Hot Bodies Cyclone
10-23-2009, 04:56 PM
I've always found rebound to be a pretty fine adjustment. I usually always run full or no rebound at all... because I can barely tell the difference. After running into some situations where adjusting it has helped, what I explained before are the situations on where the adjustments were successful. Hiro is busy racing this weekend, but maybe he can pop on here and say what he thinks and Peter as well.
-Korey
-Korey
But we really can't say "more rebound" means more or less traction because it just changes how linear the shocks move up and down. I got to give prop to Peter for his great explanation for this part. it is well explained.
With more rebound (i.e 100%), the shock shaft comes back out faster by the pressure above the piston. That means the car comes back a little faster when it rolls. Also, more rebound generates a bit more tire pressure to the ground so sometimes more rebound makes more traction overall. As Korey mentioned earlier, this pressure on the tires also generates more tire heat as well.
In the bumps, I really don't think that the rebound adjustment should be used for this as we basically tune/adjust it by anti/pro-squat in the rear or kick up in the front. In fact, in off-road category they almost never use 100% rebound even if they have to deal with the track that is way more bumpier. May be in some situation, more rebound such as 100% might works but i believe that we can get better result with proper setup on the suspension angle.
Basically, the shock absorber(without spring) should work for damping effect only since the down stroke force will be generated by the spring. Just like Ray (aka: Pound It Racing) said previously, the shock absorber controls the shock moving speed and the up/down stroke movement should be controlled by the shock spring.
However, with using the adjustment of the shock rebound percentage, we can also fine tune the shock movement. But again, this will change how linear the shock moves for both up and down stroke only so i don't think we can say that easy which is more traction or something like that.
I hope it helps a bit...
10-23-2009, 04:58 PM
Team HB is like Voltron... Together we make a good explanation!!!
10-23-2009, 05:14 PM
Korey, were does STLNLST fit in Team HB's Voltron, the BACKSIDE??? 
10-23-2009, 07:31 PM
The damping of the shock is determined by the piston and oil, it's measure will be the same no matter the spring used. a particular piston and oils damping has a range of spring it will work with, a soft spring needs less damping than a stiff spring.
I disagree that rebound any effect on damping itself and only serves as a progressive air spring in addition to the coil spring, and in that capacity changing the total spring rate, effectively raises the spring rate compared to the damping rate. It's a very minor point and doesn't change any of the observations presented about rebounds effect on the car.
10-23-2009, 07:58 PM
Go team HB. What little part I donated. It's good to know that we can ask a really tricky question and have a few people give the same answer using different examples and word usage. I feel like I went to a physics class today. I love this stuff.
10-23-2009, 11:48 PM
10-24-2009, 08:07 AM
While on the subject of shocks, does using a vacuum pump make a difference when building the shocks ? I know what it does, I watch a fellow racer at my track use one and he swears by it. I have built shocks and rebuilt them a month later and found no air bubbles inside without using a pump or even letting them sit for for any length of time before putting the cap on.
Thanks.
10-24-2009, 08:55 AM
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Enough speculation 
What you need is some way to read the suspension movement while the car is going around the track ie shock potentiometers, maybe a IR or sonar setup so it doesnt interfere with the shocks action then hook them up to a data logger to see what is happening between rebound and no rebound.
Also, make a shock dyno for rc shocks to test the difference between rebound and no rebound. I dont know if its possible to get load cells that will measure loads that small, Im sure there is something out there.
Food for thought...
What you need is some way to read the suspension movement while the car is going around the track ie shock potentiometers, maybe a IR or sonar setup so it doesnt interfere with the shocks action then hook them up to a data logger to see what is happening between rebound and no rebound.
Also, make a shock dyno for rc shocks to test the difference between rebound and no rebound. I dont know if its possible to get load cells that will measure loads that small, Im sure there is something out there.
Food for thought...
10-24-2009, 09:30 AM
If anyone is interested... i have (2) black cyclones for sale. PM me
10-24-2009, 03:07 PM
While on the subject of shocks, does using a vacuum pump make a difference when building the shocks ? I know what it does, I watch a fellow racer at my track use one and he swears by it. I have built shocks and rebuilt them a month later and found no air bubbles inside without using a pump or even letting them sit for for any length of time before putting the cap on.
Thanks.
Thanks.
I do know that if you create too much of a vacuum it will suck air right through the bottom of the shock and through the orings. I've always found just pumping them up and down a few times to release any air bubbles hiding in there works just fine. I just let the shocks sit on a shock rebuild stand for a few minutes before finishing up the rebuild.
-Korey
10-25-2009, 06:24 AM
NEW HIGH GRIP TRACK
Hi Korey,
Another tricky set of questions. I have been running on a low grip track, and have just started running on a newly refurbished high grip track.
(1) The low grip track now seems under control, with a setup similar to Hara at RROC 2008.
(2) The new track is turning into a challenge for most drivers. The asphalt surface has been cleaned up, and the track has been repainted with a Boral anti-slip paint (like one might use around a swimming pool). Another club in Sydney used this paint about a year or so ago, and it worked out ok after a few months. Allegedly a high grip surface. It was painted with a paint roller, and apparently the stipples left by the roller actually create more grip for about the first 3 months, until they are worn down.
(3) The main problem is trying to get power down to the rear wheels. Unless the car is in a perfectly straight line, the rear end just rotates around under the mildest of power. My end of day setup seemed the best of a sub-optimal lot, but I don’t feel comfortable running an RC that is lower in the rear, than the front (I'm thinking there must be a better, more widely used setup to get around this challenge).
(4) I'm tending to coast around the corners because of the rear end rotation when powering on. After about an 8+ minute practice run, there is a lot of rubber inside the body shell.
(5) NEW HIGH GRIP TRACK SETUP (end of day setup):
Drive: ________F=SpoolV3 + R=Diff
Ackermann: ___F=4.0
Shock Spring: __F=Pink + R=Silver (* tried F=Silver + R=Silver & tried F=Pink + R=Blue*)
Shock Oil: _____F=AE60 + R=AE35 + FullRebound + Foam (tried F=45 + R=35 *)
Shock Piston: __F+R=2hole,1.2mm
Shock Position:_F=3+2 + R=3+3 (* tried R=3+5 *)
Camber Link: ___F=2.0 + R=1.0 (* tried F=3.0 + R=0.0 etc *)
Camber: _______F=1.5 + R=1.5 (* tried F=2.0 + R=1.0 *)
Toe Block: _____F=1.5 + R=3.0
Toe: __________F=+0.5
Block Shims: ___F=2.0 + R=1.5 (* tried F=1.0 + R=1.5 *)
Wheelbase: ____F=2.0_0.5 + R=2.0_0.5 + R(hub)=2.0_0.5
Swaybar: ______F=1.4 + R=1.2
Swaybar Gap: __F=1.0 + R=2.0
Downstops: ____F=9.0 + R=9.0 (* tried F=8.5 + R=8.0 *)
Ride Height: ____F=5.5 + R=5.5 (* tried F=5.0 + R=5.5 *)
Middle Deck: ____Cut
Body: __________Mazda6
Tires: ___________Sorex32 + B_MediumInserts + SpeedmindRims
(6) I did not rotate the tires. The rear tires are looking ok, however, the front tires have worn through to the canvas in a couple of spots, and the inner rim of the front tires are split.
(7) The track is tight and technical, except for a sweeper onto the main straight (and then into a 180 degree hairpin at end of straight).
(8) I'm not 100% certain (so take this with a bit of scepticism) but I think the car gets through the corner entry and maybe middle but then rotates if slight braking or on power is applied. Might even be pushing mid-corner.
Any suggestions GREATLY appreciated.
Cheers
Another tricky set of questions. I have been running on a low grip track, and have just started running on a newly refurbished high grip track.
(1) The low grip track now seems under control, with a setup similar to Hara at RROC 2008.
(2) The new track is turning into a challenge for most drivers. The asphalt surface has been cleaned up, and the track has been repainted with a Boral anti-slip paint (like one might use around a swimming pool). Another club in Sydney used this paint about a year or so ago, and it worked out ok after a few months. Allegedly a high grip surface. It was painted with a paint roller, and apparently the stipples left by the roller actually create more grip for about the first 3 months, until they are worn down.
(3) The main problem is trying to get power down to the rear wheels. Unless the car is in a perfectly straight line, the rear end just rotates around under the mildest of power. My end of day setup seemed the best of a sub-optimal lot, but I don’t feel comfortable running an RC that is lower in the rear, than the front (I'm thinking there must be a better, more widely used setup to get around this challenge).
(4) I'm tending to coast around the corners because of the rear end rotation when powering on. After about an 8+ minute practice run, there is a lot of rubber inside the body shell.
(5) NEW HIGH GRIP TRACK SETUP (end of day setup):
Drive: ________F=SpoolV3 + R=Diff
Ackermann: ___F=4.0
Shock Spring: __F=Pink + R=Silver (* tried F=Silver + R=Silver & tried F=Pink + R=Blue*)
Shock Oil: _____F=AE60 + R=AE35 + FullRebound + Foam (tried F=45 + R=35 *)
Shock Piston: __F+R=2hole,1.2mm
Shock Position:_F=3+2 + R=3+3 (* tried R=3+5 *)
Camber Link: ___F=2.0 + R=1.0 (* tried F=3.0 + R=0.0 etc *)
Camber: _______F=1.5 + R=1.5 (* tried F=2.0 + R=1.0 *)
Toe Block: _____F=1.5 + R=3.0
Toe: __________F=+0.5
Block Shims: ___F=2.0 + R=1.5 (* tried F=1.0 + R=1.5 *)
Wheelbase: ____F=2.0_0.5 + R=2.0_0.5 + R(hub)=2.0_0.5
Swaybar: ______F=1.4 + R=1.2
Swaybar Gap: __F=1.0 + R=2.0
Downstops: ____F=9.0 + R=9.0 (* tried F=8.5 + R=8.0 *)
Ride Height: ____F=5.5 + R=5.5 (* tried F=5.0 + R=5.5 *)
Middle Deck: ____Cut
Body: __________Mazda6
Tires: ___________Sorex32 + B_MediumInserts + SpeedmindRims
(6) I did not rotate the tires. The rear tires are looking ok, however, the front tires have worn through to the canvas in a couple of spots, and the inner rim of the front tires are split.
(7) The track is tight and technical, except for a sweeper onto the main straight (and then into a 180 degree hairpin at end of straight).
(8) I'm not 100% certain (so take this with a bit of scepticism) but I think the car gets through the corner entry and maybe middle but then rotates if slight braking or on power is applied. Might even be pushing mid-corner.
Any suggestions GREATLY appreciated.
Cheers
Last edited by cosmo1974; 10-26-2009 at 02:11 AM.
10-26-2009, 11:51 AM
Hi Korey,
Another tricky set of questions. I have been running on a low grip track, and have just started running on a newly refurbished high grip track.
(1) The low grip track now seems under control, with a setup similar to Hara at RROC 2008.
(2) The new track is turning into a challenge for most drivers. The asphalt surface has been cleaned up, and the track has been repainted with a Boral anti-slip paint (like one might use around a swimming pool). Another club in Sydney used this paint about a year or so ago, and it worked out ok after a few months. Allegedly a high grip surface. It was painted with a paint roller, and apparently the stipples left by the roller actually create more grip for about the first 3 months, until they are worn down.
(3) The main problem is trying to get power down to the rear wheels. Unless the car is in a perfectly straight line, the rear end just rotates around under the mildest of power. My end of day setup seemed the best of a sub-optimal lot, but I don’t feel comfortable running an RC that is lower in the rear, than the front (I'm thinking there must be a better, more widely used setup to get around this challenge).
(4) I'm tending to coast around the corners because of the rear end rotation when powering on. After about an 8+ minute practice run, there is a lot of rubber inside the body shell.
(5) NEW HIGH GRIP TRACK SETUP (end of day setup):
Drive: ________F=SpoolV3 + R=Diff
Ackermann: ___F=4.0
Shock Spring: __F=Pink + R=Silver (* tried F=Silver + R=Silver & tried F=Pink + R=Blue*)
Shock Oil: _____F=AE60 + R=AE35 + FullRebound + Foam (tried F=45 + R=35 *)
Shock Piston: __F+R=2hole,1.2mm
Shock Position:_F=3+2 + R=3+3 (* tried R=3+5 *)
Camber Link: ___F=2.0 + R=1.0 (* tried F=3.0 + R=0.0 etc *)
Camber: _______F=1.5 + R=1.5 (* tried F=2.0 + R=1.0 *)
Toe Block: _____F=1.5 + R=3.0
Toe: __________F=+0.5
Block Shims: ___F=2.0 + R=1.5 (* tried F=1.0 + R=1.5 *)
Wheelbase: ____F=2.0_0.5 + R=2.0_0.5 + R(hub)=2.0_0.5
Swaybar: ______F=1.4 + R=1.2
Swaybar Gap: __F=1.0 + R=2.0
Downstops: ____F=9.0 + R=9.0 (* tried F=8.5 + R=8.0 *)
Ride Height: ____F=5.5 + R=5.5 (* tried F=5.0 + R=5.5 *)
Middle Deck: ____Cut
Body: __________Mazda6
Tires: ___________Sorex32 + B_MediumInserts + SpeedmindRims
(6) I did not rotate the tires. The rear tires are looking ok, however, the front tires have worn through to the canvas in a couple of spots, and the inner rim of the front tires are split.
(7) The track is tight and technical, except for a sweeper onto the main straight (and then into a 180 degree hairpin at end of straight).
(8) I'm not 100% certain (so take this with a bit of scepticism) but I think the car gets through the corner entry and maybe middle but then rotates if slight braking or on power is applied. Might even be pushing mid-corner.
Any suggestions GREATLY appreciated.
Cheers
Another tricky set of questions. I have been running on a low grip track, and have just started running on a newly refurbished high grip track.
(1) The low grip track now seems under control, with a setup similar to Hara at RROC 2008.
(2) The new track is turning into a challenge for most drivers. The asphalt surface has been cleaned up, and the track has been repainted with a Boral anti-slip paint (like one might use around a swimming pool). Another club in Sydney used this paint about a year or so ago, and it worked out ok after a few months. Allegedly a high grip surface. It was painted with a paint roller, and apparently the stipples left by the roller actually create more grip for about the first 3 months, until they are worn down.
(3) The main problem is trying to get power down to the rear wheels. Unless the car is in a perfectly straight line, the rear end just rotates around under the mildest of power. My end of day setup seemed the best of a sub-optimal lot, but I don’t feel comfortable running an RC that is lower in the rear, than the front (I'm thinking there must be a better, more widely used setup to get around this challenge).
(4) I'm tending to coast around the corners because of the rear end rotation when powering on. After about an 8+ minute practice run, there is a lot of rubber inside the body shell.
(5) NEW HIGH GRIP TRACK SETUP (end of day setup):
Drive: ________F=SpoolV3 + R=Diff
Ackermann: ___F=4.0
Shock Spring: __F=Pink + R=Silver (* tried F=Silver + R=Silver & tried F=Pink + R=Blue*)
Shock Oil: _____F=AE60 + R=AE35 + FullRebound + Foam (tried F=45 + R=35 *)
Shock Piston: __F+R=2hole,1.2mm
Shock Position:_F=3+2 + R=3+3 (* tried R=3+5 *)
Camber Link: ___F=2.0 + R=1.0 (* tried F=3.0 + R=0.0 etc *)
Camber: _______F=1.5 + R=1.5 (* tried F=2.0 + R=1.0 *)
Toe Block: _____F=1.5 + R=3.0
Toe: __________F=+0.5
Block Shims: ___F=2.0 + R=1.5 (* tried F=1.0 + R=1.5 *)
Wheelbase: ____F=2.0_0.5 + R=2.0_0.5 + R(hub)=2.0_0.5
Swaybar: ______F=1.4 + R=1.2
Swaybar Gap: __F=1.0 + R=2.0
Downstops: ____F=9.0 + R=9.0 (* tried F=8.5 + R=8.0 *)
Ride Height: ____F=5.5 + R=5.5 (* tried F=5.0 + R=5.5 *)
Middle Deck: ____Cut
Body: __________Mazda6
Tires: ___________Sorex32 + B_MediumInserts + SpeedmindRims
(6) I did not rotate the tires. The rear tires are looking ok, however, the front tires have worn through to the canvas in a couple of spots, and the inner rim of the front tires are split.
(7) The track is tight and technical, except for a sweeper onto the main straight (and then into a 180 degree hairpin at end of straight).
(8) I'm not 100% certain (so take this with a bit of scepticism) but I think the car gets through the corner entry and maybe middle but then rotates if slight braking or on power is applied. Might even be pushing mid-corner.
Any suggestions GREATLY appreciated.
Cheers
To be honest... I never figured out how to make the back end stick better. I would loosen the front droop screws to allow more weight to transfer to the back. Maybe stand up the rear shocks and run a softer spring too. That will allow for more rear end grip typically, and take the swaybar off if that still doesn't help. Hopefully that helps a little bit.
-Korey
10-26-2009, 01:18 PM
You know, I remember driving on a track that was done on a tennis court. It had a sand impregnated paint, somewhat similar to what you are talking about. It felt like it always had awesome grip in the middle of the corner when it grips the abrasive surface, but then I think it actually RIPS the sand off the surface of the paint. After that it's like running on marbles.
To be honest... I never figured out how to make the back end stick better. I would loosen the front droop screws to allow more weight to transfer to the back. Maybe stand up the rear shocks and run a softer spring too. That will allow for more rear end grip typically, and take the swaybar off if that still doesn't help. Hopefully that helps a little bit.
-Korey
To be honest... I never figured out how to make the back end stick better. I would loosen the front droop screws to allow more weight to transfer to the back. Maybe stand up the rear shocks and run a softer spring too. That will allow for more rear end grip typically, and take the swaybar off if that still doesn't help. Hopefully that helps a little bit.
-Korey
(1) Thanks, I'll try your suggestions.
(2) I checked the manufacturers literature which states "Boral Surface Coat is a blend of bitumen emulsion, fillers and polymers ...".
It is smooth, so I'm moderately sure (?) its not using sand, so something else unusual is going on.
(3) After I got home, I thought about playing with droop and standing rear shocks up, so I kind of know where you are coming from. Lets see if I have the logic correct.
--(a) By standing the rear shocks up they will not be as progressive, therefore a softer rear will stay softer as it is compressed. A layed down shock will get harder as it is compressed, which would not help the situation of a loose rear end while cornering. Is this correct ?
?--(b) Front downstop screws less, to allow more weight transfer to the back under acceleration (as per your description).
(4) What about wider (or narrower) hex nuts?
If its wider, I could use a spacer.
Can you put the wider (or narrower) hex nuts just on one end of the car ?
?(5) Is there a possibility that on (say) a tight left hand corner, the car is rolling to the point where the rear left wheel is lifting off the track, and all the weight is going to the rear right wheel, causing the rear to rotate ?
? In this case, I would need to *reduce* the rear roll - or am I completely off the mark ?
?(6) After the practice day, I heard that one driver was using about 1mm droop - almost static weight distribution to minimise weight transfer.
Not sure about this ?
?Cheers
10-26-2009, 05:55 PM
10-26-2009, 07:14 PM
I have been having a few issues with my WCE Cyclone suddenly spinning out on tight left hand corners recently and cant seem to figure out what is doing it.
I've played with setup (droop, ride height, diff settings,tyres, shock oil and springs) and can't seem to solve it. The car will be fine for a few laps then all of a sudden will spin out on a particular corner. After a while of taking that corner slower i can go hard again.
I'm not sure if it is tyres as it happens with 28,32 and 36's.
Before it started happening I changed to the alloy diff and changed the front drive shafts from the older type to the newer 61088.
I also noticed that the rear front toe block seems to have some scratches on the left side it where the steering linkage may have been hitting it.
Now I need to find some time to test all these things out, but has anyone had similar issues and could have any of the above be causing it.
thanks
Dave
I've played with setup (droop, ride height, diff settings,tyres, shock oil and springs) and can't seem to solve it. The car will be fine for a few laps then all of a sudden will spin out on a particular corner. After a while of taking that corner slower i can go hard again.
I'm not sure if it is tyres as it happens with 28,32 and 36's.
Before it started happening I changed to the alloy diff and changed the front drive shafts from the older type to the newer 61088.
I also noticed that the rear front toe block seems to have some scratches on the left side it where the steering linkage may have been hitting it.
Now I need to find some time to test all these things out, but has anyone had similar issues and could have any of the above be causing it.
thanks
Dave