Tamiya TRF419 Wide Front end Mod

Since playing around with the lower profile shock towers I have also been experimenting with other handling modifications and parts. One o...

Since playing around with the lower profile shock towers I have also been experimenting with other handling modifications and parts.

One of the things that I and others who have been racing the low profile towers have all noticed is the increased cornering speed. This actually has make things quite interesting when looking at the classic front end geometry that we have been using for year.

The convention that most of us TRF racers has gotten used to is C front/front and and C rear/rear this width has always been a good starting point and most of the time front end grip has never been an issue with our TRF cars. (rear end a different matter).

With the lower towers and the increased corner speed the front has been really positive, not actually hard to drive, but more positive. Yet and whilst the car is overall much quicker I was keen to investigate to see how it could be improved, one thing that I had noticed even before playing with the low towers is that the 419 seemed to be pretty easy to drove with a wider front end.

Messing around with a few numbers at lunchtime with one of my work colleagues (Who specialises in handling dynamics and physics) we looked at the the geometry of the front the car and surmised that looking at the extra corner speed, spring compression and geometry of the lower arms that a wider front end would give the car a more linear movement.

The widest blocks that Tamiya make are the F-Blocks so I went and delved into my pit box. The first problem was that Tamiya doesn't make any split blocks wider than the C-Blocks so I just took out two F-blocks with the idea of flipping the Front rear block over.

Here was the second problem, the front pulley rubs against the block, so it was time to get filing and make sure that there was sufficient clearance.
Neat filing here by a friend who also has also done this mod (Mine was a little more ahem basic)
With this done I had my new wide front end. So time to take the car down the track :)

Track test

The car felt good from the off. I was partly expecting the new change to actually reduce grip even thought I was assured that it would be better. The car was not leaps better, it just felt easier to drive consistently and the mid corner speed seemed better with the front wheels being less willing to slide if the speed was too high.

I was really enjoying the racing and I was flying around the track. The track was large, but the carpet was not very grippy as it was very cold. However nothing could touch the car and I qualified top to head the A-Final

The A-Final started well, I raced away at the start, and despite a couple of pressured laps at the start I soon worked out a considerable lead of nearly a lap. I was weaving past the back markers and I could really tell that the corner speed was much higher than some of the other cars as I could even go around the outside on a wider line on some of the tighter sections and ride past the back-markers thanks the quick corner speed.

Unfortunately I got a little carried away, I was speeding around some of the lapped cars and I was getting a little cocky, then it happened As I approached the fastest corner on the track I dived into the corner braking late and weaved to the inside of the the car but I whacked the corner board at almost full tilt (13.5 boosted).

There was a clap, the car landed back on it's wheels and I drove away.. but something felt very odd.. it soon became much more strange as the arm sinked into the car and It came to a stop by the podium.
As I had feared the modified block had bent. I had filed a lot away and it was quite narrow. Despite withstanding some hard hits over the previous 3 races, the epic crash proved just a little too much. (It also smashed an upright.. first one I have broken on the 418 style of suspension).

The bent block allowed the shims to fall off followed by the suspension shaft to fall out making the arm collapse. Despite the accident I was pleased with the result. The car was feeling fantastic before that. The only problem is how can I run the F-Block again without this happening.

The Road Ahead

Now I had done some track test with the prototype I set about designing a new temporary part in Cad that I can have machined up.
The part will be ready to test soon 
This is the new wide front end block. I will be much stronger than the modified block. It will not be as smart or sexy as a new TRF F-Block, but I have designed it to be easy to machine. In the meantime I will just be running another modified F-Block and waiting to get one of these back to test :)
TRF419 5368795092309646958

Post a Comment

  1. If you are using the standard arms I think you'll find the front track is wider than the 190mm allowed in the rules

    1. It is getting tight, but I had no problems ensuring that the car was in the 190mm width. (I didn't run the 0.5 mm spacers on the front wheel though). I think you could even go to a G block if they existed.



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