Tamiya TRF417x Rally - WIP

[MiniT-Mdz]

Hi guys!!

I've been lurking on the rally subforum for a while looking at all the cars. I remembered I had my Tamiya TRF 417x sitting around doing nothing in the junk room for 2 years. I’ve been thinking about its future, I could sell it and then buy a XV-01, or I could convert it into a rally car. I’ve just decided it’s time to dust it off and give it a new life as a rally car.
The main problem is to make a cover to protect against pebbles and gravel. I’ll try to make it by cutting 0.8mm polypropylene sheets.
I’m going to use some stuff I found into a drawer of my last season in TC Stock Series two years ago, so it will have:
Chassis: Tamiya TRF 417x
Motor: Hobbywing 10.5T sensored
ESC: Hobbywing Justock 45A
Servo: Futaba 9451
Radio: Spektrum DX3R

Anyway, here's some pics where I'm on this car…

Comparative between rally suspension geometry(on the left) and TC (on the right), ground clearance is 20mm on the front and 22mm on the rear, droop is about 5mm.


Starting the lower cover…





You must perforce cut off the downstop spaces of the CF chassis to reach plenty of ground clearance for rally tracks



Diff cover:

[MiniT-Mdz]

I’ve put a 4mm spacer under the front suspension mount in order to get 5º of anti-dive(kickup) for better handling in rough terrain and besides it increases the caster angle. In adittion, I’ve changed the diff position from upper to lower position by moving the eccentric mount. Other adjustments such a roll center, wheelbase, camber, toe… will be set when I run the car on the track.



Having a chassis that has more flex, can, in theory, run better on rough tracks. That’s why I’ve increased chassis flex by changing the upper tray setup. I’ve removed the 4 center screws and now, the subchassis is just screwed from one end to the other.

[MiniT-Mdz]

To be continued...

[natskiboy]

Wow I raced those chassis and its painful to see it all scratched up. Lets see how good your covers are

[MiniT-Mdz]

Last week I ordered a set of Fastrax block tires with HPI wheels from UK, have just received them today. It seems Fastrax tires are much softer than Tamiya blocks. I think they're good value for money.

[MiniT-Mdz]

Here's some more pics of the trf417x rally...

[going2fast]

super cool

[MiniT-Mdz]

Another little update... Just pick up a couple of kawada 48pitch spur gears. Trf417 comes with 64pitch gears which are smoother and more efficient than 48p, but 48p are more durable and stronger, perfect for dirt using. Kawada spur gears perfectly fit into trf417.

[MiniT-Mdz]

Skid plate made of 0.6mm metal sheet. It's necessary to protect the CF chassis nose against scratches




Yesterday I finally received my Subaru Impreza body, just painted it

[MiniT-Mdz]

I tried out a set of vaterra kemora tires, good looking tires but they're very soft compound and definitely are not for loose soft tracks. I think they work better on hard-packed tracks.

[stroker613]

Looks great!! Should be a sweet rally rig!

[MiniT-Mdz]

Originally Posted by stroker613

Looks great!! Should be a sweet rally rig!

Thanks man!

[MiniT-Mdz]

Another update... I've used balloons as dust covers on steering linkage. It's an easy way to keep pebbles and dust away, what do you think guys? Is anyone using something like this?

[lonleycreeper]

Very cool idea, I think I may steal that idea myself.

[MiniT-Mdz]

Originally Posted by lonleycreeper

Very cool idea, I think I may steal that idea myself.

Yeah, i hope it'll work well. I also tried out with road bike inner tube, but it's too rigid so the suspension doesn't work properly.

[MiniT-Mdz]

Here are some action pics from Test Day #1.

[MiniT-Mdz]

I've not finished it yet so the setup wasn't the ideal one, but i couldn't wait for another day without using it

[Smile]

I really like this project, very unique in its own way.

[lonleycreeper]

Looks great out in the dirt.

[going2fast]

picked up some great ideas from this post .. thanks man and keep it up