<VV> carbs

jvhroberts at aol.com jvhroberts at aol.com
Sun Aug 22 10:03:59 EDT 2010

 Hot rodding has been notoriously lacking in scientific rigor more times than any scientist type in the field would like to admit to! 

As such, true side by side comparisons with a single variable being the difference are exceedingly rare. 

That being said, the rules regarding carbs aren't there to make cars faster, they are there to keep costs down in those classes and/or make the fuel delivery system consistent across the board. EFI is a serious technical challenge to the tech inspectors, as the software, etc., can be deceiving far more easily than with a carb. 
The cost thing is gone nowadays, given what top notch carburetors costs for most racing classes, and standard off the shelf EFI components can provide top notch performance when selected and set up properly, in most cases. 

For a Corvair, for instance, there are lots of inexpensive injectors, throttle bodies, sensors, fuel pumps, etc. that will do a top notch job on these engines. Heck, it's not even tough to weld in port injector bungs on stock heads if you wanted MPFI! 


John Roberts


-----Original Message-----
From: djtcz at comcast.net
To: virtualvairs at corvair.org
Sent: Sun, Aug 22, 2010 9:55 am
Subject: <VV> carbs

----- Original Message(s) ----- 

From: Tony Underwood <tony.underwood at cox.net> 

At 07:28 AM 8/20/2010, John Kepler wrote: 

>The very first error is carbs make more HP than EFI. Given both are 

>optimized for making HP, EFI will ALWAYS beat a carb. 

...except on a dragstrip. ;) 

Lots of people have time slips to show for it. 

Agreed, those carbs are peaked for max hp at a narrow rpm range, and 

EFI will provide more over-all hp across the spectrum of normal 

engine operation... but for those dragstrip warriors, the carb will 

still put down the big numbers. 



I don't have a copy of the current NHRA rule book, but many classes simply 

require carbs. 

If we're talking NHRA Pro Stock, one of the most highly engineered normally 

aspirated classes, they >>HAVE< to run carburetors when they run 6.6 seconds at 

over 200 mph. 

Even NASCAR requires carbs ( one carb, actually ) but that may be changing. 


Here's a comment credited to Danny Lawrence, who is the engine builder at 

Richard Childress Racing and builds the engines for drivers Kevin Harvick, Robby 

Gordon, and Jeff Green. 

"We have outdated the carburetor, but with a computer system on a fuel-injected 

engine, it would be easy to get an unfair advantage." 

The NASCAR advantages may include better fuel mileage (weight saving, fewer pit 

stops), and improved reliability from better mixture control when the track temp 

changes 15 degrees, but I'm pretty sure ANY reduction in HP in the operating 

range of ~ 7000 -10,000 rpm would cast a deciding veto vote. 

Dan T 


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