Tamiya TBEvo6 Exo-6 Vs TBEvo4 MS Track Report

One of the RCRacer team was ready for the first track outing of a Tamiya Evo6 with the Exotek EXO-SIX conversion fitted. So we thought it would be good fun to have a head to head battle with a TB-Evo4 (MS) that was gathering dust in my loft for many years.

A little bit about the Evo's

The Evo6 has been a great car, but the Exotek conversion promises to push the handling even further from the std Evo6.  The driver used the Evo for a while and then moved onto the TRF419 and the Evo was retired until the Exotek conversion came out.

The Evo 6 all ready to race.

the Evo6 was all prepared, with a Revention Pro, Trinity D4-13.5t motor installed. Which was already going to give the car a speed advantage over the 17.5 blinky Hobbywing motor installed in the Evo4.

The Evo4ms was a slightly different story. Thanks to a busy days work, I only managed to retrieve the car from the loft briefly before I got to the track. The car hadn't been used for some time and it was previously set-up for running foams. So I just made a few bench fixes to quickly put it in the right ball park before setting off  on a race. The Evo4ms was actually my favourite Evo, I always preferred the handling on this to the Evo5.

At the track

So first up, we noticed that we had a different motor configuration. This was going to be a slight issue, but we thought that we could at least employ a basic handicap system to re-calculate the overall times.

Handicap
The formula we will use to compensate for the 17.5 car would be to give it 3% more speed by taking 3% off the avg lap and then dividing that into the race time (300 seconds) to get the handicapped result. This might not seem a lot, but as you can see with the race video, the track is very tight and technical.

The cars at least had the same batteries!

The first issue for the Evo4 happened whilst on the bench. I revved the car and I noticed something fly out and the car all of a sudden started to be RWD! I was puzzled at first but then noticed that the rubber O-Ring that holds the shaft pin had just snapped as it had fatigued over all the years of non-use. I managed to find the pin, but without a spare it looked liked it was all over before it began. Obviously everyone was trying to find a bodge to fix it, after a few ideas were dismissed such as taping it in, or using a cable tie a genius solution was to use a Tamiya Axle pin on the shaft. It was a pain to fix on the propeller joint, but after one failed attempt saw it spring away into the air, one was finally fixed on. The result was great, and it was almost as if it should be a stock part. It will be staying on there for now.

Race 1 (The beginning)

The cars ready to face each other on the track

Evo6: The car was really fast and I could notice that fact that it was very quick off the line compared to the TRF419 that I normally race. The car however did not feel as comfortable to drive, partly as I had to get used to racing a shaft car again, but crucially as the car didn't seem to have the cornering that I normally get from the 419. After a few minutes into the race the tyres started to come good and the car felt easier to drive. Not as easy as the unmodified Evo6 or the 419 but it was starting to come good.

Evo4: The car was slapped down on the track with the shaft pin fix taking away any preparation time so I wasn't expecting much. The car was slippery away at the start and I was down on speed. The speed passion only has 10 degrees of timing and whilst it was cranked all the way up the gearing felt a little out (Proved by the motor not even being hot at the end of the race). The other main issue was that the car had the turning circle of a bus. The car itself though was really easy to drive so I coasted around, working out what changes I needed to once I got back to the bench after marshalling.

Results
Evo 6 Laps 48 Time 303.229 Avg Lap 6.31
Evo 4 Laps 46 Time 300.714 Avg Lap 6.53
HCap Laps 48 Time 304.037 Avg Lap 6.33
Winner = Evo6

Race 2 (The rematch)

Evo6: I made a few changes to the car. Mainly front camber, and gearing.

The gearing needed to change

The car was wheel-spinning so I wanted to gear it lower to give me more top end, and to take out the edginess of the car as it was under acceleration. The start went well, and the car felt much more planted even by the first corner. The front camber change also made the car feel a little more stable on corner exit. However all was not great, the gearing had taken a bit of the kick out the car, but the motor was heating up a lot. The lower gear ratio was not really giving me any more speed at the end of the small straight, and it also killed a bit of the corner exit speed on the infield.

The Evo4 needs a little bit more preparation for the next rematch

Evo4: I fitted a larger pinion for more speed and also checked the steering throw. A slight problem is that the servo horn I added to the car was not tall enough to give me full lock, as otherwise it would be hitting the centre prop shaft. Also the car did not have DCJ's so when the steering was not even at its extreme limit there was a lot of shudder along the drive train.. I forgot how bad it used to be before we had DCJ's. On to the race and the car was better, having some steering was a big boost. The car was still down on speed and all of the other cars were over me, however the car was incredibly easy to drive and I managed to keep the 13.5 X-Rays behind me thanks to a wide car and some very good driving etiquette from all involved.

Results
Evo 6 Laps 49 Time 304.557 Avg Lap 6.21
Evo 4 Laps 47 Time 300.070 Avg Lap 6.46
HCap Laps 48 Time 300.778 Avg Lap 6.23
Winner = Evo6

Race 3 (The final)

Evo 6: I had changed the gear ratio back to something very similar to the first race. I played with my transmitter and added a little expo to calm the acceleration and keep the torque steer at bay. The race started and the car felt good. I kept the lead and I maintained it comfortably. I was at one point on for the FTD but that did fall away as the race continued. I was however running much better, but a collision with the barrier sent me on a spin and that ruined my laptime.

It's a showdown.. can the Evo4 do it in the last race...

Evo 4: I went to an even larger pinion, and I also started to play with the wheelbase to give me more rotation as I didn't have a longer servo saver. This helped a little and the car was much better around the corners, but still not sharp enough for the track. The gearing worked however and I was running faster in this race than previously. I was still never going to match the 13.5 cars for speed but I was able to hold the X-Rays behind with some very steady driving. This was proven with my average lap being only a tenth of a second out from my best lap.

Here is the race video

Results
Evo 6 Laps 49 Time 303.551 Avg Lap 6.19
Evo 4 Laps 48 Time 305.633 Avg Lap 6.29
HCap Laps 50 Time 305.065 Avg Lap 6.10
Winner = Evo4
(Ok so that is a bit of a turn up for the books.. however we cannot really tell until they both have the same motor as our 3% might not be accurate).

Overall 

Evo6:  The Evo with the Exotek conversion felt great, and even after a few races the Exo-Six conversion feels like a step up from the stock layout. After only 3 races the car was feeling much better, but there is a lot of room for improvement to match the speed of my current TRF419. I can tell that there is a lot more speed to come from the car, but I will need more track time, so I intend to run it a few more times to see how it progresses.

The Evo 6 was just a narrow victor.. there is more speed to be unlocked in both cars

Evo4: Despite no tuning, old tyres and a motor set-up that was low on umpfff. The Evo4 was a pleasant surprise. I always thought it was the best of the early Evos (Including the 5). The car is in desperate need of a proper service and some TLC if I want to race it properly.  I have to admit I would be tempted to get the Evo4 conversion designed by Eric Bresser (See here). However even the original car could easily be upgraded with TRF418 suspension parts and DCJ's at the front.

It was a fun club night, and it shows that even with our old cars we can have fun at the track. The question is do we take the trouble to keep them up to date, or just buy the latest car?

For more reading check out the build of the EXO-SIX conversion And check here to see Eric Bresser's excellent EVO4 conversion (Part 1 and Part 2)