I'm curious of what the flow rates are (max) through a stock intake system on a x308 XJR or XKR 4.0.

Any ideas of a number in cfm through the engine at max boost/redline?

 

Avos is your man for this but (theoretically) at max boost 11.6 psi and 6000 rpm
it will be 4 x 6000 x (14.7+11.6)/14.7 litres/min = 43,000L/min or 1520 cfm

 

Somewhere I'm seeing a Mars rover smashing into the surface in that PSI to liters conversion

 

Theoretically as I said a 4L engine displaces 4L air per rev
so a normally aspirated engine at 6000 rpm displaces 4 x 6000 = 24,000 L/min

1 cfm = 28 lpm
so that would be about 850 cu ft/min
But the supercharger is adding 11.6 psi boost.
It needs to aspirate more air than the 24,000 L /min going through the engine
The air inside the engine is at atmospheric pressure (14.7 psi) + 11.6 psi = 26.3 absolute so the volume of air at 14.7 psi aspirated by the supercharger
= 24,000 x (26.3/14.7) - yes I do apologise for the mixed units but psi/psi is a ratio, a non dimensioned number.
It makes no difference if the pressures are in psi, Bar, Pascals or whatever provided both units are the same.
That comes to about 43,000 L/min.
But it is theory. There will,of course, be losses everywhere so the true flow would be less
Safe landing though!

 

I was just lamenting the fact and making fun of our NASA engineers that even after they drilled the lander into the surface of Mars, we STILL are not going to change to the metric system...

So what would the CFM be at 18 psi boost?

 

Theoretically 24000 x (14.7 + 18)/14.7 = 53,400 lpm, 1885 cfm.
That's a 12 foot cube!!
My guess is, in the real world with losses and adiabatic heating it would be nowhere near this.
Just out of interest 43000L/min going through a 10 cm dia tube would have a velocity of about 30 km/hr

 

It's actually every second rev being that this a four stroke engine so at redline that would be 12,000 L/min. Typical VE for a non-boosted engine would around 70-90% of that and boosted might be around 130-180%.

 

Aaargh, I was calculating as a simple compressor. Stupid boy!!
Halve everything, thanks Mikey.
12000 x 1.8 = 21,600 so the calculated figure of 53000 divided by two isn't far off.

 

Let me see if I can keep up...

So as of right now we are saying at 18psi we would see something in the neighborhood of 1000 cfm?

 

Yes, absolute maximum is 900 cfm, less in the real world.

 

OK,

Thank you for the info, I'm handing the figures over to Dr. Bunson Honeydew to see what he can do with it.

"At Muppet Labs, we bring science to the streets"

 

Im sure beeker will screw it up somehow lol

 

Poor Beeker doesn't screw things up, he just always gets it when prototypes don't work as intended. Just like Wyle E. Coyote

 

need to divide by 2 as there is one intake stroke every 2 revolutions

 

As was pointed out and corrected four months ago.

 

sorry i had not gone that far down

 

The AJ27 supercharged variant will flow 1100 Kg/hr of air.

The later 4.2 litre AJ33/36/34 will flow about 1300 kg/hr of air.
This is measured on the dyno using the AFR and a coriolis fuel flow measurement.

I'm sorry but we were all metric at Jaguar.

 

The peak VE for the NA engine was about 95% at peak torque and about 80-90% at peak power.

The peak VE for the SC variants was about 135-140%.