DT-03 Suspension Setup

[skom25]

Hi,

Talking shortly, I am lost. What I have now:

- CVA shocks ( mounted on ball joints)

- Red and Blue tuning springs

- Front carbon shock tower

- Sway bars

- NiMh 3300 Battery

 

Current setup:

- Oil:

- Front: 400

- Rear: 800 ( was 1000)

 

- Sway bars: front soft/ rear hard

 

- Springs:

- Front Soft with medium spacer

- Rear Hard without spacers but with kit sleeve below collar to get rid of loose spring

 

- Front shocks mounted in middle hole on tower

 

- Both shocks mounted on inner holes of wishbones to increase height

 

I ran on gravel, hard sandy surface and on asphalt covered with sand.

There is a lot of understeer but I expected this and found way to reduce it. I have feeling that rear is little bit unstable. When front goes straight, rear is quite loose. I know that it is RWD with open diff but I think that it is something what can be improved.

What I observed is that rear suspension does not move too much. When I polished shafts they turned little bit orange. When they work on car, orange coat dissapears and turn silver again. Problem is that silver part is very narrow. Probably around 3 mm. I assume that suspension works the most on this part.

Any suggestions? I thought about soft spring on rear with 800 oil but afraid of hitting ground. SAG on both shocks is around 30/40% ( more or less).

How using different holes in shock tower will affect suspension? I believe it is not only matter of ride height.

Ignore text below:

BTW: I am little surprised with one thing. When I build model it had little SAG. When I put battery, it slowly lowered under weight. Now after 2h of dusty runs, there is no such effect. It does not move under weight. I have to push it down and then it will stay on SAG around 30/40%. Is this effect of sticky orings I read about?

[skom25]

1 hour ago, skom25 said:

BTW: I am little surprised with one thing. When I build model it had little SAG. When I put battery, it slowly lowered under weight. Now after 2h of dusty runs, there is no such effect. It does not move under weight. I have to push it down and then it will stay on SAG around 30/40%. Is this effect of sticky orings I read about?

Ignore this part. I forgot that during build I used outer holes in wishbones and then I switched to inner. It changed ride height and SAG a little.

I checked once again now and Orings are sticky but when I move suspension once, everything moves freely.

[BuggyDad]

I found that tackling understeer was my first priority with the DT-03. Caveat - I'm no racer, just a tinkerer, and I run mine on rough loose ground. But anyway I made my car better and most of the info was gathered here so it should be valid. To maximise front grip I applied a combination of:

- front tyres - I found mini spikes in a soft compound to be good but I haven't tested loads of different tyres. Big difference from kit tyres.

- adding weights to the front

- working on the front shocks to get them softer and more active, also not running a front sway bar (I ended up using no sway bars at all). Oil weight goes hand in hand with piston so will be different but with my (2 hole I think) pistons in alu shocks I use as light an oil as I can find (100). But I didn't go this light in CVAs. Downside - they bottom out very easily. On front shocks I might differ from what others have done so you might choose to ignore me, but it works for me! 

At the back I found @ThunderDragonCy's 3° toe in rear uprights (they're on shapeways) to make a huge difference in making it easier to keep straight and controlled under power. So much so that when I subsequently built a TT-02 budget rally thing I still spent money on toe in uprights even though I had little budget to spare. 

I also used heavy (500k) weight oil in the diff. The diff isn't sealed so I don't think you can rely on lighter weight oil staying in there. I also used a bit of gasket jointing compound to try to keep the oil in. Or you could use AW grease. My oil is far too heavy really but it doesn't leak and the car runs well enough. Ideally I think I'd replace the diff with a sealed gear one but I don't know of one that fits. 

[SlideWRX]

What type of piston in the CVA?  is it the completely metal one or are you running the plastic pistons?  how many holes?  400/800 oil is high to me.  It does depend on how much jumping you do and how high.  I think I an running 200/400 with 2 hole pistons (I think? been a while) but I don't do much jumping.  I'm ok with the chassis bottoming out occasionally.  Put some tape across the bottom of the chassis to see how much it gets scraped up after several runs.

What o-rings do you have in the CVA? black, red or something else?  black is sticky, red is a lot less sticky but still a litlle bit, and others (clear or blue from Tamiya I think)are even less sticky, but might not show much different with basic un-coated steel shafts.

If an orange color gets onto the shafts, but comes off after running, it is getting worn off like the original coating.  It gets applied when you polish.  Is the shaft stickier with or without the orange? Maybe you should polish them a lot

[skom25]

1. Steel piston without holes

2. Black Orings

3. I polished them and turned orange. There is no difference between colours.

 

[skom25]

19 hours ago, SlideWRX said:

It does depend on how much jumping you do and how high. 

None. I run mainly gravel/ hard surface/ asphalt.

I do not have lighter oils than 400 for now but I can order. Do you suggest to go for 400 on rear? Will not it be too bouncy?

 

[skom25]

I installed turnbuckles this week.

Since I want to go only On-Road, I do not see reason to have so much ride height as now. I do not see any chance to lower front but what about rear? Maybe short eyelets?

Any ideas how to adjust it more to hard surface conditions?

[alvinlwh]

35 minutes ago, skom25 said:

I do not see any chance to lower front but what about rear?

Sorter eyelets and/or spacers inside the cylinder. X3, 4 and 5 if I remembered the numbers correctly.

[skom25]

Adjustable turnbuckles really improved handling. I am surprised how different it is now.

I still have feeling that rear is too stiff. Is it worth to try soft spring?

In my theory:

- Without throttle front will have more grip because of balance moved to front. Rear will be less stable

- Rear will be unstable on braking, because of much balance on front

- Rear will have more grip during acceleration

Am I correct? What about cornering with soft rear?

I found that front wheels "vibrate" during hard turns. Should I add more negative camber or decrease it?

I am also not sure, what to do to increase rotation. I have feeling that rear is little lazy during Turn In.

[Twinfan]

I run Hop-Up hard rear springs, Hop-Up soft front springs, negative camber at both the front and rear (more at the front than the rear) and toe-out at the front.  All this, except for the springs, is based on my experiences with my 1:1 car and it works well on the very long DT-03 chassis in my opinion.

The rear needs hard springs to combat the weight of the motor and gearbox, the front needs to be soft to allow weight transfer when braking.