Fine Tuning The IRODs (IROCs)

I wrote an earlier article about building the IROC hot rods. That article took into account how to build identical cars based on measurements... you know, is the chassis flat, does the top plate match the chassis, are the armature Ohm readings close, are the magnets matched and close in strength etc. If you would like to catch up and read about that you can do that here. Well as good as that sounds that's just the basics... there is more and that is the fine art of tuning the IROC chassis. If you're interested then click the read more link below.

This article is about what I encountered and learned so that the IROC hot rods actually ran close. Being built close and running close is a huge difference. I was careful when measuring and assembling the chassis. I used the same chassis, matched top plates, close matched magnets, close arms, same brushes, pick up shoes and springs, axles, wheels tires, front ends... I think you get the picture. Even though I did all this the cars were all different when tested on the track. Some were fast out of the gate... others were mediocre and others were just down right dogs when testing on the track. So now the real work began... how to tune them to run close.

The first thing I did was adjust the pick up shoes. What I found out was the closer I got the wear pattern on the pick-up shoes to match between cars the closer they ran. They were closer but not there yet there were other issues lurking.

After I got maximum pick-up shoe contact and consistent wear pattern I then worked on restricting the shoe travel by bending the front of the pick-up shoe. Well after I did that I had to re-adjust the shoes again in order to create maximum contact and consistent wear pattern... That was a lesson is patience and persistence...  :-)  NOT! But it did yield better and closer performance on the track. 

I had lapped the gears and I had two cars that were more noisy than the other two. So after looking at the chassis really close by turning the rear wheels and just watching what was going on with the gears, arms etc... I found that the front magnets on the two noisy chassis were actually moving (loose) in the chassis. They were moving back and forth much like an antique clock pendulum lever. You could also hear a significant difference between those that had this problem and those that didn't. 

So I had to search for two replacement magnets that were of close strength with the other magnets and that did not move in the chassis. When this adjustment was made I now had three IROCs that were running pretty close on the track. So now I still had one that was significantly slower. Again I took that one car off the track and tried to look at it closely. After a lot of frustration and observation I noticed that the armature shaft was actually touching the body when the chassis was mounted on the body. That said I took the body off the chassis and used my Dremel and remove some plastic from the body so the armature shaft did not touch or bind on the body.

When this was fixed ALL the IROC hot rods were now running pretty close with respect to lap times. It was amazing how their times were close, their responsiveness was close and they even sounded close as they were going around the track.

This was a lesson in how tuning is just as important as building. I would highly recommend building several IROC car sets. The more you build the more you notice and learn!! Happy Building/Tuning!!! :-)  

If you would like to see the race report of their debut M.A.S.C.A.R race click here.