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Old 12-02-2009, 04:39 PM   #13201
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Hi all...

I've made a research throught this thread and just haven't found the answer to my problem.

It figures that here in Mexico we run the Hobbywing EzRun 3000Kv system as a spec class.

I personally run with a JRX-S (hence I'm writting in this thread hehehe) and I've just jumped from the m03 minicooper class to Touring Cars.

My problem is that everytime I get on power too quickly, my car would swap ends and spin out. I have to be very very gentle (plus some -80% of throttle exponential) and the car still would be very loose. The car is awesome in fast corners but specially the ones that need maximum brake/acceleration.

What do I need to do in order for this to stop happening?

Let me put what I use in general.

Shock oil 30
Very smooth springs
Foam tires (40 all around)
3000kv Hobbywing system
36pinion/128spur
Tight differential up front and somehow lose in the back.

I run in a low-medium grip on asphalt

Thank you very much for your time!
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Old 12-02-2009, 08:52 PM   #13202
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Originally Posted by manthree View Post
Hi all...

I've made a research throught this thread and just haven't found the answer to my problem.

It figures that here in Mexico we run the Hobbywing EzRun 3000Kv system as a spec class.

I personally run with a JRX-S (hence I'm writting in this thread hehehe) and I've just jumped from the m03 minicooper class to Touring Cars.

My problem is that everytime I get on power too quickly, my car would swap ends and spin out. I have to be very very gentle (plus some -80% of throttle exponential) and the car still would be very loose. The car is awesome in fast corners but specially the ones that need maximum brake/acceleration.

What do I need to do in order for this to stop happening?

Let me put what I use in general.

Shock oil 30
Very smooth springs
Foam tires (40 all around)
3000kv Hobbywing system
36pinion/128spur
Tight differential up front and somehow lose in the back.

I run in a low-medium grip on asphalt

Thank you very much for your time!
Perhaps you could try some or all of the following if you're not already:
-only use tire traction sauce on the rear tires
-reduce the car's turning circle a bit
-loosen up the front diff to a normal amount
-make the front springs harder than the rear

If you can find a setup sheet for the JRXS, post it up with your complete setup along with some information about your track surface.
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Old 12-02-2009, 10:10 PM   #13203
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i would start by putting a softer tire in the rear sausce it full and sauce the front inside about a 1/4 to a 1/2 and make sure your ride hights are right.
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Old 12-03-2009, 05:06 PM   #13204
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Thank you very much, I will try everything that you're suggesting and I'll let you know...

Salud!
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Old 12-14-2009, 09:39 PM   #13205
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TTT
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Old 12-15-2009, 02:46 PM   #13206
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Default help help help!!

i need part #'s for the a-arms with BK ears...or where to get or make my own BK brackets. what are the specs and what do they look like?
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Old 12-16-2009, 07:05 AM   #13207
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i need part #'s for the a-arms with BK ears...or where to get or make my own BK brackets. what are the specs and what do they look like?
http://www.losipartshouse.com/servle...rts/Categories This has both on this page and you could order from them as well.
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Old 12-16-2009, 09:26 PM   #13208
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thanx yeti. i'll get them ordered asap.

i've surfed thru a lot of this form and have learned alot! but one thing i have been curious of is this.....how come nobody tried thinning the chassis plate and/or the two top plates down some? i got my car last week and been trying to read as much as i can on these threads. from what i understand, this car is MEANT to run CARPET/FOAM. i mean most production pics of this thing are showed with foam tires on it. that's one of the biggest red flag of all!!! rite on the box! and whats the first thing we all expect from a foam car? yep! thick @zz chassis plates!

so i took the two top plates off and sanded them down to 2mm each. the graphite was very inconsistant (stock thickness). high and low spots galore!! but now i have both plates where i want it. hopefully the thinner plates will allow for more flex therefore more grip. this will be my rubber ONLY car so i'm not too worried about putting the stiffness back in it. if this works out like i hope , i'll go ahead and sand the chassis down too. maybe 2.25 or 2.15mm. i know losi designed this car around thicker plates but i always wanted to see this car in action in "rubber spec" trim......any thiughts?
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Old 12-17-2009, 03:27 PM   #13209
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Nomaak
Removing the 4 rear posts dramatically reduces the torsional rigidity of the JRX-S. The Losi LCD thread by John Stranahan has the test results. I believe taking the 4 posts out lowers the stiffness to about the same as a XXX-S. This is what Iíve done to my VTA JRXS. Sanding the lower plate will give you problems with the screw heads not fitting right. It might also make the chassis more succeptible to damage in a crash.
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Old 12-17-2009, 03:32 PM   #13210
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Default foam on asphalt

Manthree
To improve the rear grip try the following:

I raced a JRX-S with foam on asphalt for many years. I found that running softer rear tires helped equalise the tire wear. You should also true the tires throughout the day to keep the front and rear diameters as equal as possible (the car does not like having unequal tire diameter). I ran tires with shore 35/32 and 35/30 front/rear (ambient temperature around 30 celcius and track temperature in mid 40 celcius). Do not use front foam tires made for nitro cars. Use carpet foam or rear nitro foam tires on all 4 corners. You may have to reduce the width to fit on the front. Also make sure your rear ride height is not too low which will make the car spin out if it touchs under acceleration. You can also try to reduce the ESC aggressiveness (punch).
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Old 01-05-2010, 05:04 PM   #13211
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Hello fellow JRX-S owners. I am in need of a little help. I am new to the TC Scene (Off Road for 5+yrs) and i am trying my best to get my JRX S ready for the VTA Class.

Well here is my dilemma.
Q1: I am trying to find out what LiPo will fit? I don't mind moding the car to make it fit.
Q2: What would be a good base line setup/hints/tips for a tight track?

right now i have a 17.5 SS Pro but now looks like the track I'm gonna go to is using the 21.5 then later in the yr they are switching to the 25.5 as to the rule change later this Yr.

Any and all help is greatly appreciated! Thanks
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Old 01-05-2010, 05:49 PM   #13212
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Orion Lipos 3600 3800 4000 i think carbon series fit. But you have to come up with a L shaped Plug or get a lipo Top brace and shave a bit of the casing.

Some of the Epics fit.
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Old 01-06-2010, 10:15 PM   #13213
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well i found some lipo packs that the plug exits on the corner. i would have to change the plug but thats no problem.

hobbypartz.com/83p-4000mah-2s1p-74-30c-car.html (how many posts do you have to have till you can post a URL?)

They are 4000mAh 30C hard case and are only $28

i tried to contact them via live chat to see what the dimensions are but never got ahold of anyone so i will try again later today.
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Old 01-06-2010, 10:19 PM   #13214
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Quote:
Originally Posted by Tuner EM View Post
Nomaak
Removing the 4 rear posts dramatically reduces the torsional rigidity of the JRX-S. The Losi LCD thread by John Stranahan has the test results. I believe taking the 4 posts out lowers the stiffness to about the same as a XXX-S. This is what Iíve done to my VTA JRXS. Sanding the lower plate will give you problems with the screw heads not fitting right. It might also make the chassis more succeptible to damage in a crash.
Is this something i should do as well since i am getting ready to do VTA?
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Old 01-07-2010, 09:40 PM   #13215
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Default rear post

yes, remove the rear posts for more grip. this should help in VTA. use the 2 degree rear pin mount too (helps with rear grip coming off corners). i modded my car very heavily to make it an all purpuse road racer but i had varied results. just couldn't seem to get it tight enuff with out sacrificing front grip. i been running my HPI Pro3 lately and have found some things i THINK i might be able to carry over to the losi (which is still waiting to be bought down at the hobbyshop)

but what ever you do...NEVER, I SAY NEVER use the off-set hubs in the rear. this makes the car waaaay to free on all but the highest traction situations. (carpet with foams)
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