View Full Version : How to eliminate push?

2011.04.12, 05:25 AM
I always thought push was better than the rear end swinging around. Now I have too much push and trying to get the car to stick better and act more neutral. I have the softest red springs in the front of my MR-02 and a soft rear setup. Would new front tires help or stiffen the rear help my problem.

Front Red Springs
Short Cups
No spacers in front
Med T-plate
Atomic Top Shock
DDS with blue springs on top and green on bottom.
Running a Mosler with a PN 33T (9/52)
K30 Radials in front
K20 Radials in rear

Or is the motor too fast causing the push. Car can chase down a Chili motor with a head start.

2011.04.12, 06:40 AM
I'm at a similar place right now. Previously i had problems with the tail going awol but now the car is just a bit too pushy to keep up in the tighter sections of track.

My setup is
-1.0 toe bar
1.5deg camber knuckles
Front white springs
Shortest cups w/ 1 spacer preload
Med T-plate
No topshock
DDS with blue/blue
F599xx with Pn70t (51/14)
K30 slick
K20 radial

What i'm going to try today is:
1) Try again with softer front springs. Previously i felt this only added to the turn-in pushing but made the car more stable overall (no more problems with bumps on the track)
2) More toe out, maybe 2.0
3) Stiffer t-plate
4) Loosening the diff. Just remembered i've been running a really tight diff so that might cause some turn-in push

As far as my understanding goes, all these *should* help the car turn tighter.

2011.04.12, 08:18 AM
Anything either of y'all mentioned should help.

A couple other things you can try are:
-Stiffer top shock spring, or bottom DDS spring (push more weight forward on power)
-Stiffer T/H-plate (lessen rear grip)
-Lower the front of the chassis or body (add down force to front end)
-If you are using a wing, remove or cut it down (lessen rear down force)

Depending on the grip levels of the track, it may come down to taking a different line, and not being on throttle so much. I find myself off throttle (or at least not full bore) a lot more than most people, but I am usually competitive. Being easier on the throttle makes it easier for me to hit my lines tighter, and more consistent, which allows me to keep carry speed up and not scrub as much as others may. It's a little more passive approach, but consistency is the key at most mini-Z races I attend.

Chicken Little
2011.04.12, 09:56 AM
Have you tried shaving down your Mosler body? I had the same problem until the guys I race with who use the Mosler told me to shave it down. I also have a very similar set-up as you but I use the PN double A arm suspension.

2011.04.12, 10:02 AM
Have you guys tried using softer tires in the front?

I read you're using K30 slicks and radials. Try 20's. Or some other Atm o Pn type.

Most of the time, just changin' tires makes a HUGE difference.

2011.04.12, 10:09 AM
Since this is an MR02, do you have Virtual Inertia disabled? With it enabled, even when you back out of throttle, the car will still have a little forward drive, which will lead to a little push. In general the 33t has less drag brake than a lot of other motors, which will also lead to a little push as you get out of throttle entering a corner.

Where does the car have push? Does the car push off throttle, on throttle or both? I typically find 30d radial to have a little more grip than I would like at Action... So I wouldnt think the tires would be the culprit. Check your ride height, make sure that the front of the body does not bottom out. You may need to shave a little off the bottom. I removed almost 2mm from my Mosler to get clearance that I was comfortable with.

I like a little push in my car. I find it easier to overdrive a car with a little push than to underdrive a car that has oversteer.

I would also recommend trying a stiffer front spring. It sounds funny, but the red spring will take steering away after turn in, going to green or white should give you a little more mid/exit steering.

You can also try swapping the DDS springs so the blue is on bottom, green on top (blue is harder from what I remember), this should give a little more steering, primarily on throttle.

Diff tension; if your diff is tight, you will have a little less steering off throttle, but should get a little oversteer on throttle. With a loose diff, you will have more steering into the corner, but not have as much drive and push more out of the corner. I typically run my diff on the tight side.

Mike Keely
2011.04.12, 11:24 AM
The K30 slicks are the tire I go to when I have to much front traction. If I have the K30's on and need more front steering I go to PN 8 slicks or the PN 15X patern fronts and true the X down so it is a slick tire.

You can also try changing the width of the car. If you are running +2 front rims and go down to a +1 front rim you can get more steering with the same tire compound.

Chicken Little
2011.04.12, 11:42 AM
EMU has good advice. He was the one who told me to change my ride height and tune my chassis by switching springs around for the right set-up. My Mosler was putting in good lap times. If only I could stay consistent. That's the best part about racing with a sponsored driver as knowledgeable as Eugene. Thanks buddy!

EMU, I switched my Mosler to the 599XX and I was able to get a 9.5 on Ron's recent track set-up! This body is amazing! :D

2011.04.12, 11:00 PM
Most of the time, just changin' tires makes a HUGE difference.

i'm with leonen 100%... tires after all... are #1 priority... then you can fine tune handling with all the other stuff... next i would consider adding camber to the knuckles... but that's just me... hope this helps... :D

2011.04.13, 12:28 AM
i'm with leonen 100%... tires after all... are #1 priority... then you can fine tune handling with all the other stuff... next i would consider adding camber to the knuckles... but that's just me... hope this helps... :D

I feel that a lot of times, changing tires are the best option for a quick fix. However, I also feel that many times changing tires just masks the underlying issue you are trying to get rid of. In this case push. The 30d radial front tire has plenty of bite on all of the local NY tracks, sometimes too much. What would you switch to, 20d? Then you will struggle for rear grip as you apply power. I personally feel that the 30d radial has a little too much grip for many of the local tracks, and usually use a tire with a little less grip; PN x15, or ATM 40d slick-R.

I feel that when I use the 30d radial a lot of the time I have less speed in the corners, compared to the x15 or 40d slick-R. I have to stay on throttle more, and the car loses speed in the corners since it slows down.

Granted, people drive and setup their cars differently, so one setup may require more grip from the tires than others... But I feel that if the 30d radial is pushing, there is something else in the setup that is not working properly, and adjustments should be made to the underlying setup to fix it rather than to switch tires to a tire that could lead to more traction roll issues and less consistency.

As stated above, one big issue could be that the car is not slowing down enough when coming off throttle due to virtual inertia and the low drag brake on the 33t motor. Offsets also play a pretty big role, as well as the Mosler body being a pretty low body that usually bottoms out on the track especially with softer springs (which are being run on this car). Things are hard to judge when reading about someones setup, without seeing how it looks, and what the track conditions are.

Being that he is a local NY racer, odds are that I have driven on the track that he races, and if it is the track that I think it is (Action RC), it has a lot of front bite, and I rarely use a 30d radial there. I usually use a slick 30 or LM30 if I need more front bite, and usually use ATM 40d slick-R, or Kyosho 40d radial on most of my cars there.

2011.04.13, 02:15 AM
I added some neutral brake from the Eurus and it made a world of difference to turn-in! Turn-out is fine now with quite a stiff diff and lowered gearings (51/12). Previous 51/14 was obviously too much for the 70t to handle and was kind of sluggish coming out of corners.

I also tried AW groove 10d tires up front and found them to have a tiny bit more grip than the 30d kyosho slicks. Ride seems smoother too but that could be because i'm still running really hard front springs (aw grooves being a soft silicone tyre).

Kyosho 20d radials had way too much grip and i had major troubles with the rear slipping all over the place.

For next time i'll lower the front a bit to see how that feels. How do you properly drop rideheight in an mr02 with stock knuckles? Shorter springs seem a better option than shimming the knuckle upwards.

2011.04.13, 10:21 AM
You can try a 19mm front wheel to lower the front (this is the method that I normally use)... shortening the spring alone will also increase the droop, if you want to go that route, I suggest shimming the knuckle to keep the droop/preload the same as you would have with the longer spring... otherwise you are changing more than ride height. With a smaller diameter wheel you dont change the suspension setting at all, but lower the front end, and increase clearance to the body.

Raj, if you are using Core, make sure that the card is not rubbing the front wheels...

2011.04.13, 10:35 AM

The card is not the problem. I am running 1.5 degree knuckles.
The car drove great as an Enzo but it just went crazy after changing to the Mosler.

2011.04.13, 12:41 PM

The card is not the problem. I am running 1.5 degree knuckles.
The car drove great as an Enzo but it just went crazy after changing to the Mosler.

The Mosler is definitely a more "pushy" body than the Enzo. It will drive smoother, but the Enzo will always be more aggressive. Like everyone else has said, you definitely have to hack off a bunch of the Mosler to get all the clearances right. If you arent sure if its dragging or not, color the bottom with a sharpie, run it, and see if any has rubbed away

2011.04.13, 04:14 PM
One thought: the Atomic shock has an adjustable droop limiter. If you want more off-power steering, make sure you adjust the limiter such that the rear pod is level with the chassis when completely unloaded (in the air). This will lift up your rear axle when you lift off the throttle, helping rotate the car a lot more. I relied on this to get more turn-in "swing" at RCX, and especially for the pushy Mosler this comes in handy.

Tuning in some sort of drag brake is generally handy for almost all Mod cars; it'll slow you down, keep you on the racing line, and the weight transfer will rotate the car.

One more thought, cutting out the rear of the Mosler drastically increases its ability to turn its heavy arse around on the track. I left out the taillights, cut the bumper to 19mm above ground, then even took out the license plate area.

If you try all these things and none work, then you might need to find a front end with more grip. WTF2 is good, PN A-arm is more complicated, but definitely generates a lot of grip.

2011.04.13, 04:23 PM
I find that a car with a heavy rear of the body tends to rotate into the corner harder than one with less mass (rear cutouts). This is all off throttle pendulum characteristics. I used to use bodies with a little more rear mass and drive them more like an RM than an MM... now I reduce the rear mass as much as I can and drive the car harder into the corner. I found that the heavier rear mass would be less consistent entering the corners and the on throttle push was a little too much.

2011.04.13, 05:16 PM
I was a big fan of the enzo on 2wd and awd, On 2wd I found that the enzo at action rc needed a wing to be even remotely stable, But many of the top guns at action used to run the enzo, The mosler I found when i tried it on a different track on 2WD was smooth but kinda unstable, it was ground for clearence and everything

AWD i used to prefer the enzo on rcp because it was 98 and u could run a wide rear