Team Losi JRXS Type-R
#8506
Tech Addict
iTrader: (8)
Have an odd setup issue that I think I have figured out but just checking for some other feedback...
I last raced my Type R at the USVTA Nationals. Carpet track using the HPI tires and inserts and all. Anyways my car worked really well for the first 2-3 minutes. It was fast, smooth, basically a monkey car. The last 2-minutes or so the rear end would get looser and looser to the point the car was un-driveable. To this point I had thought of a few possibilities:
1) The front tires were taking that long to come up to temp
2) The rear tires were getting overheated by that point
3) There was air in the shocks and it was taking that long to affect the handling
4) The tires were picking up crap from the track, causing a build-up problem.
Going back to a conversation that I had with Billy Fischer back at the Horizon Hobby Shootout, I think I may have found the issue
5) The diff lube was breaking down and causing the diffs to overly diff-out.
I was using the brown Losi grease on the thrust bearings and the clear Losi stuff on the balls. I just rebuilt the diffs with AE Stealth and Black grease on the balls and on the thrust assembly. I also replaced the thrust washer assembly by tossing the thrust cages and using a total of 8-thrust balls on each diff in lieu of the standard 6. I won't be able to test this till Sunday, but I ran the exact same tires/tire dope on a different chassis 2-weeks ago and it never happened. It's not a tire deal, it's gotta be a chassis/setup deal. Any thoughts?
OH, and me sucking as a driver IS a valid explanation too
I last raced my Type R at the USVTA Nationals. Carpet track using the HPI tires and inserts and all. Anyways my car worked really well for the first 2-3 minutes. It was fast, smooth, basically a monkey car. The last 2-minutes or so the rear end would get looser and looser to the point the car was un-driveable. To this point I had thought of a few possibilities:
1) The front tires were taking that long to come up to temp
2) The rear tires were getting overheated by that point
3) There was air in the shocks and it was taking that long to affect the handling
4) The tires were picking up crap from the track, causing a build-up problem.
Going back to a conversation that I had with Billy Fischer back at the Horizon Hobby Shootout, I think I may have found the issue
5) The diff lube was breaking down and causing the diffs to overly diff-out.
I was using the brown Losi grease on the thrust bearings and the clear Losi stuff on the balls. I just rebuilt the diffs with AE Stealth and Black grease on the balls and on the thrust assembly. I also replaced the thrust washer assembly by tossing the thrust cages and using a total of 8-thrust balls on each diff in lieu of the standard 6. I won't be able to test this till Sunday, but I ran the exact same tires/tire dope on a different chassis 2-weeks ago and it never happened. It's not a tire deal, it's gotta be a chassis/setup deal. Any thoughts?
OH, and me sucking as a driver IS a valid explanation too
Let us know what happens.
RedRocket
#8507
Tech Champion
iTrader: (3)
Definately break in the diff after a rebuild, clean the tires really really well and apply something like jack the gripper to them afterwords (a major help for me when combating buildup with jaco blues at my local track), perhaps take some weight off of the front, such as stiffer spring, more front downtravle, etc.
I have never ran with hpi vintage tires though, so it seems as if it may be a tire issue.
I have never ran with hpi vintage tires though, so it seems as if it may be a tire issue.
This can happen, but not usually with the losi brown, You can use this on the diff balls as well. One question? What motor are you running? Usually this only happens with mod of maybe a 10.5. The diff may have just not been tight enough too. It felt good when it was cold on the bench, but was just loose enough that when you get going on the track it than heats up and slips.
Let us know what happens.
RedRocket
Let us know what happens.
RedRocket
#8509
Tech Champion
iTrader: (3)
I might as well post my setup, see if anyone spots anything....
Front:
5.5mm ride height
4-degree caster
0 arm sweep
Standard Ball Stud (No JR Link)
Long arm
Diff
45wt oil
#57 Piston
20lb spring
#1 hole in steering rack, #1 in steering arm
.050 sway bar
Shock in hole #2 on tower
Diff High
Arms centered
High Roll Center
Rear-
5.5mm ride height
2 1/2 degrees rear toe (3 degrees inboard but 1/2 hubs installed R on L and L on R)
Low roll center
Arms spaced to the rear
Camber Link- 5/A
35wt Oil
#55 piston
12.5 spring
Shock mounted in 3/outside
Diff High
Setup changes between then and now:
Before ran a 17.5 Brushless w/4-cell placed in the middle. Now running 21.5 with LiPo. Car is equipped with the Steel LiPo tray.
Front:
5.5mm ride height
4-degree caster
0 arm sweep
Standard Ball Stud (No JR Link)
Long arm
Diff
45wt oil
#57 Piston
20lb spring
#1 hole in steering rack, #1 in steering arm
.050 sway bar
Shock in hole #2 on tower
Diff High
Arms centered
High Roll Center
Rear-
5.5mm ride height
2 1/2 degrees rear toe (3 degrees inboard but 1/2 hubs installed R on L and L on R)
Low roll center
Arms spaced to the rear
Camber Link- 5/A
35wt Oil
#55 piston
12.5 spring
Shock mounted in 3/outside
Diff High
Setup changes between then and now:
Before ran a 17.5 Brushless w/4-cell placed in the middle. Now running 21.5 with LiPo. Car is equipped with the Steel LiPo tray.
#8511
Tech Elite
iTrader: (24)
I might as well post my setup, see if anyone spots anything....
Front:
5.5mm ride height
4-degree caster
0 arm sweep
Standard Ball Stud (No JR Link)
Long arm
Diff
45wt oil
#57 Piston
20lb spring
#1 hole in steering rack, #1 in steering arm
.050 sway bar
Shock in hole #2 on tower
Diff High
Arms centered
High Roll Center
Rear-
5.5mm ride height
2 1/2 degrees rear toe (3 degrees inboard but 1/2 hubs installed R on L and L on R)
Low roll center
Arms spaced to the rear
Camber Link- 5/A
35wt Oil
#55 piston
12.5 spring
Shock mounted in 3/outside
Diff High
Setup changes between then and now:
Before ran a 17.5 Brushless w/4-cell placed in the middle. Now running 21.5 with LiPo. Car is equipped with the Steel LiPo tray.
Front:
5.5mm ride height
4-degree caster
0 arm sweep
Standard Ball Stud (No JR Link)
Long arm
Diff
45wt oil
#57 Piston
20lb spring
#1 hole in steering rack, #1 in steering arm
.050 sway bar
Shock in hole #2 on tower
Diff High
Arms centered
High Roll Center
Rear-
5.5mm ride height
2 1/2 degrees rear toe (3 degrees inboard but 1/2 hubs installed R on L and L on R)
Low roll center
Arms spaced to the rear
Camber Link- 5/A
35wt Oil
#55 piston
12.5 spring
Shock mounted in 3/outside
Diff High
Setup changes between then and now:
Before ran a 17.5 Brushless w/4-cell placed in the middle. Now running 21.5 with LiPo. Car is equipped with the Steel LiPo tray.
Looks to me like your rear end is too soft. Go up to 56 pistons, 40 wt and 15-17.5 lb springs see if that works. The rear end of the car might be rolling too much and breaking traction.
#8514
Tech Addict
iTrader: (1)
I know its sound weird, but yesterday, my tires were squeeling. I had 17 front and 15 rear springs. I went to 15F/12R and my car became loose after about 2 minutes. I had the impression that softer springs would give me more overall traction but apparently not. I went back to my stiffer setup and the car was good for the entire race. The squeeling went away once the track got hotter.
#8515
Tech Champion
iTrader: (3)
I know its sound weird, but yesterday, my tires were squeeling. I had 17 front and 15 rear springs. I went to 15F/12R and my car became loose after about 2 minutes. I had the impression that softer springs would give me more overall traction but apparently not. I went back to my stiffer setup and the car was good for the entire race. The squeeling went away once the track got hotter.
#8516
This setup was awesome for vta, give it a try Gary
#8517
I know its sound weird, but yesterday, my tires were squeeling. I had 17 front and 15 rear springs. I went to 15F/12R and my car became loose after about 2 minutes. I had the impression that softer springs would give me more overall traction but apparently not. I went back to my stiffer setup and the car was good for the entire race. The squeeling went away once the track got hotter.
#8519
Tech Champion
iTrader: (3)
Will do. Setup looks close to Matt's setup he gave me when he ran 13.5 @ the Plex. Only question is that this is for a high-bite track. Where I run is relatively low-bite. I figure at most maybe just drop a spring rate and 2 1/2-5 on the shock oil to increase bite?
How does the Trinity oil compare to Losi?
Are you running the JR link or no?
How does the Trinity oil compare to Losi?
Are you running the JR link or no?