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Ok, Friday night I decided to race a JL TJet in our Trans Am class at Whiterock Raceway. And of course running an untried chassis has it's problems. The few changes I made to the chassis for racing are as follows.
1) Limit pick up shoe travel
2) Brass heavy front end
3) Slip on silicone rear tires, approx. .370 diameter
Other than running the chassis to break it in, these were the only changes made. I had plenty of straight away speed but the turns became a problem.
It became difficult to keep the chassis in it's powerband and still mantain control in turns. Second problem was a lack of coast in the chassis. When I got out of the throttle the chassis would practically stop. But that is just a different style of driving that I am not used too.... (Yet..) Unfortunatly, about half way through the race the chassis became somwhat jerky. (Not ME, the chassis..)
And gear mesh problems could be heard. Despite the noise and problems I continued to race the chassis and finished the race. (7th out of 8) Taking the car apart after the race I found that the driven gear and or pinion gear had walked up the shaft causing the shaft and gear to bind at times.
I pressed the driven gear back into place and the chassis runs more smoothly than it did during the race. Maybe brass gears are the answer here. And I might loose top speed, but a 12 tooth gear should be eaiser to drive.....
Now what kind of expirences have you guys had with these things?
Scott
 

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Scott, two things to try:

1) Reducing brush tension will improve coast. Do it a little at a time until it's where you get it where you want it. This works whether you're using the stock JL brushes (which are pretty good when aligned) or Thunderbrushes. But before you start adjusting the brushes, make sure the armature pinion gear is fully pressed on the shaft, flush with the top of the shaft. I've found quite a few that weren't flush and that increases brush tension right from the get go.

2) Use a higher resistance controller, like 85-120 ohms, to get more usable throttle control. A JL can be run with a 45 ohm controller, but you'll only have about an inch of usable throttle.

You didn't say what release the chassis is from. Starting at around R4 the JL chassis started getting a lot looser due to more free play in the tolerances. The R6 and R7 chassis are my favorites because they finally got the brush tensioners and brush holes right and the axles holes aren't too loose. In R5 the brushe holes are too big, in R1 too small.

I'm not a big fan of the plastic gears but I haven't had slippage issues like you described. The biggest issue I have is the 3 top gears not being in the same plane. Sometimes the idler gear flops around like crazy because the armature pinion and the rear drive gear are way off and the idler is trying to mesh with both. Running the stock idler gear upside sometimes helps a little by getting it up and meshing better with the rear gear. Lowering the top cluster gear just a tiny bit may also help. I've tried using a brass idler gear but all it did was make the chassis much louder and if you check the mesh on the brass idler to plastic rear drive gear it's not good at all and I'd imagine the plastic gear would be chewed up in no time. The JL top end gear teeth seem too square and less tapered than their Aurora counterparts.
 

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At the WV Shoot-out that Gary Butner has on his monster track the main race is JL vs TJETS running the basic TJET 1"5/16 width setups and rules with the exception to the body rule that it must be an American Sedan Car though he considers the Mustangs and Camaro's sedans :) I believe his main straight away is around 28 feet and this track is very challenging with some of the best use of bank curves and some great elevation changes,

My problem with the JLs was they were so fast and loose that I had to add brake to drive this track. This was even after installing some tall boy motor brushes and maxing out the spring tension. I had to tighten up the rear end so there was no slop at all to get the brakes I needed.

I use a 125 ohm controller for all my TJETS and this controller makes quite a bit of difference with JL.

For my son Charles I built his car with a 19T Crown gear and this is about the easist mod that will tone the car down just a tad with actually little loss of top end on most tracks.

I run JW fronts on these cars and either Thunder Rubbers or LAWS on the back

Roger Corrie
 

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Mustangs & Camaros? What about the Chargers? lol Gary almost freaked out a few months ago when he found out I was tearing cars apart, mixing & matching to build the best out of what I had. He let out a BIG sigh of relief when I told him I didn't touch my main car. It's the second car I bought for myself & has won enough races to keep me from doing anything stupid like changing the setup. I added a heavy front end, foam / silicone rears, & lowered the body a touch.

Congrats on the newest addition to your family Roger!

~Kenny & Nikki
 

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