Yep you be way out there. What you are suggesting is at 220 you are running
28 lbs of boost. i think not.. To answer Udo you jet for density altitude
not the phyical distance from sea level.
Dave
> -----Original Message-----
> From: owner-land-speed@autox.team.net
> [mailto:owner-land-speed@autox.team.net]On Behalf Of J I Waldron
> Sent: Saturday, April 09, 2005 1:05 PM
> To: Udo Horn; land-speed@autox.team.net
> Subject: Re: Engine Air Inlets - definite improvement
>
>
> Udo,
>
> I'm no expert, but could it be that you need more fuel because
> the engine is getting additional air via a ram air effect?
>
> A 490 Cu in engine at 7500 RPM needs about 1060 CFM
> of air (assuming no pumping losses). If an inlet duct opening,
> pointing forward, is 4x6 (24 sq inches) the air passing through
> it goes something like. (hope this table comes out)
>
> MPH CFM Factor of air needed
> 10 146.67 0.14
> 20 293.33 0.28
> 30 440.00 0.41
> 40 586.67 0.55
> 50 733.33 0.69
> 60 880.00 0.83
> 70 1026.67 0.97
> 80 1173.33 1.10
> 90 1320.00 1.24
> 100 1466.67 1.38
> 110 1613.33 1.52
> 120 1760.00 1.66
> 130 1906.67 1.79
> 140 2053.33 1.93
> 150 2200.00 2.07
> 160 2346.67 2.21
> 170 2493.33 2.34
> 180 2640.00 2.48
> 190 2786.67 2.62
> 200 2933.33 2.76
> 210 3080.00 2.90
> 220 3226.67 3.03
>
> Up to about 70 MPH the engine is having to suck air through
> the duct. At about 80 the air you are running into supplies
> what the engine needs. Above 80 you would be ramming
> excess air into the engine, requiring more fuel at higher
> speeds.
>
> Am I off in the weeds someplace?
>
> Thanks,
> Jim W.
>
>
> >Snip
> >----- Original Message -----
> >From: "Udo Horn" <vintagethunder@hotmail.com>
> >To: <jwaldron47@earthlink.net>; <land-speed@autox.team.net>
> >Subject: Engine Air Inlets - definite improvement
> >
> > If anyone can explain why the jetting would be contrary to normal tuning
> > changes, I'd be interested in hearing it. Is B'ville unique, does the
> salt
> > and or altitude effect the mixture differently than one might
> expect? Here
> > in the east we do have some dragstrips, even at altitude, where we tune
> for
> > sea level. (Definition of east coast mountain 2500 ft.)
> >
> > Regards,
> > Udo Horn
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