Ridetech OUT, 4 link Watts-link in.

[jetmech442]

Man, I'm so conflicted posting here with all the anger, but I’m going to share my experiences on my Cutlass in hopes of furthering a better path for this thread.


Below are my lessons learned/thoughts/suggestions from designing and running my 3link at the road course.
1) 100% antisquat is not great for either coming out of corners or going into braking zones. Mine is adjustable from 30-160AS in ~30 degree increments. The next time I go to the track I'm starting off on the 30% mark because I never want to experience that wicked wheel hop coming down from speed ever again. I'd rather have to be smoother on throttle out of turns than bring a duffel bag full of clean underwear.

2) The 3 link will offer more articulation than parallel 4 bars, and if you have to adjust it at the track, 1 bar is much easier to move and deal with than getting 2 the exact same length while maintaining pinion angle(especially in the grass on a hot day). That being sad, our cars don't travel a whole lot in the rear, so I'm not sure I'd ever notice the extra articulation available. But I wanted what I considered the best and so I went the 3 link route. My advice here is to devour every word Ron Sutton has ever posted here on this subject. His posts along with the others that have contributed and debated with him improved my understanding in a way that wouldn't have been possible just by reading Milken in the bubble bath while Katy Perry sang away my frustration.

3) I purposefully designed 3 settings into my frame mount on the lower arms so I can could change my rear steer to turn out (helps rotate for autocross, turn in (high speed stability for roadcourses), and neutral. to do this I loaded 270lbs of salt into the driver seat(a sad sight) and welded the brackets in the right height. so now I have an asymetric setup. great when it's just me, but when a friend or instructor is in the car, the setup is not perfect. I'm not going to say that I'm good enough to fully notice when the instructor is in the car...I'm sure I eventually will, but by that time hopefully I'm on my own. Ride height severely effects this so for now I am kinda stuck with my current size tire and tire choices.

4) You need to have the front roll center nailed down before you set the range for your watts link. The pivot of the watts will create the roll center and the line connecting those two will be a roll moment. some of the best money I ever spent on my cutlass was the Fays2 Watts link. It is frame mounted, which means the roll center doesn't migrate with the suspension movement. Stable roll centers are key contributors to predictable cars. In less than 3 minutes, I can throw the pivot to the top and have a stupid fun street car that throttle steers everywhere, drop it way down to the point of understeer, or...find just the right position for the track I'm at for best grip. Unless you know the front roll center though, you would need a ton of adjustment range to cover all the bases.

I hope this helps in your design considerations. I also hope that you can be part of a community of gearheads that don’t insult and flame posters/sponsors. I’ve bought my share of parts that didn’t work out as advertised. I realize with all my old ass frame and mods to the car that some stuff just doesn’t work out(especially if it’s a bolt on). When stuff like that happens, I pass it on to the next guy at a discount and get to work learning and making something myself if needed(kinda like you are doing).
Some of the best knowledge comes about from open debate and idea exchange between experienced racers/manufacturers in environments that encourage open dialogue, I hope this thread can become one of those examples.


-Scott

[dhutton]

Man, I'm so conflicted posting here with all the anger, but I’m going to share my experiences on my Cutlass in hopes of furthering a better path for this thread.


Below are my lessons learned/thoughts/suggestions from designing and running my 3link at the road course.
1) 100% antisquat is not great for either coming out of corners or going into braking zones. Mine is adjustable from 30-160AS in ~30 degree increments. The next time I go to the track I'm starting off on the 30% mark because I never want to experience that wicked wheel hop coming down from speed ever again. I'd rather have to be smoother on throttle out of turns than bring a duffel bag full of clean underwear.

2) The 3 link will offer more articulation than parallel 4 bars, and if you have to adjust it at the track, 1 bar is much easier to move and deal with than getting 2 the exact same length while maintaining pinion angle(especially in the grass on a hot day). That being sad, our cars don't travel a whole lot in the rear, so I'm not sure I'd ever notice the extra articulation available. But I wanted what I considered the best and so I went the 3 link route. My advice here is to devour every word Ron Sutton has ever posted here on this subject. His posts along with the others that have contributed and debated with him improved my understanding in a way that wouldn't have been possible just by reading Milken in the bubble bath while Katy Perry sang away my frustration.

3) I purposefully designed 3 settings into my frame mount on the lower arms so I can could change my rear steer to turn out (helps rotate for autocross, turn in (high speed stability for roadcourses), and neutral. to do this I loaded 270lbs of salt into the driver seat(a sad sight) and welded the brackets in the right height. so now I have an asymetric setup. great when it's just me, but when a friend or instructor is in the car, the setup is not perfect. I'm not going to say that I'm good enough to fully notice when the instructor is in the car...I'm sure I eventually will, but by that time hopefully I'm on my own. Ride height severely effects this so for now I am kinda stuck with my current size tire and tire choices.

4) You need to have the front roll center nailed down before you set the range for your watts link. The pivot of the watts will create the roll center and the line connecting those two will be a roll moment. some of the best money I ever spent on my cutlass was the Fays2 Watts link. It is frame mounted, which means the roll center doesn't migrate with the suspension movement. Stable roll centers are key contributors to predictable cars. In less than 3 minutes, I can throw the pivot to the top and have a stupid fun street car that throttle steers everywhere, drop it way down to the point of understeer, or...find just the right position for the track I'm at for best grip. Unless you know the front roll center though, you would need a ton of adjustment range to cover all the bases.

I hope this helps in your design considerations. I also hope that you can be part of a community of gearheads that don’t insult and flame posters/sponsors. I’ve bought my share of parts that didn’t work out as advertised. I realize with all my old ass frame and mods to the car that some stuff just doesn’t work out(especially if it’s a bolt on). When stuff like that happens, I pass it on to the next guy at a discount and get to work learning and making something myself if needed(kinda like you are doing).
Some of the best knowledge comes about from open debate and idea exchange between experienced racers/manufacturers in environments that encourage open dialogue, I hope this thread can become one of those examples.


-Scott

I agree, great post but all of Ron Sutton’s threads have been deleted. Sort of a shame, there was some good info to be gleaned from them.

Don