View Full Version : Rain setups
wepsbee
10-01-2009, 10:02 AM
Well it looks like we will be able to experience some wonderful rain racing at LRP. A setup question? Disconnecting the rear sway bar, installing rain tires are obvious rain setup changes, what about the shock/struts? Soften all, just fronts, just backs, I am not clear on the physics of these adjustments. Some insight would be appreciated.
quadzjr
10-01-2009, 10:59 AM
on what you setup and why is a matter of preference. Typical you will want to soften the car up in general. To allow for more wieght transfer, slower. IT is all about maintaining static friction as long as possible. If your car is already bad with understear or overstear you can correct by softening one of the other just like you can in the dry. If you want to get even more in depth you can run softer spring rates.
-This is all from a theoretical stand pointand and an enginering background.
PM me if you would like a mroe indepth explaniation.. I find that too often I can get wordy when explaining things, and find that it was not necessary.
Dan--If you get over-set-up for rain, you will be slow on a drying or dry track.
A full rain set-up would also require a change of springs to soften everything up further--not worth the risk.
Just get yourself the best set of rains possible--Hoosiers (either Wets or Dirt Stockers). Rear Bar can be disconnected quickly. Top adjustable struts are nice too.
Personally I'm a fan of "disconnect the rear bar" and throw on the rain tires. You can fiddle with the shocks and soften things up but I've never seen a real need to do so. Swapping springs seems redonkulously over-involved for club level racing. Too much chance of making the car worse than it would have been on the "regular" spring setup. All, IMO of course.
wepsbee
10-01-2009, 01:24 PM
on what you setup and why is a matter of preference. Typical you will want to soften the car up in general. To allow for more wieght transfer, slower. IT is all about maintaining static friction as long as possible. If your car is already bad with understear or overstear you can correct by softening one of the other just like you can in the dry. If you want to get even more in depth you can run softer spring rates.
-This is all from a theoretical stand pointand and an enginering background.
PM me if you would like a mroe indepth explaniation.. I find that too often I can get wordy when explaining things, and find that it was not necessary.
Dan--If you get over-set-up for rain, you will be slow on a drying or dry track.
A full rain set-up would also require a change of springs to soften everything up further--not worth the risk.
Just get yourself the best set of rains possible--Hoosiers (either Wets or Dirt Stockers). Rear Bar can be disconnected quickly. Top adjustable struts are nice too.
Personally I'm a fan of "disconnect the rear bar" and throw on the rain tires. You can fiddle with the shocks and soften things up but I've never seen a real need to do so. Swapping springs seems redonkulously over-involved for club level racing. Too much chance of making the car worse than it would have been on the "regular" spring setup. All, IMO of course.
Thank you all for your help. I will disconnect the sway bar, I use Toyo's full tread as rains, I do have upper adjustable rear shocks and I do not have other springs. I am just getting the car to a point were I know what it will do in the dry so this will be new in the rain. I really cannot adjust too much as I will not be able to understand what is happening with all the changes. So I will make small changes and figure out a little at a time what is going on. Thanks for the starting points.
Depending on the rest of the setup and how comfortable you are in the rain, you could always soften the rear shocks to make it a little "safer" handling... not a "gotta do it" though, IMO.
RSTPerformance
10-01-2009, 06:36 PM
We did a lot of testing in the Rain a few years ago at Lime Rock... Put me on the Pole for ITB/ITS with an ITB car in the rain. The above suggestions are good but also dont forget, if you are running a lot of camber you may want to stand the tires up a bit and get rid of some of the camber. Sometimes it helps to get a bit of grip slowing down in a streaght line. Also you may not be "rolling onto the tire" as much in the rain especially if you don't soften the suspension, thus you don't need as much camber.
Raymond "just something to think about" Blethen
dyoungre
10-02-2009, 07:01 PM
If you can adjust your brake bias, you can actually ADD rear brake, since you won't be transferring as much weight. A little counter intuitive, but goes along with standing the tires back up.
RedMisted
10-07-2009, 03:24 PM
Just tuned in to this thread and found it interesting. I felt the need to chime in.
Last year, my car was pretty fast in the wet but it had a high performance street suspension on it. Now it's got stiffer race components all around and I don't expect to ever be as fast as I was in rainy conditions. In the dry, my new suspension is moderately stiff up front and full-soft in back. Unbelieveably, I do not have a rear sway bar. This is perhaps primarily because Ford did not think enough to build SN-95 V6 Mustangs with such a thing.
Question: In my case, would I be hurting myself in the wet if I softened the front dampers, or would that be inducing some oversteer?
lateapex911
10-07-2009, 04:17 PM
I'd think so. Softening the rear dampers might be a better idea.
Chris--Did you get the Car fixed after the Glen?
seckerich
10-07-2009, 05:01 PM
Just remember that you want to slow the movement of the chassis to retain grip. You will not be breaking as hard so there will be less transfer to provide front grip. Soften the rear rebound to help this. Leave the front rebound alone but soften the compression a small amount. Try to set your starting pressures close to optimum as you will not heat them up enough to grow. Do anything and everything to keep 4 tires on the track.
JeffYoung
10-07-2009, 05:13 PM
Jackstands.
dickita15
10-07-2009, 05:34 PM
Jackstands.
wuss:)
JeffYoung
10-07-2009, 05:45 PM
Totally.
lateapex911
10-07-2009, 05:49 PM
:shrug:
:rolleyes:
Lael Cleland
10-07-2009, 06:05 PM
The only thing I do is soften the rear shocks, drop some tire pressure, and run on the out side of the corners.. The Race line has oil coming up threw the assphalt and its a smother surface.The out side radius of a turn is rough aggregate, less oily, and there are little balls of used purple glue. In the rain w/itb rabbit I ran a 2.02, fastest dry was 1.54..(Midamerica motorplex)....both done on the same V700s.......Standing the wheel up would also help! I love racing in the rain!!!!!
seckerich
10-07-2009, 06:31 PM
It looks like a tent party when it rains in the southeast. :D
RedMisted
10-07-2009, 08:19 PM
Just remember that you want to slow the movement of the chassis to retain grip. You will not be breaking as hard so there will be less transfer to provide front grip. Soften the rear rebound to help this. Leave the front rebound alone but soften the compression a small amount. Try to set your starting pressures close to optimum as you will not heat them up enough to grow. Do anything and everything to keep 4 tires on the track.
Thing is, my dry set-up in the rear IS full-soft. So would one suggest that I increase the front rebound & leave the compression pretty much alone?
I'm thinking that I need to think about changing my front sway bar to a bigger one and putting a small bar in the rear (because, as already noted, I don't have a rear bar on my Mustang). Then when it rains, I can pull off the rear bar and get better handling balance.
RedMisted
10-07-2009, 08:23 PM
Chris--Did you get the Car fixed after the Glen?
Joe, I just got the car back yesterday. It's good to go. All the racket was from an exhaust system knocked a bit out of whack (by running over the curbs) and a damaged LF wheel bearing. Brakes were replaced and the car's wiring was redone. The total bill for the repairs was well under $1K. I was lucky the LF tire didn't puncture or else it coulda been ugly.
Thanks for asking.
Coming to the Harvest at NL?
Yes and you should go to the Pumpkin too!
RedMisted
10-08-2009, 09:05 AM
Yes and you should go to the Pumpkin too!
We'll see how much car and $$$ I have left for the Pumpkin!
wrcRS
11-09-2009, 07:35 PM
Thing is, my dry set-up in the rear IS full-soft. So would one suggest that I increase the front rebound & leave the compression pretty much alone?
I'm thinking that I need to think about changing my front sway bar to a bigger one and putting a small bar in the rear (because, as already noted, I don't have a rear bar on my Mustang). Then when it rains, I can pull off the rear bar and get better handling balance.
I try and stay away from rear sway bars on RWD cars. What kind of tire pressure do you run in the rear? When it rains, I run usually 5 psi less as a start.
Of course you can't adjust rear camber, its one thing I have considered doing for rain.
Not sure about less pressure as rain is generally associated with cool temps.
Accordingly, you may not want them that much lower.
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