Performance Tech News            from Auto-Ware
August 2010
These newsletters are intended to be current and relevant to your racing.  If there is a subject you would like to see covered drop me an email and I'll get your suggestion in a future issue. 
News - All New Data Acquisition Training

Online classes now can be tailored "on-the-fly" to match to your brand of data system.  There are literally hundreds and hundreds of slides for AiM, CDS or Pi brand data systems, so you can get click by click demonstrations of how to run your data system and understand what you see on the computer.

You will learn how to read & understand different data display types and move around in the displays.  Also, you will be able to create your own data displays and develop your own views for your needs and car.

You will gain a huge advantage in being able to create "Math Channels" and acquire data without actually putting sensors on the car.  (Wow, save time and money).

Most importantly, you will be able to read & understand general driver and car performance including: engine health, driver skills, comparing drivers, steady state handling, transient handling, chassis platform motions, and shock absorber performance & pre-failure diagnostics.
The best part is if you refer someone else who signs up, your cost is half, if you get two people to sign up, you get the sessions for FREE!
Don't wait, go to Online classes for more info.
Tech Tips -  Bleeding for Better Handling 
Depending on your rules, you might (or not) be able to use "Bleed holes" as a chassis tuning trick.

Different shock manufacturers have different opinions regarding bleed. Some address the issue with "Bleed shims" and others with bleed holes, while others may just employ what escapes past the bands/seals, all of which are driven by different thought processes and designs.

However, if your shock pistons are designed such that they can physically accommodate bleed holes (as in the photo), then you might be able to add another level of chassis tuning.

Basically, the amount of bleed impacts the "Nose" or low speed slope of your shock's damping characteristics. The result is that the timing of when the shim stack (valve) opens can be delayed with additional bleed. This means the driver may notice a change in body movement and/or transient handling (getting in or out of corners).

Just remember when drilling bleed holes to start small (0.010" - 0.015"). You can always make a hole bigger with a bigger drill, but you can't go the other way.
Equation of the Month - Center of Gravity Height

This month's equation is an oldie but goodie that may be hard to find sometimes.  So, I'll put it here for easy future reference.

CGH=(TD/2)+(((ELF+ERF-LF-RF)*WB*((WB^2-ELV^2)^0.5))/(TW*ELV)) Where CGH is the Center of Gravity Height, TD is the front Tire Diameter, ELF is the weight on the left front scale pad when the rear is elevated, ERF is the weight on the right front scale pad when the rear is elevated, LF and RF are the left and right static front weights, WB is the Wheelbase, ELV is the amount the rear wheels are elevated off the scale pads, and TW is the Total Weight of the car.
When elevating the rear wheels use a floor jack to lift the rear axle.  Do not use a bumper jack or engine hoist and lift the car by the rear bumper such that the rear axle is hanging from the car.
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John Block