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I took this photo last night, when I pulled my track wheels down from the rack to get ready for 4 days at Hallett next week. The blue ring around the outside edge is from overheating caused by over-driving and rolling the tire. This is what I'm hoping that 3.5* of negative camber will help solve. Obviously, I have some work to do on the nut behind the wheel, too.
nothing looks out of order visually, I guess I could measure and see if driver side LCA is in any way different than passenger side or perhaps sub-frame mounting points shifted?
The subframe can’t really shift that much. It’s hard to know that without having ever removed it though. If you lived nearby I’m sure I could get it there for you. Otherwise it’s a bit hard to explain the full procedure on how to go through and make sure everything is positioned to provide maximum camber. The factory and average mechanic can’t be bothered with it. All they care about is whether it falls within the factory alignment range in the service manual.
Well it’s not that simple. On one hand it may be overheating there as stated. On the other, the more camber there is the more the inside tread is used and the less the outside tire corner is used when not cornering hard. So when you’re on the cool down lap, pits, etc. the outer tire corner is just sitting out there without pavement contact, not getting dirt on it like the inside, and so on. That contributes to the noted appearance too.
Sorry to be persistent, but I still believe the (imo) too low rear spring rate that was proposed elsewhere is contributing to a lot of roll and over-compression of the rear shock/suspension. This condition also results in the chassis pitching over the slightest bumps and ripples because of the front vs rear spring frequencies being too far out of synch with each other.
Otherwise don’t discredit yourself too much. You are by all rights a pretty decent driver. That said, we’re all ripe for improvement.
Originally Posted by Steve Dallas
I took this photo last night, when I pulled my track wheels down from the rack to get ready for 4 days at Hallett next week. The blue ring around the outside edge is from overheating caused by over-driving and rolling the tire. This is what I'm hoping that 3.5* of negative camber will help solve. Obviously, I have some work to do on the nut behind the wheel, too.
Ryan was sure about having to machine them to fit 2009 cars, as his personal car is a 2009. He said they noticed the different diameter, when they removed my spindle, then measured it, and realized it would press right in, without modification. He said mine is the first car they have done without modification of the part, but he has never had a 2010 or 2011 in his shop before.
In any case, the information is out there now. Those bushings can and have been made to work in all model year RX-8s.
Ok, pulled the S1 bushings out last night (they popped out with a few hammer whacks) and it will take quite a bit of machining to make them work on the earlier models
Ball joint stud hole has to be resized with a 2” per foot taper ball joint ream and both the body and flange diameters have to be machined smaller in a lathe. The amount of material left between the modified stud hole and body OD is going to be very, very thin. It will take a sharp tool and proper technique to avoid tearing through.
I wish I had saved some better photos of this, but here is a new tire (RE71R) taken off the right front of my car after one track day. You can see considerable outside wear. After two more track days, the outside edge was corded on two of them. (Yes, I rotate my tires between track days.) My newfound camber should solve that.
Verdict is in. Camber solves all ills. OK. That might be an exaggeration. The shorthand version is, the car had a lot of grip and exhibited no bad behaviors. It was driven by several club racers and other instructors, and they all complimented its handling. I also set a new personal best lap time, which is somewhat amazing, considering my old PB was on new RE71R tires, and I had an old set of RC-1s that I was trying to trash on it this time. Actually I repeatedly trounced my old PB. The cool weather Sunday morning probably contributed, but that was probably counteracted by the fact that I could only get 87 octane gas.
Ok, pulled the S1 bushings out last night (they popped out with a few hammer whacks) and it will take quite a bit of machining to make them work on the earlier models
Ball joint stud hole has to be resized with a 2” per foot taper ball joint ream and both the body and flange diameters have to be machined smaller in a lathe. The amount of material left between the modified stud hole and body OD is going to be very, very thin. It will take a sharp tool and proper technique to avoid tearing through.
I am not familiar with any other design changes in the 2010-2011 spindles. Is there any reason not to just buy a set of 2011 spindles to replace yours?
Maybe the word "unexpectedly" is too strong. There is a huge difference between feeling fine, then snapping into a spin, which is what it was doing before, and feeling fine, then beginning to step out in a save-able fashion. The lateral load threshold has also moved considerably. Before, it would hold 1.2G and snap by 1.3G. Now, it holds 1.4G and starts to come around at 1.5G.
The car is no longer twitchy; the driver can feel and correct the oversteer.
Maybe the word "unexpectedly" is too strong. There is a huge difference between feeling fine, then snapping into a spin, which is what it was doing before, and feeling fine, then beginning to step out in a save-able fashion. The lateral load threshold has also moved considerably. Before, it would hold 1.2G and snap by 1.3G. Now, it holds 1.4G and starts to come around at 1.5G.
The car is no longer twitchy; the driver can feel and correct the oversteer.
Just curious whether pyranometer data backs your lap times and gees. Would be nice to know your tire temps and see how similar they are to the recommended 10-15F warmer inside temps.
I'm 10k front 7k rear, oem front sway disconnected rear sway, 13.5" all around, -2.7 front -2.3 rear camber. I wonder if I would also benefit from more camber. My tire wear is fairly even, tire temps are a little warmer on the inside. Running 235 width 100TW tires on 17x9. I'm maxing out at around 1.3g on these tires at the limit.
Just curious whether pyranometer data backs your lap times and gees. Would be nice to know your tire temps and see how similar they are to the recommended 10-15F warmer inside temps.
I'm 10k front 7k rear, oem front sway disconnected rear sway, 13.5" all around, -2.7 front -2.3 rear camber. I wonder if I would also benefit from more camber. My tire wear is fairly even, tire temps are a little warmer on the inside. Running 235 width 100TW tires on 17x9. I'm maxing out at around 1.3g on these tires at the limit.
Ps, did you perceive or measure a meaningful reduction in braking traction?
We did not have time to employ the pyrometer. Part of the certification process is to wear the candidates down, so there was no time for anything other than driving, role playing, and testing. It was 12 hours per day of nonstop punishment for the 1st 3 days (except for some sporadic classroom time and a short lunch break). Day 4 was more relaxed, as those of us who passed just had real students, but by day 4, I was mentally and physically exhausted and just playing defense. I had already won the weekend, but could still lose it by fumbling the kneel-down, so I didn't drive more than 2 sessions. No mistakes. Even driving those required parking in the paddock and jumping into students' cars, so there wasn't any time to take measurements in the hot pit or anything like that. The very even tire wear I saw tells me I am pretty close, though.
My setup is 8K / 5K springs, Progress MX-5 front bar, OE rear bar, 13.5" square with full tank and driver, -3.5 front and -3.0 rear camber, 255 tires on 17x9 rims. Pending further testing on my home track, I am very happy with where the car is right now. Yes, I need more spring, but this is a dual purpose car, so I'm keeping it compliant on purpose, although I'm tempted to bump up to 9K / 6K for a little more rear spring relative to the front. I can do that without having the shocks re-valved. Next set of tires will be 235s or 245s now that I have learned the benefit of a light "stretch".
As for lost braking performance, I can't say yet. The last time I was at Hallett, I did not have the AIM Solo data logger I am using now and was using my phone with a SkyPro GPS and Harry's, so I can't compare data on a like-for-like basis. I was also on stickier tires. It seems like I have to brake a little sooner now, but I am also carrying more speed and running harder tires. My lap times are better on those harder tires, so something shifted in the right direction.
When I put a bunch of camber in my Miata, I did not really notice much difference in the braking zones at my home track. The tires compress some under braking, which widens the contact patch, so I don't think there is much of a penalty. Anyway, I am perfectly happy to give up a little braking time to exit the corners faster and carry the extra speed all the way down the straight.
Another anecdotal "data point" is my friend Terry's (owner of Vorshlag Motorsports) formula for track performance: widest tires you can stuff and as much camber as you can manage--up to over 4*. He holds some track records and is pretty successful in club racing and AutoX, so he can't be totally wrong.
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Last edited by Steve Dallas; 10-19-2017 at 08:30 AM.
Does anyone have alignment specs for a car that's had considerable weight reduction and increased power. Just trying to get an idea of whether on not most of these specs will be in the ballpark of what I'm looking for on my car.
So this is really screwed up. I had someone measure a new 2006 NC MX5 LCA ball joint stud and it also has a 10 degree taper the same as my S1. Now I’m wondering if whoever makes the bushings also makes them for other models and got the wrong ones in the package I bought from Mazda Motorsports. I’ll be calling them on Monday to figure this out. Vorshlag decided they couldn’t machine the bushings I have afterall. If I can get bushings with the correct ball joint stud hole then I’ll just buy a pair of 2010+ uprights.
That's annoying -- I was somewhat hoping to be able to use S2 LCAs on an S1 as a potential suspension tuning option. (I heard that the S2 LCAs have a longer ball joint to lower the roll center).
I don't think there is any benefit to lowering the roll center with my current setup, however, so I guess it isn't really a loss.
well it turns out that they were asked by MM to duplicate a part for the NC Cup cars and they just duplicated it. Apparently everybody just bolted them on and never noticed that the taper is incorrect. Since that series is dead now that the ND is out the bushings will likely never be made again.
The problem with using them in the S1 spindles is there isn't enough meat on the head end of the bushing to keep it chucked up in the lathe while machining the main body diameter down. There are ways around it, but that's going to be time/money/hassle. So the logical conclusion is to either use S2 spindles starting with Part No. F189 or *maybe* use NC spindles. I think the NC spindles are lighter and possibly weaker, but everything bolts up otherwise. They cost about $100 less each new from Motorsports, but used are about the same cost. Class rules require me to use RX8 parts only.
Well the 2009+ NC received updated uprights that changed the wheel/control arm relationship to lower the front roll center. I suspect the S2 RX8 uprights starting with F189 part number may have gotten a similar change.
10-06-2017, 09:15 AM
so obviously some room for adjustment
