bbundy

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.

nitrodann

Interesting, I wonder why guys with temp guages dont find this info out easily?

maybe you were just on the ball that day?

Dann

bbundy

I don't think many have gone to 4 degrees in the front because you cant get there without aftermarket or modified A-arms. I think the low amount of camber in the rear works because of the horsepower. It's like a muscle car alignment.

I run a spec miata as well, compleatly different animal. It is never straight line traction limited.

Laur3ns

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?

Savington

iTrader: (31)

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.

GeneSplicer

iTrader: (14)

Reminds me of V8SC...

Scrappy Jack

iTrader: (2)

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?

bbundy

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.

bbundy

Yea and unlike Nascar, V8 super cars run adjustable independent suspension both front and rear. They chose those settings for a reason.

bbundy

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.

Laur3ns

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?

bbundy

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.

bbundy

I normally get my car aligned at a race shop and corner balance it. I was out of time and just had it done at a local tire shop. They had the good hunter laser equipment. Guy seemed competent. I do not know about how well calibrated it was. I am checking it with DIY equipment so I might be skeptical of my ability to measure it accurately myself.

bbundy

looking up V8 supercar setups on line. typical

Front Camber -5 to -7
Rear camber -1 to -2
Caster 9 to 15.

Ian

iTrader: (2)

Wow, that's more than I expected on those v8 supercars. Looks like you can never get enough front camber.

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.

emilio700

iTrader: (3)

Crusher has been running 3.5 ~ 4.0 front for a while. Yup, less rear camber for high power cars.

Savington

iTrader: (31)

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.

mx5-kiwi

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.

Two questions - Can you achieve that higher camber on stock NB arms? and what power level constitutes a high power car where less camber starts becoming a setup factor?

bbundy

You know I think I was wrong on the spring rates I think 800/500. Whatever Emillio talked me into. With the amount of rubbing I get all over the inner fenders I couldn’t imagine going softer would be better. I use all the bump travel now both front and rear and the plastic protectors between the top of the shock and the bump stop are smashed. Also the arm lengths on the sway bars are 11” in the front and 7” where I have them adjusted, Most other bars are 9” and 5”. The front bar is effectively not as stiff as the big racing beat bar and the rear is similar to a mazdaspeed bar. My car is also heavy compared to a gutted track car ~2180 without much fuel and no driver.

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.

bbundy

How did you get that much with stock arms. did you make some modifications to something?