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rajiex
2011.05.19, 09:59 PM
I am running a Mazda Rx7 with a Atomic Rear Pod. This car rolls everywhere.

I have the Atomic DPS with only the top disk on, white stock MR03 springs in the front, Rt 246 one degree knuckles, PN-4 T-plate. I push down on the rear corners and the opposite front wheel goes up. I changed to a PN 94-98 pod and this problem goes away. I don't think that the chassis is tweaked

Any suggestions???

color01
2011.05.20, 04:37 AM
The shorter wheelbases turn harder, sometimes that's all you need to push the chassis beyond the boundary of traction roll. What is the rest of your setup? There are many things that can contribute to traction rolling and without knowing the base we can't necessarily suggest anything guaranteed to work. :)

rajiex
2011.05.20, 01:00 PM
The shorter wheelbases turn harder, sometimes that's all you need to push the chassis beyond the boundary of traction roll. What is the rest of your setup? There are many things that can contribute to traction rolling and without knowing the base we can't necessarily suggest anything guaranteed to work. :)

Its an MR-03 with Kyosho 30 radials in the front and 20 radials in the rear.
Atomic 90mm, Atomic DPS with top disc only. PN 50T.
PN4 T-Bar, Stock ME-03 with white springs. I am using EX-5 radio.

Only thing I can think of not to flip is dial down the steering. But the front wheel lifting up is killing me.

EMU
2011.05.20, 01:57 PM
30d radials in the front may be a little overkill. Do you have an ATM Slick-R 40 that you can try?

Also, maybe a slightly softer longitudinal but stiffer lateral t-plate may help... The leverage on the different mounts may come into effect, being that the t-plate flexes less with the 98mm mount for the same amount of movement. How much uptravel do you have with the 90mm mount? Are you running a top shock? I would recommend trying a Kyosho t-plate if you have one...

Does the inner front wheel lift on both sides evenly? Is the travel unrestricted by motor wires? What holes do you have the DPS post mounted on the damper arm and where is the DPS plate mounted? A picture of the setup would be helpful.

I feel that the shorter wheelbase would not need as laterally soft of a t-plate since the center of mass of the wheelbase is closer to the rear axle than it is on 94-98mm.... One thing to consider as well, is the location of the damper post, which is much further forward than it is with the 94/98 mount. The 94/98 mount has the damper post directly above where the t-plate mates with the mount, the ATM 90mm setup has the damper post directly above where the t-plate mounts with the chassis. This changes the properties of how the damper reacts to loading. Especially with only one plate being used. As you increase mass to the rear with the 90mm setup, the disc will load at a higher rate than the 94mm setup will, since the offset arm increases leverage.

While I cant really say my setup is right, I tried to keep my damper post as close to the pivot point as I could. I shaved the DPS plate, and damper arm for more clearance, and used the rear hole in both the DPS plate and DPS post. I also used two discs, and clearanced the PCB cover slightly for a standard DPS post. This is dangerously close to the motor wires, if you use screws to attach the wires. My 90mm setup is still a work in progress, but it drives pretty well (except that I have a busted servo gear right now to change out). I am currently using the FD3S RX7... with narrow wheels all around

Atomic-USA
2011.05.20, 02:20 PM
Raj, please see my responses below:

I am running a Mazda Rx7 with a Atomic Rear Pod. This car rolls everywhere.

*This is a known issue with 90mm Narrow running on RCP. You will need to lower the car to the ground; true the tires; use 19/18mm wheels; and lighten the body, etc....... Wide rear tires help; for Action I'd use ATM 40 SlickR front for Narrow or worn out K30s.

I have the Atomic DPS with only the top disk on, white stock MR03 springs in the front, Rt 246 one degree knuckles, PN-4 T-plate.

*I'm not familiar with a PN4 plate; try soft Fiberglass plates. ATM V.3 Damper springs are best for the ATM 90mm Mount.

I push down on the rear corners and the opposite front wheel goes up. I changed to a PN 94-98 pod and this problem goes away. I don't think that the chassis is tweaked

*Did you mean when you push down the front and the opposite rear lifts?

I should be stopping by ActionRC soon I'll take a look at your car. My 90mm is dialed on RCP and on carpet. It's very simple.

http://i9.photobucket.com/albums/a65/dealerxing/Mini-z/SAM_1324.jpg

rajiex
2011.05.20, 07:18 PM
Sai

The pn plate is the hardest I have. As for Tds spring, it's the hardest pn I have. When I push down on the front the rear stays planted. But when I push the down the rear the fronts wheels go up.

Got worn k30s on front and atomic v50 on rear. I have 19 fronts but regular size rims on the rear.

I got earplugs for u and a white noise machine for the limo.

Atomic-USA
2011.05.20, 11:07 PM
Sai

The pn plate is the hardest I have. As for Tds spring, it's the hardest pn I have. When I push down on the front the rear stays planted. But when I push the down the rear the fronts wheels go up.

Got worn k30s on front and atomic v50 on rear. I have 19 fronts but regular size rims on the rear.

I got earplugs for u and a white noise machine for the limo.

Get rid of the hard plate and hard DP spring and go soft. When you push down the rear(assuming the rear corner of chassis) I think the opposite front will always lift up. Check your other cars.

I'd use 19mm in the rear as well, preferrably wide tires on RCP.

EMU
2011.05.20, 11:18 PM
I dont know of any 19mm wide wheels... So if you go with a 19mm rear, it would be narrow. At Action the only rear tires I use there are Kyosho 20 rears... whether they are wide or narrow. For the RX-7 I would definitely use wide. FD3S; 0w, FC3S; -1w. I could never really get the FC3S to handle the way I like... FD3S is still not quite what I want, but better for me.

Dougboy
2011.05.30, 11:41 AM
Our local track is going to be running a hatchback series. Would the same apply if I were to run a 90mm MR015 with high mount and a body like vitz? Roll will almost be inevitable, will a stiffer T-plate be best?

EMU
2011.05.30, 02:24 PM
I would start with harder front spring/t-plate and front tires, and work your way soft to search for more speed if you feel you have enough stability and want to search for a little more speed... Make one change at a time, and see what it does to the cars handling, whether its a tire change, spring change or t-plate change. What HM are you using? Do you have a damper plate?

Dougboy
2011.05.30, 02:51 PM
I would start with harder front spring/t-plate and front tires, and work your way soft to search for more speed if you feel you have enough stability and want to search for a little more speed... Make one change at a time, and see what it does to the cars handling, whether its a tire change, spring change or t-plate change. What HM are you using? Do you have a damper plate?

Appreciate the quick reply. No disc damper but will get one if dampening will prevent the roll. Stock plastic mount for now lol, as it's just a "for fun" series and car is built from spare parts.

EMU
2011.05.30, 02:55 PM
I dont think the Kyoso plastic mount is disc damper compatible, you would have to invent your own solution... The ATM HM mount is DDS compatible, but it has been discontinued for some time now, and may be difficult to find. If you want to use a DDS, you may have to look into a 90mm MM mount.

Digitalis West
2011.05.31, 02:49 AM
I have been playing around with 90mm a lot preparing for the mini class at the KO GP III race. It was very tricky to get working because the short wheelbase is very twitchy and the tall mini-hatch bodies used made it worse. Taming the turn in and cornering is key to preventing rollover.

I ended up running a very stiff front end with Kyosho 40 slick front tires and a very soft rear end with lots of damping. The stiff front end and soft rear end transfers weight to the rear reducing front traction and preventing rollovers. This does tend to make the car push a lot meaning that you have to slow down for corners and be gentle on the throttle coming out of the corner. Increasing damping slows weight transfer on the car calming the car over bumps and giving back a little turn in. I generally run Kyosho 20 rears with this setup but some have experimented with harder rear tires (Kyosho 30 or PN-8) to reduce rear traction restoring balance to the handling with the hard front end. Reducing rear traction does not seem to be as fast in the race but the concept makes sense and it may be a matter of finding the right combination.

So... harder front tires with stiff springs, softer rear (PN-3, Kyosho Soft at the most..) and lots of damping if you can fit it on. With the front this stiff, I would not worry too much about lifting a front wheel during cornering.

color01
2011.05.31, 06:53 AM
If the track is smooth enough, you can also setup a hard rear end to reclaim some of your steering. I find that it's best to balance the setup between front and rear unless you have no other choice, as a hard front/soft rear setup can sometimes handle unpredictably (albeit still safely) in quick transitions.

EMU you don't like the FC3S? I rather liked how it drove on a Speedy07 MR015 with -0.5W rears, it got very close to traction rolling all the time but almost never went over; plus, it pivoted around turns as quickly as the F430 does. I want to try the FD3S at some point too on an RM chassis, I imagine the flatter setup overall will let me push the car harder before it rolls, and the RM config more turn-in "swing" which would be helpful with hotter motors.

rajiex
2011.07.21, 07:06 AM
Thanks for all the help and suggestions, I swapped the Mazda 7 (D) to the Porsche 911 GT3 and all my troubles went away without changing anything else. No traction roll, chattering almost stopped. Now the rear kicks out but I am more than happy.

skyler
2011.11.30, 04:11 PM
Hi Sai, Would you mind posting more pics of your 90mm setup? Thanks.

SaiTam
2011.12.04, 07:17 PM
Audi TT Body. 0/0 offset. 10 AW Rear / worn 10dV-groove or 20d V-groove front tire. Carpet Racing.

Front: Yellow springs; .5mm knuckles with enhanced larger bearing axles; N2 tower bar; Titanium Kingpin. Reverse kingpin/Alu. Lower Arm will go on soon. Just wanted to test how far I could push stock suspension setup in Narrow.

Rear: AR-265 90mm Mount. Pink V.3 spring. Atomic X-flex Stage 1 T-plate. -1mm Narrow offset Ball Diff.

Video -- TQ + winner: http://www.youtube.com/watch?v=qtzxJ7S7nvE&feature=g-upl

http://mini-zracer.com/forums/attachment.php?attachmentid=32377&d=1323044206

http://mini-zracer.com/forums/attachment.php?attachmentid=32376&d=1323044191


http://mini-zracer.com/forums/attachment.php?attachmentid=32375&d=1323044174


http://mini-zracer.com/forums/attachment.php?attachmentid=32374&d=1323044151



http://mini-zracer.com/forums/attachment.php?attachmentid=32378&stc=1&d=1323044372

Skv012a
2011.12.04, 10:10 PM
And correct me if I'm wrong here, but short and narrow setups, first and foremost, do not allow you to push the car nearly as hard through the corners as wide setups; so, you have to drive it MUCH more carefully and technically to avoid rolling.

I think adding some weight (metal rods) to the belly gaps between battery slots would also help overall. I'm personally trying to see if using aluminum wheels also helps lower and spread the weight around where these cars need it the most.

SaiTam
2011.12.04, 10:53 PM
On Carpet it is different. I could push my narrow as hard as I wanted. Notice my car is not lowered with 20mm wheels all around. Not one hatchback traction roll in the race I believe. Check video again.

Skv012a
2011.12.05, 02:38 PM
Then, I'll correct my train of thought towards RCP. I still have absolutely NO carpet experience, but definitely want to try it sometime.

rajiex
2011.12.08, 09:41 AM
Sai,

on my 90 Atomic mount, the discs barely make contact to the damper plate.. Should I shim below the mounting plate and top cover or shim between the spring and arm so that the disc makes contact..

Atomic-USA
2011.12.08, 10:11 AM
Yes, check my first photo above you'll see I put shims in mine too.

Skv012a
2011.12.08, 07:30 PM
My disk isn't horribly pressed against the plate, but that fairly loose feel really does its magic.

rajiex
2011.12.09, 06:34 AM
Yes, check my first photo above you'll see I put shims in mine too.

That did the trick, keeps the rear planted and eliminated a lot of chatter.
Thanks,=..

arch2b
2013.08.16, 10:15 PM
i'm thinking about getting the kyosho CE28N wheels which are 17mm front and i assume standard 20mm rear. does this much smaller diameter front wheel make a noticeable difference? i am currently running the atomic S6 19mm front and 20mm rear. i prefer the smaller diameter front wheels just to give a fraction better tire clearance on the inside of the shell. i always seem to be scrubbing something with 20mm wheels.

arch2b
2015.03.29, 04:23 PM
anyone able to get the mr-02 atomic 90mm rm damper kit to work with 90mm mr-03? i have the damper, rm t plate and motor mount but nothing is lining up at the t plate holes for 90mm.

EMU
2015.03.29, 07:52 PM
anyone able to get the mr-02 atomic 90mm rm damper kit to work with 90mm mr-03? i have the damper, rm t plate and motor mount but nothing is lining up at the t plate holes for 90mm.

Are you using an rm or mm t-plate? I used both the rm and mm 90mm config on an mr03 for a short time without much complication. Are you using rm or mm mount? If you can post a pic of the top and bottom view that would help diagnose the issue...

arch2b
2015.03.29, 08:53 PM
RM t plate, RM atomic motor mount. can';t explain why the damper posts just are not aligning right. they are about 4mm to far back. maybe the newer version motor mount isn't the same as the original that was coordinated with the damper. :confused:

byebye
2015.03.29, 09:36 PM
Got pics? I'm not picturing it.

arch2b
2015.04.05, 11:33 AM
here... wrong RM mount?

arch2b
2015.04.05, 12:02 PM
never mind, brain fart having not used this is god knows how many years. set the RM t plate to 94mm, the axle alignment is shortened in the mount to account for this and the damper aligns with the mount holes. :rolleyes:

byebye
2015.04.05, 07:06 PM
never mind, brain fart having not used this is god knows how many years. set the RM t plate to 94mm, the axle alignment is shortened in the mount to account for this and the damper aligns with the mount holes. :rolleyes:

Glad I could help...:p