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"We have outdated the carburetor, but with a computer system on a fuel-injected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