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Team Losi JRXS Type-R

Old 05-18-2009, 01:13 PM
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Originally Posted by Dragonfire View Post
I only have just over a 100gms on my chassis. All of it is in front of the battery. I imagine that if I had a metal tray then my chassis would certainly have rear weight bias. They other element is that a steel tray effects the chassis. It reduces flex and stores tweak if it gets twisted.


The layout would most likely be almost identical to the pro3, but with losi parts. The explination I have been using is this. Get a weight and tie it to the end of a string. Swing it round as fast as you can. You will find there is a limit to how fast you can go. Now grab the string closer to the weight and try again. You will be able to swing it around alot faster. This is the same effect we are looking at with this mod. The JRXS chassis is the best chassis on the market for centering weight l/r but this results in a large f/r split. Considering that everyone runs more weight on one side of the chassis to balance their speedy, Why not just move the servo there and tighten up the f/r split. I can see any negatives to this so far. The million dollar question is do we move the layshaft forward with the motor or move it behind the motor? I like the idea of moving the layshaft backwards. This gives you a long front belt and inherently more steering as a side effect.


Hello there all, even though I don't race anymore, I can give you some input on moving the motor forward on the car. When the type R was still in it's prototype stages we had a car with the motor moved about 20mm more forward than the placement now, and yes the servo was mounted on the side of the chassis. We ran the car some at the 2006 Novak Touring car champs. The car ran ok, but it did not have the steering of the rear motor car, it was very smooth around the track but lacked in the rotation department. I know that Todd ran the car car some more back in CA, but it showed no big advantages over the prototype we were already running, so thats why for the production car the motor remained in the back. Just a little fyi, because I dont think it would be worth all the work and $ it would take to make those changes.
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Old 05-18-2009, 03:03 PM
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Originally Posted by Andrew Gray View Post
Hello there all, even though I don't race anymore, I can give you some input on moving the motor forward on the car. When the type R was still in it's prototype stages we had a car with the motor moved about 20mm more forward than the placement now, and yes the servo was mounted on the side of the chassis. We ran the car some at the 2006 Novak Touring car champs. The car ran ok, but it did not have the steering of the rear motor car, it was very smooth around the track but lacked in the rotation department. I know that Todd ran the car car some more back in CA, but it showed no big advantages over the prototype we were already running, so thats why for the production car the motor remained in the back. Just a little fyi, because I dont think it would be worth all the work and $ it would take to make those changes.
good to see you posting andrew......

what has been going on with you??
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Old 05-18-2009, 04:26 PM
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Originally Posted by Andrew Gray View Post
Hello there all, even though I don't race anymore, I can give you some input on moving the motor forward on the car. When the type R was still in it's prototype stages we had a car with the motor moved about 20mm more forward than the placement now, and yes the servo was mounted on the side of the chassis. We ran the car some at the 2006 Novak Touring car champs. The car ran ok, but it did not have the steering of the rear motor car, it was very smooth around the track but lacked in the rotation department. I know that Todd ran the car car some more back in CA, but it showed no big advantages over the prototype we were already running, so thats why for the production car the motor remained in the back. Just a little fyi, because I dont think it would be worth all the work and $ it would take to make those changes.
Thanx for the input. I am less and less tempted to go down this road at the moment anyway. I have tuned this chassis now and am far faster with it than anything previous vs the normal ppl I race. Last weekend I decimated the mod field at a warmup event and at the state titles I was on pace with one of Australias fastest drivers (B finalist at the last worlds). It is not the driver but that chassis that is making that difference.
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Old 05-18-2009, 04:36 PM
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Originally Posted by Andrew Gray View Post
Hello there all, even though I don't race anymore, I can give you some input on moving the motor forward on the car. When the type R was still in it's prototype stages we had a car with the motor moved about 20mm more forward than the placement now, and yes the servo was mounted on the side of the chassis. We ran the car some at the 2006 Novak Touring car champs. The car ran ok, but it did not have the steering of the rear motor car, it was very smooth around the track but lacked in the rotation department. I know that Todd ran the car car some more back in CA, but it showed no big advantages over the prototype we were already running, so thats why for the production car the motor remained in the back. Just a little fyi, because I dont think it would be worth all the work and $ it would take to make those changes.
Thanks for the info. Keep it coming.

Was the testing you mentioned done with Lipo's? I imagine back in 2006 probably not. That makes a big difference. Moving the motor and NiMH's forward would just create a forward weight biased car that would push.

As Dragonfire said, to balance a type r F/R with a lipo you need a lead up the front of the car. You end up with lots of weight close to both axels. We just want to squash that in to the center a bit. Luckily Dragonfire seems to be very sensitive to small setup changes(as well as a very fast racer) and should give some good feedback when we get to testing.
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Old 05-18-2009, 05:15 PM
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Will most parts for the JRXs type R fit the JRX-s? including the battery tray?
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Old 05-18-2009, 05:58 PM
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Originally Posted by EJF View Post
Will most parts for the JRXs type R fit the JRX-s? including the battery tray?
Front and rear hubs, shocks, sway bars, bumper assembly, diff eccentrics, and turn buckles are about the only common parts between the two cars. Everything else is different including the battery trays. You can use the layshaft from the old car for the new one with no mods and the bearings are the same on both cars except maybe some of the steering linkage bearings. Chassis's are completely different as well as shock towers and bulkheads.
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Old 05-19-2009, 07:31 AM
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Hey Andrew,
With the ROAR Nats so close to home any chance of coming out of hiding for one weekend?
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Old 05-19-2009, 09:29 AM
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Default Lay shafts

Finally got some layshafts turned on the cnc lathe today. I'm very happy wth the finish. Perfectly parallel 4mm shaft. Onto the cnc mill tomorrow to finish them off.
Attached Thumbnails Team Losi JRXS Type-R-layshaftmachining1.jpg   Team Losi JRXS Type-R-layshaftmachining2.jpg   Team Losi JRXS Type-R-layshaftmachining3.jpg  
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Old 05-19-2009, 01:53 PM
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Originally Posted by Andrew Gray View Post
Hello there all, even though I don't race anymore, I can give you some input on moving the motor forward on the car. When the type R was still in it's prototype stages we had a car with the motor moved about 20mm more forward than the placement now, and yes the servo was mounted on the side of the chassis. We ran the car some at the 2006 Novak Touring car champs. The car ran ok, but it did not have the steering of the rear motor car, it was very smooth around the track but lacked in the rotation department. I know that Todd ran the car car some more back in CA, but it showed no big advantages over the prototype we were already running, so thats why for the production car the motor remained in the back. Just a little fyi, because I dont think it would be worth all the work and $ it would take to make those changes.
I'm surprised you remembered you login password... How's life been treating you?
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Old 05-19-2009, 04:05 PM
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Originally Posted by Pablo Diablo View Post
Finally got some layshafts turned on the cnc lathe today. I'm very happy wth the finish. Perfectly parallel 4mm shaft. Onto the cnc mill tomorrow to finish them off.
are you able to ship in USA?
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Old 05-20-2009, 07:55 AM
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Originally Posted by Pablo Diablo View Post
Finally got some layshafts turned on the cnc lathe today. I'm very happy wth the finish. Perfectly parallel 4mm shaft. Onto the cnc mill tomorrow to finish them off.
Sweet... can't wait to try them out this weekend if they are done... See you at the MMM.
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Old 05-20-2009, 12:18 PM
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Originally Posted by YmeBP View Post
I may have asked this before but .... with this many pages in the thread I can't find it so i'm putting it in the title this time to make it easily searchable (hence the godzilla keyword ).

Situation:
Low temperature (track was 56*) medium bite surface relatively high speed

Major areas of my setup :
45/40 front rear shock oil, 17.5 springs all the way around
both diff's low (tried high/low front rear as well)
high roll center front (tried low low as well)
Low roll center in rear (1 washer under front roll center thingy)
tried both jr links and camber links in front
rear is 4 inside and farthest one from shock tower on the hub (B i think)
rear shocks are straight up and down
front shocks are second hole from up and down.
RP24 tires
6.5mm ride height, and 2mm droop all the way around.

I was really loose in the rear coming out of the corners, going in the corners i was good.

I also tried both over drive (smaller front pulley) and even.

What steps would I take to lock the rear of the car in more.
Anyone got anything i can try?
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Old 05-20-2009, 04:54 PM
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Default servo horn

I have a futuba servo in my jrx-s type r it takes the the 25 servo horn but it looks like i have to buy the whole servo steering kit or can i just buy the servo horn or does anybody else make one that will work. thank
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Old 05-20-2009, 05:49 PM
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Originally Posted by YmeBP View Post
Anyone got anything i can try?
The easaiest thing to try would be more rear toe. I run 3.5 everywhere.

Another big factor is the diff (something I have been working on a lot recently). It needs to be smooth. If its gritty or too tight (excessive limited slip effect) you will struggle to use power out of corners. The biggest advance I have made with my diff is to remove the cage from the thrust bearing and use more thrust balls. You can fit 3 extra without the cage and it makes a noticable difference on the track.
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Old 05-20-2009, 11:56 PM
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Originally Posted by YmeBP View Post
Anyone got anything i can try?
Is this on asphalt?

I found a 41 tooth front pulley will make the car twitchy, rear felt much more stable with equal pulley sizes.

I'm with Dragonfire on the rear diff --My rear diff was going out (loose) and it also caused the car to be loose in the rear and not predictable on power and in chicanes. More rear toe will give you more forward bite on accel. I run 3* to 3.5* in both my cars as a starting point.

I would run a level rear hinge pin, says you have a .030 washer in front.

Late in a run if the rear is loose but it was fine at the start of the run, it's most likely tires overheating try 27's/28's.

Those are what I have found on different instances.
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