UCA variations
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From: Bahrain
UCA variations
Having just visited a used parts yard that imports direct from japan, i spent some time looking through the suspension bits they had. I noticed several variations of UCA there. Has anyone compared UCAs from different models before?
The reason i am asking is that my stock EG civic UCA when swapped right to left given a lot of positive castor.. and i was thinking of a way to reduce this.. one of the UCA i saw at the yard looked very very similar to the EG UCA but had less offset on the balljoint end.. Asked the yard guys and they said it came from a Honda SUV and most likely a CRV. Any thoughts??
The reason i am asking is that my stock EG civic UCA when swapped right to left given a lot of positive castor.. and i was thinking of a way to reduce this.. one of the UCA i saw at the yard looked very very similar to the EG UCA but had less offset on the balljoint end.. Asked the yard guys and they said it came from a Honda SUV and most likely a CRV. Any thoughts??
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From: good, USA
Re: UCA variations (BRN12345)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BRN12345 »</TD></TR><TR><TD CLASS="quote">Having just visited a used parts yard that imports direct from japan, i spent some time looking through the suspension bits they had. I noticed several variations of UCA there. Has anyone compared UCAs from different models before?
The reason i am asking is that my stock EG civic UCA when swapped right to left given a lot of positive castor.. and i was thinking of a way to reduce this.. one of the UCA i saw at the yard looked very very similar to the EG UCA but had less offset on the balljoint end.. Asked the yard guys and they said it came from a Honda SUV and most likely a CRV. Any thoughts??</TD></TR></TABLE>
more posive castor is not a bad thing. I actually preffer it
The reason i am asking is that my stock EG civic UCA when swapped right to left given a lot of positive castor.. and i was thinking of a way to reduce this.. one of the UCA i saw at the yard looked very very similar to the EG UCA but had less offset on the balljoint end.. Asked the yard guys and they said it came from a Honda SUV and most likely a CRV. Any thoughts??</TD></TR></TABLE>
more posive castor is not a bad thing. I actually preffer it
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Joined: Jun 2004
Posts: 7,539
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From: Sherman Oaks, CA, United States
Re: UCA variations (Team Bukkake Sucks!!!)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Team Bukkake Sucks!!! »</TD></TR><TR><TD CLASS="quote">
more posive castor is not a bad thing. I actually preffer it</TD></TR></TABLE>
Agreed. I'm running SPC caster adjustable UCAs, swapped left to right, and adjusted for max caster. About 1.5* from the swap, and another 1.5* of adjustment, resulting in 4* of caster on my DC2.
However, that still isn't very much caster compared to many many cars. Heck, my non-powersteering Triumph Spitfire has 5* of caster. I've considered trying to see if I could get an alignment shop to adjust the subframe for even more caster, but I have no clue how much adjustment room there really is there, and if doing so would put stress on anything.
more posive castor is not a bad thing. I actually preffer it</TD></TR></TABLE>
Agreed. I'm running SPC caster adjustable UCAs, swapped left to right, and adjusted for max caster. About 1.5* from the swap, and another 1.5* of adjustment, resulting in 4* of caster on my DC2.
However, that still isn't very much caster compared to many many cars. Heck, my non-powersteering Triumph Spitfire has 5* of caster. I've considered trying to see if I could get an alignment shop to adjust the subframe for even more caster, but I have no clue how much adjustment room there really is there, and if doing so would put stress on anything.
Joined: Apr 2002
Posts: 164
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From: Ashburn, va, us
Caster adjustment
I have tried to equalize my EG caster by shifting the subframe- I found no change from it. I did this while the car was settled on the alignment rack w/ sensors hooked up, its POSSIBLE that the reason I didnt find any help there is due to the car NOT being jacked up. This was the case on an S4 i worked on that had been wrecked. I had a serious pry bar and good places to pry however with the civic and did not w/ the audi. The process of jacking the car up w/o the live measurement (no alignment machine hooked up) and guessing where to set the subframe would take a long time of repeated trial and error to get it right. You could just try to maximize caster, then equalize it with another method while on the alignment rack.
Most people desire maximum positive caster. I see all kinds of cars factory alignment specs, as well as what many racers want me to dial in. Pretty much always more is better. It will help a self centered feel in the steering as well as generate negative camber to the outside tire on turns. Well handling Macphereson strut cars (M3, 911s, 240sx) usually have 5-7 degrees. Lotus Elise/Exige has 3~4, 300zx (z32) and many benz with upper and lower arms up front have over NINE degrees.
Im going to mimick the Elise caster adjustment method. I have poly in the UCA, and will shave the bushing on either side, and use washers to make up the amount of bushing removed, this way I can offset the upper arm fore and aft to some degree- im guessing 1 degree max. A good way to equalize at least.
People also will add shims b/w the two parts of the front LCA. This will work well with sperical bearing or stock inboard LCA bushings, but maybe not so well with poly. I haven't experimented with this on my car, but my friends H4 car was set that way at one point. Probably not a whole lot to gain there, but to equalize side to side, or trying to get every little bit possible it might be worth while.
-
Most people desire maximum positive caster. I see all kinds of cars factory alignment specs, as well as what many racers want me to dial in. Pretty much always more is better. It will help a self centered feel in the steering as well as generate negative camber to the outside tire on turns. Well handling Macphereson strut cars (M3, 911s, 240sx) usually have 5-7 degrees. Lotus Elise/Exige has 3~4, 300zx (z32) and many benz with upper and lower arms up front have over NINE degrees.
Im going to mimick the Elise caster adjustment method. I have poly in the UCA, and will shave the bushing on either side, and use washers to make up the amount of bushing removed, this way I can offset the upper arm fore and aft to some degree- im guessing 1 degree max. A good way to equalize at least.
People also will add shims b/w the two parts of the front LCA. This will work well with sperical bearing or stock inboard LCA bushings, but maybe not so well with poly. I haven't experimented with this on my car, but my friends H4 car was set that way at one point. Probably not a whole lot to gain there, but to equalize side to side, or trying to get every little bit possible it might be worth while.
-
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Joined: Mar 2004
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From: IL, USA
Re: Caster adjustment (EG8steve)
I would not go so far as to say more is always better. This was a pretty interesting read that someone brought up on the Evo forums, regarding caster and some of it's lesser known downsides...
http://www.ground-control.com/gctalk5.htm
http://www.ground-control.com/gctalk5.htm
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Joined: Jul 2005
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From: good, USA
Re: Caster adjustment (PIC Performance)
Yes the article is true but they are speaking for a rwd scenario.
I am sure everyone racing and dialing in there alignment knows that everything has a trade off. to much of one thing would almost always have at least one negative effect. The key is to find that fine line of balance the driver is comfortable with.
To reference the artice: What occurs with extra ("too much") caster is that more and more weight is transferred off of the outside front and inside rear tires, while this may at first sound good because taking the load off the outside front CAN be good, the reality is that the outside rear tire will be doing too much work in the middle of the turn, so steps then taken to alleviate this will cause a corner entry push. Additionally, on any rear wheel drive car the inside rear tire will be light and won't come off the corners well. Remember we're talking about a well balanced car here, not a car where this extra caster covers up a sway bar or spring problem.
we all know this is not a bad thing in an ff racecar. It would give us better rotation mid corner, and we dont have to worry about spinning the rear tires coming out of a turn
I am sure everyone racing and dialing in there alignment knows that everything has a trade off. to much of one thing would almost always have at least one negative effect. The key is to find that fine line of balance the driver is comfortable with.
To reference the artice: What occurs with extra ("too much") caster is that more and more weight is transferred off of the outside front and inside rear tires, while this may at first sound good because taking the load off the outside front CAN be good, the reality is that the outside rear tire will be doing too much work in the middle of the turn, so steps then taken to alleviate this will cause a corner entry push. Additionally, on any rear wheel drive car the inside rear tire will be light and won't come off the corners well. Remember we're talking about a well balanced car here, not a car where this extra caster covers up a sway bar or spring problem.
we all know this is not a bad thing in an ff racecar. It would give us better rotation mid corner, and we dont have to worry about spinning the rear tires coming out of a turn
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Joined: Jun 2004
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From: Sherman Oaks, CA, United States
Re: Caster adjustment (EG8steve)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG8steve »</TD></TR><TR><TD CLASS="quote">
People also will add shims b/w the two parts of the front LCA. This will work well with sperical bearing or stock inboard LCA bushings, but maybe not so well with poly. I haven't experimented with this on my car, but my friends H4 car was set that way at one point. Probably not a whole lot to gain there, but to equalize side to side, or trying to get every little bit possible it might be worth while.
</TD></TR></TABLE>
I have the Whiteline "Caster Kit", but not installed. It is longer LCA bolts, and shims to put between the 2 halves. I believe it cost me $35.
However, I have heard 2 horror stories from the only 2 people I have even known to have installed this kit. Apparently, they've both broken the Whiteline supplied bolts while on track. Since the LCA halves won't sit perfectly flush after adding shims, thinner bolts are needed to fit through the mis-aligned holes, which are supplied in the kit.
I'm also fairly sure that the kit would not be legal for ST* class autocross, which is why I never installed it.
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.
People also will add shims b/w the two parts of the front LCA. This will work well with sperical bearing or stock inboard LCA bushings, but maybe not so well with poly. I haven't experimented with this on my car, but my friends H4 car was set that way at one point. Probably not a whole lot to gain there, but to equalize side to side, or trying to get every little bit possible it might be worth while.
</TD></TR></TABLE>
I have the Whiteline "Caster Kit", but not installed. It is longer LCA bolts, and shims to put between the 2 halves. I believe it cost me $35.
However, I have heard 2 horror stories from the only 2 people I have even known to have installed this kit. Apparently, they've both broken the Whiteline supplied bolts while on track. Since the LCA halves won't sit perfectly flush after adding shims, thinner bolts are needed to fit through the mis-aligned holes, which are supplied in the kit.
I'm also fairly sure that the kit would not be legal for ST* class autocross, which is why I never installed it.
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.
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From: good, USA
Re: Caster adjustment (Team Bukkake Sucks!!!)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TunerN00b »</TD></TR><TR><TD CLASS="quote">
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Team Bukkake Sucks!!! »</TD></TR><TR><TD CLASS="quote">
I am sure everyone racing and dialing in there alignment knows that everything has a trade off. to much of one thing would almost always have at least one negative effect. The key is to find that fine line of balance the driver is comfortable with.
</TD></TR></TABLE>
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Team Bukkake Sucks!!! »</TD></TR><TR><TD CLASS="quote">
I am sure everyone racing and dialing in there alignment knows that everything has a trade off. to much of one thing would almost always have at least one negative effect. The key is to find that fine line of balance the driver is comfortable with.
</TD></TR></TABLE>
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Joined: Aug 2003
Posts: 140
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From: OR, USA
Re: Caster adjustment (TunerN00b)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TunerN00b »</TD></TR><TR><TD CLASS="quote">
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.</TD></TR></TABLE>
I've swapped the left/right Upper Control arms before and after I found out what bumpsteer was I realized how much I screwed up my car. Unfortunately, when you add caster to the EG honda you also royally screw up the bumpsteer curve, which doesn't sound important until you realize how important minimizing bumpsteer is. I was having a lot of problems with snap oversteer and I finally realized that it's the bumpsteer that's creating it. Also, the car felt really nervous on rough roads, but I rode like this for years until I finally confronted my mistake and swapped the UCA's back.
Think about it, Honda went way out of their way to design almost perfect camber and bumpsteer curves in the EG/DC suspension, don't screw it up by swapping UCA.
Other things to consider. If you add caster by moving the top of the knuckle back (UCA adjustment), you'll be increasing Ackerman. Where as if you move the bottom of the knuckle forward (LCA adjustment), you'll decrease it. Changes made through control arm adjustments will move the tie rod ends in comparison to the steering rack (forward or back), and could effect bumpsteer.</TD></TR></TABLE>
I've swapped the left/right Upper Control arms before and after I found out what bumpsteer was I realized how much I screwed up my car. Unfortunately, when you add caster to the EG honda you also royally screw up the bumpsteer curve, which doesn't sound important until you realize how important minimizing bumpsteer is. I was having a lot of problems with snap oversteer and I finally realized that it's the bumpsteer that's creating it. Also, the car felt really nervous on rough roads, but I rode like this for years until I finally confronted my mistake and swapped the UCA's back.
Think about it, Honda went way out of their way to design almost perfect camber and bumpsteer curves in the EG/DC suspension, don't screw it up by swapping UCA.
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Joined: Jun 2004
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From: Sherman Oaks, CA, United States
Re: Caster adjustment (ginsu2k)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ginsu2k »</TD></TR><TR><TD CLASS="quote">
Think about it, Honda went way out of their way to design almost perfect camber and bumpsteer curves in the EG/DC suspension, don't screw it up by swapping UCA. </TD></TR></TABLE>
But we already screw it up all the time. We lower the cars, changing the toe curve and bumpsteer Honda had originally designed into the stock suspension.
Heck, even a camber adjustable UCA will radically change the camber curve, because it changes the UCA total length (pivot point to balljoint) compared to the LCA. The more static camber you dial in, the more aggressive the camber curve under compression becomes. Alternatively decreasing static camber with the kit will make your camber curve worse.
Even more fun, is that changing the UCA length changes the UCA angle (without changing the LCA angle), which changes the instant center and roll center locations. Of course, lowering also changes roll center location, but how many of us ever consider where it actually is, or how our changes affect it? Really, I don't even know what the "best" location would be for it, even if I did bother to calculate it's location.
Now, I'm no suspension engineer. But considering how much we actually change with only minor adjustments to our suspensions, we all need to think like them on some levels. And if we are willing to change things, to not be afraid of trial and error.
Think about it, Honda went way out of their way to design almost perfect camber and bumpsteer curves in the EG/DC suspension, don't screw it up by swapping UCA. </TD></TR></TABLE>
But we already screw it up all the time. We lower the cars, changing the toe curve and bumpsteer Honda had originally designed into the stock suspension.
Heck, even a camber adjustable UCA will radically change the camber curve, because it changes the UCA total length (pivot point to balljoint) compared to the LCA. The more static camber you dial in, the more aggressive the camber curve under compression becomes. Alternatively decreasing static camber with the kit will make your camber curve worse.
Even more fun, is that changing the UCA length changes the UCA angle (without changing the LCA angle), which changes the instant center and roll center locations. Of course, lowering also changes roll center location, but how many of us ever consider where it actually is, or how our changes affect it? Really, I don't even know what the "best" location would be for it, even if I did bother to calculate it's location.
Now, I'm no suspension engineer. But considering how much we actually change with only minor adjustments to our suspensions, we all need to think like them on some levels. And if we are willing to change things, to not be afraid of trial and error.
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Joined: Mar 2003
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From: Pleasanton, Ca
Re: Caster adjustment (TunerN00b)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TunerN00b »</TD></TR><TR><TD CLASS="quote">I have the Whiteline "Caster Kit", but not installed. It is longer LCA bolts, and shims to put between the 2 halves. I believe it cost me $35.
However, I have heard 2 horror stories from the only 2 people I have even known to have installed this kit. Apparently, they've both broken the Whiteline supplied bolts while on track. Since the LCA halves won't sit perfectly flush after adding shims, thinner bolts are needed to fit through the mis-aligned holes, which are supplied in the kit.</TD></TR></TABLE>
Make that three people. I tired the kit and it failed on me! Made for an interesting lap. I would not suddest any one to use that kit.
However, I have heard 2 horror stories from the only 2 people I have even known to have installed this kit. Apparently, they've both broken the Whiteline supplied bolts while on track. Since the LCA halves won't sit perfectly flush after adding shims, thinner bolts are needed to fit through the mis-aligned holes, which are supplied in the kit.</TD></TR></TABLE>
Make that three people. I tired the kit and it failed on me! Made for an interesting lap. I would not suddest any one to use that kit.
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