banx

hi. have any of you guys tried boiling some of the plastic parts on your buggies? i have a hpi nitro mt as well and on some boards like this they say to boil a arms to give them added strength. i'm just wondering oif any of you have?

when i get my new front knuckles i am going to boil them and see if they last longer.

i like this buggy but it nvere runs more than 5 minutes without breaking. i mean i havent even fully tuned the engine yet without the thing running out of the *****ty radios range and crashing into something. hahaha

Ryan11

O_o wouldn't think that would strengthen them, you could give it a go. My smartech runs fine, I played with it too much and melted the clutch.

J_D

boiling plastic.. might make is "stronger" ie. harder... also means its more brittle and will snap easier? ... I think?

banx

well i didnt bother boiling the knuckles. I did however install better radio gear. wow what a difference. it didnt run away on me and crash once. and the car is in one piece.

have you guys tried making any home made any homemade hop ups for these buggies? i'm going to try crafting some shock towers out of aluminum. i did put some all terrain tires and rims from my HPI MT, they fit perfectly and give the buggie some ground clearance.

Ryan11

me broke my buggy [:'(] i was bombing round and I smashed into a curb. Damage:

# Snaped front wishbone
# Bent wishbone pins
# Snaped front cross bar thing

So ive ordered them and a new clutch aswell. So buggy should be running by next week

Ryan11

o, and ive bent a suspension unit aswell

andyb178

Hi Ryan
Did you get a reply from that guy advertising smartech parts on ebay? he told me he would send me a message over the weekend, but hasnt []
So my car is still off the road at the momment (no gearbox)

chocyman

Ryan...

Unlucky mate, its a pain in the ***** when it breaks and breaks properly isnt it? Still, least you didnt bend your chassis or smash the fuel tank...it gets messy and expensive when that happens, trust me!
Excelhobby or Raidentech and get the parts you need and you`ll be up and running in no time.

By the way, think its pretty easy to convert 2 speed to single, and vice versa (if you can find a 2 speed g/box for a reasonable price). Ive stuck with the single speed as it means more choice of spares and off the shelf stuff instead of having to use Smartech parts. Think its just a case of buying the single speed main gear and a clutch gear to suit and then fitting it.

andyb178

what sort of speed do you get from the single speed? my 2 speed would hit over 40mph ( should do 50mph + but i dont think it ever will), might be a good idea to go for the single speed though

chocyman

God knows what speed i get....Its a tricky one to judge as im really not after speed. Ive mentioned in previous posts that if id wanted a balls out fast buggy, Id have gone for a Hyper or something with a .21 engine in.
Saying that, ive got a .18 OS engine in it, plus geared it up to give slightly better top speed without sacrificing lower end grunt. Cant say a bad thing about the OS as its pretty powerful and 100 times easier to tune and keep running than the standard Smartech motor/carbie.
Think the standard single speed clutch gear is 15T, so ive gone to a 17T and stuck with the standard main gear (no idea how many teeth that has). It will wheely quite happily all the way from standstill till it gets going, then goes pretty well in a straight line..even corners fairly well given the better shocks (Duratrax).
Saying that, a well tuned and setup 2 speed is going to be faster no question. Its just the damn spares problem again if they strip/break[:@]

chocyman

Just been reading the post here :- http://www.rcuniverse.com/forum/m_2146373/tm.htm on gear ratios.
Think it would be good to work out what the buggy should be and therefore what the 'theoretical' top speed should be.
So..can anyone help with an internal gear ratio??
I.E if you turn the diff input shaft 1 revolution, how many times do the output shafts turn??
From the post above, seems that a typical value is approx 2.5, but maybe different for buggies.
Or if anyone has their buggy and diffs apart, if they can count teeth on the diff input bevel gear and main diff gear, its a simple bit of maths to work out internal ratio.

From there if we measure the rolling diameter of the tyres, work out theoretical max RPM of your engine, then punch the numbers in and work out distance travelled, and therefore theoretical top speed (wont take into consideration friction (wind,heat,moving parts) and other factors (motor not reaching top RPM etc)).

Anyone have theirs apart to count the teeth?
Post them here if you can.

**EDIT**..just found the winner sport is (hi ratio) 8.24:1 and the wheel diameter of 88(mm?)

OK..here goes. Im assuming the 8.24:1 is including the clutch gear, so assuming the engines rotates 8.24 times to turn the output shafts once.
i`ll use the figures from the OS manual for my engine as a rough guide. My CV-RX produces 1.35HP @ 28,000 rpm.

So..28000 rpm/8.24 ratio= 3398.058 rotations of the output shafts per min

Wheel diamter is 88mm, therfore rolling circumference is Pi X diameter:- 3.142 X 8.8 (cm) = 27.65cm travelled per wheel rotation.

Ok..getting there.

So if we are producing 28000 rpm from the engine, we turn the wheels 3398.058 times per minute, which travel 27.65cm per revolution

So, in 3398.058 revs, we travel 3398.058 X 27.65cm=93956.3037cm per minute OR 93956.3037/100 = 939.56 meters per minute

Finally...we need to work out how far we travel in 60 minutes (Kilometers per hour).

So, 939.56 meters per minute X 60 minutes = 56373.78 meters per hour OR 56373.78/1000 (1000cm in 1 Kilometer) = 56.373 Kilometers per hour.

If you want Miles per hour, then multiply this value by 0.6214, so 56.373 X 0.6214 = 35.03 Mph

Thats a best case judgement (based on a 0.18 CV-RX Os engine and a 2 speed Winner sport) with no resistance or outside factors taken into account.

Bit surprising really, as I thought it would be faster, but puts a few rumours to rest.

Naturally if you can get more RPM or a better ratio out of your car, then this value will change.

**ANOTHER EDIT**

Apparently the ratio of the single speed is 8.4:1

Using the above info, this makes the theoretical top speed of the single speed to be 55.3 Kilometers per Hour or 34.36 Mph

J_D

all that blah blah blah.. lol.. which is just theoretical..

Just get a VSM

chocyman

Whats a VSM?? some sort of speed monitoring device?

Yeah I know..lot of yardahyardahyar, but should stop people coming out with "my car does 100kph and its standard" sort of BS.
Its not 100% theoretical, its just it doesnt take into account other factors. In an ideal world if we had no friction or forces of nature working against us this would be the top speed of the car. The calculations are based on fixed constants (like gear ratios) which do not change.

Just thought it was interesting to see the absolute top speed of the cars out of the box and interesting to see a single is only a few Kph below a 2 speed.

J_D

its a little device that goes on ur car, and measures ur top speed... also has an odometer, so you can see how far you travelled, and also a lifetime odometer, so u can see how many miles ur car has done in its life... and has an in built voltmeter, so you can check ur reciever batts before u start her up

have a look at www.venom-racing.com for venom speed meter

They arn;t deadly accurate like a radar, because if you wheels are spinning, it will tell you how fast they were spinning, as apposed to how fast u were actually going, but they do give a good indication

Ryan11

Nope, but i think i have to send him a message first for what i want to buy off him

And what was with all the giberish! lol, Buy a Rolling road / dyno. If you dont know what 1 of these are, here you go: [link=http://www.rcdynosystems.com/]rcdynosystems[/link] But the problem is that.... IT COSTS $1295.00!!! :S So my mate is making 1 for his electronics project ^_^

Jay-r

Ryan or anybody, When I was running my car today it stalls everytime I hit full throttle and dies when I hit the breaks. Why is it doing that? And also sometimes it does not die when I hit full throttle but after running it for about 4 minutes even though it still has fuel in it, it then stalls again.

J_D

if it stalls when u brake, either ur clutch is screwed, or your idle is too low

chocyman

If it stalls at full throttle, theres a fair chance its too lean. Richen the HSN up a little. If it stalls at idle/brake, then theres a fair chance as JD says, the idle gap is not enough.

Hope it helps

Jay-r

Chocy what is the idlegap?

Jay-r

Thanks JD and Chocy, I'll try it.

chocyman

1mm - 1.5mm. Its more a listen and adjust type thing anyway, make sure the idle is not too low otherwise it will stall often, and make sure its not too high as this can cause the clutch to burn out.

Jay-r

Thanks Chocy, I'll try it next weekend.

Ryan11

my buggy is still out of action. I ordered some bits bout 9 days and they still havnt come, i hope they come today, Last time i ordered parts from www.excelhobby.com they came in 6days :-/

J_D

did u get a confirmation email yet?

Mine took 7 days

Ryan11

well i dont get confirmation emails, my dad does so ill check now.