M-Technic

iTrader: (15)

I don't agree with a lot that has been said about your setup already (especially going to a 2.8 front spring or reducing your rear toe, neither of which will help your situation, rather hurt it). So I will make my own suggestions:

-First thing to do would be to remove 1mm or 2mm of shims from the rear upright (where you now have 5mm). This alone should fix your lack of rear grip.
-Try 4 holes open for the pistons in the rear shocks.
-The next thing would be to try removing the anti-squat and going to -0.75 roll center holders all the way around in the back.
-The final change would be to shorten the wheelbase, you are running full long which can make the car more stable but reducing overall grip.

I would not have cut the top deck either, but oh well.

One other thing to consider is that your roll centers on the camber links are quite low (i.e. mounted up high), allowing the car to roll more. I can't see a mention in any of your posts about the type of track you race on, but if it's medium to high grip asphalt I think the roll centers are too low. I basically always ran my car with the L1/L2 holders in the lower/longer position on the shock tower.

Meradin

iTrader: (19)

Not sure I am the best to give a review of this. In fact the only reason I considered this was the positive reviews already given and the fact that the new 2012 model has a cut top deck already.

Meradin

iTrader: (19)

I will give this a shot. The 5mm shims came from a setup sheet from Paul L on the xray site. Just figured he was a good place to start.



I may give this a shot down the road, don't have time tonight to change the piston over.

So raise the rear arms all the way up?

I thought I had it slightly shorter but I will check. I need the stability down the staights and currently have plenty of turn in. I will experiment with this.


I am running in what others report as low traction carpet with rubber tires on a small track. 17.5 blinky.

Here is a pic of the track
http://www.rctech.net/forum/9880636-post1333.html

HarryLeach

I ran into a very similar situation with my car getting very loose mid-corner and not able to accelerate off the corner very strong without spinning out.

I discovered the T3'11 doesn't like much, if any, split in the front and rear shock oil. Especially if you have any tight turns to negotiate. Try dropping your front shock oil to 350cst, same as your rear shocks and see if that helps the rear end stick.

Bigz84

iTrader: (23)

yeah i did that too, it calmed the front end down from digging in to hard. that helped. i tend to get too loose at corner exit now. should i:

more rear camber, i'm at 2 degrees and 3.5 rear toe, sweeps 32 tires on carpet
take out 2 top deck screws in rear to give it more flex???
or something else??

any suggestions

M-Technic

iTrader: (15)

Nothing wrong with starting with one of Paul's setups. Reducing those shims will help lock in the rear grip a lot, and adding more shims back free's up the rear of the car and gives you more steering.

OK, thought you'd be running the clicker pistons, that's why I suggested it.

No, -0.75 is all the way down.

I just looked again and yeah, it looks like you are 1mm short of full-long in the rear. I forgot there are 3mm of shims in the rear.

That sure is a small track! For low traction carpet, I think your camber link roll centers are fine then. I am sure you need that roll.

M-Technic

iTrader: (15)

Loose on corner exit, the first thing to try is to add some more droop to the front. Leaning the rear shocks in more and/or lighter oil in the rear (or open the pistons up) can help also.

Meradin

iTrader: (19)

Thanks, I wished that this was addressed somewhere in the setup book as clear ar you stated it. I know it has to do with the roll center but I like your description a lot better!

My only concern is reducing the steering too much as those are tight corners. My first race day was terrible and I couldn't get around those corners at all. I will take 1mm away and see what that does.

So far you are the only person I have read that even remotely suggests using them or imply using them. I have heard they are terrible and not to even bother with them.

oops, misread that one!

Would shortening up the rear help? I need the steering but as I am still a novice driver the stability is a must!

Very small, but fun! There is another club that races on a bigger track but it is tough to get to. I really like the atmosphere at this track. When we get 6 or more cars on this track it can be a smash fest. I just hang back then and it becomes obsticle avoidance. I like to think I am no longer one of those obsticles!

Would you suggest moving the rear shocks up a hole? I remeber that being suggested and it shows on the basic rubber setup the rear shocks being in the middle while almost all of Pauls setup have the rear shock laid down.

M-Technic

iTrader: (15)

There are always trade offs. You might lose steering by increasing your rear grip. Sometimes you have to change multiple things to get your desired end result.

I love them. I tune with them almost every time I am at the track. Never had any issues. I think it is one of the advantages Xray has over the competition. Who really wants to rebuild their shocks at the track just to change the damping?

I would go back to the kit wheel base. The car will generate more traction and rotate better in those tight corners. I can't see why you would need any straight line stability with such a short straightaway in 17.5 blinky.


I ran the rear shocks all the way down 99% of the time on the 2011. In the front I usually ran the 2nd hole from the outside (more responsive), sometimes the 3rd hole from the outside (more front bite, especially mid corner). Standing your rear shocks up more would reduce the side bite and rotation of the car, which I think is the opposite of what you are seeking.

I'd like to add that I am better with setup when the car is in my hand (especially if I can drive it myself) so all the advice I've listed are ideas for you to try. They may or may not solve or help your problems. One thing you will learn with car setup is that changes don't always result in the expected result!

Meradin

iTrader: (19)

Ummm...my bad driving!

I will leave them down.


Yup, everything I read I don't take at face value as there are so many differences in setup and conditions. You have provided me with exactly what I was looking for...a place to start.

As far as gettin your hand on the car, come on over to our track. We race every Friday night and you can run and tweak my car as much as you'd like!

HarryLeach

I would add .5-1mm more droop in the front before laying down the rear shocks or going to lighter oil. My car has great steering at all parts of the corner as long as I'm not jerking the steering. Driving style has as much to do with the corner speed you'll have as setup. With the droop change, concentrate on steering the least amount you can get away with, and as smoothly as possible, your lap times will thank you.

For camber, I look at tire wear and adjust from there. If the tire wear looks pretty even across the entire tire, I adjust other things to gain grip. If you're getting a "death ring" on the inside of the tire [I've had this on the rear even], or the tire looks almost new on the outside 1/4 of the tread, try taking some camber out of that end, or work on reducing your camber gain and finding a new happy place on your roll center.

Front end settings can have an impact on rear grip on corner exit as well, too much ackermann, too much caster, etc.

Hard to give a firm answer on things to try without looking over your setup sheet.

Bigz84

iTrader: (23)

I'm a little full trigger happy, but have been practicing to stop that. funny, when you think you drive slower, your lap times are better... anyway....

i'm running 2mm ackerman and just past 1mm of camber in the front and i'm still getting the ring of death. should i add a 1mm of bump steer under the steering block? on a setup station that is about how much it changes. rear tire wear is fine. rear shocks are laid down fully, 350cst oil and 3 holes open, 2mm camber. stock camber link setup. i sauce full rear and 1/2 of the front.

thanks for your info/help

kinga

iTrader: (15)

I think the setup sheet should have the option of adding a URL or google maps geotag for the track layout or picture so we all know what the track looks like size and layout wise.
Here is a link to our track layout vids so you know what I am talking about in reference to setups.
http://www.wynnumrc.com/index.php/rc-videos
Here is a link to my current setup
http://forum.teamxray.com/xform/inde...&setup=t3_2011

HarryLeach

Are you measuring camber in millimeters, or degrees?

Once you start getting the ring of death on a tire, you're not going to get it to go away, you can just adjust the camber and toe to try to prevent it from happening on a new set.

On my car, I think I'm between .5 and 1 degree in the front for asphalt, and run between 1 and 2 degrees in the front for carpet.

For bump steer, you want to shim under the steering link so that you have the least amount of bump steer from your ride height to full suspension compression you can manage.

JamesReilly

iTrader: (59)

Hey Todd,
Why don't you swing by my pit on sunday and we can get you some more rear grip figured out.

How many runs do you have on your tires??

LMK.

-James