force. Instead I’m using white O-Rings from Revolution Design (RDRP2001). They are a lot softer, quite similar to clear Tamiya TRF O-Rings. Besides a bag of 16 doesn’t cost much. Hopefully the will keep the damper sealed. I applied some Team Associated Green Slime on the O-rings helps to minimize the risk of leakage.
(Tamiya Kits use different O-Rings: Black = Hard, Red = Medium, Clear = Soft and Translucent Blue = ultra Soft.)
The turquoise colored volume compensation membranes have a half spherical shape that reaches far into the housings. They are quite different to the more flat, chamfered shape of TRF membranes. Obviously they have to allow for more travel of the longer rods, but on the other hand I found them to be a little stiffer.
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| TRF membranes also fit but the collar is slightly smaller |
When screwing the caps on I used an 8.7mm long piece of fuel hose to get about 50% rebound. Mounting the diaphragm works great, I could rotate them in place and displace the excess oil without getting air in no problem. A joy compared to other dampers I build in the past where the diaphragm was slightly too large. No matter how hard I tried it couldn’t be moved all the way down without squeezing it and getting air sucked in.
The W and V Plastic Parts
The upper (W2) and lower cap (W1) screwed on to the housing (W3) a little firm when I did a first pre-fit. Make sure to rotate the caps a little backwards and push them down until you hear it click to hit the thread pitch.
Normally I like to pre-tab the thread with the Tamiya Tool #54323. This tool does not cut away material, but compresses the plastic to form the thread. It is extremely helpful especially with hard, carbon fiber reinforced plastics but quite expensive. My advice is to also add a drop of oil.
As I wanted to use the tool on the lower eyeballs (V1) I realized that they were already threaded. What a nice surprise and something I haven’t seen before. Another detail that makes it easier for first time builders. Especially when you would try to put on the eyeball without pre forming the thread, suddenly realize that it doesn’t sit straight or requires too much force and might risk scratching the piston rod.
According to the manual plastic spacers (V3) are used on the rear dampers to limit the suspension travel. I’m not sure if this is done to increase the tendency to wheelie or prevent the chassis touching the ground. However I left them off for now and will check the lower arm movement on the car.
I prefer the car to wheelie less but stay planted for a fast and controlled ride.
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| there isn't much oil left |
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| waiting for the air bubbles to come out time for some taco salad, ok just leftovers from yesterday |
Conclusion
The Comical Avante comes with plastic dampers that can be regarded as cheap and entry level. This doesn’t meant that they don’t do the job and need to be replaced with fancy blue aluminum units right away. I think the opposite is the case, they perform smoother than I had expected. Moreover several features make the build an ease for beginners, reduce the number of parts and also likeliness to make mistakes. Softer O-rings can reduce initial friction but have to prove that they seal correctly. Maybe longer piston rods with some left over TRF pistons would reduce play and allow for more setup options. Around 32mm too 37mm in length should fit.
For sure the Blue TRF Option Dampers (#54670) look amazing. The price for these is even lower than on other TRF damper sets, as they look great but don’t seem to have the low friction coating on housings and shafts, which would be a waste should sand find a way inside.
Regarding the Comical Avante as an entry-level, fun-car I doubt I will ever use it in a competitive way where superior performance is needed. Therefore I decided not to throw heaps of money at it. However I will check if my old TRF416 dampers fit the car with longer lower eyeballs (V2).
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| they work better than expected |
Highgrip - Always getting high on 𝝁