Opinions on LCA's
10-05-2009, 11:19 AM
#11
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Noise & Vibration - all sorts of little buzzes, whines, etc., will find their way from the tires (and driveshaft and axle gears!) into the car structure. Expect tire whine over grooved pavement to increase, for instance.
Harshness - expect to feel a much harsher impact as the rear wheels encounter certain shapes of short, sharp bumps. OE rubber and even poly bushings have a little "give" to them that takes some of the worst sting out of this. Note also that this beats up the rod ends, which can open up enough clearance in them so they rattle. At some point folks tend to replace the rod ends just to get rid of that annoyance. Most folks aren't serious enough to really want to keep replacing rod ends at regular intervals in their DD (4 x $35 or better for good quality rod ends does add up). For a dedicated track/autocross/dragstrip car, it's a little different.
A poly/rod end combination provides some NVH isolation and prolongs the life of the rod end at least somewhat.
Norm
Last edited by Norm Peterson; 10-05-2009 at 11:26 AM.
10-05-2009, 07:31 PM
#12
2nd Gear Member
Join Date: Jul 2009
Location: Canada
Posts: 157
As mentioned, it's an "NVH" issue, as in more of all three, vs what you'll personally tolerate long-term.
Noise & Vibration - all sorts of little buzzes, whines, etc., will find their way from the tires (and driveshaft and axle gears!) into the car structure. Expect tire whine over grooved pavement to increase, for instance.
Harshness - expect to feel a much harsher impact as the rear wheels encounter certain shapes of short, sharp bumps. OE rubber and even poly bushings have a little "give" to them that takes some of the worst sting out of this. Note also that this beats up the rod ends, which can open up enough clearance in them so they rattle. At some point folks tend to replace the rod ends just to get rid of that annoyance. Most folks aren't serious enough to really want to keep replacing rod ends at regular intervals in their DD (4 x $35 or better for good quality rod ends does add up). For a dedicated track/autocross/dragstrip car, it's a little different.
A poly/rod end combination provides some NVH isolation and prolongs the life of the rod end at least somewhat.
Norm
Noise & Vibration - all sorts of little buzzes, whines, etc., will find their way from the tires (and driveshaft and axle gears!) into the car structure. Expect tire whine over grooved pavement to increase, for instance.
Harshness - expect to feel a much harsher impact as the rear wheels encounter certain shapes of short, sharp bumps. OE rubber and even poly bushings have a little "give" to them that takes some of the worst sting out of this. Note also that this beats up the rod ends, which can open up enough clearance in them so they rattle. At some point folks tend to replace the rod ends just to get rid of that annoyance. Most folks aren't serious enough to really want to keep replacing rod ends at regular intervals in their DD (4 x $35 or better for good quality rod ends does add up). For a dedicated track/autocross/dragstrip car, it's a little different.
A poly/rod end combination provides some NVH isolation and prolongs the life of the rod end at least somewhat.
Norm
and i think the sphon parts sound the best so far for price in regards to that sweet del-sphere bushing setup they got going on...becuase BMR stuff is kind of pricey and steeda is as well.
thanks everyone!
Duggy
10-05-2009, 08:14 PM
#13
5th Gear Member
Join Date: Apr 2007
Location: CT
Posts: 2,612
yeah, like I said in my last post, I have BMR but if I were going to buy right now it would be spohns with poly / del spheres. AS for fix the wheel hop, the LCAs and a UCA would be better then the LCA and relocation brackets. The relocation brackets are more for correcting suspension geometry, or trying to optimise your traction on hard acceleration but using mechanical advantage to move weight to the rear of the car. The trade is say accelerating out of a corner, if your arms are set up to aggressive a angle, you can create some front end push. But lets be honest, who acelerates there mustang hard out of a corner and actualy wishes they had more traction on the front wheels then there back....
10-06-2009, 06:18 AM
#14
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
The trade is say accelerating out of a corner, if your arms are set up to aggressive a angle, you can create some front end push. But lets be honest, who acelerates there mustang hard out of a corner and actualy wishes they had more traction on the front wheels then there back....
So, loose in, not so loose in the middle, a little tight out is possible.
If you snap the throttle wide open as soon as you see the straight and are cornering pretty close to the limits of tire adhesion, it may not matter much what the roll steer % is.
Norm
Last edited by Norm Peterson; 10-06-2009 at 06:25 AM.
10-06-2009, 11:59 AM
#15
5th Gear Member
Join Date: Apr 2007
Location: CT
Posts: 2,612
Hey Norm, I think were saying the same thing. I jsut didnt elaborate that by front end push I was implying the lifting action of the front end and planting of the rear would want to make the straight rear axle drive more directly forward (towards the outside of the corner) while the front end is also having a harder time staying planted and pushing out instead of staying down and making the car steer through the corner. I had my mom grab a set of LCA brackets for her car (the BMR ones) and I intend to put them in the mid position for her stock height. She doesnt corner hard at all, and is more conserned with straight line performance.
10-06-2009, 01:29 PM
#16
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Nope. Two separate effects.
One is as you say, that when you apply power the nose rises and the front tires give up a little grip/run at slightly higher slip angles (this being an understeer effect).
The other involves actual steering of the rear axle as the car rolls in a turn, and can be either an understeer effect (as in all OE arrangements at OE ride height) or an oversteer effect. Normally, the installation of LCA relocating brackets on an unlowered car will change the axle steer from mild vehicle understeer toward or slightly into vehicle oversteer. If the car IS lowered, the end result is less understeerish that you get from doing the lowering by itself, but less oversteerish than if you do the relo brackets without doing the lowering.
The first is an effect on the car's heading as a consequence of feeding in power. The second has more to do with how hard you're cornering when you add that power.
Obviously, people are able to cope with a little oversteer from this effect. Best to wait until you're closer to going straight ahead before you add much throttle though.
Norm
One is as you say, that when you apply power the nose rises and the front tires give up a little grip/run at slightly higher slip angles (this being an understeer effect).
The other involves actual steering of the rear axle as the car rolls in a turn, and can be either an understeer effect (as in all OE arrangements at OE ride height) or an oversteer effect. Normally, the installation of LCA relocating brackets on an unlowered car will change the axle steer from mild vehicle understeer toward or slightly into vehicle oversteer. If the car IS lowered, the end result is less understeerish that you get from doing the lowering by itself, but less oversteerish than if you do the relo brackets without doing the lowering.
The first is an effect on the car's heading as a consequence of feeding in power. The second has more to do with how hard you're cornering when you add that power.
Obviously, people are able to cope with a little oversteer from this effect. Best to wait until you're closer to going straight ahead before you add much throttle though.
Norm
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