[Land-speed] Fuel Mixture Change?

[Dave Dahlgren]

I think you are going to find the boost is going to go down a good deal as 
well if you measure it after the intercooler... it would not surprise me to 
see 8 to 10 lbs and the same power. Half of the boost is just hot air 
without an intercooler..
----- Original Message ----- 
From: "drmayf" <drmayf at mayfco.com>
To: "Skip Higginbotham" <Saltrat at pahrump.com>
Cc: <land-speed at autox.team.net>
Sent: Friday, June 05, 2009 11:50 AM
Subject: Re: [Land-speed] Fuel Mixture Change?


> Skip, here is why, I think.  YMMV, lol. The rootes is a positive 
> displacement device. It pulls the air from whatever ambient conditions 
> are. But the mass of the air is always the same per revolution. When that 
> air gets under the blower it is hot, but it is still the same mass of air. 
> That did not change. It goes through the intercooler and gets chilled 
> somewhat. But the mass of air does not change.  Just the temp changed. The 
> mass that goes into the engine is the same mass that the blower pulled in. 
> Since the mass is the same, the fuel requirements are still the same. You 
> just now have a much cooler combustion chamber and are not killing pistons 
> etc from detonation or heat. If you were still running the turbo, which is 
> a constant pressure device rather than a constant volume, then yes, the 
> fuel requirements would need changing becuase the mass of air changes. 
> Thats what makes a turbo the far better choice for power adders (but efi 
> required to make changes, lol). Cool the turbo air and it puts more mass 
> in.
>
> mayf....