Weather Correction for Supercharged Engines

I have added a new Chapter 15 to my MSA Weather Corrections Book (www.DragRacingPro.com/Books.html) to specifically cover supercharged engines – methanol, gasoline and nitromethane. If you previously purchased this book directly from me (or from one of our distributors) please send your email address to request your free copy of the new Chapter 15 in the PDF format (PHale@DragRacingPro.com).

Weather correction for supercharged engines does not follow the methods used for naturally aspirated engines. The large cooling effect from the evaporation of the fuel upstream of the supercharger reduces the impact of the ambient temperature changes significantly. In order to determine the pounds of air in each “gulp” of the blower, you need to know the density of the volume of air trapped between the rotors and the case. And the density of this blower inlet air is definitely not the same as the ambient air density you measure back in the pits or staging lanes.

Chapter 15 – Table of Contents
 Swamp Coolers
 Supercharged Engine Fuel Properties
 Fuel Saturated Air Density Index (ADI)
 Methanol Saturated ADI for Dry Air
 Methanol Saturated ADI for Dry Air with Fuel Temperature Effect
 Methanol Saturated ADI for Moist Air
 Methanol Saturated ADI vs. Traditional ADI Examples
 Gasoline Saturated ADI
 100% Nitromethane Saturated ADI
 90% Nitromethane Saturated ADI
 Universal FuelSat ADI Equation

Patrick Hale
www.DragRacingPro.com
602.992.2586

 

I’ve had several requests for copies of Chapter 15 from people who have not yet purchased the MSA Weather Book . . . but are considering buying it and would like to have a look at Chapter 15 first.

So . . . in this time of digital media, email and the internet . . . I have decided why not! If anyone on ITA would like a FREE copy in PDF format . . . send your email address to PHale@DragRacingPro.com.

Patrick Hale
www.DragRacingPro.com
602.992.2586

 

The price of knowledge is a small fraction of the cost of ignorance, buy the book.

 

Great book Mr. Hale,
For me, it's already becoming a very precious "cost saving tool".
Thanks,
Charles Stewart

 

Thanks Chuck, Mike and Charles for the comments!

"Motorsports Standard Atmosphere and Weather Correction Methods" is a 104 page book about weather correction and analysis for all forms of Motorsports! It contains all the equations, all the graphs, all the technical background and practical advice you need to get the most out of any weather station! This book is the result of my 35+ years of research to develop computer software for Motorsports . . . and is the most comprehensive technical book on weather correction ever published. Everyone will learn something new from reading this book. The total cost is $55, which includes free USPS Priority Mail delivery to any address in the USA!

The "MSA Weather Book" would make a great Holiday gift for every racer and tuner!

Patrick Hale
www.DragRacingPro.com

 

Since I first got into publishing drag racing math for Hot Rod Magazine (1986) the most frequent question I get asked is “how much more HP do I need to run XYZ seconds quicker.”

I just came up with a simple (I hope) way for all of you to do this calculation for yourself. It does require the cube exponent (i.e. ^3), that is, multiplying a number by itself 3 times. For example, the cube of 2 is 8 = 2 x 2 x 2.

For most drag racers, the question is always “how much more HP per 0.01 seconds”. The ET equation is:

HPadd = HP x ((ET / (ET – 0.01))^3 – 1)

Or “how much more HP per 1.0 MPH” and the MPH equation is:

HPadd = HP x (((MPH + 1.0) / MPH)^3 – 1)

For a specific math example, let’s use a supercharged TAD, a class I have some experience with. The engine makes about 3700 HP and a great run would be 5.25 seconds @ 273 MPH.

TAD ET: HPadd = 3700 x ((5.25 / (5.25 – 0.01))^3 – 1) = 21.2 HP
TAD MPH: HPadd = 3700 x (((273 + 1.0) / 273)^3 – 1) = 40.8 HP

So for TAD, with everything else about the racecar, weather and track conditions being the same . . . it takes 21.2 HP more to pick up just 0.01 seconds. And a whopping 40.8 HP more to go 1.0 MPH faster on the racetrack!

You can clearly see that the ET and MPH HPadd answers are different for every class, and are based solely on the current levels of HP, ET and MPH. These two equations should work well for any drag racing class, from the slowest Stock racer to Top Fuel.

The derivation of these two HPadd equations and all kinds of other Motorsports math are all included in the “MSA Weather Book”.

Patrick Hale
www.DragRacingPro.com

 

Based on lots of feedback, I have decided to breakout the JetArea App from the Nitro Tuner software into a stand-alone fuel system and weather tuning program. A free demo version of JetArea is also available – just send me an email to request a copy.

All the details about purchasing JetArea can be found at http://www.dragracingpro.com/Software.php

Patrick Hale
PHale@DragRacingPro.com

 

Attn: Top Dragster and Top Sportsman drag racers

I have now added ET prediction to the JetArea computer. The new ETProRx app is a simple, yet very powerful ET prediction program designed to work seamlessly with JetArea. You use JetArea to determine the main jet needed for the changing weather conditions and ETProRx to predict the dragstrip ET (or dial-in) for the next run.

A free demo is available and details about JetArea can be found at http://www.dragracingpro.com/Software.php

Patrick Hale
PHale@DragRacingPro.com

 

Based on feedback from racers using the JetArea computer, I have decided to stop bundling the software with the tablet PC. You can now purchase the JetArea software on CD and install it on your own tablet, laptop or desktop PC.

A free demo is available and the details about JetArea can be found at http://www.dragracingpro.com/Software.php

Patrick Hale
PHale@DragRacingPro.com

 

Based on feedback from many racers over the past several years we have completely remade the Nitro Tuner software. This brand new program is called NTProRx (Nitro Tuner Pro Prescription) and is completely focused on “simply” duplicating your Baseline “best HP” engine tune-up as the weather conditions change during the day, from day-to-day and from track-to-track.

NTProRx is semi-custom software targeted at NHRA TF and FC nitro tuners as well as Nostalgia TF and FC (or any other roots blown nitro engine application). A version named TAProRx is designed specifically for NHRA Top Alcohol tuners who use PSI screw supercharged methanol engines.

Free demos of both versions are available – just send me an email to request a copy. More details about the new NTProRx and TAProRx software can also be found at the bottom of http://www.dragracingpro.com/Software.php

Patrick Hale
PHale@DragRacingPro.com

 

Patrick Hales series of books and info have been one of the most important tools you could ever have in your possession.
Understanding the weather aspects of tuning an engine is something that you may "pick up" over your career. This book answers it all!!

I laugh at how many people use Grains of Water as a tuning aid, but have no idea what a grain of water is, what unit its measured in, and how many Grains of water can exist in a unit of air.

I've read an used this book hundreds of times, and I carry it with me at every race.

Knowledge is Power.......buy this book!!!!