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Old 04-11-2007, 11:21 AM   #13846
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Quote:
Originally Posted by minnesh
ok guys
this is it
i have had enough
loosened the belt
clearned all the bearings
fully charged a 4.2 battery
changed pinion to 38, 34, then back to 41,,,,,,, (oh spur is a 86 tooth)
and stll a ttoi (10 year old son) was on my back all the way
i dont under stand

the two cars have the same 540 motor( I even swapped the motor when the kid was gone for some food, that did not work...)
(very bad dad)
am i just wasting my time with a losi xxx s in a 540 motor class.......
however i have purchased a spur gear adaptor which is on the way (maybe if this will help at all i must say i really dont know now ....)
help.., help.., help.., help.., help.., help., sos., sos,.sos,.a
a newbie is distress help here.....

now can any of the losi gurus help me out here
do i just need to move to modified with a brushless
or what do i do here
sorry for the long post
thanks
mnnesh

The 540 class besides having a very good motor is all about smooth driving and corner speed. Try using a front one-way diff and take out the drag brake on your radio. You also want your final drive around 4.70 to 4.50. Also batteries you need some real good batteries to be competitive in this class.
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Old 04-11-2007, 12:42 PM   #13847
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Quote:
Originally Posted by team green
The 540 class besides having a very good motor is all about smooth driving and corner speed. Try using a front one-way diff and take out the drag brake on your radio. You also want your final drive around 4.70 to 4.50. Also batteries you need some real good batteries to be competitive in this class.
thank u
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Old 04-11-2007, 12:44 PM   #13848
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Quote:
Originally Posted by DNOS
Blin,

I run a little bit tighter diff in the front(assuming you're running on carpet) That gives me more on power steering. If you want more off power steering, you need to run your diff as loose as you can without causing the drive gears to slip. I run a 13.5 brushless in the stock class(brushed and brushless together) with the sintered rotor, so it has so much more torque that I have to run my diffs a little stiffer.

Minnesh,

You need to check and make sure that everything run smooth when the car is ready to put on the track. Check and make sure your diffs are smooth and make sure your wheels turn freely with no stutter when you turn them by hand. If you tighten your wheels to tight, the car will run slower.
thank u
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Old 04-11-2007, 12:47 PM   #13849
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Quote:
Originally Posted by koinonas
Minnesh, dont give up on XXX-S yet. Its an old design, but its still more than adequate for 540 ad dare I say stock club racing as well.

Interesting how your comparing it with your sons TT01. I've got both and at the start found that the TT01 accelerated much faster, virtually no difference in top speed, but Losi had much better control and handling. However since sorting out a few things with suspension and drivetrain, have found that Losi is much better in terms of both speed and handling. In fact, I find the TT01 really slow and hard to drive now compared to the Losi....

But its actually good to hear that you've got both as you've got something to compare with. I still think that something's too tight in your drivetrain. So pull the motor out of both, and give them both a little push and see how far they roll. If the TT01 rolls a lot further than the Losi, then you've got something too tight in the Losi drive train. If they both roll a similar distance check that you haven't got your diffs and belts aren't too loose (you may be loosing a lot of speed if one or both are slippin).
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Old 04-11-2007, 01:09 PM   #13850
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Quote:
Originally Posted by LOSI123
if you swaped the motor and are sure its not the motor,

then it must be something you are over looking / have not relised.

are you running standard 63mm rubber tyres (diameter)

is it a tight or open large track?

have you double checked the end points on the controller then re set the esc setup?

have you tried the battery out of the tt01?

is the car or body scraping on the track?

what is the total rollout?

are the diffs too lose and slipping?

have you pulled out the motor & tryed the roll test to see if the car drive line is stiff or binding at all?


I will be able to work it out as my xxx-s is one of the fastest in 540 and i have been to heaps of clubs/tracks with very fast / experienced drivers that run high end cars, & my xxx-s is still up there with the fastest.

ok if i understand this
my existing roll out is 5.76 wiith
tire diameter 69mm
spur 86
pinion 41

need to change tp 34 pinion to get + - 4.6 roll out
is this correct
thanks
minnesh
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Old 04-11-2007, 05:03 PM   #13851
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Can i just say, before u try anything else, i have been running stock for awhile at my club and i also run a 86 spur, just try a lower pinion such as a 25. Just try a 25 once to see if that does it.
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Old 04-11-2007, 06:09 PM   #13852
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minnesh:

you are talking final ratio's


rollout is the way to go when talking gearing as it takes into account tyre diameter, other wise getting "joe blow's" opinion on ratios could very well be totally wrong for your car as "joe blow" may have foam tyres at like 58mm or something or you are running foams and "joe blow" is running rubbers.


go to http://www.gearchart.com/index.cfm?f...n=chart.create

put in your car (its under losi xxx-s)

put in your teeth on spur & pinion also put in your tyre diameter in milimeters
(most rubber tyres are 62 to 63mm)

then click on rollout! (not gear ratio)

it will plot out a chart, print this out as it will show you what your rollout will be with a fair few different pinions smaller & larger.


Rollout is the amount the car will travell per one revolution of your motor.


please tell me what track you run on & what exact 540 motor you run (johnson chrome or grey can etc..)

& what exact tyre type & diameter / (brand if running rubber)

This problem you have can be sorted it just takes time, effort, & sometimes some money, lol
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Old 04-11-2007, 06:13 PM   #13853
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Quote:
Originally Posted by rcstunt101
Can i just say, before u try anything else, i have been running stock for awhile at my club and i also run a 86 spur, just try a lower pinion such as a 25. Just try a 25 once to see if that does it.
Dude he is running 540, which is totally way different in terms of ratios or rollout compared to stock which you are running.


if he put the gearing to what you are saying he will want to throw the car in the bin it will be so slow.
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Old 04-11-2007, 06:44 PM   #13854
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If you want to do from first principles (note the 1.83 only works for XXX-S)

FDR = Spur/pinion x 1.83
Rollout = 3.14159 x tyre diameter / FDR

So using Minnesh's current gearing we get
FDR=86/41x1.83 = 3.84
Rollout=3.14159x69/3.84= 56.47mm

My gut feel is that the 540 motors can really only go down to FDR's in the low 4's or rollouts up to the mid to high 40's. Once you go beyond this your working the motor too hard (not enough torque to get accleration or wind up to top speed). My guess is that your motors also coming off very hot after a few minutes?

If you drop down to the 34 pinion I think you'll get much better performance. (FDR=4.63, Rollout=46.8). However I also want to check what type of tyres your running. Most of the tyres I've seen are all around 61-65mm diameter.

So suggest you double check that drivetrain is reasonably free, drop down to 34t pinion and do another comparitive run with the TT01.

Last edited by koinonas; 04-12-2007 at 04:10 PM.
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Old 04-11-2007, 08:47 PM   #13855
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Anyone looking for a spare or two XXX-S cars? I have 1 XXX-S G-Plus and 1 XXX-S Basic that I am thinking of putting on ebay.
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Old 04-12-2007, 11:24 AM   #13856
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thank u
ok the tires are nitro shoes 59mm foams
motor chrome can with black end bell
i have been to a hobby shop + - 100 km away and was told thatafter the stri[pped the diffs
1. it was to dry so he put some losi lube and fitted it althouhg i think he really tightned it....,,,, but he says thats the way to do it ,,,, he is the prof
so i am not going to question that
the way he did itis if u hold the one wheel and try and turn the opposite one it bearly turns with holding all other wheels not to spin
car does feel better however did not have radio and stuff to test
i am going to race it this weekend
and will see what happens what do u guys think maybe this car will be a good car only for stock and mod
once again i must take the time to thank each and every one who has helped me .
i really appreciate it
thank u
minnesh
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Old 04-12-2007, 06:09 PM   #13857
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Hi Minnesh,
The XXXS is great for 540, I got 2nd in the state with it running in the 540 class, agaisnt FT TC4, T2, 415, Mi2, TC3's, etc. With the diffs if you are running balldiffs front and back i would run the front one fairly tight and have the rear one loose enough so the diff doesnt slip.

With the gearing i ran a final drive ratio of 4.28 with the 540 motor. It did get really really hot but, my pinion was 32 and my spur was 75(i had the gear adaptor) and i was running standard height rubber tyres. In your case i would run the 38 pinion on the 86 spur which would give a final drive ration of 4.14 (i have run down to 4.11)

To see if your drivetrain is free, just take the motor out or the pinion off and push it along the ground, it should roll for a while with a good push, if it slows down all of a sudden there is something binding in the drivetrain or somethings to tight.

Also you say that your son is on your back the whole race with his TT-01, could he just be a really good driver? (Sorry if that might have sounded like a stupid question)
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Old 04-13-2007, 04:40 AM   #13858
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fast xxxs hello
my son is not so good but i must say that we have about the same amount of racing time behind the both of us
i will try this gearing this weekend
i have also ordered a spur adaptor as well
so... i must say that things are looking better
thank u
minnesh
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Old 04-13-2007, 07:36 AM   #13859
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Quote:
Originally Posted by minnesh
fast xxxs hello
my son is not so good but i must say that we have about the same amount of racing time behind the both of us
i will try this gearing this weekend
i have also ordered a spur adaptor as well
so... i must say that things are looking better
thank u
minnesh

hey where did you order the spur gear adaptor from , i cant seem to find them anywhere!!!
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Old 04-14-2007, 03:25 AM   #13860
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DNOS,

Thanks for your answer about the directivity. I'll try this weekend and let you know.

Is there any "hardware solution" to increase directivity of the XXX-S G+ at low speed (asphalt track) ?

Cheers.
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