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#1 SLM spring package w/out Bump Stops
slmnum8

Posts: 41
rating

10/13/2010 9:45 AM

What is the softest in the front you would run for BBSS but not running bumps? What about the rear...biggest RR? This would be for a coil-over 1750lb straight rail SLM.

On a side note, thanks to Rock and the other posters as there is a ton on info on here.....it's a great read!
 
#2 Re:SLM spring package w/out Bump Stops
slmnum8

Posts: 41
rating

10/13/2010 9:48 AM

Meant 2750lb lol
 
#3  
tucker16t

Posts: 255
rating

10/13/2010 10:37 AM

I have heard as low as 125 with bumps , maybe around 175 without. Depending on how high your starting frame height and sway bar.
 
#4  
Idive160

Posts: 42
rating

10/13/2010 12:11 PM

Depends on the size of the track, radius of the turns, the banking angle of the turns, and the banking of the straights.
 
#5  
tucker16t

Posts: 255
rating

10/13/2010 12:57 PM

Take it your not allowed to run bumpstops? As for the R/R spring, A good rule of thumb is half the rate as your sway bar. I tend to run slightly more , I guess whatever suites you. What size bar do you have (rate) ?
 
#6 Re:SLM spring package w/out Bump Stops
Rock

Posts: 2590
rating

10/13/2010 3:07 PM

Quote posted by slmnum8:What is the softest in the front you would run for BBSS but not running bumps? What about the rear...biggest RR? This would be for a coil-over 1750lb straight rail SLM.

On a side note, thanks to Rock and the other posters as there is a ton on info on here.....it's a great read!

I would not run a big RR. I do at some tracks but it is very difficult to work with to get it correct.
I would start with 275LF, 300RF, 225LR, 200RR.
Rear roll center around 10.1/2" 2" lower on frame side if you can get it,
in other words 11.1/2" rear end side and 9.1/2" frame side, just get as closed to that as you can.
 
#7  
slmnum8

Posts: 41
rating

10/13/2010 5:36 PM

It's a 3/8 mile ,low banked track, big bump off of 4. I've just never run bump stops and haven't even tried to begin too lol. Just curious how exterme I could try and get away with without them.
It's a 1 3/4" cup style bar (not sure what that rates to) Ran nuetral.
I was running
225LF 200RF
200LR 450RR

If I remember corerectly the rear roll center was 10 1/2 but with only 1/2" split, chassis side down.

Got wrecked the and had to sell the car...just thinkin ahaead for the next ride is all. Thanks again!
 
#8  
Rock

Posts: 2590
rating

10/13/2010 10:49 PM

The softest front springs I have been able to run and this was on a low banked track around 9 degrees, not sure. Without bump stops is 175LF, 200RF with the front raise up to 5.1/2" with very aggressive shocks.
This would depend on the driving style of the driver and your shock package.
Another thing, you need to go bigger or softer on your RR.
The range over a 250 through a 450 just doesn't work very good.
You need to keep the RR under a 250 or over a 500.
I would run either a 200RR or a 650RR.
 
#9 Re:
jedclampit

Posts: 59
rating

10/13/2010 10:58 PM

you never mentioned your cross weight...that makes a big difference on your setup...if there is big bumps...stay away from a big rr spring
 
#10  
tucker16t

Posts: 255
rating

10/14/2010 6:02 AM

Rock, So with my current setup 175 l/f 185 r/f 200l/r 400r/r with a 625 # bar, I should run a stiffer r/r or below 250 r/r?
 
#11  
johnpartridge

Posts: 64
rating

10/14/2010 8:59 AM

Rock helped us a little whith bumps a year ago... easiest thing in the world (for us) I would recomend it to anyone...It is actualy very easy to work with and understand..
 
#12 Re:
slmnum8

Posts: 41
rating

10/14/2010 9:47 AM

Where can I find out the sway bar conversion/rates?
 
#13 Re:
slmnum8

Posts: 41
rating

10/14/2010 9:54 AM

I think we were @ 53.5% cross or 54%.

I'm pretty aggressive into the corner as a driver. Car just never felt like it was down on the LF...I guess I was expecting it to feel like it was rotating around the LF with the BBSS.
 
#14 Re:
Rock

Posts: 2590
rating

10/14/2010 11:56 AM

Quote posted by slmnum8:Where can I find out the sway bar conversion/rates?
do you mean from a 1 piece to a 3 piece bar?
There is no conversion chart, you just need to know the rate of what you have and the rate of what you want.
There is a chart on the 3 piece bars on speedway engineering's web site,
www.1speedwayengineering.com
Make sure you check out the correct bar ends, different size and splines.
But remember everybody rates their bar different, some in inches and some in degrees.
 
#15  
Ronald01

Posts: 109
rating

10/14/2010 1:12 PM

I ran a flat 1/4 mile track with 175# LF and a 150# RF and had a lot of success. I was at a 4" LF and a 4 1/4" RF frame height. Never hit the track!
 
#16  
tucker16t

Posts: 255
rating

10/14/2010 5:41 PM

ronald 01 , Do you run bumpstops with those front rates? Also is that a soft conventional or bbss setup?
 
#17 Re:
Rock

Posts: 2590
rating

10/14/2010 8:16 PM

Quote posted by tucker16t:Rock, So with my current setup 175 l/f 185 r/f 200l/r 400r/r with a 625 # bar, I should run a stiffer r/r or below 250 r/r?
I would run a 200RR, you don't even have enough bar for the 400RR.
If your not going to run bump stop in the LR I would run a 225LR and a 200RR.
With bump stop in the LR a pair if 200's in the rear.
 
#18  
tucker16t

Posts: 255
rating

10/16/2010 7:29 AM

I value your advice Rock, But I thought the whole idea behind BBSS setup was to run a big r/r spring with low rear roll center to keep the l/f planted? If I run a 200 R/R I will be back to a soft conventional. I really like the way the car rotates now and it reacts a ton quicker with out all the rolling over and yawing back on the r/r. If I change wont the car go back to that? If so im going to a three piece bar with a higher rate, as I can not find a one piece any bigger.
 
#19 Re:
Ronald01

Posts: 109
rating

10/16/2010 8:03 AM

Quote posted by tucker16t:ronald 01 , Do you run bumpstops with those front rates? Also is that a soft conventional or bbss setup?

No bumpstops with those front rates. It is more of a soft conventional.
 
#20 Re:
Rock

Posts: 2590
rating

10/16/2010 10:48 AM

Quote posted by tucker16t:I value your advice Rock, But I thought the whole idea behind BBSS setup was to run a big r/r spring with low rear roll center to keep the l/f planted? If I run a 200 R/R I will be back to a soft conventional. I really like the way the car rotates now and it reacts a ton quicker with out all the rolling over and yawing back on the r/r. If I change wont the car go back to that? If so im going to a three piece bar with a higher rate, as I can not find a one piece any bigger.
I do run a big RR at some tracks, (a 650 with a 1175lb rate bar) but it won't work at all tracks.
If your car is working good at the track you run then by all means keep using it.
Good idea with the bar, there are so many rates to pick from.
 
#21  
balljoint_

Posts: 48
rating

10/29/2010 1:55 PM

keep in mind those 3 piece bars were designed for narrow cup cars with straight arms. Change the arms, change the rate.
 
#22 Re:SLM spring package w/out Bump Stops
slmnum8

Posts: 41
rating

10/25/2011 9:42 AM

Quote posted by Rock:Quote posted by slmnum8:What is the softest in the front you would run for BBSS but not running bumps? What about the rear...biggest RR? This would be for a coil-over 1750lb straight rail SLM.

On a side note, thanks to Rock and the other posters as there is a ton on info on here.....it's a great read!

I would not run a big RR. I do at some tracks but it is very difficult to work with to get it correct.
I would start with 275LF, 300RF, 225LR, 200RR.
Rear roll center around 10.1/2" 2" lower on frame side if you can get it,
in other words 11.1/2" rear end side and 9.1/2" frame side, just get as closed to that as you can.



Hey Rock,
Any chance you can post your email or email me at Sean@JHL2009.com so I can pick your brain about putting a car together with this type of soft-conventional setup?
Thanks!
 
#23  
Rock

Posts: 2590
rating

10/25/2011 2:20 PM

Sean,
I will in a bit.
Rock
 
#24 Re:
hellfire

Posts: 15
rating

10/25/2011 4:28 PM

Quote posted by Ronald01:I ran a flat 1/4 mile track with 175# LF and a 150# RF and had a lot of success. I was at a 4" LF and a 4 1/4" RF frame height. Never hit the track!

Generally a 5 degree twist (with a 12" arm) is the same as the rate at 1" of travel. These may sound like different ratings, but they are essentially the same. Just thought you might want to know.
 
#25  
Chris29

Posts: 326
rating

10/26/2011 10:15 PM

We ru a 175lf 200rf 4 1/2 inch ride height on a half mile 8 degrees banking with a 1 3/8 1 piece bar.
 
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