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April 19, 2011

+2mm Rear Roll Centre – DNX408

Filed under: News,Tricks and Tips — Tags: , — Stuart @ 3:01 pm
ttt-408-raisedpin-title
TTT-408-RaisedPin-bothinserts2

Raising the roll centre on the rear of the DNX408 is a modification some of our team drivers have been using recently to good effect and it’s a simple and cheap modification to implement using only Team Durango parts.

Pro Driver Billy Fischer says about the mod: “I feel that it gives the rear end of the car much more support for jumping and landing, as well as allowing the car to take the bumps better without bottoming out nearly as much.”

As standard the DNX408 can be built with 2 or 3 degrees of anti-squat and these settings are achieved with the various moulded inserts that push into the machined alloy hangers.  The rear-rear hanger inserts all currently use a central hole which is angled to match the off-set hole on the rear-front hanger inserts that set the anti-squat angle.

Using the RR 3/2 (rear inserts) and RF 3/2 (front) inserts on the back of the standard car gives 3 degrees of toe-in and 2 degrees of anti-squat.   To use this modification those are the inserts and angles you need to be running – the 3/3 items don’t have the same adjustment option.

TTT-408-RaisedPin-animationBefore and after – the +2mm Roll Centre mod.

To raise the inner hinge pin 2mm we need to raise up the rear-rear suspension hangers by that ammount as well as the front.  The rear hangers can be spaced up using the 2mm spacers from the DEX410 caster blocks – part number TD709004. You just need one packet of these since there’s 4 in the pack and that’s how many you’ll need.  Place the spacers under the rear-rear blocks and screw them down using longer 3×12 screws, part number TD704022 (the kit screws are 3x10mm).  You could use the kit-supplied 3x10mm screws but it’s sub-optimal and you risk damaging things since there’s less thread going into the blocks, you have been warned.

ttt-408-raisedpin-spacers1 The anodised spacers and longer 3 x 12mm cap head screws ready to attach the suspension hanger ttt-408-raisedpin-spacers2 Hanger attached and raised up 2mm.

To raise the leading end of the pin by the same ammount you can’t simply space up the rear-front hanger sine it’s trapped by the rear bulkhead but there’s an even simpler way – just swap the insers around so you’re using the right on the left, and left on the right.

ttt-408-raisedpin-insert1 The 3/2 rear-front insert has a low front pin hole ttt-408-raisedpin-insert2 Switching sides places the hole 2mm higher to match the rear-rear height

The inserts should then have the writing upside down – still using the 3/2 inserts. This raises the front end of the pin by 2mm to match the setting from the raised rear-rear hangers – keeping the 3/2 setting but raising the pin height and roll centre.

ttt-408-raisedpin-insertbrace Putting the left insert on the right and vice versa to raise the front end of the pin ttt-408-raisedpin-insertbrace2 The inserts should end up with the writing upside down
ttt-408-raisedpin-overview

With the +2mm rear raised roll centre mod complete you can expect the rear end to support itself more and have less roll in the corners – also helping the car over bumpy tracks and prevening it from bottoming out too easily.

150wideTTT

Parts required:

TD709004  – CASTER BLOCK SPACER 3x8x2.00mm (4pcs)

TD704022  – CAP HEAD HEX SCREW M3x12mm (10pcs)

December 29, 2011

TD330303 – ‘408 Toe-in and kick-up inserts

Filed under: News,Tricks and Tips — Tags: , , , , — Stuart @ 11:46 am
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The option part TD330303 ‘toe-in and kick-up inserts’ provide extra tuning options for the ‘408 series of vehicles.

When we talk about pivot blocks, we refer to them by two initial designations.  The first of these refers to which end of the car it belongs to – F for front and R for rear.  The second of the designations is the front or rear most of the blocks.  RF, for example means R – REAR of the car, F – front most facing of the rear hinge pin holders. FF means the FRONT block at the FRONT of the car.

fffrrfrr

The option inserts for the 408 provide extra options over the kit setup of the DNX408, DEX408 and DNX408T.  These control the front ‘kick up’, rear toe-angle and rear anti-squat.

kickuptitle_0

kickupinserts1_0 The front kick-up is the angle of the front of the chassis and the suspension follows this in kit setup with neutral inserts that add or subtract nothing from the chassis angle of 10degrees. The option inserts give the option to change the angle by up to 1 degree in either direction using just the FR block – or on the DEX408 and DNX408T the FF block can also be tuned using the same inserts to give double the range of adjustment.

kickupinserts2

More Kick-Up will tend to ride the bumps better and the steering response will be reduced slightly. The vehicle will tend to ‘dive’ more under braking.

Less Kick-Up will tend to ‘hop’ over bumps rather than absorb them, the steering response will be sharper and there will be less dive under braking.

Right: The kick-up inserts used in only the FR block

The kick-up inserts are left and right handed and are marked with a dimple to show which way round the setting should be read.

The dimple facing upwards means you’re offsetting the pin by the labeled figure, and with the dimple facing downward the setting is subtractive. When using these inserts in the FR block then raising the hinge pin would effectively reduce the kick-up angle and vice versa for lowering the pin.

kickupinserts4

The DEX408 and DNX408T use revised designs for their pivot blocks which allows the use of these offset inserts in the FF location also. Using the inserts on the FF block (only possible on the DEX408 and DEX408T) would give the opposite effect to on the FR block, and moving the pin up (+1) will add kick-up angle. Using the inserts in the FF location along with the FR location gives a greater range of adjustment to the settings – between 8 degrees and 12 degrees total kick-up angle.

It is possible to fit the DNX408T FF hinge pin block on the DNX408 – giving the ability to use the option ‘kick-up’ inserts in the FF brace as well as providing more strength.

kickupinserts3

The rear inserts are split between anti-squat inserts in the RF block – and toe-in inserts in the RR block.

antisquat-3x
antisquat-2 The RF block is used to set the rear anti-squat angle and all the kits come supplied with inserts to change anti-squat between 2 and 3 degrees.The option inserts allow a range of adjustment between 1 degree and 5 degrees total. These inserts come supplied in matching pairs – the 1-5 and 2-4 inserts can be run on either side of the car but the setting which is the correct way round to be read (the lower number) is the one that’s in use.

Anti-Squat Effects:
Under acceleration the rear of the vehicle has a tendancy to squat down and compress the suspension, as the weight shifts rearwards. Anti-Squat refers to the angle of the inner hinge pins which have a degree of incline, with the rear of the pin lower than the leading edeg. This angle helps resist compression of the suspension when on-power, and can help the car rotate in corners.

Running more anti-squat will give more on power acceleration at the cost of bump-handling and is more suited to smoother, faster and higher traction surfaces.

Less anti-squat helps rear traction and bump-handling ability on rough or loose tracks. The rear end will be more locked-in through corners.

antisquat-1

The possible settings with the standard roll-centre (RR blocks bolted direct to the chassis plate) is shown above and below. The example below shows the maximum possible anti-squat (5 degrees) using the shown insert – the red line shows the minimum anti-squat possible in this setup, which as explained in the illustration above, is 1 degree.

antisquat-4

When using the +2mm high roll centre mod you’re raising the rear hangers 2mm whilst the front stays in place.  As a consequence of this you need to raise the front of the hinge pin to keep a similar anti-squat setting.

What does it do?  Take a look at the article we put together on the mod here:  +2mm Rear Roll Centre

With the +2mm rear raised roll centre mod on your car, you can expect the rear end to support itself more and have less roll in the corners – also helping the car over bumpy tracks and prevening it from bottoming out too easily.

antisquat-6

The possible settings with the +2mm high roll centre mod are shown below. The example shows the maximum possible anti-squat possible (3 degrees) using the 5 degree insert shown below in the RF hanger.  The red line shows the minimum anti-squat using the 2 degree insert, which is ZERO.

antisquat-5 toe-inserts-3x
toe-inserts-1 The in-board toe settings are set by the insert in the RR block.  The original kit-supplied inserts only had a set 3 degrees of toe-in and this couldn’t be changed.  The option inserts give the ability to tune from 2.5 degrees all the way to 4 degrees of toe-in, in 0.5 degree steps.The four inserts supplied in the TD330303 optional inserts pack aren’t sided – meaning you can run them on either side of the car with the same effect. The number designations are embossed in both orientations to enable easier reading of the settings.
toe-inserts-2

TOE-In explanation and effects:
Toe-In refers to the angle of the wheels when viewed from directly above. On the rear of the car this is set by both optional hubs and in this instance by the inner hinge-pins via the inserts. The inserts included in the optional kit give the ability to tune from 2.5 to 4 degrees of inner toe-in and when using the 1 degree hubs this setting can be tuned an extra 1 degree in either direction if desired.

More toe-in at the rear will help stabilise the back of the car and keep it tracking straight. The car will have a tendancy to understeer and feel easier to drive on power. This is best suited to looser tracks.

Less toe-in at the read will be faster in a straight line as there will be less tyre scrub. The rear of the car will be looser and the car will turn more easily. This is best suited to higher grip tracks.

Your local Team Durango distributor
T: 217-398-3630
F: 217-398-1104
E: gpinfo@gpmd.com
W: www.gpmd.com
Great Planes Model Distributors
1608 Interstate Drive
Champaign,
IL 61822, USA
USA