In preparing for an upcoming race we are using that great device called the Magnet Marshall in an effort to more equalize our class of AFX SRT cars. We are racing a class open to the Chapparals, GT-40s and the Cobra Daytonas.

Out of the package we have found that the GT-40s all have close downforce in the 172 gram to 180 gram range.

The 2 Chapparals range from 147g to 178g.

And the Daytonas all have downforce in the 150s gram range with the exception of 1 car with 180 grams of downforce.

What we are attempting to do is get the field in 10% of each other as far as downforce goes. I have had experience with doing the same with 1/32 scale cars but this is the first time for HO. Does anybody have any input/experience in getting these cars more equal in magnetic downforce?

I am going to sand the tires as one effort. Any other ideas?

Jim Norton
Huntsville, AL

I would say that you're on the right track with sanding the tires. But I wouldn't use a Magnet Marshal. I'd equalize them on a skid pad.

Jim---- You need to take great care to put the cars on the MM exactly the same to get an accurrate reading. Read the same car 4 or 5 times and see if your reading changes. We have found that the speed of the SRT is more of a variable than the handling with stock tires. That will be the challenge for equalization. For handling dbl flanged rims and slip-ons give you some options. If its an IROC put the best cars in the gutters. If its a race with assigned cars, give the worst drivers the best cars.

Neorules:

We put everybody's cars in a pool and one draws for the car he will drive. This is why we are trying to get them all close magnet wise.

There are many other factors but nothing ruins it quicker to have a car with a magnet making only 75% of the downforce the other cars have.

I have thought about putting the lower downforce chassis under those low to the groung GT-40 bodys as a way to even things up. What is lost in magnet is gained by a lower center of gravity.

Thanks,

Jim Norton
Huntsville, AL

Jim-You're right. I can really feel the difference with the GT40. It really holds the track well. The Chappy and the Daytona are pretty good too. The Indy cars, with their low center of gravity of course are the best stickers. BTW, all of my Indy's, GTP's and Lemans style cars boast SG+ chassis. All of my stockers are SRT. I just like it that way.

Is there a magnet marshal built for HO cars?
The 1/32 one would have to be modified to
correctly read an HO car.

The Magnet Marshall works great for HO. The only possible thing that might give the Magnet Marshall trouble with HO is very, very low riding cars.

Everything works great until the magnets bottom out and you will get very false readings. These are easy to discern when they happen as they are off as much as 50%.

We use the device for both HO and 1/32 and I will have to say its one of the neatest pieces of equipment to analyze slot cars with. For all those who don't have one they are worth the high price they cost!

Jim Norton
Huntsville, AL

The Magnet Marshall works great for HO. The only possible thing that might give the Magnet Marshall trouble with HO is very, very low riding cars.

Everything works great until the magnets bottom out and you will get very false readings. These are easy to discern when they happen as they are off as much as 50%.

We use the device for both HO and 1/32 and I will have to say its one of the neatest pieces of equipment to analyze slot cars with. For all those who don't have one they are worth the high price they cost!

Jim Norton
Huntsville, AL

Pics Please!

Why not remove the magnets & run on 12 volts?................

Link to photos:
http://www.magnetmarshal.com/

One thing discovered in getting the cars closer in downforce is that the pick up and springs can on some cars factor in.

If the pickup shoe is concave above the spring placement (turning car upside down) the spring will push the chassis away from the track decreasing downforce.

If you slightly reshape the area of the pick up above the spring placement to be convex you can increase down force.

We had one car that we just couldn't get to come out of the high 130 gram range as measured by the Magnet Marshall. The pickup shoe mod was able to get it up in the mid 150 g range.

Jim Norton
Huntsville, AL

The link below has a very enjoyable review on how the Magnet Marshall works.

http://slotcarillustrated.com/Reviews/TechTechracing/MagnetMarshall/MagnetMarshall.html

Jim Norton
Huntsville, AL

Why would you get different magnetic downforce measurements with different bodies on the same chassis?

I've never tried to equalize stuff like this and it's never been an issue. But if it works for you and improves the quality of your racing program and attendance is strong, keep doing it.

Here is my thread on SCI about my test with a MM and discovering that in it's current design it can only accurately read my G3 magnets in the LDF position (Low Down force position)


http://www.slotcarillustrated.com/portal/forums/showthread.php?t=28855&page=4

Yo!

Jim-

I personally have only (1) SRT chassis and I think it's in the package LOL...

Perhaps you need to look at it a different way. Maybe it's not the magnets you need to be concerned with. In my opinion, "box stock" competitive racing is VERY difficult to keep even. There is soooooo much variation to performance out of the package. Tossing the cars in the ring and picking one is a great way to equalize the field, but no matter how you slice it someone will get the "dog".

Maybe another way to match the cars would be to open the class just a tad to allow a "spec" double flange rim, and some pre-approved slip-on "spec" tires with different diameters. For example- .250 double flange rims (pick you favorite manufacturer) and allow slip-ons in .340, .350, etc...

That way you can raise and lower the rear of the car to match your driving style, and it takes the hassle out of matching downforce. We were very successful at allowing a few simple, inexpensive changes like a rim and tire combo option that gives the driver something to work with. You might even be able to use sized slip-on silicone tires on the stock hub and eliminate the cost of the double-flange rim ($3.50).

Just my two cents... BTW- I have a sneaking suspicion that once the GT40s win a few races, everyone will have GT40s... LOL

-Marc and Marcus