28 replies to this topic

[Big Al]

Good afternoon, gents,
 
Are there any specialists or master tuners that can shed some basics on the correct set-up of these chassis please?
 
The track used is a very has flat track recently built here in Cape Town, and this is a stock class which everyone has climbed on-board with. Rules are simple, run it out the box. 
 
So, as a first-timer when it comes to these flat pan set-ups, and coming from the "nuts and bolts" Plafit type kits, what are the important bits to know going forward, and how\what to do to alter the handling etc?
 
I\we understand basics of these things, i.e.: all plates need to be as flat as, etc., etc. But what are the tips and tricks to fix certain handling issues? e.g. nosing out mid-corner, car lipping out in cornering, braking at an angle, etc. Just some basic bullet-points of what should be done to make sure they go as best they can go?
 
Thanks in advance.
 
Regards,

Alan

[old & gray]

A good place to start:

Building the JK X24/X25 Chassis

[Don Weaver]

Check out Cheater's tome on flexi car building/set-up.

The T-Flex Tome

[VARick]

Which motor comes with the RTR kit?

[Big Al]

Thanks gents, will breeze through those and note everything inside them.

 

Rick, it's the JK 40K motor that's supplied with these. Our local club decided for all the right reasons to KISS, and so we run them out the packaging. Racing's insanely close, but, there's clearly a "right" chassis, and a "not exactly right" chassis. As a newbie, I'm in need of a cliff-face of a learning curve. 

 

Regards,

 

Al

[SlowBeas]

The above links are the best advice anyone can offer. Beyond that: Get it flat. Take your time. It takes a while – but it's worth it.
 
It's a great chassis and one that really flies. Enjoy your racing.

jb

[mark1]

Try putting a piece of strapping tape across the chassis on the bottom. Compare lap times, and how easy it is to drive, with or without tape. if rules allow, solder the motor and rear bushings in.

[MSwiss]

I was also going to suggest soldering the motor in, if allowed.
 
Preferably, away from where the motor is bolted in, to triangulate it, to keep a great gear mesh.
 
The RTR cars come with the bushings soldered in, so I have to believe that is allowed.
 
It's probably mentioned in one of the above links, but if the pan is drooping below the center, add double stick bulletproofing under the bite bar, to keep the pan level and not dragging in the back.

[Big Al]

Thanks, guys, appreciate the valuable input.

Bushes are soldered in. Motor sits on that angled bracket as pictured above. I think soldering is not allowed purely to keep the playing field 100% level. They seem rock solid.
 
Mike, I did read about adding Lexan\material below the bite bar across the rerar to avoid drooping, etc. As these are brand new, and have already been well-checked and prepared, it looks like a pancake right now. So, this thread is purely to help educate myself, and others, on what to do going forward. Should there start some strange shenanigans on the track handling wise.
 
Question: the center pan in the middle has two reverse facing clips on either side of the lead wires in the above picture. The side pan hooks under these clips in normal operation. How important is it that these have identical gaps in height off the center pan? And what might the result be of this gap not being the same? Might be in the stamping process, but the two chassis I have, these gaps were not the same. One side was definitely smaller/lower than the other side. This tells me there's a different amount of tilt occuring from one side to the other?
 
This coming Wednesday we run them and will see how they perform.
 
Cheers,

Alan

[mark1]

Part of tuning the chassis is adjusting the amount of movement it has. Tape is the quick way. Lowering the front is a big help. Flatten the braid, put the car on the track. Adjust to have about .015" clearance. Might need a cut-down guide and some shims. Should be a good baseline setup.

Those cars work real good as is. Will be fun racing.

[Big Al]

Hi gents,

 

so, further feedback and reports. First race, with the motor that came on the chassis, that was removed and binned. Terrible performance, even after a few hours of running in etc. dissapointed, same kind of issue as I had with my other 20 K JK motors..

 

Bought another motor, did a half an hour dry run in at around 5 volts, mounted it (and soldered on the top of that angled frame, and got the mesh sorted. Completely different car, and after two evenings, maintaining the same speeds, so, that seems good.

 

I have the chassis as flat as can be now, with soft JK braids plier squeezed flat, so, it's set up flat as can be. after racing, the two outriggers, whatever they are called, tab in front of the front wheels have IDENTICAL track gunk smears, about 5 mm's wide from the outside edge inwards.. no other gunk anywhere else under the chassis. so it seems the angles are even on those front tabs, and they are neither to high, nor too low, or, am I wrong? should they be worse? or should there be a lot more gunk under the chassis?

 

I'm now testing tape across the top of the chassis plates just ahead of center, to tighten up the floating movement and see if that works. The race winner laps our track at 5.9's, and I am at 6.1's, so, not really far off as far as motor speed etc goes, but, I'm struggling to solve a deslot issue mid corner, while it feels I'm doing the exact same process each lap, one lap it'll stay in, and another, 1/4 of the way round it's out and into the barrier, exact same process\braking point etc. So, would like to understand that, or what causes it? This is where my shortcoming on these types of chassis is. I am blip-braking, and then flatting it on outer lanes, and, "most" of the time it'll stay settled, but one out of 5 laps, it's out.. Grrr.

 

I do still have a bit of clearance under the rear, so don't want to true tire too flat, looking for more mileage for now. Its great fun and lap times are quick, but I get frustrated I cannot maintain fast laps or to be able to blast it round outer lanes after brakepoints for fear it's just going to come out. It just deslots when it feels like it? So, I am forced to slow a bit to keep it on, and that leaves me like 12 plus laps off the leaders.. 

 

All comments and suggestions most welcome guys.. thanks once again.

 

regards

Al

[Big Al]

And, I'm also enquiring on this article from Andy, re: the side pans should NOT rest on the center pan outriggers.. 

http://slotblog.net/...-chassis/page-7

 

Post #173

 

So, whats the correct setup, as in that same thread a few pages earlier, some guys were mentioning that they should be resting on the front tabs..

 

Whats the correct setup here gents?

 

thanks

 

Al

[MSwiss]

I do still have a bit of clearance under the rear, so don't want to true tire too flat, looking for more mileage for now.

Unless you're a magical driver, you can't expect to both "look for more mileage", and race in the front of the pack, especially on a flat track.

I'm guessing you need somewhere in the .8-1MM range, to be competitive.

Do you have more?

[Big Al]

Hi Mike, I'd say I'm in that window, possibly lower.

I'd really like to just understand what does what as far as lose vs tight does. Am experimenting with this now, trying to stop sideways movement for now, will test more on Sunday.

[Big Al]

Hey guys, some SOLID feedback.

 

Here's a pic of the latest body I just painted up for this series, purely to avoid having duplicates of the JK rtr bodies, and I always enjoy doing my own bodies.

 

Also, the Audi body I did, which I keep as a spare.

 

So, chatted a bit with Andy Brown Searle for more info after reading his PDF article on the chassis setup. Performed a number of changes, (which is a BIG problem with me, I don't change one thing at a time), so, not too sure what exactly what made it better, or if it's a combined result of the following, but, it's 100% perfect right now, and lap times are as quick as the fastest guys.

 

Here's a Pic after about 20 laps. VERY pleased with the equal gunk buildup, so I know the plates are all even.

 

Car's handling perfectly now, (for me), I can push it through the bigger sweeps and it stays put. clearance at the back is around .5 mm. All in all, very pleased with how it runs now. Roll on the next race meet.

 

regards

Al

[Big Al]

I took a couple of very zoomed in photos in order to capture how the chassis looks right now, as a possible reference going forward, should I run into issues.

Possibly might be of help for other people, not sure, but as it is now, it's 100% dialled in.

 

Here, the front, left hand chassis from the front showing the T bar clearance and the top lip clearance from the side plates.

 

 

Front right hand side.

 

Rear clearance

 

Also running the chassis with a small piece of 4 to 5 gram brass just behind the guide. Will see how we run next Wednesday.  No racing tonight, we practicing with Plafit cars for Le Mans endurance this Saturday.

 

cheers

Al

[gotboostedvr6]

Drop the front lower and make sure the front is flat across the wings. Your scrub looks like the wings might be bent down a small amount.


If it cant go lower you could bend the guide tongue up a few degrees.

[mark1]

Some other things to try- different diameter bite bar, set the front of the pans on the front ears of the center section, increase or decrease the up and down movement at the front. Try one change at a time.

[Fast Freddie]

First let me start off by saying I'm not aware of what your allowed to do in this RTR class of racing.  I do have one suggestion if it's allowed.  Install the spur gear with the big hub against the wheel and get the pinion gear closer to the motor bushing.  This allows the motor to be positioned further to the rear of the chassis and that could help handling.  Make sure your spur gear doesn't hang below the bottom of the chassis if it does it could eat up the track braid and make the track owner very upset at the very least.

 

Oh and by the way both of your outriggers are bent in their centers.  The best way I've found to fix this is to get 2 old 1/8 inch axles and place them under the tip of each outrigger and push down on the chassis directly behind the guide tongue.  It's best to do this with the guide flag removed but you can do it on a tech block with the flag installed.  One of the very first things most racers do is to make sure the new chassis is as flat as possible, the flatter the better.  That means you need a flat block, I use a piece of milled smooth granite counter top 5x7 inches but there are other things available.

[swodem]

And, I'm also enquiring on this article from Andy, re: the side pans should NOT rest on the center pan outriggers.. 
http://slotblog.net/...-chassis/page-7
 
Post #173
 
So, whats the correct setup, as in that same thread a few pages earlier, some guys were mentioning that they should be resting on the front tabs..
 
Whats the correct setup here gents?
 
thanks
 
Al

That’s a setup suggestion for the C43
You have a much older C11 and the setup is not the same

I would put some tape under the front pan tips so they Don’t get any smudge on them.
Flatten your outrigger wings - they are clearly bent - especially the r/h one looking at the pics
Take about .3mm off your ride height if you can
Get ride of the brass and use adhesive lead sheet
If it’s nosing out mid corner check the bodies for rubbing at the front and trim so they never touch
If it’s a flat track try different tyres.

Post a pic of your naked chassis from above



Sent from my iPhone using Tapatalk Pro

[Big Al]

Thought I'd post an update here, 1 year down the line.. 

Our "local" has been open Officially a year and a few months. So, we've had a regular Wednesday nite's racing for the best part of the past 12 months, and I thought Id come and update this post with some feedback. Our track, a flat, high speed road course with no banking, we run an "out the box" JK class, as our standard boxstock class. When we started, if memory serves me correctly, quick cars were as close to the 6 second mark. Sub that was considered quick.

 

Anyway, nowdays, a year down the line, we are seeing Super fast times in the 5.5 ranges, and lap counts well over 120 laps for 12 minute heats. Ive been trying to get "our" setups as best as possible, that being mine and my kid, although he's an adult, it's still a family thing.

 

So, with regards the chassis.. clearly, it's all about this being truely flat. Have got myself a decent Aluminium and Corian tech blocks, and have spent a lot more time in small pliers work and getting the center pan to be as flat as possible. zero light to protrude under the chassis when viewing from a side, and no "clicking" when tapping on various sides while holding down other sides. When it goes down on the tech block, it makes a solid thunk.. 

 

Same goes for the sidepans. I've spent a lot more time getting the front cross-over bend as even on both sides as possible, as that bend also decides the height of the sidepans in relation tot he front of the chassis. The rear is controlled as you're aware by thinner or thicker plastic or bite bar thickenesses. 

 

I've tried to get the side ears to sit independent from the center pan side ears, and the gap between the left and right side to be as close to identical as possible, but still a gap. The rub underneath dictates how flat everything is, and the quantity of rub is managed with ultra thin guide shims. 

 

I recently built a friend's chassis, including motor run in and tires trued, the entire car except mounting the body, and last night the kid finished second, and my mate's car a solid 3rd. his second time racing this class in anger. I had a tire tech issue and retired, but, all three cars are good for 5.7 5.6 lap times.. quicker now with the realization of different tyre compounds.

 

I think, for now, we're still experimenting with things like tape across the side pans and center pan, and the thickness of the tape under the bite bar. Ive learnt a massive amount int he past 12 months for sure.. We're also now preparing for this special one off SAGP event in September, and going to be using the Mossettis with Phoenix Motors etc.. should be a VERY quick laptime race, as current testing laptimes are down in the mid 4.5 second barrier.. vastly quicker than the stock JK's.. 

 

Thanks to a number of guys here for the guidance, and pointing me in the right direction.. Onwards and upwards from here. 

 

Regards

Alan  

[MSwiss]

Not sure if this counts as a setup tip, but at our Wednesday night GTP race, I was so impressed on how this car, was possibly the quietest, geared slot car, I've ever witnessed, I flipped it over, between heats to take a pic.

Probably by accident, it had a reduced friction setup, in the ARP angled pinion, JK spur, gear train.

It was the winning car.

[MSwiss]

Not sure if this counts as a setup tip, but at our Wednesday night GTP race, I was so impressed on how this car, was possibly the quietest, geared slot car, I've ever witnessed, I flipped it over, between heats to take a pic.

Probably by accident, it had a reduced friction setup, in the ARP angled pinion, JK spur, gear train.

It was the winning car.

[NSwanberg]

I don't think I would have bet on that one looking them over before the race.

[Big Al]

@Mike, 

 

unfortunately, our club is trying VERY hard to keep the class an "out-the-box" class. Angled pinions were just outlawed.. It's a challenge I must say.

 

regards

Alan