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Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 9:08 pm
by Charlie don't surf
The track that you were on seems kinda small, and with the lipo's and the rear end configuration that car will react way differently to springs. I think that the 3.7 is way much. Try some pinks or whites to help it change direction quickly, and as far as jumping attitude---throttle control :wink:

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 9:16 pm
by RCveteran
Yes it is a smaller track, I actually enjoyed it, the other track here I can get to is a very big one, different experience all together. I found myself really focusing on turn in points and planning my line better which I think will help my driving overall. The tight confines seemed to force it more, at least im my driving mind if that makes sense. There is just less room for slopiness so to speak.

Yes I need to work the throttle control better on the jumps. I will try some pink, red and white springs next go around.

With the JRXpro battery box the Lipo is where it is, I can't move it so that leaves me with weights but there are not a lot of options on this chassis.

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 9:18 pm
by Charlie don't surf
Why are you concerned about the weight?

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 9:19 pm
by RCveteran
Not the actual weight but was thinking would it help to place some lead weight on the nose.

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 9:29 pm
by Charlie don't surf
Sorry, I stated my question incorrectly-why do you want nose weight?

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 10:20 pm
by RCveteran
Just thinking out loud, not sure I do, just thinking since it seemed so rear end happy off the jumps and all the modern cars seem to place weight here and there.

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 10:28 pm
by GreenHell
Cool build!

17.5 on that track is more than enough.

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 10:35 pm
by JK Racing
Rear end happy...nose high or rear high? Nose high can be too much throttle as you leave the jump.

Re: JRX2 5-link racer build

Posted: Thu Jan 06, 2011 10:39 pm
by Charlie don't surf
RCveteran wrote:Just thinking out loud, not sure I do, just thinking since it seemed so rear end happy off the jumps and all the modern cars seem to place weight here and there.
Most of the car's jumping attitude is controlled by the spring rate, the oil weight and the piston-ie, the car will be very "poppy" off jumps with heavy damping and heavy springs which can be good and bad, and be more nose up with a stiff front spring and or too light of oil weight- Normally the placement of lead as ballast is more of a weight transfer trick.

Re: JRX2 5-link racer build

Posted: Fri Jan 07, 2011 7:13 pm
by RCveteran
It's definitly nose up and the rear seems to smack easy so say on the small double unless I hit just right it seemed the rear woudl smack off the jump and actually send the car tumbling, on the bigger more launch friendly jumps definitly nose up.

As a side, I installed the kit for a XX A-3111 dual disc slipper, fit right onto my single slipper shaft so now spurs are a piece of cake.
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Re: JRX2 5-link racer build

Posted: Fri Jan 07, 2011 7:39 pm
by JK Racing
What are you running for Pistons/Oil? I'm thinking 56 (pink) on all 4 corners and leave the oil, or maybe go 35 all around. I personally usually have my front end a bit "heavier" in oil than the rear, so maybe 37.5/35.

Also, something to think about, what is the front rear ride height ready to race? Maybe adjust the nose a touch lower than the rear (or rear higher than the nose :mrgreen: ). I know this has a lot to do with corner entry/exit, but maybe the chassis slap could be attributed to running the car too low all around?

Re: JRX2 5-link racer build

Posted: Fri Jan 07, 2011 7:41 pm
by jwscab
is that 3300kv associated motor equivalent to a 17.5 turn? I am thinking of picking up that eraser combo but in 3900kv.

Re: JRX2 5-link racer build

Posted: Fri Jan 07, 2011 7:43 pm
by JK Racing
KV matches a 13.5, but most local tracks to me allow it to run with the 17.5s, they say it isnt all the fast (like a good 13.5)

Re: JRX2 5-link racer build

Posted: Fri Jan 07, 2011 7:54 pm
by RCveteran
I agree its probably between the two in reality. On soft throttle profile on my ESC it is closer to a 17.5 but on the hard throttle profile it is for sure faster closer to a 13.5. It's not a bad motor for what you can get them for taken new out of all the RTR's.

Re: JRX2 5-link racer build

Posted: Sat Jan 08, 2011 3:56 am
by JK Racing
are you using the AE speedo also? I'm short a sensorless speedo, been thinking of picking up a sidewinder to put in the SCT (with the TRX Velineon motor). I may pick up one of these combos also, I see they can be had for under 100.