“Scale” racing revisited

Some of the best racing I have done has been with “scale” RC cars, and in particular with the Tamiya Mini.

Unfortunately, the opportunities to do this can be pretty limited. My local club (Bristol Model Car Club) usually has a heat of Minis, but a lot of clubs don’t, and it is rare to find a regional or national series that supports scale racing.

So the Iconic Cup was something I just had to get involved in…

TT-01E.jpg

The series is effectively a time capsule dedicated to the Tamiya Eurocup which last ran circa 2005*. This means that only Tamiya on-road cars from this period are allowed to race.

Unfortunately I don’t own any cars from that era any more. Rather than buy an out-of-production car (and all the spare part issues that could cause), I went for the only car on the permitted list that is still in production – that Tamiya TT-01E.

The TT-02 replaced the TT-01 a few years ago, but for some reason Tamiya have revived the older chassis for their MAN racing trucks, and for this “Diebels Alt” Mercedes 190E which is quite easy to buy on eBay from Germany – mine arrived within a week.

The hop-ups that are permitted are limited in scope, but the rules are not as strict as the old Eurocup. I have all of them! The new purchases are pictured, and I will be choosing some oil dampers from my spares box. I’ll update the blog once the build is completed.

I have owned a TT-01 before, and they are a surprisingly good to drive. Considering the limited power from the Sport Tuned motor, I’m confident that my car will keep pace with the more adjustable chassis in the class. We’ll just have to see whether my driving is up to scratch…

*An honourable mention needs to be made for the Super Production Cup which continued the spirit of the Eurocup for a number of years, and which I entered in 2011 and 2012.

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TRF201XMW – The build – Completed! And first race report…

I mentioned earlier that fitting the electrics and painting the body takes me a long time, so there are not so many pictures here because there is not much to say, but it was several hours work for me to get from the rolling chassis to the finished car!

The first couple of steps in Bag E are fitting the motor and servo. The motor mount doesn’t have a very large range of gearing options, with a maximum of a 24T pinion to mesh with the kit 79T spur, and Tamiya’s only option is a 77T spur. I suspect that B4 spurs will fit. The motor cover doesn’t give much space for the pinion either. The gearing options are fine for a modified motor (I run an 8.5) but might need some thought to get a good ratio for stock motors (which are not generally run in the UK with buggies). Tamiya supply two lengths of screw to mount the motor with, I used the 8mm ones, just make sure that they don’t make contact with the internal parts of the motor when tightened.

The gear cover does not have a great deal of room under it for a big pinion
The gear cover does not have a great deal of room under it for a big pinion

Next step is fitting the servo. I treated myself to a new low-profile Futaba BLS551 – and it was a good thing that I did as there is no way I could have got my (large) electrics in with a standard servo! While I was trying to set the servo up, I realised I wasn’t happy with the standard installation. The main issue was not being to get full lock even at 120% EPA (the maximum with a Futaba radio). This is a problem I have run into quite often. So, I made a few modifications. I won’t share them right now, but when I have a solution I’m totally happy with, I’ll post an update.

Initial servo installation - but I have made some changes since then...
Initial servo installation – but I have made some changes since then…

Last jobs are getting the electrics in and fitting the body.

I’ll talk about the body first. It’s low and narrow with a mid-cab design and a “Le Mans”-style fin. Not a bad looker overall. But it doesn’t give you much room for the wiring, perhaps because it is from the older XR (the sticker sheet is also from the older cars). Read the manual carefully when cutting it out, as part of the rear needs to be left to cover the motor.

No XMW stickers here! Have to make do with the stickers from the XR and XM conversions.
No XMW stickers here! Have to make do with the stickers from the XR and XM conversions.

In order to fit the body, I chose to run the wires off the side of the ESC and along the side guard. They then need to  be stacked vertically along the rear battery post and onto the motor (I use a Speed Passion 8.5 which has the plugs on the end). My original wiring took the wires over the top of the battery post but there is not enough room. There isn’t a great deal of room for the front battery connector either – I use low-profile connectors with the wire coming out of the side and it still rubs on the body. It may be possible to run the wires right down the middle of the car instead, but it wouldn’t look quite so neat. Because my ESC and receiver are quite big, the unused hole in the side guard got in the way of taping them to the chassis. My solution was simply to fit a double layer of tape to lift the electrics up, this worked well and may also help with shock absorption!

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The first race

First race was at an indoor multi-surface track. I chose to go with the kit settings (which I didn’t expect would be suitable but you have to start somewhere), Yellow Schumacher LP Cut Staggers on the front and Yellow Schumacher Minipins with the U6734 insert on the back, mounted on Associated wheels (yes, they came straight off my B4!). Ride height was 21mm all round. Gearing was 23/79.

I also checked the weight distribution. Out of the box with no extra ballast, there was a really good balance from left to right (only about ten grams in it), with about 600gms on the front axle and 1000gms on the rear axle, giving a weight distribution of 37.5F/62.5R at 1600gms. This compares to 34/66 at 1600gms on the B4 with the same tyres and around 40 grams ballast on the front axle. A big difference!

On the scales - 37.5F/62.5R - a big difference compared to the rear motor B4.
On the scales – 37.5F/62.5R – a big difference compared to the rear motor B4.

On track, the car was very, very good, which took me by surprise. In the first round the tail was a bit lively on the slippy sections, but as the grip came up and I got my eye in, that stopped being an issue. Jumping was really good, the landings were really plush, and the balance through the corners was good, albeit with a little mid-corner understeer on the tight hairpins. I leaned the front shocks in one hole to try and address this and it seemed to make a small improvement. The motor seemed to lack a little rip at the bottom end, so I increased the punch on the ESC. Overall, a real pleasure to drive.

The car did go a bit funny at the start of the third round and started spinning unexpectedly in some corners. I thought at first that it may have been the diff or my sensor wire. The car improved after a minute or so, which coincided with a lump of stringy fluff coming of the back end of the car… I checked the gear diff after the race and it hadn’t lost any fluid, and the sensor wire was secure, so I think the bad handling was simply down to picking up the debris.

I was rewarded with a grid position at the back of the A-final, and after a really close and fair race I managed to finish in third place. Hard to say how much quicker the car was over a single lap than the old B4, but it was definitely easier to be consistent. Whereas with the B4 I would have to work hard for 5 minutes to keep it going in the direction I wanted it to, invariably resulting in a couple of costly mistakes per run, the 201 was much easier to drive, and I could have my 10-lap consistency within a couple of tenths of my fastest lap. This is much closer to what I can do with a touring car and very satisfying!

I’ve ordered a few tuning parts (don’t you always?) so I can replicate Satoshi Maezumi’s high-grip setup (if I want to), and I can also try a few changes to the kit setup to get a bit more steering. I’ll keep you posted as things develop, but it has been a very good start!

Dave

CWIC 23/2/14 – Blinky

I’ve been struggling with a lively rear end on the TRF418, this makes it quick when the conditions are right but tricky when they are not. I experienced both traits today.

The car was tricky in the first two rounds (and there was a lot of contact as racers got used to the difficult track), but in the third I got a clean run and ended up third. I added droop for the fourth round and the car was terrible with far too much steering, and a partial return to the round 3 settings in the first final (for which I qualified 5th) wasn’t a success (finishing 7th). Widening the front end, reducing the steering lock and making the expo milder helped to make the car more driveable in the second final, and a tidy start combined with others’ mistakes allowed me to finish 2nd after a really good late race battle. The slim hope of stealing a victory this season lives on!

I’m debating picking up a few of the common tuning parts to try a wider variety of settings on the car to make the tail less happy. Although outdoor season starts soon which has a completely different style of track and surface.

CWIC 23/2/14 – Mini

I chose to challenge myself today and see if I still had the pace to compete in Mini a couple of seasons after my championship win. Within half-an-hour I remembered why I don’t like running two classes in a day – too much rushing around. Not only do you forget to charge batteries, you also forget to race!

The track was very twisty – a layout that I didn’t like earlier in the season which was even trickier anti-clockwise with a particularly nasty right-handed kink that led immediately into a left-right chicane.

I knew before I started that they newly rebuilt diff was too loose, and this was demonstrated by the handling in the first round. Although I finished second the car was diffing-out through the fast sweeper and hooking into the corner at the end of the straight.

For the second round I exchanged the #5,000 oil for #100,000. The car was much better in and out of the corners but the trade-off, as ever, was straight line stability. The car was just about driveable though, and I TQ’d the second round and just missed TQ in the third.

The Blitz Mini Jazz shell is quite tall and the rest of the top drivers were using the Mini GTI so I followed suit. Round 4 was littered with mistake so couldn’t take advantage of any advantage the lower shell may have offered and would line up third on the grid.

The first final started well and I was second after a couple of corners. I kept the pressure on the leader and waited for a mistake which came quite early, although I rolled off the track towards the end and was lucky to have built up enough of a lead to stay in front until the end.

For the second final I went up to #450 oil in the front and down to the Yellow spring in the ear. This may have helped to make the car a bit more stable and I ran a similar final to the previous one, moving up to second through the first corner and pressing the leader until an opportunity to pass presented itself. This time I kept the car on the track and took the win.

So it seems that the M05 still performs well, I’d probably try #30,000 in the front diff next time, but I won’t be running Mini again at this CWIC- too much stress!

Today’s CWIC

Decent result at the CWIC today, perhaps my best of the series, and a better day with the TRF418.

Ended up qualifying 6th but was a lot closer to the front of the pack, in fact I had a shot a TQ in the last round but made a couple of mistakes with an empty track around me. Finals ended as a 6th and a 4t which was about right, I was pressing for 5th in the first one and defending from 5th in the second but didn’t have the extra something that the top few had today.

Before the meeting I had rebuilt the rear diff with the red Tamiya o-rings. These seem to have a much better seal, but also add a little more friction. The car was a real handful in the first round, a few tweaks to the steering rates improved matters, but the car was still sliding the back around in the second round so I went down to #1000 oil in the rear diff which was a big improvement. #2000 was good with the black rings but too thick for the red.

The first round also resulted in both spool blades breaking, there was no way I could cope with this many failures (averaging more than one every other race), so I begged a fellow racer to let me buy his spare set of Roche blade-free outdrives and these performed faultlessly throughout the day. I’m pretty sure I have a reliable platform for carpet racing now, I just need to focus on the driving.

I made a couple of setup tweaks during the day, fitting a slightly softer rear spring and standing the shocks up. The car was feeling better as the day progressed and attracted plenty of compliments but I suspect the improving track conditions were a significant factor. We’ll see how it goes at the next round.

Final comment is on the Protoform shell. I’ve been running Blitz shells for the last couple of seasons and I have to say that Protoform’s material is much more fragile, the front of the shell is covered in tiny cracks after only two race meetings.

Dave

First race meeting with the TRF418

Gave the TRF418 its proper race debut at the CWIC today.

First run was a bit erratic, immediately decided to swap the kit springs for something more conventional (ARC White front and Yellow rear, equivalent to HPI Pink/Silver) and to thicken up the rear diff to #2000. I was disappointed to find that the rear diff was already almost completely empty of fluid from just sitting around. This is a bit of a concern as the ARC diff never leaked once. I’ve orders the red o-rings (#42259) and will have to find a way of making the gasket form a better seal too.

The car was greatly improved straight away in the second round although quite edgy on turn-in, as the tyre came in the car was quite driveable and I was 6th in round (I think) from a field of nearly 50 in 17.5 Blinky.

I tried the warmers for round 3 but it didn’t make much of a difference, and as the track grip came up the rear end became more locked in, perhaps too locked in. I messed about with my steering linkages a couple of times during the day because I wasn’t convinced I was getting even steering both ways.

For rounds 4 and 5 of qualifying the car felt pretty good, but as ever I just lack the ultimate pace of the top drivers in the class so qualified 7th. Before the finals I dropped the front end down to ARC Yellow springs too. Results were a 4th (after a lucky start) and a 9th (after one of the biggest first corner crashes I have been in, which knocked the fan out of the car and dislodged the sensor wire, fortunately a marshal noticed the problem and I carried on, a lap down). The car itself survived the shunt and drove just fine.

Apart from the diff concerns (the #2000 didn’t seem to leak excessively during the day), I also broke one of the blades on the front spool, and also broke a 3Racing replacement. I’m weighing up the benefit of switching to a non-bladed spool outdrive (made by Roche). The Lipo mounts were also a pain, because my decision to trim them meant they were prone to twisting around.

General driving impressions was that the car had a lot of turning ability but with a stable rear once the grip came up. A smoother drive than the ARC which always had an edginess indoors, However I couldn’t say it was any quicker as I qualified where I would normally qualify and finished where I would normally finish! Perhaps more consistent though, managing 0.3s difference between average and best in some runs whereas the ARC was rarely below 0.5s. The full-size LiPo may well have helped to stop some late-race power fade too.

Dave