JRX series set up discussion

[JK Racing]

car ran fantastic. little off power low speed push, but a front tire change almost eliminated that. i had cut the wing wire too short, measured how long without the body with the body on it barely went in 1/4" at most.

I ran 17.5 in an "open" class, there were only 6 buggies overall, 4 stock (some boosted, some blinky) and 2 mod. a TLR driver was TQ (mod), I was 2nd qualifier (using the wrong front tires). Horrid start in the main saw me in 4th after 2 laps (no wing). I sucked it up and just started turning lap after lap, ensuring the hit the doubles smooth, the double into triple even smoother and kept my lines tight and clean. I was in 3rd, first place was coming up to lap me with about 1 minute left (laps were about 24-27 seconds) the leader lost a front wheel. On the last lap, last 1/2 of the track, 2nd place had caught him and I was only a couple feet behind. They tangled and I shot right between them as the turn marshal went for their cars...the turn marshal, not knowing I just made the pass for the lead, tossed the 2 cars OVER the pipe right in front of me...I nailed the brakes to not pile drive one of the cars and slid a little off kilter...I jumped back into the throttle and passed the 3 wheeled buggy, and was nose to tail with the other car as he passed over the line, .02 seconds ahead of me. I was robbed...the race director did see it, but gave the other guy the win anyways. It was just a club race, nothing special or any prizes so i didnt argue, I knew how i did. So did most the other racers, they couldnt beleive a 20+ year old buggy was out there tearing it up. 2 other guys admitted having JRX2's sitting at home, and they both were asking me if I would help them set them up to race (especially if they work as good as mine did).

On to set up discussions:

Front:

swept arms, LXT carriers/pro axles
.9 shock bodies, .6 shock shafts, JRXT/Pro front tall tower, silver buggy front springs
middle on tower, outside on arm
camber links middle on tower
arms level

Rear:

5 link, .050 shorter links in the front side
.9 shock body, .9 shaft, 5 link rear tower, red buggy/truck rear springs
camber link in original lower hole (not inner near transmission)
shock bottom all the way back toward the rear
slider shafts level

Other:

Futaba 9301 servo, RPM steering
Mamba Max Pro Speedo, 15 degrees boost/turbo 3000-15000 engagement
17.5 Losi Xcelrion motor
33/78 on LRM tranny, Thorpe gears, no slipper
Checkpoint 5400/24C lipo battery
Spektrum receiver

[bearrickster]

Wow that sounds like you had a great day. and it good to hear the old girl can still mix it up with the kids.

[madweazl]

I cant wait to start racing a JrX Pro I picked up a couple weeks ago. Guess I'll need to source some extra arms just in case I'll probably keep it to vintage specific events at our track as I'm not sure I'll be able to hang in the expert mod class with it. They did just start a no boost stock class so that may be a good option for it too.

Edit: think that's what I'm going to do. What wheels did you use?

[JK Racing]

Currently using 22 rear wheels with a traxxas hex over the stock rear axle (nut fitment issues). And B4 front wheels with a spacer on the inside of the bearings (no fitment issues).

is SDRC going to do a vintage specific class? if so, i could make the trek down there from Orange County and we could tear it up together

With today's batteries & motors, blinky 17.5 is still plenty fast, I'm going to dial into my speedo and play with the settings to put it back into blinky (no timing) mode. Remove the fan and start working on gearing. The LRM tranny held up well to my abuse, i know i made some full throttle landings on Saturday night.

[madweazl]

Currently using 22 rear wheels with a traxxas hex over the stock rear axle (nut fitment issues). And B4 front wheels with a spacer on the inside of the bearings (no fitment issues).

is SDRC going to do a vintage specific class? if so, i could make the trek down there from Orange County and we could tear it up together

With today's batteries & motors, blinky 17.5 is still plenty fast, I'm going to dial into my speedo and play with the settings to put it back into blinky (no timing) mode. Remove the fan and start working on gearing. The LRM tranny held up well to my abuse, i know i made some full throttle landings on Saturday night.

There seems to be quite a bit of interest in doing some vintage racing down here but who knows what will actually happen. Half the people that want to run vintage want to run modern electronics which is something I dont want to see.

Be fun to whoop up on the new cars in the stock class though I'll have to play with some dyes to figure out a good match to the old Losi logo red wheels to match a box art paint job.

[JK Racing]

I am using both modern electronics and modern rubber. the modern electronics make the car reliable, while the modern rubber lets the car stick to the track like the current cars.

vintage electronics (speedo's) werent designed with lipos in mind, and the advantages of lipo over nicad or nimh are amazing. i have and do run my gold pan with vintage electronics & brushed motors, with lipo, it is competitive with 17.5 brushless no timing, but still using modern rubber. but decent brushed motors (and the items needed to keep them in tip top shape) are getting more and more scarce as brushless has taken over, and with the low cost of some of the imported chinese system, cheaper to get into than an equivalent brushed system. if you have your brushed set up still, by all means, run it, just keep an eye on the lipo to not over-discharge the battery (if you are only racing, this is almost nonexistant). there are several lipo alarms that can be purchased relatively cheap and do the job if you want to run 10-15 minutes during practice (but be wary of overheating the brushed motors at that point).

there have been many looky loo's when i run my vintage stuff, occasionally one or 2 others do show up and we have a go at it. i'm guilty myself, i have a new 22 sitting there waiting to be track driven at a moments notice. but i am going to start running stock/vintage, mod/modern as the classes grow and can be separated (or larger events when there are plenty of buggies and the rules dont restrict running both stock/mod).

[madweazl]

I am using both modern electronics and modern rubber. the modern electronics make the car reliable, while the modern rubber lets the car stick to the track like the current cars.

vintage electronics (speedo's) werent designed with lipos in mind, and the advantages of lipo over nicad or nimh are amazing. i have and do run my gold pan with vintage electronics & brushed motors, with lipo, it is competitive with 17.5 brushless no timing, but still using modern rubber. but decent brushed motors (and the items needed to keep them in tip top shape) are getting more and more scarce as brushless has taken over, and with the low cost of some of the imported chinese system, cheaper to get into than an equivalent brushed system. if you have your brushed set up still, by all means, run it, just keep an eye on the lipo to not over-discharge the battery (if you are only racing, this is almost nonexistant). there are several lipo alarms that can be purchased relatively cheap and do the job if you want to run 10-15 minutes during practice (but be wary of overheating the brushed motors at that point).

there have been many looky loo's when i run my vintage stuff, occasionally one or 2 others do show up and we have a go at it. i'm guilty myself, i have a new 22 sitting there waiting to be track driven at a moments notice. but i am going to start running stock/vintage, mod/modern as the classes grow and can be separated (or larger events when there are plenty of buggies and the rules dont restrict running both stock/mod).

If I run the stock class with it, I'll run new rubber and brushless but if we do a vintage class, I want it to be all vintage (NiCd and all).

[Garage Hack]

I remember when I got my first production JRX and Rick Hohwart still had his Prototype and hadn't gotten the new produciton parts yet. We were at the Regionals in AZ 1988 Region 12 if I remember. Not sure if it changed or not. It was the qualifier for the 1989 Worlds. We were cleaning our cars and I started measuring parts and saw that the prototype lower links were a little shorter than the production ones. I put his proto lower on the front and put my prod lower on the rear and that gave us more toe in. Stupidly I told the Losi guys at the track the next day and they did the same. Cars all got better traction and they all did better that day and Jack Johnson beat me for the last spot on the USA team. Guess I should have waited till after i guess...lol. So after the race they got the proto mold out and made a run of lower arms and sold them as toe in options for the car till the A arm car came out. Just a little story from back in the day.

These stories are what make this board so awesome. Thanks for sharing!

[Johanp]

Love that story!

Me and another Losi driver contacted Losi for setup help before a regional race here in Sweden.
We got a fax back from Jack Johnson!
Still have a copy of it.