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View Full Version : Top Shock thoughts for soft setup


JeremyC
2009.12.21, 02:14 PM
Right now I am running my car with either a super soft, or soft H-plate, a DSS and no top shock. I have found that my car works the best for me like that.

The current problem that I have with this setup is that the rear of the car droops a lot. I used to run ATM FRP plates, but now run PN SSG plates because they last longer.

To raise the rear of the car I installed one of those triangular H-plate mounts designed for the long RM H-plates. This brought the ride height to the right spot and the car still drives well. The problem with this solution is that it puts more strain on the H-plate, and unsurprisingly, I started to break H-plates.

Since breaking H-plates is not fun I am thinking of getting a top shock strictly to control droop, and to go back to a regular h-plate mount.

Any recommendations for a top shock? I'd like to keep the weight gain to a minimum.

minittrackmann
2009.12.21, 02:19 PM
The new PN shock is great. Although it is not oil filled. I like the Atomic top shock. Weight is minimum and its smalland compacted. Easyto install and adjust also.

mleemor60
2009.12.21, 02:32 PM
If you are going to use it strictly as a crutch so to speak then all you actually need is the little stock damper that comes with the car. It is virtually weightless. You can change springs on it an you can even "dope" the shaft with your choice of silicon grease or whatever kind of schmaltz you want.

JeremyC
2009.12.21, 03:23 PM
MZ206B is the rear shock assembly, but doesn't come with any springs. Looks like you need Kyosho MZW213 to go with it.

The PN spring MR2161 looks really nice, it does look heavy though.. Nice to have the spring set MR2162 readily available for it.

blt456
2009.12.21, 03:35 PM
Hey Jeremy.. I drove an expert's car (local) and the PN shock and spring set is the way to go.. the f1 shock is smaller in diameter, lighter and is harder, which could be good for you if the car sags..

VAzRACER
2009.12.21, 05:03 PM
The F1 rear shock has worked the best for me so far. I tried the PN shock on a couple cars but was always slower with it. It seems to stiff for me even with the softest spring on it.

Sometimes you have to modify the F1 shock to get it working better.

EMU
2009.12.21, 06:30 PM
Almost all of my cars either have the stock shock with alternate spring (depending on chassis setup and body choice), or the F1 shock. I use a little grease with them as well. Oil shocks are a little too much maintenance, especially since you are already using a DDS.

luvs2hate
2009.12.21, 06:39 PM
I see a lot of the fast guys use top shocks but racers in my area (northeast) dont use top shocks. They achieve the correct ride height but the preloading of the bottom DPS spring.

Tjay
2009.12.21, 06:46 PM
Hi JeremyC,

I too use to have this issue with my MR02. Most of my previous setups had this top shocks with ATM but that's before PN came out with their top shocks. If you plan to use just that (get rid of that rear sag), you should also consider adjusting your motor pods damper arm. This is what I do and haven't had any problems with it. I dont use thread lock or super glue. Just PN m2x4 machine button head and I'm good to go. This is if you have PN pod v1.

Arm moved back a little for no droop with soft lower springs for better bump absorption.
http://i52.photobucket.com/albums/g10/Teejay_Cynthia/FPR%20Mini-Z/IMG_1009.jpg?t=1261438530

If you have to use top shocks, I would suggest to buy PN or use stock and install softest spring you can find. This way the rear end doesn't bounce all over the place.

Hope this helps. Good luck! :)

Tjay
2009.12.21, 06:50 PM
This is how it looks like from top view.

http://i52.photobucket.com/albums/g10/Teejay_Cynthia/FPR%20Mini-Z/IMG_1010.jpg

EMU
2009.12.21, 08:57 PM
I usually use a stiffer upper spring on my DPS or preload it more than the lower. I like a soft lower spring, I feel it helps smooth out the bumps better, and gives consistant traction. I usually use the green or blue spring for the stock top shock (dont remember what company I got the blue from, 3Racing probably but it is my favorite).

The preload of the DDS has a lot to do with the preload of the t-plate, take that in mind when you adjust your DDS and top shock (if you use one). I like the t-plate to be preloaded with the car not on the ground. Just a little bit. I find that it helps take out some of the bounce in the rear. When there is no load on the t-plate, I feel like the rear end is less consistant, and doesnt transition as well on/off power.

A stiffer lower DDS spring will give you more on power steering, but traction is much less consistant over bumpy terrain. Especially when using an FRP t-plate. A stiffer upper spring will pull the motorpod up a little (preloading the t-plate), and give a smoother load on the t-plate as you accelerate.

JeremyC
2010.01.02, 10:01 PM
I usually use a stiffer upper spring on my DPS or preload it more than the lower. I like a soft lower spring, I feel it helps smooth out the bumps better, and gives consistant traction. I usually use the green or blue spring for the stock top shock (dont remember what company I got the blue from, 3Racing probably but it is my favorite).

The preload of the DDS has a lot to do with the preload of the t-plate, take that in mind when you adjust your DDS and top shock (if you use one). I like the t-plate to be preloaded with the car not on the ground. Just a little bit. I find that it helps take out some of the bounce in the rear. When there is no load on the t-plate, I feel like the rear end is less consistant, and doesnt transition as well on/off power.

A stiffer lower DDS spring will give you more on power steering, but traction is much less consistant over bumpy terrain. Especially when using an FRP t-plate. A stiffer upper spring will pull the motorpod up a little (preloading the t-plate), and give a smoother load on the t-plate as you accelerate.

I've played with changing the DDS springs, and I honestly couldn't feel that much of a difference when driving. On the bench I could tell that the rear would move differently, specifically with a stiffer top spring it would help with the droop issue(much like tjay suggested). Need to get more 'seat time' to feel small differences as these.

In any case, I got an ATM top shock in a trade, and put it on the car. I'm using a stock MR-02 front spring on the shock and the rear feels brilliant. I have a soft SSG plate on the car, minimal droop, and soft flex.

Running the car with Kyosho slick 30 fronts and Kyosho slick 20 rears I had excellent rear traction. The car handles very neutral, but I think a little understeer. I should try some softer front springs I suppose..

DANR
2010.01.02, 11:35 PM
I'm actually in the process of testing the effects of different DDS springs on my MR02 right now.

Using our I-Lap RC system on our Mini-96 RCP track, I've been going through each of the possible combinations of springs. I've been keeping the bottom spring the same, and then swapping the top spring through the 3 possibilities (Red, Green, Blue), and then moving on to the next bottom spring and doing it all over again. As it stands, I've only finished having the setups with the Soft and Hard springs on the bottom (the Hard Spring on the bottom will come later).

For my testing, I've run each setup through basically a full charge of batteries, and recorded the fastest laps for each setup.

Based on my (limited, thus far) findings, adjusting the DDS springs can save up to 0.6 seconds per lap on my track (slightly shorter than a standard Mini-96 due to space constraints)

If I didn't have the timing system, I probably wouldn't notice that much of a change, but with it in place, it is very interesting to see.

EMU
2010.01.03, 03:11 AM
I've played with changing the DDS springs, and I honestly couldn't feel that much of a difference when driving. On the bench I could tell that the rear would move differently, specifically with a stiffer top spring it would help with the droop issue(much like tjay suggested). Need to get more 'seat time' to feel small differences as these.

In any case, I got an ATM top shock in a trade, and put it on the car. I'm using a stock MR-02 front spring on the shock and the rear feels brilliant. I have a soft SSG plate on the car, minimal droop, and soft flex.

Running the car with Kyosho slick 30 fronts and Kyosho slick 20 rears I had excellent rear traction. The car handles very neutral, but I think a little understeer. I should try some softer front springs I suppose..
Where in the corner do you feel understeer? Changing springs will not increase the amount of steering your car has in the corner, it changes the amount of initial steering you have. A very soft spring will have more initial steering, but after the spring is fully loaded, you will lose steering on the exit (like rolands cars generally, very fast early response, but lack of mid/exit steering). A harder spring will take more time to load, so it will typically have less steering at turn in, and more on the exit. Knowing where in the corner you the faster response should dictate the spring. Small tight tracks, softer front springs work better. Larger tracks, I want more exit steering/speed, so I go with a harder front spring (usually ATM orange/PN white). Wide offset fronts I use yellow springs, since the leverage that the offset gives requires a harder spring to have the same rate at the wheel...

I like the ATM top shock, but it does take a little more tweaking than a normal top shock...

I used no shock on top of my MR03 today, first time in a long time that I havent had a shock... I have a #5 t-plate (2nd from stiffest), and had good results. I used red springs on the DDS, with upper spring preloaded. Grease on the DDS as well. Car felt good, and I dont think I will add a shock. PN70t motor, which is required for the class. With a faster motor, I would definitely use a shock.

JeremyC
2010.01.03, 10:57 AM
For my testing, I've run each setup through basically a full charge of batteries, and recorded the fastest laps for each setup.


I like your scientific approach to the problem, but I think you need more test runs to make it more statistically significant. There is so much variation from user input that I haven't really tried this type of testing, maybe I should..

Where in the corner do you feel understeer?

Turn out seems to be the problem. The car is very nimble running 94mm. It is running a soft PN SSG plate, and PN red(soft) upper/lower DDS springs.

However, the car feels good. I'll play with DDS springs to see how it adjusts.

I like the ATM top shock, but it does take a little more tweaking than a normal top shock...


I've never owned a kyosho stock top shock, so I can't comment. It seems like you need to user preload shims to adjust it, so that seems annoying.

The ATM shock in 94mm does require attention though; especially if you are using an MR-02 front spring. When I first set it up the spring could only compress 1mm or so because the adjusting collar was hitting the rubber ball that the shaft goes through. I flipped the collar over and it works fine now. Pictures would explain better.

I also noticed that the threads of the shaft sometimes rubbed on the ball, so I needed to screw that in as far as I could without limiting down travel. So yes, the shock does require tweaking and attention. If I was running 98mm and using the spring that came with it; it would be easy. Then again I never seem to do anything the easy way.

DANR
2010.01.03, 02:25 PM
I like your scientific approach to the problem, but I think you need more test runs to make it more statistically significant. There is so much variation from user input that I haven't really tried this type of testing, maybe I should..

I completely agree with you. Something I didn't mention is that I broke down each setup into individual 10 minute intervals, and took the fastest laps from each of those intervals and compared them.

Granted, I'm still pretty new at this, and I'm still not the most consistent of drivers, but I'm still getting within a tenth or so for each of the fastest laps for a particular setup.

And it is very driver dependent, as it seems that I'm getting quicker (on my track) as I start using stiffer springs, and it seems that the more common setup, from what I can read, is a softer rear.

luvs2hate
2010.01.03, 04:17 PM
In my experience a softer top shock spring turns less going in, but more out (same goes for less preload/lower ride height)

JeremyC
2010.01.04, 12:23 AM
I was at the track again today and put a few solid hours into the car with the shock. My impression is that the rear of the car is very stable.

Sitting here I just had the realization that I really can't get the rear of the car to slide. On power it doesn't spin; even with a tight diff. I didn't push too hard to test for trailing throttle oversteer, but it never once showed a hint.

I also found that I couldn't get the car to rotate as fast by using the brake. I have used this as a way to spin the car for some time, but with the Kyosho 20 rears, soft T, top shock, and smooth DDS, well, the car just doesn't spin as much. It does spin, and if I hit the brakes while turning it'll snap around, but not as violently as it used to. I had to increase my brake endpoint to compensate.

And before we get to DDS springs, no, I didn't mess with them. The car was working well, and I didn't want to muck it up.

mk2kompressor
2010.01.04, 06:13 AM
when we use super soft H-plates with the atm topshock,an orange MR-02 atm front spring is the best found so far

JeremyC
2010.01.04, 10:14 AM
when we use super soft H-plates with the atm topshock,an orange MR-02 atm front spring is the best found so far

As I said I'm running a stock MR-02 front spring, because I wanted the softest I could find. Even with that, compressing both rear wheels up is fairly hard to do (especially compared to no top shock).

Does the top shock spring only control droop and vertical spring rate? Why did you not like other springs?

CondeAfonso
2010.09.16, 08:55 PM
Hi there JeremyC!

Just thought I should chime in since I'm having more or less the same problem as you (trying to find the softest bar, while avoiding the drop on the chassis).

The first thing you have to notice is that the triangular bar you use, totally changes the purpose of the softer bar. It will reduce the leverage of the bar a LOT and wont allow it to flex on all the length. The reason why they break is that you reduced the usable length of the bar by half with the triangular mount, and you are still asking it to flex as much. If you are using a motor mount that allows axle height adjustment go there first, this should be the easiest solution without changing the behaviour of your setup.

Changing the springs on the friction damper will also virtually make the plate harder, both in longitudinal an lateral movement, as it provides friction in every direction.

And yes, the addition of a top damper will only make the suspension harder in a longitudinal movement. If you can't adjust the axle and need to use a damper, start from the softest spring you can find, and give the pre-load necessary (using shims for example) for the ride height to go back to place. Avoid going for a harder spring unless the softer one bottoms out on compression.

My car setup is for a totally different use (I don't use friction damper as I need the suspension to change as quick as possible), but I still use the softest bar I can, and the top shock just to control the compression so it doesn't bottom out on acceleration. The shock I'm using is the Atomic Ar-181. You can also get softer front springs than the stock ones.

JeremyC
2010.09.16, 09:45 PM
Hi there JeremyC!

Just thought I should chime in since I'm having more or less the same problem as you (trying to find the softest bar, while avoiding the drop on the chassis).

The first thing you have to notice is that the triangular bar you use, totally changes the purpose of the softer bar. It will reduce the leverage of the bar a LOT and wont allow it to flex on all the length. The reason why they break is that you reduced the usable length of the bar by half with the triangular mount, and you are still asking it to flex as much. If you are using a motor mount that allows axle height adjustment go there first, this should be the easiest solution without changing the behaviour of your setup.

Changing the springs on the friction damper will also virtually make the plate harder, both in longitudinal an lateral movement, as it provides friction in every direction.

And yes, the addition of a top damper will only make the suspension harder in a longitudinal movement. If you can't adjust the axle and need to use a damper, start from the softest spring you can find, and give the pre-load necessary (using shims for example) for the ride height to go back to place. Avoid going for a harder spring unless the softer one bottoms out on compression.

My car setup is for a totally different use (I don't use friction damper as I need the suspension to change as quick as possible), but I still use the softest bar I can, and the top shock just to control the compression so it doesn't bottom out on acceleration. The shock I'm using is the Atomic Ar-181. You can also get softer front springs than the stock ones.

Lots to think about in your post. My car has changed quite a bit since I was having these troubles. At this point it is setup for 98mm with no top shock. I haven't driven it in so long I am a little concerned, but tomorrow we'll see how it goes.

:)