# T-Jet tuning



## BewstdGT (Jan 4, 2005)

I didnt find the kinds of answers searching so maybe you folks can answer some questions. Im not a competetive racer, I just tinker on my own personal track. The track has some banking so I was never a fan of trying to limp my tjets around and watching them deslot every 10 seconds. I only own one new autoworld tjet car. The first thing I did was grab some sticky silicone tires for the rears but that really didnt help much. The chassis seems to bounce around a lot on the track and that causes it to deslot more than anything. I snipped the pin down just a bit and that helped some. If I remove the front tires it actually tracks decent but I know its not the best way to get the car to work. When I put the tires back on its right back to crappy handling and bouncing. Ive seen guys at the tracks using the wide front axles with the small tires, usually a gold colored wheels. Is that the only good upgrade for the front axle/wheels? I have never really gotten heavy into the tuning of these cars because Ive never needed to until now as most of my collection is magnet cars and with silicone tires they are glued to the track. I just wondered if anyone had any good recomendations on getting rid of the bouncing as well as maybe some links to sites that talk about tjet tuning. Any help would be appreciated. Thanks!


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## Bill Hall (Jan 6, 2007)

GT, Here's a few quickies

Check for bent axles or wheels that are off center, this will make your car bounce all the time. Run your car at very low speed and look at the wheels...if the're oscilating or wobbling around like the Hypno wheel on the Twilight zone ...replace them. Most serious guys ditch the "Playdough" stock rear axle. 

Scuff those sticky rear sillis and make sure the contact patch is even and clean, one piece of crud can make things hop around. 

If you havent checked, trued or replaced those stock front tires and wheels ...do so. By lifting the rear wheels slightly and gliding the car in the slot ...you can feel if the front wheels/tires are lumpy or wobbling. By then lifting one side or the other you can isolate left and right. 

Still hopping, but now only during launch? If it's bad you'll have to take a bit of spring out of the front...Sometimes if the bounce is not too serious you can open the shoe hook curvature a bit where it inserts into the hanger plate which affects springing as well. Opening lessens the pressure and closing increases it. It should be noted that this technique is not a subsitute for proper spring tuning...I use it more as a gentle final adjustment.

In a nut shell, subject to pencil whipping and flogging by our membership, I usually go like this.

With the body on, check for tire or wheel rubbing or gearplate to body interference. Also check that the pick up shoe windows arent binding on the body or chassis. Roll the car on yer hand and learn the feel.

Also check the chassis by itself by again rolling it on yer hand, if it's binding isolate the source and fix it.

Run the armature by itself...gently...ya dont gotta get all winga ding ding with it ...just ensure that it responds good to throttle input and pipes up...a good one will sing.

Make sure all your tires wheels and axles are perfectly round...tires clean and axles lubed...dont forget the front axle!

Once you've got a roller that pipes up on the test station you can start to work on actual track tuning. Let us know how you do and what you find.

I recently went through a pair of AW ultra G's for a buddy, one had potential the other was a turd. After little tinkering one was a rocket and the other was at least mediocre. The good the bad and the ugly LOL. My self I like to quickee lap all plastic gears with ultra bright toothpaste. Shuts those noisey buggers up and loosens the gear train nicely. The added benefits are water clean up and the cars are minty fresh! 

Theres plenty of sites out there to browse they all have their merits. Like many of our membership I dont advocate throwing hot rod or aftermarket parts at a troublesome car. I like to get a smooth stock ride and then build from there.

I do advocate getting some spare chassis to play around with, the A-Dubs are cheap enough. It'll help you to establish a frame of reference and a feel for these chassis. The poopy gearplate syndrome is a recurrent theme with these cars especially in the driven cluster/pinion area. Just swapping to a good gear plate can take a lot of twitch out of the chassis.


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## BewstdGT (Jan 4, 2005)

Wow talk about a load of good info!

I like your idea of maintenance FIRST, then throw the mods at it once its running good in stock form. And I never thought to try the abrisive toothpaste to seat the gears so I will defintely do that since it sounds like a sloppy ratchet as is heh. This one actually does have some decent speed compared to the stock t-jets I have seen before so I think Ive at least got a decent one to start. I'll have to sit down and tinker some more with your recommendations and see how it goes. I'll let you all know. Thanks for the help thus far! :thumbsup:


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## twolff (May 11, 2007)

Check that the knurled rear axle is not hitting the bottom of the chassis. I've seen that mentioned elsewhere and the poster noted that the AW Ultra-G chassis has been "notched" above the rear axle to help ease the problem. There's been a lot of axle slop in all the JL and AW chassis I've run ~ 3 cases worth. The AW Ultra-G has had the best fit to date based on the single chassis I've seen.


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## Bill Hall (Jan 6, 2007)

I'm somewhat on the fence regarding the axle slop thing. The AW's start around a whopping half a MM! Do I like it for a serious racer? Well heck no! Is it critical to a runner type car?...not so much. Some of my favorite cars are sloppy old T-jet nags that are smooth as silk. Swamper Gene has a nice little diddy on his site regarding the AW axle flute to chassis interference deal, complete with pics and hyroglyphics so even a Maroon like me got it fingered on the first read. Clearly the axle hole tolerance has overlapped the axle to pinion plate tolerance. 

I also tend to agree with Swamper that once under load the axle slop issue is a minor thing for runners. "Self leveling/settling" for lack of a better term. 

I also neglected to add that if the clown gear issue becomes intolerable I am not remiss to installing the T-jet brass final cluster. Something I saw Noddaz do a ways back. It should also be noted that pinion shaft journal in the chassis needs a light reaming to accommodate the T-jet pinion shaft. On occassion a spacer is required to drop the pinion down in order to provide a proper mesh on the crown. It's not uncommon to have to toss the original crown gear as well. Just kinda depends on the individual car and how far out of bounds the gear rack is.

Certainly not a mod for everyone, but my pile of gears is substantial enough to dabble and see what can be had.


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## mking (Apr 25, 2000)

Bill Hall said:


> if the clown gear issue becomes intolerable


God those clown gears crack me up. 

Ever go to the circus and see 15 clown gears walk out of a T-Jet VW bug?


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## LeeRoy98 (Jul 8, 2005)

Stop it... laughing... can't breathe....


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