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ThunderDragonCy

Project RR-03Ra - Converting a TRF201 into a rally car

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14 minutes ago, ALEXKYRIAK said:

Awesome mate, what an adventure. Very happy for you and for how it’s turned out, especially all the custom modding and experimental stuff. Very inspiring. Hope to see a longer video on that larger gravel area you’ve shot videos on before :) 

Thanks dude! Really pleased the stiffer springs sorted it as it was a bit sketchy to drive yesterday. Will be interesting to see how the brushless will change it. Unfortunately that gravel car park has really big stones. The DT03 had barely enough clearance so this would have no chance. Going to take it to the track day in a couple of weeks and see how it runs. There is supposed to be a rally stage there now too. Will see if I can find a helper to film. 

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You know of a track with a rally stage? Where is this wonder pray tell?

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58 minutes ago, ThunderDragonCy said:

Its just so cool.

Agreed! It looks great. The chassis work is brilliant too, it’s been good to watch it develop. 

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33 minutes ago, TurnipJF said:

You know of a track with a rally stage? Where is this wonder pray tell?

Robin Hood Raceway. Been a few times to the astro but never seen the rally stage, but there is one apparently

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2 hours ago, ThunderDragonCy said:

Robin Hood Raceway. Been a few times to the astro

Hoping to get down there this year, bit of a trek, but the track looks to be worth the effort! 

The car looks perfect!

All your efforts have not been in vain.👍

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On 3/20/2019 at 9:30 PM, ThunderDragonCy said:

Amen brother! RC cars are for driving and tinkering with. 

Lies! 😂🤣😂🤣

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Also...

 

Epic build matey. Very impressed. Looks ace. Love the engineering that went into it. Great project

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Looks like it runs well and you’ve kept just enough rear grip too!  The question is how well does it fly? 

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1 hour ago, Juls1 said:

Looks like it runs well and you’ve kept just enough rear grip too!  The question is how well does it fly? 

I will see in a week or so when I run it at the track. 

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Just catching up with this thread again...  Great job on the Ford shell and the chassis!

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Couple of little things this week. I added the night stage light pod, because rally

20190411_124858

First time using Shoe Goo. It's amazing! So much so that it helped the second addition

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Some great advice from @speedy_w_beans and @TwistedxSlayer on my question about these. Ended up getting a 72mm Tamiya bumper, sticker the unmolested end to the shell with Shoe Goo having trimmed the narrow end to be just larger than the gap so the shell presses the foam onto the bumper of the TRF201 chassis. Had to trim the sides a little as well to clear the front wheels at full lock. Final piece of the puzzle arrived today in the form of some more sticky backed velcro. This keeps it nicely stick to the chassis. Ran it in the street at lunch time and the shell is much quieter. Really looking forward to running it at the track this weekend!

Finally, been wondering about a cockpit set. As I'm using the buggy shell as a chassis cover the thought occured that I could just bolt a cockpit set to the roof of that. Anyone got any advice on this? Doesn't have to Tamiya parts. Do other brands make cockpit sets?

20190411_125412

 

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1 hour ago, ThunderDragonCy said:

Finally, been wondering about a cockpit set. As I'm using the buggy shell as a chassis cover the thought occured that I could just bolt a cockpit set to the roof of that. Anyone got any advice on this? Doesn't have to Tamiya parts. Do other brands make cockpit sets?

 

Great work! Going to get some of that goo for some shell repairs I need to do. I hear it is great combined with ‘drywall’ tape.

This is the TB-01 solution - two screws with washers secure the cockpit set to the lexan cover. Could you use or cut down a Tamiya rally cockpit set? 

A1A212BA-8801-4000-BC73-3BB7F8BDDC66.jpg

 

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Little update on the RS200. Firstly I ran it at the track during the Tamiya junkies track day a couple of Saturdays ago. It ran great on the national astroturf buggy track! Jumped pretty well, gave quite a good account of itself. Had to drop the front ride height by moving to the outermost holes on the front arms and needed to stiffen it up too as it was rolling too easily. I was just reacting that day but ended up with the DF03 setting spring set gold springs front and rear which are around 2.7lb rear and 4.4lb front (it seems most buggy size springs are sold in lb ratings). Tried a few different springs after just having some fun driving it in the street and seeing what it was doing and ended up with the DF03 black soft rear and DF03 silver hard front which are around 2.3lb/4.5lb. Works nicely now, with decent turn in but plenty of rear traction.

Worth noting that these are still way softer than the 53163 on road rally springs tamiya offer. Even the softest red spring on those is around 5lb rate, with the stiffest being 7.1lb. That said, apparently the XV01 Long Damper spec specifies the TRF501 front spring set which is 3.17lb to 3.8lb rates so maybe I am not completely out for a long damper rally car with an odd weight distribution. 

Finally, doing all this tinkering I ran an entire pack through the car and I am so impressed with this random 27t motor. I compared to to a silvercan and it is WAY faster. It must be one of these stock class motors you can buy. Clearly all 27t motors are not equal! It's pulling an 8.7 FDR which isn't super high but it's as zippy as I would like, the motor gets hot but not burning and I got about an hour of running out of a 4000kv shorty Lipo. What's not to like? I am think brushless is postponed for a while. 

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On 4/1/2019 at 10:30 PM, ThunderDragonCy said:

Robin Hood Raceway. Been a few times to the astro but never seen the rally stage, but there is one apparently

There is a newly set up rally club in chesterfield too. Not been down though.

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22 minutes ago, graemevw said:

There is a newly set up rally club in chesterfield too. Not been down though.

Really? Can you pass on the details please? 

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9 hours ago, ThunderDragonCy said:

Ta. Not far from me either. Unfortunately they have weirdly strict rules about bodies. I couldn't run this because it was 4wd in reality, but on a 2wd chassis here. Can't be bothered doing a whole RWD body just for them. Seems pretty self defeating. 

Yeah, i read the rules before and thought it was a little strict. You could run in open class i think? I was tempted to build a car for it, might pop down and see what the set up and people are like. 

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8 minutes ago, graemevw said:

Yeah, i read the rules before and thought it was a little strict. You could run in open class i think? I was tempted to build a car for it, might pop down and see what the set up and people are like. 

Let me know what you think. I couldn't see any 2019 dates. 

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I noticed that too. Possible they stopped due to the rules meaning people havent gone! Or maybe they just havent updated the website.

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Had a good long run in the street tonight. I love the lighter evenings! Also nice to have something I can razz around with without going anywhere. 

Couple of minor tweaks. After getting the springs and handling pretty sorted last week, it seemed to be riding low at the rear so I added some thick preload collars to the shocks. Made much a difference! Turn in better and understeer much reduced, but still with that nice balance. Took them off again to check and it's definitely better with. Apart from a quick spring swap in the ball diff to fix it (it seemed to be barking despite being fully tight, so I tried a spare spring leftover from my DB01R diffs, much better) I just drove. Really enjoying it. Wondering about trying brushless power now it's so sorted. 

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Well it all went to pot with this after the last post! The rear tyres wore out and evetything i bought to replace them (they were ebay special rally blocks) were considerably worse. The schumacher SST rally yellows have been ok but they are very small. I bought some absima road tyres and wheels. Very little grip and shattered a wheel on first run sliding into a kerb. Junk! Got the pirelli style rally tyres. No grip at all! Got tamiya semi slick tyres. Like driving on ice! Rally blocks it is then.

Rear was still pretty wayward so i have been chasing the setup a bit. I have put a 3mm spacer in the front shocks and 7mm rear (net shortening of 4mm as i took the o rings out). Gone to stiff front road springs from some old absima shocks, and softer rear springs from the cva 50520 set. Added some preload collars to maintain ride height and minimise droop. This has improved braking stability. Finally, i saw the TRF201 XB front suspension block on offer so i got that. As well as being aluminium, it increases toe in at the rear to 4 degrees from three. All these things together have got it running really nicely again. If you are going to do something like this, lots of rear toe in! 

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RR-03Ra has been languishing recently. Had a lot on with the TA06, but learnt loads. I also wasn't completely happy with the handling of the RR, and it was just so so soft at the rear. So, some plans to sort it. 

Biggest thing which has helped traction is a gear diff. I am selling my TRF201, so i swapped the ball diff transmission over to that and the modified version for the kyosho gear diff over to this. This gives much better and cleaner traction coming out of turns, but it's spinning away the inside wheel a bit so i need to get the diff open and check the oil level. I have 3000cst and 10000cst oil so I will start light and see what happens. 

Second thing : Ride height. After seeing how sensitive to ride height and droop settings on road cars are with TA06, i have asked around about what kind of ride height I should go with. It was well over 20mm before - higher than my astro setup TRF211! Despite shortening the CVA shock and restricting it's travel, it had super soft rear supension with loads of droop which gives loads of weight transfer under braking, which you don't want on 2wd with only rear wheel braking. And to try and control the rear I had super stiff front with virtually no droop, which gives no weight transfer rearwards on throttle, which you also don't want on 2wd! After re ading around a bit I decided I wanted around 15mm ride height, with less droop at the rear. I pulled the shocks off and put lego blocks under the rear at around 19mm and front at 21mm. This would allow less rear droop and still even out the ride height. I measured the eye to eye distance from mountings to arms. On the front the widest arm hole to inner tower hole is a perfect (for mini cva) 64mm. At the rear the outermost tower to inner arm hole was 85mm. I read that upright rear shocks and inclined front gives the easiest handling car. 

I was also convinced that the different size and and length CVA shocks front to rear was making it hard to balance out. On road cars have same shocks all round.

The IFS layout on my TA06 gave me an idea. This uses regular super mini shock body with rear buggy shock piston rod and a plastic travel restrictor to give same spring and travel as a regular shock, but reaches the rocker. The piston rod in the rear shock is 49.5mm. The regular front mini shock rod is 33.5mm so i have 16mm longer shock (either 80 or 86mm depending on eyelet) and with the 7mm spacer on the CVA sprues doubled up i can take most of that back so i end up with 17mm stroke instead of 15mm on the front. Close enough. So, i ordered up some front CVA shock bodies. They are only a couple of quid. The other advantage of using 'front' bodies all round is its possible to use on road or front buggy springs all round to even out spring rates, and identical damper pistons to even out damping. As an added extra I used the spares 3 hole TRF off road pistons from my DF03 alloy shock set. Nice! 

20190831_165755

I built them up 400cst oil rear, 700 front and had a play with the springs.

The 53163 on road/rally springs were too hard. Due to the previously oversteery handling, I went soft red rear, hard blue front. The car was also (unlike previously) giving a lot of understeer and was cleanly getting traction on throttle. I swapped the springs front to back but it still wasn't ideal and mot giving much droop at all. Even the soft (for on road) 53163 set used here are over twice as stiff as buggy front springs. 

A started adding TRF buggy springs. I have the full set to choose from as i have both the TRF201 set (very soft brown, black and green) and the TRF501 set (more usual red, yellow, blue). I have ended up with yellow rear (one down from stiffest) with a 2mm preload clip. Front I am running super soft brown TRF201 front springs, no preload. This is giving 15mm ride height rear, 13mm front. I will run this for a while and maybe add a preload clip to the front to even out the ride height. 

20190831_165806

What this also gives is lovely soft, supple suspension but really lovely handling. You can see the front tucking into the wheelarch on corners. Exactly what I always wanted from this! 

Stance is perfect now too. 

2019-08-31_07-35-12

 

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