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Old 08-28-2009, 08:34 AM
  #10351  
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Originally Posted by nitrobeast View Post
On carpet your gonna need a unmodified top deck. I can see it traction rolling at every corner
Yeah, Rui I ll be carrying several upperdecks with me soon, see ya at Jackson Sunday
Originally Posted by jrxs-r View Post
Couldn't have said it better myself.... +1!
TY
Originally Posted by jrxs-r View Post
More info here on the turnbuckles for the JR Link

http://www.rctech.net/forum/3510891-post4989.html
Sweet!
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Old 08-28-2009, 09:31 AM
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I run a JR link with the ball cup cut down so I can run a small turnbuckle in there. With this setup I can achieve up to 3 degrees camber which is plenty for rubbers. I have tried the normal ball stud link but the lack of steering drove me crazy. I imagine it would be fine on high grip tracks though.

Took the losi for a run again with flex setting on a low grip track. Last time I ran here I struggled alot with the losi natural level of grip. This time the chassis was off the ball straight away and while wondering what was going on I noticed every other car doing donuts. So the problem was the track. I took a 17.5 car for a run which was awesome fun as I had it sideways out of every corner.

So I sat down for an hour and rebuilt a few diffs while others cleaned the track up for me. Out again and the car was sweet. Plenty of steering over the majority of cars on the track and good in and out of the corners. Since I turned the lock down a little earlier I decided to leave it there so I could compare runs. Anyway I quickly did back to back runs with the front two screws of the rear bulkhead in and out. In feel the chassis has the same flex initially but with the bulkhead screws out it would continue to flex a lot further before stiffening up. Simply put the bulkhead screws out gave a more planted car but lacked high speed steering where the screws in gave a much better feel and you could keep your foot on the gas more around fast corners with less brakes. Anyway the flex was not as much as you might think looking at my deck mods.

We ran 3 races since there was only 7 10.5 drivers and everyone was cool with having some fun so I got the chance to test the car in race conditions.

1st run with my usual setup. I started mid pack and quickly moved to 2nd. Follow the leader (2006 Australian Stock Champ) for most of the race constantly putting pressure on him. I was able to move around behind him a lot and maintain his pace. Eventually I forced his error and went on to take the win. Best lap of 12.0 (Best other 12.2)

2nd run was usual setup but high roll centers in stead of low. Initially the car felt good in the warmup laps but a little loose. Very quickly into the run (I started back of grid) and the goop started to lose effect and my steering started to disappear. Thankfully everyone around me was busy pushing beyond their limits so was able to run away with the win easy but the car lost low speed performance and was moving around a little lacking that planted feel. Best lap 12.2 (Best other 12.1)

3rd run and went back to low roll centers but changed rear link position to promote a little more chassis roll. Instantly the car felt very good to drive and once again from the rear of the grid I was all over anyone in front of me and quickly made my way through to 3rd. From there I had a few laps to catch the gap but unfornatly the driver had a vege moment and missed a corner. In their rush to get back into position they back across the corner and right into my path as I was already comitted to the turn. So I sat there waiting for him to be marshalled (whole field went past) then back underway and I went straight past him cleanly this time. I qwickly dispatched most again loving the feel the chassis was giving me. Back up to the lead battle and joined in the fun taking 2nd but 1st had been given a decent chance to drive away so no chance for the triple. Infact I ended up 3rd as 3rd place following me made a big deliberate cut of the track and took 2nd. Was seriously funny at the time lol. Anyway after all the speed I though I had the best lap was only 12.1 (Best other 12.1 also). I guess the biggest difference here was the increased roll and therefore drag made the car easier to drive into corners hard and therefore felt fast even though its lack of corner speed made it slower.

Still all in all I once again found low roll centers better even with the flexy chassis. The increased grip I am getting and this testing shows I prolly need to look more towards less roll from swaybars and springs rather than roll centers to get some more speed but with the bulkhead screws in some of the high speed steering was back and I am liking this flex setup more and more.

As note I also adjust weight ratio from 52/48 to 53/47 F/R.
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Old 08-28-2009, 10:39 AM
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I've got a JRX-S R on the way! Bought a real nice used car with ceramic bearings, Ti screws and tons of spares.

Anybody run the steel lipo tray? My lipos only weight about 240g, so I need all the extra weight I can to make the 1500g limit we've got here this year. Does the steel tray effect the car's flex in a big way?
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Old 08-28-2009, 10:42 AM
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Originally Posted by WheelNut View Post
I've got a JRX-S R on the way! Bought a real nice used car with ceramic bearings, Ti screws and tons of spares.

Anybody run the steel lipo tray? My lipos only weight about 240g, so I need all the extra weight I can to make the 1500g limit we've got here this year. Does the steel tray effect the car's flex in a big way?
Just about everyone was running them when the weight limit was 1450g here I never noticed a difference between the 2 other than if for some reason your battery was putting pressure on the top deck you could tweak the car with the metal one, (like running the foam that comes with the car under the topdeck and a big lipo).
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Old 08-28-2009, 11:51 PM
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Default Excel Setup worksheets

For those who have downloaded this in the past, here is a revised reversion with new tips and additional items to help you keep track of your progress.

For those of you who are running Excel 2007, you can now save directly to PDF, verses creating new worksheets!!

But if you are running Excel 2003 you do not have this capability, unless you are running it on a Mac where this feature is available.

Enjoy..
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sample.pdf (171.9 KB, 119 views)
File Type: zip
Excel 97 to 2003 worksheet.zip (49.2 KB, 26 views)
File Type: zip
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Old 08-29-2009, 04:10 AM
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Thanx MaxRain... I'm sure it will come in handy.
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Old 08-29-2009, 06:05 AM
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I ran my car in the VTA class and it was great! (TQ and won)
I am using the diff. height setting is stock. I believe it is high front and low rear. How does the height effect the handling of the car? Does some people run all low or all high?
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Old 08-29-2009, 06:19 AM
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Originally Posted by Mugen10 View Post
I ran my car in the VTA class and it was great! (TQ and won) I am using the diff. height setting is stock. I believe it is high front and low rear. How does the height effect the handling of the car? Does some people run all low or all high?
Since speaking with Gil at the '05 'birds, I've always run the diffs at a height that keeps the axles as level as possible. He explained the affect that "pin drag" has on bound/rebound of the suspension, and while I can't remember the details, the jist is that flat axles reduces the affect. Somebody good with offroad could explain it better.

Since the advent of the big diameter foam tires and running rubber indoors, I've always run the diffs as high as possible.
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Old 08-29-2009, 06:52 AM
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Thanks I will give the high diff setting a try on test day.
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Old 08-29-2009, 08:48 AM
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Originally Posted by Greg Sharpe View Post
Since speaking with Gil at the '05 'birds, I've always run the diffs at a height that keeps the axles as level as possible. He explained the affect that "pin drag" has on bound/rebound of the suspension, and while I can't remember the details, the jist is that flat axles reduces the affect. Somebody good with offroad could explain it better.

Since the advent of the big diameter foam tires and running rubber indoors, I've always run the diffs as high as possible.
I already wrote that a month ago on my blog
http://dajohnwee.blogspot.com/2009/0...losi-jrxs.html

when a angled axle spins it tend it to straighten out it self and that give bind on every pin that is in angle, remember all the off road vehivhles "starting ride hieght" is dog bone level? cause they designed the tranny case height, roll center (suspension mount), hub carrier to be that way.

Originally Posted by Mugen10 View Post
Thanks I will give the high diff setting a try on test day.
no thats not it, you will need to adjust the diff height according to "roll center block height, ride height" like a picture attached
Attached Thumbnails Team Losi JRXS Type-R-jrxs_rear_bone_flat_logo.jpg  
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Old 08-29-2009, 08:57 AM
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The high diff will keep the car at that end a little flatter than a lower diff. Typically high front, low rear is good for rubber tires or at least a good starting point. If your car is too responsive lowering the front diff will take some initial cut out of the car but keep the front in of the car in the turn longer.
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Old 08-29-2009, 12:42 PM
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Pete, please try these zip files.

I zipped them using the windows default program. The first batch was zipped using WinRAR. Before posting I didn't bother to check if they were ok.
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Excel 2007 worksheet.zip (121.4 KB, 18 views)
File Type: zip
Excel 97-2003 worksheet.zip (49.9 KB, 12 views)

Last edited by MaxRain; 08-29-2009 at 12:54 PM.
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Old 08-29-2009, 07:56 PM
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I run my diffs full high front and rear... I have yet to prove to myself that the chassis goes differently in any configuration but I like the idea of having my CG a little higher to promote more roll as this chassis is always fast left to right. I also like to keep my rear diff away from all the dirt on the surface although ~3mm doesn't make much difference.

da_John_wee: grab a dremel and cutting disc and put a few "nicks" in those springs to tell you what they are. Its much better than losing those stickers. I put 1 mark on 10.5, 2 on 12.5, 3 on 15 and so on...
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Old 08-29-2009, 08:22 PM
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Originally Posted by Dragonfire View Post
I run my diffs full high front and rear... I have yet to prove to myself that the chassis goes differently in any configuration but I like the idea of having my CG a little higher to promote more roll as this chassis is always fast left to right. I also like to keep my rear diff away from all the dirt on the surface although ~3mm doesn't make much difference.

da_John_wee: grab a dremel and cutting disc and put a few "nicks" in those springs to tell you what they are. Its much better than losing those stickers. I put 1 mark on 10.5, 2 on 12.5, 3 on 15 and so on...
thats a great Idea! I alway vise press those damn stickers! they still comes off!, TY. I'm going to mentioned this on my blog credited to your ID.

I like that idea keeping diff in high position to keep the dirts away, you know I always run my car front 0.3-0.5mm lower to save a battery, It's like my car is always rolling on down hills, it saves some juice.
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Old 08-29-2009, 08:36 PM
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I plan on using a paint marker to ID my springs. Compress them fully then run a stripe of paint down one side.
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