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Old 05-21-2009, 06:19 AM
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Originally Posted by Dragonfire View Post
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.
I just rebuilt my diffs with a thrust bearing Schreffler and Fairtrace reccomended, they are smooth as a baby's butt now . I'm tempted to do the d-ring mod on the diff tube as well to loosen up the rear diff.
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Old 05-21-2009, 06:21 AM
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Originally Posted by Jaz406 View Post
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.

Hmm you may be onto something with the tires!! I'll have to try the toe as well I'll let you know how it works out for me this weekend.
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Old 05-21-2009, 09:20 AM
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Most likely the bulk of your problem is tire, start with some sorex32s and tire warmers. You could try 28s but they will probably overheat. On the chassis front start with both roll centers & diffs in the high position and go from there.
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Old 05-21-2009, 10:50 AM
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Originally Posted by mtveten View Post
Most likely the bulk of your problem is tire, start with some sorex32s and tire warmers. You could try 28s but they will probably overheat. On the chassis front start with both roll centers & diffs in the high position and go from there.
What does the the high roll center do for the car? Does it make the car roll more easily or make it corner flatter?

Oh and it's not just for me ... my 10 year old son is now running a type-r and the little bugger keeps asking me "why are you changing this or that" and honestly i don't have good answers for him most of the time . It's just what i see the faster racers do so i do it too.
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Old 05-21-2009, 03:45 PM
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Originally Posted by YmeBP View Post
What does the the high roll center do for the car? Does it make the car roll more easily or make it corner flatter?

Oh and it's not just for me ... my 10 year old son is now running a type-r and the little bugger keeps asking me "why are you changing this or that" and honestly i don't have good answers for him most of the time . It's just what i see the faster racers do so i do it too.
Best way I can explain it is roll center affects the angle the force is applied to the tires contact patch. Too low (small angle) the tires will not grip and just "slide". I notice roll center changes more in 180* corners than anywhere else. Get the roll center right and you'll be amazed at the speed you can carry through them.

Sway bars are what help the car corner "flatter" and limit lateral movement without hurting front to rear weight transfer/traction.


Tires are the first choice of getting traction unless "spec".
Camber adjustments
Roll center adjustments,
Droop settings
Camber link position and camber gain shims on the outer hubs and steering blocks.
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Old 05-21-2009, 04:38 PM
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Originally Posted by Jaz406 View Post
Best way I can explain it is roll center affects the angle the force is applied to the tires contact patch. Too low (small angle) the tires will not grip and just "slide". I notice roll center changes more in 180* corners than anywhere else. Get the roll center right and you'll be amazed at the speed you can carry through them.

Sway bars are what help the car corner "flatter" and limit lateral movement without hurting front to rear weight transfer/traction.


Tires are the first choice of getting traction unless "spec".
Camber adjustments
Roll center adjustments,
Droop settings
Camber link position and camber gain shims on the outer hubs and steering blocks.
Perfect thank you!!
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Old 05-21-2009, 05:30 PM
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Originally Posted by YmeBP View Post
I just rebuilt my diffs with a thrust bearing Schreffler and Fairtrace reccomended, they are smooth as a baby's butt now . I'm tempted to do the d-ring mod on the diff tube as well to loosen up the rear diff.

what is that D ring mod? slot round side of hub to fit another D shaped diff ring?
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Old 05-21-2009, 06:00 PM
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Originally Posted by da_John_wee View Post
what is that D ring mod? slot round side of hub to fit another D shaped diff ring?
Pretty much, but the d-ring replaces the brass and steel slipper "shims". ( i think, i've never done it)
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Old 05-21-2009, 06:08 PM
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Originally Posted by da_John_wee View Post
what is that D ring mod? slot round side of hub to fit another D shaped diff ring?
Originally Posted by a_main_attendee View Post
Pretty much, but the d-ring replaces the brass and steel slipper "shims". ( i think, i've never done it)
Yes you slot the diff hub to accept the D ring. We found that this helped free the car up on carpet. It allows for a much freer diff. The only problem I've found with doing this is if the diff slips it pretty much ruins it and has to be rebuilt.
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Old 05-21-2009, 08:20 PM
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Originally Posted by YmeBP View Post
Perfect thank you!!
Except for the part where he didn't mention that a higher RC, for all the extra traction you get on the outside wheel, you lose about the same amount on the inside wheel.
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Old 05-21-2009, 10:24 PM
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Originally Posted by adamge View Post
Except for the part where he didn't mention that a higher RC, for all the extra traction you get on the outside wheel, you lose about the same amount on the inside wheel.
adamge:
Your exactly right that's why the right amount of hinge pin height is important if you read into the statement, changing the roll center (force angle) would move the force to the inside or outside of the contact patch of the tire. I'm just trying to be helpful and here's a link that explains more.

http://http://www.rc-truckncar-tuning.com/roll-center.html

Now if I could put these adjustments into my car at the right time I would be happy

Last edited by Jaz406; 05-21-2009 at 10:37 PM.
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Old 05-22-2009, 06:17 AM
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Originally Posted by Jaz406 View Post
adamge:
Your exactly right that's why the right amount of hinge pin height is important if you read into the statement, changing the roll center (force angle) would move the force to the inside or outside of the contact patch of the tire. I'm just trying to be helpful and here's a link that explains more.

http://http://www.rc-truckncar-tuning.com/roll-center.html

Now if I could put these adjustments into my car at the right time I would be happy

Even better thanks guys!!

HOLY CRAP!!! This site is the motherload of info!! It's even better than the xxx-main rc book!

Last edited by YmeBP; 05-22-2009 at 06:32 AM.
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Old 05-22-2009, 06:34 AM
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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.
Give it more front droop that will give you more on power stabiilty (and a bit less on power steering). Works every time
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Old 05-22-2009, 09:16 AM
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Here are some photo's of the completed production layshafts. I found a way to make them a little lighter by removing some pockets. I am very happy with the way they turned out

The guys racing at the Much More Masters tomorrow come and see me. Everyone who has sent me requests, I will have enough for you all from the first run.

Anyone in the US, I am sending some to a distributor, who you can buy directly from. This will to save you postage costs from Australia. I will let you know the details once the deal is finalized early next week.

I really appreciate the interest shown.
Attached Thumbnails Team Losi JRXS Type-R-layshaftcomplete.jpg   Team Losi JRXS Type-R-layshaftmachining5.jpg   Team Losi JRXS Type-R-layshaftmachining4.jpg  
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Old 05-22-2009, 10:42 AM
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Pablo, will the PRS spur gears fit?
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