Fast XXXS

iTrader: (51)

What would be better, running the rear diff looser or tighter stop the tail comming loose when getting on the throttle? Would it help at all?

losi nut

iTrader: (1)

A tight rear diff will contribute to a tail happy situation. You only want to tighten it enough so it's not chirping(?) on acceleration. It does make a difference.

Fast XXXS

iTrader: (51)

Thanks for that losi nut, i will test it next time at the track.

R.Fenstermacher

iTrader: (20)

Thanks for everyone's help on the set up, I'll try it this weekend. I have another question, do any of you have a Novak GTB Brushless system on your JRXS that I can see a picture of. I'm not sure were would be the best place for it on the chassis. Thanks in advance.

rinkrat99

Hi all

On Craig Xavier's 2006 Nationals setup he mentions 2 0.050" shims under the pivots that are in the high position. Is he using two on each corner of the suspension for a total of 0.100"? So thats four for the front and four for the rear of the front suspension arms right?

Here is part of the thread from June 2006.





Johnny Wishbone
Tech Adept


203 Posts Since Feb 2006

Old 06-15-2006, 02:57 PM Default View Public Profile Send a private message to Johnny Wishbone Reply With Quote
Post #11917
Mr Pookyt, I have a question that I just want to get straight in my thinking. I'm looking at Craigs setup sheet, as well as other ones and I just want to make sure I'm understanding this right as I'm reading them. He is running 2 shims under his pivot block and in the high position, so does this mean he is running the same shims under the rear pivot of the front of the car? If it was just under the front this would be considered a "kick" setting rather than a "roll center" setting, is this correct or am I inline for another smack. I just find it confussing when/or if the adjustment is being made at the same point but using 2 different places to indicate it. To me it would make more sense to have all three togeather on the sheet, if what I'm understanding is true. Thanks ahead of time for clearing this up for me. JP or Doug please feel free to jump in on this one as well.
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POOKYT
Tech Champion

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Jonesboro, AR

5,130 Posts Since Oct 2002

Old 06-15-2006, 04:00 PM Default View Public Profile Send a private message to POOKYT Reply With Quote
Post #11918
Quote:

Originally Posted by Johnny Wishbone



Mr Pookyt, I have a question that I just want to get straight in my thinking. I'm looking at Craigs setup sheet, as well as other ones and I just want to make sure I'm understanding this right as I'm reading them. He is running 2 shims under his pivot block and in the high position, so does this mean he is running the same shims under the rear pivot of the front of the car? If it was just under the front this would be considered a "kick" setting rather than a "roll center" setting, is this correct or am I inline for another smack. I just find it confussing when/or if the adjustment is being made at the same point but using 2 different places to indicate it. To me it would make more sense to have all three togeather on the sheet, if what I'm understanding is true. Thanks ahead of time for clearing this up for me. JP or Doug please feel free to jump in on this one as well.




Yup!! Yopu got it! He is running 2 .050 shims under the bar and under the small blocks. And yes, it might be different but he would indicate that on the sheet by showing "Anit-Dive" or "Kick" on the front.

On the rear arm to the front thing, I actually broke my BK rear arm Sunday and used my spare regular arm with a BK bracket. I have looked at doing this thing but man its really just too much work and I am too lazy!!! LMAO

Brant

POOKYT

rinkrat---Yes......two .050 shims for a total of .10 under each corner.

Brant

rinkrat99

What are your thoughts with regards to Craig Xaviers Asphale setup? Particularly the 41R pulley along with the front spool and the 0.100" shimmed roll centers?

What effect is this gonna have on the car?

It sounds like we are keeping the rear roll center LOW and thus keeping the weight transfer towards the back to gain traction.

Thoughts?

Island Losi

iTrader: (3)

where can i find the/a setup Todd or Matt used for he track at the 2006 IFMAR worlds? the track i run on is very similar but i can't seem to carry as mush speed thought the hair pins as i want to. i have a problem with the front of the car bottoming out under brakin. i using the travel limiters so it would not bottom out but now the shock stroke is very small. im running a brushless mamba 6900 system.

masterhit

iTrader: (16)

The problem is that particular set-up is for the 3-deck car if my memory serves me correctly. I do know that they were using the rear engine for sure. So the weight distribution would be a bit different.

Basically what you need to accomplish is reducing weight transfer to the front or minimize its' effects on the vehicles dynamics. You can do this a few ways. Stiffer front springs, reduced rear droop, heavier front dampning to a lesser extent, and adding anti-dive. If you feel it is only hitting on the outside during the turn you can also raise the roll center to reduce chassis movement and play with sway bars. Most asphalt set-ups call for pretty high roll center settings.

But when all else fails, have you tried the Numan set-up?

Mike Slaughter

Edit for clarity.

masterhit

iTrader: (16)

And if you want to get your full geek on....

From http://www.racing-car-technology.com.au/wgttransex.htm

And two components of Suspended Weight Transfer:
Geometric Weight Transfer - due to the component of lateral force, applied directly at the Roll Centre (RC). Geometric WT is reacted directly through the suspension linkages, and does not induce body roll.
Elastic Weight Transfer - due to the component of lateral force, applied at the Suspended Mass CG, and does induce body roll. This force is reacted in the springs, anti-roll bars and shocks, and is the only one of the three components of total weight transfer that does induce body roll.

It is clear that low roll centre give little geometric wt and most of the weight transfer goes through the springs (elastic wt), and is therefore delayed by the time it takes for the vehicle to take a set. Conversely, with high roll centre most of the weight transfer precedes the body roll, leaving a smaller amount of weight transfer to go through the springs.

Island Losi

iTrader: (3)

they used the rear motor car but i still wanted to see the setup. i used the numan setup to start with but it was too soft with both front and rear chassis scrapping the ground under braking and acceleration. i when up to 35 front and 17.5 rear springs but i lost turn in and cornering speed around the hairpins. is seems as though i have to tap the brakes to get the car to turn or just slow down more. thats for the info

rinkrat99

Hi all

I ran my JrXs for the first time today on asphalt and was wondering how people are getting a sub 6 FGR with a 118t Spur? Some of these motors need a 5-6 FGR and that would correlate to a 43t pinion.

Thanks

Mike Haynes

iTrader: (2)

With the 118 spur you can fit pinions in the area of 45ish with no trouble...robinson sells them.

Wasabi

I was wondering if anyone has tried using the new front upper arms from the JRXS Type R on the JRXS Pro? Will it even fit?

429racer

iTrader: (19)

They use the same castor blocks, so I would have to say yes.