Pertaining to autox, I have a CD5 with unusual rear instability issues which Honda93 can attest to. I realize there are many variables to consider to approach a solution. Ive considered F/R ride height as a possibility. Im a bit confused about what lifting or lowering the rear will do to the mannerisms of the car. Technically, if you adjust a spring to raise the car, it will be supporting more weight. However, I feel like it would make the car more tail happy despite the extra weight. Or, is that why it its that way, becuase of the added weight?? My gut tells me to lower the rear.......whats your input? Thanks.

 

The variable you left out is the dynamic camber curve of the suspension as it moves thru its travel.

Raising and lowering static ride height not only affects center of gravity but also affects how much and how quickly a wheel gains or loses dynamic camber. You are looking for a "sweat spot" where ride height best maximizes optimum Cg AND the best part of the dynamic camber curve.

That said, I don't know anyone who has actually gone to the trouble of measuring and plotting those camber curves and published their findings. There are a number of us talking about doing it, but so far everyone's just using trial and error to find optimum ride height and spring rates...

 

Are you saying that the camber arc that the wheel travels thru is not "consistent". Meaning, camber (in terms of degrees) is affected more in the last inch of suspension travel than the first inch?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by M23Accord &raquo;</TD></TR><TR><TD CLASS="quote">Are you saying that the camber arc that the wheel travels thru is not "consistent". Meaning, camber (in terms of degrees) is affected more in the last inch of suspension travel than the first inch?</TD></TR></TABLE>

I'm saying that camber (in terms of degrees) is affected differently in the last inch of suspension travel than the first inch? And then there are those pesky middle inches to consider...

 

What's a CD5? I'm not familiar with that one.

If you're having unpredictable instability, the first thing to check is the general condition of the rear suspension. Are all of the bushings in good condition? Are you sure nothing is binding?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Agent Smith &raquo;</TD></TR><TR><TD CLASS="quote">What's a CD5? I'm not familiar with that one.

If you're having unpredictable instability, the first thing to check is the general condition of the rear suspension. Are all of the bushings in good condition? Are you sure nothing is binding?
</TD></TR></TABLE>

ITs a 94-97 Accord.

Everything is new, even the hardware.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thawley &raquo;</TD></TR><TR><TD CLASS="quote">

I'm saying that camber (in terms of degrees) is affected differently in the last inch of suspension travel than the first inch? And then there are those pesky middle inches to consider...</TD></TR></TABLE>

Ahh, I see....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by M23Accord &raquo;</TD></TR><TR><TD CLASS="quote">Technically, if you adjust a spring to raise the car, it will be supporting more weight. However, I feel like it would make the car more tail happy despite the extra weight. Or, is that why it its that way, becuase of the added weight?? My gut tells me to lower the rear.......whats your input? Thanks. </TD></TR></TABLE>
wait a second. when you raise the rear or front of your car it changes the front rear weight balance. this may be part of the problem. if the rear is higher than the front then more weight its shifted to the front tires and reducing the grip on the rear tires. how does your balance sit right now? are all 4 corners dropped the same or is the front a little lower than the back maybe? if the back is just stepping out on you in corners then maybe try lowering the rear end a smidge or bringing the front up? this will redistribute some more weight and traction to your rear tires.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jeffhaut &raquo;</TD></TR><TR><TD CLASS="quote">
wait a second. when you raise the rear or front of your car it changes the front rear weight balance. this may be part of the problem. if the rear is higher than the front then more weight its shifted to the front tires and reducing the grip on the rear tires. how does your balance sit right now? are all 4 corners dropped the same or is the front a little lower than the back maybe? if the back is just stepping out on you in corners then maybe try lowering the rear end a smidge or bringing the front up? this will redistribute some more weight and traction to your rear tires.</TD></TR></TABLE>

Right, its what i was thinking

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jeffhaut &raquo;</TD></TR><TR><TD CLASS="quote">
wait a second. when you raise the rear or front of your car it changes the front rear weight balance. this may be part of the problem. if the rear is higher than the front then more weight its shifted to the front tires and reducing the grip on the rear tires.</TD></TR></TABLE>

Baloney.

The F/R weight balance does NOT change in any significant way by raising/lowering either end.

It DOES change if you raise or lower a single corner.

Here's a reference: http://www.nsxprime.com/FAQ/Pe...e.htm

In general, you know you have a corner balance problem when the balance is different turning one direction versus the other.

--Andy

 

What kind of camber are you running in the rear? A small change can make a big difference in how controllable the rear of the car is.

 

If the rear end feels too loose, there's something WRONG. Either it's the car or driver. Get that fixed first before you try to band-aid it by raising or lowering as the change will be relatively small.

Get an experienced driver to test your car and he should be able to get you in the right direction.

 

FWIW, we found that the difference in balance from raising or lowering the rear relative to the front is not relatively small. It's actually quite huge. 1/2 turn of the rear GC sleeves can make a very noticeable change in balance on our '89 Si in STS trim.

It is some combination of 3 things- more static negative camber when lower, camber curve, and roll centers, which someone once explained to me but I forgot it now. We found that higher in the rear is looser, lower is more stable assuming the front stays constant.

Also, if you have ever looked at cars that are not fully sorted, wildly divergent F/R ride heights are one of the things thats wrong and needs to be addressed, among other things.

Peter

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PoweredbyCamry &raquo;</TD></TR><TR><TD CLASS="quote">FWIW, we found that the difference in balance from raising or lowering the rear relative to the front is not relatively small. It's actually quite huge. 1/2 turn of the rear GC sleeves can make a very noticeable change in balance on our '89 Si in STS trim.</TD></TR></TABLE>

I believe Andy was referring to F/R weight balance. Unless you've got a flag pole with a weight at the end sticking out of the top of your car, adjusting the rake of the car won't move the center of gravity any significant amount.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MattP &raquo;</TD></TR><TR><TD CLASS="quote">

I believe Andy was referring to F/R weight balance. Unless you've got a flag pole with a weight at the end sticking out of the top of your car, adjusting the rake of the car won't move the center of gravity any significant amount. </TD></TR></TABLE>

Exactly. Weight balance.

I agree with Peter that F/R handling balance can be altered to varying degrees via changes in rake. I do this myself. As was mentioned before, though, you have to be careful that you are changing only one variable. On many cars, a change in ride height also changes camber and toe. So when testing, one must reset those other items to validate the change in handling due strictly to the rake change.

Interestingly, on an EF Civic, raising the rear ride height adds rake, reduces camber and has a very small effect on toe. So all of the variables move in the same direction from a handling balance point of view. So practically speaking, on that car its a very useful tool. I use it a lot.

Just don't expect the numbers on your corner-weight scales to change any when changing rake.

--Andy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Andy Hollis &raquo;</TD></TR><TR><TD CLASS="quote">Exactly. Weight balance.

I agree with Peter that F/R handling balance can be altered to varying degrees via changes in rake. I do this myself. As was mentioned before, though, you have to be careful that you are changing only one variable. On many cars, a change in ride height also changes camber and toe. So when testing, one must reset those other items to validate the change in handling due strictly to the rake change.

Interestingly, on an EF Civic, raising the rear ride height adds rake, reduces camber and has a very small effect on toe. So all of the variables move in the same direction from a handling balance point of view. So practically speaking, on that car its a very useful tool. I use it a lot.

Just don't expect the numbers on your corner-weight scales to change any when changing rake.

--Andy</TD></TR></TABLE>

Sorry in advance if this seems like a thread jack, but can anyone verify that raising or lowering the rear equally on both sides won't throw out a previously corner balanced car?

 

Actually I was replying to the post from Another Drew saying raising or lowering the rear is only a band aid and can only result in a very small change. My point was that front/rear ride height ratios that are very wildly different can be a real problem, just like any other.

I'm well aware that changing front or rear ride heights has no real impact on weight balance. I certainly know what Andy was speaking about. I was speaking of handling balance. Sorry for the confusion.

Peter

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TunerN00b &raquo;</TD></TR><TR><TD CLASS="quote">

Sorry in advance if this seems like a thread jack, but can anyone verify that raising or lowering the rear equally on both sides won't throw out a previously corner balanced car?</TD></TR></TABLE>

I do it all the time.

Also raise/lower both sides of the the front equally. I own scales. Nothing changes. Trust me.

--Andy

 

I have a 94 Honda accord LX with almost 200k.

The only mods are, a eibach prokit/tokico blues/tie bar/strut bar and sticky 205-50-16s.

on the auto-x, my car does tend to understeer, but I think a rear sway (which my car doesnt have) may help. My camber is about -1.2 in the rear, because of the drop, which I think helped a lot. Also the brake dive and weight transfer has been helped.

I think it may be driving technique. Please explain further.


Modified by carbnjunkie at 12:32 AM 12/13/2005

 

Actually going to a bigger rear sway will tend to make the car oversteer more. We usually run negative 2-2.5 derees of camber in the rear to keep the car from getting too loose.