HPI Trophy Truggy and Buggy Owners Club!

[Dan201]

It sounded like a daft question but from the little I know the power in a car is sent to where the least resistence is. So if the oil at the rear is half as thick as the rest then thats where it would be sent. Same ratio as 100k - 50k.

[BlackFlash]

Locking or slipping diff - i'ts very depends on track ground... I usually use 10/10/2 viscosity in my Truggy.

[Rusty1103]

I wouldn't lock the centre diff up purely for the reason of in air handling, hitting the throttle in air with a locked centre diff will make the car rotate on the centre axis, with a diff that's not locked ( like Chris said) the power will go to the wheels with least resistance in my case the rear. It is easier to land jumps because rotating on the rear axis will give more leverage. A small blip on the throttle will make a larger effect on the angle that the car is to the ground.

@deafty

Are you referring to cst or wt when talking about your oils?

[CalumR]

I suggest we put a poll on what to use either CST or Weight, that way every one knows what we talking about. most of the time when people are talking oils it is done in weight, but I have seen alot of manufactures put CST on the bottle. is CST and weight the same or different, and if so how do you convert weight into CST???? OMG why are diff oils not standardised!

I am using F100wt M50wt R30wt

Edited September 27, 2012 by CalumR

[Rusty1103]

That's the thin tho, different brands have different conversions/viscocity. I was looking at tables last night. Here is a couple

Losi silicone oil measured with Rheometer

15-12-2005

rating cSt

15 110

17.5 158

20 243

22.5 243

25 294

27.5 345

30 381

32.5 397

35 459

37.5 477

40 546

45 657

50 886

60 844

70 970

Associated silicone oil measured with Rheometer

09-10-2005

rating WT on bottle cSt cSt*

10 108 100

15 --* 150

20 208 200

25 286 275

30 373 350

35 454 425

40 525 500

45 - 575

50 707 650

55 - 725

60 725 800

70 960 900

80 1040 1000

Here is the link to the page with a lot more tables. http://www.rcrcr.com/index.php?option=com_content&view=article&id=56:shock-oil-cps-vs-wt&catid=31:general&Itemid=46

[ShadowDEMON88]

This is not helping.... Just getting worse!!

Someone correct me if I'm wrong

WT is a rounded up weight where as CST is more accurate but the numbers are still in there thousands

As I'm a basher and not a racer it doesn't have to be so accurate I just want to set up my car properly!! The problem is I can't find the oil weights I want and thought as the set up was suggested on here people would actually know where they got there oil from.... 70k 50k 30k Got the 50k but 70k is hard to get hold of if it actually exists

[CalumR]

this is the 30K I used

http://www.modelsport.co.uk/traxxas-differential-oil-30k-weight-/rc-car-products/20153

the 50k

http://www.modelsport.co.uk/traxxas-differential-oil-50k-weight-/rc-car-products/23849

as for the 70k I couldnt find any either, so i used 100k

http://www.modelsport.co.uk/traxxas-differential-oil-100k-weight/rc-car-products/32957

A little tip, put the pottle in to some warm water, this will help the oil flow better.

[Dan201]

When switching diff oil is it ok to take apart the dif and get rid of most of the oil but not bother cleaning it?

[Deafty]

@deafty

Are you referring to cst or wt when talking about your oils?

I'm using these diff oils by Ansmann . All a bit confusing really. Perhaps I'm even using the wrong ones:

My 70 is "Silicone differential oil 70000 CPS"

My 50 is "Silicone differential oil 50000 CPS"

My 30 is "Silicone differential oil 30000 CPS"

Which I now find is different still!

Here is a converter from CPS-WTand vice versa.

Also here is some helpful understanding on the subject.

From what I have read, different manufactures can not be compared to each other.

Wt such as automotive 30/40 is the viscosity at 2 given operational temperatures temp A is 30 and temp B is 40 Often A is at 0

Edited September 27, 2012 by Deafty

[Dan201]

According to that converter my 10k wt centre is far thicker than your 70000 CPS centre.

[Deafty]

Yeah comes in at twice as thick,..

[neutron2k]

Just got these little beauties through the post from HPI Racing. Designed for the Lightning Pro 2 EVO but are compatible with my buggy flux, and as they were reduced to around

[Rusty1103]

i will post what i have in my trugy tonight, with the results of the handling

[Dan201]

Yeah comes in at twice as thick,..

To be honest im totally lost about which thickness we all have now. Before you said you wouldn't go below 20000 but now it looks like 10000 wt is much thicker than yours.

[ShadowDEMON88]

Cheers CalumR for that info. Tho think 100k is a little to high gonna go for the 75k wt

This has to be one of the most confusing things in the rc world. Makes tuning a nitro engine a piece of ****!!??

[Deafty]

To be honest im totally lost about which thickness we all have now. Before you said you wouldn't go below 20000 but now it looks like 10000 wt is much thicker than yours.

That was with the oils I use lol,. and by what happened to one of my diffs, I stand by what I said,.But again CONFUSING

There is one accurate way to measure viscosity, and that is with a "din" cup. It is effectively a small funnel. Your pour n your set amount of liquid and the time it takes to empty is "dins/per second. I have used these before when spray painting.

If I can find find I'll measure my oils,. and perhaps when I'm at the track next time I ask if Ican start pouring other peoples oils,.

Seems like the only way lol.

[rob12]

I spoke to motorsport and for the truggy flux they recommended 7000wt front 10000wt middle and 5000 wt rear that's using fastrax diff oil. I used this on second run drive has gone lol so going to open up see what's what

[CalumR]

Come on there has to be someone here doing fluid dynamics/viscosity at university, who can help?

[ShadowDEMON88]

Are we not all missing the point here. No need to check the viscosity of diff oil just a simple guide on using the right units in regards to whats available on the market and what everyone else is using.......

[Dan201]

Has anyone replaced the ESC? Im wondering if upgrading to a 120a esc will make much of a difference.

The Hobbywing ezrun WP SC8 looks good for the price. What else would need to be changed to make the car waterproof?

[Rusty1103]

Right my diff set up is all ansmann racing silicone diff oil and the weights are 7000 cps front 5000 cps middle and 3000 cps at the back. I run on ash at a BMX track and short grass. The light oil in the rear is superb fun as I can easily kick the back end out but it is still unbelievably controllable. On the grass because there is more grip the front digs in and I can just point and shoot the car where I want it to go and it goes there

[neutron2k]

Has anyone replaced the ESC? Im wondering if upgrading to a 120a esc will make much of a difference.

The Hobbywing ezrun WP SC8 looks good for the price. What else would need to be changed to make the car waterproof?

I've upgraded my Trophy Buggy Flux to the XeRung 150a ESC and 2200kv motor with 44t spur + 19t pinion on 5s. It FLIES.

[Dan201]

I bet it does!

This combo looks good

http://www.ebay.co.uk/itm/XERUN-Sensored-4068SD-2250KV-Motor-150A-ESC-LCD-Program-Card-/251070920691?pt=UK_ToysGames_RadioControlled_JN&hash=item3a74fe37f3

Im just window shopping at the moment, I dont need to buy anything. Would a 4s 5000mAh 40c battery be enough for a combo like that?

[neutron2k]

Yeah 4s is fine on the XeRuns You'll need a deans loop adapter though if your only running a single 4s battery and not 2x2s.

[Deafty]

Right my diff set up is all ansmann racing silicone diff oil and the weights are 7000 cps front 5000 cps middle and 3000 cps at the back. I run on ash at a BMX track and short grass. The light oil in the rear is superb fun as I can easily kick the back end out but it is still unbelievably controllable. On the grass because there is more grip the front digs in and I can just point and shoot the car where I want it to go and it goes there

Thanks for posting Rusty.

Interesting, I'm running mine (same ansmann) but at ~10x higher 75,000cps front 50,000cps mid + 30,000cps rear

and although that maybe read as 1/2 the values @wt we dont know the temp for those figures.

Run on Very dusty dirt tracks: Can spin out easily (though crap tyres) power down for immediate jump not so good. 4 wheel drift cornering under power is easy to control. Out of corner good. Under brakes, good but not great. On tarmac, runs glued to track. Grass , point and shoot, Airbourne, slightly slugish but comortable nose up, faster nose down.

+++

On another note I'm going ahead with an engine rebuild after ~35 Litres, just awaiting a small engine crankcase delivery (screw holes are threaded on my current one and it's going to be easier and quicker to replace that part,.. until I get it the original one repaired)

+++

Sorry cant offer help to u flux fellas,. aint got one so its better not to comment.

Edited September 27, 2012 by Deafty