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I recently purchased a 'PCS' chassis from eBay, and have constructed it to fit under an old Scalexteic Mustang shell. Initial performance wasn't to bad, but it had a tendency to tip in corners. So I placed some weight immediatly in front of the 'chassis', attached to the guide holder section, which went as far the guide. Performance was ok, but not brilliant.

I wanted your advice on tuning one of these chassis? I run on a wood track at home. The front axle has had the other small tabs glued to each side of the chassis, to stop up & down play.

Any advice would be great,
Chris
 

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Great topic. I have one, under an OCAR MGBGT, and I never really got it going. There are certainly a lot of these around but the challenge may be that they are under vastly different bodies ranging from prototypes to salons and resin to plastic. Also, the running gear will vary immensely.

Isn't the rule of thumb that if the car tips, add weight down low and if the rear slides out, add it up high?
 

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Tony Condon
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Hi The pcs chassis isn,t too sophisticated ,but one way i have found that improves the performance is to make the front axle rigid
I do this by removing the silver steel axle from the chassis and clipping a piece of 3/32 bore brass tube in its place
the tube is 1/8 od which means that the chassis clips grip it tightly .note that the tube is the same length as the axle fron the inside of the hubs
Nest slide the axle back into the tube ,re attach the wheels and the front end of the chassis is instantly stiffer and less likely to tip out

cheers tony
 

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fred
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I have modified a few of these chassis which I have used for various proto and GMC kits.

I firm up the front axle as described by superhornets, but I also use small plastic box sections (found in hobby/ craft shops) glued to the sides of the chassis.

I then add lead to the underside of these box sections. I find this gives me a better distribution of weight to the chassis.
 

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Have a look at this article to point you in the right direction:

http://www.freewebs.com/atadd/howtobuildaslotcar.htm

Cheers

John
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This www is also the one where I got my info how to tune a PCS and I have a few at the moment.

In most cases 5 gram in front is enough but some cars (ref my Porsche 914) need extra weight as suggested in the www

Greetz Frank
 

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A little off topic but how is the Slot Classic chassis different from the PCS chassis? The look very much the same if not identical.
 

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The PCS32 is an endbell-drive version of the Slot Classic which is can-drive.

Something I find with PCS32 chassis is that the rear holes for the axle bearings are not always aligned very well (probably due to warping of the chassis when ejected from the injection mould). If you get one like this, open the bearing holes out with a round file and then Araldite the bearings in rather than rely upon the holes to keep them in place.

For ballasting the PCS32 you can add styrene right-angle strip to the external sides of the motor mount allowing for lead to be place low and further out than the chassis normally allows - I think there is an "official" kit to add this to the chassis as well.

Coop
 

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This works for any 1/32 car, any chassis. Measure the distance from the guide post to the rear axle. Multiply the distance by .715. Mark that distance on the chassis; this is your center of balance. Make a loop with thread such that you can wrap it around the assembled car at that point so that the car is supported by the thread. It's likely that the car will tip to one side of the center of balance. The idea is to add the weight such that the car is evenly balanced on either side of the center of balance. This will improve the performance of any car or chassis.
 

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Ey Up Stumbly.

Can we have an explanation of a magic formula that applies to " any 1/32 car, any chassis ", please ??.

Front engine, rear engine, in-line, angle-winder or side-winder ??!!.

And, is the resultant measurement from guide or from rear axle ?.

vbr Chris A.
 

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The measurement is always from the guide post.

Measure the distance from the guide post to the centerline of the rear axle (d), multiply that by your weight constant © [.715] to get the optimum center of mass for the added weight (w). So, d x c = w

Then you do the trick with the looped thread around the body at (w) to determine where to add weight to achieve the proper balance for the car. Weight should be added to the bottom of the chassis, if possible (clearance rules may apply).

This should work no matter what the drive configuration of the car is, inline, sidewinder, anglewinder, etc. The reason is that you're balancing the entire assembled car, not just the chassis. Of course, we're talking about non-magnet racing here, though I imagine that if one added weight using this method to a magnet car, performance might improve, but why would you need weight with a magnet?
 

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QUOTE (Chris Byres @ 2 Jan 2012, 11:01) <{POST_SNAPBACK}>Initial performance wasn't to bad, but it had a tendency to tip in corners. So I placed some weight immediatly in front of the 'chassis', attached to the guide holder section, which went as far the guide. Performance was ok, but not brilliant.
That sounds like a good start.
Cars that are tipping usually benefit from a lower c of g and /or wider track.
In some cars the smaller diameter tyres/ mounting the body lower / wider track has been taken as far as you can, so weight low down is well worth a try.
Front / rear weight distribution is worth playing with. In a lot of cars moving the c of g further froward if its tipping (and moving it further back if its sliding) is worth a try.
The chassis specific ideas mentioned above are well worth trying. There's no one size fits all answer. All of these depend on tyre grip, track conditions and driver preference so be prepared to experiment.
 

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Hi Stumbly,

thanks for your response, but what I was asking for is the derivation of the universal weight constant ( 0.715 ) ??.

vbr Chris A.

ps: As a professional Engineer, and slotracer for 40+ years, I have never heard of such a thing !!.
 

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Chris, I understand your concern. All I can say is that the formula was derived by the top racer in our club, based on a number of experiments he'd done with the cars in his stable...including inlines, sidewinders, and front-motored cars. He had also been a successful 1:1 racer in the past, and apparently used some of that experience to derive his formula as well.

All that being said, I've applied the formula to my own cars (all of different configurations), and it does seem to work wonders. Why the .715 constant works to derive center of mass is beyond me, but it works.
 

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The percentage of the car's weight on the rear wheels makes a differance. Yeh agree with that.
So it follows there will be an optimum percentage for each car in each set of conditions.
Yes I try different weight distributions. Not by aiming at any specific ratio, just testing to find what makes each car produce the fastest lap times and what could be driven consistently fast.
So measuring some of the cars where I've found the optimum....
I have found the .715 ratio is about optimum for some cars in some conditions but it is some way off the optimum for some cars, and the optimum is not the same for all conditions.
What ratio has been found to work on a PCS chassis? Yes that would be a useful to Chris. Unfortunately the concept that there is one optimum ratio that suits all 1/32 cars whatever chassis they use is flawed.
 

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Ey Up,

Are you being facetious, or just offensive, "Yes that would be a useful to Chris", Really ??. You think ??.

Please think again before making such rash judgements.

vbr Chris A.
 

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Ey Up,

For your information, I won the PCS saloon class at Wolves last October, so I possibly know how to set up a PCS chassis.

I had 5gms just behind the guide, and 6gms each side to the rear of the "side pans".

25k Scaleauto motor on 9:26 Slotit, SlotPlus alloys, NSR 19x10 Ultras. Scaleauto guide, Slotit Independent front axle, in brass tube.

One vital point with these is to set the motor flush with the the bottom of the chassis, this improves the mesh no end.

Note that everybody had to use the same motor, so set-up was quite important !!.

My question was the derivation of a numerical "formula" claimed to be universal.

vbr Chris A.
 

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Hi

All nice but also you have to mention that car handling depends also on what type of car your drive

My Porsche 914 on PCS handles complete different than my Mercedes 300 SEL 6.8 AMG and both are top 2 cars BUT a pcs based car can never win against my TeamSlot Alfa modified with Slot it parts

Greetz Frank

It`s all about control
 
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