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XV-02 Lancia Delta - Tamiya Rally Review - Alejo's Project Thread

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Out of curiosity why do people add the bodyshut lines? Do you not think it takes away the scale and makes it look cartoonish?\

Regardless that’s absolutely stunning!!

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38 minutes ago, Kpowell911 said:

Out of curiosity why do people add the bodyshut lines? Do you not think it takes away the scale and makes it look cartoonish?\

Regardless that’s absolutely stunning!!

To my eyes, the panel lines make the body look far better. Without them they tend to look toyish and without detail. Example of the same body with and without lines (not my cars, linking photos found on the net):

bil-tamiya-porsche-911-gt2-ta02sw-84399.

toplarge.jpg

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3 hours ago, OoALEJOoO said:

To my eyes, the panel lines make the body look far better. Without them they tend to look toyish and without detail. Example of the same body with and without lines (not my cars, linking photos found on the net):

bil-tamiya-porsche-911-gt2-ta02sw-84399.

toplarge.jpg

Sorry, and I know it's subjective, but of those 2 I think it looks better without the panel lines.

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1 hour ago, Elbowloh said:

Sorry, and I know it's subjective, but of those 2 I think it looks better without the panel lines.

Im of that opinion too, the panel lines make it look like a render or a prototype. Maybe if they were thinner? I dont know. 
 

 However, @OoALEJOoO I appreciate your reply and Im extremely envious of your abilities. That looks absolutely amazing!

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Running Review

Finally got a chance to run the car today. Well, it actually was the second time I run it (I replaced the Silvercan with a Torque-Tuned, more on that later). Before writing a little bit on how it behaves, it would be the perfect opportunity to discuss it's handling among all my other TT rally cars and the legendary XV-01.

FordEscort_22.thumb.JPG.8b716e035fa9a3e372eab7a9c305aca4.JPG

From left to right:

  • XV-01 Toyota Celica
  • TT-02 Audi Quattro
  • TT-01 FWD Datsun 240Z
  • TT-02 RWD Datsun 240Z
  • TT-02XV Ford Escort

Quick introduction only. I'll find more time for a short review in the next few days!

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Tamiya Rally Review

Over the years my Tamiya Rally RC collection has grown to the point where I think I have a sample of most of Tamiya’s ongoing readily-available Rally cars, plus a few modded builds. The hands-on experience of building the kits is great, as well as detailing bodies and cockpits. However, by far my favorite part is running the cars. Nothing beats seeing the car in action and understanding how each chassis feature, geometry and setup contributes to the general feeling. In a way, it’s like engaging in motorsports, but in 1/10 scale and probably at 1/1000 of the cost!

Rally cars are fantastic bashers. They can run on most unprepared surfaces that are almost readily available everywhere. For the modeler, their scale look is fantastic. For the motorsport enthusiast, iconic liveries are either available from factory or easily reproducible. For the wallet, they have a fun/cost ratio that is hard to beat. They are, on most cases, tough and hard to break.

Instead of just reviewing the recent TT-02XV, this would be the best opportunity to talk about the entire fleet! The following posts will be a recollection of my observations and experiences with each of these vehicles:

RallyReview-01.JPG.8e0aba003227aab5611b8cae575535a5.JPG

  1. TT-02XV Ford Escort
  2. MF-01X Hornet Beetle
  3. M-06Ra Mazda Miata
  4. XV-01 Toyota Celica GT-Four
  5. TT-01E FWD Datsun 240Z
  6. M-05Ra Suzuki Swift Super 1600
  7. TT-02 RWD Datsun 240Z
  8. CC-01 Isuzu Mu
  9. TT-02 Audi Quattro

XV-01 Toyota Celica GT-Four

RallyReview-XV01-1.JPG.50c7a276f0c76d30d6f40ced9db36d2d.JPG

Tamiya’s holy grail of rally handling, imitated by many but equaled by none, the king of rally handling since 2012.

My build started with a Lancia Delta XV-01, but used a Toyota Celica GT-Four body.

RallyReview-XV01-2.JPG.8e0f0781a4fec0a5ce70aa8b1f8ec64d.JPG

  • Chassis: XV-01 (4WD)
  • Motor: Torque-Tuned
  • FDR: 8.04 (22T pinion + 68T spur)
  • Tires: Bald Rally Blocks
  • Shocks: Kit CVA
  • ESC: Hobbywing Quicrun 1060
  • Servo: JX 4409MG
  • Hop-Ups: Front double-cardans, stabilizer front & rear, full aluminum suspension mounts, aluminum pulley front, aluminum steering assembly, reinforced K & KK parts, high-torque servo saver, motor heatsink + fan.
  • Settings: #900 oil on front & rear diffs, soft stabilizers front & rear, shocks #900 oil with 1-hole pistons.

This car is the baseline for reviewing and comparing all the other rally cars. Running this car is power-sliding heaven. It is extremely easy to initiate a power-slide (drift), maintain it, and end it when you want. There is control throughout the power-slide. This ability to fully control the slide from start to finish is what, in my humble opinion, makes this car so great. Add to this the very smooth drive train, great suspension, excellent component quality and debris tolerance and we have a winner.

With the motor mounted all the way forward, there is a very clear weight bias towards the front.  I believe this serves three purposes:

  1. Reduces rear grip. Essential to initiate the slide.
  2. Increases front grip. Gives the bite needed to help initiating the slide. It also allows the front wheels to retain control through the slide.
  3. Moves the center of inertia closer to the front. This is what allows the car to shine. It is very evident, as the car slides, that the center of rotation is slightly behind the front wheels. The tail has less inertia and therefore can easily initiate or end a slide based on controller input. Higher inertia at the front also reduces the possibility of spinouts (lose control and end up with the tail facing the front) since the steering is located where the most mass is.

There is one fourth point that wraps the package: 4WD. FWD cars have all the above 3 points, but since they lack rear traction, behave very differently on a power slide (more on this when reviewing the FWD cars). With 4WD, having both front and rear traction gives the car the ability to control the slide not only with steering inputs, but very importantly also with the throttle and brake. Summarizing, the XV-01 can:

  • Initiate a slide with:
    • “Scandinavian Flick” or “Pendulum Turn”, which is done with a sudden lateral momentum transfer: steer opposite to the turn, then into the turn.
    • Braking
  • Control the car mid-slide:
    • Modulating throttle
    • Steering
  • End the slide on-command with:
    • Modulating throttle
    • Steering
    • Braking

Couple the above to the great suspension and the result is a car that goes where you want and how you want it, straight or sideways! Pure joy to drive.

Speaking of the suspension, the XV-01 has more suspension travel than any of the other rally cars on this review. This is quite relevant as it can really absorb terrain imperfections very smoothly, which in turn ensures all four wheels are in contact with the ground and no control is lost.

How will the other cars fare against such a great chassis? Let’s now cover FWD cars.

M-05Ra Suzuki Swift Super 1600

RallyReview-M05_1.JPG.b74cd7d56c6eca40912c337a9c6261d6.JPG

For more details on this build, check the earlier posts: M-05Ra Suzuki Swift Super 1600

RallyReview-M05_2.JPG.4af677094e3d61cc9562ce71154edd4b.JPG

  • Chassis: M-05Ra (FWD)
  • Motor: Silvercan
  • FDR: 6.44 (18T pinion)
  • Tires: Almost bald 60D Rally Blocks
  • Shocks: Super-Mini CVA
  • ESC: Tamiya TEU-104BK + UBEC
  • Servo: JX DC6015
  • Hop-Ups: Ball bearings, front double-cardans, aluminum steering posts, turnbuckles, 0.5mm hex spacers, high-torque servo saver, aluminum motor plate + rods, motor heatsink.
  • Settings: Shocks #400 oil with 1-hole pistons, loose front diff.

Similar to the XV-01, this car is quite front heavy, enabling comparable effects:

  1. Reduced rear grip.
  2. Increased front grip.
  3. The center of inertia is closer to the front.

There is one massive difference though: the car is FWD and this also means only front brakes. The result is:

  • You cannot initiate a slide tapping the brakes (no rear braking), limiting substantially the ability to initiate a slide. The only reliable way to slide requires a Scandinavian Flick, but this requires planning and space. Forget about initiating a slide in a pinch. On the flip side, pulling Scandinavian Flicks is much easier than with a centrally balanced 4WD car (e.g., TT-02), quite satisfying to pull off, and is probably why Tamiya decided to do a “Ra” car on the FWD M-05 chassis and not on the RWD M-06.
  • It is very difficult to control mid-slide. Utilizing the throttle almost invariably results in ending the slide. If you press the throttle and steer opposite-lock you can end by pushing forward. On the other hand, if you press the throttle & steer towards the slide, the front will lose traction ending the slide in an awkward manner that sees the nose of the car sliding out before going straight again. If you tap the brakes mid slide, the whole car basically stops without much further directional change. Note that all this also means it is virtually impossible to spinout, since the car will after a slide naturally point forward pretty much no matter what you do as long as you punch the throttle. Feathering the throttle can give a slight level of control, but it is extremely difficult to pull-off. Pretty much, once a slide starts you are at the mercy of how you started the slide. You can decide to end it or let it run its course. It's that or maybe I am a terrible driver :).

All things considered; how does this compare to the XV-01? Well, if you approach a path methodically, the M-05Ra can perform similar moves as the XV-01, but this will require practice and a great level of concentration & consistency. Any tiny error most of the time produces a botchy slide. The XV-01 does not have this problem because you can correct your slide anytime. The fact that the M-05Ra cannot initiate a slide using the brakes makes quick emergency flicks impossible.

One thing that the M-05Ra has going for it is the extremely short front overhang. The chassis can attack slopes handily without fear of bumping or scratching the front end. The XV-01 is more exposed, just look at how badly scratched the front skirt of the XV-01 Celica is! :o

Hmm...no rear brakes, how about a FWD with rear brakes? Enter the modded TT-01E FWD.

TT-01E FWD Datsun 240Z

RallyReview-TT01FWD_1.JPG.a9cc24ef362f734b477661f766ea6fe9.JPG

This car is the first kit I ever built. It has seen it all type of abuse, crashes and breakages. Most of the suspension has been replaced over the years. It still runs great though, which is a testament of how enjoyable a simple chassis with readily available spare parts can be. After getting the XV-01, it was converted to FWD and very recently a one-way was added in the rear to enable rear braking. FDR is intentionally a bit long to prevent excessive front wheel spinning on take-off (also set some throttle exponential on the transmitter).

RallyReview-TT01FWD_2.JPG.80ca65e7c6485c00be39216665091046.JPG

  • Chassis: TT-01E (modded to FWD)
  • Motor: Silvercan
  • FDR: 7.21 (22T pinion, 61T spur)
  • Tires: Semi-slicks
  • Shocks: Mini CVA
  • ESC: Tamiya TEU-105BK + fan.
  • Servo: JX DC6015
  • Hop-Ups: Ball bearings, aluminum front uprights, turnbuckles, aluminum prop shaft, rear toe uprights, front universals, rear one-way unit, high-torque servo saver, motor heatsink.
  • Settings: Shocks #900 oil with 1-hole pistons, loose front diff.
  • Mods: FWD, raised suspension, added front weight (about 150g), front braces, stiffer springs rear.

This car is great as it is an intermediate point between true FWD and 4WD. It’s a FWD on-power and a 4WD off-power. In general, it behaves very similar to the M-05Ra, except for:

  • The longer wheelbase and lesser forward weight balance makes the effects of front bias less severe. The pivot point during slides is only just a little bit ahead of the center point. When the car slides it feels more TT-01E and less M-05. All the awkwardness of FWD slide recovery is still there though.
  • Rear brakes help tremendously adding the ability to initiate slides on a whim. This is great since the added versatility helps tremendously with negotiating corners, but perhaps at the same time removes the “charm” of a FWD car.

Bottom line, it makes an interesting drive. Will fling a tail nicer than a stock TT-01E (or TT-02) but the mid-slide and end-slide control is still not there.

I’ve progressively covered a FWD car (M-05Ra) then an FWD/4WD hybrid (TT-01E FWD with rear brakes). Let’s go one step further and talk about a 4WD car with front bias. Coming up next: the TT-02XV on the next episode!

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That’s a great collection of rally cars @OoALEJOoO 👍🏻

Quick question, does the Escort body fit on the XV01?
 

(Just for a future project I’ve been thinking of)

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23 minutes ago, Re-Bugged said:

Quick question, does the Escort body fit on the XV01?
(Just for a future project I’ve been thinking of)

Since his Escort in on a TT02 chassis, I'd say yes it most likey would.   I have the Audi Quatro on a TT02 and the Delta on the XV01 and the bodies are easily interchangeable between the two chassis.  

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1 hour ago, Re-Bugged said:

Quick question, does the Escort body fit on the XV01?

Just checked and yes, the Escort body does fit the XV-01. You'll just need to trim the foam bumper a few mm.

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TT-02XV Ford Escort

Built to approximate XV handling, this TT-02XV can be considered a “poor man’s XV-01”. The idea behind this build is to keep it low budget with minor modifications to achieve that XV feel.

RallyReview-TT02XV_1.JPG.61038acc37accc35668e575c8d67012c.JPG

For more details on this build, check the earlier post: TT-02XV Ford Escort

RallyReview-TT02XV_2.JPG.72942e0aa210622962dae20f9c450054.JPG

  • Chassis: TT-02
  • Motor: Torque-Tuned
  • FDR: 7.28 (25T pinion, 70T spur)
  • Tires: Slicks
  • Shocks: Mini CVA
  • ESC: Tamiya TBLE-02S + fan.
  • Servo: JX 4409MG
  • Hop-Ups: Ball bearings, turnbuckles, TT-02 motor heatsink, high-torque servo saver.
  • Settings: Shocks front #900 oil with 2-hole pistons & rear #400 oil with 3-hole pistons, loose front diff, putty-locked rear diff, high ground clearance, stiffer springs rear.
  • Mods: Added front weight (about 160g), front braces.

This car ticks all the boxes as the XV-01:

  • Decreased rear grip
  • Increased front grip
  • Forward center of inertia
  • 4WD

Control-wise, it also has the full repertoire of handling capabilities as the XV-01 to initiate slides, control the car mid-slide and to end slides. All looks great so far, in paper at least.

So how does it handle? In short: a significant improvement over a TT-02 and definitely close to a XV-01. The TT-02XV is a blast to drive! :wub: It definitely has similar traits to the XV-01. The car behaves closer to a XV-01 than to a stock TT-02. Quite a treat to race it along twisty roads! :)

All is good, but there are still some things that keep it from reaching that heavenly XV-01 handling.

  • First, the TT-02XV is heavier than the XV-01 given weight was added. The car originally had a Silvercan motor but it was clear the added weight was too much for it. Power was upgraded to a Torque-Tuned and it is now much better. To be fair, my XV-01 also has a Torque-Tuned.
  • Second, even with the added weight it is clear while driving it that the center of inertia has moved forward but is still not as forward as the XV-01. This can probably be improved with additional front weight, but likely this might now need a beefier motor than the Torque-Tuned to keep-up.
  • Finally, the smoothness of the suspension & drivetrain of the XV-01 is on a different league. The TT-02XV is not bad, but you can tell it is a budget car. This is both a pro and a con. The fact that it is a cheaper/budget car means you can drive it without fear.

I think the TT-02XV is a success. Plus, it seems entire possible to make if even better by further tweaking. A shorty Lipo battery placed forward, instead of the NiMH I use, would definitely be an improvement.

So…does it replace a “stock” TT-02 in rally trim? Let’s find out with the next car.

TT-02 Audi Quattro

Fairly bare-bones, this car can be considered a basic TT-02 rally setup featuring only essential hop-ups.

RallyReview-TT02_1.JPG.c8ed4676d83e3e08b023d989dcebca14.JPG

What perhaps makes this build a bit distinct are the addition of some custom front mud-guards to keep debris out. They really help.

RallyReview-TT02_2.JPG.7a22e73fc120fe5fdd409b35d9a405cd.JPG

  • Chassis: TT-02
  • Motor: Silvercan
  • FDR: 7.28 (25T pinion, 70T spur)
  • Tires: Semi-slicks
  • Shocks: Mini CVA
  • ESC: Hobbywing Quicrun 1060 + fan.
  • Servo: JX DC6015
  • Hop-Ups: Ball bearings, turnbuckles, low-friction suspension balls, TT-02 heatsink, high-torque servo saver.
  • Settings: Shocks #1000 oil with 3-hole pistons, loose diffs, high ground clearance.
  • Mods: Front braces, front mud-guards.

Like the TT-02XV before it, this car has all the repertoire of moves on its toolbox. This time however, the center of inertia was not altered, and located at around the middle of the car. What a difference this makes! All the cars reviewed so far had the center of inertia moved forward, and therefore the pivot point of their slides felt quite great. On this TT-02 you can clearly tell the rotation is at the center of the car, which robs away that cool rally feel. I’ll exaggerate, but to make a point, the car slides less similar to this:

maxresdefault.jpg

And more similar to this (Speedeez):

Speedeez_baseplate.jpg

Again, this is an exaggeration, but you get the idea. The car literally pivots around its center. I reckon this might actually help you do better lap-times (and save tires) at the expense of losing that rally feel.

Being lighter, the Silvercan on the TT-02 feels about as punchy (if you can call it that) as the TT-02XV with the Torque-Tuned (given its heavier). Top-speed was a bit lower as expected.

To wrap up, does it make sense to build a regular TT-02 rally car now that a TT-02XV has shown to be a simple “no-cost” option? My answer is an absolute no. In fact, I am thinking to now update this TT-02 to TT-02XV (pass the Torque-Tuned) to it. Then, to the TT-02XV, add even more weight to the front and fit a Sport-Tuned.

If I may suggest, Tamiya could easily create a TT-02Ra kit (naming would make more sense than TT-02XV) with the following features:

  • Dedicated front bumper with integrated weight holder
  • Sealed ball bearings
  • CVA shocks, harder springs rear
  • 22023 chassis cover
  • Torque Tuned motor (which is already bundled in many kits)
  • Rally body

You can see that I’ve chosen to review the cars in a progressive order of weight bias from front to back. We have covered front and center weight bias so far. On the next chapters I’ll cover the cars that progressively have a rear bias. Until the next one!

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On 4/23/2023 at 8:03 PM, simalarion said:

Samantha Fox late 80’ model, since i was around 13 i was constantly dreaming off that Body.

I'm not sure you're her type :P

 

On 4/23/2023 at 12:36 AM, OoALEJOoO said:

 

FordEscort_17.JPG.73ce3b94b545cd6aba03815212d9f33a.JPG

 

 

Blooming heck (or much stronger words to that effect); that's just a perfect beauty! Great Michelin man too!

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On 4/30/2023 at 3:24 PM, OoALEJOoO said:

Chassis: TT-01E (modded to FWD)

I love that you found a use for Tamiya Box Wrenches :lol:

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On 4/22/2023 at 10:59 PM, Kpowell911 said:

Im of that opinion too, the panel lines make it look like a render or a prototype. Maybe if they were thinner? I dont know. 
 

 However, @OoALEJOoO I appreciate your reply and Im extremely envious of your abilities. That looks absolutely amazing!

Marmite ❤️❤️❤️❤️

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Plot twist...

TT-02XV Mk2: Mitsubishi Lancer Evo VII WRC

mitsubishi-lancer-evolution-vii-wrc-2001

Instead of upgrading the Quattro to TT-02XV spec and then adding power to the Escort to TT-02XV, I've decided to leave them as-is, and build a new car from the kit parts not used on the previous project. The idea is to further upgrade the earlier TT-02XV spec with even more front weight and a more powerful motor.

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TT-02XV Mk2: Mitsubishi Lancer Evo VII WRC BMW M3

Too much stuff going on right now and the Mitsubishi body is now put on the backlog. Instead, a beat-up BMW M3 will be used temporarily. Held together by tape and missing some pieces, it somewhat fits the rally theme!!

Evo7-02.JPG.18a882f3d0bb4527171216f9aa8a0822.JPG

Moving to the good news, the TT-02XV Mk2 chassis got built and tested :).

Evo7-01.JPG.4639b94e82b747df0f61f755cdcd1d15.JPG

I ended up deciding to save the Sport-Tuned motor for another build and use a Torque-Tuned but with a smaller pinion to get more punch (albeit lower top speed). Overall, it's virtually the same spec as the earlier TT-02XV Mk1, but with a shorter FDR and ~70g more added front weight.

  • Chassis: TT-02
  • Motor: Torque-Tuned
  • FDR: 7.91 (23T pinion, 70T spur)
  • Tires: Slicks
  • Shocks: Super Mini CVA
  • ESC: Tamiya TBLE-02S + fan.
  • Servo: JX 4409MG
  • Hop-Ups: Ball bearings, turnbuckles, TT-02 motor heatsink + fan, high-torque servo saver.
  • Settings: Shocks front #900 oil with 2-hole pistons & rear #400 oil with 3-hole pistons, loose front diff, putty-locked rear diff, high ground clearance, stiffer springs rear.
  • Mods: Added front weight (about 230g), front braces.

Testing the Mk2 car side-by-side with the Mk1 was a treat. The shorter FDR (7.91 vs 7.28) created slightly more punch and sliding ability, even though the car was a bit heavier. Top-end maximum speed was a bit slower as expected. Now to the rally feel: all the traits of the Mk1 were still present but just slightly improved. It's clear that adding more front weight is a step in the right direction, and perhaps the sweet spot is not yet reached. More weight would offer some improvements, but this would now require a Sport-Tuned motor and perhaps the higher total weight will start to make the car sluggish. Hard to tell until a new Mk3 comes along! At some point perhaps the Mk1 will be upgraded to a hypothetic Mk3 (~350g + Sport-Tuned).

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20 hours ago, Re-Bugged said:

Do you think there will there ever be an XV02 added to the mix??

There definitely will :). Chassis is on-hand, the body is already painted, and the cockpit is next. The trick is always finding free time!

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MF-01X VW Hornet Beetle

If Ruffshod Rod traded his Hornet for a beetle, this would be the result!

Details on this build can be found here: MF-01X Hornet Beetle Rally build

VW-1.JPG

  • Chassis: MF-01X
  • Motor: Silvercan
  • FDR: 7.54 (20T pinion)
  • Tires: 60D Radials M
  • Shocks: Super-Mini CVA
  • ESC: Tamiya TBLE-02S
  • Servo: JX 5508MG
  • Hop-Ups: Gyro, ball bearings, heatsink, high-torque servo saver.
  • Settings: Shocks #400 oil with 2-hole pistons, loose diffs.
  • Mods: None.

We now **** to reviewing cars with a rear-weight balance, with the first one being perhaps the least rear-balanced since it is 4WD. The MF-01X chassis is an odd 4WD thanks to its motor being mounted at the rear, which detracts some of the usual traits found on the other more balanced 4WD (such as the TT-02 Audi) and has a combination of traits found on RWD cars. Something that it is also a bit unique to this chassis is that the front shocks are mounted on a steep angle, while the rear shocks are vertical. For the same spring stiffness, the rear is far softer, resulting in significant weight transfer to the rear (and stability when accelerating) but somewhat lousy braking as there is little weight transfer to the front. Summarizing how it behaves while rallying:

  • Initiate a slide with:
    • Scandinavian Flicks: Doable, although they tend to be a bit more aggressive or "violent" than the other 4WD. The added mass on the rear makes the pendulum hard to stop once it starts. You need to be careful not to overdo your pendulum or it will result in an awkward move that's a bit hard to predict where and when it will end.
    • Braking: The car has powerful rear braking given little weight transfer goes to the front (angled springs at the front). A little tap in the brakes is usually enough to create a slide. The issue is that the slide is usually a bit sudden and hard to predict. This is why I installed a gyro on this car, to make it a bit more controllable on loose terrain.
  • Control the car mid-slide:
    • Modulating throttle: this is a bit more difficult than with more balanced 4WD but doable. The car pivots in quite an odd manner. If the XV-01 pivots gracefully with a center behind the right axle, the MF-01X pivots a bit strangely with a center in front of the rear axle.
    • Steering: Also doable but not as responsive as a neutral 4WD.
  • End the slide on-command with:
    • Modulating throttle: Possible but requires more gentle throttle changes to prevent the rear from going pendulum on you.
    • Steering: Going opposite lock can end a slide but it requires far more skill than an XV-01. Given we only have split-second visual feedback when running RC cars, I would argue that controlling it is quite difficult. Again, the gyro helps here.
    • Braking: Usually results in flicking the tail, which might not be the desired result.

Something else that affects the M-sized cars while rallying is the diameter of their wheels. Being smaller, bumps are more noticeable and can upset the car easier. Also, the cars are lighter, which can also make them easier to upset on uneven terrain. These two combined create a car that tolerates rough terrain less than a 1/10 touring-sized rally car. A solution could be to soften the suspension, allowing better compliance with terrain on smaller tires.

To wrap up, the MF-01X is a fun car because it's different, and this is what having different chassis is all about. It doesn't crate the same satisfying rallying experience as the XV-01 or the other cars (TT-02XV Mk2 coming close). Still, it's a nice car to drive and no better chassis to fit a VW body on!

I recently bought a cheap digital scale on ebay and got a chance to measure the weight on each of the cars wheels. With this, it is possible to calculate the CG on the horizontal plane. On the graph below, the cars are ordered according to the position of their CG, from front-most to further back. The MF-01X is so rear-balanced that only the M-06 beats it (although by a large margin).

CG.thumb.png.22c0527f4083cfc07948a21863ff87f3.png

 

 

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TT-02 RWD Datsun 240Z

Another sample of a rear-balanced rally car, this time in RWD configuration. Tamiya's TT-02 4WD chassis was converted to a RWD by removing the central propeller shaft. Additionally, the front drive train was kept, with the front differential putty-locked to control oversteer.

More info on this build can be found here: TT-02 RWD Datsun build

Datsun-RWD.JPG

  • Chassis: TT-02
  • Motor: Silvercan
  • FDR: 8.27 (22T pinion + 70T spur)
  • Tires: TT-01E Racing Truck (51589) with M-size rims and DN-01 sponges (51448).
  • Shocks: Mini CVA
  • ESC: Tamiya TBLE-04S + fan
  • Servo: JX 5508MG
  • Hop-Ups: Gyro, ball bearings, TT-02 heatsink, high-torque servo saver, TT-02 cover, aluminium front shock tower, turnbuckles.
  • Settings: Shocks #400 oil with 2-hole pistons, loose diff rear, putty-locked diff front, high ground clearance.
  • Mods: Front braces.

The best way to describe this car is a regular 4WD TT-02 but with a more tail-happy behavior. The locked front diff really counters on-power and off-power oversteer, making it quite controllable compared to a regular RWD without a front diff. Braking, however, is a different story since only having rear brakes requires very careful feathering of the brakes on corner entry. On the flip side, straight-line acceleration is a fantastic and very stable. Having high-ground clearance, coupled with the slightly larger TT truck tires (70mm OD, vs 65mm OD of regular touring tires, although Rally Blocks when new are also 70mm) and soft springs, creates a very cool rear weight transfer on acceleration.

This car really shines as a rally car on concrete or any other medium-to-high grip surface. The tall-wall TT truck tires have significant lateral compliance which also results in lateral weight transfer. All this weight transfer translates into a car that is simply a joy to watch as you see tires & suspension literally fighting with the high-grip running surface. With good grip, having only rear power is not a problem and the car feels really planted.

On looser terrain, having RWD power makes controlling and exiting slides somewhat challenging. It is easy to create a slide, just not that controllable once it starts. On high-grip surfaces this is not a problem, but on loose gravel it can be a handful, which is actually what makes this car quite unique, challenging and ultimately fun. The gyro helps here in making the car more forgiving and consistent. There is also the added feel of scale, since the real-life Datsun 240Z is a rear-wheel drive sportcar.

Running with the chassis cover does heat the motor a little bit on hot weather, even though it's a humble silvercan running with a fairly short 8.27 FDR. I'm thinking to add a small on top of the heatsink.

Both the TT-01 and TT-02 chassis really shine with their versatility. FWD, 4WD and RWD modified rally cars are all unique and great to drive :wub:.

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M-06Ra Mazda Miata

The final sample of a RWD rear-balanced rally car. Converting the stock M-06 to "Ra" spec involved using high-ground clearance uprights and some other minor bits.

More details about this build: M-06Ra build

Miata.JPG

  • Chassis: M-06
  • Motor: Silvercan
  • FDR: 5.79 (20T pinion)
  • Tires: 60D Radial Front (50683), 60D Radial M-Grip Rear (50684)
  • Shocks: CVA Mini with kit springs, 400 oil
  • ESC: Tamiya TEU-105BK
  • Servo: JX 5508MG + Gyro
  • Hop-Ups: Gyro, full ball bearings, rear 90deg universals, 0.5mm wheel spacers (rear), full turnbuckles, HT servo saver, motor plate + DF-03 finned-rod + fan.
  • Mods: Rally conversion with increased ground clearance (M-05Ra uprights), dirt guards.
  • Settings: 225mm wheelbase, loose rear diff.

Let's compare it with the TT-02 RWD Datsun. The M-06Ra is at a disadvantage in that it does not have a putty-locked front diff and is considerably more rear-heavy. It's advantage, however, is having higher-grip tires on the rear (M-Grip) while the Datsun has the same tires front/rear. Once the rubber hits the road, on all surfaces the M-06Ra is more nimble and just as stable as the TT-02 RWD, while sharing all the RWD traits described earlier. Enabling the gyro benefits both cars just as much, taming the tail when running on loose surfaces. To keep the motor cool, the car has the Yeah-Racing motor plate (which also includes a radiator) and also one finned-rod heatsink from the DF-03 set, attached the plate and just above the motor. A fan (with a TT-02 scoop) is mounted just on top of this finned-rod.

The M-06Ra is a treat to run. It makes a more satisfying rally car than the FWD M-05Ra. It also has a very small overhang both front and rear which helps clearing slopes and obstacles. Those custom dirt guards help tremendously in keeping the tub clean(er). Another plus of the M-06 is how smooth & silent it's drivetrain is, similar to the XV-01, and definitely much quieter than the TT-01/2.

What really has me impressed, and actually quite puzzled, is that I also have a regular non-rally M-06 and the "Ra" version handles far FAR better on all surfaces!! I've been trying to setup the regular M-06 without much success. The issue is that there is severe mid-corner oversteer, both on power and off. The M-06Ra does not suffer from this. Could it be that the added ground clearance and suspension travel creates better weight transfer and therefore overall grip? The chassis layout does look like a buggy after all. I'm quite bummed with the regular M-06 because right now it's markedly inferior. I've setup the regular M-06 as close as possible to the M-06Ra and still have the issue (only differences being the stock ride height and 249mm wheelbase). Maybe converting the regular M-06 to "Ra" high-ground clearance is the solution?

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