Turbo Sizing Worksheet

[Bow]

Ever wondered what size turbo you need for a target horsepower?

First off, if you have any interest in Turboing your car, go get Corky Bell's book, Maximum Boost (ISBN: 0837601606)
http://www.bentleypublishers.com/images/covers/cv_gtur.jpg;jsessionid=aY06LPSKdzE9

It is a wealth of information on turboing an engine.

Besides that, the guy lives in San Antonio...

Any way, I actually looked into turboing my KA24DE a couple years back, but decided not to.

I have this book and read it, then took the formulas and put them into EXCEL.

This will give you the amount of CFM you need for a Target Horsepower.

Here is the catch: you will have to know how to read Compressor maps in order to find the turbo and trim you will need.

Check it out, if you are so inclined and questions and/or comments are welcome.

I say there is nothing like a little proof to back up a claim. I would rather know why I am putting something on my car, besides the "Everyone says it is the one to use" theory.

[ericscorpse]

yeah, that is a cool book...I read some of it a couple years ago but it owned me :(

[Bow]

well, that spreadsheet has all the math you need. ;)

[Nismo_Freak]

That spreadsheet has a flaw.

It does not alter pressure ratio required as the VE of the engine increases. It also does not allocate VE modification over the powerband (ie. peak VE at peak torque, reduction in VE as RPM increase).

Using this XLS will give you an incorrect plot.

[Bow]

OK then...

Correct it.

All formulas are to get the user in the ball park.

This Spreadsheet was made from the formulas straight out of the book.

To get the VE, I called and spoke to the book's Author, Corky Bell. Since he has turboed a KA24 or two, I am willing to bet he knows how to get the needed VE numbers for the formulas.

HOWEVER...

If you KNOW the information you say is missing, then modify the spreadsheet and share your knowledge.


These forumlas are for max HP at a set RPM.