I have 8 of these GT-40's... all but two of them are Slot-It.. the other two are Scalextric - and they "stink"... they run, but they are more of a "kids" slot car.. they have no performance and slide around on pretty looking tyres, which do almost nothing to either give them traction, or any cornering ability.
The motors run hot and I spent (wasted) way too much time working on them.. the end result wasn't a great improvement to the overall model...
One thing which I do with Slot-It chassis'.. is to "relearn" the plastic... this is achieved by filing/scraping/cajoling anything "proud" on the underside of the chassis.. so that it will "lay flat" on a sheet of steel plate.... we lose a bit of detail and some of the manufacturer stamping.. but, for a good cause.
The chassis is then pushed down with a lot of force onto the steel plate by the fitting of rare earth magnets (hence the steel plate) at locations where there is any "buckling" or high spots..... when we are happy, we immerse it in as close to boiling water as can be safely and slowly poured over it until it is covered by about 2" of water..... this destroys the previous memory of the plastic as it was allowed to cool down from being poured at the factory - they simply don't have the time to do the same process we do.. these models are produced in their thousands... QC at Slot It is very good - but they are not looking for anything other than obvious defects... voids and obvious buckles, missing parts from frets etc. etc...
We then cover over the bath with many towels etc.. to hold the temperature for as long as possible.. 12 hours is a good period for the water (and chassis) to cool out...
What happens in this time, is the slow cooling process allows the plastic of the chassis to learn a new memory... and, when we remove the magnets - we hope that it is now laying absolutely flat on the set up plate.... now, we have a "flat" chassis... where all axle mounts should be in an equal plane.... or at least - equal across each axle mount.... the chassis is also now "true".. and we can go to work on setting up our measurements...
I'm not going any further with this for now... but, I believed it important to reveal that it's really the chassis which determines how well the car can be set up... if the chassis was distorted or had a memory which did not flex in a uniform manner - we'd never get it to stay within those tolerances in running... no matter how much effort we put into the next stages of preparation....
I'll jump ahead to suspension now... we'll do the rear first.
What you can see in this pic, is the dual spring arrangement that is an additional tuning option with most of the Slot It cars..
The aim is to incorporate the ability of the rear axle to move vertically, but not laterally or longitudinally... we only want it to go up and down.
To do this, we must make the "pod" move as well.. and, with the motor firmly locked to the rear axle - it has to move up and down as well.
We fit springs on both sides of the axle... and allow some "riding" out of uneven track.... so, we sort of have "independent" rear suspension... not fully - but the axle can not only move up and down, but it can also move up and down at an angle...
I'm going to shock you when I state that this movement is only 1.5 mm from fully up to fully down.. but, the difference it makes to performance is simply astounding on plastic track... which is terrible for use as a level or even plane....
I'll shock you even further and tell you that on competition circuits and club tracks - suspension usually makes not one jot of difference... duh?
These tracks are made without any imperfection.. they may as well have been made with glass and covered with a textured paint... they are almost perfect.... usually made of wood and the guide slots routed out in three passes.. one deep, for the guide and two others into which continuous lengths of copper braid are laid down for contact... there is a slight recess from the track height down to where the braid is.. so that it is not unduly worn by tyres.. but not so much as to have those tyres "drop" into it ...... routed tracks do not make any noise as the models runs on it... no "clack, clack, clack" as the guide passes over joints between sections.. they are truly delightful to run on... and virtually any layout can be constructed.. with overpasses, tight curves, humps, spirals... it is only restricted by the designer's imagination.. I have driven on some amazing circuits... with added scenery and spectators you can almost hear cheering...
Ok back to suspension....
Pic..
- 008 Godzilla rear susp mail.jpg (143.15 KiB) Viewed 841 times
Ok - that motor... it has 280 gm/cm of torque.. the resistance of the magnets is huge.... when braking is effected, those magnets draw so heavily on the armature rotor that it loses speed very quickly... add to this, the electronic braking that modern controllers afford... the motor literally "snarls" when heavy braking is applied...
With Godzilla - we go even further.. that great gear reduction.... starting to get the picture... it is undriveable without a programmable controller.. the chaps at the slot car group hated this car.. it really showed each of them up for what their natural talent lacked..... none of them enjoyed driving it...... but, when I dialled in my settings to what I had learned... it "de-fanged" the beast... without greatly taking away much of the available power or braking... it had to be "electronically" choked... so that it couldn't "launch"...
In the next pic, we see the motor and the gear reduction.
This arrangement is called a "sidewinder"... as opposed to what I posted with the little Cooper.
The direct alignment of driving a pinion into a spur gear without any 90 degree matching affords more direct mechanical stability and contact. Wear reduction is another great advantage... with the axle shimmed in place - the pinion will run forever in exactly the same line on the spur and vice-versa..
- 009 Godzilla driveline mail.jpg (149.94 KiB) Viewed 841 times
Ok - close up pic of the rear suspension adjustments.... you can see the two main coil springs.. one for each side. Adjustment for these is made using four screws.... two of them are clearly visible.. the brass ones... there are a further two minute Allen key screws which adjust the opposite end of deflection... it is between these two adjustments that we can set the travel of the axle.... with this model, 1.5 mm has been the best setting.
We can also change the springs for a different compression .. these are the stiffest available in the range... to withstand that torque and gearing... using any softer springs negates the suspension entirely under power.... it simply compresses as soon as power is applied.. and until speed reaches a "coast"...
- 010 Godzilla rear susp adj mail.jpg (141.36 KiB) Viewed 841 times
Ok - front... it has adjustment as well.. we need to be able to set the height of each end of the front axle as well.... there are tracks which have very tight curves on inclines..... with these, I set the axle up by 1/4 turn of the Allen screw on each side... it's not much in the grand scheme of things... probably 0.25 of a mm on each side.. but, it makes a difference as to the speed that the model will go around a tight corner.. if left absolutely flat - the outer tyre can cause the inner rear to lift.... and we get unequal weight across the rear axle.. the outer rear tyre will then "bite" into the track and topple the car over.... keeping both rear tyres on the track allows the rear end to give indication in "drift" that it is about to let go...
front axle adjustment screws....again, one brass and one Allen each side.
- 011 Godzilla front susp mail.jpg (136.24 KiB) Viewed 841 times
Ok, that should do it... I can go into a lot more detail and will do so if there is any interest.... but, for now - I've probably gone way too far already.
Next, to show you the detail these Slot-It cars come with - take a peek through the beautiful studded side window at the dash, console and general cabin layout.... this is really up there with the best of what is available in retail.... they are a beautiful model - and this GT-40 is probably one of my favorite models from that company... it must be - I have six of them...
- 012 Godzilla dash mail.jpg (141.25 KiB) Viewed 841 times
Ok - this is also another great feature the company adds... the mounting of the model in its jewel case.
I have been doing this for years..... people ask me what my adding "icy pole" sticks to my storage cases is for... and I tell them - to keep the model up off the floor of the case... specifically - the tyres and wheels.... tyres get a "flat spot" in them if the model is screwed down onto the base and left there for more than a few hours... these flat spots are identical to having locked up a brake in 1:1 competition.. your times simply go out the window as the tyre makes and breaks contact with the track...
We can see in the pic below, that the model is locked into position up on a raised section - the tyres are well clear of the base...
- 013 Godzilla case mount mail.jpg (210.94 KiB) Viewed 841 times
And, to bring this to a close - the rear of my box... I put little labels on things to tell me what has been done and when it was done.
I simply can't remember what has been done to all my models... there are probably 40 of them now, with another two about to be added... the Torries...
In this pic, we can see that I have "tuned" or modified this model twice now from when I first built it... we've done a bit of work with suspension - it suggests that there has been an issue with the rear right having dropped and that "float" has been included in the axle shims.... sometimes, in a long race - the axle will heat up and bind... we set shims so finely (down to 0.2 mm) that this clearance can be removed due to heating up of the axle i running... remembering that this model has a lot of power to tap into... and it is both in powering and braking ..... the axle has been re-shimmed to allow a little more float at running temperature... we also see that the last tune-up was just short of 2 years back... possibly, the last time this car was used...
- 014 Godzilla note mail.jpg (177.74 KiB) Viewed 841 times
With so many, and I love them all.... I usually only pull down a dozen or so from the vault for any given event weekend... I never put them back into storage without a full inspection and cleaning out of the oil and braid.... and a light re-oil (Inox MX-3.. think I mentioned that?)... then tucked away back in their jewel cases and sent back into storage...
Ok - guess that's it for a while now - until my parts come down from Armchair...
If anyone want to look at anything in particular - or a particular model - bang up a post here and I'll oblige....
frats,
Rosco
