Landracing Forum

Tech Information => EFI Questions => Topic started by: ronnieroadster on October 16, 2014, 08:13:53 PM

Title: Carb CFM formula for blower motor
Post by: ronnieroadster on October 16, 2014, 08:13:53 PM

Hi I'm looking for a formula that helps guide on what size CFM is needed for a given cubic inch and RPM when using a blower. The application will be for all out acceleration in Land Speed Racing  :cheers:

Title: Re: Carb CFM formula for blower motor
Post by: wobblywalrus on October 16, 2014, 09:55:00 PM

Ronnie, please post what you learn.

Title: Re: Carb CFM formula for blower motor
Post by: generatorshovel on October 16, 2014, 10:37:48 PM

Something like this ?
http://www.goodvibesracing.com/Carb_Service.htm

Title: Re: Carb CFM formula for blower motor
Post by: JimL on October 17, 2014, 08:07:21 AM

I used this when I went to EFI Technology for a blower injection system.  The calculations matched what their experience showed.  You will need a scientific calculator.

http://www.motorgeek.com/viewtopic.php?t=2747

The hardest part for blowers is finding a good map.  Turbo maps are easy, blower maps are hidden in some dark corners of the internet....in some cases.

Basically, your carb CFM will be determined by the map of the blower, as applied to the size of your engne.  Your intercooler becomes a big issue if you start using serious boost, as you will see when you work through the math.

I hope you have better results than I did.  These conversions suck money really fast, even while the parts are still in the boxes (where they remain to this day and probably forever.)

Title: Re: Carb CFM formula for blower motor
Post by: ronnieroadster on October 17, 2014, 04:27:47 PM

I found a rather simple formula on line. Using this formula the numbers I get for the combination I run are greater than the actual CFM I presently use by an additional 336 CFM. Presently I use two 600 CFM Holleys with mechanical secondary's and highly modified fuel bowls and fuel delivery lines. I would like to go to one carb replacing two with some type of Dominator. My thoughts originally the CFM of one large carb might not need to be equal to the two carbs but now I'm having second thoughts.   :?

   http://www.rbssuperchargers.com/The_Guide_to_Carburation.cfm

Title: Re: Carb CFM formula for blower motor
Post by: redhotracing on October 17, 2014, 05:17:58 PM

Ron-
The Maty boys ran a modified 850HP with their twin turbo
383 a few years back, and may be helpful in your information
quest. I do believe they ran a carb in a box and referenced psi
to an external fuel pressure regulator.

Title: Re: Carb CFM formula for blower motor
Post by: panic on October 22, 2014, 10:28:35 AM

Read my comments here:
http://victorylibrary.com/mopar/blower-carb6.htm