Vintage Le Mans modified build

[GearHead36]

The local club just announced a modified vintage Le Mans mini-endurance race (12 minute heats) in October. Help me build something competitive. The rules are:

- Car - Le Mans 1967 - 1971 era. Doesn't have to be a livery that actually competed at Le Mans. For example, the Scaley Ferrari 412P Targa Florio 1967 would qualify. The 412P competed at Le Mans, but not the actual car with the livery of this Scaley.
- Motor - 26K max.
- Any gearing.
- Must have interior, may be lightweight.
- Traction magnets not limited. No downforce limit.
- Rubber or urethane tires.
- Must have working headlights.

The only cars I have of the correct era is a Fly 917K and a Scalextric GT-40 (any 917 and any GT-40 is legal). Would either of these be good candidates? Would something with a motor pod be better? With no limit on traction magnets, does a motor pod really have any advantage? Would I be better off with a no-motor-pod car with lots of magnets, and better running gear? I don't have much experience with the above cars in actual racing. And no experience with races with heats longer than 3 minutes.

I need something durable, as the impacts will undoubtedly be severe and unavoidable. Earlier this year, we had a similar event, a modified Trans-Am race (w/26K motors), and I'm surprised that my car came out of it with no major damage.

I'm kinda leaning toward a Scaley GT-40. Scaleys tend to be durable (my modified T/A is a Scaley, and it survived several hard impacts), and most of them already have headlights. I would just need to upgrade the motor, running gear, interior, and add magnets.

[docdoom]

I my self would be trying a slot it or nsr gt 40 or nsr 917 and install a light kit. And tune the car from there. Be miles ahead from the start over a fly or scaley car and be cheaper and better performance.

[HO RacePro]

I'll second the recommendation for a SlotIt car. Much more competitive than Scalectrix or Fly out-of-the-box. Urethane tires would probably work best.

A motor pod setup with slightly loose mounting screws works well. If you want to reinforce the chassis, piano wire is a good choice. But don't add a lot of weight and keep any added weight low. Be judicious.

You want your tires bonded to the wheels and ROUND! Also, gear mesh is critical. I'm not going to go into how to achieve those desirable factors. Good information on that exists elsewhere. But really, you want to spend a lot of time making sure everything associated with the rear axle is set up optimally. A great rear axle setup won't necessarily win the race, but a poor setup will certainly lose it!

Ed Bianchi

[chrisguyw]

If you are running a considerable amount of downforce (magnets) a motor pod (loose or otherwise) will have little impact............and, .... do not add any weight !!!!! ....weight in a magnet car negates the effectiveness of the magnets as they must hold a heavier car on to the track........as a test , run your magnet car without the body,...it will handle/stick/lap much better.........less weight in a magnet car will produce quicker lap times

Tune by using various sized magnets in various locations, depending on the handling characteristics.

The motor you choose will largely dictate the gear ratio (what will you be using ??), and , again depending on the downforce, tire choice is less critical, ......that said without knowing more, I would lean towards Urethane, as they are much easier to true, and they are less affected by dust/debris on the track.

Cheers
Chris Walker

[chappyman66]

Slot.It Matra. Very fast. Add lights, tune as needed.

[GearHead36]

If you are running a considerable amount of downforce (magnets) a motor pod (loose or otherwise) will have little impact............and, .... do not add any weight !!!!! ....weight in a magnet car negates the effectiveness of the magnets as they must hold a heavier car on to the track........as a test , run your magnet car without the body,...it will handle/stick/lap much better.........less weight in a magnet car will produce quicker lap times

Tune by using various sized magnets in various locations, depending on the handling characteristics.

The motor you choose will largely dictate the gear ratio (what will you be using ??), and , again depending on the downforce, tire choice is less critical, ......that said without knowing more, I would lean towards Urethane, as they are much easier to true, and they are less affected by dust/debris on the track.

Cheers
Chris Walker

This is kinda what I was thinking. The more magnetic downforce you have, the less advantage a motor pod gives you. What I don't know is, can you add enough magnets to totally eliminate the advantage of a motor pod? My guess is, yes. It may not matter. Latest update from the rules committee mentioned possibly requiring a one-piece chassis. I guess I really need to wait until the rules get finalized.

Motor... I used an NSR 25K in my modified T/A (same motor I'm planning on for this car), and I went with an 11T pinion. Not sure of the spur. Whatever is stock. I had 11, 12, and 13T pinions. I started with 12T. It had great straightaway speed, but not enough punch off the corners. 11T was better.

As for urethane vs rubber... on this track... I favor rubber. The track is in a dusty environment, and no matter how clean it is at the beginning of a race day, all during the day, it collects more dust. I've done tire testing (admittedly with a no-mag Slot.it Group C). Silicones provided the highest peak grip, but that grip went away the fastest. Rubber treated with tire oil provided the lowest peak grip, but lasted at least 10 minutes. Urethane was between the two. More peak grip than rubber, but less than silicone, and that grip lasted longer than silicone, but less than rubber. I didn't get to time long heats, but I strongly suspect that for 10+ minute heats, rubber would provide the most total laps. Not sure the results of another tire test with a magnet car would be the same. Hopefully, I'll get a chance to do more testing.

[GearHead36]

I suspect the DF will be in the 400+ range. I was able get close to 400 in my modified T/A. This car will be lower, and I wouldn't be surprised if I could get 500 or more.

[chrisguyw]

At 400+ gms. of downforce,.......pod vs. no pod is completely irrelevant...........with a 26K motor you likely will be full punch around the whole track.

If you are restricted to 26K, you may want to look into the ProSlot Euro Mk 1 PS 4000 motor..........this motor has the same dimensions as all FC-130 motors, and will therefore pop into any chassis/pod where a FC-130 is used. It is rated at 26K, but, due to the fairly strong ceramic magnets (stronger than any typical FC-130) smaller air gap, and good quality motor brushes and springs, it does produce considerably more torque than any of the "plastic car" FC130 motors, which will be a benefit, when running high magnetic downforce figures.

Why not try tossing the magnets altogether ????

[GearHead36]

Great! I won't waste money on a motor pod car, as whatever I get has a good chance of collecting damage. Thanks, Chris, for the recommendation on the ProSlot Euro Mk 1 PS 4000 motor.

As for tossing the magnets... I'd LOVE to. I'm the banner carrier in this club for no-mag racing. I'm one of four regulars. There are four other semi-regulars. Two of the regulars are diehard magnet racers. The two other regulars prefer no-mag. I'm the new guy, so my opinion doesn't carry a lot of weight yet.

[GearHead36]

I just picked up my first Slot.it LMP, which has a long can motor. The motor is 21K, but it has, as I recall, over 300 gcm of torque. The ProSlot Euro Mk 1 PS 4000 is around 155 gcm. Peak power for the 21K long can is higher than that of the 26K s-can. Is there any way to put a long can motor in this build? Preferably in an AW setup.

[slothead]

With this basic precondition in the rules:

- Car - Le Mans 1966 - 1974 era. Doesn't have to be a livery that actually competed at Le Mans. For example, the Scaley Ferrari 412P Targa Florio 1967 would qualify. The 412P competed at Le Mans, but not the actual car with the livery of this Scaley.

How does a Slot.it LMP qualify?

[GearHead36]

The LMP doesn't qualify. At all. Not even close. I just picked one up, and it was my first experience with a long can motor. I didn't realize that they had so much more torque than s-cans. Given that they DO have lots of torque, I was wondering if there was a way to put one in a legal car. The motor for this build must be 26K, but there is no limit on torque. I can't find a legal car that will accept a long can motor.

[slothead]

Thanks for the reply. Don't the rules say '26K max'? Maybe a lesser rpm motor that fits your ideal car will be a better choice. Traction and handling are apt to outperform pure speed.

[GearHead36]

True. 26K max. I meant to say "must be 26K max." The track is long and fast, and rewards power. The SCM's of the club have 40K motors on some of their cars (not for this class, though).

So... does anyone know if there's a way to stuff a long can motor in a 67-71 Le Mans car? Ideally, a 3D chassis for a Scaley Ferrari 412P. I couldn't find one on Shapeways. NSR makes some cars that would be legal, but they're all SW configuration. Is there an AW motor pod that fits one of these cars, and accepts long can motors?