HP Influenced by Stagger & Tire Pressure
Got asked by someone in another thread to post info on this;
About 50% of a race vehicles energy output is consumed by friction and dissipated as heat...
Although you might never have thought about it the Cf of a race car has a large factor involved in the tires...
Back about 30 years ago I was a top level race bike builder for Bikeways of Tucker and I built some of the most expensive bikes and wheels in the country $10,000+ for bikes and $1000-$2500 for wheelsets. Jobst Brandt was one of the foremost wheel engineers in the world for a long time and his book is one of the best on how to get max HP out of a set of spoke laced wheels. My fastest and best racers ran Italian Silk tires and they were pumped up to 125-150psi. That being said...
Tire pressure in race tires can increase RWHP up to 2HP per 1# pressure increase, why do you think they have maximum tire pressure rules for CUP races??? Surely not for safety.
At Daytona and Talladega we had a couple really goo tricks for running +5-10psi and still passing tech. Learning how to use inner liners to your inner liners to your advantage you can pick up 1/2 second a lap in Qualifying.
Tire Stagger is the same deal, the more you run the more drag you put on the car up the straight. The key is to get maximum turn in the corner with less stagger as it is as much as +/-10HP per inch... on both pavement and dirt.
As to how you test it on the chassis dyno you just get an air gauge and raise the air pressure in both rear tires as to not change stagger.
As for stagger you just change the LR smaller or RR bigger and do it an inch at a time and see what happens.
I have done this testing at least 50 times for teams and customers over the past 25 years and most folks don't believe the results til they try it at the track and see the results.
Another post that relates to this is the one on the use of locking diffs on dirt. If you know what you are doing there is 25RWHP in this system.
Your chassis dyno needs to be run in uncorrected mode, with no curve smoothing and has to be accurate to less than 1% to produce credible numbers. This eliminates about 99% of the chassis dynos out there but you will still see some changes hopefully.
A lot of folks don't see the stuff I do because the repeatability and accuracy of their instrumentation, software and inertia wheel is not capable of showing A/B/A repeatability to less than 1%.