wtcc5's TT-02 race development and race reports: Version 5.2 release

[wtcc5 5902]

*** Unfortunately my previous image host shut down, so a lot of pictures are gone. Please go to page 10 here to see version five (and newer) including race reports with pictures of this development series. ***

 

Two and a half years ago I started to develop the TT-02 for serious racing. The path until now was full with good decisions and dead ends. As I have the hope to race and practice soon again (which means I will continue the improve the car), I want to share the all the steps I took and race reports with you.

It will start with posts that show how it all began. I hope you will enjoy it.

[wtcc5 5902]

How should I start...
Right in time for the 2018/2019 indoor season, my joy for RC is returning strong. The fever got real strong when AE announced the TC7.2. I also checked what kind of racing series will be held here in south Germany. And so one evening I discovered the RCK-Kleinserie. RC-Kleinkram is one of the biggest RC shops in Germany and this year it starts a new series with four classes. One of these are GT with the proven TT-02 as required chassis. The GT-Sport is the open TT-02 class for all TT-02 variants, including all tuning parts (even non-Tamiya).

The rules for GT-Sport are made for me  No minimum weight, 17.5t motor (Ruddog), 5.0 gearing, blinky esc, free rubber tire choice, body must be GT (like PF Ford GT or Tamiya GT bodies) with at least real looking color scheme.

At least two races will be held in my region, not far away...
That was the point when my brain started planning the total-TT-02-RC-war-wtcc-style 

So I looked in my hobby room what I have left over from my RC career and found a lot spares from my AE TCs, my Xray T4 and spares from the FF03. I took over one half the kitchen island table (my wife wasn't happy) and started checking what is possible. And if you like the TT-02 chassis or not, it is capable to become everything you want with compareable little effort. The more I work and drive with this car, the more I love it.

And this is how the story starts.

[wtcc5 5902]

Here is the link to the racing series:
RCK-KleinSerie ? You race, we care!

This was my starting point:



A base TT-02 with ball bearings, aluminium shaft and oil filled shocks. Of course I leave off not needed parts like the rear bumper or the fan-motor-cover. This 2 year old chassis already won a race in the Tamiya Euro Cup and was a DTM-, WRC- and a Super GT-car before.

[wtcc5 5902]

My next step was to think how to implement a full adjustable suspension. Additionally I wanted to get rid of all the plastic covers. I know they are perfect to keep dust and dirt away from all the gears, but I find them quite ugly. All these parts flew off the car.

Of course this caused more problems at first. The covers also hold the driveshaft and all bearings in place. I remembered a old conversion I did with the TC6 to make it fit Pro10 bodies. I replaced the upper bearing cap with a shimmed cfk plate. This time the small plate should be multifunctional with including the camber link and the shocktower mount. So I would need 4 small plates for the shocktower, camber link and to hold the diffbearings in place and two more plates for the driveshaft bearings.







Here you see the car with TC6.2 shocktower. They were hold by old AE servomounts, which I shortened for the "lightest TC car" project, once. The hole distance was so small, that it was really tight to fit without rubbing the differential. In between I installed the TRF416 suspension from my FF03. It nearly fits, just the arm pins needed to be shortenend by 1mm. This made me very happy.

Up to now I wanted to use mostly parts from my old cars to keep the costs low. Because tuning a TT-02 seems so ridiculous...  I am still not sure if I am a little crazy/stupid doing this. I had to think about how judgemental I thought about people who bought tuning parts for several hundred dollar for this chassis instead of buying a pro rc car...

Well up to now everything went together quite nice. My conversion reached the level of a TT-02S and I haven't spent a dollar, yet. Still missing though were antirollbars and a way to adjust droop. The both problems were solved with more small cfk-plates.



The design and production takes its time. Until this stage I had thought, drawed and dremeled for 4 days. And everything worked  Then my attitude changed: Why going through all this "hassle" and then only having the second best components with this handmade look... Thank you very much, brain! 

[wtcc5 5902]

In between some "normal" tuning parts arrived:



The Yeah Racing motor mount and the Tamiya high speed gear set are very useful for the right gearing. Also the Ruddog 17.5t motor arrived. The combination of these components with a 80 theeth 64dp spur gear and a 41 theeth pinion works like charm. I accidently discovered that the motor cooling cut out at the front end perfectly avoids the tub plastic for the rear drive shaft bearing. This way it would be possible to use a 40 theeth, maybe even a 39 theeth pinion on a 80 theeth spur. Awesome!

With the motor so far inside I will try to use a 6000mAh shorty lipo and should reach the optimal r/l balance.

[wtcc5 5902]

Above I mentioned, that I wasn't fully satisfied with the look and the precision of my conversion so far.
So I sat down and did some more measuring and build parts in CAD. There I optimized some distances and went for a practical look. The principle with the cfk plates stayed the same. The changes mostly occured with the shocktower mounts (now with hole for the camber links) and the anti-roll-bar-mounts. These now look like the normal mounts, but also replace the outer cfk plate shims:



Blue are all plastic parts, cfk and arb-wires are grey


Of course I don't produce the plastic parts myself. After very good experiences with the KR-MF bulkheads, it was clear that I can trust sintered Nylon parts. I prepared the data for Shapeways:



And ordered the parts:






At the same time I ordered the cfk-plates as well. I hope they will arrive on saturday.


If you want to take a closer look at the parts --> I opened a Shapeways shop for fun:

https://www.shapeways.com/shops/kr-modellautosport-teile

[wtcc5 5902]

Last update for today:

Part of trying to get the best performance out of the car was not only to use some parts that "could do it", but use the best. Well, and I ordered a new high performance touring car chassis with the TC7.2, so my Xray T4 is actually a roller. As result of this thinking, the TRF416 suspension went back onto my FF03. I also bought a new TT-02 tub chassis for 5,49€ (my old one was tweaked). It got the full T4 suspension with arb, hard plastic hubs and graphite arms. At this point I must admit to be very happy that Tamiya and Xray agreed on the same sizes for hinge pins and axles. It was pure plug and play. After a little pondering I decided to buy the TT-02 Type-S steel suspension mount set (54634). This should be more durable in a chrash and allows to drive (inboard) toe at the rear. Unfortunately Tamiya got the measurement a little wrong: The whole pin setup has more slop than I hoped it would have...



What is left of the TT-02 from the beginning? The tub chassis, the drive shaft, differentials bearings and servo mounts 
Maybe some of you recognized these strange "screws" standing out of the tub chassis near the differentials. I want to try something else here. We call it "Stehbolzen" in Germany. The online translation says stud, stay bolt or stud bolt. The idea is to conserve the thread in the tub chassis by using a M3x16mm set screw and a nut screw to tighten (like you would with an aluminium engine block).

[DeadMeat666 1677]

Excellent thread, following for sure!

I believe some of the CF parts that you need are already being sold by fibrelyte. Don't forget to check them out before going through the trouble of designing/cutting your own, unless you'd rather do that  

[wtcc5 5902]

@DeadMeat666: Thanks! I forgot to delete one sentence above. Sorry about that. The project is more developed than this. I will continue with udates tomorrow. You are right! I should have known fibrelyte before, that would have been good for my work.

[wtcc5 5902]

Parts arrived 
Today the carbon plates came. I am very impressed by the quality of the milling and the carbon.


(8. September 2018)
 

[wtcc5 5902]

(10. september 2018)

[wtcc5 5902]

So far the car has had no esc, no droop screws. It still needs a proper battery position for balance, an initial setup, a bumper, body stays, even a body...
Today I added the esc, did all the soldering, found a rough position for the battery, added the droop screws, setup droop and anti-roll-bars.








I am very happy that the car with battery and electronics is in a window for the perfect r/l balance without additional weights. I prepared my scales and setup wheels. In the coming days I will search for the front/rear position of the battery to get proper tire loads.

(11. September 2018)
 

[wtcc5 5902]

The rears are angled more than I like. The problem comes from the arm geometry, which is symmetrical at Tamiya. With the TT02S steel armount set designed that way I would need to heavily treat the arms or the mounts, not knowing if this will work out properly.
I need to check if I find a solution to this problem...

Oh man... sometimes, you just need to get a kick in the *** to find a solution / remove the brick from your head.
I just looked at the badly angled rear axle again and suddenly thought: „Hey, are you stupid?! You got everything to resolve this matter in a minute!“ I just needed to replace the front pinball of Tamiyas steel armmount set and the hinge pin with AE parts, add 9mm shims and that’s it. Before I thought I had to drill a larger hole into the arm or cut down the steel ball cup...





The front will be lined up perfectly, too. Just not today 

(11. September 2018)
 

[wtcc5 5902]

Today I lined up the front. This time it was just putting shims behind the arms and turning the steel front mount 180 degrees. It got some threads at both ends that I don‘t know what they are for? With the arms so far in front they are in the way (of course).

And a picture from above. All arms lined up the car looks more compact than before. The wheelbase is now the same/like my TC7.2.


 

(12. September 2018)

[wtcc5 5902]

Time for some basic setup before setting it on the scales:



1.5* camber front and rear
Front toe out 1*
Rear toe 3*
Front 4* caster
Droop: 6mm in front and 5mm at the rear
Weight without body, tires, bumper and body posts: 1026g

 

Accomplished two more tasks.
First I added the bumper base and the body posts:





And then I put the car on the scales to look how bend the chassis and prototype parts are and where to put the battery:





The result shows once more how good the quality of the Tamiya TT-02 is. The chassis was on the scales with spacer that replace the springs (they go on the shock shafts). This should reveal every unbalanced weight placement and badly produced parts. Already the electronic side is well balanced. With the shorty I then could make it near perfect. Again a good day with the car.

Next tasks will be shopping for an Urethane bumper and an awesome GT-body. I decided for the Ford GT until yesterday when Bittydesign announced their new GT body. Now I need to wait.

(15 September 2018)

[wtcc5 5902]

Some more pictures of setting the car up:




 

[wtcc5 5902]

After I found out some minor mistakes in the produced parts due to wrong measurements, I updated my data:





As you can see I optimized the shocktowers and shocktower mounts. Both are placed 1mm towards the center of the car, the lower screwhole vanished and the ball cups get more space. I added a score in the lower middle of the shocktowers to allow for easy l/r balance check. Before I had a 1mm hole, but that is stupid difficult to use, not sure what I thought... The rear shocktower also had a change with the holes for the body posts rising 2mm. Otherwise the upper shock eyelit will not fit in the most outside hole. The ARB-clamps got a change on the nipple to pay respect to the manufacturing tolerances. Near unvisible changes also happened to the front drivetrain ball bearing clamp and all plates to accomodate the new shocktowermount design.

The downside of these changes... I will not profit as my setup works like it is (with a very little one time help of my Dremel) and I don't think someone else will ever jump this "bus"...

 

Parts arrived in the mail today 

One thing that was on my mind for several weeks now, is the maintenance jam (is that right, from Google translate?) with my Xray SLP shocks. The plastic parts do their job since october 2014. The rubber membrane and o-ring are at least 1 year old. So it was time to renew them:









Now the SLP shocks are smoooooooth as silk. Still the best shocks I have ever owned.


Then the new urethane bumper came and the diffinsert to make it a spool:





The bumper needed a little trimming to avoid the ARB-clamps. Later in the week I will mill a carbon brace to hold it firmly in place.


The installation of the spool insert showed how good you can work with the car after the conversion. In the end I had to do not more or less than on a normal competition chassis to get the front diff out.







The products of Yeah Racing always include some good ideas and are therefore quite attractive. Unfortunately the precision is a bit off. I already had problems with the fitting of the motor mount. Now the insert needed force (not brute force) to get in the diffcase. Then the outdrives needed brute force to be fitted. Everything will work fine once in the car, but this imprecise production makes you think...Next time original Tamiya parts?

(18. september 2018)

[wtcc5 5902]

Today I made the upper bumper brace from one of the last cfk parts I have laying around. A very subtle design, but I like it:




For the last days I continued with preparing the Corvette body. When I placed it on the chassis for the first time, I recognized how wide wheel arches stand out. Did I buy a 200mm body? No, it is 190mm, then the TT02 is just 180mm wide... I totally forgot! Puuh, it looks uncool already. I can't stand that:








That is not the way I want to drive around the track. What now? Somehow there must be a way to make the track wider. At first I thought of doing something with the arms, but I don't want to weaken them with an extension or even cut them and then see that my idea doesn't work. The real challenge are the inner mounts. My approach was to use the original inner mount hole to hold a fitting insert that takes the pin 5mm to the outside. To prevent it from spinning in the hole, it is designed to cling to the inner chassis walls. The outer mounts just got a little more material and revised holes that will stop the pin from going through and adapt to the toe angles:



At first I wanted Shapeways to print it in aluminium, but that would be far too expensive, so I will try their professional plastic...

(20. september 2018)

[wtcc5 5902]

I had a hard time deciding if I should go racing the first race of the RCK series here in the south or not. Right now even the weekends are full planned. So I got hardly time to prepare the car and no possibility for a shakedown run... Luckily I could manage to open up a first run on friday afternoon at my hometrack in Senden and then I got the news that the race location in Crailsheim will open their doors for guests on the 3rd of october. That is a holiday in Germany. Awesome! I am really looking forward to these dates.

Yesterday Shapeways send a message and required a redesign of the armmounts. Nothing serious, I just needed to beef up the connections between the parts, but this will delay the delivery. I hope the parts arrive on time for the practice on october 3rd...

With the first run coming on friday, I used the freetime and evenings to continue with the body. I mean, I bought the wrong version of the Protoform Corvette for this livery, but still the outcome is gorgeous:



The RTR weight is 1245g with body weighting 90g.
Again, I can’t wait to drive this car 

 

Another picture. I added wheel stickers. There was the wish to use spoke wheels, but the price for tires, wheels and foam inserts was too high (nearly 50€). So stickers need to do the job.

(26. september 2018)

[Nicadraus 6757]

I followed this build in RCtech. Just amazing Kevin!

[wtcc5 5902]

@Nicadraus: Thanks 

I thought people here will enjoy the pictures too, so I will bring it over here in a shortened version and then continue to post news and upgrades when racing resumes.

[wtcc5 5902]

The first rollout with this car is already over. From 14:00 till 20:00 o’clock I practiced at my hometrack in Senden. I still can’t believe how well it went. The truth is that body and wheels are still scratch free. I had no accident or touched more than the curbs. The car ran without issues all day. It reacted well and honest to every setup change. From the beginning the balance was good. I focussed on making it more responsive and quicker in direction changes. Working with droop and roll center proved to be most effective today.






Starting with a „green“ carpet (first use this season) I could improve from a 12.371s laptime to a 11.620s. The carpet got better and better throughout the day, so my net improvement should be around 3-4 thenth. The car was easy to drive and already very good to handle. A little trouble made the front shafts as they rattled and the rear diff outdrives as they are just loosely plugged into the diff. 1-2 tenth are still on the table. I want the car be turning better with less steering input. Right now, with the 3 degree toe in, it is stuck a bit too much and I need to force the rear „steering“ with a hard steering input. And in too many corners I am at full lock, which is not my way of driving/handling a 17.5t car. I want it to start turning off throttle with a small steering input already, then control the slide with the throttle to carry the speed through the corner.

Early next week the Shapeways parts should arrive. I am also waiting for a sealed gear diff to use diff oil instead of grease. Then the practise at Crailsheim waits. I just hope the car will handle as good as it did today.

(28. september 2018)

[wtcc5 5902]

Here now some pictures of the diff build:









The build was ok. I find the o-rings to tight. So the diff outdrives already have friction. This will make it hard to differentiate small cst-change-steps... Maybe after some runs it will loosen up...


Then my long awaited track widening parts arrived:





These parts are made of the strongest plastic Shapeways offers. Compared to the normal strong plastic it feels soft - easy bendable - like a mix between plastic and rubber. The surface looks very similar, just one side looks strange, with sharp edges where fillets should be... The accuracy is a little off too. With one part beeing on spot and the other next to it 0.25mm smaller.

I wasn't sure if I should risk to use these parts already. I decided to try the front end conversion as the rear with 3 degree toe fits better than thought under the rear fenders. The first fitment:







This step really got me worried as it brought up more work than I wanted. The droop screw position needed a change, the pins needed to be shortened, then the steering turnbuckles were to short, a new shimming was necessary, new CVS needed to be installed and the front needed a new setup. Somehow I wasn't sure if I could do all that until tomorrow. Oh well, step by step, I worked my way through without running into problems.

Until... I wanted to setup the droop. The shocks were too short to allow for enough arm movement. That was new. The 5mm wider track meant that I needed to turn the spring retainer ring very far down to reach the mandatory right height of 5mm. The shock shaft already was at its lowest point. What now? The easiest would have been to use a longer lower ballcup. But I don't have one. Longer shocks are no option, too. Then the shocktower has to be lowered. The hole distance on the mounts is 6mm. To use the lower hole wouldn't work either. Then the shock would have been too long for this geometry. My solution now is a new hole in the middle between. The lower tower holes were a mission for my Dremel. The tower now sits 3mm lower and the shocks can operate in their perfect window. Drilling in this sintered plastic is a real pain. The plastic melts very fast. I was lucky to hit the marks. The result is very satisfying. These 3mm make the front look very low and compact:








It took another two hours to finalize the setup and finish some invisible detail work:





The car is ready for the practice day at Crailsheim tomorrow 

[wtcc5 5902]

I was at Crailsheim on wednesday.



It was a bittersweet day. The good news is, that the chassis was on rails after a few track based changes. I went for a 1.2mm rear anti roll bar and for 2 degrees of camber (1.5 before). This transformed the car to a tight cornering weasel. Right from the start I could go fast laptimes.





Then after these tweaks the laptime went down from 9.6 to 9.1s in the last run.
Unfortunately the last run was just my third run of the day... The second run ended early, too, after I got some sort of disorder: At the end of a short straight the car didn’t react to my steering input and went into the wall. Luckily there was no damage. Never having this experience with this car before, I checked everything, found nothing. Then in the third run it happened again, again at the end of a straight. This time my luck ended with a broken front armmount.



It was clear, that this part would not stand an uncontrolled impact like this. But I was mad because of the electronic malfunction that caused me to crash. Another guy racing the same class then came up with the solution: He experienced the same at an ETS race once, just that his Awesomatix was ruined heavily after it. It is a bug from the bec system of the esc (Muchmore Fleta Euro). The esc requires a Schottky diode between receiver and esc to protect the receiver from too much power from the esc. Up until now I ran the esc for over a year without trouble. Then again one full day of training in this configuration without any problem...
Muchmore does not sell their bugfix cable. Then my luck came back: ETS regular Alexander Stocker will attend the race (in my class  ) and promised to bring along the cable  Very cool!

So after that damage I was forced to return home. Hours later I was informed that my 9.1s was still the fastest GT-Sport lap of the day.

[wtcc5 5902]

Finally I can report how the first race with my TT-02 conversion went.



The car left a lasting impression, that is for sure! After I set the fastest time of the day on wednesday, I didn't touch the settings for sunday. I arrived early at the track for practice and trying to get into a rhythm (my weakness  ). It went pretty good. The car had a little bit too much steering for my liking. The track got a lot more grip than wednesday. Alexander Stocker was really nice and gave me the Schottky Diode for my esc for free. With that I didn't had one interference the whole day.

For qualifying I was already assigned with the fastest drivers. And it was close. Of course Alexander showed his talent, by beeing not only two tenth faster than all of us (8.8s), but also a lot more consistent. He regularly lapped us twice. Behind him Michael Schulz, Joachim Altenhof and I were only seperated by a few tenth on every run. While my fastest laptimes were always faster than the rest of them (9.0s compared to 9.3s), my consistency was terrible. The curbs were forbidden territory, because one slight touch meant that the car rolled on its roof. This happened several times to me and ruined my qualifying. With a little more nerves the second grid position would have been possible. I had to settle for fourth (of 18 starters) instead. Still no reason to be unhappy. On pole was a ETS-A-finalist regular with a full tuned TT-02, a member of the club with his (full?) tuned TT-02 and one German champion (one guy even said he became European champion once). So that result seems to be ok for someone who didn't do a race and very seldom drove an RC car since April.





The races ressembled the qualifying with one exception: After getting involved in start crashes in all heats, I had to catch up from last place again and again. In the first raced I fought back to fourth place, then I became third in the second heat and last in the last heat because of the damage that was caused in corner one. Again in the first two heats my fastest times were the closest ones to Alexander (always two tenth behind). My final position was fourth overall.

So that was bittersweet, but with a sweet repercussion: I already sold three of my conversion sets for the TT-02. Which comes as a total surprise. After the race I had two potential customers, that both bought the conversion parts yesterday. Today a third one, bought the parts without having seen my car in real live. That is kind of cool 

(10 October 2018)