New Sway Bar Option and Sway Bar Summary
01-27-2013, 11:54 AM
#27
Or not.
01-28-2013, 08:31 PM
#28
Following on from above, a 28.58mm bar with a 4.783 wall gives a raw rate of 1762.7, which is almost exactly the same as the 27mm whiteline bar and 1.58x stiffer than stock.
Assuming this is correct, then this is the bar I need :-)
At this point, that seems like a big assumption to make though!
Assuming this is correct, then this is the bar I need :-)
At this point, that seems like a big assumption to make though!
Your info emails on the PT RX-8 bar are inconsistent with previous info on that bar: 1 1/4" diameter, and 1/4 inch wall. One source: https://www.rx8club.com/wheels-tires...y-bars-109096/
another: Progress Technologies RX8 FRONT AntiSway Bar. for RX8 2004-2011
01-29-2013, 11:31 AM
#29
The weight with better scales is 9.1 +/- 0.15 lbs, which is more consistent with a .25" wall.
Your info emails on the PT RX-8 bar are inconsistent with previous info on that bar: 1 1/4" diameter, and 1/4 inch wall. One source: https://www.rx8club.com/wheels-tires...y-bars-109096/
another: Progress Technologies RX8 FRONT AntiSway Bar. for RX8 2004-2011
Your info emails on the PT RX-8 bar are inconsistent with previous info on that bar: 1 1/4" diameter, and 1/4 inch wall. One source: https://www.rx8club.com/wheels-tires...y-bars-109096/
another: Progress Technologies RX8 FRONT AntiSway Bar. for RX8 2004-2011
Actually knowing it is in the range of 3/16" to 1/4" is perhaps good enough. The 1/4" wall will only be ~12% stiffer than the 3/16" wall.
02-18-2013, 08:55 AM
#30
Well, thanks to the data from HiFlite I decided to order the PT miata front bar as combined with the adjustments it should be close enough for my needs. If there is any way to actaully measure the stiffness when it is on the car I'm all ears.
02-19-2013, 11:52 AM
#31
Thanks, I had some crazy ideas about jacking up one side of the car while on some scales, but I don't have easy access to any scales anyway. I think I'll just try driving it, see how I like the balance, and then adjust from there.
06-19-2013, 02:19 PM
#32
So this thread turned me on to the FCM calculator and I guess I have a couple of questions for the more experienced.
So above is a snippet of my results, and there are a few things that make me
. So reading some of their resources on the value each of those columns has, I was focusing a bit on the bounce frequency.
They mention that higher bounce frequencies can induce worse traction on the road when hitting bumps and that ideally, for a non-dedicated race vehicle, you want the frequencies to be about 1.8. Now my question is, how exactly does damping come into play? For example, we can see that my bounce frequency on the front is "high", now can that not be compensated for by increasing damping on the coilover, and furthermore, is that what one would ideally do to balance my setup more?
Also, how would one simulate running no rear bar? Putting a 0 in the rear sway size throws some of the numbers out of whack, whereas putting a 1 in the sway diameter and thickness seems to make more sense.
So above is a snippet of my results, and there are a few things that make me
. So reading some of their resources on the value each of those columns has, I was focusing a bit on the bounce frequency.They mention that higher bounce frequencies can induce worse traction on the road when hitting bumps and that ideally, for a non-dedicated race vehicle, you want the frequencies to be about 1.8. Now my question is, how exactly does damping come into play? For example, we can see that my bounce frequency on the front is "high", now can that not be compensated for by increasing damping on the coilover, and furthermore, is that what one would ideally do to balance my setup more?
Also, how would one simulate running no rear bar? Putting a 0 in the rear sway size throws some of the numbers out of whack, whereas putting a 1 in the sway diameter and thickness seems to make more sense.
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hufflepuff (11-27-2018)
07-10-2013, 05:11 PM
#33
They mention that higher bounce frequencies can induce worse traction on the road when hitting bumps and that ideally, for a non-dedicated race vehicle, you want the frequencies to be about 1.8. Now my question is, how exactly does damping come into play? For example, we can see that my bounce frequency on the front is "high", now can that not be compensated for by increasing damping on the coilover, and furthermore, is that what one would ideally do to balance my setup more?
Also, how would one simulate running no rear bar? Putting a 0 in the rear sway size throws some of the numbers out of whack, whereas putting a 1 in the sway diameter and thickness seems to make more sense.
Also, how would one simulate running no rear bar? Putting a 0 in the rear sway size throws some of the numbers out of whack, whereas putting a 1 in the sway diameter and thickness seems to make more sense.
Yes, if the damping is correct then it will help keep the tire in contact with the road.
On the sway bar settings, putting 0 in seems to work for me.
07-11-2013, 07:53 AM
#35
That calculator looks great blu3dragon. Is it available to the public?
I did not see wheelbase in the calculator though, and I think this will affect the ratio bounce frequency. The wheelbase will also affect the pitch frequency, but that isn't listed on your spreadsheet.
Do you mind sharing the equation that provides the ratio bounce frequency?
I did not see wheelbase in the calculator though, and I think this will affect the ratio bounce frequency. The wheelbase will also affect the pitch frequency, but that isn't listed on your spreadsheet.
Do you mind sharing the equation that provides the ratio bounce frequency?
07-11-2013, 09:09 AM
#37
Ok so here is my results with the NC sheet and after realizing how to put in solid bar data. Setup 1 is what i run daily, and what i run at autocross. Setup 2 is what I would have if I threw on 8K in the rear. I have a set of 8K swift springs sitting in my garage which is why i put that data there, just for comparison.
Last edited by paimon.soror; 07-11-2013 at 09:15 AM.
07-11-2013, 11:18 AM
#38
That calculator looks great blu3dragon. Is it available to the public?
I did not see wheelbase in the calculator though, and I think this will affect the ratio bounce frequency. The wheelbase will also affect the pitch frequency, but that isn't listed on your spreadsheet.
Do you mind sharing the equation that provides the ratio bounce frequency?
I did not see wheelbase in the calculator though, and I think this will affect the ratio bounce frequency. The wheelbase will also affect the pitch frequency, but that isn't listed on your spreadsheet.
Do you mind sharing the equation that provides the ratio bounce frequency?
07-11-2013, 11:27 AM
#39
Ok so here is my results with the NC sheet and after realizing how to put in solid bar data. Setup 1 is what i run daily, and what i run at autocross. Setup 2 is what I would have if I threw on 8K in the rear. I have a set of 8K swift springs sitting in my garage which is why i put that data there, just for comparison.
What bump stops are you using - are the bump stop rates you used correct?
I'm going to try and dial my balance (FRC) in this weekend which will be the first time I drive on track with coilovers and sway bars.
07-11-2013, 11:50 AM
#40
Thanks for sharing. How do you find the balance with your current setup?
What bump stops are you using - are the bump stop rates you used correct?
I'm going to try and dial my balance (FRC) in this weekend which will be the first time I drive on track with coilovers and sway bars.
What bump stops are you using - are the bump stop rates you used correct?
I'm going to try and dial my balance (FRC) in this weekend which will be the first time I drive on track with coilovers and sway bars.
I am not too sure what to put down for bump stop. I am using the ones that came with stance coilovers. I can't seem to find any data about their size or rate online.
2 questions:
1. based on what you were saying about about the bounce freq.... if i wanted more street comfort, I would be using the 11K/8K setup, and for a more aggresive track setup, I would stick with the 11K/6K?
2. Any idea what the front arm measurement would be on a swaybar on full soft?
edit: *derp* just noticed you had the full soft measurement above
07-11-2013, 12:06 PM
#41
Hrmm, interestingly enough, it looks like I should keep my rear bar on and my front on the softest hole as it will put my FRC closer to 69%? I am reading through the FCM tutorial and it comments on how a AutoX Miata shoots for about 65%
And even lower if you go with the MX5 Bar in the front, while keeping the PT rear bar.
And even lower if you go with the MX5 Bar in the front, while keeping the PT rear bar.
Last edited by paimon.soror; 07-11-2013 at 12:12 PM.
07-11-2013, 12:53 PM
#42
^So you are thinking 69% FRC since the RX8 has more power than the miata? I was actually aiming for 66% expecting that to give me slight understeer at the limit (the first row in my screenshot is my starting point this weekend...).
It is likely your bump stops are stiffer than 100 lbs/in since those are the softest ones FCM have. Stiffer bump stops will bring that FRC down. Given your experience and the unknown here, I would just use the spreadsheet as a guide to increase or lower FRC based on whether you want more front or rear grip.
In theory, you want to set the springs right first, and then tune FRC with the sway bars (and finally bump stops). So, I'd expect the stiffer 11k/8k setup to be better for racing/AX as long as the shocks can control those stiffer springs. If I were you I would try that, along with bars to keep the FRC where it works for you (11k/8k with the PT miata front bar and no rear bar should give you similar balance/FRC to your current setup) [EDIT: I meant miata front bar on softest setting. Stiffer bars reduce grip over mid corner bumps, so softer bars with stiffer springs is better for handling than softer springs with stiffer bars]
On your other question, I would expect the stiffer rear springs will have more effect on ride than the improved bounce frequency ratio. No way to know without trying it though
And yes, I measured (well more eyeballed) my front sway bar holes to be 15mm apart, with the furthest hole giving an arm length of ~200mm (leading me to trust Shaikh's 187mm measurement for the middle hole)
It is likely your bump stops are stiffer than 100 lbs/in since those are the softest ones FCM have. Stiffer bump stops will bring that FRC down. Given your experience and the unknown here, I would just use the spreadsheet as a guide to increase or lower FRC based on whether you want more front or rear grip.
In theory, you want to set the springs right first, and then tune FRC with the sway bars (and finally bump stops). So, I'd expect the stiffer 11k/8k setup to be better for racing/AX as long as the shocks can control those stiffer springs. If I were you I would try that, along with bars to keep the FRC where it works for you (11k/8k with the PT miata front bar and no rear bar should give you similar balance/FRC to your current setup) [EDIT: I meant miata front bar on softest setting. Stiffer bars reduce grip over mid corner bumps, so softer bars with stiffer springs is better for handling than softer springs with stiffer bars]
On your other question, I would expect the stiffer rear springs will have more effect on ride than the improved bounce frequency ratio. No way to know without trying it though
And yes, I measured (well more eyeballed) my front sway bar holes to be 15mm apart, with the furthest hole giving an arm length of ~200mm (leading me to trust Shaikh's 187mm measurement for the middle hole)
Last edited by blu3dragon; 07-11-2013 at 01:01 PM.
07-11-2013, 01:14 PM
#44
It is likely your bump stops are stiffer than 100 lbs/in since those are the softest ones FCM have. Stiffer bump stops will bring that FRC down. Given your experience and the unknown here, I would just use the spreadsheet as a guide to increase or lower FRC based on whether you want more front or rear grip.
In theory, you want to set the springs right first, and then tune FRC with the sway bars (and finally bump stops). So, I'd expect the stiffer 11k/8k setup to be better for racing/AX as long as the shocks can control those stiffer springs. If I were you I would try that, along with bars to keep the FRC where it works for you (11k/8k with the PT miata front bar and no rear bar should give you similar balance/FRC to your current setup) [EDIT: I meant miata front bar on softest setting. Stiffer bars reduce grip over mid corner bumps, so softer bars with stiffer springs is better for handling than softer springs with stiffer bars]
In theory, you want to set the springs right first, and then tune FRC with the sway bars (and finally bump stops). So, I'd expect the stiffer 11k/8k setup to be better for racing/AX as long as the shocks can control those stiffer springs. If I were you I would try that, along with bars to keep the FRC where it works for you (11k/8k with the PT miata front bar and no rear bar should give you similar balance/FRC to your current setup) [EDIT: I meant miata front bar on softest setting. Stiffer bars reduce grip over mid corner bumps, so softer bars with stiffer springs is better for handling than softer springs with stiffer bars]
Front bar on full soft
Rear bar on full soft
11K front
8K rear
200mm bump stops (set arbitrarily, only affects the last column)
07-11-2013, 01:18 PM
#45
^Unless you have a lot of understeer right now, I would guess you are going to get too much oversteer going that far! However, front bar on medium, or hard, with rear bar on soft will probably work well.
07-11-2013, 04:57 PM
#48