IRS drag racing part 2
IRS drag racing part 2
(OP)
This is where we left off. http://www.eng-tips.com/viewthread.cfm?qid=315042
This project has been on a break for a while and I'm starting to revisit it.
A little refresher. I'm trying to improve the geometry of a 2nd generation mr2 factory style IRS suspension for drag racing purposes.
There is strut, a trailing link, a lateral link and a toe arm. The lateral link goes from the subframe out to the lower ball joint and the trailing link attaches around the front area of the wheel well and interects through the lateral link via bushing.
This is a factory diagram... http://www.camskill.co.uk/smsimg/663/64188-68526-f...
http://www.bcmr2.com/matt/project/disassembly41.jp...
I cannot deviate from factory mounting points, although I could potentially make relocation bracketry that mounts at the factory spots.
I'm building all chromoly suspension arms with solid heim joints.
We've talked much in the past about camber and toe effects, but let's ignore that this time. At the moment I am only interested in the forward instant center/anti squat geometry in relationship to the center of gravity.
This is the design that my fabricator currently builds.
http://www.huxracing.com/#!MKII Tubular Control Arms/ccly
The arm with the ball joint hole is the lateral arm. Notice that he gets rid of the intersecting factory style bushing and solidly brackets the arms together.
I have a few questions.
How would one determine the instant center of a setup like this? Is it just a function of the imaginary line that would be drawn though the attachment points of the trailing link? Like on this fiero http://cliff.hostkansas.com/images/2011b/88_Fiero_...
Or, because my trailing link attaches to my lateral link, would the instant center be determined by way of the imaginary diagonal pivoting axis of the inner joint of the lateral link and the forward joint of the trailing link? Like an A-arm set at a 45*ish angle.
When these cars are lowered the trailing link sits, essentially, level to the ground and under accelleration, the rear joint is higher than the front. It seems to me that this is putting the I/C way out in front of the car at static ride height and underground, causing pro-squat, when launching, but since the trailing link is not 100% independant like the fiero diagram I showed earlier, I can't seem to wrap my head around this.
What I'm trying to do is build something that will have an adjustable instant center so I can play with the way the forces are transmitted to the body at the track for this reason. http://cliff.hostkansas.com/images/2011/Simplified...
This is a simple sketch of an idea I had, but I'm not sure if having an adjustable bracket in this way would actually do anything at all if the connection point of the two arms were assumed solid and unable to pivot because the angle of the dotted line does not change.
http://i785.photobucket.com/albums/yy138/fobangn/s...
Again, any help is greatly appreciated.
This project has been on a break for a while and I'm starting to revisit it.
A little refresher. I'm trying to improve the geometry of a 2nd generation mr2 factory style IRS suspension for drag racing purposes.
There is strut, a trailing link, a lateral link and a toe arm. The lateral link goes from the subframe out to the lower ball joint and the trailing link attaches around the front area of the wheel well and interects through the lateral link via bushing.
This is a factory diagram... http://www.camskill.co.uk/smsimg/663/64188-68526-f...
http://www.bcmr2.com/matt/project/disassembly41.jp...
I cannot deviate from factory mounting points, although I could potentially make relocation bracketry that mounts at the factory spots.
I'm building all chromoly suspension arms with solid heim joints.
We've talked much in the past about camber and toe effects, but let's ignore that this time. At the moment I am only interested in the forward instant center/anti squat geometry in relationship to the center of gravity.
This is the design that my fabricator currently builds.
http://www.huxracing.com/#!MKII Tubular Control Arms/ccly
The arm with the ball joint hole is the lateral arm. Notice that he gets rid of the intersecting factory style bushing and solidly brackets the arms together.
I have a few questions.
How would one determine the instant center of a setup like this? Is it just a function of the imaginary line that would be drawn though the attachment points of the trailing link? Like on this fiero http://cliff.hostkansas.com/images/2011b/88_Fiero_...
Or, because my trailing link attaches to my lateral link, would the instant center be determined by way of the imaginary diagonal pivoting axis of the inner joint of the lateral link and the forward joint of the trailing link? Like an A-arm set at a 45*ish angle.
When these cars are lowered the trailing link sits, essentially, level to the ground and under accelleration, the rear joint is higher than the front. It seems to me that this is putting the I/C way out in front of the car at static ride height and underground, causing pro-squat, when launching, but since the trailing link is not 100% independant like the fiero diagram I showed earlier, I can't seem to wrap my head around this.
What I'm trying to do is build something that will have an adjustable instant center so I can play with the way the forces are transmitted to the body at the track for this reason. http://cliff.hostkansas.com/images/2011/Simplified...
This is a simple sketch of an idea I had, but I'm not sure if having an adjustable bracket in this way would actually do anything at all if the connection point of the two arms were assumed solid and unable to pivot because the angle of the dotted line does not change.
http://i785.photobucket.com/albums/yy138/fobangn/s...
Again, any help is greatly appreciated.
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