Suspension Upgrade Time: KW or Ohlins or FCM?
01-30-2016, 09:02 PM
#76
Water Foul
Thread Starter
I will write a full track review tomorrow, but here's a teaser. I topped my previous best consistent time on this track going this direction by almost exactly 2 full seconds and set a new personal top speed record (going into a 15mph wind no less)--besting my old personal record by 13mph. I'm shocked.
[Yeah. OK. Bad pun intended.]
.
[Yeah. OK. Bad pun intended.]
.
Last edited by Steve Dallas; 02-02-2016 at 09:37 PM. Reason: Looked at the data, corrected the numbers
02-01-2016, 09:31 PM
#77
don't forget about us
02-02-2016, 09:11 PM
#78
Water Foul
Thread Starter
Sorry. It has been a busy couple of days, and I have not had time to write a proper review. Here is what I can pen now in the time allowed.
On the 90 mile trip to the track, my opinion of the street manners of this suspension changed temporarily for the worse. Driving at 80mph on various [above average] North Texas highways was jarring until I had what should have been an obvious realization that I was on my track tires (RE-71Rs on this day to be consistent with my last outing in similar weather), which are not the most compliant. About halfway there, I decided I had too much rebound in the rear and decided to stop and back it off 3 clicks. That left me at 10 clicks from soft in the front and 7 in the rear. MUCH better. The rest of the trip there was quite nice, and the suspension was very comfortable. I was back to having a very positive opinion of the street characteristics of these coilovers. It wasn't as nice as it had been driving more slowly around town on more compliant tires, but it was still better than my PSS9s.
The surface on my home track is 15 year-old sealed and polished asphalt. It is a very slick track compared to most in all conditions. The asphalt is still in very good condition, however, and it is very smooth in most places, save for a few dips in key locations. Most turns are off-camber and quite challenging. There are about 200' of elevation changes throughout.
The conditions during my first track session were moderately cold at 50F, cloudy, and windy at 15mph from the west. After each of the first 5 laps, I tested the suspension to see how balanced it was. There was an obvious tendency toward oversteer that never improved. The track was so slick, that I never pushed more than about 70%--even after I got at least some heat in my tires. Other drivers reported the same.
Due to the oversteer I experienced in the first session, I dialed out 2 more clicks of rebound in the rear in an attempt to compensate. It helped during the second session, but the track was still too slick to open the car up much. I used the time to shake the rust off and explore the handling tendencies of the car a bit more.
[Aaaaaaaaaaaaaaaaaaaaah! The sun came out!]
The third session was more instructive. The sun came out and put some heat in the track. I was able to drive to about 85% of my normal attack, and the car handled very well. There was still more tendency toward oversteer than I like, but it was much more manageable than the skating I had done in the first 2 sessions.
At this point, I debated making sway bar changes to better balance the car, but decided to leave it alone and focus on the coilovers alone for this track day.
By session 4, the sun had been out for a few hours, the ambient temperature was in the upper 60s, and the track was fairly warm. I used the session to put the suspension through its paces. I tested every parameter I could think of and drove poorly on purpose in some instances to see how the suspension would behave. To say I was impressed would be an understatement. With just the modest increase in spring rates, the body roll I had previously fought was mostly eliminated. There is obviously still more than would be found in a fully track prepared car, but it is predictable and manageable. Bumps disappear as if they are not there. I played ping-pong with the curbs, and the shocks made them almost disappear. Braking on the newly painted rumble strips was once a precarious affair, but these shocks made that predictable. Turn-in was quick and confidence-inspiring. Bump travel was where I wanted it to be. There was no sign of bump steer like before. Wheel hop under hard braking was also virtually eliminated.
Session 5 presented a better opportunity for testing. The temperature had warmed to the mid 70s, and the track was in a good place. For this session, I decided to test more rebound front and rear, so I dialed both up 5 clicks. That makes 15 in the front and 10 in the rear. After 4 or 5 warm up laps, I was so confident in the car, that I decided to let it fly. And fly it did. Or maybe float. Fly sounds better. Anyway.
The first opportunity I had to notice this suspension allowing me to drive faster is on a turn called Ricochet. It really should be called Slingshot, because if you time it right, you feel like you have been shot out of one. Normally, I lift briefly near the top of the hill right before the turn to scrub speed down to 80mph, because that is as fast as I think I can safely take it and make the track out. I get back on it at the top of the hill to plant the rear end again before entering the turn. In this instance, I kept the pedal on the floor all the way through. I took the turn at > 90mph and gained 11mph over my usual speed by the end of the following short straight. Not bad.
A few turns later, there is a series of sweeping linked turns that can be driven by throttle steering with the steering wheel looked in place. Well, I normally throttle steer those turns. Now it seems I just floor it and let the newfound grip hold me down as I fly through them. Previously, I could shift to 4th right after the 3rd apex. Now I have to upshift just before the 1st apex or I will hit the rev limiter before I get to the 3rd apex. My top speed on the following straight increased by 7mph on average. I lose a little speed here due to the need to shift earlier. I need to think about my approach a little more, but I don't want to shift in the middle of the arc and upset the car. Hmmm...
The next turn is nicknamed Big Bend, because it is a big sweeper that is just over 90 degrees. It is a classic off-camber, late-apex turn. I normally dive into it at 70mph. Saturday afternoon, I was able to take it at 82mph on average. My top speeds for this track are all recorded on the following 1000ft straight. Because I was able to enter and exit the turn 10mph faster, I was able to improve from my usual 104mph to 117mph by the time I shat myself at the braking zone then right hand hairpin.
I won't bore you with the rest of it.
The data shows I improved my consistent average lap times by almost exactly 2 seconds. I also improved my top speed on the "long" straight by 13mph going against a 15mph wind. Those are some impressive results in my opinion. There are faster suspensions out there, but if you need a balance between track performance and street compliance, Ohlins DFV is a VERY good option. I track my car once a month on average, and I think this suspension strikes the perfect balance for that frequency.
Driving fast is all about driver skill and GRIP. Grip is accomplished through driver skill and happy tires. This Ohlins suspension keeps those tires happy. At the HPDE level, this suspension, some decent tires, and an otherwise good setup, puts the focus 100% back on the driver.
Bottom line: If you are considering Bilstein PSS9 coilovers for track use, it is absolutely worth the extra $800 to spring for Ohlins DFV instead. You will be astounded at their on-track performance and quite impressed at their street civility.
.
On the 90 mile trip to the track, my opinion of the street manners of this suspension changed temporarily for the worse. Driving at 80mph on various [above average] North Texas highways was jarring until I had what should have been an obvious realization that I was on my track tires (RE-71Rs on this day to be consistent with my last outing in similar weather), which are not the most compliant. About halfway there, I decided I had too much rebound in the rear and decided to stop and back it off 3 clicks. That left me at 10 clicks from soft in the front and 7 in the rear. MUCH better. The rest of the trip there was quite nice, and the suspension was very comfortable. I was back to having a very positive opinion of the street characteristics of these coilovers. It wasn't as nice as it had been driving more slowly around town on more compliant tires, but it was still better than my PSS9s.
The surface on my home track is 15 year-old sealed and polished asphalt. It is a very slick track compared to most in all conditions. The asphalt is still in very good condition, however, and it is very smooth in most places, save for a few dips in key locations. Most turns are off-camber and quite challenging. There are about 200' of elevation changes throughout.
The conditions during my first track session were moderately cold at 50F, cloudy, and windy at 15mph from the west. After each of the first 5 laps, I tested the suspension to see how balanced it was. There was an obvious tendency toward oversteer that never improved. The track was so slick, that I never pushed more than about 70%--even after I got at least some heat in my tires. Other drivers reported the same.
Due to the oversteer I experienced in the first session, I dialed out 2 more clicks of rebound in the rear in an attempt to compensate. It helped during the second session, but the track was still too slick to open the car up much. I used the time to shake the rust off and explore the handling tendencies of the car a bit more.
[Aaaaaaaaaaaaaaaaaaaaah! The sun came out!]
The third session was more instructive. The sun came out and put some heat in the track. I was able to drive to about 85% of my normal attack, and the car handled very well. There was still more tendency toward oversteer than I like, but it was much more manageable than the skating I had done in the first 2 sessions.
At this point, I debated making sway bar changes to better balance the car, but decided to leave it alone and focus on the coilovers alone for this track day.
By session 4, the sun had been out for a few hours, the ambient temperature was in the upper 60s, and the track was fairly warm. I used the session to put the suspension through its paces. I tested every parameter I could think of and drove poorly on purpose in some instances to see how the suspension would behave. To say I was impressed would be an understatement. With just the modest increase in spring rates, the body roll I had previously fought was mostly eliminated. There is obviously still more than would be found in a fully track prepared car, but it is predictable and manageable. Bumps disappear as if they are not there. I played ping-pong with the curbs, and the shocks made them almost disappear. Braking on the newly painted rumble strips was once a precarious affair, but these shocks made that predictable. Turn-in was quick and confidence-inspiring. Bump travel was where I wanted it to be. There was no sign of bump steer like before. Wheel hop under hard braking was also virtually eliminated.
Session 5 presented a better opportunity for testing. The temperature had warmed to the mid 70s, and the track was in a good place. For this session, I decided to test more rebound front and rear, so I dialed both up 5 clicks. That makes 15 in the front and 10 in the rear. After 4 or 5 warm up laps, I was so confident in the car, that I decided to let it fly. And fly it did. Or maybe float. Fly sounds better. Anyway.
The first opportunity I had to notice this suspension allowing me to drive faster is on a turn called Ricochet. It really should be called Slingshot, because if you time it right, you feel like you have been shot out of one. Normally, I lift briefly near the top of the hill right before the turn to scrub speed down to 80mph, because that is as fast as I think I can safely take it and make the track out. I get back on it at the top of the hill to plant the rear end again before entering the turn. In this instance, I kept the pedal on the floor all the way through. I took the turn at > 90mph and gained 11mph over my usual speed by the end of the following short straight. Not bad.
A few turns later, there is a series of sweeping linked turns that can be driven by throttle steering with the steering wheel looked in place. Well, I normally throttle steer those turns. Now it seems I just floor it and let the newfound grip hold me down as I fly through them. Previously, I could shift to 4th right after the 3rd apex. Now I have to upshift just before the 1st apex or I will hit the rev limiter before I get to the 3rd apex. My top speed on the following straight increased by 7mph on average. I lose a little speed here due to the need to shift earlier. I need to think about my approach a little more, but I don't want to shift in the middle of the arc and upset the car. Hmmm...
The next turn is nicknamed Big Bend, because it is a big sweeper that is just over 90 degrees. It is a classic off-camber, late-apex turn. I normally dive into it at 70mph. Saturday afternoon, I was able to take it at 82mph on average. My top speeds for this track are all recorded on the following 1000ft straight. Because I was able to enter and exit the turn 10mph faster, I was able to improve from my usual 104mph to 117mph by the time I shat myself at the braking zone then right hand hairpin.
I won't bore you with the rest of it.
The data shows I improved my consistent average lap times by almost exactly 2 seconds. I also improved my top speed on the "long" straight by 13mph going against a 15mph wind. Those are some impressive results in my opinion. There are faster suspensions out there, but if you need a balance between track performance and street compliance, Ohlins DFV is a VERY good option. I track my car once a month on average, and I think this suspension strikes the perfect balance for that frequency.
Driving fast is all about driver skill and GRIP. Grip is accomplished through driver skill and happy tires. This Ohlins suspension keeps those tires happy. At the HPDE level, this suspension, some decent tires, and an otherwise good setup, puts the focus 100% back on the driver.
Bottom line: If you are considering Bilstein PSS9 coilovers for track use, it is absolutely worth the extra $800 to spring for Ohlins DFV instead. You will be astounded at their on-track performance and quite impressed at their street civility.
.
Last edited by Steve Dallas; 02-02-2016 at 09:43 PM.
02-02-2016, 09:29 PM
#79
Water Foul
Thread Starter
One final note.
I did have that tendency toward too much oversteer all day. Session 6 was warmer, and things got greasy, which is where understeer tends to creep in. That never happened.
Actually, my car was previously so well balanced, that it would tend toward very slight oversteer at the beginning of a session, become perfectly neutral in the middle, and tend toward very slight understeer near the end of the session. That worked well in the HPDE format, because I normally have to pass a bunch of cars in the beginning (or be passed on some days), then have 6 or 8 laps of open track to lay down my best laps with a very neutral car, then do the passing thing again for the last few laps.
Given perfect traffic conditions, I normally like a car that is balanced toward slight understeer from the beginning, because it results in faster average corner speeds when trail braking is employed, but that is a whole other discussion. I digress.
To balance the car again, I have the following options. I intend to raise the car about 1/4" on average to bring the ride height up to approximately 13.5" all around. That will neutralize some oversteer. Afterwards, I can either move the front sway bar setting from medium to stiff or move the rear sway bar setting from stiff to soft.
I normally abhor too much sway bar, but I tacitly like the idea of stiffening the front bar, because that will give me a little less body roll. I noticed I am still wearing the outsides of my front tires a little more than I want to, and stiffening the front bar will help counteract that. If it turns out to be too much, I can try softening the rear instead, which appeals to my car setup instincts (rightly or wrongly).
I did have that tendency toward too much oversteer all day. Session 6 was warmer, and things got greasy, which is where understeer tends to creep in. That never happened.
Actually, my car was previously so well balanced, that it would tend toward very slight oversteer at the beginning of a session, become perfectly neutral in the middle, and tend toward very slight understeer near the end of the session. That worked well in the HPDE format, because I normally have to pass a bunch of cars in the beginning (or be passed on some days), then have 6 or 8 laps of open track to lay down my best laps with a very neutral car, then do the passing thing again for the last few laps.
Given perfect traffic conditions, I normally like a car that is balanced toward slight understeer from the beginning, because it results in faster average corner speeds when trail braking is employed, but that is a whole other discussion. I digress.
To balance the car again, I have the following options. I intend to raise the car about 1/4" on average to bring the ride height up to approximately 13.5" all around. That will neutralize some oversteer. Afterwards, I can either move the front sway bar setting from medium to stiff or move the rear sway bar setting from stiff to soft.
I normally abhor too much sway bar, but I tacitly like the idea of stiffening the front bar, because that will give me a little less body roll. I noticed I am still wearing the outsides of my front tires a little more than I want to, and stiffening the front bar will help counteract that. If it turns out to be too much, I can try softening the rear instead, which appeals to my car setup instincts (rightly or wrongly).
02-03-2016, 08:03 AM
#80
Great write-up, thanks for taking the time!
Glad you are enjoying the Ohlins.
Rather amazing you were going 10+mph faster in some corners and straights; same car, driver, track, tires. Wow.
I am no suspension guru, but the car changing from oversteer-neutral-understeer through the day tells me (again, I may be very wrong) the tires are suffering. You mention wearing the outside fronts a bit much. Would a bit more front camber help address both issues? Curious if you check tire temp across the tread width after a session.
Glad you are enjoying the Ohlins.
Rather amazing you were going 10+mph faster in some corners and straights; same car, driver, track, tires. Wow.
I am no suspension guru, but the car changing from oversteer-neutral-understeer through the day tells me (again, I may be very wrong) the tires are suffering. You mention wearing the outside fronts a bit much. Would a bit more front camber help address both issues? Curious if you check tire temp across the tread width after a session.
02-03-2016, 10:03 AM
#81
Water Foul
Thread Starter
The tires probably are suffering. The conventional wisdom is that the compound Bridgestone uses in these tires is targeted at autocross, and extended track sessions overheat them. The Internet is full of RE-71R behavior and tire wear weirdnesss reports. It is well known to be a strange tire. I run it anyway, because it has monster grip when happy--similar to R comps.
I have my negative camber maxed out. I monitor tire pressures and heat distribution very closely. Sway bar adjustments are the last arrow in the quiver, although this new suspension is much nicer to the tires than the PSS9 setup was. A street/track hybrid car is never going to be perfect. I just have to make the most of it and do the best that I can.
Focus will be fully back on the driver mod this season. According to my lap timer, my theoretical best time is nearly 4 seconds faster than what I am doing now. It isn't possible to actually achieve that, since it isn't possible to drive a perfect lap (especially with any consistency), but I probably have 2 or more seconds to shave off with this car before I reach its max potential.
.
I have my negative camber maxed out. I monitor tire pressures and heat distribution very closely. Sway bar adjustments are the last arrow in the quiver, although this new suspension is much nicer to the tires than the PSS9 setup was. A street/track hybrid car is never going to be perfect. I just have to make the most of it and do the best that I can.
Focus will be fully back on the driver mod this season. According to my lap timer, my theoretical best time is nearly 4 seconds faster than what I am doing now. It isn't possible to actually achieve that, since it isn't possible to drive a perfect lap (especially with any consistency), but I probably have 2 or more seconds to shave off with this car before I reach its max potential.
.
Last edited by Steve Dallas; 08-11-2016 at 08:17 AM.
02-03-2016, 10:05 AM
#82
As above, thanks for the write up. Very interesting.
I tend to get similar balance behavior:
a) less grip means a more tail happy car. I'm not sure if this is driver related, suspension loading related, or possibly a combination of both.
b) the balance changes as the track, or tires heat up. Typically I get more understeer as the track heats up, but this can also go the other way if I overheat my rear tires relative to the fronts (e.g. in traffic, carrying less speed in and trying to use more throttle out). I can mostly counteract this by adjusting tire pressures so balance stays even through a session.
I think your plan with regards to setup and countering the oversteer sounds good. I agree with the premise of less is more with regards to sway bars, but this is countered by the need to compromise spring rates for the track, so you do what you need to do...
The other thing to check is your alignment... sounds like you could use a little more front camber if it is possible to get that.
Very nice overall improvement though. Congratulations
I tend to get similar balance behavior:
a) less grip means a more tail happy car. I'm not sure if this is driver related, suspension loading related, or possibly a combination of both.
b) the balance changes as the track, or tires heat up. Typically I get more understeer as the track heats up, but this can also go the other way if I overheat my rear tires relative to the fronts (e.g. in traffic, carrying less speed in and trying to use more throttle out). I can mostly counteract this by adjusting tire pressures so balance stays even through a session.
I think your plan with regards to setup and countering the oversteer sounds good. I agree with the premise of less is more with regards to sway bars, but this is countered by the need to compromise spring rates for the track, so you do what you need to do...
The other thing to check is your alignment... sounds like you could use a little more front camber if it is possible to get that.
Very nice overall improvement though. Congratulations
Last edited by blu3dragon; 02-03-2016 at 10:08 AM.
03-20-2016, 07:11 PM
#84
Water Foul
Thread Starter
^ The R3 has a very capable suspension that can carry a person into advanced level HP driving to be sure. Upgrading mine to R3 specs certainly was an option, and it was one that I contemplated.
I remember the price for OEM R3 parts being about as high or higher than the Bilstein PSS9s I started with. Back then, I wanted ride height adjustability for corner balancing and thought I needed rebound adjustability. So, I went with the coilovers instead. That may or may not have been the right decision.
This time, I wanted to step up to as much of an elite suspension as possible within my budget of $2500. So far, I am loving Ohlins. I have never had happier tires.
IIRC, that comment was directed toward someone who is at the novice level of HPD or contemplating getting started. In that context, the R3 would delight that person for several years until he or she finally made it to the point of being able to push the car past its true limits.
Finally, there are other reasons to like the R3 over the GT for track use. It is lighter and has better Aero for starters.
I remember the price for OEM R3 parts being about as high or higher than the Bilstein PSS9s I started with. Back then, I wanted ride height adjustability for corner balancing and thought I needed rebound adjustability. So, I went with the coilovers instead. That may or may not have been the right decision.
This time, I wanted to step up to as much of an elite suspension as possible within my budget of $2500. So far, I am loving Ohlins. I have never had happier tires.
IIRC, that comment was directed toward someone who is at the novice level of HPD or contemplating getting started. In that context, the R3 would delight that person for several years until he or she finally made it to the point of being able to push the car past its true limits.
Finally, there are other reasons to like the R3 over the GT for track use. It is lighter and has better Aero for starters.
03-29-2016, 07:19 PM
#86
Water Foul
Thread Starter
It is far better than I expected on the street, considering the springs are 3x the stock rates. You can tell you are driving a sports car, but Ohlins really knows how to engineer a compliant ride. I am quite pleased with its street performance. Better than my old Bilsteins in that regard as well.
03-29-2016, 10:13 PM
#87
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Thanks for the write-up - I'm currently putting together an RX8 for track use and just discovered the rear shocks are blown. I've been tempted by the Ohlins before, but after reading through your thread I think I'll put an order in for a set...
08-11-2016, 05:32 AM
#88
Registered
The tires probably are suffering. The conventional wisdom is that the compound Bridgestone uses in these tires is targeted at autocross, and extended track sessions overheat them. The Internet is full of RE-71R behavior and tire wear weirdnesss reports. It is well known to be a strange tire. I run it anyway, because it has monster grip when happy--similar to R comps.
I have my negative camber maxed out. I monitor tire pressures and heat distribution very closely. Sway bar adjustments are the last arrow in the quiver, although this new suspension is much nicer to the tires than the PSS9 setup was. A street/track hybrid car is never going to be perfect. I just have to make the most of it and do the best that I can.
Focus will be fully back on the driver mod this season. According to my lap timer, my theoretical best time is nearly 6 seconds faster than what I am doing now. It isn't possible to actually achieve that, since it isn't possible to drive a perfect lap (especially with any consistency), but I probably have 4 or more seconds to shave off with this car before I reach its max potential.
.
I have my negative camber maxed out. I monitor tire pressures and heat distribution very closely. Sway bar adjustments are the last arrow in the quiver, although this new suspension is much nicer to the tires than the PSS9 setup was. A street/track hybrid car is never going to be perfect. I just have to make the most of it and do the best that I can.
Focus will be fully back on the driver mod this season. According to my lap timer, my theoretical best time is nearly 6 seconds faster than what I am doing now. It isn't possible to actually achieve that, since it isn't possible to drive a perfect lap (especially with any consistency), but I probably have 4 or more seconds to shave off with this car before I reach its max potential.
.
I'd look into offset control arm bushings to add negative front camber if you are wearing the outside edges.
08-11-2016, 08:29 AM
#89
Water Foul
Thread Starter
^ I know I can use offset bushings to stretch the negative camber, but I hesitate to do that, because I don't see myself tracking this car for more than a year or two longer. At that point, I would have to go back to regular bushings to achieve street camber again.
I'm also trying the Maxxis tire this fall. What I have seen at the track has me thinking it might wear more evenly in my setup. RE-71Rs truly are weird.
Another change I might mention, is I recently grabbed a free 12mm rear Miata bar for my 8. I have a little more tendency toward oversteer than I like, and I am hoping the Miata bar will get me where I want to be. I have the shocks adjusted about as perfectly as they can be at my home track, so it is time to play with the bars again. I am currently running a Progress Miata bar on the medium setting up front and my stock yellow dot bar in the rear. Changing the coilovers changed the balance of the car a bit more than I expected, to be honest. Using the online calculators with the limited data I have showed a change from slight understeer to moderate understeer. In reality, the change biased the car to medium oversteer. Swapping out the rear Progress Miata bar for the stock bar moved the needle in the right direction, but I would like to get back to slight understeer if I can.
When biased to slight understeer, the car will exhibit that understeer for the first 3 to 5 laps, then become neutral. After 8 to 10 laps, it will begin to exhibit slight oversteer, as things get greasy. That gives me the opportunity to practice with all 3 conditions every session, which I like. Interestingly, the slight understeer laps are the fastest, according to my Aim Solo.
I'm also trying the Maxxis tire this fall. What I have seen at the track has me thinking it might wear more evenly in my setup. RE-71Rs truly are weird.
Another change I might mention, is I recently grabbed a free 12mm rear Miata bar for my 8. I have a little more tendency toward oversteer than I like, and I am hoping the Miata bar will get me where I want to be. I have the shocks adjusted about as perfectly as they can be at my home track, so it is time to play with the bars again. I am currently running a Progress Miata bar on the medium setting up front and my stock yellow dot bar in the rear. Changing the coilovers changed the balance of the car a bit more than I expected, to be honest. Using the online calculators with the limited data I have showed a change from slight understeer to moderate understeer. In reality, the change biased the car to medium oversteer. Swapping out the rear Progress Miata bar for the stock bar moved the needle in the right direction, but I would like to get back to slight understeer if I can.
When biased to slight understeer, the car will exhibit that understeer for the first 3 to 5 laps, then become neutral. After 8 to 10 laps, it will begin to exhibit slight oversteer, as things get greasy. That gives me the opportunity to practice with all 3 conditions every session, which I like. Interestingly, the slight understeer laps are the fastest, according to my Aim Solo.
Last edited by Steve Dallas; 02-21-2017 at 05:35 PM.
08-11-2016, 01:18 PM
#91
Water Foul
Thread Starter
Nothing is set in stone, but I figure it will be time to move on to something else. Mine is still a really nice car that could be returned to touring duty for many years of future service.
08-11-2016, 01:24 PM
#92
Registered
I'm actually very surprised you ended up with such a loose car when the front roll couple is biased so far to the front. the rear springs are so soft compared to most other aftermarket setups... but I guess somehow it works!!
08-12-2016, 11:24 AM
#93
When biased to slight understeer, the car will exhibit that understeer for the first 3 to 5 laps, then become neutral. After 8 to 10 laps, it will begin to exhibit slight oversteer, as things get greasy. That gives me the opportunity to practice with all 3 conditions every session, which I like.
I've found my car gets that greasy feeling as the pressures go over 38-40psi, and letting the rear tires get there, while the fronts are a little lower does loosen things up a bit.
The other solution is less tread. That will stop the tires heating up so much.
08-12-2016, 11:32 AM
#94
Water Foul
Thread Starter
I do adjust my tire pressures throughout the day. On a hot day in Texas, a little greasy-ness is pretty normal. Options are to cool the car down for a lap or two or just go with it and have fun.
08-13-2016, 05:19 PM
#95
You can adjust the offset on the bushing to give you more camber, less camber, or the same camber as original. So don't let that concern stop you.
10-14-2016, 10:13 PM
#96
Water Foul
Thread Starter
Minor update. The 12mm bar moved the needle in the right direction and almost got me there. Some minor alignment changes plus an 11mm bar (also free!) put me almost exactly where I want to be again in terms of balance. I am now back to slight understeer, and my lap times are showing the improvement.
So, to summarize, I am running a Progress NC Miata bar up front set on medium and an OEM 11mm NC Miata bar in the rear. I have Flyin' Miata NC adjustable end links front and rear, set to zero preload when the suspension is at rest.
After playing around with the rebound settings on the shocks, I have found the lower end of the spectrum to be most appropriate for my home track. I am currently running 10 front and 12 rear. According to Penske's instructions for setting rebound, I have found the sweet spot on this track. Of course, now that it is getting cooler...
.
So, to summarize, I am running a Progress NC Miata bar up front set on medium and an OEM 11mm NC Miata bar in the rear. I have Flyin' Miata NC adjustable end links front and rear, set to zero preload when the suspension is at rest.
After playing around with the rebound settings on the shocks, I have found the lower end of the spectrum to be most appropriate for my home track. I am currently running 10 front and 12 rear. According to Penske's instructions for setting rebound, I have found the sweet spot on this track. Of course, now that it is getting cooler...
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Last edited by Steve Dallas; 02-21-2017 at 05:37 PM.
10-23-2016, 05:10 PM
#99
Registered
BIG thank you
Steve Dallas:
A big thank you for your thoughtful and informative write up(s). You have documented your thoughts and experiance, and by doing so, have provided a very valuable tool for my own analysis. I realize this takes quite a bit of your time to do, and I appricate your efforts.
Thanks again!
A big thank you for your thoughtful and informative write up(s). You have documented your thoughts and experiance, and by doing so, have provided a very valuable tool for my own analysis. I realize this takes quite a bit of your time to do, and I appricate your efforts.
Thanks again!
02-21-2017, 09:14 AM
#100
this was very informative.
if I want to save some dead presidents and upgrade my stock suspension ( I have hotchkis bars f/r) on my S2 used mainly for track duty - so street comfort is not an issue would I be better served with :
1. koni shocks and some high rate springs - how much spring can koni yellows handle and what would be the best spring rate f/r combo given that I already have pretty stiff bars
or
2. bilstain b14 PSS coilover
if I want to save some dead presidents and upgrade my stock suspension ( I have hotchkis bars f/r) on my S2 used mainly for track duty - so street comfort is not an issue would I be better served with :
1. koni shocks and some high rate springs - how much spring can koni yellows handle and what would be the best spring rate f/r combo given that I already have pretty stiff bars
or
2. bilstain b14 PSS coilover
Last edited by Nadrealista; 02-21-2017 at 10:32 AM.