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More rookie questions - chassis setup


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#1 Rich Joslin

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Posted 30 November 2019 - 02:01 PM

Let's stipulate to the fact that the biggest improvement in my racing will come from more practice.

Let's please also stipulate that I get good advice from Jeff Eve, the owner of Fantasy and racers like Dave Buchholz, Dave's son Rich, Pete Varlan and Mr. X who run in the same Tuesday night class but I would like all the input I can get. Perhaps your comments in this public forum will help more than just me.

 

We race the ProSlot 16D 2002 motor typically on a JK 21 chassis. Mine has 12/36 64 pitch gears. I am keeping my tires between .690 and .720. The track is a 145' Euro Hillclimb.

 

I am so new that when someone asked me how my car felt after cutting and truing the tires down from .765 to .720 I honestly didn't have a clue because I didn't know how it should feel. So at this point the same is true when it comes to getting the most handling help out of the chassis. I've read about the importance of a flat chassis, the angle of the guide tongue etc so my question today focuses on taping the chassis. I see racers with tape across the back, tape across the front, one suggested a shorter bite bar to allow for pinching out the side to side movement while keeping the front to back motion.

 

Would someone explain what handling issue are you trying to correct by putting the tape in one location or another? Is there a specific adjustment that would help navigate the dreaded donut? Dreaded by me at least! Other "tips" I've found here included offsetting the wheels a bit, specifically for help in the donut and taping in a way to limit only half of the side to side movement. I understand that I will have to experiment no matter what to find what works best for me but I am hoping for input on what "change" in handling I should expect with the different approaches so I can begin to define how my car "feels."

 

Thank you!






#2 Terry

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Posted 30 November 2019 - 02:43 PM

Are you required to run the JK 21 chassis?


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#3 Rich Joslin

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Posted 30 November 2019 - 02:59 PM

Are you required to run the JK 21 chassis?

 

My understanding is it can be any stamped steel chassis with the "small" motor hole. I believe most racers are using the 21.



#4 Pablo

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Posted 30 November 2019 - 02:59 PM

Here is a build thread I did on a chassis and car similar to yours, you may find some good tips that apply to you in it:

 

http://slotblog.net/...tralight/page-2

 

As far as taping the chassis, it's done to tighten up the amount of chassis movements. I'd recommend starting with no tape and tighten it up little by little, noting your lap times and if it makes the car handle better for your driving style....

 

As far as the red dampening tape, it's used to reduce vibration. Hold the car sans body in your hands, power at 3 volts, and note which parts of the chassis are hopping around the worst and place the tape there.

 

Don't forget to read Cheater's famous T-Flex thread. I't not a JK chassis but it still has a ton of good advice for any flexi

 

http://slotblog.net/...he-t-flex-tome/


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#5 Rich Joslin

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Posted 30 November 2019 - 03:48 PM

Hello Pablo,
 
I just finished all six pages of your "GTP Ultralight" build. Certainly very interesting for me. I didn't understand everything but more than I expected thanks to your thorough narrative as to what AND why.
 
I had previously read portions of Cheater's T-Flex Tome and found helpful information there as well. 
 
So much still to learn; as long as it remains fun I'm in.
 
Thanks!

#6 slotcarone

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Posted 30 November 2019 - 05:17 PM

Rich if your car handles well I would suggest you  concentrate on driving an entire race with minimal deslots at what is a good speed. Most of the things the top guys are doing will not change the handling of the car much at all but they are looking for those tenths of a second that the top level racers need. As your driving/racing skills increase so will your tuning skills. :)


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#7 Rich Joslin

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Posted 30 November 2019 - 08:23 PM

Thank you for weighing in Mike. I know you are correct. With my interest running so high right now it is difficult for me to stay off the forums which leads me to multiple "what ifs?" I find my time between visits to the track dominated by thoughts of slot cars and racing.
Though he always indulges my questions and provides thorough answers I know Jeff believes my focus now should be limited to learning the track and how to drive it. He refers to "the window" being the time between braking and getting on the throttle and how each driver has to find the "windows" that work best for them. Hard to argue with his advice or yours Mike. Sometimes I just get ten steps ahead of myself.
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#8 gotboostedvr6

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Posted 30 November 2019 - 08:31 PM

Once you get more comfortable with racing i'd find me a .025 C7 to test. It is way faster then a C21 because it weighs a whole lot less.
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#9 Dave Buchholz

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Posted 30 November 2019 - 10:56 PM

Are you referring to a JK C7?

Is that a typo? A C7 is a drag racing chassis.

The requirements of our group is the motor must sit ON the stamped center pan, not in a motor box. An example of a chassis that does NOT qualify is a JK C43, as the bottom of the motor is level with the bottom of the pan.

A Parma Turboflex 2 would qualify, but will take a butt whoopin' from the JK.
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#10 Danny Zona

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Posted 01 December 2019 - 12:07 AM

The JK Cheetah 7 was used in all of flexi racing back in its heyday.
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Test, test, test and go test some more.
You're never fast enough!!! 💯

Preparation leads to separation.

Luck is the residue of design.

KELLY RACING 😎

#11 wjtaylor

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Posted 01 December 2019 - 01:45 AM

Taping of the chassis will vary from week to week. Sometimes it's pans forward, sometimes it's pans towards the back. Sometimes the tape is at the front, sometimes it's at the back by the cross bar. Sometimes it's no tape at all! You have to go thru all the possibilities every week.

 

You mentioned guide flag angle and that is very important. Don't forget to check it during the race.

 

Also ride height. At the back, cut the tires so you have the minimum allowed clearance. At the front, remove the guide spacers until the front of the car touches the track and then put one thin one back in. The difference in the way a car handles between a .690 tire and a .720 tire is enormous. And make sure you have rounded the edges enough. To many guys are running to square.

 

Is your body mounted in the same location fore/aft as the fast guys? What about the height in the back? And don't let the nose drag on the track when you are running.

 

Have you replaced the bite bar yet? On the JK C11, the bite bars are poor quality and we replaced them with piano wire. Yours will probably be the same. And don't forget to try different size wire while you are at it.


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#12 Rich Joslin

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Posted 01 December 2019 - 08:53 PM

Thank you for the easily digestible advice. Bill.
 
I went to the track to practice before reading your post. Fortunately a very knowledgeable racer/builder I will henceforth refer to as Mr. T was at the track too. He had read your post and took the time to discuss with me many of the points you make as he felt your advice was very good . It was helpful that he could explain some of these things while using my car to demonstrate. 
 
We discussed a great deal of technical and setup details but he repeatedly reminded me that "I wasn't there yet" meaning I needed to focus on learning to drive the car before getting carried away with too many tweaks. 
 
We worked on adjusting the borrowed controller I am using to better suit my driving style. This made a big improvement in my ability to get the car through the donut and around the track with the confidence I needed to go faster in certain sections. After telling Mr. T about my discomfort with not being able to see my car through a significant portion of the donut when on the black lane he described how he handles that section on that lane and when I adopted his method it was a significant improvement for me. 
 
We kept the chassis tweaks to a bare minimum, two small pieces of tape near the back to limit some of the movement. After making the adjustment I went back to the green lane that I was running earlier to see what impact the change had on my lap times. What I noticed was the car being tighter in turn one which allowed me to feel comfortable carrying more speed into it. My best lap improved by .15 and in general my lap times were more consistent.
 
At the end of the session we discussed tire size and clearance. Right now my tires are at .695 and I am just at the required .47 clearance. With my gearing this gives me a roll out or final drive ratio of 4.32. 
 
I have not changed the bite bar but we did discuss that and I will be out looking for some piano wire tomorrow so that I can do so.
 
It was a very productive session. I expected to be there one hour and it turned into three hours but worth every minute to me, though my wife was none too happy!
 
Thanks again for the solid advice Bill. 
 
Thanks Mr. T for taking the time to help a Rookie.

#13 wjtaylor

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Posted 01 December 2019 - 09:48 PM

Rich,

 

You are welcome. I am glad that my advise was of value.

 

I read thru all the replies to your two posts, all good stuff. I have been thru all this stuff with the new racers here at Buena Park.

 

I would like to add two additional items. First, watch how all the fast drivers hold their controllers. You will see that most of them use 2 hands. One to work the trigger and one to hold the controller. Using 2 hands is important. The other thing is, you are not racing the other drivers, you are racing the track. Don't worry about what the racers in the other lanes are doing, it is absolutely immaterial to your race. If you and your car can get 40 laps on green, get 40 laps or as close to it as you can. If you overdrive and crash, now the best you can do is 39.

 

As you are getting started always remember to be polite to the faster racers on either side of you. Ask them to let you know when they are coming. You will be to busy driving and focusing on your car. The faster guys will have better track awareness, let them make the call. Someday soon, you will be up to speed and you will have the better car and you will be asking them for a let by. AND IT FEELS GREAT!


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#14 wjtaylor

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Posted 01 December 2019 - 09:55 PM

Rich

 

I just noticed Rochester. Went to school at RIT


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#15 Rich Joslin

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Posted 02 December 2019 - 12:08 AM

Nice! RIT is a great school.

#16 Racer36

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Posted 02 December 2019 - 09:38 AM

Once you get more comfortable with racing i'd find me a .025" C7 to test. It is way faster then a C21 because it weighs a whole lot less.


The JK Cheetah 7 with the pans flipped was the hot setup at Fantasy for a long time. The .025" version was only good with a S16D in GTP.
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