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Old 12-21-2015, 08:03 AM   #17326
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Iíve been chasing a setup issue in my car and I canít seem to get it straightened out. Itís a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. Iíve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 Iím running on a tight dirt indoor track, low to medium grip. Whatís happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I havenít been able to get it where I think it should be. Iíve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. Iím running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but itís very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And Iím talking very light throttle. Iím thinking about setting it back to stock and starting over. Iím also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
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Old 12-21-2015, 08:09 AM   #17327
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Im still learning, but how is your diff setup? Ball/gear? Tight/Loose?
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Old 12-21-2015, 08:20 AM   #17328
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Im still learning, but how is your diff setup? Ball/gear? Tight/Loose?
ball diff, a little on the loose side.
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Old 12-21-2015, 08:23 AM   #17329
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Originally Posted by greener74 View Post
Iíve been chasing a setup issue in my car and I canít seem to get it straightened out. Itís a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. Iíve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 Iím running on a tight dirt indoor track, low to medium grip. Whatís happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I havenít been able to get it where I think it should be. Iíve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. Iím running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but itís very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And Iím talking very light throttle. Iím thinking about setting it back to stock and starting over. Iím also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
Try something like 72/27-28.

your at final ratio of 6.93Fdr

what you have is 78/19
final ratio of 10.67 FDR WAY TO MUCH BOTTOM sir.

that is why you are kicking out when you getting on the gas

you are geared wrong sir
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Old 12-21-2015, 08:29 AM   #17330
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Old 06-08-2013, 08:51 PM #7174
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Default 13.5 gearing
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Originally Posted by skengines View Post
What gearing are you guys running for 13.5?
At WCRC, I run 72/29 with no boost/timing in the ESC, max timing on my motors end-bell. FDR is 6.45, plenty of hit bottom thru top.
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Old 12-21-2015, 08:45 AM   #17331
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Top shock position outside...

From what youve said thats your #1 enemy. Use 1.6 flats all around 32/30 AE oils; lay the rear shock all in at tower.

This will get you off the corner.

Now remove the 14g ; use alum D, brass C & run 1(maybe 2) thin pads behind the battery.

24mm ride ht all around.

Make sure your main rear wing is mounted as far forward as it can be.








Quote:
Originally Posted by greener74 View Post
Iíve been chasing a setup issue in my car and I canít seem to get it straightened out. Itís a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. Iíve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 Iím running on a tight dirt indoor track, low to medium grip. Whatís happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I havenít been able to get it where I think it should be. Iíve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. Iím running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but itís very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And Iím talking very light throttle. Iím thinking about setting it back to stock and starting over. Iím also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
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Old 12-21-2015, 08:55 AM   #17332
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Originally Posted by Motorman007 View Post
Try something like 72/27-28.

your at final ratio of 6.93Fdr

what you have is 78/19
final ratio of 10.67 FDR WAY TO MUCH BOTTOM sir.

that is why you are kicking out when you getting on the gas

you are geared wrong sir
I run a 13.5 as well, I am geared 72/32 and can run a full pack and motor will come off the track @ 130/140 degs. I run on a med size med grip clay track.

Been thinking of trying a 69T spur........
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Old 12-21-2015, 08:56 AM   #17333
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Quote:
Originally Posted by greener74 View Post
Iíve been chasing a setup issue in my car and I canít seem to get it straightened out. Itís a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. Iíve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 Iím running on a tight dirt indoor track, low to medium grip. Whatís happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I havenít been able to get it where I think it should be. Iíve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. Iím running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but itís very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And Iím talking very light throttle. Iím thinking about setting it back to stock and starting over. Iím also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
I have the same issues sometimes. Here are some suggestions:
1. I would first say get rid of all the rear weight. Some of the exit issue could be rotation momentum. Add it back slowly if it seems to benefit.
2. I run stock setup with the following mods: 3.5 degree rear toe, green springs, rear top on inside, and rear hubs forward with B5R arms.
3. Search for Razathorn and roll center to understand the impact of the rear camber inner link height. A lower rear inner link (higher roll center) will provide more traction on exit.
4. Take stock of your front tire condition. Too much front traction (worn foams, softer compounds, aggressive tread) can pull the balance away from the rear. Same if rears have lost their "edge"
5. A softer spring in the rear (i.e. white front / green rear) can reduce the loose tail, but at the expense of steering.

It doesn't take much to upset the F/R balance. Same track, same surface, but I forgot my traction sauce the other night on the local indoor clay track. Turned a great battery forward setup, to an undriveable loose tail. Had to do everything above to compensate!
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Old 12-21-2015, 10:06 AM   #17334
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Quote:
Originally Posted by greener74 View Post
I’ve been chasing a setup issue in my car and I can’t seem to get it straightened out. It’s a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. I’ve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 I’m running on a tight dirt indoor track, low to medium grip. What’s happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I haven’t been able to get it where I think it should be. I’ve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. I’m running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but it’s very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And I’m talking very light throttle. I’m thinking about setting it back to stock and starting over. I’m also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
That seems like the gearing is a little steep. I'd put the esc in blinky and start your gearing at 30/75 and go from there. There are a lot of other things that you could try......what oil & springs? How much droop?

I also think that one of the other posters has misinterpreted roll center. Roll center is all about the angle of the link. In most cases if you lower the inside you'd be lowering the roll center by reducing the angle of the rear link. we can argue about it all day but roll center is really all about the link angle....a longer link, more roll, reduces the angle of the link....more traction longer link. Less traction, shorter link, typically steeper link angle, higher roll center. Maybe I have it backwards, but I doubt it, regardless....I'm willing put myself out there for everyone to criticize.
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Last edited by QDRHRSE; 12-21-2015 at 10:45 AM.
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Old 12-21-2015, 10:50 AM   #17335
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Other thoughts:

I think -2 rear camber is a little too much, and also check your rear tire/foams. On some tire/foam/wheel combinations, I've had the foams be too hard/thick, pushing out the tire into a convex rounded profile which was impossible to put the power down.
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Old 12-21-2015, 11:21 AM   #17336
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Originally Posted by greener74 View Post
Iíve been chasing a setup issue in my car and I canít seem to get it straightened out. Itís a B5M with a 4 gear trans. Weighs 1645 with 62% in the rear. Both C and D brass blocks with an additional 14g on the bottom of the rear tower. White springs all around with 27.5 oil (kit pistons) blockade tires with worn out white foams. Top shock position outside. -1.5\-2 camber. Transverse battery all the way back. Iíve experimented with hub position (front and back) camber rod length (long and short) with shims 0 to 3mm, kick angles and toe settings 3+1 and 3.5+2 Iím running on a tight dirt indoor track, low to medium grip. Whatís happening is every time I exit a corner and give even the slightest amount of throttle the back end snaps out on me. Tire choice seems to help a little but I havenít been able to get it where I think it should be. Iíve driven other mid motor cars on the same track, (yokomo/Losi) and they seem to be fine. Iím running a 13.5 motor geared at 78/19 with added ESC timing, no boost, and -10% throttle expo. I thought it might have been my motor, esc, and gearing choices but itís very smooth and linear. And the car is good at speed, but corner exit on throttle is a handful. And Iím talking very light throttle. Iím thinking about setting it back to stock and starting over. Iím also going to go check to see if I can find a low grip setup somewhere and give it a try. Any suggestions would be appreciated.
Check all your bearings. Had a similar issue where my car was undrivable then went through all the bearings and found one side of my car had gritty bearings. Replaced them and car was back to normal. Then check your diff making sure it's tight.
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Old 12-21-2015, 12:27 PM   #17337
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Thank you everyone for all the great ideas. Switching to blinky mode and changing gearing was #1 on my list. My front tires are pretty aggressive. I think I have my rear hubs forward. Long camber links with 2mm inside washers. I will be 2 weeks before I can practice again. I'll see how it goes.
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Old 12-21-2015, 02:16 PM   #17338
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If traction is low you are going to want a shorter rear link, not longer.
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Old 12-21-2015, 02:49 PM   #17339
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If traction is low you are going to want a shorter rear link, not longer.
I've tried it both ways, but I probably have such a combination of things going on, I will have to look at it again. I think I may go to kit setup, then try the things that have been suggested.
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Old 12-21-2015, 04:02 PM   #17340
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anyone run one of the raptor bodies?

http://wildebeestdesigns.com/bfgrc/i...&products_id=3
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