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4 link 9.75" rear 6.75 front spread?
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DRR Trophy
Picture of inferno camaro
posted
Wondering if this would work or if that spread is too narrow? I'm trying to get roughly 57 out 7 up for my IC and can do it 2 ways. 9.75 rear spread 2.5" above axle centerline and 6.75 front or I can do 11.75 rear 4.5" above axle centerline and 8 front spread both are very close to 57-58 out and 7 up. Will the car react differently depending which one I use and why?
It is currently 50 out 7 up but I'm switching to aluminum block so losing 110ish pounds off the front so would like to have another setting ready just in case I need a change.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
DRR S/Pro
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IC's and spreads are good to know but in the big picture, the bar angles are the most important tuning factor. You can have two or more setups with the same IC and the car won't react the same so why bother with them?
 
Posts: 1940 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
DRR Elite
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agreed and if the car was working with the iron block, I wouldn't change a thing.


O'IT!

Offering 1st hand experience and advice based on 3 decades of on track proven performance

"if you guys are so broke dyck you can't buy USA made parts you need to stay the fuc at home that's the bottomline" ----Tim McAmis



 
Posts: 12060 | Location: NJ | Registered: August 20, 2000Reply With QuoteReport This Post
DRR All Star
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Some folks only look at spread. I pretty much look at top and bottom bar angles. I do understand the influence that spread has even given the same bar angles. Less spread at the housing, the torque of the housing has a greater influence on the bars. Maybe I am missing the boat by not considering it with more importance. However, I never change anything based upon a hunch given other changes to the car. See what the car is doing and changed based upon actual data. Shock data. Driveshaft data. G meter data. Video recordings of the tire.


Foxtrot Juliet Bravo
 
Posts: 5964 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
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quote:
Originally posted by Bucky:
Some folks only look at spread. I pretty much look at top and bottom bar angles. I do understand the influence that spread has even given the same bar angles. Less spread at the housing, the torque of the housing has a greater influence on the bars. Maybe I am missing the boat by not considering it with more importance. However, I never change anything based upon a hunch given other changes to the car. See what the car is doing and changed based upon actual data. Shock data. Driveshaft data. G meter data. Video recordings of the tire.


Spread works like comparing a 1' torque wrench to a 2' one, you need twice the force on the shorter one to get the same torque. So the more spread you have at the axle housing end, all else equal, the less load the bars would carry to resist the torque applied. So in extreme circumstances/high power/torque combo's, moving this around could help. But in general, I'd say if you have your typical off the shelve four link brackets on your housing in a bracket application, the spread is likely OK. I'd also say that there is more to be gained here by using a good quality double adjustable shock along with a data logger with shock travel than you will ever get moving the spread around!
 
Posts: 1940 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
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The reason I'm trying to get another setting is the weight loss. I'm planning on trying it with the same settings it has but not sure how the weight loss will effect it. It has strange struts up front JRI sportsman rear shocks.
The bottom bar goes down 1/4" to the front in 19"
Thanks for the replies.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
DRR Sportsman
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If it goes stupid high why not just tighten the struts to offset it? easier than changing the 4 link
 
Posts: 579 | Location: nw ohio | Registered: November 20, 2001Reply With QuoteReport This Post



DRR All Star
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quote:
Originally posted by TOP38:
quote:
Originally posted by Bucky:
Some folks only look at spread. I pretty much look at top and bottom bar angles. I do understand the influence that spread has even given the same bar angles. Less spread at the housing, the torque of the housing has a greater influence on the bars. Maybe I am missing the boat by not considering it with more importance. However, I never change anything based upon a hunch given other changes to the car. See what the car is doing and changed based upon actual data. Shock data. Driveshaft data. G meter data. Video recordings of the tire.


Spread works like comparing a 1' torque wrench to a 2' one, you need twice the force on the shorter one to get the same torque. So the more spread you have at the axle housing end, all else equal, the less load the bars would carry to resist the torque applied. So in extreme circumstances/high power/torque combo's, moving this around could help. But in general, I'd say if you have your typical off the shelve four link brackets on your housing in a bracket application, the spread is likely OK. I'd also say that there is more to be gained here by using a good quality double adjustable shock along with a data logger with shock travel than you will ever get moving the spread around!


Pretty sure we said the same thing.


Foxtrot Juliet Bravo
 
Posts: 5964 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
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Picture of inferno camaro
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quote:
Originally posted by HR3377:
If it goes stupid high why not just tighten the struts to offset it? easier than changing the 4 link

Good advice thanks,
I'm going to tighten them some before I make a pass.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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I also do have a data logger but just basic for now. Has ds speed and O2's but not a g-meter or shock sensors but they can be added.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
DRR All Star
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What would be the objective 4 link wise to change for wheelies? Is the idea to hit the tire less hard and less quickly?


Foxtrot Juliet Bravo
 
Posts: 5964 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by Bucky:
Some folks only look at spread. I pretty much look at top and bottom bar angles. I do understand the influence that spread has even given the same bar angles. Less spread at the housing, the torque of the housing has a greater influence on the bars. Maybe I am missing the boat by not considering it with more importance. However, I never change anything based upon a hunch given other changes to the car. See what the car is doing and changed based upon actual data. Shock data. Driveshaft data. G meter data. Video recordings of the tire.


I can't imagine suppressing intuition. Intuition is a human survival mechanism in any competition to sharpen with experience. I'm the opposite, everything is a test of intuition.

Anytime you hear a racer say they accomplished x y z off the trailer, that's a result of intuition.


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Posts: 8834 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by inferno camaro:
quote:
Originally posted by HR3377:
If it goes stupid high why not just tighten the struts to offset it? easier than changing the 4 link

Good advice thanks,
I'm going to tighten them some before I make a pass.


Exactly, I had a Camaro that would wheelstand on command. I could set the car up to drive straight out or ride the rear bumper with a few clicks of the front shocks.
Set them tight for your first pass and then start adjusting from there.
Personally if your car is already working good I would not touch the 4 link until you find it is absolutely needed
 
Posts: 1981 | Location: On the the dark side now | Registered: April 30, 2010Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by inferno camaro:
quote:
Originally posted by HR3377:
If it goes stupid high why not just tighten the struts to offset it? easier than changing the 4 link

Good advice thanks,
I'm going to tighten them some before I make a pass.

Why?
Then you have no baseline.
Conjecture is a mistake when it comes to suspension tuning. Facts, and reaction to a change, whether it be positive or negative it starts with a baseline.
From there one change at a time.
 
Posts: 856 | Location: ft laud | Registered: September 02, 2004Reply With QuoteReport This Post



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Picture of inferno camaro
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quote:
Originally posted by Bucky:
What would be the objective 4 link wise to change for wheelies? Is the idea to hit the tire less hard and less quickly?

I was thinking may need hit tire less hard and slow down the transfer of weight. I'm not sure if that is right or wrong.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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quote:
Originally posted by Bad News:
quote:
Originally posted by inferno camaro:
quote:
Originally posted by HR3377:
If it goes stupid high why not just tighten the struts to offset it? easier than changing the 4 link

Good advice thanks,
I'm going to tighten them some before I make a pass.

Why?
Then you have no baseline.
Conjecture is a mistake when it comes to suspension tuning. Facts, and reaction to a change, whether it be positive or negative it starts with a baseline.
From there one change at a time.


I was just thinking I could tighten them to try and not have an un wanted wheelie first hit and then slowly loosen back to where they were at.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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The car worked pretty good on well prepped tracks but couldn't seem to keep the weight transferred on lesser prepped tracks. That was the main reason for going aluminum block. I plan to leave the 4-link as is and try it. I just want to know what setting to try if it needs a change.
Thanks for all the replies.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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Maybe post some starting line video of you car the way it's set up now?
 
Posts: 81 | Location: behind this screen | Registered: July 30, 2015Reply With QuoteReport This Post
DRR Elite
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inferno camaro, my suggestion is stop asking for opinions on the forums, you've spoken to Jerry Bickel already! You're hell bent on making change despite who tells you don't touch it. Get your new engine in the car, tighten the front shocks if you are worried about the front end rising too quickly and go from there. After that if you need help talk to your engine builder Phil who knows his way around a race car.


O'IT!

Offering 1st hand experience and advice based on 3 decades of on track proven performance

"if you guys are so broke dyck you can't buy USA made parts you need to stay the fuc at home that's the bottomline" ----Tim McAmis



 
Posts: 12060 | Location: NJ | Registered: August 20, 2000Reply With QuoteReport This Post
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quote:
Originally posted by 1320racer:
inferno camaro, my suggestion is stop asking for opinions on the forums, you've spoken to Jerry Bickel already! You're hell bent on making change despite who tells you don't touch it. Get your new engine in the car, tighten the front shocks if you are worried about the front end rising too quickly and go from there. After that if you need help talk to your engine builder Phil who knows his way around a race car.

Thanks for you opinion. Like I've said I will try it the way it is other than tightening the front end up. I can easily go back to the current setting just makes since to me to tighten it up to possibly not tear something up. I haven't talked to Jerry about this.
 
Posts: 295 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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