Schumacher Corner
07-10-2007, 05:54 PM
No more desk job either so no more rctech during business hours
07-10-2007, 06:01 PM
see ya at the track
07-10-2007, 06:06 PM
07-10-2007, 06:30 PM
07-10-2007, 07:22 PM
*WARNING*: I am totally obsessive compulsive about getting my car to look and work PERFECT.
As far as I have discovered here are the best options for an Mi3 with the kit chassis and top deck and a 9550. Ill get pics up in a bit.
A. Use the kit servo saver. Its a pain to get together but it retains the intended geometry. I just switched my car over to this to try, but I have not driven the car with this setup yet, so durability/centering accuracy may be a problem according to some. It does fit and clear everything here on the bench.
B. Use the solid plastic servo horn included in the kit. Again, this retains the kits intended geometry and clears everything just fine. My only qualm with this solution is for people who drive less than perfect. While the servo is strong enough to withstand the abuse of no servo saver, I found that the splines on the servo horn would flatten and strip causing the car to develop a severe tracking problem. We have about 4 drivers here in my area with Mi3's and although some of them are not sure I am right (the better drviers who hit les stuff say the horn doesn't skip, but that makes sense to me. Since they're not hiting stuff as much, it has just taken them longer to develop the problem)I am pretty certain we have all experienced the servo horn skipping teeth.
C. Use a 201 Kimbrough servo saver. The saver fits without any modifications, but is not the same length as the kit saver (its shorter) so you may notice a less agressive steering feel, similar to using a shorter track rod. I was able to use both the center and the slightly higher outside holes with this servo saver. This is the option I have had the most success with. I went to this after using the kit plastic servo horn and it solved my tracking issues. I have tested it quite a bit and have found no down side other than it is a bit shorter than the kit was intended for.
D. YANG STYLE
Use the large APS (very similar to the large kimbrough) on the servo. Dremel out a slot in the chassis under your servo horn to allow fitment. I did not check with calipers or anything and have not run this option, but it appears to give kit geometry with the benefit of the servo saver. The bonus is it comes in pretty purple for the likes of Randy Caster.
I have been thinking WAY too hard about servo's, and steering geometry and track rod lengths, and exponential etc. (You should see the two full pages I have with little circles and hash marks and measurements used to model the Mi3's steering geometry for all the differences explained here as well as various trackrods, post mountings and other variables. I got in a "I want to figure this WHOLE thing out" mood after stupid seaball got me thinking about all this physics stuf lol. I posted my general findings** below if any one's interested) I have played with raising the servo using shims to clear the large servo savers (doesn't work) and shimming the servo out to get clearance. The information above is assuming kit standards unless otherwise stated. I say this because I have also been known to raise my bellcrank post mount 3 mm to clear my LiPo with the longest (kit) track rod. That's just a whole 'nother can-o-worms though.
Findings**
Track Rod Width
-Wider = more ackerman = more toe-in as you turn
-Narrower = less ackerman = more toe-out as you turn
Track Rod Length
-Longer = faster wheel movement and more wheel movement
-Shorter = slower wheel movement abd less wheel movement
-Determines how much of the radio's wheel travel is needed to effect lock to
lock on the car.
-Similar feel to changing servo horn length
Track Rod Post Mount
-Forward = Twitchier/More responsive around the endpoints and more wheel
movement
-Back = Twitchier/More responsive around center and less wheel movement
-Similar to radio exponential
As far as I have discovered here are the best options for an Mi3 with the kit chassis and top deck and a 9550. Ill get pics up in a bit.
A. Use the kit servo saver. Its a pain to get together but it retains the intended geometry. I just switched my car over to this to try, but I have not driven the car with this setup yet, so durability/centering accuracy may be a problem according to some. It does fit and clear everything here on the bench.
B. Use the solid plastic servo horn included in the kit. Again, this retains the kits intended geometry and clears everything just fine. My only qualm with this solution is for people who drive less than perfect. While the servo is strong enough to withstand the abuse of no servo saver, I found that the splines on the servo horn would flatten and strip causing the car to develop a severe tracking problem. We have about 4 drivers here in my area with Mi3's and although some of them are not sure I am right (the better drviers who hit les stuff say the horn doesn't skip, but that makes sense to me. Since they're not hiting stuff as much, it has just taken them longer to develop the problem)I am pretty certain we have all experienced the servo horn skipping teeth.
C. Use a 201 Kimbrough servo saver. The saver fits without any modifications, but is not the same length as the kit saver (its shorter) so you may notice a less agressive steering feel, similar to using a shorter track rod. I was able to use both the center and the slightly higher outside holes with this servo saver. This is the option I have had the most success with. I went to this after using the kit plastic servo horn and it solved my tracking issues. I have tested it quite a bit and have found no down side other than it is a bit shorter than the kit was intended for.
D. YANG STYLE
Use the large APS (very similar to the large kimbrough) on the servo. Dremel out a slot in the chassis under your servo horn to allow fitment. I did not check with calipers or anything and have not run this option, but it appears to give kit geometry with the benefit of the servo saver. The bonus is it comes in pretty purple for the likes of Randy Caster.
I have been thinking WAY too hard about servo's, and steering geometry and track rod lengths, and exponential etc. (You should see the two full pages I have with little circles and hash marks and measurements used to model the Mi3's steering geometry for all the differences explained here as well as various trackrods, post mountings and other variables. I got in a "I want to figure this WHOLE thing out" mood after stupid seaball got me thinking about all this physics stuf lol. I posted my general findings** below if any one's interested) I have played with raising the servo using shims to clear the large servo savers (doesn't work) and shimming the servo out to get clearance. The information above is assuming kit standards unless otherwise stated. I say this because I have also been known to raise my bellcrank post mount 3 mm to clear my LiPo with the longest (kit) track rod. That's just a whole 'nother can-o-worms though.
Findings**
Track Rod Width
-Wider = more ackerman = more toe-in as you turn
-Narrower = less ackerman = more toe-out as you turn
Track Rod Length
-Longer = faster wheel movement and more wheel movement
-Shorter = slower wheel movement abd less wheel movement
-Determines how much of the radio's wheel travel is needed to effect lock to
lock on the car.
-Similar feel to changing servo horn length
Track Rod Post Mount
-Forward = Twitchier/More responsive around the endpoints and more wheel
movement
-Back = Twitchier/More responsive around center and less wheel movement
-Similar to radio exponential
07-10-2007, 08:53 PM
07-10-2007, 09:08 PM
07-10-2007, 09:58 PM
07-10-2007, 09:58 PM
07-10-2007, 10:35 PM
andrewdoherty-
Thanks for that info dude; great job
But for MY knowledge, what effect on the car (the toe-in/toe-out as you turn) does your findings have with track rod width?
Thanks for that info dude; great job
But for MY knowledge, what effect on the car (the toe-in/toe-out as you turn) does your findings have with track rod width?
07-10-2007, 11:29 PM
Paul thanks alot for all the help that you have given me over the last year or s i have been running schumacher u have been such a great help from set up help to coming to work on your day off just to help me build my mi3 to perfection........Im extremely sad to her that ur leaving but best of luck on ur next job im sure who ever you go work for is very lucky to have such a knowlegible person like ur self....BYW where are you going
07-11-2007, 12:32 AM
Tech Master
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Join Date: Sep 2005
Location: The Apocalypse suburb of Robina
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G,day,
Have you blokes got any tips for the Mi2 in regards to setups and gearing?
Currently running 27turn stock here in Oz.
Cheer's.
Have you blokes got any tips for the Mi2 in regards to setups and gearing?
Currently running 27turn stock here in Oz.
Cheer's.
07-11-2007, 03:11 AM
I gotta be honest here . . .all of my "findings" were based on paper/pencil/protractor/compass calculations. I have yet to recieve my track rod set to test what I think you're asking. But here's my thoughts anyway. If anyone else has more credible info please share
More ackerman increases steering mid corner (at the apex when the wheels are turned the most, the ackerman effect is at its greatest). You can go too far though and end up dragging your inside front wheel too, which could cause some serious rotation inducing a snap spinout?
Less ackerman reduces steering mid corner.
Your steering feel at corner entry and exit will not be affected by ackerman and is reliant upon your static toe settings, springs, oil, caster, etc.
In short I'd say it would be useful to use less ackerman if you're oversteering mid corner and to use more ackerman if you're pushing mid corner.
Somewhere in there too there's a discussion on how corner speed is affected by ackerman. You definitely need a difference in wheel angles to roll through a corner without binding, but you could obviously have too much or too little ackerman for a given corner which would theoretically slow you down.
My .02
More ackerman increases steering mid corner (at the apex when the wheels are turned the most, the ackerman effect is at its greatest). You can go too far though and end up dragging your inside front wheel too, which could cause some serious rotation inducing a snap spinout?
Less ackerman reduces steering mid corner.
Your steering feel at corner entry and exit will not be affected by ackerman and is reliant upon your static toe settings, springs, oil, caster, etc.
In short I'd say it would be useful to use less ackerman if you're oversteering mid corner and to use more ackerman if you're pushing mid corner.
Somewhere in there too there's a discussion on how corner speed is affected by ackerman. You definitely need a difference in wheel angles to roll through a corner without binding, but you could obviously have too much or too little ackerman for a given corner which would theoretically slow you down.
My .02
07-11-2007, 03:44 AM
I thought about i a bit more and also thought I'd mention that ackerman is less noticeable or usefull in highspeed turns as the outside wheel is carrying the majority of the weight, while the inside wheel becomes "light". In high speed turns the turning attitude is mostly determined by the outside wheel. In highspeed turns you are also using a relatively small amount of steering, furhter reducing whether you'll feel the ackerman or not.
However in slow, tight corners ackerman will be more noticeable.
Sooo . . .theoretically you will notice the differences between track rods at the apex of the slower and tighter corners of the track. At corner entry, exit, and in high speed corners you won't feel much of a difference.
Wider Track Rod = Tighter turning radius (more steering) at the apex (as compared to corner entry and exit) of slow corners.
Narrower Track Rod = Larger turning radius (less steering) at the apex (as compared to corner entry and exit) of slow corners.
Again I emphasize THEORETICALY. I have not tried any of the different track rods. This is pure speculation on my part. If you know bettter than me please share
However in slow, tight corners ackerman will be more noticeable.
Sooo . . .theoretically you will notice the differences between track rods at the apex of the slower and tighter corners of the track. At corner entry, exit, and in high speed corners you won't feel much of a difference.
Wider Track Rod = Tighter turning radius (more steering) at the apex (as compared to corner entry and exit) of slow corners.
Narrower Track Rod = Larger turning radius (less steering) at the apex (as compared to corner entry and exit) of slow corners.
Again I emphasize THEORETICALY. I have not tried any of the different track rods. This is pure speculation on my part. If you know bettter than me please share
07-11-2007, 10:36 AM
I thought about i a bit more and also thought I'd mention that ackerman is less noticeable or usefull in highspeed turns as the outside wheel is carrying the majority of the weight, while the inside wheel becomes "light". In high speed turns the turning attitude is mostly determined by the outside wheel. In highspeed turns you are also using a relatively small amount of steering, furhter reducing whether you'll feel the ackerman or not.
However in slow, tight corners ackerman will be more noticeable.
Sooo . . .theoretically you will notice the differences between track rods at the apex of the slower and tighter corners of the track. At corner entry, exit, and in high speed corners you won't feel much of a difference.
Wider Track Rod = Tighter turning radius (more steering) at the apex (as compared to corner entry and exit) of slow corners.
Narrower Track Rod = Larger turning radius (less steering) at the apex (as compared to corner entry and exit) of slow corners.
Again I emphasize THEORETICALY. I have not tried any of the different track rods. This is pure speculation on my part. If you know bettter than me please share
However in slow, tight corners ackerman will be more noticeable.
Sooo . . .theoretically you will notice the differences between track rods at the apex of the slower and tighter corners of the track. At corner entry, exit, and in high speed corners you won't feel much of a difference.
Wider Track Rod = Tighter turning radius (more steering) at the apex (as compared to corner entry and exit) of slow corners.
Narrower Track Rod = Larger turning radius (less steering) at the apex (as compared to corner entry and exit) of slow corners.
Again I emphasize THEORETICALY. I have not tried any of the different track rods. This is pure speculation on my part. If you know bettter than me please share
