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Schumacher Mi4

Old 10-09-2010, 04:43 PM
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Can the Mi4LP be upgraded to a Mi4CX with the parts of the new changes?
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Old 10-09-2010, 05:08 PM
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Originally Posted by YZFAndy View Post
* Black lightened T6 Aluminium Bulkheads front and rear.
Another time they stole a idea from our clan
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Old 10-10-2010, 12:54 AM
  #2253  
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Actually, we had black bulkheads before the Mi4 was released - just no one saw them

Wild man, yes, CX parts will fit LP.
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Old 10-13-2010, 04:23 PM
  #2254  
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Default Setup Q's

Ok so I'm running Kenny Lambert base rubber carpet setup, now the only changes I've made are Green on the front, and Blue on the rear. Now the car handles really well, very consistent lap times. However, I've noticed that the car will traction roll every so often and I can see it listing just slightly. Should I increase the oil wt... 35wt to 40 wt or should I add a thin sway bar on the front to reduce the front grip level... In addition the track layout is tight and twisty, but it does change from tight to open layouts every so often.

Give me some tips boys cause I like winning..:P

btw won every heat and tq and won the main.

Cheers

Edward Pickeirng.
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Old 10-13-2010, 05:16 PM
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I had the same issue last yr of traction rolling. Add more droop front and rear and change to a hard compound tire if you are using a soft tire. Those dont work get a thicker top deck
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Old 10-14-2010, 09:46 AM
  #2256  
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Originally Posted by EDWARD2003 View Post

Cheers

Edward Pickeirng.
A softer roll bar is a no. Roll bars take away grip and reduce roll/lean. So a thinner one will give you more roll/lean and grip, and more traction roll.

Sometimes softer springs can help in reducing traction roll as it removes some of the instant bite you get from a harder setup.

With loads of grip like that try around 45wt oil as this will stop the car transferring weight around too quickly. with high grip i've found this weight oil to be the best balance between direction change speed and the car tying itself in knots.

And reduce camber. This is a win win tweak as you remove some side grip, reducing the tendency to roll but you will gain in acceleration, braking and the inside of your tyres wont rib up as much.

Order i would go in is
1 : increase oil weight
2 : Reduce camber
3: Soften springs on the front.

If none of that works then look at raising roll centres but then you are changing the handling quite a bit. Also if the car is listing make sure everything is even and the car is balanced(weighted) left to right.

Originally Posted by jhock View Post
] Add more droop front and rear and change to a hard compound tire if you are using a soft tire.
I would have thought that would have caused more traction roll!! Do you mean give the droop a higher value on the gauges = less downward drop or give the car more droop meaning the wheels drop down more?
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Old 10-14-2010, 01:27 PM
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Not really Andy. When you run a higher number of droop(less droop) the car will roll to that point and stop, letting the inside tires come up. When you run a lower number droop(more droop) it lets the car roll more and allow the tires to stay in contact more. Eventually they will come off the ground depending on traction but you can dial out Dual rate if its cutting into the turn.
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Old 10-14-2010, 06:59 PM
  #2258  
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^^^ This is what I find confusing about the 2 ways droop is talked about. (But I do get it either way, just please clarify which way one is talking about it in ones post.) Most at the club here refer to more droop as the arms falling more. In offroad that's the way most think about it. Of course then less droop would be the arms lifted up more. So, when saying more droop would cure traction roll would be completely wrong with the thinking in this post.

With foam tires, many then talk about it the other way around, as it is thought about droop relative to ride height since the diameter of foam tires changes every run, also causing needed roll center changes.

Last edited by rezenclowd3; 10-14-2010 at 08:04 PM.
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Old 10-14-2010, 09:58 PM
  #2259  
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Uptravel is a slightly less ambiguous term. I've given up measuring droop on blocks, because every time I do, the car pulls and feels tweaked. So I just stick my ride height gauge under the centerline of the car, and push it in to raise the chassis, and then adjust the droop screws to where the tires just barely drag on the setup board. Seems to be more consistent for me.

I'm also having traction roll issues. The car has ridiculous grip and turns in so, so hard. I have to tip-toe around the track to keep it off its lid. But the car reacts very differently when you're below its cornering limits, and it makes it hard to drive consistently, and I keep nosing it into the board before the apex. I can't attack at all.

Last night, I ran more uptravel (3.5mm rear and about 3mm front) to try and make the car more consistent than last time on carpet. Last time out I was about 2.5mm rear and 1.5mm front.

I started the night with a white/white (14 lb/in) spring setup because my last race was on asphault, and I didn't get there early enough to tweak the setup before Q1. I blew my brand new litemodz CVS in the first session, doing 3 wheel drive for most of it. The car was extremely responsive in the front end, especially going into the high speed sweeper. But I decided to leave the setup alone for Q2, since I thought the hyper front end might have been from the blown CVS.

For Q2, the car was still very aggressive with a tendancy toward traction roll. For the B main, I threw on AE blue fronts (17.0 lb/in) and the Schui Blue rears (16.0). The car was even more responsive, a bit looser in the rear, and just as traction-roll-inclined, if not more due to the faster weight transfer.

My front camber links are nearly flat, and my rears are pretty inclined. The other guy at my pit table (DIALED) running JayBee's old Mi3.5 said it could be an unbalanced roll center issue.

Last time on carpet, with blue front and white rear, and less uptravel, the car was faster, but I still had trouble driving it consistently. And it was still traction-rolly.

So I guess next time out, I'm gonna go back to the blue/white spring setup, and mess with the camber links.

EDIT: I'm running -2.0 camber front and rear. I tried less last time out, and the car was definitely slower, so that's why I went back to the -2.0. Spec tires are Sweept QTS32 with Paragon. I tried barely saucing (just cleaned the tires with some sauce and wiped it and let it dry). Didn't seem to negatively impact grip. I'm running AE 50wt shock oil, but it's been a few weekends since I filled 'em. They still feel smooth, but not as stiff as when they were freshly filled, and I think one of the rears might be leaking a hair. I'll probably re-do the o-rings and put in fresh oil. I definitely like the car better with the heavier oil than I did with the 30-35wt range.

-Mike
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Old 10-14-2010, 10:06 PM
  #2260  
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Originally Posted by grippgoat View Post
Uptravel is a slightly less ambiguous term.
-Mike
The thing is, we do not have uptravel limiters on the Mi4. I know the Losi JRXS does, and my Team Magic G4S does, as well as many nitro 8th scale onroad cars...
(Unless of course you were generally just saying that "uptravel" is less ambiguous in which I would agree.)

If you car is pulling, something is wrong. If you have a hard time adjusting with droop blocks, you can try using something like the TC5 droop tool, which is IMO much easier to use. (not like droop blocks are hard...)
Check your bearings, left-right, front-rear and cross weight distribution, droop, camber, nothing bent, etc etc etc. Worn tires can also cause handling problems such as this....
Don't forget to check steering linkage play either. That seems to be a big one many miss IMO.
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Old 10-14-2010, 10:44 PM
  #2261  
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Originally Posted by rezenclowd3 View Post
The thing is, we do not have uptravel limiters on the Mi4. I know the Losi JRXS does, and my Team Magic G4S does, as well as many nitro 8th scale onroad cars...
(Unless of course you were generally just saying that "uptravel" is less ambiguous in which I would agree.)
Hrm. The meaning I've most commonly heard people use for uptravel is how far the chassis can move upwards before the tires lift up. That's the same thing as droop, which the droop screws limit. Does it also mean how much the wheel can travel upwards relative to the chassis? You could limit that with spacers on the shock shaft, or the idea I thought of was fuel tubing on the shock shaft. But I don't really see why you'd need to limit that.

Originally Posted by rezenclowd3 View Post
If you car is pulling, something is wrong. If you have a hard time adjusting with droop blocks, you can try using something like the TC5 droop tool, which is IMO much easier to use.

Check your bearings, left-right, front-rear and cross weight distribution, droop, camber, nothing bent, etc etc etc. Worn tires can also cause handling problems such as this....
I was just saying that when I use the blocks and get it spot on, it's not even with the other technique, and the car pulls. When I use the other technique, the car drives nice and straight. I'm pretty sure it's because my static weight distribution isn't very good. The battery side is heavy from the ProTek 5600. I do have corner scales I picked up cheap on ebay, but I only tried corner balancing once. Normally I measure ride height, and use my ride height gauge to check that the upper spring perch position is even side to side. When I corner balanced for 50% cross weights, the perches were actually pretty uneven side-to-side. It was probably placebo, but I think the car did feel better. Maybe I'll do that again if I have time. I ended up putting a weird rake in the car last time (5.5mm front, 5.0mm rear) so that may well have made more difference than the actual corner balancing.

Don't forget to check steering linkage play either. That seems to be a big one many miss IMO.
The stock steering seems to have a lot of play, even with a little spacer, but the dual-link seems pretty precise. My ball cups are starting to get a bit tired, but they don't seem to have enough play to worry about yet. I checked all the bearings last time out, after I blew one during warm-up for the main. They seem to spin freely, and the wheels don't wobble relative to the knuckles, except a bit on one of the fronts, but I think that's the knuckle getting worn as it did that with fresh bearings.

-Mike
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Old 10-14-2010, 10:55 PM
  #2262  
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Yes, uptravel is referring to the arms, not the chassis.

Also for steering linkage, don't forget that as your servo wears, you get gear backlash, where the servo itself is giving you unwanted slop. I get that as people tag me, or if I happen to hit something, due to not using a servo saver. Servo saver would be cheaper, but alas, I like to take that out of the equation.

When I set my car up, its weight distribution first, but make sure the shocks have equal pre-load, and do not use your tires, use setup wheels instead. Then I set droop, set the geometry, check tweak, set geometry again, and check tweak one last time. Now check weight distribution with tires on. If still off, start from the beginning of this paragraph again as overall much of the setup should be damn close.

Don't forget that when changing the geometry of something, you are changing the geometry of something else as well most of the time. For example, when changing the toe in or out, you also change camber, (due to your caster angle) so it takes a few back-and-forths setting things up.

Oh another tip, which I believe is in the manual, do not ream out the c-hubs or rear toe blocks to get free movement, but ream out the arms. I made this mistake on my second assembly going crazy with the reamer as it was 3am with a couple of beers and TV on :-( An expensive mistake now that my new Mi4LP has too much play with new parts...so now they are labeled "temp fix only" in my parts box....

Last edited by rezenclowd3; 10-14-2010 at 11:07 PM.
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Old 10-15-2010, 11:00 AM
  #2263  
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have a look here for pics of the new cx

forum.racing-cars.com/forum_posts.asp?TID=10687&
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Old 10-15-2010, 02:00 PM
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you have to remember that your track is designed and prepped to favor 1/12 scale cars. To me, the Traction Action that is being sprayed made my car very inconsistant. My schuie was always a roll monster on carpet when I first started running carpet with it, of course that was when the spec tire was a sorex 28, I had to CA the sidewalls to cure the rolling. the car works great on jaco blues, (on carpet) but now were back to a tire that has more traction then the blue. so a little CA may be your friend. heavy springs will only make it roll more. blue springs in the rear is to much. I also find mixing brands does work very well, shouie says its a 16.0 lb blue spring, but its not, its actually heavier then the 17.0lb ae blue spring.
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Old 10-16-2010, 01:38 AM
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Originally Posted by skypilot View Post
you have to remember that your track is designed and prepped to favor 1/12 scale cars. To me, the Traction Action that is being sprayed made my car very inconsistant. My schuie was always a roll monster on carpet when I first started running carpet with it, of course that was when the spec tire was a sorex 28, I had to CA the sidewalls to cure the rolling. the car works great on jaco blues, (on carpet) but now were back to a tire that has more traction then the blue. so a little CA may be your friend. heavy springs will only make it roll more. blue springs in the rear is to much. I also find mixing brands does work very well, shouie says its a 16.0 lb blue spring, but its not, its actually heavier then the 17.0lb ae blue spring.
Points taken. I'd rather avoid the CA route, mostly because I don't like dealign with CA.

Do you by any chance have a setup sheet with a full setup? You posted a bunch of settings in this thread back when I first got the car, and I will go back and look at those again.

Would shimming the track width out do anything to reduce traction roll?

-Mike
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