Was wanting to know if anyone has encountered not being able to get enough rear camber OUT of the car. I've got the rear aft adjusters all the way in and I'm still at (-1.2 deg). At this setting I'm still getting a 10 degree rise in temp on the inboard tread section telling me I need even less static camber.

Conditions: 8 hard runs on good asphalt. Rear tire pressure 42 psi on 245 710s. Zero toe. Final temps - 110 outboard/midsection, 120 inboard. Ambient temp in the high 50s.

Both sides are equal from an adjustment standpoint and also on the temp readings.

 

I'm surprised you are limited to 1.2 degrees in the rear, most cars can get more.

That said, I wouldn't be too concerned about a 10 degree gradient, in fact it's pretty common to see slightly higher inboard temps on a properly set up car since the inside heats up more under braking and straight line acceleration due to the static camber.

If you can't get any more camber, you might try dropping the pressures a pound or so, I would tend to think that they may be a bit overinflated. It is also worth noting that 120 degrees is still very cold.

Steven

 

I knew this would be hard for me to explain. I don't need more camber. I'm looking for less (i.e. -1.1 deg). Agree 120 is not very hot but that's all we could get on the asphalt where I was running in Nashville. The place is very easy on tires. Wasn't like we weren't trying though.

As far as lower pressures go, at anything below 40psi I can feel what I think is the contact patch bind and release coming out of corners. Kinda weird like it's twisting due to sidewall compliance.

Thanks for the feedback.

 

WOW I have almost -2 in the rear, would take more if I could get it... Ran -2.5 on my Corvette and it would put power down hard enough to pull a front wheel up out of a turn.

 

Sorry, my fault you want "more camber" which I always hear as "more negative camber". If I had thought a minute longer... yeah you're wanting a cooler inside and want to stand the tire up more. My misunderstanding, a little slow tonight.

I do still think 10 degrees on the inside is nothing to fret about.

Good luck,
Steven

p.s. I also run -2.0 in the rear as a baseline, a little less up front, and generally am happy with a 10 to 20 degree spread across the rear, as long as the inside is the hot end and it's a smooth gradient.

 

I've heard you mention that before, and I know your success with it. I'm just relating what the pyrometer is telling me. The Corvette doesn't have the same dynamic camber curve of the RX-8 so that's probably not a valid comparison.

Overall, the car is definitely loose with the camber down that far, but still very drivable. Primary problem is putting power down out of corners as I'm sure you know, but a bigger front bar would help that if I can lose just a little more camber.

 

Now I got it.... You are not checking the temp the right way. Checking them after a run will always get you bad numbers, because you turn left and right and have wheel spin. The only way to get real numbers on what the tires are doing is a skidpad. Run a few laps in one direction around the pad and check the outside tires, the ones doing the work. Then go the other direction and check the other side. After you have done that you will be able to better decide if your alingment is ok.

 

Thanks, will do.

 

Yeah the vette gets even more.

The reason you cant put power down is because you need more -camber. You are standing the tire on the outside edge and have no contact on exit. Go ahead and stand that tire up strait... Then sell the RX8 and by an Fbody, might as well own a car with no adjustment if you are not going to use it. You can also run a bit of toe-in on the rear if you are loose.

 

And here I was thinking that the purpose of adjusters was to allow for trying different settings. Thanks for clearing that up.

Anyway. My original question was if anyone has tried (unsuccessfully) to get less than (-1.2 deg) camber in the rear. Also, I've had the camber out to -1.7 before and didn't notice a significant difference in the temp gradient. I suspect from this that the car has adequate dynamic camber (in the rear anyway) and the adjusters are more for fine tuning. This would also explain why the large variance in setups have proven to be roughly equal so far.

I'm not conviced on the cause of the exit wheelspin. With the RB swaybar it put the power down great. Just wouldn't turn worth a darn. You guys were right on about that.

Appreciate the feedback. Expect I will try many more setups before I'm done.

 

when I took mine in to have a performance alignment done, the rear camber was at -1.0. So I am sure you can get more upright thatn -1.2. but as mentioned, I am not sure why you would want to. Good luck.

 

I think I know what the difference is. My car sits about 1/2 inch lower in the rear since I put the konis on. That would explain the camber increase. I seam to remember getting -1.0 a couple of years ago when I was doing the original baseline on it, just can't find my notes.

 

IMO you shouldn't increase it

every car is different, what somebody did on a Vette has absolutely no correlation to what you do on an RX-8

fuel level and driver weight have a big influence on the rear camber reading, the more weight of either the more negative a particular rear camber setting will read on the alignment machine

 

Hey, I know the answer on this one! If you are at the limit but want less you have two options, one is to decrease the neg camber by some means, I've seen it done by using washers on upper A arms. Your other, more simple option is to add a little toe out to compensate for the neg camber, this will make a big difference. When you are running a degree or more of neg camber with zero toe, that means that since a leaned tire tracks into the same direction that it is leaning, your effectively have a pretty strong toe-in. This leads to binding and scrubbing, and poor launching. A little toe out gets the tires tracking back in the same direction that the car is rolling and makes everying work better.

 

that's a pretty broad general statement, you ran a suspension analysis specifically on the RX-8 to determine that? I already know the answer because my own testing doesn't back that up ...

 

I just don't understand why you would want less.

 

So you did extensive testing to reach that conclusion?

C'mon man, you only just got some wheels and tires, and frankly those tires don't compare to what we run on ...

 

Here's something I found a year or two ago, I printed it out & keep it in my reference binder that I take to all events. Disclaimer, it's handy but it's not the gospel.
http://www.wtrscca.org/tech.htm

This year I took the Evolution Dial-In school taught by Andy Hollis. I had the same situation, rear insides were hot (ran on skidpad and a helper took temps immediately after running several laps).

One of the many things I learned in this class is to consider the multitudes of factors affecting car handling. For tire performance, the slip angle is affected by the stiffness of the sidewalls and/or compound (stiffer=smaller slip angles) - TeamRX8's comment above reminded me of this. There are a dozen or more suspension settings that can affect performance as well. Also, there is your own driving style....

I got closer to even temp. settings by raising rear pressures. However, this is not necessarily going to solve all your problems since each course on each day presents you with a different set of variables. What I'm trying to do is just find my happy medium, and drive consistently well within that.

 

Because the car is faster at the lower rear camber settings for me. I don't really know if even less camber would be good, but I can't tell for certain unless I test it. Finding the best compromise for stock class setup doesn't always follow common sense rules for a rully prepped race car due to the constraints imposed by the rules. Best thing is to try as many setups as possible to see what's best for you and where you run. It's not unusual for the fast cars develop in one direction for a couple of years and them go a different direction when someone discovers something new. A good way to end up behind is to emulate what other people used to do.

Meanwhile, I'm kinda stalled out right now because a certain FSB is way behind schedule.

 

I can think of a few reasons to run less rear -camber.

1. You have not figured out the setup to get max work out of the front of the car, so you have to give up rear traction by removing -camber.

2. The driver carries to much speed on corner entry, does not slow down enough, so your car pushes. To make up for the driver not slowing down you have to make the car artificially loose so it will rotate.

3. You are setting up your car to drag race rather than to carry corner speed.

4. You have more -camber than the tire manufactures suggest running with their tires.

I think in most cases #2 is the reason.

 

I got the impression that GH didn't think so, maybe you can give him some driving lessons sometime

there's more than one way to skin a cat, the question is which one has the least negative consequences for the best performance

I've run your setup Jason and had the same consequences that you've mentioned here time and again

I'm not aware that you've run my setup, given that I've yet to fully divulge it here

I fully admit to being a hack driver, I don't think you can say the same for GH, so you don't simply have to take my word for it

just because I'm not fluent as a driver doesn't mean I can't set the car up, you like to brag about being a champion yet you still can't own up to the fact that you weren't the fastest car/driver on either day with both courses being very corner speed intensive, congrats on your win though

 

Here we go again...

 

i'm staying out of this one....

 

Good old mAs shows up again... My codriver can beat you and I have to live through him because I all I can do is talk trash on the web. I doubt that you have run MY setup, you may have had some parts of it. I am sorry mark because I was not fastest either day, just overall, do you somehow feel cheated? I could see how if you were even in the group at all during the year you could think as much of yourself as you do.... For the record ask anyone that knows me, I talked just as much trash before I won as I do now.

 

and i thought talking trash was one of the main requirements for this section of the forum...