Hobbyist Forums banner

Fray car tuning

87K views 288 replies 57 participants last post by  wheelszk 
#1 · (Edited)
Hello all,
My name is Tim Leppert, Iv'e been racing fray style cars for seven years. and been to every fray since 2001.
I thought I would try to get you going on building a fray car from the ground up.
If you have a few tools, and a decent supply of parts, you should be able to build a pretty good fray car.

First things first:
Tools,
You will need a fast way to remove gears. The R.T. gear removal tool is the answer
The R.T. gear press is also a required item. No better gear press made. Don't even bother with any others.
Wheel removal tool.
Good wheel press, Wizard makes a good one, and at a decent price.
Poising tool, You can make your own, just go to H.O. world for the article.
Tech block. Yes you will NEED this, (not just for tech)
Cheap dial calipers, A decent set can found at Harbor freight.
Other stuff after I think about it......

First up, Chassis choice.
You want to find a chassis that is flat on all four corners.
You will need:
Your tech block, two drill blank axles, uncut (about 2" long) and ALL your chassis (stripped of all removable parts)

Simply place the axles thru the rear and front axle holes and place on the tech block so that the ends of the axles are resting on the rails.
press on the corners of the chassis, and find the ones that are touching on all four corners.set these aside(they are very rare)
then begin to rate them based on how far out they are. place them in a line in order of straightness.

Next episode: Gear plates.
 
See less See more
#2 ·
I supply specific sought after parts that the FRAY guys need.I am probably the only dealer that will sell the hard to get gearplates,arms and such.Sorry to hijack your thread,just wanted to also help out the newbies and soon to be tuners.
DRAGjet
859-356-1566
 
#3 ·
Gear plates and matching.

In this episode we'll cover two things, Choosing a gearplate and matching it to one of your chassis.

Gearplates:
I will admit to being lazy when it comes to gearplates. If I find one that fits a chassis well, I use it. I don't care if it's a lettered plate or not.
I never try to match a certain plate and chassis by number or letter. I just check the fits that are important to me.

What I look for is:
square topped Idler posts.
rear hole is not too big.
no cuts or grind marks that deam it illegal for the fray.

To prepare for the fitting process, you will need to dissassemble your plates. If you have any plates that read "pattent applied for", keep these gears seperate from the others, they are very early, and usually have better machined geartrains.
As an aside, I do not recommend removing the nine tooth from the shaft, if it's tight, leave it on!

When you have your pile of gearplates, it's time to start checking fits. This is easy, when you get set up.
You will need:
Your tech block,
The 2" long axles you had before
a gearclamp band, (not a tight one!)

Now take you best chassis, grab a plate and assemble it with the band. Install the drill blanks in both the main bearing holes and the cluster gear hole. They will be sticking out the top and the bottom.
Now turn the chassis so that the drill blanks are horizontal. and place it on your tech block the same way we did the axle holes.
They will not touch the same way that the axles holes did. but we are looking for the closest to touching all four as we can get.

Remember that feel and repeat with all the plates you have. When you find the top three or four plates, save them as your top matches and we'll move on to choosing the arm....
in the next installment.

Thanks
Tim Leppert
 
#4 · (Edited)
Arms

Choosing the right armature

This is were it gets interesting.
To find your best armature, we have to define "best". My definition is smooth, and fast in the midrange. Lots of folks look for that punchy, rip your throat out armature and all they get is dirty tires. The fact is that you need to difine your driving style and choose arms accordingly.
The other thing to remember is that with the tools available now, you can switch arms faster than rear tires. So if you have a doubt,pull it out. Try another one and see.

OK here goes,
you will need:
1 set of blue and yellow magnets.
1 set of old crappy pickup shoes.(try M/T shoes for this, they don't need springs)
1 set of decent brushes, cleaned and polished.
a power supply at your bench.

Now the trick here is that you have a number of chassis, and a number of plates, now your'e throwing in more stuff like arms.
Try doing one thing at a time and start with the chassis and plate combo you think is your best.
Assemble the shoes and the magnets, then slip in the brushes, and pop in the arm.
Spool 'er up and listen, remember that tone!
Then turn the chassis the other way and run it backwards. it should run faster forwards than backwards. If not, no worries, we can fix that later.
Next,try switching plates. (remember the plate you just tried, you will probably end up with that one) You will hear a difference.When you figure out the the original plate is the best, mark the chassis with the plate # and the plate with the chassis #.
Next thing is to try all those arms and find the one that feels and sounds the best. Set that combo aside.
Now you can grab another chassis and start all over and find the next best combo.

Next installment:
brushes and brush tensioners.
:woohoo:
 
#11 ·
You know... I'm not trying to be funny here but would someone PLEASE explain what the heck a fray car is? No really, I'm not kidding. I've heard alot about these but what's so great about this car that I can't get with my SG+ or like a wizzard or something?

What does it look like? Is this based on something else? Does it cost an arm and a leg to make? I paid $40 or something like that for a wizzard awhile ago and I thought that was a bit high so any insight here would be helpful.

Thanks,
Xence
 
#12 ·
A fray car is a T-jet with an independent front end at 1 5/16" in width, typically a drill blank of 1 5/16" is used for a rear axle and silicone over sponge tires are used. The arm can be trued and balanced and each pole must not ohm lower than 16.0 on average. Resin bodies are used that have been lightened and lowered, also the newest thing is to use CNC'd gears as they are perfectly centered and straight and enables you to not have to go through dozens of stock gears to find the perfect fit. I'm sure more will add but that is the basics of it.

If $40 is a lot to you, don't bother with this car type, or much else that goes beyond stock for that matter.

The great thing about these cars is that they are not blindingly fast, but they are a heck of a lot of fun to drive.
 
#13 ·
I'm not against spending more than $40 but I would need a place to race this little devil. As it is now I can't say that I know a place here in ct. that races. I know there was a group of guys out here somewhere but I know they were at least an hour away. Normally I wouldn't mind this but I drive an hour each way to work every day. I really would rather not drive even more than I already do. I'm not deadset against it I would just rather not.
 
#14 ·
hey glenn

check out this website, and look at the section where the bodies are sold. it shows lots of examples of fray cars.

http://www.moonstonebodies.com/modern_car_bodies.html

also check out the fray (the race)

http://howorld.fsmra.com/archives/fray/fray/pgfrayst.html

yes, you could spend less and go faster, but for me fray cars are suich a kick because they are really tweaked for maximum performance. a big block chevy or ford in stock trim will blow away a tricked out VW bug, but tricked out VWs are still cool. at least ot me :)

if you have any experience with stock tjets, its frankly amazing how fast a really well built fray car is compared to stock tjets
 
#16 ·
Most of the TJet races I've been to also run a round of stock TJet races, so the stock form bodies and chassis are still represented. The Fray/VHORS style cars really grow on you once you realize just how much fun and fast they really are. I see them as really tricked out TJet Race Cars that would probably be something between a super stock and a modified in 1:1 racing. Since they are Real Race Cars the aesthetic concerns are allowed to take a backseat to the performance ones. I'm totally cool with their looks and even more so when racers trick them out with nice paint and decals.
 
#17 ·
I agree with twolff that they are really sorta odd looking. Now having said this I am NOT against doing this sort of thing even if the car costs me $100. I don't want to spend $100 a week on a car but if I jump into it and I end up with a few of these devils that I can race with .... so be it. I'm cool.

I get back to the forementioned problem, and I'm working on fixing this now, of a nearby place to race. I've got another post going as well on 12'x4' track. Hopefully this will come to fruition and then maybe I can get some people over now and then and possibly even get to a place where we race these fray cars.
 
#21 · (Edited)
OK Here we go:
You will need:
The radio (AM and tuned to no station)

A power supply rated for 18-20 volts. Pluged in to the same recepticle as the radio.

Your parts and pieces

a small, sharp pointed probe, or toothpick

a set of sharp pointed tweezers.

some Wizzard brand brushes (do not scrimp on these. They are the ONLY brushes I use)
polish faces on a peice of paper setting on a hard, flat surface.

OK
Find That good chassis, throw on some shoes and let's get to it!

First, make SHURE you know which direction your power supply is running. and were to place magnets for proper rotation. the best way to do this is to take a car you know runs in the proper direction and test the supply.
the arm should rotate clockwise when all is right.
THIS IS IMPORTANT!!!!!!!!

Now that we have that done, let's start testing.
Grab that good plate, an arm and brushes, assemble with clamp
spool it up and remember the tone. Then turn the chassis around and spool it it up backwards, you should sound better forwards than backwards.

Don't change anything yet.

We want to "seat" the brushes.
We do this by getting the arm running and pressing the brushes against the com, GENTLY.
Try to stand up the chassis and get it running and use the toothpick to do this. Press in the center of the valley of the brush tensioner. You should feel the brush directly thru your fingers.
you will hear the revs go down a little,then release and repeat. don't allow the arm to stall when you do this. This should gain some revs for you.

The next thing to listen for is spinning brushes.This is something you don't want.If you have a good solid tone, your good.
if it sounds like you are slightly changing the position of your controller, you have a brush spinning.
To stop this you will need to scratch an "X" in the bottom of your brushes. then reseat. this should correct the problem.

Now we get to the good stuff.
If your arm spins faster in the proper direction (clockwise) skip this next step.
If your arm spins faster anti clockwise, then we need to correct it.

Remove the arm but not the brushes. Align your chassis so that you are looking from the back to the front, you should be looking at the front brush.
The right side should be higher than the left. To do this, remove the brush and grab the "v" with your tweezers from the side you want to be higher.
GENTLY tweek it up, and replace the brush and inspect.
this is a very delicate adjustment so go slow.
Simply turn the chassis around and repeat for the back brush. Try to get them looking the same.

When this is done to your liking, we will move on to adjusting tension. There are many ways to do this, and I will not get into all of them here.This is my favorite method,
Remove the arm and brushes. Looking from the top, place the toothpick in the valley of the tensioner and gently push up. this will bend the spring at the root of the "v"not back by the rivet. Do this a little at a time, checking your progress with the brush.


But try this test first.

Turn on the radio, turn the station selector to a spot were there is no signal.
Now spool up your chassis. You will hear the static change. This is a poor man's ocilloscope. It will let you know how efficient your little motor is running. As you play with the brushes, adjusting and changing, you will find that the static will get louder and softer, depending on your adjustments.
The quieter you can get the signal, the better your arm will perform.
You will also find that certain arms are quieter than others in that chassis.

Avoid over adjusting the brush tensioners. they are very delicate. if you get into trouble and bend one the wrong way, you can save some of them by making a little lasoo out of dental floss and pulling it back.

Never try to add tension with the chassis assembled. always remove the arm and brushes.

When you have it close, start changing out arms, looking for the one that sounds good.

Good luck! :wave:

Next installment:
blueprinting the geartrain.
 
#22 ·
One silly question Afxgns, do you put the "X" on the brush towards the tensioner or towards the arm? I did this only one time cause I read about it somewhere else and I believe I put it towards the tensioner to keep it from spinning? Is this right? One thing I noticed was the car ran slower but I didn't do all the tweaking you mentioned!! Now will have to go back and do it right!! Great freakin' thread you got going here Afxgns!!!!!!!!!! Keep it coming!!

Oh, could you give a quick explanation on why you "X" the brush and its benefits!! Pleeeeeeeeeeease!!
Thanks,
Tom
 
#23 ·
The X is put in the brush and placed down towards the holder and away from the arm. This way the brush is seated in the groove and won't spin when the arms spins across it. If the brush spins you will lose power and thus lose speed. Sometimes with the Wizzard brushes since they are really tall you may see a bit of slow down because you now have too much tension on the arm, sanding them down lower will reduce that tension and it should speed back up.
 
#24 ·
Marty has it right,
Put the "X" on the side towards the tensioner.
If the brush is spinning, the acceleration is inconsistent. But the main reason is your braking the alost gone. Also, the brush will actually wear the tensioner in two, if you let it.
 
#25 ·
martybauer31 said:
The X is put in the brush and placed down towards the holder and away from the arm. This way the brush is seated in the groove and won't spin when the arms spins across it. If the brush spins you will lose power and thus lose speed. Sometimes with the Wizzard brushes since they are really tall you may see a bit of slow down because you now have too much tension on the arm, sanding them down lower will reduce that tension and it should speed back up.
Thanks Marty, much appreciated!! :thumbsup:
Tom

Marty has it right,
Put the "X" on the side towards the tensioner.
If the brush is spinning, the acceleration is inconsistent. But the main reason is your braking the alost gone. Also, the brush will actually wear the tensioner in two, if you let it.

Ditto to you Tim!! :thumbsup: KEEP IT COMING!!
Tom

P.S. Tim...Kinda lost translation of this.."But the main reason is your braking the alost gone" :confused: :)


Question...How do you put multiply "Quotes" into a reply :confused:
 
#26 ·
Fat finger Freddy stikes again!

There are lots of reasons NOT to have brushes spinnig.
But the main reason is, how much braking you loose.
Traditionally, Fray cars don't run a brake wire. So all your braking has to come from the car. Either the geartrain or the brushes.
With the advent of the RT gears, your brush settup is even more important.

I Hope that covers it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top