131 replies to this topic

[Mad Ax]

UPDATES!!

I haven't bothered to update for a while since my posts were almost becoming a carbon copy of one another. But the winter championship is now underway, so my focus has returned to going as fast as possible and getting myself as high up the FTD sheet as possible.

The opening championship night went very well, my car was on top form and I finished 2nd overall, but was waaay down on last year's champion, who was several laps ahead of all of the rest of the field.

The second championship night was just over a week ago, and my car went from good to terrible in one night. I wasn't too far off the pace in race one, but by the end of the night the motor had given out once again. Exceedingly hot motor temps seem to destroy brushes and wear the comm. I was able to take the entire track at full throttle. It was my worst finish in ages, way down in 6th place.

Yet more motor problems encouraged me to give up on the ancient brushed Trinity and invest in a Fusion Exceed Sport 13.5T system, which is what the current fastest driver is using. Apparently several other members of the club have recently bought the same system, so it's almost becoming the control package for the senior touring class.

Last night's race was non-championship, so it was a good chance to see how well the brushless motor performed. Other drivers on the same system are using a 6.5:1 gear ration, but I seem to have lost my 70T spur, so the closest I could get was 8.19:1 using some old .4 gears that I had in my kit box. I've ordered a new 70T spur so next week I should be able to get right on the 6.5:1 bubble. The motor wasn't overly hot after the end of each race, so being wrongly geared wasn't doing any damage - I just noticed that I had a bit too much punch coming out of corners and was spinning the car too easily.

By race 3 I'd got the hang of the extra power, although the exceedingly tight track made it a real challenge.

For ages I've wondered how the other top competitors manage to get through the tighter sections with such precision - their cars can change direction so much faster than mine. I've often thought it must just be down to chassis setup and driver skill and left it at that, but last night, while parked on the start line waiting for the race to begin, another driver and I were turning our wheels from lock to lock as fast as possible. His moved lightning-fast, mine were... erm... well, sluggish would be a generous description.

The servo is a Futaba, probably from one of the basic radio kits that I've acquired with package deals over the last 6 years. It looks like it really isn't fast enough for racing. It looks like I'll have to put my hands in my pockets again for a faster servo!

Another top racer (currently on sabbatical from racing while he plays at being mechanic / pit chief for his skilled young son) has offered to lend me a Spectrum transmitter for a few weeks so I can get the best out of a faster servo - apparently if I try to run it on the basic Losi transmitter it will turn too fast to control.

It looks like my tyres are also past their best - I've been advised to replace them. That said, the current championship leader says he's been using his tyres for 2 years and he's still sticking to the track better than me, so I can't blame the tyres entirely!

The third championship round is next Monday, and I'll hope to have my gearing sorted and have a faster servo installed to get the car as close to perfection as possible. Also got some CVDs on order to try to reduce the problem of the dogbones trying to pop out on full lock, which is what is causing a nasty judder in the front suspension on some corners.

Final bit of great news - my shell has been painted! Will be cutting / mounting / decalling it tonight, so watch this space for some updated pics of my new livery

[Mad Ax]

Piccars of the new shell!!

http://www.tamiyaclu...a...86&id=15729

This really did look so sweet on the track this week. I can feel the downforce from the spoiler as well. The balance of the car has been upset a little by the new shell, but by the end of the night I was getting the hang of it.

Mondays race 1 was probably the best race I've ever had - 26 non-stop laps of mistake-free accuracy. I still finished 4th behind the club champion and two other very good drivers, and I failed to improve on my time throughout the night (too many mistakes in races 2 and 3) but overall it was a good meet.

Haven't seen a championship standings sheet for a while, so I'm not sure where I lie overall, but will see if I can get an update at next week's non-championship meet.

[Mad Ax]

I thought I'd drop in for a quick update after last nights rather abysmal performance.

I knew something was wrong in the practice. The car had absolutely no front-end grip. Going into slower corners it was like it had no tyres on. The track was a pretty tight one, and there were some corners where I had to slow to a crawl or do a three-point turn to get through. I softened off the front shocks to try to get a bit more grip, but it didn't help for race 1. However, race on, I noticed that my new shell was grazing the carpet. Since the slower corners all had a number of bumps in the carpet, this was looking like the most likely culprit for my front grip problems.

Race 2, and shell remounted, I expected better results - but didn't get them. The car was almost uncontrollable, right up to the point where it started grip-rolling. HUH?? How can a car go from no grip at all to enough grip to grip roll..? Another racer (the fastest on the night) drove my car for a while and told me it was "bloody horrible."

Back in the pits, I took a look at the steering, and discovered the TowerPro 955MG servo was bouncing at the end of its throw and giving very innacurate steering, as well as failing to give full extension. The original Futaba servo was quickly swapped back in, and I was back out on track for the final race, with one chance to redeem myself from a thoroughly disappointing evening. Sadly, it wasn't to be. Once again, the steering started to lock out on full lock, resulting in my car being stationary for several laps. The overal result was a very poor 10th place, below people I have been consistently beating for the last few weeks. Lucky it wasn't a championship night!

The steering lock-out problem seems to be caused by the driveshafts riding out of the cups on full lock. I've now bought two sets of CVDs but neither fit my IFS front-end, so I'm almost at my wits end with this car :-/

I've got a faster servo on the way, as recommended by the club's fastest racer, for only £27 delivered. I wasn't going to spend any more on the car but I guess I'll have to plump for yet another set of CVDs...

On a lighter note, I'm currently standing 2nd in the championship, but only by virtue of being one of only two of the top-heat drivers to have contested all three rounds so far. I doubt I'll hold onto that place once there's been enough rounds for everyone to have scored their best 6 results. A lot of faster drivers have joined in the early part of the championship, with yet more promising to enter the touring car class soon, so I'm currently in danger of losing my spot in the top heat.

Fingers crossed I manage to get some CVDs for next week and have a better result for my championship bid

[Percymon]

Oh dear - just when it looked like you were finding some consistency and improved set-up.

Check weight distribution too, especially since you moved to brushless set-up.

[Mad Ax]

Good point Percy. The brushless motor and new shell has probably changed the balance of the car quite a bit. I definitely feels like it's missing some weight over the front end - the Tamiya 350R shell was quite a bit heavier, which might have helped force the front end into the carpet.

I'm sure I'll get the balance back, I guess that's the problem with changing shell, motor and servos right at the start of the championship. First thing is to fix the obvious problems - new CVDs and Savox servo are on their way, I've also been loaned a proper Spectrum transmitter with full adjustability so I can hopefully tune the steering in better. I'll go back to the chassis setting I had before Monday for the next meet, so at least I know I've got a good base setting when getting the servo tuned in.

[Mad Ax]

Got a happy update from last night's racing. I arrived at the venue with a newly-fitted Savox servo and hybrid CVDs to speed up steering and cure the locking driveshaft problem. For £27 delivered, the servo has probably given me most performance gains per pound since fitting proper tyres. The car now actually steers. The servo seems to have more throw than the basic Futaba that it replaces and it gets there so much quicker.

In practice the car was horribly twitchy, steering way too fast, so I sat down with the handbook for the borrowed Spectrum handset that I've been loaned and tuned down the exponential on the steering channel. A race buddy gave my car the once-over and decided that both front and rear diffs were way too lose, so I used the rest of the setup time to tighten them right up. The front diff doesn't feel very smooth at all now, maybe it's been loose for too long and needs replacing, but I tightened it up so it's almost a spool, which my race buddy seemed to think was about right.

I got a little more practice time, in which I found the car had gone very tail-happy, so I turned down the punch on the ESC and adjusted the expo on the throttle too.

Race 1 didn't go so well. I was getting in to a rhythm after a couple of laps when I clipped a barrier and everything stopped. I still had steering, but no power. I had to retire to the pits and it took me the rest of the race to figure out what was wrong: tuning the expo on the throttle had altered the centre point on the transmitter, so the ESC wouldn't initialise. I guess hitting the barrier must have made it cut out momentarily and when it came back on it went into failsafe. A quick recalibration of the speedo and I was ready to race, but it was too late to get back on track.

Race 2 was better. The car ran without a glitch, although the back end was still too lively. I was trying to feed on the power nice any early but kept on oversteering out of corners and having to back out to regain control. A few times the car oversteered back enough to go nose-in to the inside barrier, and without a reverse I lost time waiting for recovery. At the end of the race I was 4 seconds down on the fastest car from the B seniors, which is too close for comfort considering how badly I performed last week.

Before race 3 I decided to slacken off the rear diff a bit. Maybe some people prefer them tight, but it doesn't seem to suit my style. Immediately I found a rhythm in race 3 that I hadn't managed to capture all night. At last I was beginning to keep up with the top 3 cars - I still finished several laps down on the fastest time, and at one point lost my rhythm and had a lap of barrier-bouncing, but it was a definite improvement. I finished 4th overall, which isn't a bad result for a championship night.

I don't think there's any more championship points up for grabs before Christmas, so it's a good way to end the year. Next week is open racing so I'll be back to improve on my form and - hopefully - leave the car alone. The following week is caravan racing, so I have to get some bits out of the loft and see what I can build...

Have fun peeps

[TenzoR]

Generally your rear diff should be smooth.

The way I understand it is, you want your car to rotate at the rear and you want the front to pull your car out of the corner. This means the rear diff has to help your car rotate and your front should rotate less (e.g. spool effect) and pull your car out of the corner. Almost like a pendulum swing but with more control.

I would recommend gear diffs as they have less maintenance, so you set it and forget it. I've been using dual gear diff for a while and it's been fantastic. Every race, all I needed to check is the steering blocks and the C hubs to make sure there's no rips or tears.

If you are oversteering, instead of playing with your radio, try to get more mechanical grip. Softer rear spring, more droop in the front (allow weight to transfer from Front to Rear), more rear toe, damper position.

The TA05 (belt) should have a lot less oversteering problems than my TB03 (shaft). Hope this helps