TheNick

I've played with the OptimumG stuff - the user interface is much friendlier - both can get you the same answers - it is just a tad bit more work to get it out of WinGeo http://www.mitchellsoftware.com/prod01.htm

The software is a sample version of Bill Mitchell's WinGeo - you don't get the opportunity to actually model suspension from scratch but it does show you how the use the software. The excel sheets that it comes with are very useful - they are ugly as hell - but there are step by step instructions in the book. If you want 75% of the material and have a quick reference manual - pick up the Haney book instead.

http://www.amazon.com/Introduction-Race-Car-Engineering-Book/dp/0973432004 Better than any of the Smith books or the RCVD book. Shows actual application of the math and comes with suspension design software and load transfer worksheets. While you are at it check out Paul Haney's - The Racing and High Performance Tire - written by a journalist and not an engineer - very easy read - can be done in one sitting and the info is very easy to remember. My personal favorite book because it relates directly to the club racer who doesn't have the means to do all the testing in the world, or they have to work within a certain set of rules that doesn't allow mounting point relocation

There are a few other advantages that others haven't mentioned 3rd spring/damper that is only active in pitch/dive - this explains it better than I can: http://optimumg.com/OptimumGWebSite/Documents/TechTips/Springs&Dampers_Tech_Tip_3.pdf and http://optimumg.com/OptimumGWebSite/Documents/TechTips/Springs&Dampers_Tech_Tip_6.pdf You can also make your sway bar much much smaller/lighter. Also have the ability of using rising rate rocker arms. There is also the ability to change the motion ratio of the suspension very quickly if you use multiple holes in the rocker arms, this will give you a very easy change in wheel rates - you don't have to worry about taking multiple sets of springs with you to the track.

Those other EM cars were spewing crap everywhere - I guess that's pretty typical for them though right The Corvair was supercharged too The BM car was driven by a guy who's taken top 2 or 3 both of the past two years in Topeka and I think he ended up in the 35's raw time - he won PAX too - followed closely by a CM car and then myself and Geoff Chambers in a virtual tie for 3rd and 4th (he got me by .006 seconds!!!!!) I was pretty happy with how things went - that Honda leaves me with huge grins every time I drive it How come you run EM instead of XP? Too light for the 5.7liter? Our courses are significantly faster than what we saw there - last one I designed had an average speed of 45+ and I was hovering right under the rev limit at 55 for most of the course - here's an incar from an STS CRX that took 4th on PAX - no video from my car yet - we don't have the MaxQ hooked up yet with the two cameras (thats the co-driver's - I have a DL1 already in the car)

Got to see Cameron run on these today in Terre Haute - car looked very very good - put down power very well with the LS1 and Cameron seemed spot on with his patience - which was extremely important on this course. Great looking car Cam - what did you end up getting down to? I went over and started changing tires after your second run so I didn't get a chance to see the other 3.

I have a late 70's car titled as a 71. That makes me feel better about weight - I have basically the exact same setup in terms of motor - just need to get it in and running. But with autox season in full swing I don't see it happening till the fall. I made the mistake of typing in "5.0 supercharger" into Craigslist a couple weeks ago...DON'T do that You will see money disappear very very quickly from your bank account

They sell Rota wheels - Rota makes very good wheels for the price. 18racing are good people to deal with too - they were the first ones to get Rota to build a 15x7.5 Slipstream for the ST autoxers a few years ago.

Cool - I'm kinda surprised at how heavy the car is - do you still have a full interior and whatnot?

Still pretty left side heavy - any thoughts on trying to get more weight on the right rear to put power down better and deal with the chassis asymmetries that Cary spoke about above?

Talk to Marcus Meredith at Margrave Motorsports http://www.margravemotorsports.com He revalves Bilsteins on the side of his real job - I've ridden in his ESP Mustang that had 1200lb+ springs and you couldn't even feel the bumps on the course.

http://zzyzxmotorsports.com/library/roll-center-myths-and-reality.pdf Found an excerpt from the Bill Mitchell paper I was talking about Also some other good links if you are in the mood to pay for SAE papers Asymmetric Roll Centers http://www.sae.org/technical/papers/983085 Force Based Roll Centers http://www.sae.org/technical/papers/2006-01-3617 Good PDF File on FRC's and their application https://aerade.cranfield.ac.uk/bitstream/1826/2097/1/Allibert-2007.pdf

You aren't picking on me We're having a discussion And I didn't say that RC's don't matter - I just said their vertical position doesn't effect load transfer. That is actually incorrect - I went back and looked at my reference material and double checked the equations

Great thread discussing RC movement relative to CG height http://fsae.com/eve/forums/a/tpc/f/125607348/m/47110403711

Lateral load transfer is based solely on CG height and track width - the RC location doesn't have anything to do with it. If you are having issues with putting power down then you need to know what the dynamic alignment changes look like under bump. Does the outside rear toe out or in under bump? How much? Whats the anti-squat look like on these cars (I don't know but I have a feeling its a rather large percentage - but I could be wrong - its happened before ) Maybe you are running too much static camber? Try stiffer springs and run less static camber? Not as much roll so you won't need as much camber for lateral acceleration and the tire will be more upright when its time to get on the gas for exit. A large rear sway bar will also make it harder to put power down (what type of LSD? Clutch? 1.5 way - 2 way? Helical?) The LSD type will factor into what size of rear bar you need to run. In a higher HP car - I think it would be advantageous to find a way to not run a rear bar at all like 74_5.0L_Z.