different extreme alignment.
not quite conventional wisdom.
After getting back from Laguna. I had just put on an NB front Subframe and V8 roadsters Arms the week before the event. I was out of time and had the car aligned at a local Less Schwab. I went for conventional wisdom and asked for 3 degree front camber and 2.5 in the rear. One of the front camber bolts moved day 1 steering wheel went crooked and it became toed out. I moved it back with the aid of Kieth's Flyin Miata hub stands set it back to where the toe was right and camber was the same on both sides withot touching the tie rods. steering wheel was centered again. Kieths gage was reading a little over 4 degrees though. I assumed It wasnt really that much and the toe zeroed out perfectly as soon as I had the camber on both sides the same. Now Im cheacking it again with my home gages and Im still getting just over 4 degrees in the front but when I check the back its only 1.5 degrees. Here is the thing. The car was awsome. super well balanced and responsive and put down 350 hp amazingly well without getting twitchy at all. It was a rocket coming off corners. Front tires seemed to wear a little more on the inside edge but the rears wore even. I was running about 2.4 seconds under my previous best times. This may have me re-thinking conventional wisdome if what Im measuring is right. 4.0 degrees camber front. 1.5 rear for high hp car. |
Interesting, I wonder why guys with temp guages dont find this info out easily?
maybe you were just on the ball that day? Dann |
Originally Posted by nitrodann
(Post 1009363)
Interesting, I wonder why guys with temp guages dont find this info out easily?
maybe you were just on the ball that day? Dann I run a spec miata as well, compleatly different animal. It is never straight line traction limited. |
Interesting on the rear camber.
What rear camber were you running before? 2.5* were you having traction problems out of corners with that set up under the same weather/track/tires? What shocks/bars are you running? |
I run less rear camber in Theseus than I do in Rover, but not that much less. Rover gets ~2.8-3.0 rear camber, Theseus gets 2.5* and 1/8" toe in.
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1 Attachment(s)
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Bob -
A) Congrats on the badass time at Laguna Seca B) Did you take any probe pyrometer readings at all? Is that something you would normally use for alignment setup? |
I did not take pyrometer data.
My personal experiance Is I never saw laptime gains going much past 2 in the rear. I never reached any limit of gains in the front however as I always ran it max the adjusters would allow which was something like 2.8 to 3. I knew I wanted to be able to quickly adjust rear camber because of running ProSolo in SSM. In ProSolo about half the difference you can make in your run occurs in the first 60 feet under full straight line traction limitations. The fast cars in that class run very little rear camber. 2.5 results in about half of a 275/35/15 working real well in a straight line acceleration. You usually never get out of second gear if you can get the gearing tall enough for the full run and my car is straight line traction limited between ~4000 -7000 rpm in second even with 275 A6 Hoosiers. The spec miata is a completely different story it seems to like more camber period. That car is never straight line traction limited however. |
Originally Posted by GeneSplicer
(Post 1009414)
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One thing I dont undrstand is why what I am measuring is so different than the printout from Les Schwab 1 degree less in the rear and 1 degree more in the front. Im pretty sure the rear did not move.
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Did you know those guys? Did they use calibrated laser equipment? Is their lift 100% flat and calibrated?
Still an equal 1* increase front and 1* decrease rear doesnt sound like measurement/calibration error. What does the printout read? |
Originally Posted by Spookyfish
(Post 1009381)
Interesting on the rear camber.
What rear camber were you running before? 2.5* were you having traction problems out of corners with that set up under the same weather/track/tires? What shocks/bars are you running? |
Originally Posted by Spookyfish
(Post 1009487)
Did you know those guys? Did they use calibrated laser equipment? Is their lift 100% flat and calibrated?
Still an equal 1* increase front and 1* decrease rear doesnt sound like measurement/calibration error. What does the printout read? |
Originally Posted by GeneSplicer
(Post 1009414)
Front Camber -5 to -7 Rear camber -1 to -2 Caster 9 to 15. |
Originally Posted by bbundy
(Post 1009573)
looking up V8 supercar setups on line. typical
Front Camber -5 to -7 Rear camber -1 to -2 Caster 9 to 15. Lowering the rear camber makes sense since it should increase the tires contact patch. 99% of people don't have 350whp, so they never needed to try it. |
Originally Posted by bbundy
(Post 1009362)
4.0 degrees camber front. 1.5 rear for high hp car.
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Originally Posted by bbundy
(Post 1009501)
Running 949 XIDA double adjustable shocks. 900/500 lb springs. ISC racing sway bars. 1-1/4" 1/4" wall front. 5/8" rear. Swaybars are a bit softer than they might seem because the arm lengths are longer than other bars. OS-Giken rear diff with slightly different internals than the standard miata setup for softer progression of lockup under high torque. Its 949's High horse power version. I tried 3 different setups with the diff before liking the feel of this one the best. unfortunatly measurments on the diff tune were seat of the pants as well.
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fyi - v8 supercars were live rear axle (solid diff) until this year when the Car of the future was rolled out. So not entirely independant suspension....I would think most info would be historical, pre this year at this point.
Crusher has been running 3.5 ~ 4.0 front for a while. Yup, less rear camber for high power cars. |
Originally Posted by Savington
(Post 1009672)
I bet a large part of it has to do with too much front spring and way too much sway bar overall. With that much rear sway, you need to stand the tire up straight to get it to hook up.
I also measured camber again after just rolling the car in. It is not so extreme now. More like 3.75/2.25. when I was measuring it before I had the fronts on FM hub stands and the rears not. I don’t think the rear suspension was not settled when I was measuring because I lifted thecar to get the hub stands on the front. I think I’m finding I need the hub stands for all four corners to do anything accurately. |
Originally Posted by emilio700
(Post 1009660)
Crusher has been running 3.5 ~ 4.0 front for a while. Yup, less rear camber for high power cars.
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Originally Posted by bbundy
(Post 1009706)
How did you get that much with stock arms. did you make some modifications to something?
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Originally Posted by emilio700
(Post 1009860)
Prototype offset Delrin bushings. The production pieces will be a much lower cost acetal with better lubricity than Delrin. Maybe 8 weeks out for the first batch.
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Originally Posted by mx5-kiwi
(Post 1009680)
what power level constitutes a high power car where less camber starts becoming a setup factor?
Up to you to determine what camber your particular set up, power and conditions want. Get a pyrometer, consistent driver and lap timer. Report back ;) |
Originally Posted by emilio700
(Post 1009860)
Prototype offset Delrin bushings. The production pieces will be a much lower cost acetal with better lubricity than Delrin. Maybe 8 weeks out for the first batch.
I was cussing at how much friction there was in the urethane bushings in the V8 roadster arms when I was installing them. I was hoping they would be much better than they are. Then I figured out most of the joints pivoted better if I greased every surface and they slid inside the arms instead of around the center pins. This got the friction down to just a few pounds. No telling how long it will last or until the mix of antiseize and redline grease I used turns to dirt though and everything will need to be taken apart again to get grease in effective places. Id like to find real bushings that fit the V8 roadster arms instead of the stupid material choice urethane ones they came with. |
Originally Posted by emilio700
(Post 1009860)
Prototype offset Delrin bushings. The production pieces will be a much lower cost acetal with better lubricity than Delrin. Maybe 8 weeks out for the first batch.
Bob, your V8R arms have poly? I swear the only set of them that I've seen had delrin, and the owner of the car claims that every bushing in the car is delrin, even the steering rack. |
Originally Posted by Leafy
(Post 1010129)
I'm confused, Delrin is just Dupont's TM name for Acetal. And better lubricity, I'm guessing you're going to PTFE impregnated Acetal. If that ends up being too soft we picked up some glass reinforced PTFE Acetal in the shop that is the tits..
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Of course. And it make sense to go non-branded, they price of plastics seems to vary wildly based on distributor even when you know the stuff is coming out of the same batch from the same plant.
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Originally Posted by Leafy
(Post 1010129)
Bob, your V8R arms have poly? I swear the only set of them that I've seen had delrin, and the owner of the car claims that every bushing in the car is delrin, even the steering rack. In My opinion if a person wants stiffer A-arm bushings they should go straight to Delrin or acetal or whatever. The car rides better on A-arms that pivot more freely allowing the shocks and springs to do there job much more so than having just a miniscule amount more if radial vibration damping over real bushings. Poly is good for locations that don’t need low amounts of sliding friction like engine mounts, diff mounts etc not for bushing where low sliding friction is what is really needed. |
I never hear anyone talk about UHMW as a viable bushing material. UHMW is dirt cheap and has a friction coefficient close to Teflon.
Does it have some quality that makes it unsuitable as an A-arm Bushing? |
Originally Posted by crowder92
(Post 1010417)
I never hear anyone talk about UHMW as a viable bushing material. UHMW is dirt cheap and has a friction coefficient close to Teflon.
Does it have some quality that makes it unsuitable as an A-arm Bushing? |
Originally Posted by emilio700
(Post 1009860)
Prototype offset Delrin bushings. The production pieces will be a much lower cost acetal with better lubricity than Delrin. Maybe 8 weeks out for the first batch.
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I would think that large amounts of front camber would create a sub-optimal situation for braking, much like accelerating does for the rear in a high-horse car. Is the difference made up by braking less and cornering faster? Or is cornering that much more important to laptimes than optimal braking?
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Originally Posted by sixshooter
(Post 1010717)
I would think that large amounts of front camber would create a sub-optimal situation for braking, much like accelerating does for the rear in a high-horse car. Is the difference made up by braking less and cornering faster? Or is cornering that much more important to laptimes than optimal braking?
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Plus, you load the front tires so much with the weight transfer under braking. You're never going to load the rear tires anywhere near as much with acceleration out of a turn, so acceleration grip is much more camber sensitive than braking grip.
-Ryan |
E, what temp spread do you get across the tire @ 3.5-4 degrees camber?
I had Creampuff set at 3.6 for a few events last year, the pyrometer and my SOTP feel did not agree with each other entirely... |
Originally Posted by Blackbird
(Post 1010852)
E, what temp spread do you get across the tire @ 3.5-4 degrees camber?
I had Creampuff set at 3.6 for a few events last year, the pyrometer and my SOTP feel did not agree with each other entirely... |
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