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Four wheel drive

16K views 36 replies 21 participants last post by  42redcat  
#1 ·
There two methods. One is to use a drive belt and pulley. The other is an extended motor shaft with pinion and contrate gear wheel.
Which system is the most effective, in the creation of four-wheel drive in Slot cars?
Some of the factors to consider will be
1. Electrical current draw.
2. Weight.
3. Motor power output/rpm.
4. Spring couplings.
5. Position of motor and balance of the car.
6. In a sidewinder drive, is the motor heavier left or right?
7. Tyres and track type.
I have read Hub Habets excellent article, about exchanging drive belts for new O-rings.
My slot car garage; does not have any four wheel driven. So before I purchase, what are your opinions and experiences?
 
#2 · (Edited by Moderator)
In my experience of quicker cars the answer is clear
Rear wheel drive goes better.

I remember some guy turned up with a 4WD car that went OK, not as good as the better rear wheel drive cars but OK.
Then the 4WD fell off and when put back on it went better, still not as good as the better rear wheel drive cars but better than before.
When he checked out why it had improved he found the drive to the front wheels had become disconnected.

If you really want 4 WD there is another option - twin motors.
 
#3 ·
Hi!

We run rally cars as one class. Last year we decided to allow higher RPM motors for 4WD rally cars. Rules dictate that you have to have mechanical 4WD construction, in other words pinion and gear at the front. We thought that 4WD cars would not have any chance competing with rear wheel drive cars. Boy were we wrong. Nearly all drivers switched to 4WD cars and SCX Sport version of Citroen Xsara is dominant. We run without magnet.

1st competition:

Image


2nd competition:

Image


Our Rally classification for motors:

Allowed 2WD motors are:
RX4/RX41/RX42, RX8/RX81, Ninco NC 1, Scalextric (Hornby Hobbies) Mabuchi 'S', Auto Art Mabuchi 4WD ja 2WD ja Carrera Mabuchi sekä Cartrix TX-1, Scaleauto SC08, Cartrix FX-Sport

Allowed 4WD motors are:
Cartrix TX4
NINCO NC7
SCX Pro Turbo 4x4
SCX Pro Speed Double Rally 4x4

Those 4WD rally cars go sometimes faster than our cars at the Touring class (MB CLK´s, Renault Meganes, Alfa 156, BMW320i... etc)

Very carefully built 4WD car will be very competitive with the right motor. Some of the drivers here are planning on building 4WD cars even for our fastest GT-classification (motor free, nomag, GT cars).

Cheers!

Julius
 
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#4 ·
To know the purpose of these questions would be helpful in answering them.

As to the checklist of issues:
#1 & #2 the answer is negligible.
#3, just like any other motor use, more rpms = more speed, more torque = more power
#4 bad idea in any slot car. I don't know of any 4WD's w/ one.
#5 inline boxer motors give good torque & COG
#6 ??? I've only seen Scaley put this in a 4WD & as their rally cars are no good for rally, I regard this as a non-issue.
#7 individual choice. We run rally on Ninco, Ninco rally, & Classic/SCX. Sport is ok for occasional use as a paved road option. We run no-mag & rubber tires; Ninco 19x10's fit several other wheels & have good grip. Silicones & Urethanes provide too much grip for realistic looking rally driving.

I prefer belt drive 4WD; any lag to the front wheels seems to be a benefit allowing for a slight difference in rpm's similar to a real differential set-up. Ninco Pro versions have dual belts for more positive power transmission. Slot.it & Ninco sell pulleys & belts for conversions or adding a second belt drive. Shaft driven cars are noisier (esp. SCX) & have the possibility of the front shaft popping out of gear if there is too much resistance. I do however like the Cartrix Hyundai, it is quick & smooth.
My Ninco ProRace Mitsubishi Lancer is a car w/ brute force - Spirit Peugeot's are also 4WD monsters that are hard to beat.
 
#7 · (Edited by Moderator)
First, I would like to comment on Julius results. Which are not surprising. But the reason why the 4WD cars
did better was because the motor used, the SCX ProDoubleRally, has a high magnetic pull (11 UMS), higher than the other motors on the roster.
Also adding to that, the distance of the motor to the rails in the SCX Pro Xsara is set to be minimal adding to the magnetic pull.

Now this higher magnetic pull is essential. A car with a motor with 8 UMS or less (NC5 6UMS, NSR King 8 UMS, Cartrix TX6 7.5 UMS,
MB Gnik 7.5 UMS) will never have a chance against a car with a motor with 11 UMS (with equivalent cars and drivers). So much that
in Spain there are two categories in rally: N (motors with 7.5 UMS or less) and SuperN (motors with less than 11 UMS). I get exactly
the same results on my track my fastest cars all have motors with 11 UMS (green Avant slot, Spirit 3X or xXx, Mb SongNa, never got
as good results with open can boxer but not clear why).

Remember that running without magnets does not mean that you are running magnetless.

I think that 2WD is a bit better on non dirty tracks, on not dirty tracks pulley 4WD is better than "mechanical" 4WD and on dirty tracks
"mechanical" 4WD is better than 2WD and pulley 4WD. But some times the differences are not that big and is a question of taste.
If you have pulleys it is important not to have too much tension on the belts (which will slow down the car and make it a bit more
jumpy). If you go too far decreasing the tension the belts might come off sometimes which if happens in a competition is deadly.
 
#8 ·
I have various 4x4 cars,
the 2wd with added belts are the fastest {Spirit 205 NINCO prorace}
they do have more powerful motors though {Spirit xXx NC6}

Direct drive 4x4 as on SCX may be a bit slower but as much fun
Image


Belt drive can slip were as direct drive wont,
Its recommended that you put higher gearing on the front to get better traction out of the corners

Either are good it depends on how you want to drive them

John
 
#9 ·
Hey Guys, as I have said before, set the front wheels just skimming the track, and with slightly bigger front wheels, as the car tilts into the curve, the outside front touches and revolving faster pulls the car into and round the curve !!.

Non magnet on wooden tracks !!.

VBR Chris A.
 
#10 ·
The dual motor 307 handles better than its standard version, obviously its heavier, which helps, but the power delivery is about the same as it was when it was single engined.

Image


Its not slower and feels more sure footed.
Just remember, it will need its own power supply on its lane as standard supplies are designed to power 2 cars!
 
#11 ·
One of the members of my club (Shoreline Model Raceways) entered a 4WD car in the 2006 Race Across America. The car used a Slot.it HRS sidewinder chassis and was powered with the Slot.it black can motor. A belt and pulley system was used and the car had an Audi body because the rules required that for 4WD cars the 1:1 car had to be 4WD. The car used Supertires silicone tires on Kai's aluminum wheels. The class was for non-magnet cars. Since it was a proxy series the car was run on a variety of tracks, plastic, painted plastic and wood and was driven by many different people. The car was often the fastest qualifier and won a number of races. I believe that some racers had trouble with the car because it did not behave like a rear wheel drive car and did not like to slide around. When a well tuned rear wheel car is driven at the limit the back will slide out in a predictable fasion. The 4WD car could go faster, but it would deslot before it would slide out.
 
#12 · (Edited by Moderator)
It is very easy to check in a relevant way the differences between 2WD and 4WD. Set the car with pulleys and try the car with belt and without the belt. Set the car with "mechanic" 4WD and try it with front crown and without it. I have done it and never got better results with 4WD. On the other hand, I have to say that I am used to 2WD driving and never went to extensive fine tunning of the 4WD version, just did what I said above and played with the tension of the belt. Also, from reading Spanish forums I never read that 4WD is better unless you are running on dirty tracks.
 
#13 ·
Hi Everybody,

In the current NSCC-Journal (June 2008) is an article about relocating the engine in Scalextric WRC cars.
I chose for the option to use only the parts of the car itself.
So, no second engine or rear axle of a Mitsubishi WRC.
With my solution, you only have to buy a 2mm spacer, expoxy glue, 2 pieces of wire and some patient, to improve your stage times by 15%.
(With an o-ring 59x1,5mm fitted:+3%= 18% faster).
It is cheap and a lot of fun.

rallyhub

Image

On the outside, there is no difference, but now the Scalextric WRC cars are a lot faster and safer to drive.
 
#16 ·
Shaft drive 4WD is direct, belt drive 4WD feels like it 'gives' as it allows slight front/rear drive changes due to the belt. Shaft drive (SCX twin shaft motors) are only available up to a certain performance whereas belt drive setups allow a vast choice of motors.

I like both types but prefer the feel of direct 4WD in Slot Rally.
 
#18 ·
The quickest SCX double shaft motor is the Pro Double Rally but it's nowhere near as quick as the standard 18K yellow sticker motor found in the 4WD MSC RS200 or Metro 6R4.
 
#25 ·
Hi Andi,

Very impressive mechanics you have in that model!! 1:32 model?
Are those diff's commercially available? I can't google them up. Did you modify them?
Isn't this too complex? More parts that can fail in racing? And maybe more time to repair?
Until now I like slot.it's 4WD system.

Gerrit
The diffs are all Kyosho RC parts. They have mini-Z and D-nano ranges which go down to 1/28 which is getting close enough to 1/32 to make it viable.
One needs to do a fair bit of engineering to get them to work with slot cars as they are designed for use with independent suspension which of course we don't need.
I have recently redesinged the whole back end and remade the chassis after backing this into the wall in practice at Prest Park. Soon to be run at Rockingham I hope.....
Cheers
Andi
 
#26 ·
For the rest of us mortals (!) the Slot.It belt driven 4WD is a good compromise. It's available on the Audi R18 and there are also compatible chassis for the Scalextric short wheelbase Quattro and the Delta S4 available through the Slot.It Shapeways shop. You can get bands of the correct length to fit these chassis from Pendles and elsewhere. All up it adds about ÂŁ70 to the total cost of Scalextric's effort.

I always preferred the SCX shaft drive (also on AutoArt) to the rubber bands used by Ninco and Team Slot. I see that the new 'Pro' chassis on the Team Slot Quattro is 2WD only. Much better for a slot car IMO.